KR20150007232A - Apparatus and method for discovery on LTE D2D communications - Google Patents

Abstract

The present invention relates to requesting for device-to-device (D2D) data communications in an LTE environment and, more specifically, to a discovery transmission system and method to transmit discovery signals for an LTE D2D communications. The discovery transmission system for LTE D2D communications comprises: a first base station which provides a mobile communications service in a wireless manner; and a first terminal which receives the mobile communications service from the first base station, wherein the first terminal performs D2D communications with at least one among a second terminal that wirelessly receives the mobile communications service from the first base station, a third terminal that receives the mobile communications service from a second base station providing wirelessly the mobile communications service in an area different from that of the first base station, and a fourth terminal that receives no mobile communications service.

Description

[0001] Apparatus and method for discovery on LTE D2D communication [

The present invention relates to a system and method for discovery transmission in LTE D2D communication, more specifically, to request data communication between terminals in an LTE environment. That is, the present invention relates to a system and a method for discovery transmission in LTE D2D communication for transmitting a terminal discovery signal for direct communication between terminals.

Data transmission is continuously increasing due to the development of LTE technology for wireless transmission of data. In addition, a large amount of data is frequently exchanged between terminals connected to a macro cell. At this time, since the macro base station occupies the wireless of the two terminals, the efficiency of the radio resources decreases. Therefore, there has been studied a method of exchanging data between terminals by minimizing the influence on a macro base station without wasting radio resources.

One of these technologies is considered to provide a technology for providing direct communication (Device-to-Device Communications) between adjacent terminals within a radius of 1 to 2 [km] located in the same or neighboring cells in a mobile communication system.

Direct communication between devices (Device to Device communication; hereinafter, mixed with D2D communication) means a communication method for performing direct data transmission / reception between two adjacent terminals without going through a base station. That is, the D2D communication technology is a technology for establishing a D2D radio link through a mobile communication air interface using a mobile communication frequency band between adjacent devices, and then directly exchanging data between the devices through the D2D wireless link without passing through the base station.

The advantages of this D2D communication technology are various. Unlike conventional WiFi Direct, Bluetooth, and Zigbee technologies that can only support communication between devices within hundreds of meters, D2D communication technology is a medium / long distance transmission Based on the capability, direct communication between devices located within a radius of 1 ~ 2 [km] is possible.

In addition, since the communication between adjacent devices does not go through the network, the load on the network can be reduced. In addition, when neighboring devices located in a cell boundary region communicate with each other via a base station, only low-speed data transmission is possible. However, when devices communicate directly, high-speed data transmission It is possible to provide a service with improved performance to users.

For example, Korean Patent Laid-Open Publication No. 10-2013-0134821 discloses a resource scheduling method for direct communication between terminals in a communication system. In this method, a mobile communication terminal for communicating with a base station for each channel, Calculating a signal to interference noise ratio (SNR) of a mobile communication terminal on the assumption that a mobile communication terminal selected for each channel and terminal closers for direct communication between terminals located within a service area of the base station are allocated, And comparing the signal-to-interference noise ratio of the mobile communication terminal with the first threshold value to determine a terminal candidate having a signal-to-interference noise ratio exceeding a first threshold value as a candidate member of a combination sharing the corresponding channel And whether or not the corresponding channel is allocated to each of the candidate members determined for each channel And the like.

However, even in this case, the channel assignment, interference cancellation, inter-terminal grouping, broadcast data transmission method, frequency sharing problem, D2D terminal search method, multi-hop method, interference with cellular, installation problem of D2D, coverage, D2D communication There is a need to solve the channel operation method and synchronization problems.

Korean Patent Publication No. 10-2013-0134821 (December 13, 2013)

It is an object of the present invention to provide a system and method for discovery transmission in LTE D2D communication requesting inter-terminal data communication in an LTE environment.

It is another object of the present invention to provide a system and method for discovery transmission in LTE D2D communication in which a terminal discovery signal for direct communication between terminals is efficiently transmitted without affecting an LTE base station.

A discovery transmission system in LTE D2D communication according to the present invention includes a first base station providing mobile communication services wirelessly and a first terminal receiving a mobile communication service from a first base station, A third terminal that receives a mobile communication service from a second base station that wirelessly provides a mobile communication service in a region other than the first base station and a third terminal that receives a mobile communication service wirelessly, 4 terminals in the D2D communication system.

Here, the first base station uses any one of allocating a new frequency, adding a sub-channel in the same frequency, and sharing the same channel in the same frequency so that the first terminal can perform D2D communication, The signal may be provided either on the uplink channel, on the downlink channel, and / or on the uplink and downlink simultaneously, and may use the radio channel of the first base station and the radio channel of the D2D At least one of a channel allocation scheme, a channel management scheme, and a duplexing scheme is used as a technique for preventing interference.

The information included in the PBCH includes the same information as the contents of the PBCH transmitted from the first base station to the first terminal, the channel bandwidth of the downlink signal for D2D, D2D , SFN for D2D, antenna usage information for D2D, information for limiting the transmission power of the terminal used in D2D, and D2D information used in neighboring base stations .

Herein, the information of D2D includes at least one of the frequency and bandwidth used by the D2D terminal, the number of used base stations, and the number of terminals communicating with the D2D terminal at the same time as the D2D terminal.

