KR20170020699A - Apparatus for transmitting and receiving data through unlicensed band - Google Patents

Abstract

The processor includes a processor, a memory, and a wireless communication unit. The processor executes a program stored in the memory to generate a sub-frame synchronizing signal in at least one remaining sub-frame except for sub-frame 0 or sub-frame 5 among a plurality of sub- Receiving a signal, and performing a step of detecting a sub-frame synchronization signal using the sub-frame number of sub-frame 0 or sub-frame 5, is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus and a transmitting apparatus for transmitting and receiving data through a license-

The present disclosure relates to a transceiver for transmitting and receiving data through a license-exempt band.

As the number of mobile Internet users increases through mobile communication systems, mobile communication providers are seeking an efficient way to increase the capacity of a mobile communication system. The most efficient and intuitive way is to increase the bandwidth by securing additional license band frequencies for mobile communication systems. However, while the licensed band frequency has the advantage of being able to provide efficient mobile communication services through the exclusive use of the frequency, the licensing and usage cost of the frequency is high, and the license band frequency allocated for the mobile communication system is limited . Accordingly, mobile telecommunication carriers and manufacturers will be able to use frequency licenses (licenses / license-exempt bands, etc.) that are relatively freely available and inexpensive, such as license-exempt band frequencies, TV white space, ) Are under study to provide mobile communication services.

The communication system installed at the license-exempt band frequency has the following limitations.

First, the transmit power is limited to minimize the impact on other systems sharing the license-exempt band frequency. Thus, if a licensed band system and a license-exempted band system are installed in the same place, a coverage hole may occur.

In addition, for fair coexistence with adjacent license-exempt band systems, the license-exempt band frequencies shall be used discontinuously or opportunistically. Accordingly, the transmission reliability of the control channel and the common channel of the mobile communication system can be lowered.

In addition, the frequency regulation of the license-exempt band shall be complied with. Systems using license-exempt band frequencies should operate based on Listen Before Talk (LBT) for data transmission. For example, a device (or system) that uses a license-exempt band frequency should perform a clear channel assessment (CCA) and determine whether to use the channel according to the CCA results. In this case, according to the result of CCA, even if occupying a channel, the channel occupation time may be limited according to the frequency regulation, the channel can not be occupied for a time exceeding the maximum channel occupation time, and a CCA is additionally performed do.

Due to the limitations of the above-mentioned license-exempt band system, a scenario for installing / operating the licensed band system and the license-exempted band system in complementary form is being examined rather than a standalone system using only the license-exempt band in providing mobile communication services . In such a scenario, reliable control functions such as terminal control and mobility management are performed over the licensed band frequency, and traffic functions such as wireless transmission rate increase and wireless traffic load balancing supplement the licensed band system using the license-exempt band system . For example, a control function and a traffic function are performed through a carrier in a license band, and a traffic function is performed through a carrier in an unlicensed band.

The above operation of the license band carrier and the license-exempt band carrier can be implemented through the Carrier Aggregation (CA) technology of 3GPP LTE. For example, a time division duplex (TDD) carrier, which is a carrier aggregation scheme between a license-deed frequency division duplex (FDD) carrier and a licensed band carrier, or a license- And a carrier aggregation scheme between the license band carriers.

A cellular system using a license-exempt band can provide a mobile communication service with guaranteed quality of service by utilizing low-cost, rich frequency resources and advanced interference control technology. However, new coexistence techniques and interference control techniques are needed to solve the coexistence problems with various regulations and other license-exempt band systems in the license-exempt band and to secure the above advantages. In particular, due to the nature of the license-exempt band, devices operating in the license-exempt band can occupy and use the channel. In this case, if carrier aggregation is applied in order to solve problems with coexistence with other devices in the license-exempt band and restrictions on the operation in the license-exempt band, the characteristics of the licensed band and the license-exempted band must be considered simultaneously. In addition, it should be possible to provide a reliable service based on the existing cellular system reflecting the restriction (characteristic) for device operation in the license-exempted band.

One embodiment provides an apparatus for receiving an auxiliary synchronization signal via a license-exempt band.

Another embodiment provides an apparatus for transmitting data or traffic over a license-exempt band.

According to one embodiment, a receiving apparatus for receiving a signal via a license-exempt band is provided. The receiving apparatus includes a processor, a memory, and a wireless communication unit, and the processor executes a program stored in the memory to store at least one remaining sub-frame excluding the sub-frame 0 or the sub-frame 5 among the plurality of sub- And a step of detecting an auxiliary sync signal using the subframe number of the subframe 0 or the subframe 5.

The auxiliary synchronizing signal in the receiving apparatus is composed of a sequence of length 62 generated using the following equation,

[Mathematical Expression]

The DMTC may include subframes 0, 1, 2, 3, 4 or subframes 5, 6, 7, 8,

The processor of the receiving apparatus may further execute a program stored in a memory to acquire a cell ID based on the detection result of the auxiliary synchronous signal.

The processor in the receiving apparatus performs a step of receiving an auxiliary synchronizing signal, and the processor performs a step of receiving an auxiliary synchronizing signal in a first sub-frame of at least one remaining sub-frame, and the processor executes a program stored in the memory , And receiving data in the next sub-frame of the first sub-frame among the remaining sub-frames.

The processor of the receiving apparatus may perform the step of receiving the auxiliary synchronous signal, the main synchronous signal and the cell specific reference signal in the first sub-frame of the remaining sub-frames when performing the step of receiving the auxiliary synchronous signal.

In the receiving apparatus, the processor may further perform the step of receiving the channel state information-reference signal when performing the step of receiving the auxiliary synchronizing signal, the main synchronizing signal, and the cell specific reference signal.

In the receiver, the auxiliary synchronization signal, the main synchronization signal, and the cell specific reference signal may be received within 12 OFDM symbols included in the first subframe.

The processor at the receiving apparatus may further execute a program stored in the memory to detect the cell specific reference signal using the slot number of the slot included in the first subframe.

According to another embodiment, a transmitting apparatus for transmitting data via a license-exempt band is provided. The transmitter includes a processor, a memory, and a wireless communication unit. The processor executes a program stored in a memory to receive a HARQ ACK / NACK corresponding to the PDSCH. The HARQ ACK / NACK includes a number of HARQ NACKs Increasing the contention window value of the contention window to access the channel, and performing the channel access procedure based on the increased contention window value.

The processor executes a program stored in the memory to reduce a contention window value if the number of HARQ ACKs is greater than the number of HARQ NACKs by a predetermined ratio, May be performed.

The processor of the transmitting apparatus may perform the CCA or the extended CCA based on the increased contention window value when performing the channel access procedure based on the increased contention window value.

When performing a step of receiving HARQ ACK / NACK, the processor in the transmitting apparatus may perform a step of receiving a HARQ ACK / NACK corresponding to a PDSCH of a first subframe included in the COT for a channel.

The processor at the transmitting device may further execute a program stored in the memory to instruct the receiving device to update the value of the increased contention window or the contention window value.

According to another embodiment, a transmitting apparatus for transmitting traffic through a license-exempt band is provided. The transmitting apparatus includes a processor, a memory, and a wireless communication unit, and the processor executes a program stored in the memory to transmit traffic corresponding to a second priority class lower than a first priority class used for channel access And transmitting the traffic corresponding to the third priority class higher than the first priority class after all the traffic corresponding to the second priority class is transmitted.

The energy detection thresholds corresponding to the first priority class, the second priority class, and the third priority class may be different from each other in the transmitting apparatus.

The traffic corresponding to the second priority class in the transmitting apparatus may be a discovery reference signal or a discovery signal, and the traffic corresponding to the third priority class may be a PDSCH.

In the transmitting apparatus, the first priority class, the second priority class, and the third priority class may be determined according to the type of traffic.

In the transmitting apparatus, the processor executes the program stored in the memory to perform channel access based on the CCA parameters determined according to the first priority class, the second priority class, and the third priority class .

In the transmitting apparatus, a different channel occupation time is set in each of the second priority class and the third priority class, the processor executes a program stored in the memory, and when transmitting the traffic corresponding to the second priority class, And may transmit the traffic during the channel occupancy time corresponding to the second priority class.

In performing the extended CCA for efficiently using the license-exempt band, the contention window can be efficiently updated based on the HARQ ACK / NACK and the like.

1A, 1B, 2A, and 2B are conceptual diagrams illustrating a method of allocating uplink resources of a license-exempted band through a license band.
FIG. 3 is a flowchart illustrating a channel access method of a license-exempt band according to an embodiment.
4A to 4C are layout diagrams showing a mobile communication system in which a UCC is set and operated.
FIG. 5 is a conceptual diagram illustrating a CCA by a contention window adjustment according to an embodiment.
6 is a conceptual diagram illustrating a channel access method based on a priority according to an embodiment.
FIG. 7 is a conceptual diagram illustrating a data transmission method according to the CCA end according to an embodiment.
8 is a conceptual diagram illustrating a channel access method of a multi-carrier network according to an embodiment.
9 is a conceptual diagram illustrating a channel access method of a multi-carrier network according to another embodiment.
10 to 12 are conceptual diagrams illustrating a channel access method of a multi-carrier network according to another embodiment.
13 is a conceptual diagram illustrating a multi-cell network according to an embodiment.
14 to 16 are conceptual diagrams illustrating a channel access method in a multi-cell network according to an embodiment.
17 is a conceptual diagram illustrating a channel access method when DRX is performed according to an embodiment.
18 is a conceptual diagram illustrating a channel access method when DRX is performed according to another embodiment.
19 is a block diagram illustrating a wireless communication system according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present disclosure can be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention in the drawings, parts not related to the description are omitted, and like reference numerals are given to similar parts throughout the specification.

