KR20150143135A - Method and apparatus for transmitting and receiving resource allocation information in wireless mobile communication system - Google Patents

Abstract

As various services are newly developed in a wireless cellular communications system, the need for peer to peer (P2P) communications is increased. When P2P communications are used in the cellular communications system, an existing terminal using cellular communications and a terminal using P2P communications exist at the same time, and thus subsequent problems occur. The terminal using P2P communications which has a single reception chain has a disadvantage of not receiving a downlink cellular signal and a P2P communications signal at the same time. Moreover such terminal using P2P communications has problems that the terminal can′t synchronize to a base station or P2P communications performance deterioration can be generated, when a resource region for P2P communications is overlapped with a downlink or a paging signal on time. The present invention provides a method to allocate the resource region for P2P communications so that an important signal and a channel of a downlink is not overlapped on time. The present invention provides a method for the terminal to receive the signal efficiently when the important signal of the downlink and the resource region for P2P communications are overlapped on time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for transmitting and receiving resource allocation information in a wireless mobile communication system,

The present invention relates to a method and an apparatus for transmitting / receiving resource allocation information in a wireless mobile communication system.

As the types of services using the wireless mobile communication system have become various, there is a need for a new technology to more efficiently support new emerging services. Accordingly, new methods and new technologies in wireless mobile communication systems have been developed and studied.

Device-to-device (D2D) communication is a new technology that emerged as a solution to a new service. Basically, it represents a technology that allows an arbitrary terminal to directly communicate with another terminal existing around the terminal. When the D2D communication technology is used, the terminal discovers which terminals exist around the terminal and can perform direct communication with a terminal requiring communication.

When direct communication is performed between the UE and the UE, a relatively small amount of radio resources is used in comparison with the case of performing communication using a base station using an existing wireless network. Therefore, when D2D communication is used, it has a great advantage in radio resource efficiency. In D2D communication, since a method of discovering a terminal around the terminal is supported, the terminal can directly provide necessary information to a desired terminal, thereby supporting an advertisement service, a social networking service (SNS) The efficiency can be greatly increased.

Currently, long term evolution-advanced (LTE-A) systems also require support for D2D technology, and technical discussions are under way.

1 is a diagram illustrating a wireless mobile communication system in which D2D communication is performed.

Referring to FIG. 1, a base station 101 manages a terminal 103 and a terminal 104 in a cell 102 managed by the base station 101. The terminal 103 performs cellular communication using the link 106 between the base station 101 and the terminal-base station 104 and the terminal 104 transmits the link 107 between the base station 101 and the terminal- To perform cellular communication. The D2D communication between the terminal 103 and the terminal 104 can directly transmit and receive information using the D2D link 105 without passing through the base station 101. [ The two terminals 103 and 104 can perform discovery and communication using the D2D link 105. [

It is assumed that the D2D technology using a wireless mobile communication system such as the LTE-A system is basically executed so as not to damage the terminal using the existing cellular system as much as possible. For this purpose, a radio resource used by the cellular terminal (in this specification, the cellular terminal indicates a terminal performing existing terminal-to-base station communication rather than D2D communication) and a resource that does not overlap with each other may be used for D2D communication, It is also possible to consider using the same resources as the resources used by the D2D terminal but not interfering with each other as much as possible.

A wireless mobile communication system in which cellular communication is performed may provide two connections for bidirectional communication between a base station and a terminal. The wireless mobile communication system includes an uplink for transmitting data to a base station in a cell and a downlink for transmitting data to a specific terminal or an unspecified number of terminals in the cell. There is a frequency division duplexing (FDD) method in an uplink and downlink duplexing method used in an LTE or LTE-A system.

In the system using the FDD (hereinafter, referred to as 'FDD system'), different frequency resources are used to distinguish the uplink from the downlink. When the D2D communication is used differently from the existing cellular communication resources in the FDD system, a method of using uplink frequency resources for uplink and downlink frequency resources for D2D communication tends to be a higher priority in general. This is because, in the FDD system, more types of signals are multiplexed in the downlink frequency resource than in the uplink frequency resource, and it is difficult to allocate resources separately for the purpose of D2D communication compared to the uplink frequency resource.

Also, in an FDD system considering only existing cellular terminals, downlink traffic tends to be higher than uplink traffic due to the characteristics of communication service, and overhead transmitted in downlink is higher than that of uplink, The usage burden on the uplink frequency resource is generally larger than the usage burden on the uplink frequency resource. Therefore, if the downlink frequency resource is allocated for use for D2D communication, the burden on the downlink frequency resource becomes greater, and it becomes difficult to balance the use of the uplink and downlink frequency resources.

Assuming that the FDD system performs D2D communication using the uplink frequency resource, the problem caused by using the downlink frequency resource in the D2D technique described above can be solved. However, applying the D2D communication technique using the uplink frequency resource does not solve all the problems.

In a wireless mobile communication system in which cellular communication is performed, a mobile station must receive a downlink signal at predetermined time intervals in order to receive synchronization and control information with a base station. In the LTE or LTE-A system, the terminal is said to be in the idle state (RRC_Idle) state.

In order for the terminal to request downlink data reception and uplink data transmission to the base station, the terminal must perform uplink synchronization by performing a random access procedure with the base station. Then, the terminal can perform data transmission / reception with the base station. The UE is referred to as a RRC_Connected state with the BS.

The D2D terminal can start the D2D communication by obtaining the resource allocation information for the D2D communication from the base station. The base station can transmit resource allocation information for D2D communication through a downlink physical channel or upper signaling transmitted in a downlink. Therefore, the D2D terminal must be able to perform downlink synchronization with the base station and acquire resource allocation information for D2D communication regardless of the idle state or the connection state of the base station. In addition, the D2D terminal must periodically receive a downlink signal through which resource allocation information for D2D communication is transmitted to check whether the resource allocation information for D2D communication is changed. At the same time, the D2D terminal must be able to transmit a signal for D2D direct communication or terminal discovery in an uplink resource area determined based on resource allocation information for D2D communication, or receive a D2D signal transmitted by a nearby D2D terminal.

