KR20170085428A - System, Method, and Apparatus of Beam Tracking and Beam Feedback Operation in a Beam-forming based System - Google Patents

Abstract

The present invention defines a mobility method of a terminal residing in a system supporting data transmission and reception using beamforming using multiple antennas in a wireless communication system. Specifically, a method using a plurality of beams defines a measurement reference signal transmitted by a network using a different transmitting terminal or a base station, and the terminal measures and transmits the measured information to the network. More specifically, the base station transmits / receives the information measured by the UE to the base station through a method of transmitting feedback specifying each transmitting / receiving end and base station scheduling that can dynamically change the beam using operation of the UE And a terminal beam information providing method for determining the terminal and generating the terminal beam information. Accordingly, it is possible to provide a judgment criterion for fast and accurate beam and transmission / reception terminal change, and thus to reduce terminal power consumption and transmission / reception terminal change delay by preventing measurement and reporting of a wasted terminal.
In addition, the network selects the beam or beam group to be used by each terminal, informs the corresponding beam or beam group information to the terminal, and if the beam or beam group previously used by the base station and the terminal needs to be changed or updated If so, how to do it.

Description

TECHNICAL FIELD [0001] The present invention relates to a system, method, and apparatus for performing beam tracking and beam-feedback operations in a beam-forming based system,

The present invention relates to a system, method and apparatus for performing beam tracking and beam feedback operations in a beamforming based system. The present invention also relates to beam feedback and beam management in a wireless system in which a base station and a terminal using multiple antennas are present.

The present invention relates to a beamforming method and a beamforming method, and more particularly to a beamforming method and a beamforming method in a beamforming system using a beamforming method, And more particularly, to a beam-feedback operation for informing a beam-using subject (base station) without delay and a continuous beam-beam method using the same.

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is referred to as a 4G network (Beyond 4G Network) communication system or a post-LTE system (Post LTE) system.

To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed.

In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed.

In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

SUMMARY OF THE INVENTION The present invention provides a system, method, and apparatus for performing beam tracking and beam feedback operations in a beamforming based system. In addition, the present invention provides a beam feedback and beam management method in a wireless system in which a base station and a terminal using multiple antennas are present.

It is another object of the present invention to provide a method and apparatus for measuring a reference signal for selection of a beam and a transmitting / receiving terminal in an environment in which transmission / reception points having different protocol structures exist in the same base station in which an RRC connection state of the terminal is maintained , A feedback method of measured information, and a method of changing beam and transmitting / receiving terminal, and a method for allocating a specific beam and transmitting / receiving terminal reference signal of a system including a base station and a transmitting / A resource allocation and signaling method for receiving feedback of measured information, and a method for changing a beam and a transmitting / receiving terminal.

According to another aspect of the present invention, there is provided a method for measuring periodic beam information of a terminal and reporting the information to a base station, the base station and the terminal selecting a limited number of beams to transmit / receive information, And to provide a beam information feedback method and a beam changing method for enabling a beam to be changed.

According to an embodiment of the present invention, there is provided a beam feedback method of a terminal, the method comprising: receiving a beam feedback trigger condition; determining whether the beam feedback trigger condition is satisfied; The method comprising the steps of triggering beam feedback at a medium access control (MAC) layer of a terminal and transmitting a MAC CE (control element) comprising beam feedback information based on the beam feedback trigger .

According to another aspect of the present invention, there is provided a method for transmitting and receiving a signal in a terminal, the method comprising the steps of: receiving a transmission / reception unit and a beam-feedback trigger condition for transmitting and receiving a signal; determining whether the condition satisfies the beam-feedback trigger condition; The control unit controls to transmit a MAC CE (control element) including beam feedback information based on the beam feedback trigger at a medium access control (MAC) layer of the UE, A terminal can be provided.

According to another aspect of the present invention, there is provided a method for transmitting a beam-feedback-triggered condition of a base station, the method comprising: transmitting a beam-feedback triggering condition to a terminal; receiving a medium access control (MAC) control element Wherein the beam feedback information is triggered when it is determined in the MAC layer of the terminal that the beam feedback condition is satisfied.

According to another aspect of the present invention, there is provided a base station, comprising: a transmitter and a receiver for transmitting and receiving a signal and a beam-feedback triggering condition to a terminal and transmitting a medium access control (CE) control element, and the beam-feedback information may provide a base station to be triggered when it is determined that the beam-feedback condition is satisfied in the MAC layer of the UE.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

Embodiments of the present invention can provide a system, method, and apparatus for performing beam tracking and beam feedback operations in a beamforming based system. Also, according to an embodiment of the present invention, a beam feedback and a beam management method can be provided in a wireless system in which a base station and a terminal using multiple antennas exist.

1 is a diagram illustrating a multi-beam system in accordance with an embodiment of the present invention.
FIGS. 2 to 5 are diagrams illustrating a frame structure for feedbacking multi-beam ID and beam measurement values according to an embodiment of the present invention.
FIGS. 6 and 7 are diagrams illustrating a frame structure for feedbacking beam resources and beam measurements according to an embodiment of the present invention.
8 is a diagram showing a beam measurement and feedback operation of the terminal.
9 is a diagram illustrating a beam measurement and feedback operation of a UE according to an embodiment of the present invention.
10 is a diagram illustrating a beam-feedback procedure of a UE requesting a response to feedback according to an embodiment of the present invention.
11 is a diagram illustrating a method of beam measurement and beam feedback transmission of a UE when periodic dedicated feedback resources are allocated according to an embodiment of the present invention.
FIG. 12 is a diagram illustrating an operation considering whether a response is received when a base station transmits an acknowledgment to beam feedback information transmitted using an allocated dedicated feedback resource according to an embodiment of the present invention.
13 is a diagram illustrating a beam-feedback procedure of a UE using a random access resource periodically allocated by a BS according to an embodiment of the present invention.
14 is a diagram illustrating a procedure for considering a response request in feedback using periodic random access resources according to an embodiment of the present invention.
15 is a diagram illustrating a feedback method of a UE according to whether an allocated resource exists according to an embodiment of the present invention.
FIG. 16 is a diagram illustrating a method of constructing a base station beam sweeping shared reception interval and a preamble transmission method according to an embodiment of the present invention.
FIG. 17 is a diagram illustrating a method of constructing a base station beam sweeping shared reception interval and a preamble transmission method according to another embodiment of the present invention.
FIG. 18 is a diagram illustrating a method for constructing a base station beam swing sharing reception interval and a preamble transmission method according to another embodiment of the present invention.
FIG. 19 is a diagram illustrating a feedback method considering both a beam-based method using a resource allocated by a base station and a UL-directed UL feedback method according to an embodiment of the present invention.
20 is a diagram illustrating a beam feedback method using resources allocated by a base station according to another embodiment of the present invention and a feedback method considering a terminal-initiated uplink beam feedback method.
FIG. 21 is a diagram illustrating a feedback procedure in the case where the UE-initiated beam-feedback performance precedes the feedback resource allocated by the base station in another embodiment of the present invention.
22 is a diagram illustrating a process of using a different bandwidth in terminal-initiated feedback transmission according to another embodiment of the present invention.
23 is a diagram illustrating a feedback procedure according to whether or not a terminal-driven beam-feedback transmission condition is satisfied according to another embodiment of the present invention.
FIG. 24 is a diagram illustrating a terminal operation when a beam-based feedback method using a shared reception interval of a base station is a contention-based random access method in the embodiment of FIG.
25 is a diagram illustrating a frame structure of beam feedback transmitted by a UE according to an embodiment of the present invention.
26 is a diagram illustrating a frame structure of beam feedback transmitted by a UE according to another embodiment of the present invention.
FIG. 27 is a diagram illustrating a terminal operation when the beam-feedback method using the shared reception interval of the base station in the embodiment of FIG. 23 is a non-contention-based random access method.
28 is a diagram illustrating a beam measurement and a beam feedback operation of a UE using a random access procedure according to an embodiment of the present invention.
FIG. 29 is a diagram illustrating a feedback method according to a feedback resource allocation using a time threshold according to an embodiment of the present invention. Referring to FIG.
30 is a diagram illustrating a procedure for transmitting feedback using dedicated feedback resources or random access according to a specific time according to an embodiment of the present invention.
31A and 31B are diagrams showing a frame structure for beam change according to an embodiment of the present invention.
32A and 32B are views showing a frame structure for beam changing according to another embodiment of the present invention.
33 is a diagram illustrating a beam changing method of a base station according to an embodiment of the present invention.
34 is a diagram showing a beam feedback method according to an embodiment of the present invention.
35 to 49 are diagrams showing a beam feedback method according to another embodiment of the present invention.
50 is a diagram illustrating a terminal according to an embodiment of the present invention.
51 is a diagram illustrating a base station according to an embodiment of the present invention.

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of well-known functions and constructions that may obscure the gist of the present invention will be omitted. In the following description, only parts necessary for understanding the operation according to various embodiments of the present invention will be described, and the description of other parts will be omitted so as not to obscure the gist of the present invention.

With the advent of smart phones and the like, the amount of user data usage is increasing exponentially, and the demand for such data usage is increasing. This means that high bandwidth is needed and high frequency usage is required. However, the higher the frequency, the higher the signal attenuation by distance. That is, if a center frequency of 30 GHz or more is used, reduction of coverage of the base station due to signal attenuation is inevitable. There is also a problem that the use of a large number of beams is required due to the reduction of the coverage and the delay due to the use of many beams increases.

The wireless communication system considers a structure in which a single base station including a plurality of transmitting / receiving terminals capable of transmitting / receiving to support a wide physical area for improving the delay due to frequent exchange of terminal information and efficiently using resources.

Typically, there are the following systems:

A Distributed Antenna System (DAS) that transmits or receives the same signal by simply implementing a different physical transmission / reception terminal under one base station,

A remote radio head (RRH) system capable of transmitting and receiving different signals by implementing different transmit / receive stations under one base station with an antenna and a simple radio frequency (RF)

When one transmitter / receiver under one or different base stations synchronizes and transmits the same information to one user at the same time, or while one transmitter / receiver is transmitting / receiving information, the other transmitter / And Coordinated Multi-point Transmission / Reception (CoMP) systems.

The beamforming techniques and systems contemplated in embodiments of the present invention are as follows:

A. Analog Beam Forming:

- Beamforming that uses different array antennas to transmit different transmission powers and phases to superimpose the radiation patterns of the antennas to obtain antenna gain with directionality physically in a specific direction

- Beam can be set from multiple antennas in desired direction without channel information of desired target receiver.

- Only transmit / receive in one direction at a time (radiation pattern in the other direction is offset

- When using multiple antennas, it is possible to form a beam with a high directivity and reach the farther with the same power and a large antenna gain (beam width / length difference according to the number of antennas)

- Long length but only narrow area

B. Digital Beam Forming:

- In multi-antenna transmit / receive environments, using multiple channel information between antennas having different intensities, different coding is applied to the information before transmission to form a plurality of orthogonal beams canceling desired interchannel interference Technology

- Utilizing different channel characteristics by using pre-coding on data transmitted by each antenna

- Single-user MIMO support and multi-user MIMO support

C. Hybrid Beam Forming:

- A technology that uses analog beamforming and digital beamforming simultaneously.

- A technique that uses digital beamforming using different pre-coding techniques for each antenna for beams and transmit antennas formed by analog beamforming.

The techniques described in the embodiments of the present invention can be one of techniques using beam and beamforming formed by the analog beamforming, the digital beamforming, and the hybrid beamforming. Also, a method for occupying and transmitting any resource that can be classified into physical or frequency / time / code / signal for information transmission is referred to as beamforming, and applicable to all systems in which the occupied resources are called beams.

In addition, the related technologies used in the wireless communication technology conforming to the 3GPP standard are as follows.

A. Uplink, uplink transmission (transmission from a station to base station) transmission:

- Basically, it should be transmitted using reserved resources through resource allocation of base station (eNB, base station).

- A UE that requires uplink transmission needs to allocate resources for uplink transmission by transmitting a scheduling request (SR) allocated in advance by the base station (specifically, a random access channel capable of contention-based transmission with other UEs, and an uplink control channel (BSR) for transmitting uplink data, RACH).

B. Channel measurement information feedback:

- An existing technology that informs the base station about the channel information measured by the terminal is channel measurement and feedback in the physical layer. Examples of such information include reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR), signal to noise and interference (SINR), a channel quality indicator (CQI), a channel state inforamtion-reference signal (CSI-RS), and the like . This information can be obtained by measuring the signal transmitted by the base station (CRS, cell specific reference signal, DRS (dedicated reference signal), CSI-RS, demodulation reference signal (DMRS) .

The UE can transmit the acquired information using resources allocated by the BS according to the UL transmission rule. Without the resources allocated by the base station, it is a conventional wireless communication technology that there is no need to provide or provide such information to the base station.

In order to improve the efficiency of existing wireless communication systems, signals for maintaining connectivity such as control signals and reference signals are transmitted using common frequency channels and time resources for all users to listen to.

On the other hand, in the case of a multi-antenna using beamforming system in which resources such as frequency channels, time, beams, and codes are differently allocated and used for different beams, a beam characteristic (direction, Channel, etc.) may cause the resource to be unusable.

For example, in a system in which a plurality of analog beams are used for transmission / reception, a terminal and a base station transmit / receive information by selecting a specific beam estimated to have a high performance. At this time, the base station reserves the best (or most problematic) beam resource known to the base station at the time of reserving the resource, in order to reserve resources for uplink transmission of the terminal. However, changes in the channel of the reserved beam resource may occur due to terminal movement or other variables (e.g., sudden traffic obstacles, climate change, etc.). When the uplink information transmission fails due to the change in the characteristics of the reserved beam resource, there is no way to quickly solve the problem with the existing technology.

Therefore, in the case of a multi-antenna beamforming system in which different resources such as frequency channel, time, beam and code are allocated and used for different beams, beam status information exchange between the terminal and the base station and fast beam changes can be tracked and applied A beam management technique is required.

In addition, in the case of the existing technology for transmitting the signals for maintaining the connectivity such as the control signal and the reference signal using the frequency channels and the time resources that are commonly receivable for all users, if the channel state being used becomes poor, The method is a method of changing to another channel of the other frequency when another channel of another frequency exists, or attempting to reconnect to the network after declaring a failure if the radio link failure condition is satisfied .

However, in the case of a beamforming system using multiple antennas in which different resources such as frequency channels, time, beams, and codes are allocated and used differently for different beams, even if the characteristics of the beams used are poor, There is a high probability of existence, and an opportunity to maintain the connectivity through this is given to the terminal, and a technology that can utilize it is needed.

In the case of existing technologies (such as Omni antenna use, digital beamforming systems, etc.), if the channel conditions are getting worse, the way to overcome them is to change to another channel of another frequency, RLF) condition is satisfied, there is no way to attempt to reconnect to the network after the failure is declared.

However, in a system using analog beamforming, even if the channel state of the beam used is bad, there is a high possibility that another beam usable at the same position exists and the connection can be maintained.

