Methods and apparatus for device-to-device communications system

1. A method, comprising:

configuring one or more pools of Device-to-Device (D2D) communication resources by an eNodeB (eNB);

signaling information regarding the one or more configured pools of D2D communication resources by the eNB to a first User Equipment (UE) and a plurality of UEs using a common broadcast channel;

receiving a request for one or multiple D2D communication resources by the eNB from the first UE, wherein the first UE is configured to transmit D2D messages;

determining one or multiple resources for D2D communication by the eNB for the first UE; and

communicating a D2D resource allocation information to the first UE, wherein the first UE communicates the D2D resource allocation information to one or more of the plurality of UEs and transmits D2D data to one or more of the plurality of UEs when the D2D resource allocation information is received from the eNB,

wherein a format for communicating the D2D resource allocation information includes an indication of time/frequency physical resources for D2D data transmission and an identification of transmission channel identity for D2D control channel transmission, and

wherein, when the first UE is within a network coverage, D2D signals are transmitted using at least one of timing and frequency of a serving cell's uplink transmission,

wherein the first UE is configured to function as a relay for D2D synchronization transmission, configuration transmission, D2D control channel transmission and reception, and D2D data channel transmission and reception with one of the plurality of UEs that is not within the network coverage.

2. The method of claim 1 , further comprising:

receiving a request for one or more D2D communication resources from the first EE using one of: a random access procedure, or a scheduling request message, or a higher layer message,

wherein for random access procedure, D2D resource request information is received in a Message 3 of the random access procedure,

wherein the D2D resource request information includes a priority of request, an amount of resources required, and a required length of resource reservation period.

3. The method of claim 1 , wherein communicating the D2D resource allocation information comprises using a higher layer message or a layer 1 control signaling,

wherein the format is a Downlink Control information (DCI) format, wherein the layer 1 control signaling is carried by a Physical Downlink Control Channel (PDCCH) with the DCI format, and

wherein the DCI format is DCI format 0.

4. The method of claim 3 , further comprising:

identifying whether the DCI format is for a conventional purpose or for D2D resource allocation,

wherein the DCI format for D2D resource allocation is further identified using predetermined values for a set of parameters in the DC format,

wherein a parameter of the set of parameters is at least one of: a modulation and coding scheme and redundancy version,

wherein a parameter of the set of parameters is a number of physical resource blocks indicated by a resource block assignment and hopping resource allocation field.

5. The method of claim 1 , wherein

the first UE communicates D2D resource allocation information corresponding to the D2D data to be transmitted to the one or more of the plurality of UEs using a D2D control channel before transmitting D2D data,

wherein the D2D control channel includes at least one of

modulation and coding scheme information,

time and frequency physical resources for D2D transmission, and

a transmission channel identity.

6. The method of claim 1 , wherein for the first UE, D2D signals and conventional UL signals are transmitted in a time-division multiplexing manner.

7. The method of claim 1 , further comprising:

determining D2D transmit timing,

wherein one or more synchronization signals are transmitted by the first UE if the first UE is out of network coverage, and

wherein the one or more synchronization signals comprise one of Primary Synchronization Signals, Secondary Synchronization Signals, or a Zadoff Chu sequence.

8. A method comprising:

configuring one or more pools of device-to-device (D2D) communication resources by an enhanced Node B (eNB); and

signaling, by the eNB, the configured one or more pools of D2D communication resources to a first user equipment (UE) and a plurality of UEs using a common broadcast channel, wherein in response to the signaling of the configured one or more pools of D2D communication resources, the first UE:

chooses from the one or more pools of D2D communication resource, one or more D2D resources for D2D transmissions;

communicates D2D resource allocation information to at least one UE of the plurality of UEs; and

transmits D2D data to the at least one UE of the plurality of UEs when the D2D resource allocation information is received from the eNB,

wherein a format for communicating the D2D resource allocation information includes an indication of time/frequency physical resources for D2D data transmission and an identification of transmission channel identity for D2D control channel transmission, and

wherein, when the first UE is within a network coverage, the D2D data is transmitted using at least one of timing and frequency of a serving cell's uplink transmission,

wherein the first UE is configured to function as a relay for D2D synchronization transmission, configuration transmission, D2D control channel transmission and reception, and D2D data channel transmission and reception with one of the plurality of UEs that is not within the network coverage.

9. The method of claim 8 , wherein the first UE can perform channel listening before choosing a resource for D2D transmission.

10. The method of claim 8 , wherein the first UE communicates D2D resource allocation information corresponding to the D2D data to be transmitted to the at least one UE of the plurality of UEs using a D2D control channel before transmitting the D2D data, and

wherein the D2D resource allocation information includes at least one of

modulation and coding scheme information,

time and frequency physical resources for D2D transmission, and

a transmission channel identity.

11. The method of claim 8 , wherein for the first UE, D2D signals and conventional UL signals are transmitted in a time-division multiplexing manner, the D2D signals comprising the D2D data.

12. The method of claim 11 , further comprising:

determining D2D transmit timing,

wherein the D2D signals comprise the D2D data,

wherein one or more synchronization signals are transmitted by the first UE if the first UE is out of network coverage, and

wherein the one or more synchronization signals comprise one of Primary Synchronization Signals, Secondary Synchronization Signals, and a Zadoff Chu sequence.

