KR20150012805A - Method and apparatus for managing soft buffer for device-to-device communication in wireless communication system - Google Patents

Abstract

Disclosed are a method and an apparatus for managing soft buffer for device-to-device communication in a wireless communication system. A terminal transmits terminal information which includes the size of a soft buffer and the support of device-to-device communication to a base station, and receives generated control information based on the terminal information from the base station and then separates the soft buffer based on the control information.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a soft buffer management method and apparatus for communication between devices in a wireless communication system,

The present invention relates to a soft buffer management method and apparatus for direct communication between devices in a wireless communication system. More particularly, when a terminal receives a discovery channel using channel coding, And to a method for enabling reception of a number of discovery channels.

The present invention also relates to a method for efficiently managing a memory for demodulating a data channel received by a terminal from a base station, demodulating a data channel for communication between terminals, and demodulating a discovery channel.

Generally, a mobile communication system is developed for providing communication while securing the mobility of a user. Such a mobile communication system has reached a stage where it can provide high-speed data communication services as well as voice communication owing to the remarkable development of the technology.

Recently, as one of the next generation mobile communication systems, standard works for Long Term Evolution (LTE) -Advanced systems are underway in the 3rd Generation Partnership Project (3GPP). The LTE-Advanced (LTE-A) system has been developed for continuous performance improvement, and is a technology for implementing high-speed packet-based communication with a transmission rate of 3 to 10 times higher than the data transmission rate currently provided.

In addition, direct communication between terminals, that is, D2D (Device to Device), has been continuously studied since the beginning of 2000. In the current mobile communication system, a wireless network of a base station and a wired network The inter-terminal communication has been studied to reduce such load and to support effective communication between adjacent terminals even in the absence of a wireless network. In addition, inter-terminal communication for effective communication in a situation where a base station does not exist or a base station does not operate due to an emergency disaster has been studied.

Hereinafter, the LTE system will be understood to include the existing LTE system and the LTE-A system.

In order to simultaneously perform wireless communication between the base station and the terminal and direct communication between the terminals in the system, in order for the terminal to receive the data channel from the base station and to perform inter-terminal communication, the discovery channels transmitted by the terminals for inter- And receive data channels transmitted by the UE. However, since the terminal has a limitation on the size of the memory or the buffer for storing the demodulated symbol for receiving the data channel, it can demodulate hundreds or thousands of discovery channels and effectively manage the memory or buffer of the terminal receiving the data channel between the terminals Is required.

According to another aspect of the present invention, there is provided a method for managing a soft buffer of a terminal for inter-device communication in a wireless communication system, the method comprising the steps of: Transmitting information; Receiving control information generated based on the terminal information from the base station; And dividing the soft buffer based on the control information.

According to an aspect of the present invention, there is provided a method of providing information of a base station for soft buffer management of a terminal in a wireless communication system, the method comprising the steps of: Receiving terminal information from the terminal; Transmitting control information generated based on the terminal information to the terminal; And transmitting scheduling information for transmitting downlink data to the MS.

According to an aspect of the present invention, there is provided a terminal for managing a soft buffer for communication between devices in a wireless communication system, the terminal including: a transceiver for transmitting and receiving signals to and from a base station and a terminal supporting communication between the devices; And transmitting, to the base station, terminal information including a size of the soft buffer and support for communication between the apparatuses, receiving control information generated based on the terminal information from the base station, And a controller for dividing the soft buffer.

According to an aspect of the present invention, there is provided a base station for providing information for soft buffer management of a terminal in a wireless communication system, the base station comprising: a wireless transceiver for transmitting and receiving signals to and from the terminal; And receiving terminal information including the size of the soft buffer of the terminal and support of inter-device communication from the terminal, transmitting the control information generated based on the terminal information to the terminal, and transmitting the downlink data And a control unit for transmitting scheduling information for transmitting the scheduling information.

According to the soft buffer management method and apparatus for communication between devices in the wireless communication system according to the embodiment of the present invention, a soft buffer memory of a limited size can be efficiently utilized.