In the prior art, a UE is a channel information feedback in which only a physical layer can provide a resource that is being used in a Node B, in particular, a channel state change notification to the Node B. In this conventional technique, the UE receives the specific signal (CRS, DRS, RS, Beam RS, CSI-RS, etc.) transmitted from the base station and grasps the channel state, (PUCCH), a physical uplink shared channel (PUSCH), or the like) to the base station by using a resource capable of uplink transmission, which is allocated by the base station after the CQI, RI, PMI, (Or a resource allocation request for uplink transmission) to the base station and then allocate resources and transmit channel state information.

However, in the case of a multi-antenna beamforming system in which different resources such as frequency channel, time, beam, and code are allocated and used differently for different beams, unique resources (e.g., analog beams, hybrid beams Etc.), it is necessary to notify the base station of other available resource information and allocate the resource to the base station in the future.

In the embodiment of the present invention, in a beamforming, especially a system and an environment using multiple beams, of a wireless communication system in which a base station and a terminal using multiple antennas exist, beam information observed and measured by the terminal is notified to the base station without delay And to design a continuous beam-tracking method using the beam-feedback operation.

1 is a diagram illustrating a multi-beam system in accordance with an embodiment of the present invention.

Referring to FIG. 1, a system according to an embodiment of the present invention includes a base station and a terminal that form analog beams having various directions. Here, the analog beam used by the base station and the terminal may be composed of a plurality of small antenna arrays, and wireless transmission / reception can be performed in one direction using one antenna array group at a time. At this time, if one or more antenna array groups are simultaneously operable, radio transmission / reception can be performed in more than one direction at a time.

In the embodiment of the present invention, in a multi-antenna using beamforming system in which resources such as a frequency channel, time, beam, and code are differently allocated and used for different beams, one or more base stations (or transmitting / And an environment in which one or more beams are used to transmit / receive using a pair of beams at a time is considered as a basis. In addition to this, the base station or the terminal does not use a plurality of beams, for example, one or more base stations, one terminal uses one beam, or one base station and one terminal uses one or more beams A possible beam information exchange method is proposed.

In more detailed operation, the terminal exchanges beam information in use in the same base station (or transmitting / receiving end) through three steps of 1) measurement of beam information, 2) provision of beam information, and 3) At which time a suitable beam is found and the corresponding beam can be used. In a multi-antenna beamforming system that allocates and uses resources such as frequency channel, time, beam, and code differently for different beams, the base station and the terminal detect the channel status of the transmit / receive beam in real time, Be able to maintain and change the beam. The following actions are required for this.

A. Beam Measurement

- The beam measurement is performed to measure the channel of beam pairs that can result in a combination of various beams between the terminal and the neighboring base station.

The beam measurement may be periodic or aperiodic, and may be performed by a terminal or a base station.

The embodiment of the present invention is not limited by any beam measuring method, and it can be assumed that the terminal or the base station can measure the channel state of the beam pairs with each other.

In the embodiment of the present invention, the terminal performs an operation of measuring beam information in a certain manner, and as a result, performs an operation of updating and measuring the measured value according to each beam information measurement The environment can be assumed.

B. Beam Feedback or Beam Reporting

- Beam feedback is an act of informing the base station of the beam information measured by the terminal.

- Feedback from the terminal (or base station) is essential because the base station (or terminal) that is the transmitting terminal can not know the downlink (or uplink) beam information.

The beam information feedback may be periodic or aperiodic, and may be performed by a terminal or a base station.

- The embodiment of the present invention mainly describes the operation of transmitting the beam information measured by the terminal to the base station. However, the scope of the present invention is not limited to the beam feedback of the terminal or the reporting, but may be applied correspondingly to the operation of transmitting the measured beam information to the terminal. Therefore, procedures for beam feedback and beam modification of the terminal below can be applied equally / similarly to the operation of the base station.

In the embodiment of the present invention, the beam feedback information, the beam feedback information may be beam state information (BSI), and may be beam refinement information (BRI).

C. Change Beam

The base station or the terminal can determine a beam pair to be used in future based on the received beam feedback information.

The base station or terminal may perform various operations to use the determined beam pairs.

The main contents of the embodiments of the present invention will be summarized as follows. Proposed Medium Access Control (MAC) Layer action that can track the available beam changes and change the beam in use, in a base station / terminal system that communicates using an analog beam (beam with fixed direction).

A method and a procedure for providing (feedback) beam information measured through an embodiment of the present invention to a counterpart and a method for changing a beam being used by both parties using the same are provided.

A. Method for determining necessity of beam change of terminal

- Specifically, when the performance of the beam being used is deteriorated or a beam (another) is observed that is better than the beam being used, the beam measuring subject (terminal) judges the necessity of changing the beam

- The UE determines a feedback transmission for requesting the base station and the determined information and beam information

B. Beam feedback configuration of the terminal

- The beam identification method (Identification)

a. When the beam ID of the received or received reference signal including the beam ID is known:

a1. Feedback including this ID

b. Receiving reference signal without beam ID:

b1. The beam reception time, the reception frequency position (or the information of the base station antenna port which can be inferred to the corresponding frequency position (having prior information), and the like) instead of the beam ID.

b2. The base station remembers which beam it has transmitted to which port at what time, and maps the received feedback information to the beam selection.

C. Terminal beam feedback method

- Available uplink beam feedback method:

a. Dedicated Feedback: Uplink beam feedback used by a base station to allocate resources such as a specific beam / time / frequency that operates on a scheduling basis to a specific UE and to transmit the beam information to the base station

b. UL Beam Sweep Feedback: The base station sets up some intervals for sweeping available beams, and the terminal repeatedly transmits the same information in this interval to the receiving beams of different base stations, or 2) An uplink beam feedback (hereinafter referred to as " uplink beam "

b1. Even if the beam changes, it can be transmitted without any problem

b2. It is possible to schedule and use a specific resource of a corresponding interval to a specific UE

b3. (E.g. 3GPP LTE RACH) so that an unspecified number of terminals can freely transmit the corresponding interval

- a main beam feedback method according to an embodiment of the present invention

a. The terminal basically uses Dedicated Feedback at all times, and performs uplink beam sweep feedback when recognizing the necessity of changing the beam in use.

b. If the terminal uses Dedicated Feedback and recognizes the necessity of changing the beam in use, if the performance degradation of the existing beam is estimated, UL Beam Sweep Feedback

c. Other feedback methods according to various embodiments described below are available.

The operation and proposed procedures of the present invention will be described below using various specific embodiments.

A terminal (UE), which is referred to in the following embodiments, refers to a beam measurement subject that performs beam measurement, and a base station (eNB) transmits a reference signal for beam measurement, It refers to a beam-using subject that uses the beam information through measurement, when the subject informs the beam through feedback, and allocates resources to the subject.

In the embodiment of the present invention, the terminal and the base station are used as a beam measurement and feedback performing entity, a beam reference signal transmission and a resource allocation entity, but their roles are not limited to the terminal and the base station. The base station may be a subject performing beam measurement and feedback, and the terminal may be a subject that transmits a beam reference signal or allocates resources.

In the following embodiments, the best beam (or the best beams) refers to a beam measuring subject and a beam-using subject, which are assumed to have the best performance among the analog beams that can be used by the beam- (Or pairs of beams) consisting of the beams of these two subjects when one beam of beams is determined, or may mean two beams in a beam pair (or beam pairs), respectively. In the embodiment of the present invention, the best beam is generally used in order to communicate with a beam measuring subject (terminal) in a beam-using subject (base station) within a best beam pair measured according to a reference signal transmitted by a beam- However, the present invention is not limited to this, and may mean various examples of the best beam described in the embodiment of the present invention.

The beam measuring subject may inform all the information of the best beam pair (or pairs of beams) to the beam-using subject through feedback, or may notify only one beam information to be used by the beam-using subject to the corresponding beam-measuring subject. (E.g., the terminal may inform only one beam information belonging to the base station to be used when the base station transmits / receives information to / from the terminal)

≪ Measurement information transmitted by the measurement subject by beam feedback >

The feedback information measured by the UE and transmitted to the Node B may be one of the following configurations.

A. beam feedback information consisting of a bit stream (bit map) + beam quality measurement values (RSRP, RSRQ, CQI, SINR, SNR, RSSI,

FIG. 2 is a diagram illustrating a frame structure for feeding back multi-beam ID and beam measurement values according to an embodiment of the present invention.

Referring to FIG. 2, an embodiment of a MAC-CE structure for transmitting N beam information (ID 9 bits, BRSRP 7 bits) can be confirmed.

- BI (9-bit): Field indicating the beam index.

- BRSRP (7-bit): Field indicating the RSRP of the beam.

- In the embodiment of FIG. 2, the BI is represented by 9 bits and the BRSRP by 7 bits. However, each of the fields may be a different number of bits.

FIG. 3 is a diagram illustrating a frame structure for feeding back multi-beam ID and beam measurement values according to an embodiment of the present invention.

Referring to FIG. 3, an embodiment of a MAC-CE structure for transmitting N beam information (eNB beam ID 3 bits, BRSRP 7 bits) can be confirmed.

- RBI (3-bit): A field indicating the beam index.

- RB-RSRP (7-bit): field indicating the receiving RSRP of the beam.

- R: reserved bit, set to "0". In the embodiment of FIG. 3, the RBI is 9 bits and the RB-RSRP is 7 bits. However, each of the fields may be a different number of bits.

B. beam feedback consisting of a base station beam ID (bit stream) + a terminal beam ID (bit stream) + beam quality measurement values (RSRP, RSRQ, CQI, SINR, SNR, RSSI, Information

4 is a diagram illustrating a frame structure for feeding back multiple beam ID and beam measurement values according to an embodiment of the present invention.

Referring to FIG. 4, an embodiment of a MAC-CE structure for transmitting N beam information (eNB ID 9 bits, UE ID 5 bits, BRSRP 7 bits) can be confirmed.

- BI_1 (9-bit): field indicating the beam index of the base station.

- BI_2 (9-bit): field indicating the beam index of the terminal.

- BRSRP (7-bit): Field indicating the RSRP of the beam.

5 is a diagram illustrating a frame structure for feeding back multi-beam ID and beam measurement values according to an embodiment of the present invention.

Referring to FIG. 5, an embodiment of a MAC-CE structure for transmitting N beam information (eNB beam ID 3 bits, UE beam ID 3 bits, BRSRP 7 bits) can be confirmed.

- RBI_1 (3-bit): A field indicating the beam index of the base station.

- RBI_2 (3-bit): A field indicating the beam index of the UE.

- BRSRP (7-bit): Field indicating the RSRP of the beam.

The beam ID may be a unique beam ID of each base station and a terminal, and a reference signal for beam measurement may be transmitted including the corresponding beam ID information.

The beam ID may be a beam ID (non-intrinsic) specifying the position of a resource to which each base station and the terminal transmits a reference signal for beam measurement, and the reference signal for beam measurement may be encoded Or may be scrambled or transmitted by generating a sequence.

The beam ID and beam measurement information may be transmitted in various forms such as UL Control Information, RRC Message Information Element (RRC) IE (RRC-IE) Lt; / RTI >

The beam measurement information may be various measurement values such as RSRQ, CQI, SNR, SINR, and RSSI as well as RSRP.

C. The method of specifying the base station beam ID as a part of the reception resources such as the reception time, reception position, reception antenna port, etc. of the beam measurement reference signal received by the terminal and the corresponding beam quality measurement values (RSRP, RSRQ, CQI, SINR, SNR, RSSI, ...)

c1. The UE receives the received beam measurement reference signal (e.g., a reception time, a slot number, a frame number, a receiving cell ID, a transmitting terminal ID, a transmitting antenna port, a receiving antenna port, a receiving beam ID, Receive carrier number, transmission channel name, etc.).

c2. In the case where the BS and the UE are aware of a certain rule regarding the transmission / reception resources of the beam measurement reference signal as variables, it is possible to perform beam feedback including the received resource information instead of the received unique beam ID.

- For example, if the number of base station transmit antenna ports is repeated for each number of resources (eg, sub carrier, symbol, slot, sub-frame, etc.) and there is a promise that the beam measurement reference signal will be transmitted

- For example, if there is a promise that the same beam will be transmitted repeatedly for a particular resource (sub-frame, any period, slot, sub-carrier, etc.). At this time, the pattern may have some criterion (for example, from the top of the base station using frequency band, from the bottom to the center, etc.).

- or mod (x, 2), or mod (x, 4), or mod (x, 8) in the receiving sub-carrier number x mod (x, 10), or mod (x, 16), etc.)

The terminal knowing the rule can transmit any feedback by replacing the beam ID with the received resource information as described below.

6 is a diagram illustrating a frame structure for feedbacking beam resources and beam measurements according to an embodiment of the present invention.

Referring to FIG. 6, an example of a frame structure (MAC-CE) for feeding back a beam measurement reference signal transmission port number (3-bit) and a beam measurement value is shown.

- Port #: field indicating the transmission port number The port # may be the reception port number.

7 is a diagram illustrating a frame structure for feedbacking beam resources and beam measurements according to an embodiment of the present invention.

Referring to FIG. 7, a frame structure (MAC) for feeding back a beam measurement reference signal transmission time (6-bit), a transmission antenna port number (3-bit) -CE) (P # = Port #).

 time #: A field indicating a beam measurement reference signal transmission time. The port # may be a reception port number. The reference signal transmission time may be a reference signal reception time. The reference signal transmission / reception time may not necessarily be a time, but may be a resource identifier (e.g., a channel number, a frequency number, a slot number, a frame number, a coverage area number, etc.). The sizes of the reference signal transmission / reception time and the transmission / reception port number are not limited to 6-bit and 3-bit, respectively.

In addition, in the beam-feedback transmission frame, when it is desired to use any (for example, the best first transmitted first) beam included in the feedback information transmitted from the terminal in the future, it is requested to change the used beam to the corresponding beam A Beam Change Request Indicator may be included in a bit (or in the form of a specific bit ID bit, or a 1 bit indicator attached next to each beam ID).

≪ Feedback & Reporting Method >

In the following embodiments, various operations related to beam feedback transmission of a terminal and beam-feedback resource allocation and beam-feedback reception operations of a base station for the terminal will be described using various specific embodiments.

In a system such as LTE in which a BS controls and allocates resources for uplink transmission and a UE using the resources, the existing UE can not transmit feedback only when the existing technology is used in the following manner:

8 is a diagram showing a beam measurement and feedback operation of the terminal.

Referring to FIG. 8, in operation 810, the terminal measures the beam. In operation 820, the terminal selects a preferred beam based on the beam measurement result.

In operation 830, the UE checks whether there is a feedback request from the BS. If there is a feedback request, proceed to operation 840, and if there is no feedback request, proceed to operation 850. [ The feedback request may include a case where uplink resources for beam feedback are allocated.

In operation 840, the UE can feedback the measured beam information using the uplink resources allocated from the BS. 850 operation, the UE can not transmit the beam information to the base station since there is no uplink resource for feedback of the beam information. The UE may terminate the procedure or feedback the beam information when the uplink resource is allocated in the future.