Also, the first terminal performs transmission of D2D data through the PDSCH, the information included in the PDSCH includes information identical to the PDSCH contents transmitted from the first base station to the first terminal, system information for the D2D terminal, Cell selection common reference information for the D2D terminal, neighboring cell information in the same frequency for the D2D terminal, and neighboring cell information of another frequency in the same LTE for the D2D terminal.

Here, the first terminal may perform a D2D frequency requesting operation requesting a common frequency for D2D communication with the second terminal to the first base station, a D2D frequency allocating operation of allocating a common frequency in response to the D2D frequency requesting operation, And performs a D2D frequency sharing operation of transmitting a result of the allocation operation to the second terminal.

Also, the first terminal controls the RF switch such that the timing of transmission and reception with the second terminal are opposite to each other.

Here, the first terminal requests the D2D frequency request to the second base station at the request of the D2D frequency request operation, the D2D frequency request operation in which the service provider requests the common base station for D2D communication with the different third terminal to the first base station Performs a D2D frequency allocation request operation in response to the D2D frequency allocation request in response to the D2D frequency allocation request operation, a D2D frequency allocation response operation in response to the D2D frequency allocation response in response to the D2D frequency allocation request operation, and a D2D frequency sharing operation to transmit the result of the D2D frequency allocation response operation to the third terminal.

Also, the first terminal controls the RF switch such that the timing of transmission and reception with the third terminal are opposite to each other.

Here, the first UE may transmit the AMC information to the second UE using the AMC scheme, the TTI bundling, the repeat transmission, the code spreading, the RLC segmentation, the low coding, the lower modulation scheme, the power increase, And transmits it by at least one method.

Also, the second UE may perform the same method of transmitting CNR, SNR, MER, and HARQ result of the receiving side for setting AMC to the first UE from the first base station, TTI bundling, repeat transmission, code spreading, RLC segmentation, Low coding, low-order modulation, power increase, and power density increase.

Herein, the first terminal requests a D2D frequency request operation requesting a common frequency for D2D communication with a third terminal having a different service frequency from a service provider to a first base station, a D2D frequency request operation to a second base station A D2D frequency allocation response operation that responds to the D2D frequency allocation in response to the D2D frequency allocation request operation, and a D2D frequency sharing operation that sends the result of the D2D frequency allocation response operation to the third terminal .

In addition, the first terminal includes controlling the RF switch such that the timing of transmission and reception with the third terminal are opposite to each other.

Here, the first terminal transmits a discovery signal for discovering the D2D terminal to the second terminal that performs D2D communication with the first terminal after at least 0.001 [msec] after receiving the synchronization signal at the first base station.

Also, the first terminal divides the discovery signal and the discovery message into at least one of time and frequency, and simultaneously transmits the discovery signal and the discovery message to the second terminal.

Here, the first terminal repeatedly transmits the discovery signal up to 2 to 128 times.

Also, the first terminal simultaneously transmits at least one of the first terminal ID, the second terminal ID, the broadcast information, the multicast information, and the specific information of the first terminal to the discovery signal transmitted from the first terminal.

Here, the first UE performs transmission of D2D data through one of PDCCH and PDSCH in addition to the PBCH, and the information included in the PBCH, PDCCH, and PDSCH is the same information as the PBCH content transmitted from the first base station to the first UE , The channel bandwidth of the downlink signal for D2D, the detailed structure of the PHICH channel for D2D, the SFN for D2D, the antenna usage information for D2D, the information for limiting the transmission power of the terminal used in D2D, And information on the D2D that is being processed.

The D2D information includes at least one of the frequency and bandwidth used by the D2D terminal, the number of used base stations, and the number of terminals communicating with the D2D terminal at the same time as the D2D terminal.

Here, the first MS can perform transmission of the D2D data through PDCCH, PUCCH, and PUCCH in addition to the PDSCH. The first MS can transmit the same information as PDSCH contents transmitted from the first BS to the first MS, At least one of the neighbor cell information for the D2D terminal, the cell selection common reference information for the D2D terminal, the neighbor cell information for the D2D terminal, and the neighboring cell information for the other frequency within the same LTE for the D2D terminal, .

Discovery transmission system and method in LTE D2D communication according to the present invention have an advantage of requesting data communication between terminals in an LTE environment.

Or the system and method for discovery transmission in LTE D2D communication according to the present invention can efficiently transmit a terminal discovery signal for direct communication between terminals without affecting the LTE base station.