Throughout the specification, a terminal is referred to as a mobile station (MS), a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE), a machine type communication device MTC device and the like and may include all or some functions of MT, MS, AMS, HR-MS, SS, PSS, AT, UE,

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station (HR) (BS), a home Node B (HNB), a home eNodeB (HeNB), a pico BS, a macro BS, a micro BS ), Etc., and all or all of ABS, Node B, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR- And may include negative functionality.

The method of adjusting the contention window and applying the backoff according to the present invention is a method in which a transmitting apparatus performing a CCA accesses a channel for data transmission or a receiving apparatus accesses a channel for data reception And can be applied to all devices that perform CCAs. For example, the CCA performed by the base station for data transmission (uplink data transmission) of the terminal, the CCA performed by the base station to transmit data (downlink data transmission) to the terminal, Or a CCA performed by a terminal to transmit data to a base station using resources allocated by the base station, and the like.

1A, 1B, 2A, and 2B are conceptual diagrams illustrating a method of allocating uplink resources of a license-exempted band through a license band.

The frame based equipment (FBE) and the load based equipment (LBE) of FIGS. 1A, 1B, 2A and 2B are channel access methods defined in the ETSI standard and the 3GPP standard, The method specified in the standard shall apply mutatis mutandis. The channel occupancy time is assumed to be 4 ms when the channel is accessed.

1A and 1B, a BS allocates resources to a UE through cross-carrier scheduling (uplink grant (UL grant)). After that, the UE transmits data to the BS The UEs UE1 and UE3 can transmit data by occupying the channel and the other UEs UE2 and UE4 can not determine that the CCA result channel is occupied by another device and can not transmit data. , The time when the UE transmits data to the BS is the time when 4 subframes have passed since the transmission of the reference UL grant when the primary cell (PCell) is the FDD, and when the PCell is the TDD, 4 to 7 subframes have elapsed according to link / downlink (UL / DL) configuration.

Referring to FIGS. 2A and 2B, a base station allocates resources to a mobile station through self-scheduling. At this time, the UEs (UE2 and UE4) performing the CCA while the specific UEs (UE1 and UE3) transmit data judge that the channel is occupied by another device and can not transmit data.

FIG. 3 is a flowchart illustrating a channel access method of a license-exempt band according to an embodiment.

The channel access method of the license-exempted band shown in FIG. 3 is a method for allowing terminals such as UE2 and UE4 in FIGS. 1 and 2 to occupy channels after the CCA.

Referring to FIG. 3, a communication device such as a base station or a terminal that transmits data through a channel of a license-exempt band can perform an initial CCA and an extended CCA to occupy a channel of a license-exempt band.

First, the communication apparatus determines whether a data transmission request has occurred (S301), and maintains an idle state when there is no data transmission request (S302). When a data transmission request is generated, an initial CCA is performed (S303). If the initial CCA period (BiCCA) (for example, 34us) is Idle during the initial CCA, the data is transmitted (S304). Thereafter, the communication apparatus determines whether additional data transmission has occurred (S305), and returns to the idle state if there is no further data to be transmitted.

However, if there is additional data to be transmitted, or if the channel is busy or occupied during the initial CCA (hereinafter referred to as "BUSY"), the communication device performs the extended CCA. In order to perform the extended CCA, the communication device generates a random counter N from the contending window q (i.e., [0, q-1]) (S306). At this time, the contention window q may be updated through dynamic back-off or semi-static backoff between X and Y (S307). And HARQ ACK / NACK may be used when updating the contention window.

Thereafter, the communication apparatus determines whether the channel is Idle during the extended CCA delay period (DeCCA) (S308). If the channel is Idle, the communication apparatus determines whether the random counter N is 0 (S309). If the random counter N is 0, the data is transmitted (S304). However, if the random counter N is not 0, the communication device senses the channel for one eCCA slot period (e.g., 9us or 10us) (S310). Thereafter, if it is determined that the channel is not busy (S311), the communication apparatus decreases the random counter N by 1, and if it is determined that the channel is busy (S312), the communication apparatus returns to step S308.

In Figure 3, the Defer Period (DP) is an additional sensing period that includes at least one CCA slot. Also, depending on whether or not the previously transmitted data has been successfully transmitted, the contention window q can be adjusted in the channel access / occupation process, and a backoff can be applied dynamically or semi-statically. However, due to the problem that the data success or failure is displayed unclear (e.g., ACK / NACK received from a plurality of devices, ACK / NACK received after several subframes (i.e., several ms) Dynamic (quasi-static) backoff is difficult to apply.

4A to 4C are layout diagrams showing a mobile communication system in which a UCC is set and operated.

Referring to FIG. 4A, an indoor and an outdoor low power cell in which an LCC and a UCC are operated in one cell are shown. In each case, the PCell may be a macro cell, and the secondary cell may be co-located or non-co-located with the PCell.

Referring to FIG. 4B, the PCell in which the LCC is operated and the (low power) SCell in which the LCC and the UCC are operated are shown. Each SCell operating LCC and UCC can be deployed indoors and outdoors. The PCell may be a macro cell or a small cell, and the SCell in which the LCC is operated and the SCell in which the UCC is operated may be co-located with each other or non-co-located.

Referring to FIG. 4C, a PCell in which the LCC is operated and a (low power) SCell in which the UCC is operated are shown. The SCell in which the UCC is operated can be placed indoors or outdoors, and the PCell in which the LCC is operated can be a macrocell or a small cell.

FIG. 5 is a conceptual diagram illustrating a CCA by a contention window adjustment according to an embodiment.

In FIG. 5, the BS performs CCA to transmit data through the UCC, and the MS transmits HARQ ACK / NACK for data received from the BS to the BS through the P-LCC. Referring to FIG. 5, the UE transmits a NACK to the base station (subframe n + 2 and subframe n + 3) with respect to data transmitted in subframe n-2 and subframe n-1, In the sub-frame n + 6 and the sub-frame n + 7. Thereafter, the UE informs NACK of retransmitted data, and the base station retransmits the retransmitted data in subframes n + 14 and n + 18. At this time, the base station can perform the extended CCA by selecting the CCA performing slot (N) before performing the CCA. When the channel is occupied by the CCA, the channel occupancy time (COT) is assumed to be 4 ms.

In order to transmit data in sub-frame n-4, the base station performs initial CCA (or extended CCA) in sub-frame n-5, occupies the channel, and transmits an initial signal (IS) do. At this time, N selected when the extended CCA is performed after the initial CCA can be arbitrarily selected from among the competing windows (0 to q-1). If the data transmission after the initial CCA is not successful (for example, HARQ NACK is received), the base station updates q in the previous subframe (subframe n + 5) of the subframe for data retransmission, The extended CCA is performed using the selected N among q-1. If it is determined that there is more data to be transmitted at the time when the maximum COT expires (e.g., subframe n + 10), the base station may newly perform the CCA for data transmission, in which case the initial CCA may be omitted have. If the initial CCA is omitted, the transmitting device reuses the previous competing window (0 to q-1) applied at the previous CCA to select N. In the COT interval, initial data transmission, data retransmission corresponding to HARQ NACK, and new data transmission corresponding to HARQ ACK are included. The contention window can be updated according to Equation (1) below.

In Equation (1), q is a competition window for N that selects an extended CCA interval (CCA slot) according to frequency regulation when operating a license-exempt band, and represents the maximum value of N values. k is an arbitrary value (k? 0), X is the minimum value of the contention window, and Y is the maximum value of the contention window. Y is greater than or equal to X (Y? X).

q can be changed according to COT. For example, q may be determined to satisfy Equation 2 below.

In Equation (2), COT is in units of ms. Or q may be determined as any value independent of the COT, or may be determined as one of the predetermined values (e.g., 4, 8, or 16) and may be determined as a value between X and Y.

If k is greater than 1 (k> 1), the contention window is updated to a value greater than the previous contention window. If k is less than 1 (k < 1), the contention window is updated to a smaller value than the previous contention window. If k is 0 (k = 0), the contention window is updated to the minimum value (i.e., k = X) or initialized. If k is 1 (k = 1), the contention window is not updated and the previous contention window value is reused.

X can be determined according to Equation (3) below.

Or X may be the smallest natural number or arbitrary value of natural numbers greater than the minimum value (4 or 16, etc.) defined in the frequency regulation of the license-exempt band. Or X may be any number greater than the minimum defined in the frequency regulation of the license-exempt band.

Y may be the largest natural number or arbitrary value of natural numbers less than the maximum value (such as 32 or 1024) defined in the frequency regulation of the license-exempt band.