1 is a diagram illustrating a system for communication between terminals in a communication system for transmitting and receiving data between a base station and a terminal,
2 shows a downlink sub-frame,
3 is a diagram illustrating an uplink sub-frame,
4 is a diagram illustrating a discovery channel region of an uplink radio frame applied in the present invention,
5 is a diagram for explaining a method in which a UE manages a soft buffer for a data channel in an LTE system,
FIG. 6 is a diagram for explaining a soft buffer management method for inter-terminal communication according to the first embodiment of the present invention; FIG.
FIG. 7 is a diagram for explaining a soft buffer management method for inter-terminal communication according to a second embodiment of the present invention; FIG.
8 is a diagram illustrating an operation of a base station according to an embodiment of the present invention,
9 is a diagram illustrating an operation of a terminal according to an embodiment of the present invention;
10 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention,
11 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

While the embodiments of the present invention will be described in detail, the OFDM-based wireless communication system, especially 3GPP LTE standard, will be the main object, but the main point of the present invention is to provide a communication system It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In the communication system in which a base station transmits a downlink signal to a mobile station and an uplink signal is transmitted from a mobile station to a base station in an embodiment of the present invention described below with reference to a mobile station connectable to an LTE system, Or perform direct communication between terminals using an uplink. The LTE downlink signal includes a data channel including information, a control channel for transmitting a control signal, and a reference signal (RS) for channel measurement and channel feedback of the UE. Also, the uplink signal of the LTE includes a data channel including information, a control channel for transmitting feedback information or a control signal, and a reference signal (SRS) for measuring a channel of the UE.

In the case of downlink, the LTE base station transmits data information and control information to the UE via a Physical Downlink Shared Channel (PDSCH) and a DL CCH (Downlink Control Channel).

In the case of the uplink, the data channel is transmitted through a physical uplink shared channel (PUSCH) and the control channel is transmitted through a physical uplink control channel (PUCCH).

The LTE base station may have a plurality of reference signals. The reference signal may include a common reference signal (CRS), a channel information signal (CSI-RS), a demodulation signal, (DMRS, demodulation reference signal).

The CRS is transmitted over the entire downlink band, and all terminals in the cell are used to demodulate and measure the channel. In order to reduce the resources used for CRS transmission, the BS transmits a dedicated terminal reference signal (DMRS) only to the UE in the scheduled area, and transmits the CSI-RS on the time and frequency axis for channel information acquisition.

The UE transmits a data channel (PUSCH) and a control channel (PUCCH) using a dedicated terminal reference signal (DMRS), and can transmit SRS (Sounding Reference Signal) for uplink channel measurement. SRS is transmitted to the last symbol of the uplink subframe, and PUSCH and PUCCH can not be transmitted simultaneously with SRS. The PUCCH is generally transmitted at the edge of the uplink bandwidth, and the PUSCH can be transmitted over the entire uplink band.

FIG. 1 shows a system for communication between terminals in a communication system for transmitting and receiving data between a base station and a terminal.

Referring to FIG. 1, the base stations 103 and 105 can communicate with the terminal 108, which supports communication in the base station coverage where the synchronization signals of the base stations 103 and 105 are transmitted (In-coverage). At this time, data to be transmitted to the terminal 108 is transmitted from the network 101 to the base stations 103 and 105, and the base stations 103 and 105 schedule the radio resources to the terminal 108 and transmit data to the terminal 108 (115).

However, if the base station 130 loses its coverage due to emergency or disaster situation, the terminal 109 can no longer locate the base station 130, and communication between the base station and the terminal becomes impossible. In this case, it is possible to support communication between the terminals 109 where the base station coverage does not exist (Out-coverage) through inter-terminal communication. In addition, it is possible to support communication between the terminals 108 in the coverage of the base station, as well as communication between the terminal 109 in which the base station coverage does not exist and the terminal 108 in which the coverage of the base station exists.

The communication described above is an inter-terminal communication, and an embodiment of the present invention is an example in which the terminal 108 receives data from the base stations 103 and 105 and the other terminals 108 in the base station coverage or the terminal 109 without the base station coverage And can be applied when supporting communication.

2 is a diagram illustrating a downlink sub-frame.

개의 심볼로 구성되어 있어 제어 채널과 데이터 채널, 기준 신호를 전송한다. Referring to FIG. 2, the scheduling unit of the base station is downlink subframes 201 and 203, one subframe 201 and 203 are composed of two slots 205,

And transmits a control channel, a data channel, and a reference signal.