1 is a configuration diagram of a discovery transmission system in LTE D2D communication according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a method for transmitting data using a PBCH by the first terminal of FIG. 1;
3 is a flowchart illustrating a method of transmitting data using a PDSCH by the first terminal of FIG.
4 is a flowchart illustrating a method of transmitting data when the frequencies used by the first terminal and the second terminal differ from each other in FIG.
FIG. 5 is a flowchart illustrating a method of transmitting data when the first terminal and the third terminal of FIG. 1 are different from each other.
FIG. 6 is a flowchart illustrating a method for reliably transmitting AMC by the first terminal of FIG.
FIG. 7 is a flowchart illustrating a method of transmitting data when the service frequency of the first terminal and the third terminal of FIG. 1 are different from each other.
FIG. 8 is a flowchart illustrating a method in which the first terminal of FIG. 1 transmits a discovery signal to a second terminal.
9 is a flowchart illustrating a method for the first terminal of FIG. 1 to discovery a second terminal and to transmit a message.
FIG. 10 is a flowchart illustrating a method for the first terminal of FIG. 1 to transmit a discovery signal to a second terminal.
FIG. 11 is a flowchart illustrating a method of transmitting a message for discovery by a first terminal of FIG. 1 to a second terminal.
12 is a flowchart illustrating another method of transmitting data using the PBCH by the first UE of FIG.
13 is a flowchart illustrating another method for the first terminal of FIG. 1 to transmit data using the PDSCH.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood that the present invention is not intended to be limited to the specific embodiments but includes all changes, equivalents, and alternatives included in the spirit and scope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a system and a method for a discovery transmission in LTE D2D communication according to the present invention will be described in detail with reference to the accompanying drawings.

A terminal as described herein may be referred to as a user device or user equipment (UE) and may be a cellular telephone, a satellite telephone, a cordless telephone, a Session Initiation Protocol (SIP) telephone, a wireless local loop (WLL) A personal digital assistant (PDA), a handheld device having a wireless connection capability, a computing device, or other processing devices connected to a wireless modem.

In addition, the base station described in the present invention can be used for communication with the terminal (s) and can also be referred to as an access point, a Node B, an enhanced base station (eBS) or some other terminology.

1 is a configuration diagram of a discovery transmission system in LTE D2D communication according to an embodiment of the present invention. 2 to 13 are flow charts for explaining FIG. 1 in detail.

Hereinafter, a discovery transmission system in LTE D2D communication according to an embodiment of the present invention will be described with reference to FIG. 1 to FIG.

Referring to FIG. 1, a discovery transmission system in LTE D2D communication according to an embodiment of the present invention includes a first base station 310 for providing a mobile communication service and a first base station 310 for providing a mobile communication service The first terminal 130 includes a second terminal 110 and a first base station 310 that receive mobile communication services from the first base station 310 through wireless communication with the first terminal 130, A third terminal 240 receiving a mobile communication service from a second base station 320 wirelessly providing a mobile communication service in a region and a fourth terminal 140 receiving a mobile communication service, And performing communication.

Here, the first base station 310 allocates a new frequency, allocates a sub-channel in the same frequency, and shares the same channel in the same frequency so that the first terminal 130 can perform D2D communication And the synchronization signal between the D2Ds is used either on the uplink channel, on the downlink channel, or on the uplink and downlink simultaneously, At least one of a channel allocation scheme, a channel management scheme, and a duplexing scheme may be used as a scheme for preventing interference of a radio channel of the D2D performed by the UE.

D2D communication can be divided into discovery to find a D2D terminal for D2D data communication and D2D communication to actually communicate later.

First, Discovery includes a signal required to find a D2D terminal and discovery information and channel prediction information in a message.

The frames used for discovery messages and sequences can be used similar to the PUSCH of the LTE uplink, discovery at short distances using the normal cyclic prefix, and discovery at the extended range, Use an extended cyclic prefix.

QPSK, turbo codes, interleavers, and CRC-24 are used for transmission of discovery messages and sequences.

Discovery messages and sequences are transmitted at the same frequency and at the same time.

On the other hand, D2D communication is used for D2D communication, and includes the use of physical channels for synchronization and communication between terminals.

The synchronization of the D2D communication is for synchronizing the terminals by transmitting the D2D synchronization signal, and uses the same frequency and time between the terminals.

The synchronization sequence of the D2D communication includes at least one of a ZC sequence or an M sequence.

The synchronization content of the D2D communication includes at least any one of an ID of a synchronization source for transmitting a synchronization signal, a format of a synchronization source, a resource allocation of a control signal, and data.

The physical channel for D2D communication includes a D2DSS (D2D Synchronization Signal) for transmitting a D2D synchronization signal, a Physical D2D Synchronization Channel (PD2DSCH) as a physical D2D synchronization channel, a cluster head control channel (CH-CCH) A cluster head data channel (CH-DCH), a D2D data channel, and a REQ (request) channel for requesting a resource.

Here, the D2DSS transmits in the cluster head of the synchronization of the cluster constituted by the D2D terminal and provides a synchronization reference.

The PD2DSCH includes synchronization information in the cluster head, that is, SFN, synchronization status, and setting information, that is, channel bandwidth, resource setting information, and the like.

On the other hand, the CH-CCH is transmitted to the transmitting terminal and the receiving terminal in the cluster head in the cluster head and includes transmission information for transmission and does not include a control part for decoding.

Also, the CH-DCH is transmitted from the cluster head to the transmitting terminal and the receiving terminal in the cluster, and transmits the data to be transmitted by the scheduling of the CH-CCH.

The D2D data channel monitors CH-CCH information through a channel through which data is transmitted to a receiving terminal, and transmits the D2D data channel through the allocated resource.

The REQ channel is a channel used when the transmitting terminal requests resource allocation to the cluster head. It requests D2D buffer status, interference information measured by the transmitting terminal, usable transmission power, etc., and the REQ channels of the transmitting terminals are separated into frequencies and transmitted to the cluster head.