2 is a diagram illustrating a receiver structure of a D2D terminal having two radio frequency (RF) reception chains.

2, the D2D terminal includes a receiver 200 and an antenna 201. The receiver 200 includes an RF tuner 202 for receiving a cellular downlink signal, a D2D An RF tuner 203 for receiving signals, a cellular downlink baseband receiver 204 and a D2D baseband receiver 205. The radio signal is transmitted to the two RF tuners 202 and 203 via the antenna 201. The RF tuner 202 for receiving the cellular downlink signal separates the cellular downlink signal into a baseband signal, and then transmits the baseband signal to the cellular downlink baseband receiver 204. The RF tuner 203 for receiving the D2D signal demultiplexes the D2D signal into a baseband signal, and then transmits the baseband signal to the D2D baseband receiver 205. [

Since the D2D terminal of FIG. 2 is separated from the cellular downlink and the RF tuner capable of receiving the D2D signal, the D2D terminal simultaneously transmits the D2D direct communication signal and the terminal discovery signal transmitted by the neighboring D2D terminal and the cellular downlink signal at the same time There is an advantage to receive. However, since the above-mentioned D2D terminal includes two RF reception chains, the cost is increased.

3 shows a receiver structure of a D2D terminal having a single RF receive chain.

3, the D2D terminal includes a receiver 300 and an antenna 301. The receiver 300 includes an RF tuner 302, a cellular downlink baseband receiver 303 and a D2D baseband receiver 304). The RF tuner 302 can separate the D2D signal transmitted in the uplink and the cellular downlink signal according to the setting of the D2D terminal, but can not convert the two signals simultaneously. Therefore, the D2D terminal can not simultaneously receive the cellular downlink signal and the D2D signal.

As shown in FIG. 3, in the D2D terminal having a single RF reception chain, a control and synchronization signal transmitted through the cellular downlink and a D2D signal transmitted from the surrounding D2D terminal can not be simultaneously received on the time axis.

For example, the D2D terminal must receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) transmitted in downlink for synchronization with a base station. If the D2D terminal must receive the uplink sub-frame including the D2D signal at the same time as the transmission time of the PSS and the SSS, i.e., the downlink sub-frame including the synchronization signal, the D2D terminal transmits a single RF reception Frame, one of the downlink subframe and the uplink subframe must be received. At this time, if the D2D terminal does not receive the downlink subframe including the synchronization signal, the D2D terminal loses synchronization with the base station, and cellular communication becomes impossible. On the other hand, when the D2D terminal receives the DL sub-frame including the synchronization signal, the D2D terminal may miss the information transmitted by the surrounding D2D terminal.

As another example, the D2D terminal should receive base station control information transmitted in a cellular downlink and use it for cellular communication. The base station control information also includes resource allocation information for D2D communication. Therefore, the D2D terminal must always receive the base station control information transmitted by the base station for the cellular communication and the D2D communication. If the cellular control information signal and the D2D signal transmitted through the downlink are transmitted at the same time, the corresponding D2D terminal can receive only one of the two signals even if the frequency resources are different. If the D2D terminal receives the D2D signal, it can not receive the control information transmitted by the base station. Therefore, it is impossible to track the change of the D2D resource allocation information as well as the cellular communication, so that the D2D communication becomes impossible.

In D2D technology of LTE-A (specifically Release-12 compliant LTE-A), a D2D terminal for direct communication supporting public safety network transmits a D2D signal using a downlink cellular signal and an uplink It is assumed that the receiver structure is capable of receiving simultaneously. On the other hand, a D2D terminal (for example, a D2D terminal for terminal discovery or a D2D terminal for commercial direct communication), which is not a direct communication for the public safety network, must receive the D2D signal using the downlink cellular signal and the uplink at the same time It is assumed that there is no need to structure.

Therefore, since all of the D2D terminals may not include both the communication and the discovery functions, the D2D terminal specialized for the discovery function may experience a problem according to the single RF reception chain structure described above.

As described above, when a control signal and a data signal are received from a base station via a cellular downlink and a D2D signal is received from a surrounding terminal through an uplink at the same time, a D2D terminal having a single receiver structure transmits a cellular downlink signal The D2D signal can not be received at the same time.

Accordingly, the present invention provides a D2D resource allocation method and a terminal reception method of a base station for solving the problem of a D2D terminal having a single receiver.

In order to achieve the above object, there is provided a resource allocation method for D2D in a wireless communication system of the present invention, comprising: allocating a D2D resource region such that a resource region and a synchronization signal for D2D communication do not overlap in time; And a method of efficiently receiving two signals when the resource area and the synchronization signal overlap in time.

In addition, in a wireless communication system of the present invention, a method of allocating a D2D resource region for a D2D communication and a base station allocating a D2D resource region so that a paging information of an idle D2D terminal is not overlapped or minimized And a control unit.

In addition, in the wireless communication system of the present invention, as a resource allocation method for D2D, a signal for a resource region for D2D communication, a signal for a multimedia broadcast and multicast service (MBMS), a signal for channel state information estimation (CSI-RS) and a hybrid automatic request (HARQ) are superimposed on a channel state information-reference signal (CSI-RS) .

A method according to an embodiment of the present invention comprises: A method of transmitting resource allocation information of a base station in a wireless mobile communication system, the method comprising: generating resource allocation information for device-to-device (D2D) communication of a terminal including a single receiver; Wherein the resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes at least one uplink subframe, And a position on the time axis is different from that of at least one downlink subframe used by the base station to transmit control information.