개의 심볼 중, 시간적으로 빠른

개의 심볼(211)은 제어 채널(211)을 전송하는데 사용되며, 나머지 심볼인

개의 심볼은 데이터 채널(213)의 전송에 사용된다. In the sub-frame 201,

Of the symbols,

Symbols 211 are used to transmit the control channel 211, and the remaining symbols < RTI ID = 0.0 >

≪ / RTI > symbols are used for transmission of the data channel 213.

개의 부반송파 혹은 RE (resource element)로 구성되어 있다. 시간 축으로 2개의 슬롯과 하나의 RB단위를 PRB pair로 칭한다. PRB pair에는 CRS(Common reference signal, 209), CSI-RS(Channel state information Reference signal), DMRS(Demodulation RS, 207)가 전송된다.The transmission bandwidth consists of a resource group (RB, 217) on the frequency, and each RB (217)

Subcarriers or resource elements (REs). Two slots and one RB unit on the time axis are referred to as a PRB pair. A common reference signal (CRS) 209, a channel state information reference signal (CSI-RS), and a Demodulation RS 207 are transmitted to the PRB pair.

In order to measure a downlink channel, a base station transmits a CRS or a CSI-RS to allow the UE to perform channel measurement. When the UE reports a channel measurement result to the BS, the BS can recognize the downlink channel state between the BS and the UE .

The downlink subframe can be divided into a normal subframe 201 and a multimedia broadcast multicast service frequency network (MBSFN) subframe 203 according to its structural characteristics. In the MBSFN subframe, the first two symbols are transmitted in the same manner as the normal subframe, and no CRS is transmitted in the remaining symbols.

3 is a view showing an uplink sub-frame. Referring to FIG. 3, the uplink channel measurement is performed by instructing the BS to transmit the SRS 309 by the MS. Specifically, the base station can recognize the uplink channel (channel state) by receiving the SRS 309 transmitted by the terminal.

개의 심볼로 구성되어 있으며, 단말은 심볼을 통해 제어 채널, 데이터 채널(307), 기준신호(305) 등을 전송한다. The UE uses uplink subframes 301 and 302 as a basic time unit of uplink transmission and the uplink subframes 301 and 302 are composed of two slots. Each subframe has a total

And a terminal transmits a control channel, a data channel 307, a reference signal 305, and the like through a symbol.

The control channel (PUCCH) is transmitted on the edge in the frequency band in the uplink band 303, and one PUCCH is transmitted while alternating the uplink edges on a slot basis.

As shown in FIG. 3, the control channel and the data channel allocate a part of the allocated symbols to the reference signal (DMRS) 305 so that the base station can demodulate the signal transmitted by the terminal. The SRS is transmitted to the last symbol of the subframe 302, such as 309, at which time the data channel is not transmitted in the last symbol to which the SRS is transmitted.

Direct communication between terminals can support two kinds of communication. First, it means a transmission in which one terminal directly communicates with another terminal through a unicast transmission. Second, in a multicast or broadcast transmission, a terminal transmits a same data to an unspecified number of terminals it means. Examples of unicast transmission include transmission of voice data or data transmitted to a specific user such as a messenger. Examples of the multicast or broadcast transmission include communications transmitted to an unspecified number of users such as emergency information, advertisement, have.

Each terminal needs to recognize a neighboring terminal for direct communication between terminals, which can be known by receiving a discovery channel. A discovery channel is a signal that terminals transmit their information for direct communication between terminals. An arbitrary terminal can recognize hundreds or thousands of discovery channels, thereby recognizing a large number of terminals existing in the vicinity.

FIG. 4 illustrates a discovery channel region of an uplink radio frame applied in the present invention.

4, a resource 411 for a discovery channel can be transmitted to a sub-frame 405 or a slot 403 of a radio frame 401 of a downlink band or an uplink band 407 , And may be transmitted to the uplink 407 in the preferred embodiment. The subframe 405 in which the discovery channel 409 is transmitted has one or more discovery channels 409 and each terminal transmits a discovery channel to one or more resources 413 of the discovery channel resources.