Therefore, the D2DSS, the PD2DSCH, the CH-CCH, and the CH-SCH used for transmission from the cluster to the UE, the REQ channel used for transmission from the UE to the cluster head, and the D2D data channel used between the UEs, SSS, PDCCH, and PUCCH.

FIG. 2 is a flowchart illustrating a method of transmitting data using the PBCH by the first terminal 130 of FIG. Here, the first terminal 130 performs transmission of D2D data through the PBCH, and the information included in the PBCH includes the same information as the PBCH contents transmitted from the first base station 310 to the first terminal 130, D2D A detailed structure of the PHICH channel for D2D, SFN for D2D, antenna usage information for D2D, information for limiting the transmission power of the terminal used in D2D, and D2D And the information of the < / RTI >

Here, the information of D2D may include at least one of the frequency and bandwidth used by the D2D terminal, the number of used base stations, and the number of terminals communicating with the D2D terminal at the same time as the D2D terminal.

The base station PBCH information S102 is broadcast information transmitted from the first base station 310 to the first terminal 130 and the base station PBCH information S302 is broadcast information transmitted to the second terminal 110. [ The base station PBCH information (S102) and the base station PBCH information (S302) contain the same contents and are information used for broadcasting such as normal base station information in the LTE base station.

The base station PBCH information S202 is broadcast information transmitted from the second base station 320 to the third terminal 240 and includes information different from the base station PBCH information S102 transmitted from the first base station 310. [

The D2D PBCH information (S402) is broadcast information transmitted from the first terminal 130 to the second terminal 110, and further includes information related to D2D in addition to the content normally used in the LTE base station. The D2D PBCH information S502 is broadcast information transmitted from the first terminal 130 to the third terminal 240 and includes the same contents as the D2D PBCH information S402. The D2D PBCH information S602 is broadcast information transmitted from the first terminal 130 to the fourth terminal 140 and includes the same contents as the D2D PBCH information S402.

FIG. 3 is a flowchart illustrating a method of transmitting data using the PDSCH by the first terminal 130 of FIG. Here, the first terminal 130 performs transmission of D2D data through the PDSCH, and the information included in the PDSCH includes information identical to the PDSCH contents transmitted from the first base station 310 to the first terminal 130, Cell selection common reference information for the D2D terminal, neighbor cell information in the same frequency for the D2D terminal, and neighboring cell information for other frequencies in the same LTE for the D2D terminal, And may include at least any one of them.

The base station PDSCH information S103 is downlink information transmitted from the first base station 310 to the first terminal 130 and the base station PDSCH information S303 is downlink information transmitted to the second terminal 110. [ The base station PDSCH information (S103) and the base station PDSCH information (S303) contain the same contents and are information that is commonly used as downlink information in the LTE base station.

Meanwhile, the base station PDSCH information (S203) includes downlink information transmitted from the second base station 320 to the third terminal 240 and includes information different from the base station PDSCH information (S103) transmitted from the first base station 310 .

The D2D PDSCH information (S403) is downlink information transmitted from the first terminal 130 to the second terminal 110, and further includes information related to the D2D in addition to the contents normally used by the LTE base station. The D2D PDSCH information S503 is downlink information transmitted from the first terminal 130 to the third terminal 240 and includes the same contents as the D2D PDSCH information S403. The D2D PDSCH information S603 is also downlink information transmitted from the first terminal 130 to the fourth terminal 140 and includes the same contents as the D2D PDSCH information S403.

4 is a flowchart illustrating a method of transmitting data when the frequencies used by the first terminal 130 and the second terminal 110 are different from each other. Here, the first terminal 130 may request the D2D frequency request operation (S104) and the D2D frequency request operation (S104) to request the first base station 310 for a common frequency for D2D communication with the second terminal 110 A D2D frequency allocation operation S304 for allocating a common frequency in response to the D2D frequency allocation operation S304 and a D2D frequency sharing operation S404 for transmitting the result of the D2D frequency allocation operation S304 to the second terminal 110. [

Also, the first terminal 130 can control the RF switch such that the transmission and reception timings with respect to the second terminal 110 are opposite to each other.

The assignment in the D2D frequency allocation operation S304 may be allocated to frequencies other than those used by the first terminal 130 and the second terminal 110. [

The first terminal 130 receives D2D communication between the first terminal 130 and the second terminal 110 because the second terminal 110 receives the mobile communication service from the first base station 310, May be allocated from the first base station 310. [

Meanwhile, since the first terminal 130 can not perform the D2D communication without solving the radio frequency interference problem with the third terminal 240 or the fourth terminal 140 that is not provided with the mobile communication service through the same base station, 240 or the fourth terminal 140 to request D2D frequency sharing.

The new radio resources in the TDD (Time Division Duplex) scheme are one frequency that the first terminal 130 and the second terminal 110 can commonly use. The RF switch in the first terminal 130 and the second terminal 110 must be controlled so that the transmission and reception timings of the first terminal 130 and the second terminal 110 may be opposite to each other.

The new radio resource in the frequency division duplex (FDD) scheme uses different frequencies from the first terminal 130 to the second terminal 110 and from the second terminal 110 to the first terminal 130 do. The RF switch in the first terminal 130 and the second terminal 110 must be controlled so that the transmission and reception timings of the first terminal 130 and the second terminal 110 may be opposite to each other.