As described above, if there is no uplink resource that can transmit the beam measurement result, the UE can not perform the uplink transmission if it is not allocated from the base station. As a result, sudden changes in the beam state, for example, a sudden decrease in serving beam quality, or the need to use another adjacent beam, can not be transmitted to the base station at the same time. This problem is further highlighted in a very high frequency environment where the beam width becomes narrower and the number of beams to be transmitted / received increases as the base station rotates. The base station can transmit / receive only a limited number of beams at a time, and the terminal has to wait for a long time to allocate the resources of the base station in order to transmit the feedback to the base station using the desired beam.

Therefore, in the case of a multi-antenna using beamforming system in which resources such as frequency channels, time, beams, and codes are differently allocated and used for different beams, the terminal triggers and transmits beam feedback information Protocols, and systems that are capable of communicating with others. Triggering of beam feedback transmission in such a terminal requires determination and information transmission start using a comparison of beam measurement values in an upper layer instead of simple feedback using allocated resources in a physical layer that was supported in existing wireless communication technologies such as LTE .

Specifically, the measurement value of each beam (or beam pair) obtained by measuring the beam measurement signal is an instantaneous value, and its value may change like a wave depending on the channel fluctuation. Changing the beam used at such a moment to another beam has a great risk of assuring the correctness and performance of the change. Therefore, the terminal should be able to determine the beam change by comparing the measured values of different beams after taking a certain number of the measured values into account, such as arithmetic mean / geometric mean / moving average. The operation of taking the average of the instantaneous beam information measurement values and comparing the information of different beams is appropriate to be performed in a higher layer (MAC, RLC, ...) than the physical layer, and transmitting the beam feedback And the operation of selecting resources to transmit beam feedback is also performed at an upper layer.

In the embodiment of the present invention, the transmission of the feedback information of the channel is performed by calculating the average of the beam information by the terminal determination, not the base station allocation resource, comparing the different average beam measurement values, and determining the beam to transmit the beam feedback. Or perform an intra-cell channel management operation requesting resource allocation in an upper layer of the UE. The method proposed by the embodiment of the present invention is a very unique and new method when all existing channel information feedback is performed in the physical layer (PHY).

9 is a diagram illustrating a beam measurement and feedback operation of a UE according to an embodiment of the present invention.

In operation 910, the terminal measures the beam. The terminal may receive a beam measurement reference signal (BRS) transmitted by the base station and measure and measure it for different receive beams to obtain a beam quality measurement value for each base station transmit beam and terminal receive beam pair.

In operation 920, the terminal may select a preferred beam. The selected beam may be a best beam. The terminal may compare the beam quality measurements to each other and select the best terminal receive beam for each base station transmit beam. In addition, the terminal can select a preferred beam (or beam group) by dividing the beam (or beam group) that the base station may transmit in the order of the transmission beams having the best quality.

In operation 930, the terminal may determine whether it is necessary to change the beam currently in use to another beam.

The condition that the terminal determines that beam feedback transmission is necessary is as follows. The following conditions can be named as beam change trigger condition or beam feedback trigger condition.

A. The channel quality or performance of the serving beam (or busy beams) is less than a certain threshold. Here, the threshold value may be a constant having a fixed value according to the standard, or may be set by a base station using an RRC message, a MAC-CE, a PHY DCI, or the like.

a1. Current beam measurement <Threshold.

a2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

a3. The current beam may be one beam, or may be one or more beams that the base station can transmit to the current terminal. If there is more than one beam, it may be triggered when at least one beam measurement value of the one or more beams is less than the threshold, or may be triggered if all of the beams being used are below the threshold.

a4. The threshold may be any absolute value assigned by the base station to the RRC signal, and may be any absolute value selected by the UE itself, for example, a predetermined PDCCH error probability (e.g., 10%, 5%, 2% ) Value, as a matter of course.

B. When the channel quality or performance of any other beam other than the currently used beam (serving beam, scheduling beam) is greater than or equal to a certain threshold

b1. New beam measure> Threshold.

b2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

b3. It is a matter of course that the new beam may be one beam or at least one beam that can be transmitted by the base station to the current terminal. In case of more than one beam, it is also possible to trigger the beam when the measurement value of at least one of the beams is equal to or greater than the threshold, or to trigger when all of the new beams exceed the threshold.

b4. The threshold may be any absolute value assigned by the base station to the RRC signal, and may be any absolute value selected by the UE itself, for example, a predetermined PDCCH error probability (e.g., 10%, 5%, 2% ) Value, as a matter of course.

C. If the channel quality or performance of another beam is better than a certain threshold / offset compared with the beam currently in use

c1. New Beam Measure> Current Beam Measure + Threshold.

c2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

c3. The current / new beam may be one beam, or may be one or more beams that the base station can transmit to the current terminal. If there is more than one beam, a comparison of at least one of the one or more beams to the new and current beam is c1. And both new and current beams are c1. It is needless to say that it can be triggered.

c4. The threshold may be any absolute value assigned by the base station to the RRC signal, and may be any absolute value selected by the UE itself, for example, a predetermined PDCCH error probability (e.g., 10%, 5%, 2% ) Value, as a matter of course.

D. The channel quality or performance of the currently used beam (serving beam, scheduling beam) is below a certain threshold and the channel quality or performance of any other beam other than the currently used beam (serving beam, scheduling beam) Or more

d1. (Current beam measurement value <Threshold_out) & (new beam measurement value> Threshold in)

d2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

E. When a timer (e.g., Feedback Timer) has expired

e1. And the uplink beam feedback is not transmitted during the corresponding timer time.

e2. When the uplink resource allocation is not received during the corresponding timer time.

e3. When a successful uplink transmission can not be performed during the corresponding timer time, and the like.

F. The currently used beam (base station beam, terminal beam, or beam pair) derived through the beam measurement is not included in the top K (or K%) of the total beam (base station beam, terminal beam, or beam pair) When not.

G. When the currently used beam (base station beam, terminal beam, or beam pair) derived through the beam measurement is included in the lower K (or K%) of the total beam (base station beam, terminal beam, or beam pair) .

H. In case of receiving a response (HARQ ACK, RLC ACK, Feedback ACK, etc.) to be received during a certain time (Timer) after transmitting feedback using the dedicated feedback resource allocated by the base station.

h1. The feedback message transmitted by the UE using the pre-allocated dedicated feedback resource may include information requesting a response or acknowledgment of the base station to the feedback.

h2. The response request information may be a bit existing at a predetermined position in a predetermined PHY or MAC message. gt;

h3. The response request information may be a predetermined sequence.

h4. The response may be received within a certain time after the feedback information is sent.

h5. The feedback message transmitted by the UE using the pre-allocated dedicated feedback resource does not include a special response request message, but a response can be requested to the base station by a predetermined method as follows.

h6. For a feedback message, the always-on response may be predetermined in advance.

h7. The base station exchanges some signal / message before transmitting the feedback message so that the base station can transmit a response for several (one or more) feedbacks.

h8. The UE and the base station exchanges some signal / message before transmitting the feedback message, and the base station can send a response to the feedback to be transmitted until after this condition is canceled / canceled.

The corresponding embodiment corresponding to H will be described with reference to FIG.

10 is a diagram illustrating a beam-feedback procedure of a UE requesting a response to feedback according to an embodiment of the present invention. Referring to FIG. 10, a beam-measuring subject 1010 transmits a beam- And may receive a response from the beam using subject 1020. [ The beam measuring subject 1010 is a terminal and the beam using subject 1020 is a base station. However, the present invention is not limited to this, and the beam measuring subject may be the base station and the beam using entity may be the terminal.

 In operation 1040, the beam-using subject 1020 may allocate feedback resources to the beam-measuring subject 1010. The feedback resource may be a periodic dedicated feedback resource. In operation 1045, the beam-using subject 1020 may transmit information on the allocated feedback resource to the beam-measuring subject 1010. 1040 operation and 1045 operation may be collectively referred to as a feedback resource allocation process. The beam-using subject 1020 can transmit information on the feedback resource to the beam-measuring subject 1010 using the currently used best beam. In operation 1050, the beam-using subject 1020 transmits a reference signal for beam measurement . The beam using subject 1020 can transmit a reference signal for beam measurement for each of a plurality of beams.

In 1055 operation, the beam measurement subject 1010 measures the beam. The beam measurement subject 1010 can select the best beam based on the beam measurement result. The beam measuring method and the beam selecting method can use the beam measuring and beam selecting method already described.

In operation 1060, the beam measuring subject 1010 may transmit the beam measurement result to the beam using subject 1020. [ The beam measurement result may include the contents of the feedback resource described in the above embodiments. The beam measurement subject 1010 may transmit feedback using the dedicated dedicated feedback resource. In the present embodiment, the beam measurement subject 1010 can transmit feedback including a response request. For the contents of the response request, refer to the description in the H embodiment.

In operation 1065, the beam measurement subject 1010 determines whether a response to the feedback has been received. When receiving the response to the feedback, it is possible to confirm that the beam-using subject 1020 has received information on the best beam fed back by the beam-measuring subject 1010, and change the transmission / reception beam to the best beam. If the response to the feedback is not received in operation 1065, the operation proceeds to operation 1070.

In operation 1070, beam measurement subject 1010 may perform beam feedback. The beam feedback can be performed using a random access procedure. The beam measuring subject 1010 can perform feedback using the current best beam according to the beam measurement result. The beam measurement subject may send feedback in 1071 operation and receive a response to the feedback in 1072 operation. If it does not receive a response to the feedback in operation 1072, it can again send feedback in operation 1073 and receive a response to feedback in operation 1074. The transmission and response procedure of the feedback information using the random access procedure is a new procedure and can be performed a plurality of times until a response is received from the beam using subject 1020. [

In operation 1075, the beam-using subject 1020 can allocate periodic dedicated feedback resources using the perceived best beam.

I. When the transmission (data transmission / reception) using the currently used beam fails within a certain time (timer, etc.) more than a predetermined number of times

J. When the beam feedback transmission is not performed on the uplink for a predetermined time (timer)

K. If there is an uplink transmittable resource (e.g. SR, Random Access, UL scheduled PUSCH, PUCCH, ...) and one or more of the above conditions are met

In these conditions, the threshold may be any absolute channel estimate or measurement value (e.g., RSRP, RSRQ, RSSI, etc.) that the base station and / or the terminal can estimate that the communication can not be smooth, , CQI, SNR, etc.).

The threshold may be notified to the UE by the BS (known method: a specific parameter in the RRC message, a MAC data, a specific parameter in the MAC-CE, a specific parameter in the DCI, etc.) Alternatively, the terminal may be configured to be implemented.

The conditions may be used in combination to satisfy one or more conditions simultaneously.

2. Classification of feedback method according to feedback resource allocation cycle

2. 1. Periodic feedback transmission method

A. A method in which a resource assignable entity (base station) allocates resources at a predetermined time interval and a measurement subject (terminal) transmits feedback using the resource

a1. The resource allocatable entity allocates resources such as a periodic frequency / time / resource block / subframe / symbol to a specific UE, and provides information on the allocated resource location and the UE feedback transmission period to the UE .

a2. The resource allocation information providing method includes a preamble, an RRC connection reconfiguration, an IE in an RRC signal, a MAC Control Element (MAC-CE), a broadcast message (eg, a master information block (MIB) ), ...), PHY downlink control information (PHY DCI).

a3. The beam-feedback may include any signal that can be transmitted through an uplink control channel (eg, PUCCH) or an uplink data channel (eg, PUSCH), for example, UCI Multiplexing, MAC-CE, MAC PDU, Preamble, RRC- , RRC signal or the like and includes information such as base station beam ID, beam pair ID, receiving beam ID, number of users, channel capacity, RSRP, RSRQ, SNR, SINR, RSSI, CQI, PMI, RI, can do.

a4. The uplink resource for beam-feedback may be a resource that can be transmitted / received using a serving beam currently being used by a corresponding terminal known by the base station, or may be a resource / Receive resources, or it may be a resource in any interval that sweeps and receives multiple beams that allow the base station to cycle through and use multiple available beams.

a5. The resources for periodic feedback allocated by the base station can be allocated so that the base station can receive the best using one or more beams used by a terminal known at the current scheduling time. At this time, the base station may transmit the beam information to be received by the resource to the terminal by including the information in the scheduling information in the form of "base station beam ID".

11 is a diagram illustrating a method of beam measurement and beam feedback transmission of a UE when periodic dedicated feedback resources are allocated according to an embodiment of the present invention.

11, the beam measuring subject 1110 is a terminal and the beam using subject 1120 is a base station. However, the present invention is not limited to this, and the beam measuring subject may be the base station and the beam using entity may be the terminal.

In operation 1140, the beam-using subject 1120 may assign a feedback resource to the beam-measuring subject 1110. The feedback resource may be a periodic dedicated feedback resource. In operation 1145, the beam-using subject 1120 may transmit information about the allocated feedback resource to the beam-measuring subject 1110. [ 1140 operation and 1145 operation may be collectively referred to as a feedback resource allocation process. The beam-using subject 1120 can transmit information on the feedback resource to the beam-measuring subject 1110 using the currently used best beam. In operation 1150, the beam-using subject 1120 may transmit a reference signal for beam measurement. The beam using subject 1120 can transmit a reference signal for beam measurement for each of a plurality of beams.

In operation 1155, beam measurement subject 1110 measures the beam. The beam measurement subject 1110 can select the best beam based on the beam measurement result. The beam measuring method and the beam selecting method can use the beam measuring and beam selecting method already described.

In operation 1160, the beam measuring subject 1110 may transmit the beam measurement result to the beam using subject 1120. The beam measurement result may include the contents of the feedback resource described in the above embodiments. The beam measurement subject 1110 may transmit feedback using the dedicated dedicated feedback resource. In the present embodiment, the beam measurement subject 1110 may transmit feedback including a response request.

At this time, the allocated resources can be allocated to an optimal beam (or beam group) capable of communicating with a terminal known to the base station. In case of changing a beam or a group of beams to be communicated with a terminal, the periodic dedicated feedback resource may be changed and reallocated. Alternatively, the base station may change the beam to be used with the terminal to a beam to be used for the new terminal in the beam used for the existing terminal, and may not transmit the special periodic dedicated feedback resource allocation information to the terminal have.

The order of the periodic dedicated feedback resource allocation process and the reference signal transmission and measurement process for beam measurement does not necessarily have to be the same order. After transmitting the reference signal for beam measurement and performing the beam measurement Periodic dedicated feedback resources may be allocated.

FIG. 12 is a diagram illustrating an operation considering whether a response is received when a base station transmits an acknowledgment to beam feedback information transmitted using an allocated dedicated feedback resource according to an embodiment of the present invention.

Referring to FIG. 12, the beam measurement subject 1210 is a terminal and the beam usage subject 1220 is a base station. However, the present invention is not limited to this, and the beam measuring subject may be the base station and the beam using entity may be the terminal.