The uplink band 407 is advantageous in that it can be multiplexed with another terminal because it is a band in which the terminal performs transmission. In the case of the downlink, there is a problem that transmission / reception may not be performed because the transmission of the terminal acts as an interference because the base station is transmitting. In addition, when the embodiment of the present invention is applied to a method of using a message, the terminal may transmit the discovery channel 413 in the same manner as other data channels in order to confirm the information of the discovery channel 413 The decoding operation must be performed.

5 is a diagram for explaining a method of managing a soft buffer for a data channel in an LTE system.

Referring to FIG. 5, the soft buffer is also referred to as soft bits, and refers to a memory or a buffer for storing a received data channel in the process of receiving a data channel or receiving a data channel. The terminal has a limited soft buffer size according to the capabilities of the terminal and is used to split the soft buffer and receive each data channel. In this case, the size of the soft buffer does not mean the total size of the physical memory of the terminal.

Generally, when a size of a soft buffer is set as 501, a soft buffer is allocated to a process of a DL data channel supported by a BS (hereinafter referred to as a 'Hybrid Automatic Retransmit Request (HARQ) process') Can be separated according to the number. If the UE has a total of 8 HARQ processes 505, the size of one soft buffer memory may be evenly divided for each HARQ process as 503. The size 501 of the total soft buffer actually needed can be generally calculated as: < EMI ID = 1.0 >

In contrast, when the total soft buffer size of the UE is determined, the size of the soft buffer for one HARQ process is given by Equation (2).

Referring to Equation (2), the UE divides the total size of a given soft buffer into a total number of downlink bandwidths that are used first, and divides each of them into a maximum HARQ process. If MIMO transmission is supported, MIMO can support up to two codewords. Therefore, the soft buffer size for one HARQ process is obtained by dividing by 2 times (Kmimo = 2) of the maximum HARQ process.

If the number of HARQ processes supported by the UEs is the same and the total number of supported HARQ processes is the same, the UEs with the smallest total soft buffer size and the UEs with the small total soft buffer size, Since the size of the soft buffer storing one HARQ process is small, the area where the UE can receive and store data is small. Therefore, there arises a problem that the minimum coding rate that can be supported by the terminal increases, and there arises a problem that coverage is reduced due to the limitation of the maximum distance of the supportable terminals due to such a phenomenon.

Therefore, if the terminal receives data from the base station, data from the terminal, and the discovery channel from the terminal with the same size of the soft buffer, the reception performance from the terminal is reduced. Therefore, management is important. Also, in the case of the discovery channel received from the terminal, since the number of channels to be received simultaneously changes continuously and it is difficult to predict the amount, the memory may remain or the efficiency may be deteriorated.

Table 1 is a table showing a possible maximum soft buffer size according to a category of a terminal in an LTE system. The terminal transmits the following category information when accessing the base station. If the terminal has additional functions other than the basic items included in each category information, additional information about the capability inherent to the terminal is transmitted along with the information shown in Table 1.

6 is a diagram for explaining a soft buffer management method for inter-terminal communication according to the first embodiment of the present invention.

According to the first embodiment described below, the terminal divides a memory or a buffer for a base station data channel into a plurality of areas, divides the divided memory or a part of the buffer area into a memory or buffer area for receiving the inter- . A part of the memory or buffer area for receiving the inter-terminal data channel is determined as a memory or buffer area for receiving the inter-terminal discovery channel.

Referring to FIG. 6, a mobile station first transmits a size (601) of its own total soft buffer to a base station along with a capability of a mobile station. The capability of the terminal also includes the capability for inter-terminal communication. The capability for inter-terminal communication means the capability of the terminal to receive and decode the discovery channel and the data channel of inter-terminal communication.

When the capability information for the inter-terminal communication is included as an option in an existing terminal category, the terminal can transmit information on whether the inter-terminal communication is supported while transmitting its category information to the base station. The BS can know the size of the soft buffer 601 of the MS based on the category information received from the MS and know whether the inter-MS communication is supported through the information on the received option.

Also, when a new category including information on inter-terminal communication is added to the existing terminal category, basic information of the category may include whether the terminal supports communication between terminals. Therefore, the terminal can transmit only the category information to the base station, and the base station can know the size information of the total soft buffer of the terminal corresponding to the category information and the capability information of the terminal by referring to the information stored in advance.