After the allocation of radio resources is completed, D2D communication is performed through any one of PDCCH, PDSCH, PUCCH, and PUSCH, which are basic radio channels of LTE.

FIG. 5 is a flowchart illustrating a method of transmitting data when the first terminal 130 and the third terminal 240 of FIG. 1 are different from each other. Here, the first terminal 130 includes a D2D frequency requesting operation (S105) and a D2D frequency requesting operation (step S105) in which the service provider requests the first base station 310 for a common frequency for D2D communication with the third terminal 240, A D2D frequency allocation requesting operation (S205) for requesting the D2D frequency allocation to the second base station 320 at the request of the D2D frequency allocation requesting operation (S105), a D2D frequency allocation requesting operation (S305), and a D2D frequency sharing operation (S505) for transmitting the result of the D2D frequency allocation response operation (S305) to the third terminal (240).

Also, the first terminal 130 can control the RF switch such that the timing of transmission and reception with the third terminal 240 are opposite to each other.

Meanwhile, the response in the D2D frequency allocation response operation (S305) may be received at a frequency other than the frequency used by the first terminal 130 and the third terminal 240. [

The new radio resource in the TDD scheme is one frequency that the first terminal 130 and the third terminal 240 can commonly use. In this case, the RF switch in the first terminal 130 and the third terminal 240 should be controlled so that the transmission and reception timings of the first terminal 130 and the third terminal 240 may be opposite to each other.

The new radio resource in the FDD scheme uses the frequency from the first terminal 130 to the third terminal 240 and the frequency from the third terminal 240 to the first terminal 130 differently. In this case, the RF switch in the first terminal 130 and the third terminal 240 should be controlled so that the transmission and reception timings of the first terminal 130 and the third terminal 240 may be opposite to each other.

After the allocation of radio resources is completed, D2D communication is performed through any one of PDCCH, PDSCH, PUCCH, and PUSCH, which are basic radio channels of LTE.

FIG. 6 is a flowchart illustrating a method for the first terminal 130 of FIG. 1 to reliably transmit AMC. The first terminal 130 transmits AMC information to the second terminal 110 through the AMC method used by the first base station 310, TTI bundling, repeated transmission, code spreading, RLC segmentation, low coding, , Power increase, and power density increase.

Also, the second terminal 110 may perform the same method of transmitting CNR, SNR, MER, and HARQ result of the receiving side for setting AMC to the first terminal 130 from the first base station 310, TTI bundling, It may be transmitted at least one of iterative transmission, code spreading, RLC segmentation, low coding, lower order modulation, power increase, and power density increase.

Here, CNR (Carrier to Noise Ratio), SNR (Signal to Noise Ratio), and MER (Message Error Ratio) are measures for the quality of reception, and HARQ (Hybrid ARQ) .

That is, the AMC configuration information (S106) and the AMC information (S206) used in the first terminal 130 and the first base station 310 are transmitted to the first terminal 130 and the second terminal 110, It is possible to use TTI bundling, repetitive transmission, code spreading, RLC segmentation, low coding, lower order modulation, power increase, and power density increase, etc., including the same information as S306 and AMC information S406.

FIG. 7 is a flowchart illustrating a method of transmitting data when a service provider of the first terminal 130 and the third terminal 240 of FIG. 1 and a use frequency are different from each other. The D2D frequency requesting operation (S107) for requesting the first base station 310 for a common frequency for D2D communication with the third terminal 240 having a different frequency of use from the service provider, A D2D frequency allocation request operation (S207) for requesting the D2D frequency allocation to the second base station 320 at the request of the requesting operation (S107), a D2D frequency allocation requesting operation (S207) for responding to the D2D frequency allocation in response to the D2D frequency allocation requesting operation The D2D frequency sharing operation S507 of transmitting the result of the assignment response operation S307 and the D2D frequency allocation response operation S307 to the third terminal 240 is performed.

Also, the first terminal 130 may include controlling the RF switch such that the timing of transmission and reception with the third terminal 240 are opposite to each other.

Meanwhile, the response in the D2D frequency allocation response operation (S307) may be received at a frequency other than the frequency used by the first terminal 130 and the third terminal 240. [

The new radio resource in the TDD scheme is one frequency that the first terminal 130 and the third terminal 240 can commonly use. In this case, the RF switch in the first terminal 130 and the third terminal 240 should be controlled so that the transmission and reception timings of the first terminal 130 and the third terminal 240 may be opposite to each other.

The new radio resource in the FDD scheme uses the frequency from the first terminal 130 to the third terminal 240 and the frequency from the third terminal 240 to the first terminal 130 differently. In this case, the RF switch in the first terminal 130 and the third terminal 240 should be controlled so that the transmission and reception timings of the first terminal 130 and the third terminal 240 may be opposite to each other.

After the allocation of radio resources is completed, D2D communication is performed through any one of PDCCH, PDSCH, PUCCH, and PUSCH, which are basic radio channels of LTE.

FIG. 8 is a flowchart illustrating a method for transmitting the discovery signal to the second terminal 110 by the first terminal 130 of FIG. The first terminal 130 receives the synchronization signal from the first base station 310 and transmits the synchronization signal to the second terminal 110 that performs D2D communication with the first terminal 130 at least after 0.001 msec. Lt; RTI ID = 0.0 > discovery < / RTI >

In this case, when the signal of the discovery is less than 0.001 [msec], the synchronization signal generated in the first base station 310 is generated in the first terminal 130 due to the signal delay due to the radio environment fading upon reception at the second terminal 110 The interference of the discovery signal and the reception of the discovery signal can be affected.

