WO2019054755A1

WO2019054755A1 - Method and device for wireless signal transmission or reception in wireless communication system

Info

Publication number: WO2019054755A1
Application number: PCT/KR2018/010701
Authority: WO
Inventors: 박창환; 김선욱; 박한준; 안준기; 양석철
Original assignee: 엘지전자 주식회사
Priority date: 2017-09-12
Filing date: 2018-09-12
Publication date: 2019-03-21

Abstract

The present invention relates to a wireless communication system and, specifically, provides a method and a device therefor, the method comprising the steps of: receiving a downlink signal on a carrier; performing a detection procedure for an SS-block with respect to the downlink signal, wherein the SS-block includes a plurality of contiguous OFDM symbols on the basis of a predetermined SCS; and acquiring downlink synchronization through the detection procedure, wherein the predetermined SCS belongs to a first SCS set or a second SCS set on the basis of a type of the carrier, and the first SCS set and the second SCS set are not the same.

Description

Method and apparatus for transmitting and receiving wireless signals in a wireless communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a wireless signal transmission and reception method and apparatus.

Background of the Invention [0002] Wireless communication systems are widely deployed to provide various types of communication services such as voice and data. Generally, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access) systems.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for efficiently performing a wireless signal transmission and reception process.

The technical problems to be solved by the present invention are not limited to the technical problems and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a method for a terminal to acquire downlink synchronization in a wireless communication system, the method comprising: receiving a downlink signal on a carrier; Performing a detection of a synchronization signal (SS) block on the downlink signal, the SS-block including a plurality of consecutive Orthogonal Frequency Division Multiplexing (OFDM) symbols based on a predetermined subcarrier spacing (SCS); And acquiring the downlink synchronization through the detection process, wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of the carrier, 2 SCS sets are provided in the same way.

According to another aspect of the present invention, there is provided a terminal used in a wireless communication system, the terminal comprising: a Radio Frequency (RF) module; And a processor for receiving a downlink signal on a carrier and performing a detection of a synchronization signal (SS) block on the downlink signal, wherein the SS-block includes a subcarrier spacing (SCS) Wherein the predetermined SCS is configured to obtain a first SCS set based on a type of the carrier, wherein the predetermined SCS is a first SCS set based on a type of the carrier, Or a second SCS set, wherein the first SCS set and the second SCS set are not the same.

Preferably, the first set of SCSs is used when the carrier is a license band, the second set of SCSs is used when the carrier is a license-exempt band, and the first set of SCSs comprises 15 kHz, 30 kHz, 120 kHz and 240 kHz And the second set of SCSs may comprise 60 kHz.

Preferably, the first SCS set may not include 60 kHz.

Preferably, when a plurality of SS-blocks are included in a 1 ms time unit and the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit, If the carrier is a license-exempt band, the plurality of SS-blocks may be consecutively bounded by the 0.5 ms time point within the 1 ms time unit.

Preferably, the 1 ms time unit comprises 14 OFDM symbols on a 15 kHz SCS basis, and each SS-block may comprise 4 consecutive OFDM symbols.

According to another aspect of the present invention, there is provided a method of providing downlink synchronization in a wireless communication system, the method comprising the steps of: generating a synchronization signal (SS) block, the SS block including a plurality of consecutive (Orthogonal Frequency Division Multiplexing) symbol; And transmitting the downlink signal including the SS-block on a carrier, wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of the carrier, The second SCS set is provided in a manner that is not the same.

According to another aspect of the present invention, there is provided a base station used in a wireless communication system, the base station comprising: a Radio Frequency (RF) module; And a processor, wherein the processor generates a synchronization signal (SS) block, wherein the SS-block includes a plurality of contiguous Orthogonal Frequency Division Multiplexing (OFDM) symbols based on a predetermined subcarrier spacing (SCS) Block, the predetermined SCS belonging to a first SCS set or a second SCS set, based on the type of the carrier, wherein the first SCS set and the second SCS set are configured to transmit a downlink signal including the SS- The SCS set is provided with an unequal base station.

Preferably, the first SCS set may not include 60 kHz.

According to the present invention, wireless signal transmission and reception can be efficiently performed in a wireless communication system.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 illustrates physical channels used in a 3GPP LTE (-A) system, which is an example of a wireless communication system, and a general signal transmission method using them.

Fig. 2 illustrates the structure of a radio frame.

3 illustrates a resource grid of a downlink slot.

4 shows a structure of a downlink sub-frame.

5 illustrates a structure of an uplink subframe used in LTE (-A).

Figure 6 illustrates the structure of a self-contained subframe.

Figure 7 illustrates the frame structure defined in 3GPP NR.

Figure 8 illustrates the merging of licensed bands and unlicensed bands.

Figure 9 illustrates a method of occupying resources within a license-exempt band.

10 to 13 illustrate a synchronization signal block (SSB) configuration.

Figures 14-37 illustrate SSB configuration / detection in accordance with the present invention.

38 illustrates a base station and a terminal that can be applied to the present invention.

The following description is to be understood as illustrative and non-limiting, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access And can be used in various wireless access systems. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long term evolution (LTE) is part of E-UMTS (Evolved UMTS) using E-UTRA and LTE-A (Advanced) is an evolved version of 3GPP LTE. For clarity of description, 3GPP LTE / LTE-A is mainly described, but the technical idea of the present invention is not limited thereto.

In a wireless communication system, a terminal receives information from a base station through a downlink (DL), and the terminal transmits information through an uplink (UL) to a base station. The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / use of the information transmitted / received.

1 is a view for explaining a physical channel used in a 3GPP LTE (-A) system and a general signal transmission method using the same.

The terminal that is powered on again or the cell that has entered a new cell performs an initial cell search operation such as synchronizing with the base station in step S101. To this end, a mobile station receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from a base station and synchronizes with the base station and stores information such as a cell identity . Then, the terminal can receive the physical broadcast channel (PBCH) from the base station and obtain the in-cell broadcast information. Meanwhile, the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE receives a Physical Downlink Control Channel (PDCCH) and a physical downlink control channel (PDSCH) according to physical downlink control channel information in step S102, System information can be obtained.

Then, the terminal may perform a random access procedure such as steps S103 to S106 to complete the connection to the base station. To this end, the UE transmits a preamble through a Physical Random Access Channel (PRACH) (S103), and transmits a response message for a preamble through the physical downlink control channel and the corresponding physical downlink shared channel (S104). In the case of contention based random access, the transmission of the additional physical random access channel (S105) and the physical downlink control channel and corresponding physical downlink shared channel reception (S106) ). &Lt; / RTI >

The UE having performed the procedure described above transmits a physical downlink control channel / physical downlink shared channel reception step S107 and a physical uplink shared channel (PUSCH) / physical downlink shared channel A Physical Uplink Control Channel (PUCCH) transmission (S108) may be performed. The control information transmitted from the UE to the Node B is collectively referred to as Uplink Control Information (UCI). The UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and Request Acknowledgment / Negative ACK), SR (Scheduling Request), CSI (Channel State Information) The CSI includes a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indication (RI), and the like. The UCI is generally transmitted through the PUCCH, but may be transmitted via the PUSCH when the control information and the traffic data are to be simultaneously transmitted. In addition, UCI can be transmitted non-periodically through the PUSCH according to the request / instruction of the network.

Fig. 2 illustrates the structure of a radio frame. The uplink / downlink data packet transmission is performed in units of subframes, and a subframe is defined as a time interval including a plurality of symbols. The 3GPP LTE standard supports a Type 1 radio frame structure applicable to Frequency Division Duplex (FDD) and a Type 2 radio frame structure applicable to TDD (Time Division Duplex).

2 (a) illustrates the structure of a Type 1 radio frame. The downlink radio frame is composed of 10 subframes, and one subframe is composed of two slots in a time domain. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, the length of one subframe may be 1 ms and the length of one slot may be 0.5 ms. One slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. In the 3GPP LTE system, since OFDM is used in the downlink, an OFDM symbol represents one symbol period. An OFDM symbol may also be referred to as an SC-FDMA symbol or a symbol interval. A resource block (RB) as a resource allocation unit may include a plurality of consecutive subcarriers in one slot.

The number of OFDM symbols included in the slot may vary according to the configuration of the CP (Cyclic Prefix). CP has an extended CP and a normal CP. For example, when an OFDM symbol is configured by a normal CP, the number of OFDM symbols included in one slot may be seven. When the OFDM symbol is configured by the extended CP, since the length of one OFDM symbol is increased, the number of OFDM symbols included in one slot is smaller than that of the normal CP. For example, in the case of the extended CP, the number of OFDM symbols included in one slot may be six. If the channel state is unstable, such as when the UE moves at a high speed, an extended CP may be used to further reduce inter-symbol interference.

When a normal CP is used, the slot includes 7 OFDM symbols, so that the subframe includes 14 OFDM symbols. The first three OFDM symbols at the beginning of a subframe may be allocated to a physical downlink control channel (PDCCH), and the remaining OFDM symbols may be allocated to a physical downlink shared channel (PDSCH).

2 (b) illustrates the structure of a Type 2 radio frame. The Type 2 radio frame is composed of two half frames. The half frame includes 4 (5) normal sub-frames and 1 (0) special sub-frames. The normal subframe is used for uplink or downlink according to the UL-DL configuration (Uplink-Downlink Configuration). The subframe consists of two slots.

Table 1 illustrates a subframe configuration in a radio frame according to the UL-DL configuration.

Uplink-downlink configuration

Downlink-to-Uplink Switch point periodicity

Subframe number

0

One

2

3

4

5

6

7

8

9

0

5ms

D

S

U

D

S

U

One

5ms

D

S

U

D

S

U

D

2

5ms

D

S

U

D

S

U

D

3

10ms

D

S

U

D

4

10ms

D

S

U

D

5

10ms

D

S

U

D

6

5ms

D

S

U

D

S

U

D

In the table, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The special subframe includes a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS). The DwPTS is used for initial cell search, synchronization, or channel estimation in the UE. UpPTS is used to synchronize the channel estimation at the base station and the uplink transmission synchronization of the UE. The guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.

The structure of the radio frame is merely an example, and the number of subframes, the number of slots, and the number of symbols in the radio frame can be variously changed.

3 illustrates a resource grid of a downlink slot.

Referring to FIG. 3, the downlink slot includes a plurality of OFDM symbols in the time domain. Here, one downlink slot includes seven OFDM symbols, and one resource block (RB) is illustrated as including 12 subcarriers in the frequency domain. However, the present invention is not limited thereto. Each element on the resource grid is referred to as a Resource Element (RE). One RB includes 12 x 7 REs. The number NDL of RBs included in the downlink slot depends on the downlink transmission band. The structure of the uplink slot may be the same as the structure of the downlink slot.