Table 2 below is a table showing a possible maximum soft buffer size according to the category of the UE in the LTE system according to the first embodiment of the present invention.

When the terminal accesses the base station, it transmits information as shown in Table 2 above. If there is an additional function for inter-device communication for each terminal, the terminal transmits additional information about the capability inherent to the terminal together with the information in Table 2. [ Here, the soft buffer size used for the data channel for inter-device communication is N (x), and the soft buffer size for the discovery channel is K (x), as shown in Table 2. The size of the soft buffer for each channel may be determined according to embodiments of the present invention. Where x is the category number.

Then, the UE is instructed by the Node B on the number of HARQ processes, which is the total number of downlink data channels that the UE should receive. The number of HARQ processes may be determined in a variety of ways including a method of determining the total number of combinations of the number of HARQ processes previously stored in the UE and the uplink signaling of the base station. Also, the base station transmits resources for inter-terminal communication to the terminal through higher signaling. The upper signaling for inter-terminal communication may include at least a total number of HARQ processes for inter-terminal data channels and resource allocation information for receiving a discovery channel.

The terminal receiving the information allocates its own soft buffer to each channel based on the given signaling. Specifically, the total soft buffer size 601 of the UE is divided according to the number of downlink HARQ processes 602 indicated by the BS. The space corresponding to some HARQ processes 603 may be determined to be used as an inter-terminal communication resource based on the number of HARQ processes 603 for the inter-user data channel in the information for inter-terminal communication transmitted by the base station in higher signaling have.

FIG. 6A shows an example in which there are eight HARQ processes (# 0 to # 7) receivable from the base station and nine resources 604 for inter-terminal communication. In the case of data received from the base station, three times the amount of data information is stored in the soft buffer in order to store the HARQ retransmission. Therefore, in the case of an inter-terminal data channel that does not support retransmission, It is possible to store the ship. Thus, a portion of the soft buffer space allocated for end-to-end communication may be used for resources 605 for the discovery channel 607 for end-to-end communication.

Equation (3) below shows a method of obtaining the size of a soft buffer for receiving an inter-user data channel according to the first embodiment of the present invention.

In an embodiment of the present invention, the soft buffer size for the discovery channel for inter-terminal communication is not fixed and may vary depending on the size of the discovery channel. If the possible size of the discovery channel is assumed to be 104 bits, the bit required for actual coding is 116 bits plus 12 bits, so 116 bits becomes the soft buffer size for one discovery channel. If one base station downlink data soft buffer size is assumed to be 10296, the terminal can decode and store a total of 266 discovery channels.

In order to effectively manage the memory, the terminal can allocate a soft buffer area for a data channel between terminals to a soft buffer area for a data channel received from the base station first.

Referring to FIG. 6 (b), if the resources used for the discovery channel decrease, the terminal may reduce the size of the area for receiving the discovery channel in the soft buffer area for receiving the data channel of the inter-terminal communication ( 615). As the size of the area for receiving the discovery channel is reduced, the area 614 that was originally allocated for receiving the discovery channel can be used as a resource for the inter-terminal data channel.

Similarly, the data channel received from the base station can be preferentially allocated to the soft buffer area for receiving the data channel of the inter-terminal communication. When the size of the soft buffer area necessary for receiving the data channel for inter-terminal communication decreases, the terminal uses the area 612 originally allocated for the data channel reception of the inter-terminal communication as a soft buffer for the data channel received from the base station .

According to the first embodiment of the present invention described above, the terminal can adjust the size of the soft buffer of the data channel for inter-terminal communication by reflecting the dynamic change of the amount of the discovery channel and can receive more data from the base station There is also an advantage in that the performance of the data channel can be maintained because it does not reduce the soft buffer size of other data channels as well.

As described above, in the first embodiment of the present invention, since the UE uses a part of the total HARQ process supported by the Node B for inter-UE communication, the total supported HARQ process can be reduced while receiving the inter-terminal communication channel. The second embodiment of the present invention described below is a method for minimizing such a phenomenon.