That is, the first base station 310 transmits only the discovery signal time allocated to the first terminal 130 regardless of whether the first base station 310 operates as FDD or TDD.

In the case of TDD, the first terminal 130 transmits a discovery signal in the forward time of the first base station 310 when the first base station 310 is transmitting a synchronization signal, and the method in which the first base station 310 transmits the discovery signal in the reverse direction There is a method in which the first terminal 130 transmits a discovery signal.

When the first terminal 130 transmits the discovery signal in the forward time after receiving the synchronization signal, the first terminal 130 transmits the discovery signal to the predefined frame so as to be able to transmit the discovery signal.

Further, the RF power is adjusted so as not to affect the first base station 310 when transmitting in the reverse time.

In the case of FDD, the first base station 310 is operating in forward and reverse directions at the same time. At this time, the first terminal 130 has a method of transmitting a discovery signal on a forward channel and a method of transmitting on a reverse channel.

When the first terminal 130 transmits the discovery signal in the forward time after receiving the synchronization signal, the first terminal 130 transmits the discovery signal to the predefined frame so as to be able to transmit the discovery signal.

Also, when transmitting on the reverse channel, the first terminal 130 can transmit the synchronization signal immediately after receiving the synchronization signal, and controls the RF power so as not to affect the first base station 310.

FIG. 9 is a flowchart illustrating a method for the first terminal 130 of FIG. 1 to discovery the second terminal 110 and to transmit a message. Here, the first terminal 130 may transmit the discovery signal and the discovery message S117 at the same time by distinguishing at least one of the time and frequency of the discovery signal and the discovery message to the second terminal 110. [

That is, the discovery signal among the discovery signal and the discovery message S117 is a signal transmitted from the first terminal 130 to the second terminal 110 to search for the second terminal 110, and the discovery message is information on discovery . The discovery signal and the discovery message constitute a discovery signal and a discovery message S117 so that they can be simultaneously transmitted using different time and frequency.

There are strong advantages in frequency selective fading when using time division, and it is advantageous against time error when using frequency division.

On the other hand, when time and frequency are used at the same time, there is a strong advantage in frequency selective fading and time burst error.

The distinction between the discovery signal and the discovery message is controlled by the first base station 310 but is controlled by the first terminal 130 when the signal of the first base station 310 is insufficient.

Meanwhile, the discovery signal and the discovery message S217 are sent from the first terminal 130 to the third terminal 240, and the discovery signal and the discovery message S317 are transmitted from the first terminal 130 to the fourth terminal 140).

10 is a flowchart illustrating a method of transmitting the discovery signal to the second terminal 110 by the first terminal 130 of FIG. Here, the first terminal 130 may transmit the discovery signal repeatedly up to 2 to 128 times.

The first terminal 130 transmits a discovery signal S218 to find the second terminal 110. [ The discovery signal S218 uses the PUSCH DMRS defined in the Rel-8 of the 3GPP of the International Standardization Conference and repeats the discovery signal S218 up to a maximum of 2 to 128 times to improve reception performance.

The reception performance depends on the location of the first terminal 130 and the second terminal 110, and the terminal may control the repeater frequency to gradually increase the occupation of the radio channel.

The first base station 310 may transmit the information on the designation of the number of times of repetition of the discovery signal S118 to the first terminal 130 by designating the number of repetition of the discovery signal S218 transmitted from the first terminal 130 The fourth terminal 140 which is not under the control of the first base station 310 specifies the repetition number of the discovery signal S318 in the fourth terminal 140 and sends it to the fifth terminal 160.

FIG. 11 is a flowchart illustrating a method of transmitting a message for discovery of a second terminal 110 by the first terminal 130 of FIG. Herein, the first terminal 130 receives the first terminal 130 ID, the second terminal 110 ID, the broadcast information, the multicast information, and the first terminal 130 in the discovery signal transmitted from the first terminal 130 130 can be transmitted at the same time.

Here, the specific information may mean all information about the owner of the first terminal 130, such as age, company type, and gender. Therefore, the first terminal 130 can additionally transmit specific information to the discovery signal, thereby connecting the D2D terminal only when the D2D terminal receives the specific information, thereby simplifying the connection procedure.

The first terminal 130 transmits the discovery signal S121 to the second terminal 110 and the discovery signal S121 transmits the discovery signal S221 to the third terminal 240 from the first terminal 130 Is the same signal as the discovery signal S321 transmitted from the first terminal 130 to the fourth terminal 140. [

The second terminal 110 performs D2D communication by responding to the first terminal 130 with a discovery response S421 as a terminal corresponding to the discovery signal S121 transmitted from the first terminal 130. [

12 is a flowchart illustrating another method of transmitting data using the PBCH by the first terminal 130 of FIG. Here, the first terminal 130 performs transmission of D2D data through one of PDCCH and PDSCH in addition to the PBCH, and information included in the PBCH, PDCCH, and PDSCH is transmitted from the first base station 310 to the first terminal 130 ), The channel bandwidth of the downlink signal for D2D, the detailed structure of the PHICH channel for D2D, the SFN for D2D, the antenna usage information for D2D, and the transmit power of the terminal used for D2D Limited information, and D2D information used in a neighboring base station.