4 illustrates a structure of a downlink subframe.

Referring to FIG. 4, a maximum of 3 (4) OFDM symbols located in front of a first slot in a subframe corresponds to a control region to which a control channel is allocated. The remaining OFDM symbol corresponds to a data area to which a physical downlink shared chanel (PDSCH) is allocated, and the basic resource unit of the data area is RB. Examples of downlink control channels used in LTE include physical control format indicator channel (PCFICH), physical downlink control channel (PDCCH), physical hybrid ARQ indicator channel (PHICH), and the like. The PCFICH is transmitted in the first OFDM symbol of the subframe and carries information about the number of OFDM symbols used for transmission of the control channel in the subframe. The PHICH is a response to an uplink transmission and carries an HARQ ACK / NACK (acknowledgment / negative-acknowledgment) signal. The control information transmitted via the PDCCH is referred to as DCI (downlink control information). The DCI includes uplink or downlink scheduling information or an uplink transmission power control command for an arbitrary terminal group.

The control information transmitted through the PDCCH is called DCI (Downlink Control Information). The DCI format defines the

formats

0, 3, 3A and 4 for the uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B and 2C for the downlink. Depending on the DCI format, the type of the information field, the number of information fields, and the number of bits of each information field are different. For example, the DCI format may include a hopping flag, an RB assignment, a modulation coding scheme (MCS), a redundancy version (RV), a new data indicator (NDI), a transmit power control (TPC) A HARQ process number, a precoding matrix indicator (PMI) confirmation, and the like. Therefore, the size (size) of the control information matched to the DCI format differs according to the DCI format. On the other hand, an arbitrary DCI format can be used for transmission of two or more types of control information. For example, DCI format 0 / 1A is used to carry either DCI format 0 or DCI format 1, which are separated by a flag field.

The PDCCH includes a transmission format and a resource allocation of a downlink shared channel (DL-SCH), resource allocation information on an uplink shared channel (UL-SCH), paging information on a paging channel (PCH), system information , Resource allocation information of a higher-layer control message such as a random access response transmitted on the PDSCH, transmission power control command for an individual terminal in an arbitrary terminal group, activation of VoIP (voice over IP), and the like . A plurality of PDCCHs may be transmitted within the control domain. The UE can monitor a plurality of PDCCHs. The PDCCH is transmitted on one or a plurality of consecutive control channel element (CCE) aggregations. The CCE is a logical allocation unit used to provide a PDCCH of a predetermined coding rate according to a state of a radio channel. The CCE corresponds to a plurality of resource element groups (REGs). The format of the PDCCH and the number of bits of the available PDCCH are determined according to the correlation between the number of CCEs and the code rate provided by the CCE. The base station determines the PDCCH format according to the DCI to be transmitted to the UE, and adds a CRC (cyclic redundancy check) to the control information. The CRC is masked with a unique identifier (called a radio network temporary identifier (RNTI)) according to the owner of the PDCCH or usage purpose. If the PDCCH is for a particular terminal, the unique identifier of the terminal (e.g., C-RNTI (cell-RNTI)) is masked in the CRC. In another example, if the PDCCH is for a paging message, a paging indication identifier (e.g., P-RNTI (p-RNTI)) is masked to the CRC. If the PDCCH is related to system information (more specifically, a system information block (SIB) described later), a system information identifier (e.g. SI-RNTI) is masked in the CRC. A random access-RNTI (RA-RNTI) is masked in the CRC to indicate a random access response, which is a response to the transmission of the terminal's random access preamble.

The PDCCH carries a message known as Downlink Control Information (DCI), and the DCI includes resource allocation and other control information for one terminal or terminal group. In general, a plurality of PDCCHs may be transmitted in one subframe. Each PDCCH is transmitted using one or more CCEs (Control Channel Elements), and each CCE corresponds to nine sets of four resource elements. The four resource elements are referred to as Resource Element Groups (REGs). Four QPSK symbols are mapped to one REG. The resource element assigned to the reference signal is not included in the REG, and thus the total number of REGs within a given OFDM symbol depends on the presence of a cell-specific reference signal. The REG concept (i.e., group-by-group mapping, each group including four resource elements) is also used for other downlink control channels (PCFICH and PHICH). That is, REG is used as a basic resource unit of the control area. Four PDCCH formats are supported as listed in Table 2.

PDCCH formatPDCCH format	Number of CCEs (n)Number of CCEs (n)	Number of REGsNumber of REGs	Number of PDCCH bitsNumber of PDCCH bits
00	1One	99	7272
1One	22	88	144144
22	44	3636	288288
33	55	7272	576576

CCEs are used consecutively numbered, and in order to simplify the decoding process, a PDCCH with a format composed of n CCEs can only be started with a CCE having the same number as a multiple of n. The number of CCEs used for transmission of a specific PDCCH is determined by the base station according to the channel condition. For example, if the PDCCH is for a terminal with a good downlink channel (e.g., close to the base station), a single CCE may be sufficient. However, for a terminal with a bad channel (e. G., Near cell boundaries), eight CCEs may be used to obtain sufficient robustness. In addition, the power level of the PDCCH can be adjusted to meet the channel conditions.

The approach introduced in LTE is to define a limited set of CCE locations where the PDCCH can be located for each terminal. A limited set of CCE locations where a terminal can locate its PDCCH may be referred to as a Search Space (SS). In LTE, the search space has a different size according to each PDCCH format. In addition, UE-specific and common search spaces are separately defined. The UE-Specific Search Space (USS) is set individually for each UE, and the range of the Common Search Space (CSS) is known to all UEs. The UE-specific and common search space may overlap for a given UE. In case of having a fairly small search space, since there is no remaining CCE when some CCE locations are allocated in a search space for a specific UE, the base station in the given subframe may not be able to find CCE resources to transmit PDCCH to all available UEs. In order to minimize the possibility of such blocking leading to the next sub-frame, a UE-specific hopping sequence is applied to the starting position of the UE-specific search space.

Table 3 shows the sizes of common and UE-specific search spaces.

PDCCH formatPDCCH format	Number of CCEs (n)Number of CCEs (n)	Number of candidates in common search spaceNumber of candidates in common search space	Number of candidates in dedicated search spaceNumber of candidates in dedicated search space
00	1One	--	66
1One	22	--	66
22	44	44	22
33	88	22	22

In order to keep the computational load under the total number of blind decodings (BDs) under control, the terminal is not required to search all defined DCI formats simultaneously. Generally, within a UE-specific search space, the terminal always searches formats 0 and 1A. Formats 0 and 1A have the same size and are separated by flags in the message. In addition, the terminal may be required to receive an additional format (e.g., 1, 1B or 2 depending on the PDSCH transmission mode set by the base station). In the common search space, the terminal searches Formats 1A and 1C. Further, the terminal can be set to search Format 3 or 3A. Formats 3 and 3A have the same size as formats 0 and 1A and can be distinguished by scrambling the CRC with different (common) identifiers, rather than with a terminal-specific identifier. PDSCH transmission scheme according to transmission mode, and information contents of DCI formats are listed below.

Transmission Mode (TM)

● Transmission mode 1: Transmission from single base station antenna port

● Transmission mode 2: Transmit diversity

● Transmission mode 3: Open-loop space multiplexing

● Transmission mode 4: closed-loop spatial multiplexing

● Transmission mode 5: Multi-user MIMO

● Transmission mode 6: closed-loop rank-1 precoding

● Transmission mode 7: Single-antenna port (port 5) transmission

● Transmission Mode 8: Transmission of dual-layer transmission (ports 7 and 8) or single-antenna port (ports 7 or 8)

● Transmission mode 9: Transmission of up to 8 layers (ports 7 to 14) or single-antenna port (ports 7 or 8)

DCI format

● Format 0: Resource Grant for PUSCH transmission (uplink)

● Format 1: Resource allocation for single codeword PDSCH transmission (

transmission modes

1, 2 and 7)

● Format 1A: Compact signaling of resource allocation for single codeword PDSCH (all modes)

Format 1B: Compact resource allocation for PDSCH (mode 6) using rank-1 closed-loop precoding

● Format 1C: Very compact resource allocation for PDSCH (eg, paging / broadcast system information)

● Format 1D: Compact resource allocation for PDSCH (mode 5) using multi-user MIMO

Format 2: Closed - Resource allocation for PDSCH (mode 4) of root MIMO operation

Format 2A: resource allocation for PDSCH (mode 3) of open-loop MIMO operation

● Format 3 / 3A: Power control command with 2-bit / 1-bit power adjustment value for PUCCH and PUSCH

5 illustrates a structure of an uplink subframe used in LTE (-A).

Referring to FIG. 5, the subframe 500 is composed of two 0.5 ms slots 501. Assuming a length of a normal cyclic prefix (CP), each slot is composed of 7 symbols 502, and one symbol corresponds to one SC-FDMA symbol. A resource block (RB) 503 is a resource allocation unit corresponding to 12 subcarriers in the frequency domain and one slot in the time domain. The structure of the uplink sub-frame of the LTE (-A) is roughly divided into a data area 504 and a control area 505. The data region refers to a communication resource used for transmitting data such as voice and packet transmitted to each terminal and includes a physical uplink shared channel (PUSCH). The control region means a communication resource used for transmitting an uplink control signal, for example, a downlink channel quality report from each terminal, a reception ACK / NACK for a downlink signal, an uplink scheduling request, etc., and a PUCCH Control Channel). A sounding reference signal (SRS) is transmitted through a SC-FDMA symbol located last in the time axis in one subframe. The SRSs of the UEs transmitted in the last SC-FDMA of the same subframe can be classified according to the frequency location / sequence. The SRS is used to transmit the uplink channel state to the base station, and is periodically transmitted according to the subframe period / offset set by the upper layer (e.g., RRC layer) or aperiodically transmitted according to the request of the base station.

As more and more communication devices require more communication capacity, there is a need for improved mobile broadband communication over existing RAT (Radio Access Technology). In addition, massive MTC (Machine Type Communications), which provides a variety of services by connecting many devices and objects, is one of the major issues to be considered in next generation communications. In addition, a communication system design considering a service / terminal sensitive to reliability and latency is being discussed. The introduction of the next generation RAT considering eMBB, massive MTC, URLLC (Ultra-Reliable and Low Latency Communication) is discussed. In the present invention, the corresponding technology is referred to as NR (New Radio or New RAT) .

The frame structure of the 3GPP NR is characterized by a self-contained structure in which a DL control channel, DL or UL data, a UL control channel, etc. can be included in one slot unit as shown in FIG. At this time, in the DL control channel, DL data scheduling information, UL data scheduling information, and the like can be transmitted. In the UL control channel, ACK / NACK information, CSI information, SR, and the like for DL data can be transmitted. In FIG. 6, a time gap for DL-to-UL or UL-to-DL switching may exist between the control region and the data region. In addition, some of DL control / DL data / UL data / UL control may not be configured in one slot. Or, the order of each channel constituting one slot may be changed (e.g., DL control / DL data / UL control / UL data or UL control / UL data / DL control / DL data, etc.).