On the other hand, when X and Y are the same (X = Y), k is 1 (k = 1) and the following equation (4) is established.

The updating of the contention window may be performed according to one of the following methods or a combination of two or more. In the updating method of the contention window, k may be determined to be an arbitrary value. Updating of the contending window may include maintaining, increasing, decreasing, resetting to the initial value, etc. of the previous contending window value. In the following, m denotes the number of HARQ ACKs, and n denotes the number of HARQ NACKs. The number of HARQ ACKs / NACKs m and n is the number of HARQ ACK / NACKs received before the CCA is performed after a specific time.

- A method of maintaining previous q regardless of HARQ ACK / NACK.

- How to update q in the next CCA regardless of HARQ ACK / NACK.

- How to update q when HARQ NACK is received.

A method for updating q when HARQ ACK / NACK for data transmission is HARQ NACK;

- When there are m and n HARQ ACK / NACK for data transmission, respectively, the transmitting apparatus can determine the update of q by comparing m and n. If k = 1, the previous q is maintained. If k > 1, q is increased. If 0 < k < 1, q is decreased. If k = 0, q can be reset to the initial value.

- when n = 0 (all HARQ ACK / NACK received are HARQ ACK), and q is updated when m is greater than or equal to a predetermined value.

- when m = 1 (all HARQ ACK / NACKs received are HARQ NACK), and q is updated when n is greater than or equal to a predetermined value.

a method of updating q when m > n (where HARQ ACK is greater than HARQ NACK), when the difference between m and n is greater than or equal to a predetermined value, or when the ratio of m and n is greater than or equal to a predetermined value , Since the HARQ ACK is larger than the HARQ NACK, q is reduced).

a method of updating q when m < n (when HARQ NACK is greater than HARQ ACK), when the difference between m and n is greater than or equal to a predetermined value, or when the ratio of m and n is greater than or equal to a predetermined value , Since HARQ NACK is greater than HARQ ACK, q is increased).

- When m = n (when the number of HARQ ACK and HARQ NACK is the same), a method of updating q

A method of updating q when the ratio of HARQ ACK / NACK is greater than or equal to a predetermined value, such as m / n, n / m, n / (m + n), m /

- a method for updating q when the number of m is greater than or equal to a predetermined value.

- a method for updating q when the number of n is greater than or equal to a predetermined value.

- a method of updating q when the number of m and n is greater than or equal to a predetermined value, respectively.

A method for updating q when HARQ NACK for data with the lowest level MCS is received.

At this time, if the HARQ ACK is received after the data with the lowest level MCS applied, the contention window value q can be maintained or reduced (or reset to the initial value), and the q value can be increased when HARQ NACK is received. At this time, it is possible to determine whether to update q according to the number of received HARQ ACKs, the number of HARQ NACKs, or the ratio of HARQ ACK / NACKs.

- A method of updating q according to HARQ ACK / NACK for data transmitted in a particular subframe located within the COT (e.g., the first part of the occupied channel or some last subframe, etc.).

- update q when at least one HARQ NACK is received, and perform only retransmission of data in the re-occupied channel.

In this case, when HARQ ACK / NACK is reported mixed from one receiving apparatus, the HARQ ACK / NACK reported from the receiving apparatus may not be used to determine whether to update the contention window. And, the HARQ ACK / NACK received after the update of q may not be used to determine whether to update the contention window. The HARQ ACK / NACK reported prior to a certain time may not be used to determine whether to update the contention window.

When the UE attempts to transmit data to the Node B through the uplink resource, the Node B instructs the UE to update the updated q or q in resource allocation for data retransmission, and the UE transmits the received q or q And a k-value for updating the CCA. Or a contention window update for data retransmission of the MS based on the q or k value preset between the MS and the BS. Alternatively, the UE may determine to update the contention window according to whether the MCS previously applied is changed or not. For example, if the MCS is changed from a higher level MCS to a lower level MCS, or if the MCS is changed from a lower level MCS to a higher level MCS, the terminal can update the contention window. When two or more uplink resources are allocated to the UE (for example, one uplink resource is dedicated to data retransmission and the remaining uplink resources are dedicated to initial transmission of data) The update can be separately determined. If there is a time longer than a predetermined time before the UE performs the uplink data transmission after the CCA (for example, before the subframe k after the uplink grant (UL grant)), It may not perform an action (e.g., a contention window update).

On the other hand, the contention window can be updated according to Equation (5) below.

If (5) is applied, q may be updated (increased or decreased or maintained) to a value changed by k in the previous q. Or q may be updated based on the channel access / occupancy or data transmission result without being based on the HARQ ACK / NACK.

Hereinafter, a method of updating a contention window according to a channel state will be described in detail. In the CCA performed for channel access / occupancy, the q value of the contention window can be updated according to the measured channel state. For example, the parameter representing the channel state may be compared with a predetermined value, and the update of the contention window may be determined based on the comparison result. Or the number of times the channel has occupied the channel since the CCA, or the number of times the channel has not been occupied, the update of the contention window can be determined.

(Or EPDCCH) when the resource allocation scheme of the base station is self-scheduling (or self-carrier scheduling) , The resource allocation information for data transmission is included in the same carrier as the data transmission. At this time, there may occur a case where there is no HARQ ACK / NACK for the (E) PDCCH, and the UE can receive data only when the (E) PDCCH is successfully received. Therefore, Is difficult to update. That is, when the PDCCH is not successfully received, the UE may not be able to receive data. Therefore, when the UE updates the contention window, the UE ignores the HARQ ACK / NACK transmission result (i.e., ACK or NACK), or can be recognized as a NACK at all times. Upon receiving the feedback on the data from the receiving apparatus in the self-scheduling, the transmitting apparatus determines that the data is not correctly transmitted due to the bad channel state, applies the lower-level MCS (more robust MCS) , Or can perform the CCA by resetting to the initial contention window.

If the base station's resource allocation scheme is cross-carrier scheduling, the base station can update the contention window based on the HARQ ACK / NACK received as feedback from the receiving apparatus.

Meanwhile, the base station can add a resource allocation for retransmission to the HARQ ACK / NACK. The information on the updated contention window may be included in resource allocation for data transmission or may be included in resource allocation for data retransmission. The base station can then perform the CCA for retransmission based on the updated contention window. On the other hand, if the base station does not allocate resources for retransmission or allocates resources for retransmission, the base station can not update the contention window or reset the contention window to an initial value. Alternatively, when the BS allocates resources, the UE informs the N selected in the contention window and performs the CCA during the N CCA slots, so that the UE can perform the CCA during the N CCA slots.

Hereinafter, a channel access method according to priority of transmitted traffic will be described in detail. Priority can be set in the traffic transmitted in the license-exempt band channel according to the characteristic or kind of the traffic, and channel access can be performed according to the set priority. For example, FBE and LBE option A / B in ETSI or LBT categories 2, 3, 4 in 3GPP. In the present description, priority can be set as follows according to the characteristics or types of traffic.

- Priority based on traffic type, such as video, audio, and general traffic

- Priority according to whether it is a control channel or a data channel

- Priority according to specific channel types such as PDCCH, PDSCH, PUSCH, PUCCH

- Priority according to purpose of transmitted data such as DRS, PDSCH

CCA parameters and channel access methods can be independently applied according to each priority.

A priority class (LBT priority class) is set, and a CCA parameter is determined for each set class, so that channel access can be performed. Table 1 shows the CCA parameters for prioritized channel access.

LBT priority class CW _min (X) CW _max (Y) n One 3 7 One 2 7 15 One 3 15 63 3 4 15 1023 7

Referring to Table 1, CW _min and CW _max are the minimum contention window size and maximum contention window size, respectively, and n is the number of CCA slots included in the defer period (DP). For example, since CW _min , CW _max , and n are smaller than those of other classes (class 2, 3, or 4), class 1 is likely to succeed in channel access. Other parameters for the CCA not shown in Table 1 (e.g., Energy Detection Threshold, etc.) may also be set differently for each class. The CCA parameters according to the priority class can be applied to the above-described CCA slot determination, re-determination, adjustment and the like, and can be applied to other CCA methods not described in this specification. When traffic corresponding to a plurality of classes is transmitted, a CCA parameter applied to each class can be used. However, when traffic corresponding to a plurality of classes is transmitted, a CCA parameter application method may be additionally required.

Hereinafter, a case where traffic included in two or more classes is serviced based on the priority order will be described with reference to FIG. 6, J and K represent LBT priority class level (QCL) parameters. If K is greater than J (K> J), then both the initial CCA and the extended CCA are performed, and if K is less than J or equal to J (K ≦ J), only the extended CCA may be performed without the initial CCA .

In the present description, the determination / use of parameters (e.g., CCA parameters, channel occupancy time, etc.) for data transmission through channel occupancy / use may be determined by the transmitting apparatus (e.g., base station or terminal) &Lt; / RTI &gt; Alternatively, the base station may determine a parameter for channel occupancy or use for uplink traffic transmission of the UE, and may transmit the parameter according to the type (or class) of the allocated traffic when allocating the uplink resource.