The information of D2D may include at least any one of the frequency and bandwidth used by the D2D terminal, the number of used base stations, and the number of terminals communicating with the D2D terminal at the same time as the D2D terminal.

The base station PBCH information S122 is broadcast information transmitted from the first base station 310 to the first terminal 130 and the base station PBCH information S322 is broadcast information transmitted to the second terminal 110. [ The base station PBCH information (S122) and the base station PBCH information (S322) contain the same contents and are information used for broadcasting such as base station information in the LTE base station.

The base station PBCH information S222 is broadcast information transmitted from the second base station 320 to the third terminal 240 and includes information different from the base station PBCH information S122 transmitted from the first base station 310. [

The D2D PBCH information S422 is broadcasting information transmitted from the first terminal 130 to the second terminal 110, and further includes information related to the D2D in addition to contents normally used in the LTE base station. The D2D PBCH information S522 is broadcast information transmitted from the first terminal 130 to the third terminal 240 and includes the same contents as the D2D PBCH information S422. The D2D PBCH information S622 is broadcast information transmitted from the first terminal 130 to the fourth terminal 140 and includes the same contents as the D2D PBCH information S422.

FIG. 13 is a flowchart illustrating another method for the first terminal 130 of FIG. 1 to transmit data using the PDSCH. Herein, the first terminal 130 may perform transmission of D2D data through one of PDCCH, PUCCH, and PUCCH in addition to the PDSCH, and may transmit the PDSCH contents transmitted from the first base station 310 to the first terminal 130 Cell selection common reference information for the D2D terminal, neighboring cell information in the same frequency for the D2D terminal, and other information in the same LTE for the D2D terminal, And surrounding cell information of the frequency.

The base station PDSCH information S123 is downlink information transmitted from the first base station 310 to the first terminal 130 and the base station PDSCH information S323 is downlink information transmitted to the second terminal 110. [ The base station PDSCH information (S123) and the base station PDSCH information (S323) contain the same contents and are information that is commonly used as downlink information in the LTE base station.

The base station PDSCH information S223 includes downlink information transmitted from the second base station 320 to the third terminal 240 and includes information different from the base station PDSCH information S123 transmitted from the first base station 310 .

The D2D PDSCH information S423 is downlink information transmitted from the first terminal 130 to the second terminal 110 and further includes information related to the D2D in addition to the contents normally used by the LTE base station. The D2D PDSCH information S523 is downlink information transmitted from the first terminal 130 to the third terminal 240 and includes the same contents as the D2D PDSCH information S423. The D2D PDSCH information S623 is also downlink information transmitted from the first terminal 130 to the fourth terminal 140 and includes the same contents as the D2D PDSCH information S423.

As described above, the system and method for discovery transmission in LTE D2D communication according to the present invention have an advantage of requesting data communication between terminals in an LTE environment, and can efficiently transmit terminal discovery signals for direct communication between terminals without affecting LTE base stations And the like.

It will be appreciated that any particular order or hierarchy of steps in any of the presented processes is an example of exemplary approaches. It will be appreciated that, based on design priorities, certain orders or hierarchies of steps in processes may be rearranged within the scope of the present invention.

The appended method claims provide elements of the various steps in an exemplary order, but are not meant to be limited to the specific order or hierarchy presented.

The steps and / or operations of the method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two .

The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

An exemplary storage medium may be coupled to a machine, such as a computer or processor (which may be referred to as a ' processor ' for convenience), such that the processor reads information (e.g., software instructions) And record information on a storage medium. Alternatively, the storage medium may be integrated into the processor.

Further, in some aspects, the processor and the storage medium may be included within an ASIC. Additionally, the ASIC may be included within the user equipment. Alternatively, the processor and the storage medium may be included as separate components within the user device.

Additionally, in some aspects, the steps and / or operations of a method or algorithm may reside as one or any combination or set of codes and / or instructions on a machine readable medium and / or computer readable medium.

In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium.

Computer-readable media can include both computer storage media and any communication media including any medium that facilitates movement of a computer program from one place to another. The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention.

Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention.

Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (20)