In the 3GPP NR system environment, OFDM parameters such as subcarrier spacing (SCS) and duration of an OFDM symbol (OS) based thereon may be set differently between a plurality of cells merged into one UE. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot or TTI) (for convenience, TU (Time Unit)) composed of the same number of symbols can be set differently between merged cells. Here, the symbol may include an OFDM symbol and an SC-FDMA symbol.

Figure 7 illustrates the frame structure defined in 3GPP NR. Like the radio frame structure of LTE / LTE-A (see FIG. 2), one radio frame in 3GPP NR is composed of 10 subframes, and each subframe has a length of 1 ms. One subframe includes one or more slots and the slot length depends on the SCS. 3GPP NR supports SCS at 15KHz, 30KHz, 60KHz, 120KHz and 240KHz. Here, the slot corresponds to the TTI in Fig.

Table 4 illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe are different according to SCS.

SCS (152^u)SCS (15 2 ^ u)	슬롯 내심볼의 개수Number of symbols in the slot	프레임 내슬롯의 개수Number of slots in the frame	서브프레임 내슬롯의 개수Number of slots in subframe
15KHz (u=0)15KHz (u = 0)	1414	1010	1One
30KHz (u=1)30 kHz (u = 1)	1414	2020	22
60KHz (u=2)60 kHz (u = 2)	1414	4040	44
120KHz (u=3)120KHz (u = 3)	1414	8080	88
240KHz (u=4)240 kHz (u = 4)	1414	160160	1616

Figure 8 illustrates carrier aggregation of license and license-exempt bands. 8, when a base station transmits a signal to a mobile station under a carrier aggregation state of a license band (LTE-A band, L-band) and a license-exempt band (hereinafter, LTE-U band and U-band) A signal can be transmitted to the base station. Here, a cell (e.g., PCell, SCell) operating in the L-band is defined by LCell, and a carrier of the LCell is defined by (DL / UL) LCC. In addition, a cell operating in a U-band (e.g., SCell) is defined as UCell, and a carrier of UCell is defined as (DL / UL) UCC. The carrier / carrier frequency of the cell may mean the operating frequency of the cell (e.g., center frequency). A cell / carrier (e.g., CC) is collectively referred to as a cell.

Figure 9 illustrates a method of occupying resources within a license-exempt band. As an example of a license-exempt band operation operating in a contention-based random access scheme, a base station first carries out CS (Carrier Sensing) before data transmission / reception to check whether the current channel state of the UCell is busy or idle. For example, if there is a Clear Channel Assessment (CCA) threshold set by a predefined or higher-layer (eg, RRC) signaling, it may be considered busy or idle if an energy above the threshold is detected. If it is determined to be children, the base station can start signal transmission in the UCell. This sequence of processes is called Listen-Before-Talk (LBT).

In Europe, two LBT operations, named as Frame Based Equipment (FBE) and Load Based Equipment (LBE), are illustrated. The FBE includes a channel occupancy time (e.g., 1 to 10 ms), which means a time when the communication node can continue transmission when the channel is successfully connected (for example, 1 to 10 ms), and an idle period the idle period constitutes one fixed frame and the CCA is defined as the operation of observing the channel for the CCA slot (at least 20 μs) at the end of the idle period. The communication node periodically performs CCA on a fixed frame basis. When the channel is unoccupied, the communication node transmits data during the channel occupancy time. If the channel is occupied, the communication node suspends the transmission, Wait until the CCA slot.

On the other hand, in the case of LBE, the communication node first sets q∈ {4, 5, ... , 32} and then perform CCA for one CCA slot. If the channel is not occupied in the first CCA slot, the maximum time (13/32) q ms is secured and data can be transmitted. If the channel is occupied in the first CCA slot, the communication node randomly selects N ∈ {1, 2, ... , q} are stored as the initial value of the counter. Then, when the channel is not occupied by CCA slot while sensing the channel state in CCA slot unit, the value stored in the counter is decreased by one. When the counter value becomes 0, the communication node can transmit data by securing the maximum time (13/32) q ms.

실시예: SSB 구성 및 검출Example: SSB configuration and detection

10 shows an example of a frequency domain representation of a PSS, a SSS, and a PBCH constituting an SSB (Synchronization Signal Block, SS-Block). In NR system, PSS, SSS and PBCH can be defined as one SSB. Here, PSS and SSS are composed of 12RB (= 144RE) for different OFDM symbols, and 8 and 9 guard-carriers are included at both ends of the frequency domain, respectively. Further, the PBCH may be composed of two OFDM symbols and may be represented by PBCH ₁ and PBCH ₂ , respectively. PBCH ₁ and PBCH ₂ , and is transmitted over 24 RBs without guard-carriers. Here, the hatching of each block is used to represent PSS, SSS, and PBCH (PBCH ₁ , PBCH ₂ ), which are components of the SSB, and are expressed throughout the specification. However, in the case where a specific block is divided into a small block unit in a part, it means that the specific block can be physically divided (not continuous).

11 shows another example of the frequency domain representation of the PSS, the SSS, and the PBCH constituting the SSB. In the NR system, the SSB is finally determined to have the configuration as shown. The PBCH of FIG. 10 can be regarded as a logically bisected PBCH that spans three OFDM symbols in FIG.

FIG. 12 illustrates the configuration of a data resource element (RE) of a PBCH and a demodulation reference signal (DMRS) RE in a 1RB. Within one RB, the DMRS of the PBCH is transmitted across three REs, and the DMRS RE is located at equal intervals as shown.

The bandwidth of PSS and SSS can be defined as 2.16MHz * SCS / 15kHz according to SCS, and the bandwidth of PBCH ₁ and PBCH ₂ can be defined as 4.32MHz * SCS / 15kHz. For example, when SCS is 15kHz, 30kHz, 120kHz, 240kHz, and 480kHz, the bands of PSS / SSS and PBCH ₁ / PBCH ₂ can be expressed as follows.

if SCS = 15kHz

bandwidth: PSS & SSS = 2.16 MHz, PBCH1 & PBCH2 = 4.32 MHz

else if SCS = 30kHz

bandwidth: PSS & SSS = 4.32 MHz, PBCH1 & PBCH2 = 8.64 MHz

else if SCS = 120kHz

bandwidth: PSS & SSS = 17.28 MHz, PBCH1 & PBCH2 = 34.56 MHz

else if SCS = 240kHz

bandwidth: PSS & SSS = 34.56 MHz, PBCH1 & PBCH2 = 69.12 MHz

else if SCS = 480kHz

bandwidth: PSS & SSS = 69.12 MHz, PBCH1 & PBCH2 = 138.24 MHz

13 illustrates the configuration of the SSB. One SSB is configured over four OFDM symbols, and the order of transmission for each OFDM symbol in the SSB may be PSS, PBCH1, SSS, PBCH2. Here, PSS and SSS use the same RB (Resource Block) position, and PBCH1 and PBCH2 use the same RB position. However, since PSS and SSS are transmitted over a smaller number of RBs than PBCH, only 12RBs except 6RBs at both ends are used as compared with PBCH.

The SSBs described above are defined for licensed carriers / bands (Licensed-band, L-band). However, the SSB for the L-band is limited by the transmit power per frequency (e.g., maximum / minimum transmit power per 1 MHz) and the occupied band (e.g., transmit power per 1 MHz) of the license- Signal occupies a bandwidth of at least X-GHz) and may not be suitable to support effective LBT procedures.

Therefore, the present invention proposes an SSB configuration suitable for a U-band. In the present invention, the SSB configuration may vary depending on the frequency of the U-band (e.g., the 5 GHz band or the 60 GHz band). Also, the configuration of the SSB may vary depending on the operation mode (e.g., SA (standalone) or NSA (non-standalone) mode) of the NR in the U-band.

Hereinafter, the present invention describes a PBCH configuration method divided into a time domain configuration method and a frequency domain configuration method. In addition, according to the present invention, the U-band SSB is divided into three types (SSB of 1, 2, and 4 OFDM symbol structures) according to the number of OFDM symbols of SSB composed of PSS, SSS and PBCH. In addition, the present invention proposes a case where one or more SSBs exist in a U-band, and also proposes a power control according to the sub-block size / interval of the PBCH, PSS, and SSS. On the other hand, unlike PSS and SSS which are composed of sequences, PBCH can be different from L-band PBCH resource allocation because it can be composed of data RE and DMRS. Also, the SSB is largely divided according to the number of OFDM symbols constituting the SSB, and the applicable techniques may be different depending on the number of OFDM symbols used. Therefore, in the present invention, the U-band PBCH will be described first, and respective techniques according to the number of OFDM symbols occupied by the SSB will be described. The SSB proposed in the present invention can be applied not only to the U-band but also to the system using the L-band, and the same structure can be applied to values other than the SCS. Further, although the present invention is described based on the NR system, the present invention can also be applied to the SSB (configuration) of another system.

Hereinafter, the U-band SSB refers to a newly proposed SSB (configuration) for a license-exempt band in the absence of any description. The structure of the U-band SSB may be based on FIGS. 10 and 11. FIG. An L-band SSB may refer to an existing SSB (configuration) defined for a license band (see Figs. 10-13), unless otherwise stated. The U-band refers to a license-exempt carrier / band, and the L-band refers to a license carrier / band.

1. PBCH의 구성1. Configuration of PBCH

In the present invention, the PBCH configuration method is divided into a time domain configuration method and a frequency domain configuration method, but they can be combined with each other. That is, the time domain configuration method and the frequency domain configuration method can be applied to each other. In addition, the contents related to the sub-block configuration method and the DMRS arrangement of PBCH ₁ and PBCH ₂ can also be applied to each other. Also, since it is obvious that each of the other proposals can be cross applied under conditions that do not conflict with each other, all proposals can be cross-applied without special conditions and explanations. However, for example, " a method of transmitting PBCH ₁ and PBCH ₂ to different OFDM symbols " and a " method of transmitting PBCH ₁ and OFDM symbols synchronized with PBCH ₂ " In this case, the former and latter may be selectively applied depending on the specific conditions (e.g., NSA and SA conditions, etc.).