13. A user equipment (UE) configured for D2D communication, the UE comprising:

a processing circuitry configured to:

receive configuration of one or more pools of device-to-device (D2D) communication resources by an enhanced Node B (eNB) through a common broadcast channel;

send a request for one or more D2D communication resources to the eNB;

receive D2D resource allocation information from the eNB;

communicate D2D resource allocation information to one or more UEs; and

transmit D2D data to the one or more UEs when the D2D resource allocation information is received from the eNB,

wherein a format for communicating the D2D resource allocation information includes an indication of time/frequency physical resources for D2D data transmission and an identification of transmission channel identity for D2D control channel transmission, and

wherein, when the UE is within a network coverage, D2D signals are transmitted using at least one of timing and frequency of a serving cell's uplink transmission,

wherein a first UE of the one or more UEs functions as a relay for D2D synchronization transmission, configuration transmission, D2D control channel transmission and reception, and D2D data channel transmission and reception with another of the one or more UEs that is not within the network coverage.

14. The UE of claim 13 , wherein a request for one or multiple D2D communication resources is sent using one of: a random access procedure, or a scheduling request message, or a higher layer message,

wherein for random access procedure, D2D resource request information is transmitted in a Message 3 of the random access procedure,

wherein the D2D resource request information includes a priority of request, an amount of resources required, and a required length of resource reservation period.

15. The UE of claim 13 , wherein D2D resource allocation information is received using a higher layer message or a layer 1 control signaling,

wherein the format is a Downlink Control Information (DCI) format,

wherein the layer 1 control signaling is carried by a Physical Downlink Control Channel (PDCCH) with the DCI format, and

wherein the DCI format is DCI format 0.

16. The UE of claim 15 , wherein the DCI format for D2D resource allocation is further identified using predetermined values for a set of parameters in the DCI format,

wherein a parameter of the set of parameters is one of a modulation and coding scheme and redundancy version,

wherein a parameter of the set of parameters is a number of physical resource blocks indicated by a resource block assignment and hopping resource allocation field.

17. The UE of claim 13 , wherein the processing circuitry further is configured to:

communicate D2D resource allocation information corresponding to the D2D data to be transmitted to the one or more UEs using a D2D control channel before transmitting D2D data,

wherein the D2D resource allocation information includes at least one of

modulation and coding scheme information,

time and frequency physical resources for D2D transmission, and

a transmission channel identity.

18. The UE of claim 13 , wherein D2D signals and conventional UL signals are transmitted in a time-division multiplexing manner, the D2D signals comprising the D2D data.

19. A user equipment (UE) configured for D2D communication, the UE comprising:

a processing circuitry configured to:

receive configuration of one or more pools of D2D communication resources by an enhanced Node B (eNB) through a common broadcast channel;

choose from the one or more pools of D2D communication resource, one or more D2D resources for D2D transmissions;

communicate D2D resource allocation information to one or more UEs; and

transmit D2D data to the one or more UEs when the D2D resource allocation information is received from the eNB,

wherein a format for communicating the D2D resource allocation information includes an indication of time/frequency physical resources for D2D data transmission and an identification of transmission channel identity for D2D control channel transmission, and

wherein, when the UE is within a network coverage, the D2D data is transmitted using at least one of timing and frequency of a serving cell's uplink transmission,

wherein a first UE of the one or more UEs to functions as a relay for D2D synchronization transmission, configuration transmission, D2D control channel transmission and reception, and D2D data channel transmission and reception with another of the one or more UEs that is not within the network coverage.

20. The UE of claim 19 , wherein the UE performs channel listening before choosing a resource for D2D transmission.

21. The UE of claim 19 , wherein the processing circuitry further is configured to:

communicate D2D resource allocation information corresponding to the D2D data to be transmitted to the one or more UEs using a D2D control channel before transmitting D2D data,

wherein the D2D resource allocation information includes at least one of modulation and coding scheme information, time and frequency physical resources for D2D transmission and a transmission channel identity.

22. The UE of claim 19 , wherein D2D signals and conventional UL signals are transmitted in a time-division multiplexing manner, the D2D signals comprising the D2D data.

23. An enhanced Node B (eNodeB), comprising:

a processing circuitry configured to:

configure one or more pools of Device-to-Device (D2D) communication resources;

signal information regarding the configured one or more pools of D2D communication resources to a first User Equipment (UE) and a plurality of UEs using a common broadcast channel;

receive a request for one or more D2D communication resources by the first UE configured to transmit D2D messages;

determine one or multiple resources for D2D communication for the first UE;

communicate D2D resource allocation information to the first UE,

wherein the first UE transmits D2D data to one or more of the plurality of UEs using the D2D resource allocation information when the D2D resource allocation information is received from the eNB,

wherein a format for communicating the D2D resource allocation information includes an indication of time/frequency physical resources for D2D data transmission and an identification of transmission channel identity for D2D control channel transmission,

wherein, when the first UE is within a network coverage, D2D signals are transmitted using at least one of timing and frequency of a serving cell's uplink transmission, and

wherein the first UE is configured to function as a relay for D2D synchronization transmission, configuration transmission, D2D control channel transmission and reception, and D2D data channel transmission and reception with another of the plurality of UEs that is not within the network coverage.

24. The eNB of claim 23 , wherein a request for the one or more D2D communication resources is received using one of; a random access procedure, or a scheduling request message, or a higher layer message,

wherein for random access procedure, D2D resource request information is received in a Message 3 of the random access procedure,

wherein the D2D resource request information includes a priority of request, an amount of resources required, and a required length of resource reservation period.

25. The eNB of claim 23 , wherein D2D resource allocation information is transmitted to the first UE using one of: a higher layer message or a layer 1 control signaling,

wherein the format is a Downlink Control Information (DCI) format,

wherein the layer 1 control signaling is carried by a Physical Downlink Control Channel (PDCCH) with the DCI format, and

wherein the DCI format is DCI format 0.