The operation of 1240 to 1260 of FIG. 12 refers to the description of operations 1140 to 1160 of FIG.

The response request may be always necessary (HARQ, RLC ACK, etc.) due to the nature of the beam feedback transmission, and the UE may explicitly transmit a response request within the beam feedback transmission. (If ACK request field exists, indication is transmitted)

In operation 1265, the beam measurement subject 1210 may determine whether it has received a response to the feedback. Upon receiving the response to the feedback, it can be confirmed that the beam-using subject 1220 has received information on the beam fed back by the beam-measuring subject 1210. [ If it is determined that the response to the feedback is not received in operation 1265, the operation can proceed to operation 1070.

In operation 1070, the beam measurement subject 1210 may declare a link failure and attempt to reconnect to the network with a new beam. At this time, the beam attempting to reconnect to the network may be the best beam identified in 1255 operation. If the terminal has not received a response request for a certain period of time despite repeated attempts of the feedback including the response request, the terminal determines that the current beam status is no longer suitable for the uplink communication and issues a quick link failure declaration and a new beam And performs the reconnection procedure to the network using At this time, if it is determined that the uplink feedback transmission is not performed through the feedback resource allocated for the predetermined time, the link failure can be declared to the corresponding terminal.

Also, the network can retain the information of the terminal that has declared the link failure for a certain period of time, and can quickly support reconnection using another beam of the corresponding terminal. Also, the network may disconnect the terminal that has declared the link failure (discarding the terminal information), and may follow the existing reconnection procedure when the terminal attempts to reconnect.

In operation 1275, the beam-using subject 1220 may allocate periodic dedicated feedback resources to the perceived best beam. The best beam that is recognized may be the best beam information included in the feedback that is made from the beam measurement subject.

B. Periodic feedback When the transmission resource is not allocated, the measurement subject (UE) periodically transmits feedback information through a method such as a scheduling request or a random access procedure, etc. How to send

b1. In the case where a resource capable of sending a resource allocation request (scheduling request) is allocated in an uplink period even if there is no resource capable of periodically transmitting feedback, the measuring entity periodically transmits the resource allocation request, The uplink resource can be allocated and the feedback can be transmitted using the resource.

b2. The uplink resource for beam-feedback may be a resource that can be transmitted / received using a beam currently being used by a corresponding terminal known by the base station, or may be a resource that can be transmitted / Or it may be a resource within any interval that sweeps and receives multiple beams that allow the base station to cycle through and use the multiple available beams.

A method of periodically allocating unique resources to each mobile station to transmit uplink beam feedback is disadvantageous in that the amount of resources to be allocated increases as the number of users increases and the number of beams operated by the base stations increases. To overcome this drawback, the system under consideration may periodically allocate resources that each user attempts to occupy and attempt transmission of resources at the same time, and may use it to receive beam feedback of multiple users. When these resources are referred to as random access resources, these random access resources may be periodically allocated and each terminal may transmit uplink beam feedback through these resources. The advantage of this method is that it is not necessary to allocate the feedback resource to each terminal whenever the beam is changed between the terminal and the base station by using the changed beam, and since the beam to be used by the terminal exists in the abrupt beam state change, There is an advantage that the base station can be contacted.

13 is a diagram illustrating a beam-feedback procedure of a UE using a random access resource periodically allocated by a BS according to an embodiment of the present invention.

As described above, it is assumed that the BS periodically allocates a random access resource for transmitting feedback information to the MS.

In operation 1350, the beam-using subject 1310 may transmit a reference signal for beam measurement. The beam-using subject 1310 can transmit a beam-measuring reference signal for each of a plurality of beams.

In operation 1355, beam measurement subject 1320 measures the beam. The beam measurement subject 1310 can select the best beam based on the beam measurement result. The beam measuring method and the beam selecting method can use the beam measuring and beam selecting method already described.

In operation 1370, beam measurement subject 1310 may perform beam feedback. The beam feedback can be performed using a random access procedure. The beam measuring subject 1310 may perform feedback using the current best beam according to the beam measurement result. The beam measurement subject can send feedback in 1371 operation and receive a response to the feedback in 1372 operation. If the 1372 operation fails to receive a response to the feedback, it may again send feedback in 1373 operation and receive a response to the feedback in 1374 operation. The transmission and response procedure of the feedback information using the random access procedure is a new procedure and can be performed a plurality of times until a response is received from the beam using subject 1320. [

The random access resource is a base station beam sweep reception interval, and there is a waste due to a large amount of resource occupation required to receive the same information, and a collision may occur between transmission information of the terminals.

The random access scheme under consideration in the embodiment of the present invention may be a contention-based RACH and a contention-free RACH used in LTE, or may be a contention- It may be any method in which the terminal performs reception in a state in which the terminal may attempt to transmit and attempts to transmit the terminal using any predetermined or previously promised sequence in such a period.

14 is a diagram illustrating a procedure for considering a response request in feedback using periodic random access resources according to an embodiment of the present invention.

As described above, it is assumed that the BS periodically allocates a random access resource for transmitting feedback information to the MS.

Operations 1450 through 1474 refer to operations 1350 through 1374 of FIG.

In operation 1480, the beam measurement subject 1410 determines whether a response to the feedback has been received. The beam measurement subject 1410 confirms whether or not a response to feedback is received for a predetermined time. When receiving the response to the feedback, it can be confirmed that the beam-using subject 1420 has received information on the beam fed back by the beam-measuring subject 1410. If it is determined that the response to the feedback is not received, the operation 1485 can be performed.

If the condition that the response request is not received for a predetermined time is satisfied even though the UE has tried feedback transmission using the random access several times, the UE determines that the current beam status is no longer suitable for the uplink communication, And a reconnection procedure to the network using the new beam.

The condition that the response request is not received for a certain time is as follows:

- If the Random Access Response (RAR) message, which is a response to one Random Access Preamble transmission, is not received within a certain time

- If the Random Access Response (RAR) message, which is a response to the predetermined number of Random Access Preamble transmissions, has not been received within a certain time

- Random Access Response (RAR) message, which is a response to a Random Access Preamble transmission (including retransmission) attempted for a predetermined period of time, has never been received

At this time, if it is determined that the uplink feedback transmission is not performed through the feedback resource allocated for the predetermined time, the link failure can be declared to the corresponding terminal.

- The network can retain the information of the terminal that declared the link failure for a certain period of time and can quickly support reconnection using the other beam of the terminal.

- The network disconnects the terminal that has declared the link failure (discards the terminal information) and can follow the existing reconnection procedure when the terminal attempts to reconnect.

In operation 1485, the beam measurement subject 1410 may declare a link failure and attempt to reconnect to the network with a new beam. At this time, the beam attempting to reconnect to the network may be the best beam identified in operation 1455. For the connection failure, the contents described in Fig. 12 can be referred to.

2. 2. aperiodic feedback transmission method

After the resource allocatable entity (base station) has decided to receive feedback at some time based on a certain criterion, the resource can be allocated and the measurement subject (terminal) can transmit the feedback using the resource. The conditions and methods for this are as follows.

The beam feedback may be transmitted through an uplink control channel (eg, PUCCH) or an uplink data channel (eg, PUSCH), and may include a base station beam ID, a beam pair ID, a reception beam ID, RSRQ, SNR, SINR, RSSI, CQI, PMI, RI, and the like.

The uplink resource for beam feedback may be a resource that can be transmitted / received using a serving beam currently being used by a corresponding base station. Or may be a resource capable of transmitting / receiving using any beam that can be received when the base station determines, or may be a resource that is capable of sweeping and receiving multiple beams that allow the base station to cycle through the available beams. It may be a resource in the interval.

The resource for the aperiodic feedback allocated by the base station can be allocated to the base station so as to be able to receive the best one or more beams used by a terminal known at the current scheduling time. At this time, the base station may transmit the beam information to be received by the resource to the mobile station in the form of the base station beam ID in the scheduling information.

An example of a criteria by which a resource assignable entity determines aperiodic feedback is as follows:

- If new feedback is not received during a certain time elapsed from the previous feedback reception time (resource allocation when timer expires by timer)

- If no information is received from the terminal during the lapse of a certain time (resource allocation when timer expires by timer)

- If the measurement result of link, channel status (quality, power, SNR, SINR, CQI, RSRP, RSRQ, ...) is below a certain threshold

- The measurement result of the connection (link, channel) state (quality, power, SNR, SINR, CQI, RSRP, RSRQ, ...) If the value falls below the threshold

After the measurement subject (terminal) decides to transmit the feedback based on a certain criterion at a certain time, feedback is performed by a method such as a resource allocation request (scheduling request) or a random access procedure or the like, Examples of conditions and methods of transmission are as follows: - If resources are not allocated to transmit new feedback during a certain time elapsed from the previous feedback reception time (resource allocation when timer expires by timer)

- If no information is received from the base station during a certain time (resource allocation when timer expires by timer)

- If the measurement result of link, channel state (quality, power, SNR, SINR, CQI, RSRP, RSRQ, ...) with the corresponding base station is below a certain threshold

- The quality of the link, channel status (SNR, SINR, CQI, RSRP, RSRQ, ...) with the corresponding base station is higher than the previous (or previous, If the value falls below the threshold

There may be a terminal-initiated feedback transmission method by any event proposed in the feedback method other than the above-mentioned example.

The UE using the beam can feedback the beam information using the corresponding resource when the UE has periodic beam feedback resources allocated by the BS. It is also possible that the UE determines the necessity of beam feedback transmission, Information can be transmitted to the base station.

In this case, the operation of the UE considering whether existing resources exist or not exists is as follows.

15 is a diagram illustrating a feedback method of a UE according to whether an allocated resource exists according to an embodiment of the present invention.

Referring to FIG. 15, in operation 1510, the terminal measures the beam. The terminal may receive a beam measurement reference signal (BRS) transmitted by the base station and measure and measure it for different receive beams to obtain a beam quality measurement value for each base station transmit beam and terminal receive beam pair.

In operation 1520, the terminal may select a preferred beam. The selected beam may be a best beam. The terminal may compare the beam quality measurements to each other and select the best terminal receive beam for each base station transmit beam. In addition, the terminal can select a preferred beam (or beam group) by dividing the beam (or beam group) that the base station may transmit in the order of the transmission beams having the best quality.

In operation 1530, the terminal may determine whether it is necessary to change the beam currently in use to another beam. As a concrete method for determining the necessity of beam change, refer to the beam change determination method described in FIG. 9 and the like.

If it is determined that there is no need to change the beam, operation 1550 is performed. In 1550 operation, the terminal can feed back the existing beam. The existing beam may be the beam currently in use. Since there is no need to change for the beam currently in use, the beam currently in use may be the current best beam. 1550 operation may be omitted if it is determined in the 1530 operation that there is no need for a beam change.

If it is determined that there is a need to change the beam, operation 1560 can be performed. In operation 1560, the terminal may determine whether a pre-allocated feedback resource is available.

Proceed to operation 1565 if the use of pre-allocated feedback resources is possible. In operation 1565, the UE can feedback using pre-allocated feedback resources. The feedback may include information about the beam to be changed. For specific feedback information, see the discussion in the Feedback Related Information section.

If it is not possible to use the pre-allocated feedback resources, the process can proceed to 1570. In operation 1570, the UE can feedback information about the beam to be changed by utilizing the beam change reception period of the base station. The feedback information for the beam may include a beam change request. The beam change request may be explicit information. It may also implicitly indicate a beam change request when the beam being fed back through the beam feedback information is different from the beam in use.

The terminal operation transmits the beam feedback using the resource when the terminal that needs to change the use beam is exclusively allocated with the uplink feedback resource for the terminal through the beam known to the base station from the base station A case in which it is judged once again whether or not it is judged.

The conditions for determining whether the use beam change is required by the terminal may be conditions for determining whether the beam change described in the previous embodiments is necessary or not.

As described above, according to the embodiment of the present invention, the terminal can perform a beam feedback operation to provide the beam measurement information to the base station according to the determination of the terminal according to the resource allocation of the base station. Various specific embodiments will be described in more detail below. In order to feedback the beam measurement information according to the determination of the UE, the UE needs to allocate to the UE a resource capable of transmitting scheduling request information to the BS.

However, if these resources are not allocated or these resources are unavailable (for example, the beam quality in use is suddenly deteriorated, the uplink synchronization of the terminal is out of order, or the like) may occur. Considering this possibility, in order to maintain the wireless connectivity of the terminal by providing the beam measurement information of the terminal to the base station and using the available beam if there is such a beam, it is necessary to transmit any terminal or information to the base station Any shared resources that can be needed.

In both of the periodic beam feedback method and the aperiodic beam feedback method, resource allocation of the base station is required for uplink feedback transmission of the UE. To this end, the base station may set a period or a time period during which the beam feedback should be performed at least once.

The established period or time interval may be known to each mobile station by the base station, and the known method may be one of the following message transmission methods:

- An element that specifies the beam feedback duration in the RRC message,

- Including an element that specifies the beam feedback duration in the Downlink Control message (via PDCCH)

- The downlink MAC-CE message (via PDSCH) including an element that specifies the beam feedback duration.

- In addition to any other means that may include an element that specifies the beam feedback duration,

The candidates for the configurable period or time interval are as follows:

- Full beam sweep duration: The time required for the terminal to observe all the beam pairs of the base station and the terminal

- 5G NB Tx Beam Sweep duration: The time required for the terminal to observe all base station beam pairs for one terminal beam

- Every Beam Reference Signal measurement duration: The minimum beam observation period (eg Beam Reference Signal subframe transmission time interval)

- Any other specific time interval

3. Shared resource design that base station can receive for UE-initiated uplink beam feedback

In order for the UE to transmit uplink information without allocating resources from the base station, a shared resource interval is set so that the base station can transmit all the resources. In a conventional wireless communication system, a random access channel (RACH) in which an initial access terminal transmits its own information in order to transmit a network access request to a base station is an example of such a shared resource period.

In the case of a multi-antenna beamforming system in which resources such as frequency channel, time, beam, and code are allocated differently for different beams, the setting and design of such a shared resource section should be made more sophisticated. The beam pairs that the terminal and the base station can successfully transmit / receive information are limited. Since the base station does not know when a terminal transmits information, the base station can transmit information such that all terminals can transmit information, The resource section should be designed to receive all beams.

Therefore, the base station should be designed to sequentially receive and receive the shared resource period by sweeping the beam received by the base station, and notify this period to an arbitrary terminal through broadcasting or the like.

When the base station allocates any shared resource section for receiving information from an unspecified arbitrary terminal while sweeping the receiving beam, the terminal can successfully transmit the uplink signal using the base station beam measurement information and the spontaneous determination, Beam feedback can be transmitted. At this time, since the beam feedback information can be transmitted / received by any beam other than the beam used for communicating with the base station in advance, the probability of success of the transmission is allocated through the resource allocated by the base station It is expected that it will be significantly larger than when it is transmitted using the used beam.