[Method # 1] A method of transmitting PBCH ₁ and PBCH ₂ to the same OFDM symbol (FIG. 14)

PBCH ₁ and PBCH ₂ can be transmitted in the same OFDM symbol FDM

PSS and SSS may be located between PBCH ₁ and PBCH ₂ when a PBCH is transmitted on the same OFDM symbol as PSS and SSS

○ When both PSS, SSS and PBCH are transmitted on different OFDM symbols, PBCH SCS may be twice as small as SCS of PSS and SSS

For example, in case of PSS, SSS, and PBCH, the OFDM symbol interval of the PSS and the SSS may be twice shorter than the OFDM symbol interval of the PBCH, respectively.

○ The order of frequency domain assignment of PBCH ₁ and PBCH ₂ may be PBCH ₁ -PBCH ₂ order or PBCH ₂ -PBCH ₁ order

FIG. 14 illustrates a PBCH structure that is continuously allocated in the frequency domain of the same OFDM symbol. The proposed method is independent of the frequency domain resource allocation method (e.g. offset value K _{0 in} FIG. 14) between PBCH ₁ and PBHC ₂ . If the PBCH is not sent on the same symbol as the PSS and the SSS, the SCS of the PSS and the SSS and the SCS of the PBCH may be different from each other.

[Method # 2] A method of transmitting PBCH ₁ and PBCH ₂ to different OFDM symbols (FIG. 15)

PBCH ₁ and PBCH ₂ can be transmitted in different OFDM symbols separated by N ₀

N ₀ may be 0, where PBCH ₁ and PBCH ₂ may be transmitted over adjacent OFDM symbols

○ ₀ N is greater than 1, in the OFDM symbol (s) between ₀ and PBCH PBCH _one PSS, and / or SSS is inserted can be transmitted

○ PBCH SCS can be twice as large as SCS of PSS and SSS when PBCH is transmitted in PSS and SSS and other OFDM symbols

- For example, PSS and SSS is sent in the same OFDM symbol, PBCH ₁ and PBCH ₂ is an OFDM symbol interval OFDM symbol interval of PSS / SSS in each PBCH ₁ and PBCH ₂ when transmitted from different OFDM symbols than each May be twice as short

○ OFDM symbol allocation order of the PBCH and the PBCH ₁ ₂ is PBCH -PBCH ₁ or ₂ in order, PBCH ₂ -PBCH May ₁ sunil

FIG. 15 illustrates a PBCH structure that is continuously allocated in the frequency domain over different OFDM symbols. In this way can the OFDM symbol between PBCH ₁ and PBHC ₂ N ₀ is independent of the frequency domain resource assigned offset values K ₀ between PBCH ₁ and PBHC ₂ of Figure 15, PBCH ₁ and PBHC ₂ are each the same position in the frequency domain K ₀ may be ignored or defined as a negative value of " PBCH ₁ or RE number of PBCH ₂ ". Also, the maximum value of N ₀ can be limited to two. If the PSS and SSS of the U-band SSB are transmitted in the same OFDM symbol, the maximum value of N ₀ may be limited to one. Also, if the PBCH is not transmitted on the same symbol as the PSS and the SSS, the SCS of the PSS and the SSS and the SCS of the PBCH may be different from each other.

In the U-band, there may be regulations related to the regulation related to the transmission power per frequency and the minimum value of the frequency band occupied by the transmission signal. In order to satisfy this, the signal transmitted in the U-band occupies the widest frequency band, and the transmission power per specific frequency unit needs to be limited to a range of not less than a predetermined value. Therefore, the SSB of the U-band needs to be designed to occupy the widest possible area in the frequency domain. As a method for this, it is possible to allocate consecutively in the frequency domain while increasing the SCS of the PSS and the SSS and the PBCH, which is all possible with the structure of the above-mentioned proposals. Alternatively, the SSB can be allocated discontinuously in the frequency domain, with some intervals. However, it is not desirable to transmit discontinuously in the frequency domain because the PSS and the SSS are designed in a specific sequence among the components of the SSB. Therefore, a method of discontinuously allocating the PBCH composed of the data RE and the DMRS RE in the frequency domain can be considered. The following suggests a method for this.

[Method # 3] A method of discontinuously allocating the PBCH in the frequency domain (FIGS. 16 to 19)

■ How to assign PBCH ₁ and PBCH ₂ discretely in the frequency domain

14 and 15, a method of not transmitting PBCH ₁ and PBCH ₂ in the same frequency domain

- PBCH ₁ and PBCH ₂ can not be transmitted in the same frequency domain when PBCH ₁ and PBCH ₂ are always transmitted in the same OFDM symbol as in FIG. 14

However, the density of DMRS (ie, [PBCH DMRS RE number] / [PBCH data RE number]) within PBCH ₁ and PBCH ₂ may be higher than the density of the L-band

- However, the SCS of the PBCH may be larger than the PBCH SCS of the L-band.

■ PBCH ₁ and the method of allocating PBCH ₂ respectively discontinuously in the frequency domain (for example, 16 to 19)

₁ ○ PBCH and the PBCH ₂ each B sub-divided into blocks, ₁ PBCH of the sub-method for a frequency shift by k coming from block _1-block of the sub-PBCH ₂

○ PBCH and the PBCH ₁ ₂ k is ₀ can be generated by offset, k is ₀ can be defined as k ₁ and a specific relation formula

○ Frequency domain location of sub-block can be set differently for each cell ID group

- This can be used for purposes similar to PBCH DMRS in the L-band using different frequency shifts according to cell ID

Here, the unit of the sub-block is

- may be larger than RB and may be an integer multiple of data (eg, PDCCH, PDSCH, PUCCH, and / or PUSCH) resource allocation units (eg Resource Block Group, RBG) If there are more than two resource allocation methods (LTE, for example, resource allocation type0, type1, type2, etc.), a default resource allocation method can be specified, and the unit of the sub-block is an integer of the basic resource allocation unit of the default resource allocation method It can be defined in units of times, or can be defined as an integer multiple of PRB (Precoding Resource Block), which is a precoding unit.

- RB. In this case, the unit of the sub-block can be set in consideration of regulation such as transmission power per bandwidth. Also, sub-block units (e.g., bandwidth or RE) may vary depending on the SCS and frequency band.

○ May be designed to include at least one DMRS RE per sub-block. Accordingly, the DMRS frequency density of the U-band may be higher than the DMRS frequency density of the L-band. For example, the number of valid data REs contained in a PBCH may be the same in both the U-band and the L-band, but the number of REs in the DMRS may be greater than the L-band in the U-band

- Depending on the number of DMRS REs increased, the frequency shift of the DMRS RE (the frequency shift of the DMRS RE varies depending on the cell ID in the L-band) may be reduced

- Frequency shift of DMRS RE is only possible in sub-block

■ Frequency shift k ₀ and k ₁ units (Hz or integer value) can be defined as

Here, k ₀ and k ₁ are

- an integer multiple of the SCS of the SSB or U-band PBCH,

- May be an integer multiple of data (eg PDCCH and / or PDSCH and / or PUCCH and / or PUSCH) resource allocation units (eg RBG). Resource allocation method (for LTE example, the resource allocation type0, type1, type2, etc.) If there's more than one is, and can specify a default resource allocation method, k ₀ and k ₁ is an integer from basic resource allocation unit in the default resource allocation method Defined in units of times, or

- It can be defined as integer multiples of PRB, which is the unit of precoding.

○ In a multiple relationship of k _0, k ₁ according to the SCS will be different (for example, that the SCS is ₀ and k = 2k ₁ in the case of 15kHz, the SCS can be in case of 120kHz k ₀ = k ₁₎

If the entire U-band can be defined in C bands (eg, CC or BWP (bandwidth part)), then k ₀ is defined such that PBCH ₁ and PBCH ₂ are not included in the same band as PSS and SSS Yes. Here, BWP means a sub-band consisting of consecutive frequency resources in a cell / CC (e.g., a plurality of consecutive RBs).

○ k ₀ and k ₁ may not always be fixed values in the U-band

To avoid inter-cell interference, it can be defined to have different values depending on the cell ID.

- can be defined to have different values between SSBs within the U-band SSB transmission period for the time synchronization of the U-band SSB (OFDM symbol location of SSB) within the radio frame (or subframe or slot)

If the sub-block units of PBCH ₁ and PBCH ₂ are smaller than the RB units, the position of the sub-blocks within the RB may also be set differently for the same reasons (inter-cell interference or time synchronization)

K ₀ and k _{1, which} represent the frequency domain offset in the above description and FIGS. 16-19, are parameters presented to show that the frequency domain assignments of PBCH ₁ and PBCH ₂ are different. The exact definition of k ₀ and k ₁ varies However, for the convenience of description, it is described based on the definition exemplified in the drawing. On the other hand, the difference between FIG. 16 and FIG. 17 is whether PBCH ₁ and PBCH ₂ are designed to have a constant offset or be designed to have different offset values around a certain interval. Also, the difference between FIG. 18 and FIG. 19 is whether PBCH ₁ and PBCH ₂ will be divided into sub-blocks within a specific area, respectively, or each sub-block will be configured to cross.

[Method # 4] How to set the location and density of DMRS RE in PBCH

■ PBCH DMRS density of L-band SSB may be higher than PBCH DMRS density of L-band SSB. PBCH The DMRS density can be defined as [PBCH DMRS RE number] / [PBCH data RE number] within RB.

○ U-band PBCH The DMRS density can be defined as a different value depending on the frequency band, reflecting the frequency selectivity characteristic of the radio channel.

○ PBCH DMRS density may be different from L-band when only DMRS is transmitted for U-band measurement and LBT without data RE in PBCH

The U-band system can have higher DMRS density in the frequency domain than the L-band, since the U-band system does not have to consider the high-speed movement characteristic of the UE relatively as compared with the L-band. On the other hand, Can have DMRS density

■ PBCH DMRS frequency shift set may be different from PBCH DMRS frequency shift set of L-band SSB

Frequency shift of U-band PBCH DMRS can be determined by cell ID and / or time resources (slot and / or symbol) and / or SSB index

The PBCH DMRS frequency shift set may differ from the L-band if only the DMRS is transmitted for the U-band measurement and the LBT without the data RE in the PBCH

If the U-band is in non-standalone (NSA) mode rather than in standalone (SA) mode (mode that can operate without base station assistance via the L-band), (1) PBCH is omitted, (2) Data is omitted, or (3) the DMRS of the PBCH is set to the same specific value so that the SSB can be configured

○ PBCH can be transmitted only by DMRS for U-band measurement and LBT. In this case, the PBCH DMRS density may be higher than the PBCH DMRS density when the U-band is in the SA mode, and the DMRS may be additionally transmitted only to the position of the data RE so that the frequency shift of the DMRS RE is the same as the L-

○ PBCH Among the information constituting DMRS, slot-time related information can be delivered from PCell. In this case, the U-band PBCH DMRS can be set to the same value in a certain cell (this can also be used for reducing complexity such as U-band neighbor cell interference measurement)

■ DMRS density and frequency shift of PBCH ₁ and PBCH ₂ may be different

○ PBCH when the _first time is the most advanced position as in the SSB, the DMRS density of the PBCH can ₁ is higher than the DMRS density of the PBCH ₂ in order to help the like (Automatic Gain Control) of the terminal AGC

○ PBCH When _divalent latest position in time in SSB, in consideration of the transition (transient) period required for the sweeping beam of the base station that the DMRS density of the PBCH may be higher than the _second DMRS density of ₁ PBCH. This is assuming the case where the beam sweeping cheonyi time caused / allowed by the PBCH _1, that if the contrary the DMRS density of the PBCH ₁ be higher than the DMRS density of the PBCH ₂

In the L-band, the NR system needs to be designed so that the DMRS frequency shift of SSB can have different values depending on the cell ID, the beam ID (SSB), the slot index, etc., in consideration of inter-cell or inter-beam interference. However, since a specific base station or a terminal occupies a wireless channel (e.g., a frequency resource) at a specific time by performing an LBT in a U-band, a frequency shift of the L- . &Lt; / RTI > In addition, when the PBCH data RE is omitted, the DMRS frequency shift set and density can be varied to meet the regulation related to the transmit power per frequency. In addition, since the U-band may not consider the high-speed mobility of the UE relatively high, PBCH ₁ and PBCH ₂ may not transmit the DMRS at the same frequency location, frequency-shift the frequency by a specific interval, As shown in FIG.