After receiving the parameter for channel occupancy or use from the base station, the terminal can perform CCA and data transmission using the received parameters. If the base station does not indicate some or all of the parameters for channel occupancy or use, or if the terminal does not indicate some or all of the parameters, then the method described below applies, It can only be applied to all parameters. The transmitting apparatus can transmit the traffic through the occupied channel after performing the CCA using the parameters related to the channel occupancy corresponding to the traffic class. At this time, only the traffic having the same class as the class of the parameter used at the time of performing the CCA is transmitted, or the traffic having the same class as the class of the parameter used at the time of executing the CCA is transmitted during the occupied channel time .

Referring to FIG. 6A, only traffic of the same class is transmitted in a channel occupied after the CCA. At this time, the channel occupation time of each class may be set differently, and the data may be transmitted only during the channel occupancy time corresponding to the class. When transmitting the data, the transmitting device carries out the CCA to occupy the channel and transmit the data through the occupied channel. If there is no traffic of the same class as the class of parameters used for CCA performance within the allowed channel occupancy time, the transmitting device either does not use the occupied channel, or transmits data regardless of the traffic class during the remaining channel occupancy time .

Referring to FIG. 6 (b), a traffic transmitting apparatus (for example, a base station or a terminal) accesses / occupies a channel using a CCA corresponding to a relatively low priority class, Through different classes of different traffic. Referring to FIG. 6C, the transmitting apparatus accesses / occupies a channel using a CCA corresponding to a class of a relatively higher priority, and then transmits different classes of traffic through the occupied channel do.

For example, when a transmitting apparatus transmits different traffic having priority classes 1 and 3, the transmitting apparatus accesses the channel using the CCA corresponding to the priority class 1, occupies the channel by the COT corresponding to the class 1 The traffic corresponding to the priority classes 1 and 3 can be transmitted through the occupied channel (Fig. 6 (c)). Or when the transmitting apparatus transmits different traffic of priority classes 1 and 3, the transmitting apparatus accesses the channel using the CCA corresponding to the priority class 3, occupies the channel by the COT corresponding to the class 3, It is possible to transmit the traffic corresponding to the priority classes 1 and 3 through the occupied channel (Fig. 6 (b)).

At this time, when data is transmitted over at least one TTI, the class of data transmitted in a predetermined TTI (for example, the initial TTI, the front partial TTI, the last partial TTI, all the TTI, or some TTI) All may be set to 1 or the number or ratio of classes of data transmitted in a predetermined TTI may be predetermined. That is, in the COT of the occupied channel, the transmitting apparatus preferentially transmits data corresponding to the priority class applied for channel occupancy. Thereafter, if there is no data corresponding to the priority class applied for channel occupancy (all data corresponding to the corresponding priority class is transmitted), traffic corresponding to another priority class in the same TTI or later TTI in the allowed COT Can be transmitted.

If a re-determination or adjustment (e.g., HARQ ACK / NACK based update) of the previous CCA slot is required, the CCA parameters for the CCA parameters corresponding to other priorities as well as the CCA parameters for the most recent CCAs Recall or adjustment of the latest CCA slot can also be applied to slot recrystallization or adjustment. Or channel access may be attempted using the CCA parameter such that only traffic having the same priority as the priority of previously transmitted traffic is transmitted. In this case, traffic having the same priority over the occupied channel may be transmitted, or traffic having the same priority may be transmitted in some TTI of the occupied channel. Alternatively, traffic having the same priority only in the initial TTI may be transmitted, or each TTI may include traffic having at least one same priority. That is, traffic corresponding to the same priority is preferentially transmitted, and traffic corresponding to another priority is transmitted in the same TTI or later TTI within the allowed COT (when there is no data corresponding to the corresponding priority class) .

In order for different traffic having different priorities to be serviced (or exchanged) simultaneously in the occupied channel through the new channel occupation attempt, the transmitting apparatus uses the parameters of the class having the highest priority or the class having the lowest priority CCA can be performed.

When the transmitting apparatus performs the CCA using the parameter corresponding to the class having the highest priority, the predetermined number of TTIs (the first TTI in the COT, the first TTI, or all the TTIs) , The highest class of data can be serviced. That is, the higher class data in the allowed COT is preferentially serviced (if there is no more data corresponding to the corresponding priority class), and the lower class data can be sequentially served in the same TTI or later TTI. In this case, when the transmitting apparatus performs the CCA using the parameter corresponding to the class having the highest priority, the transmitting apparatus performs the initial CCA and the extended CCA, and the transmitting apparatus performs the CCA using the parameter corresponding to the remaining class In doing so, the transmitting apparatus can perform only the extended CCA.

When a transmitting apparatus performs a CCA using a parameter corresponding to a class having a relatively low priority, the transmitting apparatus occupies a channel determined to be Idle, so that the priority is relatively prioritized in the COT corresponding to the class You can send traffic without. Also, when the transmitting apparatus determines that the CCA is performing a CCA using a parameter corresponding to a class having a relatively low priority and the CCA slot is freeze, the transmitting apparatus has the highest priority CCA can be performed by applying the parameter corresponding to the class. Thereafter, when the transmitting apparatus occupies the channel again, the transmitting apparatus 1) reuses the freezed CCA slot, or 2) performs only the extended CCA (at this time, the CCA slot is determined again) The initial CCA and the extended CCA can be performed using the corresponding parameters (at this time, the CCA slot and the like can be determined again).

On the other hand, the channel access method can be changed according to the purpose of traffic (for example, data for service control, data corresponding to a service, and the like). For example, the transmitted data may include a discovery reference signal (DRS), a PUCCH, a PUSCH, a PDSCH, or a PDCCH. The PDSCH is a channel used when the BS transmits data to the UE. The PUSCH is a channel used when the UE transmits data to the BS. The PDCCH indicates downlink resource allocation information, uplink resource allocation information, And is a channel for conveying the control information included. The DRS is also referred to as a discovery signal (DS) as a channel including control information for cell identification, channel quality measurement, and the like. Generally, the PDCCH can be transmitted in the same occupancy interval as the PDSCH through the occupied channel after the CCA. The CCA for the PDCCH may include a CCA for uplink grant transmission and a CCA for uplink data transmission. DRS can be transmitted over an independent CCA without PDCCH / PDSCH / PUSCH, and CCA can be performed in this case as well. Table 2 shows an example of a channel access method according to the traffic purpose. In this description, the base station can apply one of the channel access methods according to the traffic purpose described below, or can apply a combination of two or more. In Table 2, it is assumed that the priority of the channel access method is 1> 2> 3.

purpose Channel access method A typical example Service Control 1 One DRS Service Control 2 2 PDCCH Data transmission 3 PDSCH, PUSCH

- When the first traffic to which channel access method 1 is applied and the second traffic to which channel access method 2 or 3 apply are simultaneously transmitted, channel access may be attempted using channel access method 1 having the highest channel access probability have. When data is transmitted through at least one TTI included in the occupied channel after the CCA, the first traffic may be included in a predetermined number of TTIs (the first TTI or some TTI earlier than the predetermined number or ratio).

- When the first traffic to which channel access method 1 is applied and the second traffic to which channel access method 2 or 3 apply are simultaneously transmitted, a channel access attempt is made using channel access method 2 or 3 having a relatively low channel access probability . If channel access method 3 is used, all of the traffic corresponding to channel access methods 1, 2, and 3 within the allowed COT corresponding to channel access method 3 can be transmitted. If channel access method 2 is used, traffic corresponding to channel access methods 1 and 2 may be transmitted. In this case, when the channel occupation fails (when the channel is in use, etc.) or when the traffic transmission fails (transmission failure due to collision, etc.), the data corresponding to the channel access method with low probability is transmitted (or postponed) , Channel access may be retried using a high probability channel approach. For example, channel access method 1 is applied to occupy the channel, and transmission of the first traffic can be guaranteed. For example, different channel access methods may be used each time DRS and PDSCH (and / or PDCCH) are transmitted. For example, channel access method 1 is used when only DRS is transmitted, and channel access method 2 or 3 may be used when only PDSCH is transmitted. PDCCH and PDSCH may be transmitted when channel access method 2 is used, and only PDSCH when channel access method 3 is used. Channel access method 2 or 3 can be used even when DRS and PDSCH are transmitted simultaneously. In this case, if the channel access method 2 is used, the PDCCH and the PDSCH are transmitted together. If the channel access method 3 is used, only the PDSCH can be transmitted. (2) a channel access method with a high probability (for example, a channel access method 1) is performed in a case where a remaining CCA slot is generated due to failure of channel occupation, 1) a CCA is re- Can be used.

At this time, traffic to which different channel access methods are applied may be restricted from being transmitted at the same time.

- If the CCA slot is redetermined or adjusted, the contention window value of the previous CCA slot can be reused regardless of the channel access method corresponding to traffic transmitted since the last CCA. Or only traffic corresponding to the channel access method of the previously transmitted traffic channel access method can be transmitted. After a new attempt at channel occupancy, traffic corresponding to multiple channel access methods may be transmitted after the CCA performed by applying the highest or lowest channel access method.