7 is a diagram for explaining a soft buffer management method for inter-terminal communication according to a second embodiment of the present invention.

In the second embodiment of the present invention, a terminal divides a soft buffer in consideration of a memory for a base station data channel or a memory or buffer for a data channel for communication between the buffer and the terminal, And determines a memory or buffer for receiving the inter-discovery channel.

Referring to FIG. 7, the mobile station first transmits the size 701 of its total soft buffer to the base station, together with the capability of the mobile station. The capability of the terminal also includes the capability for inter-terminal communication.

Since the memory space for the base station data channel and the memory space for the data channel of the inter-terminal communication are handled separately, the second embodiment of the present invention can be applied to the newly defined soft buffer size and inter- New categories may be added that contain information. Therefore, the terminal can transmit its category information to the base station, and the base station can know the size information of the total soft buffer of the terminal corresponding to the category information and the capability information of the terminal by referring to the previously stored information.

Table 3 below is a table showing a possible maximum soft buffer size according to the category of the UE in the LTE system according to the second embodiment of the present invention.

The terminal transmits the information in Table 3 when accessing the base station. In the case of the second embodiment of the present invention in which a terminal supporting communication between devices is configured with a new soft buffer size, a terminal category 9-12 may be added as shown in Table 3.

The new category uses a size of N (x) for the entire soft buffer size, which is always set larger than the soft buffer size used in the existing category.

Then, the UE is instructed by the Node B on the number of HARQ processes, which is the total number of downlink data channels that the UE should receive. The number of HARQ processes may be determined in a variety of ways including a method of determining the total number of combinations of the number of HARQ processes previously stored in the UE and the uplink signaling of the base station. Also, the base station transmits resources for inter-terminal communication to the terminal through higher signaling. The upper signaling for inter-terminal communication may include at least a total number of HARQ processes for inter-terminal data channels and resource allocation information for receiving a discovery channel.

The terminal receiving the information allocates its own soft buffer to each channel based on the given signaling. Specifically, the total soft buffer size 701 of the UE is preferentially allocated to the HARQ process for the downlink HARQ process 702 and the data channel of the inter-UE communication.

7A shows an example in which there are eight HARQ processes (# 1 to # 7) receivable from the base station and 12 resources 704 for inter-terminal communication. In the case of data received from the base station, three times the amount of data information is stored in the soft buffer in order to store the HARQ retransmission. Therefore, in the case of an inter-terminal data channel that does not support retransmission, It is possible to store the ship.

As shown in FIG. 7A, the second embodiment of the present invention allows a portion of the soft buffer allocated for inter-terminal communication to be used for resources 705 for the discovery channel 704 of inter- have.

Equation (4) below shows a method of obtaining the size of a soft buffer for receiving an inter-user data channel according to the second embodiment of the present invention.

As in the first embodiment of the present invention, the size of the soft buffer for the discovery channel for inter-terminal communication is not fixed, and may vary depending on the size of the discovery channel. If the possible size of the discovery channel is assumed to be 104 bits, the bit required for actual coding is 116 bits plus 12 bits, so 116 bits becomes the soft buffer size for one discovery channel. If one base station downlink data soft buffer size is assumed to be 10296, the terminal can decode and store a total of 266 discovery channels.

7, the terminal includes a soft buffer area 714 for receiving a data channel for inter-terminal communication in a soft buffer area 715 for reception of a discovery channel for effective memory management, Can be assigned as priority.

Accordingly, if the resource used for the discovery channel is reduced, the terminal may reduce the size of the area for receiving the discovery channel in the soft buffer area for receiving the data channel of the inter-terminal communication (715). By reducing the size of the area for receiving the discovery channel, the area 716 that was originally allocated for receiving the discovery channel can be used as a resource for the inter-terminal data channel.

According to the second embodiment of the present invention described above, the terminal can adjust the size of the soft buffer of the data channel for the inter-terminal communication by reflecting the dynamically decreasing amount of the discovery channel, and at the same time, There is an advantage that base station data can be received in the same manner as in the case of not transmitting the base station data.