[Method # 5] Repeated transmission of PBCH in the frequency domain

PBCH can be repeated N times in the frequency domain

The default N value can be set for the UE in the initial connection procedure, and the base station can repeatedly transmit the PBCH in the frequency domain with a value equal to or larger than the default N

If N is different from the default value, the base station can inform the UE of the N value through the high-level (eg, RRC) signaling, and the UE not assigned the N value can attempt to detect the PBCH based on the default value has exist

○ The number of PBCH DMRS RE increases in proportion to the value of N, and the UE can estimate the channel by assuming QCL (quasi co-located) for N times extended DMRS

Even if N increases, the sequence mapped to PBCH DMRS RE is the same (that is, the sequence of the PBCH DMRS RE included in at least the default N region is constant regardless of N, even if the PBCH is mapped by N times extended)

When PBCH is mapped by N times, each PBCH data can be scrambled and mapped (the DMRS can be mapped to a N times extended sequence rather than a scrambling method)

The order in which each PBCH data is mapped to the PBCH RE may vary when PBCH is mapped by N times of extension

As a method of transmitting the PBCH in the wide band, there may be a method of repeating the PBCH in the frequency domain. This may improve the PBCH SNR of the receiver to increase the PBCH decoding coverage. At this time, if the number of times of repetition of the PBCH (N) can be variably applied, the base station should repeatedly transmit the PBCH more than the minimum number of repetitions (e.g., the default number) It is possible to assign N to the terminal that is larger than the default N. [ When the PBCH is determined N times, the PBCH DMRS can also be extended transmission in proportion to N. [ The UE can perform channel estimation assuming that all of the PBCH DMRS extended N times are assumed to have a QCL relationship. That is, the base station does not apply independent / additional beamforming to the N times determined PBCH region. On the other hand, a signal repeated N times in frequency may appear in a zero-insertion form in the time domain, which may have disadvantages such as increasing a peak-to-average power ratio (PAPR) of a transmitted signal have. Therefore, scrambling needs to be applied to each PBCH that is mapped by N times of extension. At this time, the scrambling sequence / code applied to each PBCH may be applied differently for each RE. The DMRS can prevent the zero - insertion effect by the DMRS sequence extension method rather than the scrambling method. By eliminating the zero-insertion effect, the order of the PBCH data-to-RE mapping can be different for each PBCH repetition (in the frequency domain).

2. SSB의 구성2. Configuration of SSB

In the present invention, the U-band SSB can be roughly classified into three types (SSB of 1, 2, and 4 OFDM symbol structures) according to the number of OFDM symbols. The sub-element descriptions of the respective methods can be combined with each other, and can be applied in combination with each element technology of the above-described PBCH configuration.

[Method # 6] SSB of four OFDM symbol structures (FIGS. 20 to 21)

How to allocate frequency resources by frequency shifting PSS, SSS and PBCH

○ How to frequency shift each signal and channel by k ₀ and k ₁

■ Frequency shift k ₀ and k ₁ , k ₂ units (Hz or integer value) can be defined as

Here, k ₀ and k ₁ , k ₂ are

- an integer multiple of the SCS of the SSB, or

- May be an integer multiple of data (eg PDCCH and / or PDSCH and / or PUCCH and / or PUSCH) resource allocation units (eg RBG). Resource allocation method (for LTE example, the resource allocation type0, type1, type2, etc.) If there's more than one is, and can specify a default resource allocation method, k ₀ and k _1, k ₂ is a basic resource allocation method default resource allocation Is defined as an integer multiple of units, or

- The multiple relationship of k ₀ , k ₁ , k ₂ may vary depending on the SCS (eg, k ₀ = 2 k ₁ = k ₂ when SCS is 15 kHz and k ₀ = k ₁ = k ₂ )

If the entire U-band can be divided into C bands (eg, CC or BWP), k ₀ is defined so that PSS and SSS are included in the same band, and k ₁ is defined to be included in the other bands Can

■ When the U-band operates in NSA mode, (1) PBCH may be omitted, or (2) only the data of PBCH may be omitted and SSB may be configured

If both PBCH data and DMRS are omitted, PSS and SSS are mapped to consecutive OFDM symbols, and U-band SSB can be composed of 2 symbols.

○ PBCH If the OFDM symbol is not omitted, the data in the PBCH can be replaced by a known sequence (eg, a signal and sequence similar to the PBCH DMRS).

- The base station can transmit the known sequence together with the existing PBCH DMRS at the same time so that they do not overlap with each other in the frequency domain, or transmit the known sequence to all RE positions of the PBCH, omitting the existing PBCH DMRS transmission

The order of the OFDM symbols (PSS, SSS, PBCH ₁ , PBCH ₂ ) of the U-band SSB may be different from the order of OFDM symbols of the L-band SSB

The temporal OFDM symbol mapping order may be PBCH ₁ , PSS, SSS, PBCH ₂ or PBCH ₁ , PBCH ₂ , PSS, SSS. Unlike the L-band, the PBCH needs to be transmitted before the PSS / SSS for the AGC of the UE in the U-band where the SSB can be transmitted intermittently / opportunely.

The OFDM symbol mapping order can be determined in consideration of the transition time required for the AGC of the SSB of the UE and the beam sweep of the BS, and may have a different order depending on the frequency band of the U-band and the SCS of the SSB.

In the case where the proposed four OFDM symbols SSB are transmitted with the PBCH omitted in the NSA environment, it is difficult to omit OFDM symbols for PBCH transmission. This is not suitable for other systems or other users' LBTs. In such a situation, instead of omitting the PBCH OFDM symbol, the PBCH is used for U-band measurement and LBT, AGC etc. of the terminal in a known sequence Sequence) to be transmitted. In this case, the BS may transmit the known sequence together with the existing DMRS so that they do not overlap with each other in the frequency domain, or may transmit the known sequence to all RE positions of the PBCH, omitting the existing DMRS transmission. In addition, the order of transmission of the SSB (PSS, SSS, PBCH ₁ , PBCH ₂ ) may differ from that of the L-band. In addition, the frequency domain resource is PBCH PBCH ₁ and ₂ occupied by each of which may be set to the value k ₀ is equal to or similar to the sum of the frequency-domain resources in the PSS and SSS.

In Figure 20-21 placing all the other frequency domain, the PSS and SSS, PBCH, and in order to satisfy regulations relating to the maximum bandwidth to the transmission signal in the band U- occupy, depending on the value of k ₀ and k ₁ PSS And the SSS and the PBCH may partially overlap in the frequency domain. In addition, FIG. 21 can also be used for inter-cell interference minimization such as DMRS frequency shift of L-band among k ₂ sub-blocks. That is, the sub-blocks of the PBCH may be set to occupy different frequency regions for each specific cell ID group.

In interpreting the Power Spectral Density (PSD) regulation associated with the constraint on the transmit power per specific bandwidth in the U-band, the transmit power over the OFDM symbols (corresponding to a defined specific time) It is possible to consider a method of boosting the transmission power of each OFDM symbol. For example, when the PDS regulation is defined as the average power of four OFDM symbol intervals in FIGS. 20 to 21, PSS, SSS, and PBCH transmitted for each OFDM symbol have average powers to be transmitted in four OFDM symbols, You can use it all. This can be applied to the SSB of the 2 OFDM symbol structure in the same manner.

If the PBCH transmission in the above SSB structure is omitted, the PSS and SSS of another SSB (e.g., next SSB) in the OFDM symbol to which the PBCH should have been transmitted may be transmitted instead. If the PBCH transmission is omitted when PSS: PBCH ₁ : SSS: PBCH _{2 in the} order of OFDM symbol transmission in the 4 OFDM symbol SSB is chronologically ordered, the OFDM symbol transmission order is PSS: PSS ': SSS: SSS' . PSS 'and SSS' refer to PSS and SSS of another SSB. Also, the transmission order of the SSB may be PSS: SSS ': SSS: PSS'.

[Method # 7] SSB of 3 OFDM symbol structure (FIG. 22)

3 OFDM symbol In SSB, PSS and SSS are transmitted in one OFDM symbol in FDM form, and PBCH ₁ and PBCH- ₂ can be located before / after PSS / SSS OFDM symbol. Here, the PSS and the SSS do not intersect in the interleaved type or the staggered type. PBCH ₁ and PBCH ₂ may be mapped on sub-block basis in the frequency axis as in [Method # 6], and the sub-blocks of the PBCH may occupy different frequency regions for each cell ID group. When the PBCH is divided into sub-block units, PSS and SSS may also be mapped on the frequency axis by k ₀ , and k ₀ may be a value corresponding to RBG or PBG unit. By arranging the PSS and the SSS between the PBCH ₁ and the PBCH ₂ in this way, it is possible to improve the performance of estimating the carrier frequency offset (CFO) of the UE. For example, the UE can estimate the CFO based on the DMRS of each PBCH symbol separated by 2 OFDM symbols. Such a CFO estimation method is characterized in that the estimation performance is improved in proportion to the interval between the OFDM symbols transmitting the DMRS have. However, in order to use such a CFO estimation method, since the DMRS included in PBCH ₁ and PBCH ₂ must be transmitted to the same frequency position, sub-blocks of PBCH ₁ and PBCH ₂ are transmitted in frequency Can not be mapped completely independently, and are limited to use the same sub-block positions with each other.