The shared resource period allocated by the BS may be allocated to a beam used for a purpose other than a beam used for exchanging data between the BS and the MS (e.g., control information transmission). In this case, the shared resource period may be allocated to use a beam having a width different from the width of the beam used for exchanging data between the base station and the terminal (using a control beam having a wide beam width) have.

Also, the shared resource period allocated by the BS is not a multi-antenna using beamforming in which different resources such as a frequency channel, a time, a beam and a code are allocated and used differently for different beams used for exchanging data between the BS and the UE , Or a channel using any omni beam. In addition, such a channel may be defined and exist so as to be usable between a base station and a terminal.

The characteristics of the above-described base station beam swing sharing reception section are as follows.

- Base Station Beam Swapping The shared reception interval may be any resource that can be transmitted by a specific terminal or a group of terminals allocated for a specific terminal.

- The base station beam sweep sharing period may be any resource that can be transmitted by an unspecified number of terminals allocated for an unspecified number of terminals.

- Base Station Beam Sweeping Sharing reception interval is a time interval in which a certain frequency (frequency, subframe number, resource block number, channel number, etc.), time (time, frame number, subframe number, Sub-frame / slot, etc.), beam resource information, and the like.

- The terminal and the base station know that the information on the corresponding base station beam sweep sharing section is always known to the standard and are always present in a specific frame position, so that there is no need for a special known signal transmission, May be included in any network information (e.g., MIB, SIB, etc.) known as a broadcasting channel, or may be included in any network information dl (unicast) announcement to each terminal using a downlink control channel (PDCCH) scheduling information).

- The terminal obtains information on the base station beam sweep sharing period and includes a beam change request to change the used beam using the corresponding resource (may explicitly include any bit or array, The operation of transmitting the request itself may be implicitly recognized as a beam change request).

- The base station can receive the beam feedback information of the terminal that intends to use the previously used beam and the changed beam by utilizing the base station beam swapping shared reception period.

- In the embodiment of the present invention, the above-mentioned and the above-mentioned beam feedback method using random access need not necessarily use the random access method used in other standards such as 3GPP standard or IEEE. Basically, the beam feedback method in the embodiment of the present invention collectively refers to a method and procedure for exchanging information between a terminal and a base station using a method in which a base station changes a beam and transmits feedback using a receiving section.

FIG. 16 is a diagram illustrating a method of constructing a base station beam sweeping shared reception interval and a preamble transmission method according to an embodiment of the present invention.

Referring to FIG. 16, the x-axis is the random access period and the y-axis is the frequency. The random access period may be divided into a plurality of time intervals. Rx eNB # 1, Rx eNB # 2, Rx eNB # 3, and Rx eNB last Beam # 4 represent the respective sections. The base station can receive the beam feedback information from the terminal while changing the beam whenever the interval is changed.

In the above example, it is assumed that the number of beams received by the base station during one Random Access period is one. In the above example, the number of beams received by the base station during the Random Access period may be one or more than one. In the above example, the beams received by the base station during different periods during the Random Access period may be the same. In the above example, the number of beams received by the base station during one period in the Random Access period may be one or more. In this case, the base station may receive the corresponding beams using different resources such as different frequencies and physical locations.

FIG. 17 is a diagram illustrating a method of constructing a base station beam sweeping shared reception interval and a preamble transmission method according to another embodiment of the present invention.

Referring to FIG. 17, the base station beam-modification sharing reception interval may be configured to receive different beams away from each other.

For example, section 1710 shows the reception section as blank. Thus, a space may be included between the section for the reception beam #K and the section for the reception beam # K + 1. In this case, a section for receiving the beam may be dropped. In the example of FIG. 17, a plurality of spaces may be set within one period.

FIG. 18 is a diagram illustrating a method for constructing a base station beam swing sharing reception interval and a preamble transmission method according to another embodiment of the present invention.

Referring to FIG. 18, there is shown an example of allocating different resources (e.g., frequency) in a beam region to be received for each user.

The configuration in which the section of the Rx beam is changed for each section of the time axis in FIG. 18 is the same as that described in FIG. In the embodiment of FIG. 18, not only the Rx beam is changed for each section of the time axis but also feedback information for different terminals on the frequency axis can be received. During the first time interval, it is possible to receive feedback information for UE # 1, UE # 2, ..., UE # M for each frequency through Rx beam # 1, UE # 1, UE # 2, ..., UE # M.

As in the above embodiment, the proposed system assigns a unique resource to all users (or a specific user), transmits the uplink information at a specific location, notifies each user thereof, and receives beam information through the corresponding resource have.

There are various ways of transmitting the allocation information of the resource, and it is possible to transmit any type of information including the frequency and time information of the allocated resource. For example, it may be transmitted in the form of DCI (Downlink control information) transmitted using the 3GPP LTE PDCCH. Here, the (Rx) beam received by the eNB is a beam having N different directivity analog beamforming Or may be a beam having a digital beamforming form which is received at the same time but is encoded in different coding, or may be a hybrid beam using an analog beam and a digital beam in combination, and the omni It may be a beam.

Herein, the feedback best beam information may be information on multiple beams more than information on one beam.

If there is no beam feedback and beam change request method using this base station beam swapping shared reception interval, even if a previously used beam is no longer available, even if there is a new communicable beam, It is necessary to wait until the condition of the radio link failure (RLF) is satisfied and to perform a new initial access procedure to reconnect the network with the new network.

In a very high frequency band such as mmWave having a strong directivity, a wireless link may generate various obstacles due to passing vehicles, user movement, etc., and frequent beam changes may occur within a very short time (for example, within 50 ms).

In the case where the position of the UE has not changed greatly and another beam pair capable of communicating with the corresponding (connected) base station exists, it is a waste of time to perform such conventional determination of the failure of the network link and reconnection.

Therefore, the embodiment of the present invention proposes a method of transmitting a beam change request according to the beam change and beam status measurement as described above, faster and more reliably than the existing network link failure using the beam change reception period of the base station .

Considering a more realistic and practical implementation from now on, it may be possible to 1) a beam feedback method using resources allocated by a base station, 2) a terminal-driven uplink beam feedback method, and 3) 4) The present invention will be described with reference to the following embodiments in consideration of all environments which may be aperiodic.

FIG. 19 is a diagram illustrating a feedback method considering both a beam-based method using a resource allocated by a base station and a UL-directed UL feedback method according to an embodiment of the present invention.

Referring to FIG. 19, the beam measurement subject 1910 may be a terminal and the beam usage subject 1920 may be a base station. In operation 1940, the beam-using subject 1920 may assign a feedback resource to the beam-measuring subject 1910. The feedback resource may be a dedicated feedback resource. The feedback resources may be periodically allocated, and may be non-periodically allocated. In operation 1945, the beam-using subject 1920 may send information about the allocated feedback resource to the beam-measuring subject 1910. 1940 operation and 1945 operation may be collectively referred to as a feedback resource allocation process. The beam using subject 1920 can transmit information on the feedback resource to the beam measuring subject 1910 using the currently used best beam.

In operation 1950, the beam-using subject 1910 may transmit a reference signal for beam measurement. The beam-using subject 1910 can transmit a reference signal for beam measurement for each of a plurality of beams.

In operation 1955, beam measuring subject 1910 measures the beam. The beam measurement subject 1910 can select the best beam based on the beam measurement result. The beam measuring method and the beam selecting method can use the beam measuring and beam selecting method already described in the previous embodiments.

In operation 1960, the beam measuring subject 1910 may transmit the beam measurement results to the beam using subject 1920. The beam measurement result may include the contents of the feedback resource described in the above embodiments.

In operation 1965, the beam measurement subject 1910 determines whether or not the terminal-driven beam-feedback transmission condition is satisfied. The terminal-driven beam feedback means an operation of determining the necessity of beam feedback directly and transmitting the beam feedback instead of the periodic feedback transmission request of the base station. If terminal driven beam feedback is not required, the beam measurement subject 1910 ends the beam feedback operation.

If the terminal-driven beam-feedback operation is required, the operation proceeds to operation 1970. In the 1970 operation, the beam measurement subject performs beam feedback using the base station shared reception interval. The base station shared reception period refers to the contents described in Figs. 16 to 18. The beam measurement subject 1910 may receive information on the base station shared reception period from the beam usage subject 1920 in advance. The beam measurement subject 1910 can transmit feedback information using the time resource and the frequency resource of the base station shared reception interval.

In operation in the 1970, the beam measuring subject 1910 can perform beam feedback. The beam measuring subject 1910 can perform feedback using the current best beam according to the beam measurement result. The beam measurer may send feedback in 1971 operation and receive a response to the feedback in 1972 operation. If it does not receive a response to the feedback in the 1972 operation, it can send back the feedback in 1973 operation and receive the response to the feedback in the 1974 operation. The transmission and response procedures of the feedback information may be performed a plurality of times until a response is received from the beam using subject 1920.

In operation 1975, the beam-using subject 1920 may modify the beam information of the terminal or change the beam to the terminal, if necessary, based on the received beam-feedback information.

In the embodiment of FIG. 19, the order of the dedicated feedback resource allocation operation for beam feedback in the terminal operation and the sequence of operations for measuring the reference beam for beam measurement and selecting the best beam may be reversed.

In the UE operation, the UE should try to transmit beam feedback as requested by the base station through the resources allocated by the base station. Such beam-feedback transmission resources may be allocated periodically or non-periodically by the base station.

Alternatively, the UE may transmit beam-feedback using the shared reception interval allocated by the BS.

The UE-driven beam-feedback transmission condition may use at least one of the feedback conditions described in the previous embodiments.

In this embodiment, the UE may transmit beam feedback using dedicated resources allocated by the existing BS if necessary, and may transmit the same beam feedback information using the shared reception period of the BS when the condition is satisfied. In this case, the beam feedback transmitted using the dedicated resources allocated by the base station and the beam feedback transmitted using the base station shared reception period may be transmitted / received using different terminal beams and / or base station beams.

In the above embodiment, the beam-feedback resource allocation of the base station is determined as periodic resource allocation, the terminal-driven beam-feedback transmission condition is set when the best beam is changed to another beam, and when the shared reception period of the base station is defined as the Random Access reception period, &Lt; RTI ID = 0.0 &gt; 20. &Lt; / RTI &gt;

20 is a diagram illustrating a beam feedback method using resources allocated by a base station according to another embodiment of the present invention and a feedback method considering a terminal-initiated uplink beam feedback method.

Referring to FIG. 20, the beam measurement subject 2010 may be a terminal and the beam usage subject 2020 may be a base station.

2040 to 2060 operations refer to operations 1940 to 1960 of FIG. In the 2045 operation, the feedback resource allocation may be a periodic dedicated feedback resource allocation.

In operation 2065, the beam measurement subject 2010 can determine whether a change of the best beam is necessary. The conditions for determining whether the beam change is necessary refer to the description of the beam change in the previous embodiment.

If it is determined that the beam change is not necessary, the procedure can be terminated without performing terminal-driven beam feedback. If it is determined that beam change is necessary, operation 2070 can be performed.

In operation 2070, the beam measuring subject 2010 can perform beam feedback. The beam feedback can be performed using a random access procedure. The beam measuring subject 2010 can perform feedback using the current best beam according to the beam measurement result. The beam measurement subject may transmit feedback in 2071 operation and receive a response to the feedback in 2072 operation. If the 2072 operation fails to receive a response to the feedback, it may again send feedback in 2073 operation and receive a response to the feedback in 2074 operation. The transmission and response procedure of the feedback information using the random access procedure is a new procedure and can be performed a plurality of times until a response is received from the beam using subject 2020. [

In operation 2075, the beam-using subject 2020 can allocate periodic dedicated feedback resources using the recognized best beam.

FIG. 21 is a diagram illustrating a feedback procedure in the case where the UE-initiated beam-feedback performance precedes the feedback resource allocated by the base station in another embodiment of the present invention.

Referring to FIG. 21, the beam measurement subject 2010 may be a terminal and the beam usage subject 2020 may be a base station.

2140 to 2155 operations refer to operations 1940 to 1955 of FIG. In operation 2165, the beam measurement subject 2110 may determine whether a change in the best beam is necessary. The conditions for determining whether the beam change is necessary refer to the description of the beam change in the previous embodiment.

In operation 2170, beam measurement subject 2110 performs beam feedback using the modified beam. A specific method refers to operation 2070 of FIG.

In the 2185 operation, the beam usage subject allocates a periodic dedicated feedback resource with the perceived best beam.

22 is a diagram illustrating a process of using a different bandwidth in terminal-initiated feedback transmission according to another embodiment of the present invention.

Referring to FIG. 22, the UE-initiated beam-feedback transmission may be transmitted / received using a beam having a different width from a beam used for information transmission, for example, an omni beam or a wide / narrower beam . The beam measuring subject 2210 may be a terminal, and the beam using subject 2220 may be a base station.

The operations 2240 to 2275 of FIG. 22 refer to the contents of operations 2240 to 2075 of FIG. In operation 2270, the beam measuring subject 2210 may transmit feedback to a beam of a different width than the beam used by the base station for information transmission, and the beam using subject 2220 may transmit a beam of a different width It is possible to receive the feedback information of the beam measuring subject 2210 with the beam.

In the 2270 operation, the base station can operate a section for receiving wireless information using an Omni or Wide beam for a terminal whose beam direction is distorted or the base station does not know what beam should be received.

In this interval, the UE may transmit the information to the BS using random access. 2. The BS may transmit the information to the BS using the resources always allocated to the UE.

Feedback transmission using the dedicated dedicated feedback resource may be performed irrespective of whether the best beam is changed or not, and feedback transmission may not be performed by determining whether the best beam is changed.

23 is a diagram illustrating a feedback procedure according to whether or not a terminal-driven beam-feedback transmission condition is satisfied according to another embodiment of the present invention. In the embodiment of FIG. 23, each beam-measuring subject 2310 may review the condition before each feedback and may choose how to send the feedback according to the condition.

23, the beam measuring subject 2310 may be a terminal, and the beam using subject 2320 may be a base station. 2340 operation to 2365 operation refer to the description of operations 1940 to 1965 in FIG.

In operation 2365, if it is determined that the terminal-driven beam-feedback transmission condition is satisfied, the operation proceeds to 2370. In operation 2370, the beam measurement subject 2310 performs beam feedback using the base station shared reception interval. The concrete operation refers to the description of the base station shared reception interval and the operation of 1970. [ 2371 through 2374 operations refer to the 1971 through 1974 operations of FIG.

In operation 2375, the beam-using subject 2320 may modify the beam information of the terminal or change the beam to the terminal, if necessary, based on the received beam-feedback information.

If it is determined that the terminal-driven beam-feedback transmission condition is not satisfied in operation 2365, the operation can proceed to 2380 operation. The beam measurement subject 2310 may transmit feedback information using the dedicated dedicated feedback resource.