On the other hand, when the CCA is performed to occupy a channel in the transmitting apparatus, the channel may not be occupied at a time required for data transmission (i.e., a time point when the channel is occupied). In 3GPP LTE, data is transmitted in units of subframes or slots or orthogonal frequency division multiplex (OFDM) symbols, so that subframes or slots in an occupied channel Or data may not be transmitted in an OFDM symbol.

FIG. 7 is a conceptual diagram illustrating a data transmission method according to the CCA end according to an embodiment.

Referring to FIG. 7, DRS that occurs periodically is used as an example of traffic transmitted after the CCA, but is not limited thereto (i.e., a data transmission method according to the end of CCA, which is described based on FIG. 7, A PUSCH, a subframe, a slot, an OFDM symbol, and the like).

Referring to FIG. 7, a BS transmits a DRS according to a predetermined period, and may perform a CCA before transmission of a DRS. If it is determined that the CCA result channel is occupied ("Idle"), the base station transmits the DRS, and if it is determined that the channel is occupied (busy or occupied), the base station retries the CCA. If it is determined that the channel after the re-attempted CCA can be occupied, the base station can transmit the traffic. In FIG. 7, the base station may perform the CCA according to the DRS measurement timing configuration (DMTC), and then transmit the DRS to the UE. That is, the BS can transmit the DRS in a period of a DMTC period, adjust the DMTC offset before the BS transmits the DRS, transmit the DRS during the DRS occasion duration, The duration is included in the DRS measurement duration (or DMTC window, hereinafter referred to as "DMTC window"). The base station can implement LBT because it performs CCA. The base station can perform at least one DRS transmission in the DMTC window of the occupied channel. If the base station fails to transmit DRS within the DMTC window due to channel conditions (eg, CCA time, maximum channel occupancy, etc.) (ie, if the DMTC window is terminated prior to transmission of the DRS) You can extend it.

Referring to FIG. 7A, a base station that fails to occupy a channel in the initial CCA performs CCA again, and transmits a DRS when the channel is determined to be idle. At this time, the re-execution of the CCA may be limited to the DMTC window or the number of re-execution may be limited.

Referring to (b) of FIG. 7, since the CCA is occupied by the channel, the base station retries the CCA, and the base station can advance the next CCA time a little as compared to FIG. 7 (a). For example, the base station can arbitrarily select a CCA execution time according to a predetermined CCA execution time, and the channel occupancy probability can be increased. Also, the base station can prevent channel occupation of other devices (LBT earlier & transmit "R") by transmitting an "R" signal (R? 0) until the CCA transmits data. At this time, when the maximum size (or maximum time) of the "R" signal is limited, the transmitting apparatus adjusts the CCA execution time so that the "R" signal can be transmitted before data transmission, Thereafter, additional CCA can be performed.

In the present description, the transmitting apparatus can determine the CCA start time (T _s ) in consideration of the executable time (T _c ) of the CCA so that the CCA can be completed before the data transmission time (T _d ). The relationship between the data transmission time (T _d ), the CCA executable time (T _c ), and the CCA starting time (T _s ) is shown in Equation (6).

On the other hand, when the transmitting apparatus fails to terminate the CCA until the data transmission time, the transmitting apparatus can not transmit data at the time of data transmission. Referring to (c) of 7, the transmitting device may transmit the data after the user when it is determined that the channel is idle CCA result, occupies a channel to the next then T _d Td. The CCA may be omitted until the next T _d (LBT & shift the DRS till next DRS occasion). In the case of (c) of FIG. 7, the channel occupancy of the base station may be limited within the DMTC window or the number of times may be limited. At this time, the BS may transmit the "R" signal to the next T _d. Alternatively, if the CCA is not terminated at the time of DRS transmission, the base station may skip transmission of the corresponding DRS and re-execute the CCA before the next DRS transmission time.

Referring to FIG. 7 (d), the base station may shift the data transmission time T _d . At this time, the shift of the data transmission time may be limited within the DMTC window, or the number of times may be limited.

On the other hand, the DRS can be transmitted in any subframe (including subframe 0 or subframe 5) in the DMTC. Hereinafter, a method of generating a sequence of signals constituting a DRS such as PSS, SSS, CRS, and CSI-RS and a method of indicating information about a data burst of an occupied channel will be described in detail.

A primary synchronization signal (PSS) required for data transmission between a base station and a terminal is transmitted in subframe 0 in FDD, subframes 1 and 6 in TDD, and a secondary synchronization signal (SSS) is transmitted in subframe 0 And 5, respectively. A cell-specific reference signal (CRS) is transmitted in each downlink subframe, and a channel state information reference signal (CSI-RS) is transmitted in a predetermined subframe. However, PSS, SSS, CRS, and CSI-RS may be transmitted in different subframes, depending on the variety of channel occupancy according to the CCA performed for operation in the license-exempt band or DRS transmission in the DMTC window.

Accordingly, when an SSS included in a DRS is transmitted to subframes other than subframes 0 and 5, 1) an SSS sequence transmitted in subframes 0 and 5 is used, or 2) an SSS is newly generated for DRS use . The two SSS generation methods described below can be combined with each other. In each method, the SSS consists of a sequence of 62 lengths.

- Sequence Generation Method of SSS 1: A method of generating a sequence constituting an SSS transmitted in subframes other than subframes 0 and 5 based on Equation (7).

That is, in the SSS sequence generation method 1, the SSS may be generated according to a sequence generation method defined for each of the subframe 0 or the subframe 5. Therefore, the terminal receiving the SSS can detect the SSS through the SSS detection method corresponding to the subframe 0 or 5 when the SSS is detected, and acquires the cell ID (Cell ID) based on the detection result of the SSS .

- Sequence generation method of SSS 2: A method of independently generating a sequence of SSSs transmitted in subframes other than subframes 0 and 5, for each subframe number of another subframe in which SSS is transmitted.

According to the sequence generation method 2 of the SSS, the DRS or the initial signal transmitted in the license-exempt band (for example, a signal that the transmitting apparatus succeeds in occupying the channel after the CCA and transmits the data before transmitting the data) 0 and &lt; RTI ID = 0.0 &gt; 5, &lt; / RTI &gt;

If the SSS is transmitted in subframes other than subframes 0 and 5, transmission of CRS, CSI-RS, DM-RS, etc. may occur simultaneously with SSS transmission. That is, the SSS, the PSS, the CRS, the CSI-RS, and the DM-RS can be transmitted in the subframe 0 or the subframe 5 and other subframes. At this time, the CSI-RS can be transmitted when it is preset through upper layer signaling, and the DM-RS can be included in the PDSCH when the PDSCH is transmitted. That is, the DM-RS is not transmitted in a subframe transmitted only by the DRS without the PDSCH.

The sequence of CRS, CSI-RS, DM-RS, etc. may be generated through one or more of the methods described below.

Method 1: A CRS, a CSI-RS, and a DM-RS are generated based on a slot number included in a subframe 0 or a subframe 5.

- Method 2: Unlike the SSS, CRS, CSI-RS, and DM-RS are generated based on the slot number included in the subframe in which the CRS, CSI-RS, and DM-RS are transmitted.

In method 2, CRS, CSI-RS, and DM-RS and PSS and SSS are transmitted in the same subframe (i.e., subframe other than subframe 0 or subframe 5) 5, and CRS, CSI-RS, and DM-RS are generated based on the slot numbers included in the subframe numbers in which CRS, CSI-RS, and DM-RS are transmitted do. At this time, the SSS, CRS, CSI-RS, and DM-RS can be transmitted through some OFDM symbol (i.e., partial subframe) among a plurality of OFDM symbols included in one subframe. For example, DRS can be transmitted over 12 OFDM symbols included in one subframe.

Data may be transmitted in other subframes other than the subframe in which the DRS is transmitted and the DRS is transmitted in at least one subframe other than the subframe 0 or the subframe 5 in the DRS operation. For example, if the base station occupies a channel through the CCA in subframe 1 in the DRS operation, the base station transmits the DRS in subframe 2 and the remaining subframes (subframe 3 and subframe 4 ), Or can (re-) transmit DRS.

When the channel occupancy is limited according to the frequency operation regulation, the transmitting apparatus can instruct the receiving apparatus, or the receiving apparatus can instruct the time length of the channel occupied by the transmitting apparatus as follows and exchange data.

First, a receiving apparatus of a sequence can determine a channel occupation time through a sequence generated based on a limited channel occupancy. Table 3 shows a method of expressing channel occupation time in units of slots, and Table 4 shows a method of expressing channel occupation time in units of subframes (or TTI units).