A first base station for wirelessly providing mobile communication services; And
And a first terminal for receiving a mobile communication service from the first base station, wherein the first terminal comprises: a second terminal for receiving a mobile communication service from the first base station by radio; A third terminal that receives a mobile communication service from a second base station that wirelessly provides a communication service, and a fourth terminal that is not provided with a mobile communication service, in the LTE D2D communication including performing D2D communication with at least one of Discovery transmission system. The method according to claim 1,
The first base station may use any one of allocating a new frequency, adding a sub-channel in the same frequency, and sharing the same channel in the same frequency so that the first terminal can perform D2D communication, The synchronization signal may be provided either on the uplink channel, on the downlink channel, and / or on the uplink and the downlink simultaneously, and may use the radio channel of the first base station and the D2D Wherein at least one of a channel allocation scheme, a channel management scheme, and a duplexing scheme is used as a scheme for preventing interference of a wireless channel. The method according to claim 1,
The first terminal performs transmission of D2D data through the PBCH, and the information included in the PBCH includes the same information as the contents of the PBCH transmitted from the first base station to the first terminal, the channel band of the downlink signal for D2D Width, a detailed structure of the PHICH channel for D2D, SFN for D2D, antenna usage information for D2D, information for limiting the transmission power of the terminal used in D2D, and information of D2D used in peripheral base station And a discovery transmission system in the LTE D2D communication. The method of claim 3,
Wherein the D2D information includes at least one of a frequency and a bandwidth used by the D2D terminal and a number of terminals communicating with the using base station and the D2D terminal at the same time as the D2D terminal. Transmission system. The method according to claim 1,
Wherein the first terminal performs transmission of D2D data through a PDSCH, the information included in the PDSCH includes information identical to PDSCH contents transmitted from the first base station to the first terminal, system information for a D2D terminal, At least one of the neighboring cell information for the D2D terminal, the cell selection common reference information for the D2D terminal, the adjacent cell information for the D2D terminal, and the neighbor cell information for the other frequency in the same LTE for the D2D terminal Wherein the at least one of the at least two antennas comprises at least one of the plurality of antennas. The method according to claim 1,
The first terminal requesting a common frequency for D2D communication with the second terminal to the first base station;
A D2D frequency allocation operation that allocates the common frequency in response to the D2D frequency request operation; And
And transmitting a result of the D2D frequency allocation operation to the second terminal. The method according to claim 6,
Wherein the first terminal controls the RF switch such that the transmission and reception timings of the first terminal and the second terminal are opposite to each other. The method according to claim 1,
Wherein the first terminal requests the D2D frequency request operation to the first base station for a common frequency for D2D communication with the third terminal different from the service provider;
A D2D frequency allocation request operation requesting a D2D frequency allocation to the second base station at the request of the D2D frequency requesting operation;
The D2D frequency allocation response operation responsive to the D2D frequency allocation in response to the D2D frequency allocation request operation; And
And transmitting a result of the D2D frequency allocation response operation to the third terminal. 9. The method of claim 8,
Wherein the first terminal controls the RF switch so that the transmission and reception timings of the third terminal and the third terminal are opposite to each other. The method according to claim 1,
The first terminal may transmit AMC information to the second terminal using an AMC method, TTI bundling, repeat transmission, code spreading, RLC segmentation, low coding, lower order modulation, power increase, and power density Wherein the transmission is performed by at least one of the following methods. The method according to claim 1,
The second UE may perform the same method of transmitting CNR, SNR, MER, and HARQ result of the receiving side for setting AMC to the first UE from the first BS, TTI bundling, repeat transmission, code spreading, RLC Segmentation, low coding, low-order modulation, power increase, and power density increase. The method according to claim 1,
Wherein the first terminal requests the D2D frequency request to the first base station for a common frequency for D2D communication with the third terminal having a different frequency of use from the service provider;
Requesting D2D frequency allocation to the second base station at the request of the D2D frequency requesting operation;
The D2D frequency allocation response operation responsive to the D2D frequency allocation in response to the D2D frequency allocation request operation; And
And the D2D frequency sharing operation to transmit the result of the D2D frequency allocation response operation to the third terminal. 13. The method of claim 12,
And the first terminal includes controlling the RF switch such that the transmission and reception timings of the third terminal and the third terminal are opposite to each other. The method according to claim 1,
The first terminal transmits a discovery signal for discovering the D2D terminal to the second terminal that performs D2D communication with the first terminal after at least 0.001 msec after receiving the synchronization signal from the first base station Wherein the discovery transmission system in the LTE D2D communication is characterized in that: The method according to claim 1,
Wherein the first terminal divides a discovery signal and a discovery message into at least one of time and frequency, and transmits a discovery signal and a discovery message to the second terminal at the same time. The method according to claim 1,
Wherein the first terminal repeatedly transmits a discovery signal up to 2 to 128 times. The method according to claim 1,
Wherein the first terminal transmits at least one or more of the first terminal ID, the second terminal ID, the broadcast information, the multicast information, and the specific information of the first terminal to the discovery signal transmitted from the first terminal And transmitting the same at the same time. The method according to claim 1,
The first terminal performs transmission of D2D data through one of a PDCCH and a PDSCH in addition to the PBCH, and information included in the PBCH, the PDCCH, and the PDSCH is transmitted from the first base station to the first terminal The channel bandwidth of the downlink signal for D2D, the detailed structure of the PHICH channel for D2D, the SFN for D2D, the antenna usage information for D2D, the information for limiting the transmission power of the terminal used in D2D, And information of D2D used in a neighboring base station. 19. The method of claim 18,
Wherein the D2D information includes at least one of a frequency and a bandwidth used by the D2D terminal and a number of terminals communicating with the using base station and the D2D terminal simultaneously with the D2D terminal. Discovery transmission system. The method according to claim 1,
The first terminal may perform transmission of D2D data through a PDCCH, a PUCCH, and a PUCCH in addition to the PDSCH. The first terminal may transmit the same information as PDSCH contents transmitted from the first base station to the first terminal, , Cell selection common reference information for the D2D terminal, neighbor cell information in the same frequency for the D2D terminal, and neighboring cell information for the D2D terminal in the same LTE And cell information. The system of claim 1,

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