Another method according to an embodiment of the present invention comprises: A method of receiving resource allocation information of a terminal including a single receiver in a wireless mobile communication system, the method comprising: receiving resource allocation information for device-to-device (D2D) communication from a base station; Wherein the resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink The subframe is different in position on the time axis from the at least one downlink subframe used by the base station to transmit the control information.

Another method according to an embodiment of the present invention comprises: A method for receiving a subframe in a terminal including a single receiver in a wireless mobile communication system, the method comprising the steps of: determining whether a downlink subframe including control information and an uplink subframe including a D2D signal should be received at the same time; And receiving the downlink sub-frame preferentially when it is necessary to receive at the same time, wherein the control information includes ACK or NACK information, a multimedia broadcast / multicast service (MBMS) And a channel state information-reference signal (CSI-RS).

An apparatus according to an embodiment of the present invention includes: A base station in a wireless mobile communication system, comprising: a controller for generating resource allocation information for terminal-to-device (D2D) communication of a terminal including a single receiver; Wherein the resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the at least one uplink subframe, And the position on the time axis is different from that of at least one downlink subframe used for transmission.

Another apparatus according to an embodiment of the present invention includes: A terminal in a wireless mobile communication system, comprising: a single receiver for receiving resource allocation information for device-to-device (D2D) communication from a base station; and a base station for performing D2D communication based on the resource allocation information Wherein the resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the uplink subframe, And the position on the time axis is different from that of at least one downlink subframe used for transmission.

Another apparatus according to an embodiment of the present invention includes: A mobile station in a wireless mobile communication system, comprising: a controller for determining whether a downlink subframe including control information and an uplink subframe including a D2D signal should be received at the same time; And a single receiver for preferentially receiving a downlink subframe, wherein the control information includes ACK or NACK information, a multimedia broadcast / multicast service (MBMS) signal, and a channel state information -reference signal: CSI-RS).

According to an embodiment of the present invention, in a D2D terminal having a single RF receive chain, a D2D signal transmitted by a neighboring D2D terminal using a downlink signal for downlink synchronization, control information acquisition, or base station data reception, It is possible to prevent a situation in which the data is superimposed on the data. Still another embodiment of the present invention can provide an operation of the terminal that can minimize the influence on the D2D communication without affecting the cellular communication on the same problem.

1 is a diagram illustrating a wireless mobile communication system in which D2D communication is performed,
2 shows a receiver structure of a D2D terminal having two radio frequency (RF) receive chains,
3 shows a receiver structure of a D2D terminal with a single RF receive chain,
4 is a diagram illustrating a basic resource structure used for uplink and downlink resource allocation in a wireless mobile communication system in which cellular communication is performed;
5 is a diagram illustrating an example of a method of allocating resources for UE discovery based on an uplink frequency resource structure;
6 is a diagram for explaining a main parameter used for uplink resource allocation for terminal discovery in D2D communication,
7 is a diagram illustrating an example of uplink resource allocation for D2D communication according to an embodiment of the present invention.
8 is a flowchart showing a reception operation of a D2D terminal when the uplink D2D resources of a D2D terminal having a single RF receive chain and the subframe timing of a downlink PSS / SSS are overlapped, according to an embodiment of the present invention.
9 is a block diagram illustrating an internal structure of a base station that performs D2D communication resource allocation according to an embodiment of the present invention.
10 is a block diagram illustrating an internal structure of a UE having a single RF receive chain capable of receiving D2D reception and a downlink cellular signal 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.

Further, in describing embodiments of the present invention, a wireless communication system based on orthogonal frequency division multiplexing (OFDM) technology, particularly a 3GPP EUTRA standard, will be the main object, Other communication systems having similar technical backgrounds and channel types are also possible with minor modifications within the scope of the present invention, without departing from the scope of the present invention, which can be done by a person skilled in the art .

The present invention relates to a method and apparatus for receiving a wireless cellular communication signal and a terminal-to-terminal communication signal from a terminal having a single reception chain in a state where a device-to-device (D2D) communication technology and a wireless- Terminal-to-terminal communication resource allocation method, terminal receiving method, and apparatus thereof.

In the embodiment of the present invention described below, a base station or a cell can be used in the same sense. Also, in the embodiment of the present invention, a terminal discovery operation for searching for a terminal adjacent to the D2D communication is mainly described. However, the D2D communication includes both direct communication in which the terminal and the terminal directly communicate information Can be used as a meaning. In the embodiment of the present invention, it is assumed that D2D communication is performed using uplink frequency resources in a system using frequency division duplexing (FDD) as a duplexing method.

4 is a diagram illustrating a basic resource structure used for uplink and downlink resource allocation in a wireless mobile communication system in which cellular communication is performed.

Referring to FIG. 4, uplink and downlink are divided into different frequency resources on the frequency axis. The uplink and downlink include a plurality of frames, and one frame 401 has a time interval of 10 ms on the time axis. One frame 401 includes a plurality of subframes 402 and 403. The subframe is, for example, a 1 ms time interval including a plurality of symbols as a time unit used in the LTE communication system. In FIG. 4, the subframe used in the LTE communication system has been described as an example of a time unit. However, in the embodiment of the present invention, the time unit is not limited thereto and any time unit may be applied.

One downlink subframe 402 includes a plurality of OFDM symbols on a time axis and one uplink subframe 403 includes a plurality of single carrier-frequency division multiplexing SC-FDM) symbols.

The base station constructs various data and control channels on a subframe-by-subframe basis, and transmits the data and control channels to a specific terminal and a terminal group on the downlink. The data and control channels may be mapped to a resource element or a resource block that is divided into time and frequency of a specific subframe and transmitted. The mapping of the data and the control channel may be repeated in units of a frame 401.