[Method # 8] The SSB of two OFDM symbol structures (FIGS. 23 to 27)

How to allocate frequency resources by frequency shifting PSS, SSS and PBCH

○ How to frequency shift each signal and channel by k ₀ and k ₁

Depending on the value of k ₀ , the PSS and the SSS may use the same resources in the frequency domain or may be transmitted in such a way that only some of the regions overlap.

Here, k ₀ and k ₁ , k ₂ are

- an integer multiple of the SCS of the SSB, or

- It may be an integer multiple of a resource allocation unit (eg, Resource Block Group (RBG)) of data (PDCCH and / or PDSCH and / or PUCCH and / or PUSCH) Resource allocation method (for LTE example, the resource allocation type0, type1, type2, etc.) If there's more than one is, and can specify a default resource allocation method, k ₀ and k _1, k ₂ is a basic resource allocation method default resource allocation Is defined as an integer multiple of units, or

The order (PSS, SSS, PBCH ₁ , PBCH ₂ ) in the time / frequency domain of the U-band SSB may differ from the order in the time / frequency domain of the L-band SSB

Considering the possibility that the PBCH may be omitted in the NSA mode unlike the L-band SSB, FDM of PSS and PBCH ₁ and FDM of SSS and PBCH ₂ are performed so that a gap interval does not occur in the SSB, . Of course, PBCH ₁ and PBCH ₂ , which are PSS and SSS and FDM, may be changed to PBCH ₂ and PBCH ₁ , and the SSS may be configured to be mapped to an OFDM symbol temporally ahead of the PSS. In the case of Fig. 23 ~ 27 k ₂ is 0, it can be interpreted as the PBCH and the PBCH ₁ ₂ contiguous allocation structure in the frequency domain. Also, in the drawing, the PSS / SSS and the PBCH may be set to overlap. For example, the SSS may overlap some or all of PBCH ₂ , which is possible if some k parameters are negative.

[Method # 9] SSB of one OFDM symbol structure (FIG. 28)

How to allocate frequency resources by frequency shifting PSS, SSS and PBCH

○ How to frequency shift each signal and channel by k ₀ and k ₁

Here, k ₀ and k ₁ , k ₂ are

- an integer multiple of the SCS of the SSB, or

○ if the U- band, the entire band may be defined as one divided band (for example, CC or BWP) C, PSS and SSS may be a k ₀ defined to be included in the same band, such that k ₁ is included in the other band Can be defined

Unlike the L-band SSB, the SSB needs to be configured as short as possible because the U-band can occupy the wireless channel only for a short time in case of LBT success. This can be an important feature to enable the base station to transmit all SSBs in a short period of time, and the SSB of one OFDM symbol structure may be opportunely used depending on the LBT condition (eg CCA) at the base station. In other words, if only a short time LBT is performed, or if there is not enough time to occupy the wireless channel or if SSB should be transmitted continuously over a certain number of times, another format (eg, [Method # 6], [Method # 8], etc.), the SSB of one OFDM symbol structure can be transmitted opportunistically even if a U-band SSB is defined. In FIG. 28, when k ₂ is 0, it can be interpreted as a PBCH ₁ and a PBCH ₂ structure continuously allocated in the frequency domain.

When a base station divides a wideband U-band into a plurality of CCs for transmission / reception, according to the SSB proposal, the components of the SSB may not always be transmitted only to the same CC. For example, the k parameter may be set such that both PSS and SSS, PBCH ₁ , and PBCH ₂ are transmitted to different CCs. In such a case, the frequency (e.g., frequency raster, raster offset, etc.) (or CC) of the SSB expected by the terminal for initial connection can be defined as the frequency (or CC) at which the PSS is transmitted. In addition, different SSBs may be transmitted in CC-level FDM for each CC at the same time.

3. 추가적인 기능 제공을 위한 SSB3. SSB for additional functions

In the U-band, a signal can be continuously transmitted occupying a radio channel opportunistically for a specific time (for example, the channel occupancy time in FIG. 9), and such an interval can be called a burst. It can be assumed that there is a burst of data, which is a section for transmission of data (e.g., PDCCH, PDSCH, etc.), and a measurement burst for measurement of the terminal. At this time, the SSB can be transmitted in both the data burst and the measurement burst, and different SSB formats (the SSB configuration scheme proposed above) can be used depending on the burst type in which the SSB is transmitted. In addition, different SSB formats can be used depending on the purpose of using SSB even in a burst of the same type. For example, an SSB of one OFDM symbol structure may be used to detect beam tracing of the terminal at the start and / or end of the DL burst (e.g., seeking a new best beam or tracking or refining for a transmit beam other than the transmit beam of the data burst) (Eg, a process for refinement, etc.).

[Method # 10] How to support more than one SSB configuration

■ U-band SSBs may have different structures depending on the burst type in which SSBs are transmitted.

○ The number of OFDM symbols in the SSB transmitted to the measurement burst and the number of OFDM symbols in the SSB transmitted to the data burst may be different.

○ The SSB transmitted to the measurement burst includes the PBCH, but the PBCH may not be transmitted to the SSB of the data burst, and vice versa.

○ The SCS of the SSB transmitted to the measurement burst and the SCS of the SSB transmitted to the data burst may be different.

■ U-band SSB can transmit SSB with different structure depending on purpose for use even within specific burst types

When SSB is transmitted from the first OFDM symbol of the data burst (or excluding from the training symbol for AGC and burst detection) and the OFDM symbol (or slot, etc.) within the data burst, And " when the data burst is transmitted from the last OFDM symbol of the data burst to the end of the data burst ", the SSB formats may be different from each other

○ SSB format may include SCS and / or PBCH inclusion and / or frequency domain.

■ SSBs that are transmitted additionally (aperiodically) for a specific purpose may differ from SSBs (eg, SSBs used for RRM purposes) that are sent for cell detection and cell reception power or quality measurements of the UE

The presence and additional transmission of additional SSBs to the terminal with a specific signal within that burst for a specific purpose (eg, for finding a new best beam or for tracking or refinement of a transmit beam other than the transmit beam of the data burst) Method, etc.

The additional transmitted SSB for a specific purpose may be transmitted at a different location than the SSB's promised frequency location (eg, the raster offset of the SSB where the raster offset is transmitted periodically) May vary)

○ PBCH may be omitted in SSB if it is used for this purpose

○ In case of using for this purpose, PSS of SSB and SCS of SSS may be different from PSS included in SSB which is transmitted periodically and SCS of SSS

■ When the Remaining System Information (RMSI) is transmitted in the same burst as the SSB (for example, in a subframe / slot set that is continuously transmitted without a gap after the LBT succeeds) and in the case of a burst , SCS) can be different

○ RMSI and SSB can be transmitted in TDM or FDM. At this time, if the SCS of the SSB is 60 kHz, the frequency resources for performing RMSI and FDM may not be sufficient. Therefore, if RMSI and SSB are FDM, SSB can be transmitted with SCS of 15kHz or 30kHz, otherwise SSB of 60kH SCS can be transmitted.

In other words, when SSB is transmitted by setting a specific window and period for cell detection and RRM of a terminal in one cell, (i) the annoyance of SSB transmitted in the window, (ii) And (iii) SSMs in the period in which the RMSI is transmitted (or SSB transmitted with RMSI) may be different, even though they are transmitted within the window.

In addition, the SSB transmitted in a cell that does not transmit an RMSI (e.g., an NSA mode cell) may differ in the annotation of the SSB transmitted in a cell transmitting the RMSI (non-periodically). For example, the SSB SCS when not transmitting an RMSI may be larger than if not.

In addition, the annotation of the SSB transmitted in the same burst as the RMSI may be set equal to the RMSI numeration.

■ If the terminal can expect SSB (eg, having a paging channel and QCL relationship) with TDM prior to transmission (within the same burst) or with FDM at the same time prior to transmission of the paging channel (PDCCH and / or PDSCH) Can be different from that of the SSB transmitted regardless of the paging channel, as in the case of " a case where the RMSI and the SSB are simultaneously transmitted ". Accordingly, the SS can differently assume the SSB when SSB is detected in PO (Paging Occasion) and SSB when SSB is not detected.

When the SSB associated with the TDM or the FDM at the same time is transmitted prior to the paging channel transmission, the annunciation of the corresponding SSB can be set equal to the paging channel's journalism.

The number of SSBs in a cell can be set differently depending on the purpose / use of the SSB. SSB applications may be as follows. Here, the SSB usage is not determined by the UE but may be limited to the case where the BS further configures the SSB for the following purposes. Also, the annoyance of SSBs used for the following purposes may be different from SSBs (e.g., SSB for initial acquisition) that are generally transmitted for cell identification in a serving cell, even though they are identical to each other.

Measurement reference resources for serving cell RRM / Radio Link Management (RLM)

Measurement reference resources for neighbor cell RRM

Resources for time / frequency tracking of terminals

Signals or resources used for downlink burst detection

Resources used for beam tracking

The resources used to direct the RMSI transmission (eg SSB transmitted in the same burst as the RMSI)

○ Resources used to direct paging transmissions (eg, SSBs transmitted within the same burst as paging)

4. PSS/SSS와 PBCH의 뉴머놀로지 및 서브-블록 크기/간격에 따른 송신 전력4. Transmit power according to the amplitude and sub-block size / interval of PSS / SSS and PBCH

The SSB scheme proposed in the present invention may be different between the SCS of the PSS / SSS and the SCS of the PBCH. Accordingly, the transmission power may be different between the PSS / SSS and the PBCH having different amplitudes in order to satisfy the regulation on the transmission power per specific bandwidth. For example, if the SCS of the PBCH is twice as large as the SCS of the PSS / SSS, the transmit power per tone (frequency tone) of the PBCH may be twice as much as the transmit power per tone of the PSS / SSS.

[Method # 11] Transmission power according to PSS / SSS and PBCH

The transmit power per tone of the PBCH and the PSS / SSS can be different, which can be defined by a special relationship with the signaling and channel annihilation

If the components of the SSB (PSS, SSS, PBCH) have different SCSs between bursts and / or within a burst within the U-band, the transmit power per tone of each component may be different

The previously proposed method of " 1. Configuration of PBCH " and " 2. Configuration of SSB " may have different amplitudes and transmit powers

The transmission power may also be different depending on the sub-block number / size of the proposed PBCH and the parameters B and k related to the PSS, SSS, and PBCH interval. Taking a sub-block of a PBCH as an example, the transmit power per sub-block may be smaller than when the size of the sub-block is small, when the size of the sub-block is large (i.e., parameter B is small). In addition, the transmission power per sub-block may be even greater when the sub-block spacing is smaller than the transmission power per sub-block when the sub-block spacing is large. In order to maximize the transmission power per sub-block within the range satisfying the PSD regulation, the PSS and the SSS transmitted in one block are each sub-block, and the transmission power is adjusted between the PSS, the SSS and the PBCH .