If the size of the total soft buffer is the same as that of the first embodiment, the performance of the data channel received from the base station may decrease in the second embodiment. However, in the second embodiment, the size of the total soft buffer in the case where the terminal supports communication between terminals is larger than that of a terminal that does not support inter-terminal communication. Therefore, the inter-terminal communication does not affect the communication from the base station.

FIG. 8 illustrates an operation of a base station according to an embodiment of the present invention.

Referring to FIG. 8, in step 801, the base station receives the size of the total soft buffer of the terminal from the terminal together with the capability of the terminal. As described above, the information received from the terminal can be received as category information of the terminal.

In step 803, the BS indicates to the MS the number of HARQ processes, which is the total number of downlink data channels that the MS should receive from the BS. The number of HARQ processes to be indicated may be determined in various ways including a method of determining the total number of HARQ processes stored in the UE in combination with the upper signaling of the BS. The base station also transmits information for inter-terminal communication including the soft buffer size for inter-terminal communication and the configuration information of inter-terminal communication to the terminal. Thereafter, the base station does not participate in the inter-terminal communication and schedules and transmits the data transmitted from the base station to the terminal, as shown in step 805.

FIG. 9 illustrates operations of a terminal according to an embodiment of the present invention.

Referring to FIG. 9, in step 901, the terminal forwards the size and capability information of its total soft buffer to the base station. As described above, the category information of the terminal includes information on various capabilities of the terminal, including the total soft buffer size.

Then, in step 903, the terminal receives information for inter-terminal communication together with information on a data channel received from the base station through higher signaling from the base station. Specifically, the information transmitted to the upper signaling includes a number of HARQ processes, which is the total number of downlink data channels that the mobile station should receive from the base station, a soft buffer size for communication between the mobile stations, Information for inter-communication can be included.

In step 905, the terminal divides the size of its soft buffer based on the information received in step 903. The first embodiment and the second embodiment of the present invention described above can be applied to the division of the soft buffer. In step 907, the terminal receives a discovery channel from another terminal for inter-terminal communication, and then receives a data channel for inter-terminal communication. Finally, in step 909, the terminal decodes the received data channel for the discovery channel and the inter-terminal communication, and temporarily stores the data channel in the divided soft buffer in step 905.

10 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 10, the terminal controller 1011 controls the receiving apparatus 1001 and the transmitting apparatus 1003 by using the duplexer 1005. And also controls the data channel receiver 1007 and the discovery channel receiver 1009 to receive a discovery signal and a data channel for inter-terminal communication, and stores the received information in the memory 1015. A memory for storing information, In order to transmit a discovery channel and a data channel for inter-terminal communication, the controller 1011 notifies another terminal of its existence through a discovery signal transmitter 1013, Generates a data channel between terminals through the data channel transmitter 1017 and transmits the information.

11 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention.

11, the base station may include a wireless transceiver 1110, a controller 1120, and a storage unit 1130. The scheduler 1125 may be provided inside or outside the controller 1120, And performs scheduling for transmitting the data channel to the UE according to the control of the scheduler 1120.

The control unit 1120 receives the total soft buffer size and the capability information of the UE from the UE through the wireless transceiver 1110 and generates HARQ, which is the total number of downlink data channels that the UE should receive from the BS, The number of processes, the size of the soft buffer for communication between the terminals, and the configuration information of the inter-terminal communication, and transmits the determined information to the terminal. In addition, the storage unit 1130 may store information necessary for the BS to perform the embodiment of the present invention, for example, specific information included in the category information of the UE.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalents thereof are included in the scope of the present invention Should be interpreted.

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 embodiments, but, on the contrary, And is not intended to limit the scope of the invention. It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (20)