For example, in a LTE communication system, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) transmitted for cell search, time and frequency synchronization are transmitted in the 0th subframe The fifth OFDM symbol and the sixth OFDM symbol are used. Therefore, a UE that performs cell search and time and frequency synchronization with a base station in a cell must receive PSS and SSS in the 0th and 5th subframes of the frame. In addition, a UE in an idle state must receive a necessary information by receiving a subframe including a downlink broadcast channel and a paging channel.

A terminal in a cell transmits data and a control signal to a base station through a resource region allocated by a base station in an uplink. Data and control channel transmitted by the terminal to the base station are mapped to resource elements or resource blocks classified by time and frequency of a specific subframe and transmitted.

In the wireless mobile communication system using FDD as described above, D2D communication is performed using uplink resources. Therefore, a resource region for D2D communication can also be allocated in units of uplink subframes.

5 is a diagram illustrating an example of a method of allocating resources for UE discovery based on an uplink frequency resource structure.

In FIG. 5, for example, it is assumed that a part of the set 501 of uplink subframes is used as a resource for D2D communication, based on the format of uplink resources supported by the LTE communication system. Referring to FIG. 5, regular subframes 502 are allocated for cellular communication and D2D subframes 503 are allocated for D2D communication.

Specifically, the D2D subframes 503 may include a plurality of subframes in the uplink resource for the D2D communication. The uplink resources for D2D communication may be composed of a set of consecutive subframes as shown in FIG. 5, but may also be a set of non-consecutive subframes to which subframes for cellular communication are allocated within a predetermined interval .

In the uplink resources of the LTE communication system, among the subcarriers available in the frequency axis, a plurality of subcarriers located at both ends 504 and 505 of the frequency axis are allocated to an uplink control physical channel (for example, And a physical uplink control channel (PUCCH)). The uplink control physical channel includes forward link channel quality information (CQI) of the UE, ACK / NACK information as response information for a hybrid automatic repeat request (HARQ) technique of downlink communication, And scheduling request information for the scheduling request.

On the other hand, D2D transmission is possible through a plurality of subcarriers 506 located in the middle of the frequency axis excluding both ends of the subframe. At this time, the last OFDM symbol (or SC-FDM symbol) located in each subframe can be used for transmission of a sounding reference signal (SRS) required for uplink channel estimation of UEs in the base station. Since the period of transmission of the SRS varies depending on the setting of the base station, there may be a sub-frame including the SRS and a sub-frame not including the SRS. In the subframe not including the SRS, the last symbol 507 can be used as a resource for D2D communication. In addition, due to the characteristics of D2D communication, a terminal needs to continuously transmit and receive. In this case, consideration is given to a transition time required when changing operations from transmission to reception or from reception to transmission. The last symbol 507 may be used.

6 is a diagram for explaining a main parameter used for uplink resource allocation for terminal discovery in D2D communication.

The uplink resource allocation for D2D communication can be determined by the base station and informed to the D2D terminal through high-level signaling, or a predetermined resource can be used as the uplink resource for the D2D communication. The uplink resource information may be used by the D2D terminal to transmit the D2D discovery signal or to receive the D2D discovery signal transmitted by the neighboring terminal.

Referring to FIG. 6, uplink resource allocation for D2D communication may include resource period 601, size 602, and bitmap 603. The resource period 601 may indicate a time interval during which the D2D resource is repeatedly allocated. The size 602 of the resource indicates the size of the subframe 604 allocated for D2D communication. The subframe 604 allocated for D2D communication may be allocated consecutively within a given size, or may be allocated to non-consecutive subframes including subframes for cellular communication. The bitmap 603 may be used to indicate that a subframe corresponding to each bit of the bitmap 603 is a subframe allocated to the D2D, in contrast to the case where the D2D resource is composed of non-contiguous D2D subframes.

For example, when the first bit b0 and the second bit b1 of the bitmap 603 are '1' and '0', respectively, the D2D terminal allocates the first subframe allocated to the D2D resource to the D2D communication Frame, and that the second subframe can be used for cellular uplink communication. Also, the D2D subframe and the cellular uplink subframe can be distinguished by an opposite bit value. That is, when the first bit (b0) is '0' and the second bit (b1) is '1', the D2D terminal can use the first subframe assigned to the D2D resource as a subframe for D2D communication And that the second subframe can be used for cellular uplink communication.

Through the resource and resource allocation method for the D2D communication described above, the D2D terminal having a single RF receive chain as shown in FIG. 3 must receive the base station signal from the downlink in the subframe and transmit the D2D The D2D terminal can not receive the two signals at the same time. Therefore, a D2D resource allocation method of a base station and a signal reception method of a terminal for a D2D terminal having a single receiver according to various embodiments of the present invention will be described below.

First Embodiment: Timing Overlap of Synchronization Signal and D2D Resource Area

As described above, the UE must perform cell search, time synchronization, and frequency synchronization using the PSS and the SSS transmitted from the base station. For example, in a LTE communication system, a base station transmits a PSS and an SSS using a fifth OFDM symbol and a sixth OFDM symbol in the 0 < th > subframe and the 5 < th > subframe of a radio frame, respectively.

All terminals including the D2D terminal must always receive PSS and SSS for synchronization with the base station. The UE in the initial access stage must receive PSS and SSS for cell search, time and frequency synchronization required for initial synchronization. In case of a terminal already connected to the base station, it can periodically receive the PSS and the SSS for the purpose of handover due to movement of the terminal and synchronization tracking due to the influence of the change of the radio channel environment.

When the D2D resource region allocated to transmit / receive the D2D signal is composed of a plurality of subframes as described above with reference to FIG. 5, the subframe transmitting the D2D resource region allocated to the uplink and the downlink PSS and SSS is time Axis. In this case, a terminal having a single RF receive chain must either abandon D2D reception or relinquish base station synchronization.