[Method # 12] Transmission power according to sub-block interval

The transmit power per tone of PBCH and PSS / SSS can be different, which can be defined in terms of the sub-block size and sub-block size of each signal and channel.

If the SSBs have different sub-block sizes and / or intervals between bursts and / or within a burst in the U-band, the transmit power per tone of each component (PSS, SSS, PBCH) of the SSB is different Can

The terminal is limited such that the offset of the oscillator does not exceed a certain value (e.g., 0.1 ppm) before transmitting the random access signal. For this, the UE must be able to estimate the CFO with high accuracy using the downlink signal of the base station, which is generally determined by the structure of the downlink synchronization signal (SSB). The most widely used technique for CFO estimation is to use the same signal repeatedly received. To this end, a specific OFDM symbol or an entire OFDM symbol of the SSB may be defined to have a repetition property in the time domain. For example, the OFDM symbol may be composed of one CP + repeated symbol. That is, not the OFDM symbol composed of CPs transmitted once before every symbol, but the same symbol is repeated several times, and only one CP is added to the front of all repeated symbols. Here, the symbol denotes a data part or useful duration of an OFDM symbol. Repeated transmission of symbols may be implemented via comb-type mapping in the frequency domain. The symbol configuration can be used not only to improve the CFO estimation performance of the UE but also to perform SSB detection while changing SSB transmitted from a base station in a specific beam direction to a UE in various directions in a short time unit .

[Method # 13] Repeated transmission of SSB

The SCS of the SSB may be larger than the SCS of the data burst, and may be configured in the time domain in the frequency domain in a comb-type mapped form

One OFDM symbol belonging to SSB can be composed of one CP and a number of repetition symbols

If the SSB is composed of two or more OFDM symbols, it can be composed of one CP and multiple repetition symbols for OFDM symbols including PSS and SSS.

The CP length may be different from the length of the newly constructed SSB and the CP length of the L-band SSB to match the symbol or slot boundary according to the data SCS

4. SSB의 재구성 및 배치4. Reorganization and Placement of SSB

In the NR system, SSB is defined only for SCSs of 15 kHz, 30 kHz, 120 kHz, and 240 kHz, which are related to the frequency bands of the data SCS and NR systems. Referring to FIG. 29, in the band (L-band) lower than 6 GHz, SSB SCS is only available at 15 kHz or 30 kHz, and data SCS is allowed at 15 kHz, 30 kHz or 60 kHz. Also, in the band (L-band) higher than 6 GHz, the SSB SCS is only available at 120 kHz or 240 kHz, and the data SCS is only allowed at 60 kHz, 120 kHz or 480 kHz. In FIG. 29, each box represents an OFDM symbol, and numbers (0 to 13) at the top of the drawing represent OFDM symbol indexes in a slot based on 15 kHz SCS and 60 kHz SCS, respectively. In particular, in the case of the L-band, the reason why the 60-kHz SSB SCS is not used even when the data SCS is 60 kHz in the band lower than 6 GHz is that the 60-kHz data SCS is used specifically for Ultra-Reliable Low Latency Communication It is because it was expected. That is, in the band below 6GHz, NR systems are generally expected to provide 15kHz or 30kHz SCS based enhanced mobile broadband (eMBB) services, but delayed-sensitive services (eg U (R) LLC) It is expected that only 60kHz SCS data will be used to satisfy the delay requirement. On the other hand, a 60kHz data SCS may not be needed because the eMBB and URLLC services are not expected to be used simultaneously in the U-band. However, considering the environment in which the medium occupies an opportunity on the basis of LBT in U-band, large SCS may be more suitable for U-band. Thus, a data SCS of 60 kHz in the band below 6 GHz can still be used (for eMBB service provisioning). For this reason, the SSB SCS in the U-band needs to be newly defined up to 60 kHz as the data SCS.

[Method # 14] 60 kHz SCS-based SSB configuration and arrangement (Figure 30)

■ How to place SSBs consecutively on the time axis

A method of arranging SSBs composed of N OFDM symbols so that they are not configured over a boundary of 0.5 msec (for example, when N = 4 in FIG. 29, different SSB indexes are arranged adjacent to each other with a boundary of 0.5 msec)

- Even if there are fewer than 14 SSBs (maximum L) in 1 msec, there is no way to place L SSBs consecutively

L SSBs are arranged continuously for [Method # 7], [Method # 8], and [Method # 9], so that the specific SSB is not configured over the boundary of 0.5 msec

The reason why one SSB is arranged so as not to cross the boundary of 0.5 msec is because the CP length of the first OFDM symbol is different from the CP length of the remaining OFDM symbols within 0.5 ms every 0.5 msec. 30 shows SSB configuration and arrangement for 15 kHz, 30 kHz and 60 kHz SCS within 1 msec interval, and the width of each box represents the length of each OFDM symbol based on SCS. For convenience, the representation of the frequency axis is omitted. Each hatch is used to distinguish between different SSBs and does not mean the same SSB index. For example, 14 SSBs may exist within 1 msec based on a 60 kHz SCS, and each SSB may be composed of 4 OFDM symbols as in [Method # 6]. In the drawing, #x represents the first OFDM symbol of slot #x.

[Method # 15] Constitution and arrangement of 7 symbol unit SSB based on 60 kHz SCS (FIG. 31)

■ Constructing SSB of NR L-band by expanding to 7 symbols and arranging it consecutively

Each extended SSB (seven consecutive OFDM symbols in FIG. 31) includes the existing four OFDM symbols SSB and a method of copying some OFDM symbols of the four OFDM symbols SSB to the remaining three OFDM symbols

- Four existing OFDM symbols SSB can be arranged in consecutive 4 OFDM symbols starting from 1st, 2nd, 3rd or 4th OFDM symbols of 7 OFDM symbols SSB

A part of the 4 OFDM symbols SSB copied to the added 3 OFDM symbols may be 3 OFDM symbols sequentially from the PSS or 3 OFDM symbols sequentially from the PBCH of the 2nd OFDM symbol

- 7 When the PSS OFDM symbol is repeated twice in the OFDM symbol SSB,

A portion of the PBCH may be copied to 8 RBs on each side of each PSS, or

· PBCH rate-matched based on RE with 8 RBs on each side of each PSS and can be assigned RE

When PSS is repeated, each PSS may be different from each other (e.g., different sequence mappings, or multiplying cover codes) to reduce the ambiguity of the starting position of an OFDM symbol within the SSB.

- If a part of the PBCH is repeated in the extended 7 OFDM symbol SSB,

The resource mapping of the additional transmitted PBCH for the purpose of ensuring the frequency diversity gain may be different from the PBCH of the existing 4 OFDM symbol SSB

· PBCH Apart from some iterations, DMRS can be generated based on 7 OFDM symbols without repeating

- This method can only be applied exclusively to cells operating in SA mode.

32 illustrates a downlink synchronization acquisition process according to an exemplary embodiment of the present invention. In the following method, the terminal may be replaced with a processor in the terminal or a communication modem in the processor.

Referring to FIG. 32, a terminal can receive a downlink signal on a carrier (S3202). In step S3204, the UE performs an SS-block detection process on the downlink signal, and acquires the downlink synchronization through the detection process in step S3206. Here, the SS-block may comprise a plurality of contiguous OFDM symbols based on a predetermined SCS. Also, based on the type of carrier, the predetermined SCS may belong to a first SCS set or a second SCS set, and the first SCS set and the second SCS set may not be the same.

Wherein the first SCS set is used when the carrier is a license band and the second SCS set is used when the carrier is a license-exempt band and the first SCS set includes 15 kHz, 30 kHz, 120 kHz, and 240 kHz And the second SCS set may include 60 kHz. Also, the first SCS set may not include 60 kHz. Also, when a plurality of SS-blocks are included in a 1 ms time unit and the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit, Block is a license-exempt band, the plurality of SS-blocks may continuously exist within the 1 ms time unit at the boundary of the 0.5 ms time point. In addition, the 1 ms time unit may include 14 OFDM symbols on a 15 kHz SCS basis, and each SS-block may include 4 consecutive OFDM symbols.

33 illustrates a downlink synchronization providing process according to an exemplary embodiment of the present invention. In the following method, the base station may be replaced with a processor in the base station, or a communication modem in the processor.

Referring to FIG. 33, a base station generates an SS-block (S3302) and transmits a downlink signal including the SS-block on a carrier (S3304). Here, the SS-block may comprise a plurality of contiguous OFDM symbols based on a predetermined SCS. Also, based on the type of carrier, the predetermined SCS may belong to a first SCS set or a second SCS set, and the first SCS set and the second SCS set may not be the same.

As described above, in the U-band, it is advantageous in terms of LBT that not only data SCS but also SSB SCS is used at 60 kHz. However, when SCS 60kHz for SSB is not defined, or considering the spectrum of U-band, the bandwidth occupied by SSB of 60kHz SCS is too large to be difficult to FDM with other channels (eg PDSCH, PDCCH, etc.) The SSB of the 60kHz SCS may not be defined or used. Thus, a SSB of 15 kHz or 30 kHz SCS can still be used. At this time, since the SSB arrangement defined in NR is discontinuous, there may be a disadvantage in LBT. There are two major ways to overcome or overcome these shortcomings.

First, as in [Method # 14], there is a method of constructing SSB such that a specific SSB composed of N OFDM symbols is not configured over a boundary of 0.5 msec.

[Method # 16] 30 kHz SCS-based SSB configuration and arrangement (Fig. 34)

■ In the same way as [Method # 14], there is a method of placing SSB at the boundary of 0.5 msec

○ When SSB is composed of 4 OFDM symbols as in [Method # 6], SSB index 0 can be consecutively arranged starting from 3rd OFDM symbol within 1 msec

○ When SSB is composed of 3 OFDM symbols as in [Method # 7], SSB index 0 can be consecutively arranged starting from 3rd OFDM symbol within 1 msec

[Method # 8] and [Method # 9] can be arranged consecutively starting from the first OFDM symbol within 1 msec of the first OFDM symbol of the SSB index 0

Alternatively, other signals and / or channels may be transmitted between the SSBs, permitting discrete SSB placement as in the 30kHz (1) or 30kHz (2) method of FIG. Here, since the SCS of the SSB need not necessarily be limited to 30 kHz, the following proposal also includes a 15 kHz SCS.

[Method # 17] Extension of discontinuous SSB (Figures 35-36)

■ How to extend the number of SSB symbols using PBCH of SSB (A)

The PBCH used for symbol extension may be designed to have a repetitive pattern in the time domain by repeating a specific symbol of the PBCH, or repeating the PBCH of a symbol not overlapping the SSS.