Referring to Table 3 and Table 4, the information on the channel occupation time is generated by a pseudo-random sequence generator that generates a reference signal (CRS, CSI-RS, DM-RS, etc.) May be included in the initial value (C _init ) of the random sequence. Therefore, the receiving apparatus that receives the reference signal can identify the channel occupation time through the initial value of the random sequence. Table 5 shows a method of expressing the channel occupation time in a slot unit when the DRS + PDSCH is transmitted, and Table 6 shows a method of representing the channel occupation time in units of a subframe (or TTI) when the DRS + PDSCH is transmitted .

first
slot second
slot third
slot Fourth slot ... n-1 th
slot nth
slot Remarks Method S1 k k-1 k-2 k-3 ... k- (n-2) k- (n-1) The current slot is the number of the slot in the COT. Method S2 F (= 01) I (= 10) I (= 10) I (= 10) ... I (= 10) L (= 11) Determined by whether the slot is first (F), middle (I), last (L) Method S3 L (= O) L (= O) L (= O) L (= O) ... L (= O) L (= 1) Decided by the last slot Method S4 P (= O) P (= O) P (= O) P (= O) ... P (= 1) P (= 1) Determined by whether the slot is a partial slot

first
serve
frame second
serve
frame third
serve
frame fourth
serve
frame ... (n-1) th
serve
frame Nth
serve
frame Remarks Method T1 k k-1 k-2 k-3 k- (n-2) k- (n-1) The current subframe is the subframe number within the COT. Method T2 F (= 01) I (= 10) I (= 10) I (= 10) I (= 10) L (= 11) It depends on whether the subframe is the first (F), the middle (I), or the last (L) Method T3 L (= O) L (= O) L (= O) L (= O) L (= O) L (= 1) Determined by whether the subframe is last Method T4 P (= O) P (= O) P (= O) P (= O) P (= O) P (= 1) Determined based on whether the subframe is a partial slot

DRS Remarks first
slot second
slot third
slot Fourth slot ... n-1 th
slot nth
slot Method S11 k k-1 k-2 k-3 ... k- (n-2) k- (n-1) The current slot is the number of the slot in the COT. Method S12 F (= 01) I (= 10) I (= 10) I (= 10) ... I (= 10) L (= 11) Determined by whether the slot is first (F), middle (I), last (L) Method S13 L (= O) L (= O) L (= O) L (= O) ... L (= O) L (= 1) Decided by the last slot Method S14 P (= O) P (= O) P (= O) P (= O) ... P (= O) P (= 1) Determined by whether the slot is a partial slot

first
serve
frame second
serve
frame third
serve
frame
(DRS) fourth
serve
frame ... (n-1) th
serve
frame Nth
serve
frame Remarks Method T11 k k-1 k-2 k-3 ... k- (n-2) k- (n-1) The current subframe is the subframe number within the COT. Method T12 F (= 01) I (= 10) I (= 10) I (= 10) ... I (= 10) L (= 11) It depends on whether the subframe is the first (F), the middle (I), or the last (L) Method T13 L (= O) L (= O) L (= O) L (= O) ... L (= O) L (= 1) Determined by whether the subframe is last Method T14 P (= O) P (= O) P (= O) P (= O) ... P (= O) P (= 1) Determined based on whether the subframe is a partial slot

Referring to Tables 3 to 6, the reference signal receiving apparatus can determine the channel occupation time based on the current slot or subframe.

- Method S1, S11, T1, and if at T11, which is CCA after channel occupation time n [ms] (n single TTI, n sub-frames, such as 2n-slot), the first slot n _s is k, two a second slot of the n _s k-1, the third slot of the n _s k-2, n _s of the last slot can be set to kn. Or n _s is set to an existing slot number index (or sub-frame number index) and one of k-1, k-2, ..., kn is made to correspond to each slot separately from n _s , The channel occupation time of the channel to be occupied or the channel occupation time of the channel to be occupied in the future. At this time, k may be set to the maximum occupancy time, the occupied time n for transmitting the current data, or any number. If k = n, prediction of a subframe / slot to be transmitted after the current subframe / slot may be possible.

- In the methods S2, S12, T2 and T12, information indicating which slot or subframe of the occupied channel the current slot or subframe corresponds to (i.e., the first, middle, as information indicating that the last slot or subframe) n _s is replaced or, or above, the information may be included in the C _init independently of n _s.

- how to S3, S13, T3, and at T13, as the last slot or sub-frame information to any indication of the channel currently slot or sub-frame occupied separately from or n _s is replaced, or the above information n _s C _init .

- If a signal similar to DRS or DRS (for example, SSS) is transmitted, Method 1 and Method 2 described above can be applied. For example, when a signal similar to DRS or DRS is included, a sequence of each slot included in the corresponding subframe is generated using _ns (= 0, 1) (or _ns = 0) of C _init , For the other subframes and slots, the sequence generation method described above can be applied.

Alternatively, a sequence generated based on the limited channel occupancy or a sequence generated based on the same sequence may be mapped to a resource element (RE) through Equation (8) below. According to Equation (8), each sequence mapped to a resource element can be distinguished for each slot and subframe.

Meanwhile, in one embodiment, when the last subframe of the occupied channel is a partial subframe, the communication apparatus can inform the counterpart communication apparatus of information on the partial subframe through the following method.

The length of the partial subframe may be set via a radio resource control (RRC) message or may be set in advance between communication devices. At this time, a value indicating the length of the partial sub-frame may be further defined. For example, a subframe indicated as P = 1, such as methods S4, S14, T4, and T14, is indicated as a partial subframe, and the communication device can use the indicated partial subframe. A subframe indicated as P = 0 may be indicated as being a normal subframe.

If more than one partial subframe is used, a value indicating the length of the partial subframe may be added. For example, when four partial subframes are used, 00, 01, 10, and 11 may be used as values capable of expressing the length of the partial subframe, and may be used in the form of "P + length value ". By using such a partial sub-frame, "P = 0" can be expressed even when the channel is occupied and usable. And "P = 0 ", the length of the partial subframe can be ignored.

Information about the use of the partial sub-frame and the length value of the partial sub-frame may be included in the above-described sequence, or included in a previously defined channel (e.g., PCFICH, DCI, PHICH, etc. in the PDCCH) . Information on whether or not the partial subframe is used and the length value of the partial subframe are included in the physical HARQ indicator channel (PHICH), instead of HARQ ACK / NACK.

When information on the use of the partial subframe and the length value of the partial subframe are included in the physical control format indicator channel (PCFICH), the portion representing the OFDM symbol length of the PDCCH is represented by RRC signaling Or may be represented immediately before the portion indicating the starting position of the PDSCH and the EPDCCH. Information on whether to use the partial subframe and length values of the partial subframe can be included in the PCFICH only when the partial subframe is applied to all the subframes. In addition, the portion for the PDCCH in the PCFICH may be limited to one or two OFDM symbols. At this time, if the portion related to the PDCCH is limited to one or two OFDM symbols, the PHICH period of the extended PHICH period of the PHICH duration may be set to 1 or 2, or may be set to 3. If the PHICH period is 3, the PHICH period may be instructed by the terminal to be recognized as two. This is similar to the configuration of DwPTS.

Information on the use or non-use of the partial sub-frame and the length value of the partial sub-frame are included in the PDCCH, the information on the use of the partial sub-frame and the length value of the partial sub- May be included as common downlink control information (DCI) in a common search space.

On the other hand, in the partial sub-frame, only the partial sub-frame composed of a case where the DRS is longer than the predetermined length may be transmitted, or DRS may not be transmitted in the partial sub-frame.

8 is a conceptual diagram illustrating a channel access method of a multi-carrier network according to an embodiment.

In Fig. 8, a transmitting apparatus accesses a channel operated by multiple carriers for data transmission. Referring to FIG. 8, the transmitting apparatus performs the CCA through the first SCell. Then, the transmitting apparatus performs a CCA, and then transmits a concurrent transmission boundary (LBT) at a predetermined time (for example, a point coordination function inter-frame space (PIFS) (time to synchronous transmission boundary (STB)), and can transmit data in the first SCell and the second SCell. Referring to FIG. 8, the channels of the third SCell and the fourth SCell are occupied by other devices (for example, WiFi band devices, etc.) operating in the license-exempt band, and are not used for data transmission of mobile communication. In this case, the transmitting device can perform CCA on only one channel, and can use other channels simultaneously, such as the channel of the second SCell, through additional sensing. Other devices can use the channels of the third SCell and the fourth SCell because the transmitting device does not perform the CCA for another channel such as the channels of the third SCell and the fourth SCell. That is, the transmitting apparatus can perform the CCA only for one channel, and can detect whether or not the other channel is occupied through additional sensing after the CCA. Below, a transmitting device accesses / occupies a channel to transmit data, and a receiving device accesses / occupies a channel to receive data. Hereinafter, the case where the transmitting apparatus performs the CCA and the case where the receiving apparatus performs the CCA are explained, but the present invention is not limited thereto.

9 is a conceptual diagram illustrating a channel access method of a multi-carrier network according to another embodiment.

Referring to FIG. 9, the communication apparatus performs CCA for each carrier, and can exchange (transmit and receive) data through multiple channels according to the CCA result. At this time, the communication device performs channel sensing for a predetermined time (e.g., 'Self-deferral + 1 CCA slot' in FIG. 9) in the CCA-congestible channel, Can wait for the end of CCA.

Referring to FIG. 9A, the CCAs of the first SCell and the second SCell terminate before the CCAs of the third SCell and the fourth SCell. Therefore, the communication apparatus performs channel sensing after the CCA is terminated before the data transmission time so that the data transmission time points in the first SCell to the fourth SCell can be all matched.