As one embodiment for solving the above-mentioned problem, the base station may allocate the D2D resource region so as not to overlap the transmission time of the downlink subframe including the PSS and the SSS. For example, in the LTE communication system, the base station can exclude the 0th subframe and the 5th subframe of the uplink from the D2D resources.

7 is a diagram illustrating an example of uplink resource allocation for D2D communication according to an embodiment of the present invention.

Referring to FIG. 7, it is assumed that a size of uplink resource allocation for D2D communication has a time interval corresponding to one frame 701 in the embodiment of the present invention. That is, it is assumed that a total of 10 subframes 702 from the 0th subframe (SF # 0) to the 9th subframe (SF # 9) of the uplink are allocated for D2D communication. The 0th subframe (SF # 0) 703 and the 5th subframe (SF # 5) 704 of the downlink are used for transmitting PSS and SSS. The D2D terminal having a single RF receive chain can not receive the downlink subframe 703 and the uplink subframe 705 at the same time. In order to solve such a problem, in the embodiment of the present invention, as illustrated in FIG. 7, the base station transmits uplink sub-frames 705 corresponding to the same time as the sub-frames 703 and 704 including PSS and SSS in the downlink , 706) may be excluded from the D2D resource area.

When the BS excludes the uplink subframe corresponding to the transmission timing of the PSS and the SSS from the D2D resource region for the UE having a single RF reception chain, the BS transmits the D2D resource allocation information including the corresponding information to the D2D terminal Lt; / RTI >

The following two methods can be used as a method for informing the UE whether the 0th subframe 705 and the 5th subframe 706 of the uplink are included in the D2D resource area allocation.

As a first method among the above two methods, a base station uses a bitmap used for D2D resource allocation.

As described above with reference to FIG. 6, the base station can use the size, period, and bitmap of D2D resources for D2D resource allocation. The bitmap used for D2D resource allocation is considered to indicate a resource for uplink cellular communication when there is cellular data that a specific terminal in a cell must transmit within a subframe corresponding to the D2D resource size. By using the bit map, the base station designates the 0th and 5th subframes 705 and 706 among the subframes corresponding to the D2D resource size as a specific bit value (for example, '0'), Can accurately inform the D2D resource area. This method has an advantage that the existing bitmap can be maintained as it is, and the base station has an advantage that there is a degree of freedom in D2D resource allocation.

As a second method among the above two methods, there is a method of including 1-bit information indicating whether PSS and SSS are excluded in D2D resource allocation in D2D resource allocation information.

The base station may add 1 bit in addition to size, period, and bitmap to the existing D2D resource allocation information. The 1 bit indicates a bit (PSS / SSS excluded bit) indicating whether to collectively exclude uplink subframes corresponding to transmission timings of the PSS and the SSS in the D2D resource region allocated by the base station. The PSS / SSS excluded bit may be transmitted to the D2D terminal through higher-level signaling like other D2D resource allocation information.

As an example of using the PSS / SSS excluded bit, the base station sets the value of the PSS / SSS excluded bit to '0', and transmits the sub-frame overlapped with the downlink sub-frame including PSS and SSS in the uplink D2D resource region. Can be informed to the D2D terminal. When the value of the PSS / SSS excluded bit included in the D2D resource area allocation information is '0', the D2D terminal abandons D2D at the timing of the corresponding subframe, receives the downlink subframe including the PSS / SSS, And synchronize with each other.

As another method for solving the problem related to the overlapping of the downlink PSS / SSS reception and the D2D reception timing of the D2D terminal having the single RF reception chain as described above, the base station transmits the timing of the downlink subframe including the PSS and the SSS (In the above-described method, all the bitmaps are allocated to the D2D resource region or the D2D resource region is allocated to the D2D resource region through the PSS / SSS excluded bit, The D2D UE having a single RF receive chain can transmit the subframe including the PSS and the SSS and the downlink subframe including the predetermined number of PSS and SSS when the D2D resource region is overlapped on the time axis. And can receive the D2D signal received on the uplink. The MS may not perform base station synchronization using the PSS and the SSS while maintaining synchronization with the BS, and may maintain the BS synchronization using the synchronization parameters obtained through the synchronization performed immediately before. The time during which the UE can maintain the base station synchronization using the existing synchronization parameters can be changed according to various parameters such as the movement of the UE, the radio channel environment between the BS and the UE, and the UE can decide according to the situation. Therefore, a D2D terminal having a single RF receive chain can receive a D2D signal transmitted from an adjacent D2D terminal while synchronization with the base station is maintained.

8 is a flowchart illustrating a reception operation of a D2D terminal when the uplink D2D resources of a D2D UE having a single RF receive chain according to an embodiment of the present invention are overlapped with the timing of a subframe including a downlink PSS / SSS .

Referring to FIG. 8, in step 802, the D2D terminal receives D2D resource allocation information from a base station. In step 803, the D2D terminal determines whether the current uplink subframe is included in the D2D resource region based on the received D2D resource information.

If the current uplink subframe is included in the D2D resource region, the D2D terminal moves to step 804 and determines whether the current downlink subframe is a subframe including a PSS and an SSS. Alternatively, if the current uplink subframe is not included in the D2D resource region, the D2D UE may terminate the entire process and then perform the operation from the initial stage.

The D2D terminal determines in step 804 whether the current uplink frame overlaps with the downlink subframe including the PSS and the SSS. That is, the D2D UE determines whether the current downlink subframe (the downlink subframe corresponding to the current uplink frame in time) includes the PSS and the SSS. If the current downlink frame includes the PSS and the SSS, the D2D terminal moves to step 805 and determines a synchronization state with the current base station. On the other hand, if the current subframe does not include the PSS and the SSS, the D2D terminal moves to step 807 to receive the D2D signal transmitted by the neighboring terminal.