The PBCH used for symbol extension is not a structure in which some of the PBCHs of the SSB are simply repeated, but may be a rate-matched PBCH as the number of REs used for PBCH resource allocation is increased

○ DMRS of extended symbol can have additional value based on random sequence initialized in SSB instead of repeating DRMS included in SSB

A method of allocating SSB and QCL CSI-RS to expand the number of SSB symbols (B)

○ CSI-RS is configured to include minimum cell ID and SSB index information.

CSI-RSs used for this purpose in bursts (eg, DRS) transmitted for measurement and CSI-RSs used for this purpose in bursts used for data transmission may be configured differently

■ Symbols or REs placed in the bold box area in Figures 35-36 can be specified differently depending on SA or NSA

In case of SA, PBCH can be further transmitted in a bold box area as in method (A).

○ In case of NSA, CSI-RS can be further transmitted in the bold box area as in method (B).

35-36 show SSB extensions based on 15 kHz and 30 kHz SCS, respectively. Here, a bold box indicates QCL with adjacent SSB. In case of 15 kHz, the SSB can be extended like [Method # 17] by using the channel and / or signal of the adjacent SSB and QCL in the second OFDM symbol and the thirteenth OFDM symbol, respectively.

SSB extensions can be considered in the frequency domain as well as in the time domain. According to national regulations, in the U-band there may be a limit on the maximum transmit power per frequency bandwidth, so in order to utilize the maximum transmittable power efficiently, it is necessary to spread the signal as widely as possible in the frequency domain. Particularly, as shown in FIGS. 10 and 11, a method of extending the PSS OFDM symbols in the frequency domain where each OFDM symbol does not use the same number of RBs can be considered in the SSB. Since the number of RBs in the PSS symbol in the NR L-band system is smaller than the number of RBs in the remaining symbols in the SSB, a method for expanding the PSS is specifically proposed. If a new SSB structure is introduced in the U-band and the number of RBs in the other symbols is less, then the RB extension can be considered in the same way.

[Method # 18] The method of extending the RB of the PSS OFDM symbol in SSB (FIG. 37)

■ How to repeatedly allocate a specific RB in the frequency domain to PSS

○ How to generate sequence as PSS is transmitted in 20RB and extend RB in frequency domain

○ Existing 12 RB locations (12 RBs where the existing PSS is transmitted) are the same as the existing PSS, but additional RBs on both sides can be assigned new sequences.

■ Some RBs in the PBCH can be repeated and assigned to both sides of the PSS

Some RBs of rate-matched PBCHs can be allocated next to PSSs as the number of REs used for PBCH resource allocation has increased

5. SA와 NSA의 공존을 고려한 UE 동작5. UE operation considering coexistence of SA and NSA

Unlike LTE U-band LAA, U-band in NR is expected to support SA operation. In the case of a terminal supporting only the U-band, it may be difficult to expect a normal service even if a base station operating in the U-band operates as an NSA. Of course, the opposite can also be the case. In order to avoid such a case, the base station transmits information indicating that it is the base station that performs the SA service, the base station that performs the NSA service, or that only the terminal capable of the SA service is allowed to access or only the terminal capable of the NSA service is allowed to access May need to be broadcast. This can be broadcasted in the form of system information, or alternatively, in the U-band, some cell IDs may be reserved / assigned for the SA and the remaining cell IDs may be reserved / assigned for the NSA. Because the U-band basically occupies the medium through the LBT, fewer cell IDs may be needed in the L-band. In addition, information for distinguishing SA and NSA from the sequence generation information of the PBCH DMRS can be included.

Equation 1 illustrates the PBCH DMRS sequence.

Here, c (n) represents a scrambling sequence and is initialized using the following values at the beginning of each SSB.

- L _max = 4, n _hf is the number of the half-frame in which the PBCH is transmitted within the frame, i _SSB is the LSB (Least Significant Bit) 2 bits of the SSB index,

If L _max = 8 or 64, then n _hf is 0 and i _SSB represents the 3 LSB bits of the SSB index. The N ^cell _ID indicates a cell index.

In this method, when _Lmax = 4, i _SSB can be used as a parameter to distinguish between SA and NSA. Also, n _hf may be used as a parameter to distinguish SA from NSA depending on the period of SSB in the U-band.

Also, the UE can exclude a specific cell from a measurement object or a report object according to its operation mode (SA or NSA). For example, an SA (or NSA) terminal may exclude from a measurement cell target or omit from reporting if it is determined that a particular cell in an adjacent cell is an NSA (or SA).

Referring to FIG. 38, a wireless communication system includes a base station (BS) 110 and a terminal (UE) 120. If the wireless communication system includes a relay, the base station or the terminal may be replaced by a relay.

The base station 110 includes a processor 112, a memory 114, and a radio frequency (RF) unit 116. The processor 112 may be configured to implement the procedures and / or methods suggested by the present invention. The memory 114 is coupled to the processor 112 and stores various information related to the operation of the processor 112. [ The RF unit 116 is coupled to the processor 112 and transmits and / or receives wireless signals. The terminal 120 includes a processor 122, a memory 124 and a radio frequency unit 126. The processor 122 may be configured to implement the procedures and / or methods suggested by the present invention. The memory 124 is coupled to the processor 122 and stores various information related to the operation of the processor 122. [ The RF unit 126 is coupled to the processor 122 and transmits and / or receives radio signals.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

In the present document, the embodiments of the present invention have been mainly described with reference to a signal transmission / reception relationship between a terminal and a base station. This transmission / reception relationship is equally or similarly extended to the signal transmission / reception between the terminal and the relay or between the base station and the relay. The specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network including a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the terminal may be replaced by terms such as a UE (User Equipment), a Mobile Station (MS), and a Mobile Subscriber Station (MSS).

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

The present invention can be used in a terminal, a base station, or other equipment of a wireless mobile communication system.

Claims

A method for a terminal to acquire downlink synchronization in a wireless communication system,

Receiving a downlink signal on a carrier;

Performing a detection of a synchronization signal (SS) block on the downlink signal, the SS-block including a plurality of consecutive Orthogonal Frequency Division Multiplexing (OFDM) symbols based on a predetermined subcarrier spacing (SCS); And

And acquiring the downlink synchronization through the detection process,

Wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of carrier, and wherein the first SCS set and the second SCS set are not the same.
The method according to claim 1,

The first SCS set is used when the carrier is a license band and the second SCS set is used when the carrier is a license-exempt band,

The first SCS set comprises 15 kHz, 30 kHz, 120 kHz and 240 kHz, and the second SCS set comprises 60 kHz.
3. The method of claim 2,

Wherein the first SCS set does not include 60 kHz.
The method of claim 3,

A plurality of SS-blocks are included in the 1 ms time unit,

If the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit,

Wherein when the carrier is a license-exempt band, the plurality of SS-blocks are consecutively present at the 0.5 ms time point within the 1 ms time unit.
5. The method of claim 4,

Wherein the 1 ms time unit comprises 14 OFDM symbols on a 15 kHz SCS basis and each SS-block comprises 4 consecutive OFDM symbols.
A terminal used in a wireless communication system,

An RF (Radio Frequency) module; And

The processor comprising:

Receiving a downlink signal on a carrier,

(SS) block for the downlink signal, wherein the SS-block includes a plurality of consecutive OFDM symbols based on a predetermined subcarrier spacing (SCS), and

Through the detection process, to obtain the downlink synchronization,

Wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of the carrier, and wherein the first SCS set and the second SCS set are not the same.
The method according to claim 6,

The first SCS set is used when the carrier is a license band and the second SCS set is used when the carrier is a license-exempt band,

The first SCS set comprises 15 kHz, 30 kHz, 120 kHz and 240 kHz, and the second SCS set comprises 60 kHz.
8. The method of claim 7,

Wherein the first SCS set does not include 60 kHz.
9. The method of claim 8,

A plurality of SS-blocks are included in the 1 ms time unit,

If the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit,

Wherein the plurality of SS-blocks are consecutively present at the 0.5 ms time point within the 1 ms time unit when the carrier is a license-exempt band.
10. The method of claim 9,

Wherein the 1ms time unit comprises 14 OFDM symbols on a 15kHz SCS basis, each SS-block comprising 4 consecutive OFDM symbols.
A method for a base station to provide downlink synchronization in a wireless communication system,

Generating a synchronization signal (SS) block, the SS-block including a plurality of consecutive Orthogonal Frequency Division Multiplexing (OFDM) symbols based on a predetermined subcarrier spacing (SCS); And

And transmitting a downlink signal including the SS-block on a carrier,

Wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of carrier, and wherein the first SCS set and the second SCS set are not the same.
12. The method of claim 11,

The first SCS set is used when the carrier is a license band and the second SCS set is used when the carrier is a license-exempt band,

The first SCS set comprises 15 kHz, 30 kHz, 120 kHz and 240 kHz, and the second SCS set comprises 60 kHz.
13. The method of claim 12,

Wherein the first SCS set does not include 60 kHz.
14. The method of claim 13,

A plurality of SS-blocks are included in the 1 ms time unit,

If the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit,

Wherein when the carrier is a license-exempt band, the plurality of SS-blocks are consecutively present at the 0.5 ms time point within the 1 ms time unit.
15. The method of claim 14,

Wherein the 1 ms time unit comprises 14 OFDM symbols on a 15 kHz SCS basis and each SS-block comprises 4 consecutive OFDM symbols.
A base station used in a wireless communication system,

An RF (Radio Frequency) module; And

The processor comprising:

Block, wherein the SS-block includes a plurality of contiguous Orthogonal Frequency Division Multiplexing (OFDM) symbols based on a predetermined subcarrier spacing (SCS)

Block, the SS-block being configured to transmit a downlink signal including the SS-

Wherein the predetermined SCS belongs to a first SCS set or a second SCS set based on the type of the carrier and wherein the first SCS set and the second SCS set are not the same.
17. The method of claim 16,

The first SCS set is used when the carrier is a license band and the second SCS set is used when the carrier is a license-exempt band,

The first SCS set includes 15 kHz, 30 kHz, 120 kHz, and 240 kHz, and the second SCS set includes 60 kHz.
18. The method of claim 17,

The first SCS set does not include 60 kHz.
19. The method of claim 18,

A plurality of SS-blocks are included in the 1 ms time unit,

If the carrier is a license band, the plurality of SS-blocks are discontinuous with a 0.5 ms time point within the 1 ms time unit,

Wherein when the carrier is a license-exempt band, the plurality of SS-blocks are consecutively present at the 0.5 ms time point within the 1 ms time unit.
20. The method of claim 19,

Wherein the 1ms time unit comprises 14 OFDM symbols on a 15kHz SCS basis, each SS-block comprising 4 consecutive OFDM symbols.