The UE may transmit the beam feedback information using the assigned dedicated feedback resource or the BS shared reception interval, and may transmit the beam feedback information using the shared reception interval at the time of every beam measurement, Alternatively, you can choose whether to send feedback using the dedicated feedback resources that are assigned. In this case, the beam feedback transmitted using the dedicated resources allocated by the base station and the beam feedback transmitted using the base station shared reception period may be transmitted / received using different terminal beams and / or base station beams.

FIG. 24 is a diagram illustrating a terminal operation when a beam-based feedback method using a shared reception interval of a base station is a contention-based random access method in the embodiment of FIG. Here, the contention-based random access method is constructed by referring to 3GPP LTE RACH (Random Access Channel Usage Operation).

Referring to FIG. 24, the beam measuring subject 2410 may be a terminal, and the beam using subject 2420 may be a base station.

2440 to 2465 operations of FIG. 24 refer to the description of operations 2340 to 2365 of FIG. If it is determined that the terminal-driven beam-feedback transmission condition is satisfied in operation 2465, the operation proceeds to operation 2470. In operation 2470, the beam measurement subject 2410 may begin the beam feedback operation using the modified beam. The beam measuring subject 2410 may start beam feedback using a random access procedure.

In operation 2372, the beam measurement subject 2410 may select a random access preamble sequence and transmit a random access preamble using the selected random access preamble sequence. At this time, the beam measurement subject 2410 can transmit the random access preamble using the beam to be changed. A terminal that has decided to transmit the beam-driven beam-feedback using a base station shared interval (here, a random access channel) randomly selects one of the known preamble sequences (known to be available to the base station) And transmits the random access preamble using one random access channel.

If the BS allocates a period for receiving the random access preamble by sweeping the beam, the UE may 1) transmit a preamble for all the BS receive beams within the corresponding interval, and 2) May transmit a preamble to one (or N) base station receive beams that are most likely to be successfully received.

In operation 2474, the beam-using subject 2420 receives a random access preamble. In addition, the beam using subject 2474 judges whether or not to transmit a response to the changed beam to the beam measuring subject 2410 based on the received random access preamble. The beam using subject 2420 can determine whether the beam transmitted the random access preamble is a best beam or a modified beam that has been used before and can determine that the best beam should be changed if the beam is a changed beam. The base station may change the beam and determine which terminal selected which preamble has succeeded / failed in the transmission of the uplink preamble through the PRACH that receives the random access preamble. At this time, the beam (or beams) successfully received is used to select the beam that has received the preamble as a beam to be used for wireless communication with the terminal. At this time, the base station does not yet know which terminal has transmitted a preamble for which purpose.

The preamble transmission using the existing contention-based random access is used for 1) initialization / re-connection of the network or 2) uplink synchronization acquisition of the UE, but in the embodiment of the present invention, Lt; RTI ID = 0.0 &gt; initiation &lt; / RTI &gt;

In operation 2476, the beam-using subject 2420 transmits a random access response. The beam using subject 2420 can transmit a random access response through the changed beam when beam change is required based on the received random access preamble. The random access response may include information for uplink resource allocation. The base station refers to the preamble transmitting terminal as RA-RNTI (Random Access Radio Network Temporary Iendtifier) based on the transmission / reception time of each preamble. The BS selects a beam that receives the preamble, allocates UL resources to the beam, and generates a Random Access Response (RAR) message to generate a RAR window ) To the terminal using the corresponding beam. Assuming channel symmetry (Reciprocity), the best beam that the terminal should transmit is the same beam as the best beam that the base station may transmit.

In 2478 operation, the beam measurement information can transmit channel information. The channel measurement information may include information on CSI (channel state information) and CQI (channel quality indicator). The terminals that have selected different random access sequences can distinguish whether the information transmitted by itself is received or not and the RAR is transmitted to itself by looking at the information contained in the RAR. (Determine whether RAR including RA-RNTI has been transmitted according to the time that it sent.)

The terminal having opened the RAR received in its own RA-RNTI judges that the corresponding RAR is the RAR for the preamble transmitted by itself if the preamble ID in the corresponding RAR coincides with the preamble ID transmitted by itself, .

1) The TC-RNTI included in the RAR is determined as the ID to be used in the next uplink message transmission

2) Utilization of Timing Advance information in RAR

3) Identify the uplink transmission resources of the next message by grasping the UL Grant in the RAR

The UE transmits (feeds) the UE information, the channel information, the best beam information, and the like in accordance with the UL resource scheduling information (UL Grant) included in the received random access response. At this time, the UE selects TC-RNTI, which is the transmission of feedback information, and transmits an ID (if any) indicating that the corresponding message is an uplink beam feedback message.

In a 2480 operation, a BS receiving a corresponding message can know that the corresponding message is uplink beam feedback information from a specific MS as follows:

1) The UE uses UL Grant, transmits C-RNTI information including C-RNTI information used in the uplink message, and the BS can use it to inform that the UE is already connected.

25 is a diagram illustrating a frame structure of beam feedback transmitted by a UE according to an embodiment of the present invention. Referring to FIG. 25, a beam-feedback frame may include a TC-RNTI, a C-RNTI, and beam feedback information. The beam-feedback frame includes a TC-RNTI as an ID of the corresponding message sender, and includes any ID (C-RNTI) indicating that the sender of the corresponding message is disconnected in the message (C-RNTI) (Beam ID, beam reception position, beam channel performance, etc.) to be changed. The Beam Feedback Information may be one of values that can be observed and calculated by the UE, such as RSRP, RSRQ, CQI, SNR, SINR, and RSSI.

2) The UE can update the beam information of the corresponding UE by including the information indicating that the corresponding message is the UL Beam Feedback in the UL Grant Uplink message.

26 is a diagram illustrating a frame structure of beam feedback transmitted by a UE according to another embodiment of the present invention. Referring to FIG. 26, the beam-feedback frame may include a TC-RNTI, a category, a C-RNTI, and beam feedback information. In FIG. 26, the category may include information indicating that the corresponding message is information for beam feedback.

Upon receiving the beam feedback message as in the above 1) or 2), the base station recognizes that the transmitting end of the corresponding message is a specific terminal that has been connected (using the C-RNTI), updates or corrects Information can be used).

In 2480 operation, beam-using subject 2420 may send a random access termination message. The random access may be contention-based random access, and the random access termination message may include contention-based random access results. After receiving the terminal information transmitted to the UL Grant resource, the base station can transmit a reception acknowledgment message to the terminal and can resolve the random access collision of the terminals that selected the same preamble.

In operation 2490, the beam-using subject 2420 may modify the beam information of the terminal or change the beam to the terminal, if necessary, based on the received beam-feedback information.

If the terminal-initiated beam-feedback transmission condition is not satisfied in operation 2465, then operation 2485 may proceed. In operation 2485, the beam measurement subject 2410 may transmit feedback information using the dedicated dedicated feedback resource.

In the above flowchart, the proposed technique can support transmission of beam-feedback every third uplink information transmission differently from 3GPP RACH. That is, in the conventional random access procedure, the process of transmitting the beam feedback through the third uplink information transmission is not included. However, in order to transmit the beam feedback information using the random access procedure in the embodiment of the present invention, And transmits the additional information about the beam feedback. In order to do this, the BS allocates resources for transmission of the third uplink information in response to the RACH procedure requested by a UE by transmitting a random access preamble, and allocates a size Of resources.

FIG. 27 is a diagram illustrating a terminal operation when the beam-feedback method using the shared reception interval of the base station in the embodiment of FIG. 23 is a non-contention-based random access method. Here, the non-contention-based random access method is constructed by referring to the 3GPP LTE RACH (Random Access Channel Usage Operation).

23, the beam measuring subject 2710 may be a terminal and the beam using subject 2720 may be a base station. 2740 Operation 2765 Operation of FIG. 27 refers to the description of operations 2340 through 2365 of FIG.

Since the embodiment of FIG. 27 is characterized by beam feedback with an uncompensated random access, the beam using subject 2720 in 2747 operation can allocate a dedicated random access preamble. The random access preamble may be assigned to each terminal to be unique. The random access preamble may be assigned with a unique value so that each terminal can be used only for requesting resource allocation for beam feedback transmission. The random access preamble can be assigned with a unique value to be used for various purposes such as the use of each terminal requesting resource allocation for some uplink transmission and the request for resource allocation for beam feedback transmission .

In operation 2665, if the terminal-driven beam-feedback transmission condition is satisfied, operation 2770 is performed. In operation 2770, the beam measuring subject 2710 may begin the beam feedback operation using the modified beam. The beam measuring subject 2710 may start beam feedback using a random access procedure.

In operation 2772, the beam measurement subject 2410 can transmit a random access preamble using a predetermined random access preamble. The beam measurement subject 2710 can transmit the random access preamble using the random access preamble received in the 2747 operation. In order to perform the non-contention-based random access, the UE transmits a random access preamble, which is a UE-specific random access preamble allocated in advance by the base station, to the base station using the RACH channel.

In operation 2774, the beam user 2720 can specify a terminal that transmitted a random access preamble based on the received random access preamble. The beam using subject 2720 can check and select a usable beam for the UE based on the received random access preamble. The base station receiving the preamble recognizes that there is beam feedback information to be transmitted by the mobile station, and can allocate as much beam feedback resources as necessary to the mobile station.

In 2776 operation, the beam-using subject 2720 may transmit a random access response using the modified beam if the beam has changed. The random access response may include resource allocation information for beam feedback.

In 2778 operation, beam measurement subject 2710 may transmit beam feedback information to the assigned resource.

In operation 2790, the beam using subject 2720 may modify the terminal beam information based on the received beam feedback information. In addition, the beam-using subject 2720 can perform the beam changing procedure with the beam-measuring subject 2710, if necessary.

2765 operation, it is possible to transmit the beam feedback using the allocated power feedback resource.

In this embodiment, the beam-feedback resource allocation of the base station is determined to be a periodic resource allocation, the terminal-driven beam-feedback transmission condition is changed to another beam of the best beam, the previous beam is determined to be unusable, It can be explained by the embodiment as shown in Fig. 28 below.

28 is a diagram illustrating a beam measurement and a beam feedback operation of a UE using a random access procedure according to an embodiment of the present invention.

28, the beam measuring subject 2810 may be a terminal, and the beam using subject 2820 may be a base station. The operations 2840 to 2855 of FIG. 28 refer to the description of operations 2740 to 2755 of FIG.

In operation 2865, the beam measuring subject 2810 determines whether a best beam change is necessary and the use of the previous best beam is not possible. Where the previous best beam availability may be when the channel state of the previous best beam (currently used beam) is observed to be below a certain threshold value. Herein, the previous best beam utilization possibility is calculated as follows: when the best beam measured by the terminal is changed in the existing best beam and the previous best beam channel state is lower than a certain threshold (another beam> current beam + Threshold_1) or / )). &Lt; / RTI &gt; The channel state may be one of RSRP, RSRQ, CQI, SNR, SINR, PER, BER, BLER, FER.

If it is not necessary to change the best beam, the process proceeds to 2885 operation to transmit feedback information. In operation 2885, the beam measurement subject 2810 may transmit feedback information using the dedicated dedicated feedback resource.

If it is determined that a best beam change is required in operation 2865, the operation proceeds to 2870 operation. In operation 2870-2874, beam measuring subject 2810 may perform beam feedback using the modified beam. At this time, a random access procedure can be used. The process of using the random access procedure may use the feedback procedure using the random access described in FIGS. 23, 24, 27, and the like.

In operation 2880, the beam-using subject 2820 may allocate dedicated feedback resources to the perceived best-beam. Resource allocation can be performed periodically. The beam using subject 2820 can recognize the best beam from the beam feedback.

3. 1. User-initiated beam feedback transmission method according to uplink synchronization

A. When the uplink synchronization is correct (timeAlignmentTimer, (TAT) has not expired or any condition is satisfied), any base station capable of transmitting a preamble having a short cyclic prefix (CP) length according to uplink synchronization A resource for beam feedback is requested through an uplink transmission using a preamble in a period during which a beam is swept and received, and beam feedback can be transmitted when resources are allocated.

a1. At this time, the terminal may request the base station to change the beam to the corresponding beam by transmitting the preamble when the base station receives the specific beam (the terminal desires to change the beam) within the interval in which the base station sweeps the beam . In this case, the base station may directly change the beam in response to the resource allocation, or may transmit a signal instructing the beam change without allocating resources.

a2. In this case, if the period for transmitting the preamble for beam change is a Scheduling Request (SR) transmission period, beam feedback may be transmitted to the UL grant resource of the SR,

a3. If a beam change is required, the base station may send a beam change indication in response to the beam feedback.

B. Or, if a preamble having a short cyclic prefix length is not received from the base station even if the uplink synchronization does not match or the uplink synchronization is right, a preamble selected arbitrarily based on the contention may be used, The base station may transmit the beam resource by requesting the uplink resource by transmitting the preamble using a preamble to the base station by sweeping the beam and transmitting the beam resource by allocating the uplink resource.

b1. At this time, the terminal may request the base station to change the beam to the corresponding beam by transmitting the preamble when the base station receives the specific beam (the terminal desires to change the beam) within the interval in which the base station sweeps the beam . In this case, the base station may directly change the beam in response to the resource allocation, or may transmit a signal instructing the beam change without allocating resources.

b2. At this time, if the interval for transmitting the preamble for beam change is RACH, the RACH msg. 3 with beam feedback,

b3. If a beam change is required, the msg. 4 contention resolution including a beam change indication.

C. Alternatively, regardless of the uplink synchronization, the base station transmits a resource allocation request message, a beam feedback transmission message, or a beam change request message to the base station in a certain period during which the base station changes its beam (sweeping) It is possible to inform that the beam change of the terminal is necessary.

c1. In this case, the mobile station can transmit any pre-determined signal that can be received by the base station, and the signal can be transmitted using a very short signal (short preamble / beacon / reference signal / pilot signal).

c2. The base station receiving the signal may perform an operation to detect that the corresponding signal is transmitted from a specific terminal, and may perform an operation for changing the scheduling beam of the terminal.

D. Alternatively, beam feedback may be transmitted in the form of piggyback (MAC-CE) or multiplexing (UCI) to the uplink data in the resource for the pre-allocated uplink transmission.

E. The beam feedback method need not be limited to the RACH, but can be transmitted in any period in which the base station sweeps and receives the beam.

In yet another embodiment, If the difference between the current time and the reference signal transmission time for beam measurement is below a certain threshold value, a base station operation that does not allocate feedback resources may be added.

FIG. 29 is a diagram illustrating a feedback method according to a feedback resource allocation using a time threshold according to an embodiment of the present invention. Referring to FIG.

29, the beam measuring subject 2910 may be a terminal, and the beam using subject 2920 may be a base station. 2930 operation, the difference between the current time and the time at which the reference signal for beam measurement is transmitted can be compared with the threshold value. If the difference is less than or equal to the threshold value, the feedback resource is not allocated. If the difference is not less than the threshold value, proceed to operation 2940 and allocate a feedback resource. Here, the beam measurement and the periodic dedicated feedback resource allocation may be performed in different orders.