In step 805, the D2D terminal determines a synchronization state with the current base station. The D2D terminal compares the received block error rate of the control channel received from the base station or determines the synchronization state with the base station based on the quality of a reference signal transmitted from the base station can do.

If the synchronization status with the base station is not good, the D2D terminal moves to step 806 to receive the PSS and the SSS of the downlink subframe, and performs synchronization with the base station in step 808. [ On the other hand, if the D2D terminal is in good synchronization with the base station, the D2D terminal moves to step 807 and receives the D2D transmission signal of the adjacent D2D terminal transmitted in the uplink. In step 807, the D2D terminal may maintain the most recently performed base station synchronization parameter. The D2D terminal ends all the processes after steps 807 and 808, and proceeds to the start step again to perform the operations of all steps of FIG.

Second Embodiment: Reception of paging information of a terminal and overlapping timing of D2D resources

When the UE is in an idle state (RRC_IDLE) with a base station, the UE can perform a Discontinuous RX (DRX) operation to prevent power consumption of the UE. The UE in the discontinuous reception state does not receive the downlink data and the control channel transmitted from the base station during the paging cycle time interval corresponding to the certain frame. The terminal calculates a frame and a subframe through which paging information is transmitted through high-level signaling transmitted from the base station, and receives information transmitted from the base station in the frame and the subframe. Therefore, the idle terminal can obtain the change information of the network parameter state through the paging information or receive the notification of the information to be transmitted from the base station to the terminal.

A terminal in an idle state can calculate frames and subframes that must be received when performing discontinuous reception to receive paging information. The UE can calculate a frame for receiving paging information using Equation (1).

SFN mod T denotes a frame for receiving paging information, T denotes a cycle of discontinuous reception, and can be selected from a set of {32, 64, 128, 256} 2T, T, T / 2, T / 4, T / 2, and NB can be determined as a unique identifier, such as an international mobile subscriber identity (IMSI) mod 1024, 8, T / 16, and T / 32.

Also, the UE can calculate a paging occasion (PO) including paging information among the radio frames calculated in the above using Equation (2) and Table 1 below.

In Equation (2), i_s represents PO and Ns represents max (1, nB / T).

Ns PO when i_s = 0 PO when i_s = 1 PO when i_s = 2 PO when i_s = 3 One 9 N / A N / A N / A 2 4 9 N / A N / A 4 0 4 5 9

The idle terminal can calculate a frame and a subframe in which paging information should be received by using Equations (1) and (2) and Table 1 above. The terminal can receive the subframe according to i_s determined by Equation (2) in the frame including the paging information and read the paging information. Therefore, the subframe in which paging information may exist within one frame may be 0, 4, 5, and 9th subframe.

When the paging frame and the subframe for discontinuous reception of the idle terminal determined as above are overlapped with the resource area for D2D communication at the same time on the time axis, the D2D terminal having a single RF receive chain, as described above, A problem that the signal can not be received occurs. When a D2D terminal having a single RF receive chain receives a D2D signal in the uplink, the terminal does not receive paging information transmitted by the base station, and thus receives no change in the network or data coming from the terminal. Also, when the terminal receives only the paging information, a problem occurs that the adjacent D2D terminal signal is not received. Since the conventional cellular communication is more important than the D2D communication in the wireless mobile communication system in which the cellular communication is generally performed, when the reception timing of the D2D signal and the paging information are overlapped as described above, the paging information is received first, Minimize it.

As a first solution for solving the above problem, there is a method in which a terminal and a base station apply virtual i_s and Ns values instead of calculating "i_s" and "Ns" using the above equations. That is, as an embodiment of the present invention, i_s = 2 and Ns = 4 can be fixedly used for a terminal having a single RF receive chain. If i_s = 2 and Ns = 4, the paging information is included only in the fifth subframe of the UE having a single RF receive chain. Since the 5th subframe is a subframe that can be excluded by a terminal having a single RF receive chain that corresponds to a time in a downlink subframe in which PSS and SSS are transmitted, an additional subframe is not required for receiving paging information There is an advantage that it is not.

The base station can determine the values of i_s and Ns to be 2 and 4 for receiving the paging information of the D2D terminal having a single RF receive chain and can transmit virtual i_s and Ns to the corresponding D2D terminal through the base station high level signaling. Alternatively, a D2D terminal with a single RF receive chain without high level signaling at the base station can solve the problem by always using fixed values such as i_s = 2 and Ns = 4 for paging information reception in the idle state.

As another embodiment for solving the above problem, the base station has a method of excluding all downlink subframes including paging information from resources for D2D communication regardless of idle terminals. Based on Table 1 above, it can be seen that the base station transmits paging information for idle terminals in the 0, 4, 5, and 9th downlink subframes. Therefore, the BS can exclude all uplink subframes corresponding to all 0, 4, 5, and 9th downlink subframes from resources for D2D communication. For example, the base station may exclude 0, 4, 5, and 9 th uplink subframes as D2D regions. The base station can implement the embodiment by using a bitmap for resource allocation or a bit for excluding paging information in the resource allocation information as in the first embodiment.

Third Embodiment: Reception of MBMS channels and timing overlap of D2D resources

In the third embodiment of the present invention, when a D2D UE having a single RF receive chain includes MBMS and D2D signals at the same time in a cell in which a plurality of base stations provide a multimedia broadcast / multicast service (MBMS) The present invention relates to the operation of the D2D terminal.

A plurality of base stations can assign the same time and frequency resources to a physical multicast channel (PMCH) in the downlink for MBMS. The allocation of the PMCH is transmitted by signaling of the upper layer, so that the UE can not know the precise allocation information in advance. If the downlink subframe including the resource block allocated to the PMCH and the uplink subframe including the D2D signal exist at the same time on the time axis, it is impossible to simultaneously receive two signals.