Referring to FIG. 9B, while the CCA of the first SCell and the second SCell is terminated and the communication device performs channel sensing before the data transmission time, a carrier whose CCA is not terminated before the LSB ) Or a carrier (fourth SCell) in which it is determined that channel occupation is impossible without ending the CCA may occur. In this case, the communication apparatus may not use the first SCell and the second SCell for data transmission. At this time, when the channel interval between the second SCell and the third SCell is smaller than a predetermined interval (for example, in MHz), the communication device ends the CCA of the third SCell and terminates or terminates the channel occupation for the second SCell The CCA can be performed again. However, if the time from the CCA end point to the LSB (or STB) for the first SCell and the second SCell is relatively long, another license-exempt band device may use the carriers of the first SCell and the second SCell.

If the CCA is not terminated before the start of STB even after other license-licensed band devices occupy the channel during the CCA as in the third SCell of FIG. 9 (b) If the CCA does not terminate during the PIFS interval (e.g., the self-differential +1 CCA slot 20us) after the occupancy is terminated, the communication device may only operate the first SCell and the second SCell with multiple carriers That is, the communication device may not use the third SCell as a data transmission carrier.

On the other hand, if the CCA end point of time of the first SCell and the second SCell is earlier than the CCA end point of the third SCell and the fourth SCell, the additional channel sensing period of the communication device is longer than the predetermined time, . The predetermined time may be a defer period DP and the DP may be defer duration (DD) +1 CCA slot or PIFS. In this case, the DP and PIFS are DP &gt; PIFS &gt; 0 or PIFS? DP? 0.

10 to 12 are conceptual diagrams illustrating a channel access method of a multi-carrier network according to another embodiment.

Referring to FIG. 10, after the CCA ends for the first SCell and the second SCell, the communication device does not sense the channel for the time until the CCA ends for the third SCell and the fourth SCell, In order to prevent the first SCell and the second SCell from being occupied by the apparatus, a special signal R (R? 0) is transmitted in the first SCell and the second SCell. Thereafter, the communication device senses the channel during the DP in the first SCell to the fourth SCell, and then starts data transmission at the STB time.

Referring to FIG. 11, after the communication device completes the CCA for the first SCell to the fourth SCell, it senses the channel during the DP and transmits the special signal R in the first SCell and the second SCell that terminated the CCA first . In other words, the communication apparatuses in FIGS. 10 and 11 can synchronize the data transmission times of the carriers through the transmission of the special signal R.

Referring to FIG. 12, the CCAs for the third SCell and the fourth SCell do not end during the DP for the first SCell and the second SCell. In this case, when the additional channel sensing of the first SCell and the second SCell is completed, the communication device transmits data using the carriers of the first SCell and the second SCell. Thereafter, when the channel occupation time for the first SCell and the second SCell has not expired, the communication apparatus uses the carriers of the first SCell to the fourth SCell at the point of time when the DP for the third SCell and the fourth SCell is terminated Data can be transmitted.

Hereinafter, a license-exempted bandwidth channel access method for multi-cell operation will be described with reference to FIG. 13 through FIG.

13 is a conceptual diagram illustrating a multi-cell network according to an embodiment.

Referring to FIG. 13, when a plurality of base stations or access points (APs) included in a multi-cell network access a channel of a license-exempt band and occupy a channel to transmit data, each communication device performs a CCA The CCA parameters (e.g., CCA slot, energy detection level, DP, etc.) applied may be the same. However, due to the spatial difference in the sensing area where each communication device performs the CCA, the energy of the channel can be measured differently. In this case, only some devices access the channel to occupy the channel, and the other device judges that the channel is in use, and the countdown of the CCA slot can be interrupted (CCA slot freeze). In this case, another device that fails to access the channel measures the energy of the channel again and checks whether the channel is occupied. That is, although a plurality of communication apparatuses perform CCA applying the same parameters, channel access can not be performed simultaneously with another license-exempt band apparatus due to the execution of CCA. Hereinafter, a method for simultaneously performing channel access by a plurality of communication apparatuses performing CCAs using the same CCA parameter will be described.

By performing the CCA applying the same CCA parameters, each communication apparatus can perform channel access simultaneously, if it is before the execution of the CCA.

14 to 16 are conceptual diagrams illustrating a channel access method in a multi-cell network according to an embodiment.

Referring to FIG. 14A, the first base station LAA eNB 1 and the second base station LAA eNB 2 transmit information about the CCA end, such as the end of the CCA or the end of the CCA, To the base station (the third base station LAA eNB 3 and the fourth base station LAA eNB 4). Then, the base stations (the first base station and the second base station) that terminate the CCA perform additional sensing during the predetermined self-differential interval. The base stations (the third base station and the fourth base station) that have received the information on the end of the CCA terminate the CCA in the self-differential interval and perform additional sensing. At the same time, when information about a time point (STB) for starting a service is preset and shared between each base station, each base station can perform self-deferring up to the STB. At this time, at least one CCA slot may be included after the self-differential, or at least one CCA slot may be included in the self-differential. The first base station and the second base station have a self-differential interval longer than the DP, so that the first base station and the second base station transmit the special signal R as shown in FIGS. 15 (a) and 15 (b) And concurrent channel access with the fourth base station. In FIG. 15A, the first base station and the second base station transmit Rs before DD, and in FIG. 15B, the first base station and the second base station transmit Rs after DD.

Referring to FIG. 14 (b), the third base station and the fourth base station can not complete the CCA because of the other license-exempt band devices. While the third base station's CCA is in use, the other license-exempt band device used the channel, and the fourth base station's CCA was not terminated. At this time, the base stations (the third base station and the fourth base station) that have not completed the CCA can transmit information on the freezed CCA slot to the other base stations (the first base station and the second base station) during the CCA. At this time, the information about the freezed CCA slot can be transmitted to the other base station at the time of freezing or at the time of restarting the countdown. The third base station and the fourth base station can perform the CCA and occupy the channel separately from the first base station and the second base station when the time length of the remaining CCA slot is longer than the self-differential interval. That is, in this case, concurrent channel access is performed only for the first base station and the second base station.

Referring to FIG. 16, a plurality of STBs can be set. When the CCAs of some base stations (the third base station and the fourth base station) are terminated after the first STB, all the base stations (the first base station, the second base station, the third base station and the fourth base station) After occupying the channel, data can be transmitted at the same time. That is, data can be transmitted simultaneously in the next STB. In this case, the next STB may be located after an additional sensing interval of the third base station and the fourth base station, and a period after the CCA of the third base station and the fourth base station is set to a period (for example, CCA slot, etc.).

On the other hand, in the case of discontinuous reception (DRX), the communication device can access the channel in a plurality of different ways. 17 is a conceptual diagram illustrating a channel access method when DRX is performed according to an embodiment.

Referring to FIG. 17, the DRX performed by the communication device includes an on duration and an off duration (e.g., opportunity for DRX). During the off period, the terminal monitors the (E) PDCCH. In the ON period, the base station and the terminal can perform a procedure for data transmission and reception. For example, the terminal can receive the (E) PDCCH for data transmission / reception in the ON period. The base station needs to perform the CCA to transmit the PDCCH through the license-exempt band, and the terminal also needs to perform the CCA in order to transmit / receive data according to the reception result of the (E) PDCCH. That is, the channel access method according to the DRX described below is a method of transmitting data to a transmitting apparatus (for example, a receiving apparatus) that attempts to transmit data to a receiving apparatus (for example, a downlink terminal, an uplink base station, For example, a base station of a downlink, a terminal of an uplink, and a transmitter in the case of exchanging data between apparatuses), and can also be applied to a receiver that receives data from a transmitter.

17 (a), (b), (c), (d), (e), (f), and (g) show channel access methods in the vicinity of the on- ), (x), (y), and (z) represent the channel access method in the vicinity of the end of the on period. The base station can transmit and receive data to and from the terminal corresponding to the ON period when the channel is occupied and performs the CCA for channel occupation when the channel is not occupied. The communication device performs the CCA and sets the starting point of the ON period after the end of the CCA to the starting point of the ON period after the end of the CCA (i.e., one or two OFDM symbols, one slot, (Fig. 17 (a), (b), (c), (d), and (e)).

At this time, the special signal R may be transmitted within the ON period, for synchronization for data exchange and for preventing access to other license-exempt band devices (FIG. 17A, FIG. 17B). Or the special signal R may be transmitted before the on period and used for time synchronization up to the on period (Fig. 17 (c), (d)).

Referring to FIG. 17 (f), when the communication device does not perform the LBT before the ON period, the CCA is performed after the ON period, and the special signal R indicates the method set to the receiving device, .

Referring to FIG. 17 (g), when the license-exempted band is occupied and used by another license-exempt band device (serving base station, WiFi device, etc.) when transitioning from the ON period to the OFF period, the base station 1) The data exchange is not expected at the time of transition from the off period to the on period, or 2) the special signal R is exchanged for every data exchange Frame (or TTI).