A soft buffer management method of a terminal for inter-device communication in a wireless communication system,
Transmitting the terminal information including the size of the soft buffer and whether or not the inter-device communication is supported to the base station;
Receiving control information generated based on the terminal information from the base station; And
And dividing the soft buffer based on the control information. The method according to claim 1,
Wherein dividing the soft buffer comprises:
Dividing the entire area of the soft buffer into a plurality of areas corresponding to the number of Hybrid Automatic Retransmission Request (HARQ) processes included in the control information;
Determining an area for receiving the data channel of the inter-device communication among the plurality of areas; And
And determining an area for receiving a discovery channel of the inter-device communication from an area for receiving the data channel of the inter-device communication. The method according to claim 1,
Wherein dividing the soft buffer comprises:
Dividing an entire area of the soft buffer into an area for receiving a downlink data channel and an area for communication between the terminals;
Dividing an area for receiving the downlink data channel into a plurality of areas corresponding to the number of Hybrid Automatic Retransmission Request (HARQ) processes included in the control information;
Determining an area for receiving the discovery channel of the inter-device communication among the areas for inter-terminal communication, and determining the remaining area as an area for receiving the data channel of the inter-terminal communication; Way. The method according to claim 1,
Wherein the transmitting of the terminal information comprises transmitting information on the category information of the terminal and information on whether or not the communication between the devices is supported. The method according to claim 1,
Wherein the step of transmitting the terminal information comprises transmitting the category information of the terminal including information on whether or not the inter-device communication is supported. The method according to claim 1,
Wherein the control information includes Hybrid Automatic Retransmission Request (HARQ) setting information and configuration information of the inter-device communication. The method according to claim 1,
Receiving a downlink channel of the base station according to the scheduling information received from the base station and receiving a channel of the inter-terminal communication. A method of providing information of a base station for soft buffer management of a terminal in a wireless communication system,
Receiving terminal information including a size of the soft buffer of the terminal and whether or not the inter-device communication is supported from the terminal;
Transmitting control information generated based on the terminal information to the terminal; And
And transmitting scheduling information for transmitting downlink data to the mobile station. 9. The method of claim 8,
Wherein the control information includes Hybrid Automatic Retransmission Request (HARQ) setting information and the device-to-device communication setting information. 9. The method of claim 8,
Wherein the terminal information is obtained from category information received from the terminal. A terminal for managing soft buffers for communication between devices in a wireless communication system,
A transmitting and receiving unit transmitting and receiving signals to and from a base station and a terminal supporting communication between the apparatuses; And
The base station transmits terminal information including the size of the soft buffer and support for inter-device communication to the base station, receives control information generated based on the terminal information from the base station, And a controller for dividing the buffer. 12. The method of claim 11,
The control unit may be configured to divide the soft buffer,
Dividing the entire area of the soft buffer into a plurality of areas corresponding to the number of Hybrid Automatic Retransmission Request (HARQ) processes included in the control information,
Determining an area for receiving the data channel of the inter-device communication among the plurality of areas,
And determines an area for receiving the discovery channel of the inter-device communication among the areas for receiving the data channel of the inter-device communication. 12. The method of claim 11,
The control unit may be configured to divide the soft buffer,
The entire area of the soft buffer is divided into an area for receiving a downlink data channel and an area for communication between the terminals,
Dividing an area for receiving the downlink data channel into a plurality of areas corresponding to the number of Hybrid Automatic Retransmission Request (HARQ) processes included in the control information,
Determines an area for receiving the discovery channel of the inter-device communication among the areas for inter-terminal communication, and determines the remaining area as an area for receiving the data channel of the inter-terminal communication. 12. The method of claim 11,
Wherein the control unit transmits, as the terminal information, information on the category of the terminal and information on whether or not to support the communication between the apparatuses. 12. The method of claim 11,
Wherein the control unit transmits category information of the terminal including information on whether or not the inter-device communication is supported as the terminal information. 12. The method of claim 11,
Wherein the control information includes Hybrid Automatic Retransmission Request (HARQ) configuration information and configuration information of the inter-device communication. 12. The method of claim 11,
Wherein the controller receives the downlink channel of the base station according to the scheduling information received from the base station and receives the channel of the inter-terminal communication. A base station for providing information for soft buffer management of a terminal in a wireless communication system,
A wireless transceiver for transmitting and receiving signals to and from the terminal; And
Receiving the terminal information including the size of the soft buffer of the terminal and the support of inter-device communication from the terminal, transmitting the control information generated based on the terminal information to the terminal, and transmitting the downlink data to the terminal And a control unit for transmitting scheduling information for transmission. 19. The method of claim 18,
Wherein the control information includes Hybrid Automatic Retransmission Request (HARQ) configuration information and configuration information of the inter-device communication. 19. The method of claim 18,
And the terminal information is obtained from the category information received from the terminal.

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