Therefore, in the third embodiment of the present invention, when the D2D terminal having a single RF reception chain must simultaneously receive the PMCH and the D2D signal, the terminal selects to receive the PMCH preferentially and the D2D signal transmitted by the adjacent D2D terminal Ignore it.

Fourth Embodiment: CSI-RS / PHICH reception and timing overlap of D2D resources

In the fourth embodiment of the present invention, it is assumed that the D2D terminal having a single RF receive chain is connected to the base station (RRC_Connected).

In a wireless mobile communication system in which cellular communication is performed, a mobile station can receive data from a base station while connected to the base station, and the mobile station can also transmit data to the base station. Further, the base station can increase the data rate using a multiple input multiple output (MIMO) scheme, which is a multi-antenna scheme. In order for a base station to use a multi-antenna scheme, a base station must know the radio channel information between a plurality of antennas between the base station and the mobile station. To this end, the Node B transmits a channel state information-reference signal (CSI-RS), which is a signal for channel state information estimation in the UE. Then, the UE estimates a radio channel between multiple antennas through the CSI-RS and transmits a feedback signal based on the channel information to the base station.

The D2D terminal connected to the base station must perform D2D communication and communicate with the base station. If a terminal having a single RF receive chain must receive a D2D signal from a neighboring D2D terminal at the same time that a subframe including a CSI-RS should be received from the base station, if the terminal receives the D2D signal, Technique can not receive the signal.

Therefore, the corresponding D2D terminal receives the CSI-RS signal transmitted from the base station rather than the D2D signal, and estimates a wireless channel between the antennas.

Also, in a wireless mobile communication system in which cellular communication is performed, a hybrid automatic request (HARQ) technique is used for downlink and uplink communication in order to increase the reliability of data transmission. When the D2D terminal connected to the base station transmits data through the uplink, the base station notifies ACK / NACK information of the data to a physical HARQ indicator channel (PHICH). If the UE receives an ACK through the PHICH channel, it transmits data to be transmitted next. If the UE receives a NACK, it retransmits the previously transmitted data. The PHICH may be transmitted after the fourth subframe in the downlink when the UE transmits data through the uplink specific subframe. Therefore, there may occur a problem that the D2D reception period and the PHICH reception timing of the D2D terminal having a single RF reception chain may overlap based on the subframe basis. At this time, when the D2D terminal receives the D2D signal with priority, it is impossible to control the transmission / reception of cellular data.

Therefore, as described above, when the D2D terminal having a single RF receive chain must receive the downlink sub-frame including the PHICH and the uplink sub-frame including the D2D signal at the same time, the D2D terminal gives priority to the PHICH do.

Fifth Embodiment: Reception of D2D Signal According to RF Conversion Timing

Since a terminal having a single RF receive chain can not simultaneously receive a D2D signal and a cellular signal in an uplink and a downlink, the RF unit can receive only one signal at a specific time while switching the uplink and downlink. In order for a terminal having a single RF reception chain to receive a D2D signal and receive a downlink cellular signal or receive a downlink cellular signal and receive a D2D signal, frequency conversion of the RF section is required, A stabilization time of a predetermined time is required.

When a UE having a single RF receive chain receives the D2D signal in the uplink and performs RF frequency conversion in order to receive the downlink cellular signal, reference numeral 507 in FIG. 5 and the last OFDM symbol in the D2D subframe are not used. Thus, reference numeral 507 in FIG. 5 and the last OFDM symbol in the D2D subframe may be used for the stabilization time of the RF portion. On the other hand, when the corresponding D2D terminal receives the downlink cellular signal and switches to the uplink to receive the D2D signal, a protection time for stabilizing the RF part is required. An embodiment for solving this is as follows.

One. In order not to affect the reception of the downlink cellular signal, reception of the downlink cellular signal is completed in units of subframes, and the RF unit is switched to the uplink to receive the D2D signal. At this time, the frequency conversion of the RF unit can include one or more OFDM symbols (or SC-FDM symbols) of the first D2D subframe of the D2D resource region.

2. In order not to affect the reception of the D2D signal, the last one or more OFDM symbols of the downlink cellular subframe are used for frequency conversion of the RF section. Therefore, a UE having a single RF receive chain can receive the first D2D subframe of the D2D resource region without loss.

9 is a block diagram illustrating an internal structure of a base station that performs D2D communication resource allocation according to an embodiment of the present invention.

9, the base station includes a cell downlink resource allocation unit 901, a D2D communication resource allocation unit 902, a base station control signal generation unit 903, and a transmission unit 904. The D2D communication resource region allocating unit 902 receives downlink resource allocation information from the cellular downlink resource allocating unit 901 and allocates resources for D2D communication. The D2D communication resource area allocating unit 902 can set a priority according to the policy of the BS when the cellular downlink resource and the D2D communication resource area overlap in time. The base station control signal generator 903 generates a control signal for transmitting the downlink resource allocation information and the D2D resource allocation information to the UEs existing in the cell. The transmitter 904 may convert the base station control signal and the data signal into a signal suitable for wireless transmission and transmit the signal.

10 is a block diagram illustrating an internal structure of a UE having a D2D reception and a single RF reception chain capable of receiving a downlink cellular signal according to an embodiment of the present invention.

10, the UE includes a single RF tuner 1001, a D2D baseband receiver 1002, a downlink baseband receiver 1003, a base station control information extractor 1004, and a D2D receiver controller 1005 . The signal connection line 1006 is used for signal transmission in which inter-block data and control information are multiplexed, and the signal connection line 1007 is used for transmission of inter-block control signals.