The operations 2940 to 2955 refer to the description of operations 2840 to 2855 of FIG. In operation 2965, the beam measurement subject 2910 may determine whether it meets the conditions for transmitting the feedback information using the random access procedure. 2965 The conditions of operation may be at least one of various conditions for the terminal-driven feedback method mentioned above.

If the feedback condition using the random access procedure is not satisfied, the operation proceeds to the 2980 operation, and the feedback information can be transmitted using the dedicated dedicated feedback resource.

If the feedback condition using the random access procedure is satisfied, the operation proceeds to operation 2970 to perform beam feedback. The beam feedback can be performed using the selected current best beam. Operations 2970 through 2974 correspond to operations 2870 through 2874 of FIG.

In another embodiment, there may be an example in which the terminal ignores the dedicated feedback resource allocated to the UE within a specific time before the beam measurement and before the feedback transmission.

30 is a diagram illustrating a procedure for transmitting feedback using dedicated feedback resources or random access according to a specific time according to an embodiment of the present invention.

Referring to FIG. 30, the beam measurement subject 3010 may be a terminal and the beam usage subject 3020 may be a base station.

In operation 3025, the beam-using subject 3020 may allocate resources for beam-feedback. The resources for beam feedback may be periodic dedicated feedback resources. The beam using subject 3020 can allocate resources using the already known best beam.

In operation 3030, the beam measuring subject 3010 may compare the difference between the current time and the reference signal reception time for beam measurement to a predetermined threshold value. If the difference is not less than the threshold value, the feedback information is transmitted using the dedicated dedicated feedback resource. If the time difference is less than the threshold value, the dedicated dedicated feedback resource is ignored and feedback is not performed. In this case, the beam measurement subject 3010 may perform beam feedback in accordance with the procedure below 3045. [

The operations 3045 to 3080 refer to the description of operations 2945 to 2980 described in FIG.

&Lt; Direction information transmitted from the base station for beam change >

A beam change instruction frame transmitted by a base station to change a base station beam (or a terminal beam) used for communication with a terminal includes a base station such as a base station beam ID, a terminal beam ID, a beam pair ID, ID information.

31A and 31B are diagrams showing a frame structure for beam change according to an embodiment of the present invention.

Referring to FIG. 31A, the following frame (or MAC-CE, PHY DCI, or MAC payload) including a 9-bit beam ID may be used. For example, the MAC CE may be a beam change indication MAC CE. The PHY DCI may be indicated from the xPDCCH order.

- BI (9-bit): Field indicating the beam index.

- R: reserved bit, set to "0"

Referring to FIG. 31B, the BS designates a specific beam among the serving beams of the UE and transmits the following frame (or a MAC-CE or a PHY DCI, or a MAC-CE) including a 9-bit beam ID, MAC payload) structure. For example, the MAC CE may be a beam change indication MAC CE. The PHY DCI may be indicated from the xPDCCH order.

- BI_old (9-bit): A field indicating the beam index that the terminal needs to know to change.

- BI_new (9-bit): Field indicating the beam index to be used instead of BI_old.

- R: reserved bit, set to "0"

32A and 32B are views showing a frame structure for beam changing according to another embodiment of the present invention.

Referring to FIG. 32A, the following frame (or MAC-CE, PHY DCI, or MAC payload) including a 3-bit beam ID may be used.

- RBI (3-bit): this field indicates the beam index;

- R: reserved bit, set to "0"

Referring to FIG. 32-2, the following frame (or MAC-CE, PHY DCI, or MAC payload) including a 3-bit beam ID may be used.

- RBI_old (3-bit): A field indicating the beam index that the UE needs to know to change.

- RBI_new (3-bit): field indicating the beam index to be used instead of RBI_old.

- R: reserved bit, set to "0"

The operation of the base station will be described in detail below. The following base station operation can be applied to the specific operation of the base station described in the above embodiments.

&Lt; Method of changing beam >

The operation of the base station for supporting the terminal operating in this way and changing the beam and the beam changing method in use are as follows.

1. A method in which a base station transmits a specific signal and instructs a beam change to be used for communication with a terminal in the future

The base station can change the beam to be used for communication with a specific terminal through the following operation and provide the corresponding information to the terminal.

33 is a diagram illustrating a beam changing method of a base station according to an embodiment of the present invention.

In 3305 operation, the base station may transmit a beam measurement signal. The beam measurement signal may be periodically transmitted. In operation 3310, the base station may allocate a beam feedback resource to the connected terminal. The beam feedback resource may be a periodic dedicated feedback resource.

In operation 3315, the base station may allocate a base station beam change reception period and notify each terminal thereof.

In 3320 operation, the base station receives beam feedback from the terminal. The beam feedback may be received through a dedicated resource allocated by the base station or may be received in a receive beam modification period. The base station can receive feedback from each terminal through a periodic dedicated feedback resource or a reception beam change reception period, and can receive feedback through any resource / interval.

In operation 3325, the base station determines whether to change the beam to be used for the terminal. If it is determined that there is no need to change, operation 3340 can be performed. If there is no request to change the existing terminal use beam to the feedback or it is determined that there is no need to change the beam as a result of analyzing the feedback information, the existing beam can be continuously used.

If it is determined that a beam change is necessary in operation 3325, the operation can proceed to 3330 operation. If it is determined that there is a beam change request in the corresponding beam feedback or that it is necessary to change the beam as a result of analyzing the feedback information, it is determined to change the used beam to the corresponding beam. The base station transmits a beam change request message to the mobile station. In the 3335 operation, the base station changes the used beam at a predetermined or predetermined time.

The beam change signal may be transmitted within a predetermined time (e.g., Timer_feedback_change) after the base station receives specific information (e.g., uplink beam feedback information).

At this time, the BS may inform the UE of information to be transmitted within a predetermined time after receiving the specific information through an RRC message (RRC IE), a MAC message (MAC-CE), and a PHY message (PHY DCI) May be a value that the terminal or base station knows from the implementation, as specified in the standard.

Also, the beam change signal may be implemented or standardized so that the base station can transmit at any time at a desired time.

1. 1. How the base station judges beam changes

The beam change determination method is as follows.

A. If the channel quality or performance of the serving beam (scheduling beam) is below a certain threshold

a1. Current beam measurement <Threshold.

a2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

B. When the channel quality or performance of any other beam other than the currently used beam (serving beam, scheduling beam) is greater than or equal to a certain threshold

b1. New beam measure> Threshold.

b2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, etc.,

C. If the channel quality or performance of another beam is better than a certain threshold / offset compared with the beam currently in use

c1. New Beam Measure> Current Beam Measure + Threshold.

c2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

D. The channel quality or performance of the currently used beam (serving beam, scheduling beam) is below a certain threshold and the channel quality or performance of any other beam other than the currently used beam (serving beam, scheduling beam) Or more

d1. (Current beam measurement value <Threshold_out) & (new beam measurement value> Threshold in)

d2. The measured values may be RSRP, RSRQ, SNR, SINR, CQI, BER, FER, PER, BLER, or the like.

E. Threshold value may be a constant having a fixed value according to the standard, or may be configured by a base station using an RRC message, a MAC-CE, a PHY DCI, or the like. It is possible.

E. When a timer (e.g., Feedback Timer) has expired

e1. When the uplink beam feedback is not received during the timer time, or

e2. When the uplink resource allocation is not transmitted / failed during the corresponding timer time, or

e3. When the mobile station does not receive a successful uplink transmission during the corresponding timer time

F. The upper K (or K%) of the total beam (base station beam, terminal beam, or beam pair) rank reported by the terminal, which is derived from the beam measurement and is currently in use (base station beam, terminal beam, or beam pair) ) &Lt; / RTI &gt;

G. The lower K (or K%) of the currently used beam (base station beam, terminal beam, or beam pair) derived from the beam measurement is the total beam (base station beam, terminal beam, or beam pair) ) &Lt; / RTI &gt;

H. After transmitting any information (MAC PDU, MAC-CE, Data, PHY packet, etc.) requesting a response to the UE, a response (HARQ ACK, RLC ACK, Feedback ACK, , Etc.) is not received

h1. The response request information may be a bit existing at a predetermined position in a predetermined PHY or MAC message. gt;

h2. The response request information may be a predetermined sequence.

h3. The response may be received within a predetermined time after the base station information is transmitted.

1. 2. How the base station changes the beam

The base station / terminal can use a new beam included in the beam change request signal from the corresponding beam change time, and the beam change time and beam changing method are as follows.

The beam change time may have the following values in absolute time: Subframe number, slot number, GPS time, radio frame number, and so on.

The beam change time may have the following values as a relative time: After a specific time (subframe number, slot number, GPS time, radio frame number, etc.) flows from the beam change request signal transmission / reception time, Or after a certain time has elapsed since the (last) ARQ ACK transmission / reception time of the beam change request signal, or after a certain time from the (last) HARQ ACK transmission / reception time of the beam change request signal.

The beam change time is

The beam change time may be specified / transmitted in the beam change request signal,

The base station may configure each terminal with different signals (eg, RRC IE, MAC-CE, PHY DCI, etc.)

The standard may specify a specific offset,

The base station is a Broadcasting Info. (MIB, SIB, etc.).

&Lt; Beam information feedback and beam changing method using RACH procedure >

Various embodiments applying the RACH procedure of LTE, which can be considered to use the beam information feedback and beam changing method, will be described.

We apply the existing RACH procedure and consider the proposed RACH procedure with the following message number.

Message 1 (MSG1): Random access preamble transmission of the UE through the RACH channel

Message 2 (MSG2): Transmits the base station's random access response over the PDCCH channel

Message 3 (MSG3): Buffer Status Report (BSR) of terminal through PUSCH channel or transmission of uplink information or beam feedback information

Message 4 (MSG4): Transmission of Contention Resolution of Base Station over PDCCH Channel

The embodiment discussed in the present invention can be applied to a case where a terminal performs an initial cell connection, performs a cell connection after an RLF occurs, performs a connection in a target cell upon handover, performs beam recovery in determining a beam misalignment , Or performing RACH procedures such as performing paging reception in the idle mode or cell connection due to uplink data generation.

Herein, an operation of performing an RACH procedure when the UE performs initial cell connection will be described.

When a terminal selects a beam (a beam having the best signal quality or a beam having a signal quality higher than a certain threshold value) capable of acquiring downlink synchronization with the base station and communicating with the base station, the terminal transmits the RACH preamble using resources corresponding to the beam . If possible, the UE may perform the uplink transmission including the beam information using the resources following the RACH preamble or immediately after the RACH preamble. The MS receives a response message (i.e., a RAR message) for the RACH preamble from the BS to check whether the RAR message includes the beam feedback indication information. If the RAR message includes the beam feedback indication information, the terminal transmits the feedback on the beam of the base station according to the beam feedback indication information. Wherein the beam feedback indication information includes at least one of a number of beams to feed back the signal strength, a resource to transmit the beam feedback, a time to transmit the beam feedback, a beam feedback format (upper layer message including an L1 signal including a UCI or a MAC CE) At least one of the change point information to be reported to the beam to be reported in the beam feedback is changed in accordance with the format of the indicator for instructing the change to the reporting beam (after the terminal has been notified of the change in the reported beam or received the beam change indicator signal from the base station) Information. According to another embodiment, the resource allocation information to transmit the beam feedback transmission may be received multiplexed with MSG4 or received after MSG4.

Meanwhile, in order to support the beam feedback of the MS in the MSG3, each base station may always allocate resources sufficient to transmit beam feedback to the MS that has received the RA Preamble, and transmit the scheduling information to the RAR . If standardization defines a contention-based RACH that transmits beam feedback in MSG3, all base stations always allocate resources enough to transmit beam feedback to the UE performing the contention-based RACH, Information should be sent.

Meanwhile, the MSG4 may be transmitted including a Beam Change Indication message for beam change.

Meanwhile, the terminal transmitting and receiving the beam feedback according to the beam feedback indication information through the RAR message changes the beam according to the beam feedback information of the terminal or maintains the current beam and performs the following procedure.

After receiving the RAR message, the MS transmits a beam feedback message / signal together with the MSG 3 according to the beam feedback command. Alternatively, the UE transmits a beam feedback message / signal after the MSG3 transmission according to the beam feedback indication information after receiving the RAR message. Alternatively, the UE transmits a beam feedback message / signal before the MSG3 transmission according to the beam feedback indication information after receiving the RAR message. The transmission after the MSG3 corresponds to the transmission time of the MSG3 and the reception time of the MSG4 using a resource different from the MSG3. The transmission after the MSG3 corresponds to a point in time after MSG3 transmission and MSG4 reception using a resource different from MSG3. The MSG3 transmission after the MSG3 corresponds to the MSG3 transmission / MSG4 reception prior to the MSG3 transmission using a separate resource from the MSG3.

If the terminal is to change the beam according to the beam feedback indication information, the terminal changes the beam from the beam change point to the reported beam, and then performs a subsequent communication procedure with the base station.

The terminal receives the beam change indicator signal from the base station and changes the beam to the beam indicated by the beam change indicator signal, and then transmits the beam change indicator signal to the base station, And performs subsequent communication procedures with the base station. Wherein the beam change time point information is determined by a system value or received from the base station.

The beam change indicator signal is an L1 / higher layer signal transmitted in the MSG4 or transmitted together with the MSG4, or a signal transmitted separately from the MSG4. When the beam change indicator signal corresponds to a signal transmitted separately from the MSG 4, the beam change indicator signal transmission time corresponds to the time between the MSG 3 transmission time and the MSG 4 reception time. Or when the beam change indicator signal corresponds to a signal transmitted separately from the MSG4, the beam change indicator signal transmission time corresponds to before the MSG3 transmission time. Or when the beam change indicator signal corresponds to a signal transmitted separately from the MSG4, the beam change indicator signal transmission time corresponds to a time point after the MSG4 reception time.

If the RAR message does not include the beam feedback indication information, the UE can transmit beam feedback through the MSG3 that is transmitted in response to the RAR message. When beam feedback is transmitted in the MSG3, the BS can transmit a beam change indicator through MSG4 or another signaling.

The following is a drawing showing various embodiments described above. 34 is a diagram showing a beam feedback method according to an embodiment of the present invention.

Referring to FIG. 34, the beam feedback is within MSG 3 or multiplexed with MSG 3. Also, the beam change indicator is in the MSG4 or when multiplexed with the MSG4.

Referring to FIG. 34, the UE transmits a random access preamble. The UE may transmit a random access preamble using a beam to be changed. Based on the random access preamble, the base station transmits a random access response. The random access response may include information indicating a beam feedback report. The MS receiving the random access response can transmit MSG3. At this time, it is possible to transmit the signal including the beam feedback in the MSG3, multiplex the MSG3 and the beam feedback together, and transmit the multiplexed signal to the base station. The base station receiving the MSG3 may transmit the MSG4. In the MSG4, beam change indication information may be included, and the MSG4 and the beam change indication information may be multiplexed and transmitted. The beam may change after MSG4 transmission. The beam change may be performed after a certain time has elapsed since the MSG4 transmission.