On the other hand, when the time from the CCA to the data exchange is included in the off period, the base station 1) performs additional sensing (DP), or 2) transmits the special signal R, or 3) And data can be exchanged. When the base station exchanges data with other terminals corresponding to the ON period, the mobile station can exchange (E) PDCCH for data exchange and exchange data only during the ON period of the specific UE according to a DRX cycle set for each UE.

If the maximum channel occupancy time due to the license-exempt band frequency regulation expires in the entire period, the CCA for channel access may be additionally performed. The time point at which the ON period is terminated and the OFF time period (opportunity for DRX) starts (the time point from the ON period to the OFF period is shown to the terminal) as shown in (w), (x), (y) Which may be preset), a combination of one or more of the following methods may be indicated to the receiving device.

- &gt; (Fig. 17 (z)), the CCA for channel access may not be performed at the time of transition from the ON period to the OFF period.

- If the CCA for channel access is completed within a predetermined time before the transition, the channel occupation can be extended to the off period by the channel occupancy time determined through the CCA (FIG. 17 (y)).

The channel is occupied by the CCA in the ON period, and if the start time of the OFF period comes before the maximum channel occupation time is reached, 1) the data transmission is stopped (Fig. 17 (x) Or 2) extend the on period by an increased time for the maximum channel occupancy time and postpone the transition to the off period (FIG. 17 (w)). If the transition point to the OFF period is delayed, the DRX cycle may be readjusted so that the next ON period is also delayed as the start point of the OFF period is delayed. Alternatively, the DRX cycle can be maintained at its original setting irrespective of the postponement of transition to the off period.

18 is a conceptual diagram illustrating a channel access method when DRX is performed according to another embodiment.

18 shows a method of operating the license-exempt multi-carrier within the ON period. Referring to FIG. 18, the DRX performed by the communication device includes an on duration and an off duration (e.g., opportunity for DRX). The base station and the terminal can perform a procedure for data transmission and reception. For example, the terminal can receive the (E) PDCCH for data transmission / reception in the ON period. The base station needs to perform the CCA to transmit the PDCCH through the license-exempt band, and the terminal also needs to perform the CCA in order to transmit / receive data according to the reception result of the (E) PDCCH. In addition, in order for multiple carriers to operate on the DRX cycle, one or more combinations of multiple carrier operating methods in the license-exempt band described with reference to FIG. 17 can be applied to each carrier. At this time, the DRX cycle may be operated independently for each carrier, or may be commonly used for multiple carriers.

When the common DRX cycle is operated, when the CCA is changed to the on period from the off period to the on period as shown in (a) of Fig. 18, the power of the terminal can be saved have. If the ON period after the CCA corresponds to the OFF period of the UE, the BS may perform additional sensing until the ON period of the UE, such as DP (or self-differential, PIFS), or may transmit the special signal R. At this time, data exchange after the CCA can be performed in the ON period.

19 is a block diagram illustrating a wireless communication system according to an embodiment.

Referring to FIG. 19, a wireless communication system according to an embodiment includes a base station 1910 and a terminal 1920.

The base station 1910 includes a processor 1911, a memory 1912, and a radio frequency unit (RF unit) 1913. The memory 1912 may be coupled to the processor 1911 to store various information for driving the processor 1911 or at least one program executed by the processor 1911. [ The wireless communication unit 1913 is connected to the processor 1911 to transmit and receive a wireless signal. The processor 1911 may implement the functions, processes, or methods proposed in the embodiments of the present disclosure. At this time, in the wireless communication system according to the embodiment of the present invention, the wireless interface protocol layer can be implemented by the processor 1911. The operation of base station 1910 according to one embodiment may be implemented by processor 1911.

The terminal 1920 includes a processor 1921, a memory 1922, and a wireless communication unit 1923. [ The memory 1922 may be coupled to the processor 1921 to store various information for driving the processor 1921 or at least one program executed by the processor 1921. [ The wireless communication unit 1923 is connected to the processor 1921 to transmit and receive wireless signals. The processor 1921 may implement the functions, steps, or methods suggested in the embodiments of the present disclosure. At this time, in the wireless communication system according to the embodiment of the present invention, the wireless interface protocol layer can be implemented by the processor 1921. The operation of terminal 1920 according to one embodiment may be implemented by processor 1921. [

In an embodiment of the present disclosure, the memory may be located inside or outside the processor, and the memory may be connected to the processor through various means already known. The memory may be any type of volatile or nonvolatile storage medium, e.g., the memory may include read-only memory (ROM) or random access memory (RAM).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (19)

Claims 1. A receiving apparatus for receiving a signal via a license-exempt band,
A processor, a memory, and a wireless communication unit,
Wherein the processor executes a program stored in the memory,
A secondary synchronization signal (SSS) is generated in at least one remaining subframe except a subframe 0 or a subframe 5 among a plurality of subframes included in a discovery signal measurement timing configuration (DMTC) ; And
Detecting the sub-frame signal using the sub-frame number of the sub-frame 0 or the sub-frame 5
. The method of claim 1,
The auxiliary sync signal is composed of a sequence of length 62 generated using the following equation,
[Mathematical Expression]

Wherein the DMTC comprises the subframe 0, 1, 2, 3, 4 or the subframe 5, 6, 7, 8, 9. The method of claim 1,
Wherein the processor executes a program stored in the memory,
Acquiring a cell identification (Cell ID) based on the detection result of the auxiliary synchronization signal
Further comprising: The method of claim 1,
The processor, when performing the step of receiving the auxiliary synchronization signal,
Receiving the auxiliary sync signal in a first sub-frame of the at least one remaining sub-frame
Lt; / RTI &gt;
Wherein the processor executes a program stored in the memory,
Receiving data in a next sub-frame of the first sub-frame among the remaining sub-frames
Further comprising: The method of claim 1,
The processor, when performing the step of receiving the auxiliary synchronization signal,
Receiving the auxiliary synchronization signal, the primary synchronization signal (PSS) and the cell-specific reference signal (CRS) in a first sub-frame of the remaining sub-frames
. The method of claim 5,
When performing the step of receiving the auxiliary synchronization signal, the main synchronization signal, and the cell specific reference signal,
Receiving a channel state information-reference signal (CSI-RS)
Further comprising: The method of claim 5,
Wherein the auxiliary synchronization signal, the main synchronization signal, and the cell specific reference signal are received in 12 orthogonal frequency division multiplex (OFDM) symbols included in the first subframe. The method of claim 5,
The processor executing the program stored in the memory,
Detecting the cell-specific reference signal using a slot number of a slot included in the first sub-frame
Further comprising: Claims [1] A transmitting apparatus for transmitting data via a license-
A processor, a memory, and a wireless communication unit,
Wherein the processor executes a program stored in the memory,
Receiving a hybrid automatic retransmission request (HARQ) ACK / NACK corresponding to a physical downlink shared channel (PDSCH)
Increasing a contention window value of a contention window for accessing the channel if the number of HARQ NACKs is greater than a number of the HARQ ACKs by a predetermined ratio;
Performing a channel access procedure based on the increased contention window value
. The method of claim 9,
Wherein the processor executes a program stored in the memory,
Decreasing the contention window value if the number of HARQ ACKs is greater than the number of HARQ NACKs by a predetermined ratio; and
Performing a channel access procedure based on the reduced contention window value
And performs a further processing. The method of claim 9,
Wherein the processor performs a channel access procedure based on the increased contention window value,
Performing a clear channel assessment (CCA) or extended CCA (ECCA) based on the increased contention window value
. The method of claim 9,
The processor, when performing the step of receiving the HARQ ACK / NACK,
Receiving HARQ ACK / NACK corresponding to the PDSCH of the first subframe included in the channel occupancy time (COT) for the channel
. The method of claim 9,
Wherein the processor executes a program stored in the memory,
Instructing the receiving device to update the increased contention window value or the contention window value
And performs a further processing. Claims [1] A transmitting apparatus for transmitting traffic through a license-
A processor, a memory, and a wireless communication unit,
Wherein the processor executes a program stored in the memory,
Transmitting traffic corresponding to a second priority class lower than the first priority class used for channel access, and
Transmitting traffic corresponding to a third priority class higher than the first priority class after all the traffic corresponding to the second priority class is transmitted
. The method of claim 14,
Wherein the energy detection thresholds corresponding to the first priority class, the second priority class, and the third priority class are different from each other. The method of claim 14,
Wherein the traffic corresponding to the second priority class is a discovery reference signal (DRS) or a discovery signal, and the traffic corresponding to the third priority class is a physical downlink shared channel channel, PDSCH). The method of claim 14,
Wherein the first priority class, the second priority class, and the third priority class are determined according to the type of the traffic. The method of claim 14,
Wherein the processor executes a program stored in the memory,
Performing the channel access based on a clear channel assessment (CCA) parameter determined according to the first priority class, the second priority class, and the third priority class
And performs a further processing. The method of claim 14,
A different channel occupation time is set in the second priority class and the third priority class, respectively,
Wherein the processor executes a program stored in the memory,
And transmits the traffic for a channel occupancy time corresponding to the second priority class when transmitting traffic corresponding to the second priority class.

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