The D2D terminal having a single RF receive chain transmits the downlink cellular signal received by the downlink baseband receiver 1003 to the base station control information extractor 1004. Then, the base station control information extraction unit 1004 extracts the base station control signal, and transmits the D2D resource area allocation information and control information related to the D2D to the D2D reception control unit 1005. [ The D2D reception controller 1005 is configured to control the D2D baseband receiver 1002 and the RF tuner 1001 to receive a D2D signal based on the D2D resource allocation information.

In the embodiment of the present invention described above, for the D2D terminal having a single RF reception chain, an efficient D2D for preventing the D2D signal transmitted in the uplink from being overlapped on the time axis by the D2D terminal adjacent to the downlink cellular signal transmitted by the base station, Resource area and cellular network configuration. Also, another embodiment of the present invention proposes an efficient operation of a UE having a single RF receive chain when the uplink D2D resource region and the downlink cellular signal overlap on the time axis.

The embodiments of the present invention disclosed in the present specification and drawings are merely illustrative examples of the present invention and are not intended to limit the scope of the present invention in order to facilitate understanding of the present 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. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as falling within the scope of the present invention.

Claims (18)

A method for transmitting resource allocation information of a base station in a wireless mobile communication system,
Generating resource allocation information for terminal-to-device (D2D) communication of a terminal including a single receiver;
And transmitting the resource allocation information to the terminal,
The resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the uplink subframe used by the base station to transmit control information Wherein the at least one downlink subframe has a different position on the time axis.
The method according to claim 1,
Wherein the control information includes at least one of a synchronization signal and paging information.
The method according to claim 1,
Wherein the resource allocation information includes a bit map composed of bit values corresponding to uplink frames included in a resource region for the D2D communication, and the resource allocation information includes a bit map corresponding to the at least one uplink sub- Wherein the at least one bit value is set to a predetermined value.
The method according to claim 1,
Wherein the resource allocation information indicates that at least one uplink subframe having the same position on the time axis as the at least one downlink subframe among the uplink frames included in the resource region for the D2D communication is not used for the D2D communication The method of claim 1, further comprising:
A method for receiving resource allocation information of a terminal including a single receiver in a wireless mobile communication system,
Receiving resource allocation information for device-to-device (D2D) communication from a base station;
And performing the D2D communication based on the resource allocation information,
The resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the uplink subframe used by the base station to transmit control information Wherein the at least one downlink subframe has a different position on the time axis.
6. The method of claim 5,
Wherein the control information includes at least one of a synchronization signal and paging information.
6. The method of claim 5,
Wherein the resource allocation information includes a bit map composed of bit values corresponding to uplink frames included in a resource region for the D2D communication, and the resource allocation information includes a bit map corresponding to the at least one uplink sub- Wherein the at least one bit value is set to a predetermined value.
6. The method of claim 5,
Wherein the resource allocation information indicates that at least one uplink subframe having the same position on the time axis as the at least one downlink subframe among the uplink frames included in the resource region for the D2D communication is not used for the D2D communication The method comprising the steps of:
A method for receiving a sub-frame of a terminal including a single receiver in a wireless mobile communication system,
Determining whether a downlink subframe including control information and an uplink subframe including a D2D signal should be received at the same time;
And receiving the downlink sub-frame preferentially when it is necessary to receive at the same time,
The control information includes at least one of ACK or NACK information, a multimedia broadcast / multicast service (MBMS) signal, and a channel state information-reference signal (CSI-RS) To the sub-frame.
In a base station in a wireless mobile communication system,
A controller for generating resource allocation information for terminal-to-device (D2D) communication of a terminal including a single receiver;
And a transmitter for transmitting the resource allocation information to the terminal,
The resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the uplink subframe used by the base station to transmit control information And a position on the time axis is different from that of at least one downlink subframe.
11. The method of claim 10,
Wherein the control information comprises at least one of a synchronization signal and paging information.
11. The method of claim 10,
Wherein the resource allocation information includes a bit map composed of bit values corresponding to uplink frames included in a resource region for the D2D communication, and the resource allocation information includes a bit map corresponding to the at least one uplink sub- Wherein at least one bit value is set to a predetermined value.
11. The method of claim 10,
Wherein the resource allocation information indicates that at least one uplink subframe having the same position on the time axis as the at least one downlink subframe among the uplink frames included in the resource region for the D2D communication is not used for the D2D communication The base station comprising:
In a terminal in a wireless mobile communication system,
A single receiving unit for receiving resource allocation information for device-to-device (D2D) communication from a base station;
And a controller for performing the D2D communication based on the resource allocation information,
The resource allocation information includes information on at least one uplink subframe that the terminal can use for the D2D communication, and the at least one uplink subframe includes information on the uplink subframe used by the base station to transmit control information And a position on the time axis is different from that of at least one downlink subframe.
15. The method of claim 14,
Wherein the control information includes at least one of a synchronization signal and paging information.
15. The method of claim 14,
Wherein the resource allocation information includes a bit map composed of bit values corresponding to uplink frames included in a resource region for the D2D communication, and the resource allocation information includes a bit map corresponding to the at least one uplink sub- Wherein at least one bit value is set to a predetermined value.
15. The method of claim 14,
Wherein the resource allocation information indicates that at least one uplink subframe having the same position on the time axis as the at least one downlink subframe among the uplink frames included in the resource region for the D2D communication is not used for the D2D communication Wherein the information includes information indicating that the terminal is not connected to the terminal.
In a terminal in a wireless mobile communication system,
A controller for determining whether a downlink subframe including control information and an uplink subframe including a D2D signal should be received at the same time,
And a single receiving unit for preferentially receiving the downlink sub-frame when it is necessary to receive at the same time,
The control information includes at least one of ACK or NACK information, a multimedia broadcast / multicast service (MBMS) signal, and a channel state information-reference signal (CSI-RS) .

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