35 is a diagram showing a beam feedback method according to another embodiment of the present invention.

The procedure for transmitting the random access preamble to the MSG 3 is described with reference to the description of the embodiment of FIG. After MSG3 reception, the base station transmits MSG4. The difference from the embodiment in Fig. 34 is that in the embodiment of Fig. 35, the beam change instruction is transmitted after the MSG4 is transmitted. The base station may transmit a beam change indication after transmitting the MSG4. After transmitting the beam change instruction, the beam may be changed.

36 is a diagram showing a beam feedback method according to another embodiment of the present invention.

The embodiment of Fig. 36 is similar to the embodiment of Fig. 35, and differs in the point of time at which the beam change instruction is transmitted. After receiving the MSG3, the BS transmits a beam change instruction to the MS before transmitting the MSG4. After the beam change instruction, the beam is changed. The base station may transmit the MSG4 using the modified beam.

37 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of Fig. 37 is similar to the embodiment of Fig. 36, and the beam change points are different. In the embodiment of FIG. 37, the beam is changed by the base station after the beam change instruction and the MSG4 transmission.

38 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of FIG. 38 is similar to the embodiment of FIG. 36 or 37, but does not explicitly transmit a beam change instruction. There is no separate beam change signaling (implicit beam change indication), but the beam may change after MSG3 reception of the base station or after MSG4 transmission of the base station.

39 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of Fig. 39 differs from the embodiment of Figs. 36 and 37 in the point of time at which the beam change command is transmitted and the beam change point. In addition, beam feedback is not included or multiplexed in MSG 3, and the beam is fed back in a separate procedure. The MS receiving the random access response transmits the beam feedback information before the MSG3 transmission. The base station that has received the beam feedback instructs the beam change. The beam is then changed. After the beam change, the terminal transmits MSG3 and the base station transmits MSG4. MSG3 and MSG4 can be transmitted via the modified beam.

40 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of FIG. 40 differs from the embodiment of FIG. 39 in the point of time when MSG3 is transmitted. After beam feedback transmission, the terminal transmits MSG 3. After the MSG3 transmission, the base station transmits a beam change indication and the beam changes after the beam change transmission. The MSG4 may be transmitted via the modified beam.

41 is a diagram showing a beam feedback method according to another embodiment of the present invention. 41 is an embodiment in which a separate beam change indicator is not transmitted as compared with the embodiment of FIG. The base station does not transmit a separate beam change indication after receiving the beam feedback. However, after a certain time has elapsed since beam feedback, the beam changes.

42 is a diagram showing a beam feedback method according to another embodiment of the present invention. 42 differs from the embodiment of FIG. 39 in the beam-feedback transmission time point and the beam-change direction transmission time point. After MSG1 to MSG4 transmission / reception, the UE transmits beam feedback. The base station then transmits a beam change indication and the beam changes after the beam change indication transmission.

43 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of FIG. 43 omits the procedure for transmitting a separate beam change instruction when compared with the embodiment of FIG. The beam change indication may be performed implicitly. The beam feedback transmission resource information may be indicated in the RAR transmission or indicated in the MSG4 transmission or separately after the MSG4 transmission.

44 is a diagram showing a beam feedback method according to another embodiment of the present invention. The embodiment of FIG. 44 is a case where the beam report instruction is not included in the RAR, as compared with the embodiment of FIG. If the RAR message does not include the beam feedback instruction information, the beam-feedback and beam-change instruction can be transmitted and received through the MSG3 and the MSG4, respectively. After the MSG4 includes the explicit beam change indication information or the MSG4 and Explicit beam The change indication signal can be multiplexed.

In the case of the RACH procedure performed during handover to the target cell, the BS and the MS, which have transmitted and received the RAR message including the beam report indication information without transmitting / receiving the MSG3 or MSG4, The beam change signal can be transmitted and received. Also in this case, the beam report indication information includes at least one of the resource allocation information for the beam feedback signal, the transmission of the implicit / explicit beam change signal, and the resource allocation information for the beam change signal.

45 is a diagram showing a beam feedback method according to another embodiment of the present invention. When handover is performed, beam-feedback transmission may be performed after RAR transmission / reception including beam report indication information. Implicit beam change indicator based beam change can be performed.

46 is a diagram showing a beam feedback method according to another embodiment of the present invention. The base station can temporarily allocate resources using the RACH preamble received beam through the RAR. In this case, if a single RACH preamble is received, the base station allocates one RACH to the RACH preamble. If the RACH preamble is received by the same terminal, the RAS can be transmitted using the most preamble among the received preambles have. Beam feedback may be multiplexed with MSG3 or with MSG3 and the beam change indication may be multiplexed with MSG4 or MSG4.

47 is a view showing a beam feedback method according to another embodiment of the present invention. The base station can instruct the beam change to use the best beam received from the RACH preamble through the RAR as a serving beam. In this case, if a single RACH preamble is received, the base station allocates one RACH to the RACH preamble. If the RACH preamble is received by the same terminal, the RAS can be transmitted using the most preamble among the received preambles have. The base station and the terminal can perform the transmission operation of Msg 3 and Msg 4 after changing to the corresponding beam.

48 is a diagram showing a beam feedback method according to another embodiment of the present invention. The beam may be changed after the RAR transmission / reception including the beam change instruction information. Explicit beam change indicator based beam change is performed, and the corresponding beam change indication may be separately transmitted separately from the RAR transmission.

The beam change indication message may be included in the form of a MAC-CE or may be multiplexed in a form of one field in the DCI.

In the case of the RACH procedure performed when handing over to the target cell, the BS and the UE, which have transmitted and received the RAR message and the beam change indication message without transmitting / receiving the MSG3 or MSG4, can change the serving beam to the corresponding beam. Also in this case, the beam report indication information includes at least one of the resource allocation information for the beam feedback signal, the transmission of the implicit / explicit beam change signal, and the resource allocation information for the beam change signal.

49 is a diagram showing a beam feedback method according to another embodiment of the present invention. The beam may be changed after the RAR transmission / reception including the beam change instruction information. Explicit beam change indicator based beam change is performed, and the corresponding beam change indication may be separately transmitted separately from the RAR transmission.

In the above embodiments, the RACH preamble is a message for transmitting the SR request signal (or the SR request preamble) of the UE, the RAR transmission using the UL Grant transmission of the base station, and the Msg 3 using the resource allocated to the UL grant for the SR transmission And Msg 4 may be replaced with a response message of the base station for the message transmitted by the UE through the UL grant allocation resource of the base station for SR transmission.

Also, in the above embodiments, the RACH-related transmission may be a part of the Dedicated RACH.

50 is a diagram illustrating a terminal according to an embodiment of the present invention.

Referring to FIG. 50, the terminal 5000 may include a transmission / reception unit 5010 and a control unit 5030 for transmitting and receiving signals. The terminal 5000 can transmit and / or receive signals, information, messages, and the like through the transmission / reception unit 5010. The control unit 5030 can control the overall operation of the terminal 5000. The control unit 5030 may include at least one processor. The control unit 5030 can control the operation of the terminal described with reference to FIG. 1 through FIG.

The controller 5030 receives the beam feedback trigger condition and determines whether the beam feedback trigger condition is satisfied. If it is determined that the beam feedback trigger condition is satisfied, Based on the beam feedback trigger, to transmit a control element (MAC CE) including beam feedback information. The beam feedback trigger condition may include a case where the channel measurement value of at least one beam is greater than a sum of a predetermined threshold value and a channel measurement value of the current serving beam.

In addition, if the uplink of the UE is synchronized, the controller 5030 can control to transmit the beam feedback information using the UL allocation resources received through a scheduling re-order (SR) procedure. The terminal may transmit the SR and receive information on resources allocated for beam feedback based on the SR transmission. Resource allocation may be performed periodically or non-periodically.

In addition, if the uplink of the UE is not synchronized, the controller 5030 may control to transmit the beam feedback information through a random access procedure. When the beam feedback is triggered, transmitting a random access preamble, receiving a random access response in response to a random access preamble transmission, transmitting the beam feedback information based on receiving a random access response, It is possible to control to receive the random access contention result. The message transmitting the beam feedback information may be MSG3 in the random access procedure.

In addition, the controller 5030 receives the beam change instruction information, and upon receiving the beam change instruction information, controls the beam controller 5030 to change the beam based on the beam feedback information after a predetermined time.

51 is a diagram illustrating a base station according to an embodiment of the present invention.

Referring to FIG. 51, the base station 5100 may include a transmission / reception unit 5110 and a control unit 5130 for transmitting and receiving signals. The base station 5100 can transmit and / or receive signals, information, messages, and the like through the transmission / reception unit 5110. The control unit 5130 can control the overall operation of the base station 5100. The control unit 5130 may include at least one processor. The controller 5130 can control the operation of the base station described with reference to FIG. 1 through FIG. 49.

In addition, the controller 5130 may transmit a beam-feedback triggering condition to the terminal and control the terminal to receive a medium access control (CE) control element (CE) including beam-feedback information. The beam-feedback information may be triggered when it is determined that the beam-feedback condition is satisfied in the MAC layer of the UE. That is, the beam feedback condition can be triggered according to the determination of the MAC layer of the UE. The beam feedback trigger condition may include a case where the channel measurement value of at least one beam is greater than a sum of a predetermined threshold value and a channel measurement value of the current serving beam.

In addition, if the uplink of the UE is synchronized, the controller 5130 allocates uplink resources to the UE through a scheduling re-order (SR) procedure, and outputs the beam feedback information from the allocated uplink resources Can be controlled.

In addition, if the uplink of the UE is not synchronized, the controller 5130 can control to receive the beam feedback information through a random access procedure. Receiving a random access preamble from the terminal, transmitting a random access response based on a random access preamble reception, receiving the beam feedback information in response to a random access response transmission, And control the transmission of the results. The message receiving the beam feedback information may be MSG3 in the random access procedure.

In addition, the controller 5130 transmits the beam change instruction information based on the reception of the beam feedback information. When the beam change instruction information is transmitted, the controller 5130 controls to change the beam based on the beam feedback information after a predetermined time have.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. Accordingly, the scope of the present invention should be construed as being included in the scope of the present invention, all changes or modifications derived from the technical idea of the present invention.

Claims (22)

In a beam feedback method of a terminal,
Receiving a beam feedback trigger condition;
Determining whether the beam feedback trigger condition is satisfied;
Triggering beam feedback at a medium access control (MAC) layer of the terminal if the beam feedback trigger condition is satisfied; And
Based on the beam feedback trigger, transmitting a MAC CE (control element) including beam feedback information. The method of claim 1, wherein if the uplink of the UE is synchronized, the beam feedback information is transmitted using the UL allocated resource through a scheduling re-order (SR) procedure. The method of claim 1, wherein if the uplink of the UE is not synchronized, transmitting the beam feedback information through a random access procedure. 4. The method of claim 3,
When the beam feedback is triggered, transmitting a random access preamble,
Receiving a random access response in response to the random access preamble transmission,
Transmitting the beam feedback information based on the random access response reception, and
And receiving a random access contention result corresponding to the beam feedback information transmission. 2. The method of claim 1, wherein the beam feedback trigger condition comprises a case where a channel measurement of at least one beam is greater than a sum of a predetermined threshold and a channel measurement of the current serving beam. The method of claim 1, further comprising: receiving beam change indication information; And
And upon receiving the beam change indication information, changing the beam based on the beam feedback information after a predetermined time. In the terminal,
A transmitting and receiving unit for transmitting and receiving signals; And
The method comprising: receiving a beam feedback trigger condition; determining whether the beam feedback trigger condition is satisfied; and determining that the beam feedback trigger condition is satisfied, triggering beam feedback in a medium access control (MAC) layer of the terminal, Based on a feedback trigger, control to transmit a MAC CE (control element) including beam feedback information. 8. The apparatus of claim 7,
Wherein if the uplink of the UE is synchronized, control is performed to transmit the beam feedback information using uplink allocated resources through a scheduling re-order (SR) procedure. 8. The apparatus of claim 7,
And to transmit the beam-feedback information through a random access procedure if the uplink of the UE is not synchronized. 10. The apparatus according to claim 9,
When the beam feedback is triggered, transmitting a random access preamble, receiving a random access response in response to a random access preamble transmission, transmitting the beam feedback information based on receiving a random access response, A terminal that controls to receive a random access contention result. 8. The terminal of claim 7, wherein the beam feedback trigger condition comprises a case where a channel measurement of at least one beam is greater than a sum of a predetermined threshold and a channel measurement of the current serving beam. 8. The apparatus of claim 7,
And receives the beam change indication information, and upon receiving the beam change indication information, changes the beam based on the beam feedback information after a predetermined time. In the beam-feedback reception of the base station,
Transmitting a beam feedback trigger condition to a terminal; And
And receiving a medium access control (CE) control element (CE) including beam feedback information from the terminal,
Wherein the beam feedback information is triggered when it is determined in the MAC layer of the terminal that the beam feedback condition is satisfied. 14. The method of claim 13, further comprising: allocating uplink resources to the UE through a scheduling re-order (SR) procedure if the uplink of the UE is synchronized,
And receiving the beam feedback information from the allocated uplink resource. 14. The method of claim 13, wherein if the uplink of the UE is not synchronized,
Receiving a random access preamble from the terminal,
Transmitting a random access response based on the random access preamble reception,
Receiving the beam feedback information in response to the random access response transmission, and
And transmitting a random access contention result based on receiving the beam feedback information. 14. The method of claim 13, wherein the beam feedback trigger condition comprises a case where the channel measurement of at least one beam is greater than a sum of a predetermined threshold and a channel measurement of the current serving beam. 14. The method of claim 13, further comprising: transmitting beam change indication information based on reception of the beam feedback information; And
Modifying the beam based on the beam feedback information after a predetermined time when transmitting the beam change indication information. In the base station,
A transmitting and receiving unit for transmitting and receiving signals; And
And a controller for transmitting a beam feedback trigger condition to the terminal and receiving a medium access control (CE) control element (CE) including beam feedback information from the terminal,
Wherein the beam-feedback information is triggered when it is determined that the beam-feedback condition is satisfied in the MAC layer of the UE. 19. The apparatus of claim 18,
Wherein when the uplink of the UE is synchronized, the uplink resource is allocated to the UE through a scheduling re-order (SR) procedure, and the beam feedback information is received from the allocated uplink resource. 19. The apparatus of claim 18, wherein the controller is configured to, if the uplink of the terminal is not synchronized,
Receiving a random access preamble from the terminal, transmitting a random access response based on a random access preamble reception, receiving the beam feedback information in response to a random access response transmission, And controls to transmit the result. 19. The base station of claim 18, wherein the beam feedback trigger condition comprises a case where the channel measurement of at least one beam is greater than a sum of a predetermined threshold and a channel measurement of the current serving beam. 19. The apparatus of claim 18,
And transmits the beam change indication information based on the received beam feedback information and controls to change the beam based on the beam feedback information after a predetermined time when the beam change indication information is transmitted.

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