Methods and devices for performing proximity discovery

1. A method for use in a first user equipment (UE), comprising:

receiving, from a base station, control information and a first resource assignment assigning a resource for uplink transmission;

transmitting, based on the control information, a discovery signal on the assigned resource for uplink transmission, the discovery signal including a first temporary UE identifier (ID) assigned to the first UE, wherein the first temporary UE ID is used to identify the first UE for device-to-device communication;

receiving, from the base station, a second temporary UE ID assigned to a second UE;

receiving, from the base station, an announcement message notifying the first UE of a second resource assignment assigning a resource for the second UE for uplink transmission;

detecting the second temporary UE ID on the assigned resource for the second UE for uplink transmission;

transmitting, to the base station, a reporting message reporting the second temporary UE ID being detected; and

performing device-to-device communication with the second UE.

2. The method of claim 1 , further comprising: before receiving the control information and the first resource assignment:

transmitting, to the base station, an indication message indicating the first UE's capability of performing proximity discovery; and

receiving, from the base station, the first temporary UE ID.

3. The method of claim 1 , wherein receiving the control information and the resource assignment comprises:

receiving, on a physical downlink control channel (PDCCH), the control information and the first resource assignment for uplink transmission.

4. The method of claim 1 , wherein receiving the control information and the first resource assignment comprises:

receiving, on a physical downlink control channel (PDCCH), a resource assignment for a physical downlink shared channel (PDSCH); and

receiving, on the PDSCH, the control information and the first resource assignment for uplink transmission.

5. The method of claim 1 , wherein transmitting the discovery signal comprises: transmitting the discovery signal on a physical uplink shared channel (PUSCH), based on the first resource assignment for uplink transmission.

6. The method of claim 5 , further comprising:

encoding the first temporary UE ID with one of a tail-biting convolutional code or a turbo code to generate the discovery signal.

7. The method of claim 1 , wherein transmitting the discovery signal comprises: transmitting the discovery signal on a physical uplink control channel (PUCCH), based on first the resource assignment for uplink transmission.

8. The method of claim 7 , further comprising:

encoding the first temporary UE ID with one of a convolutional code or a Reed-Muller code to generate the discovery signal.

9. User equipment (UE) for performing device-to-device communication, comprising:

a processor; and

a memory for storing instructions executable by the processor, wherein the processor is configured to:

receive, from a base station, control information and a first resource assignment assigning a resource for uplink transmission;

transmit, based on the control information, a discovery signal on the assigned resource for uplink transmission, the discovery signal including a temporary UE identifier (ID) assigned to the UE, wherein the temporary UE identifier ID is used to identify the UE for device-to-device communication;

receive, from the base station, a second temporary UE ID assigned to a second UE;

receive, from the base station, an announcement message notifying the UE of a second resource assignment assigning a resource for the second UE for uplink transmission;

detect the second temporary UE ID on the assigned resource for the second UE for uplink transmission;

transmit, to the base station, a reporting message reporting the second temporary UE ID being detected; and

perform device-to-device communication with the second UE.

10. A method for use in a base station, comprising:

assigning a first temporary user equipment (UE) identifier (ID) and a second temporary UE ID to a first UE and a second UE, respectively;

transmitting, to the first UE, control information and a resource assignment for uplink transmission;

transmitting, to the second UE, an announcement message to notify the second UE of the resource assignment;

receiving, from the second UE, a reporting message reporting the first temporary UE ID being detected; and

transmitting, to the first UE, the second temporary UE ID assigned to the second UE.

11. The method of claim 10 , wherein assigning the first temporary UE ID and the second temporary UE ID comprises:

receiving a first indication message from the first UE, the first indication message indicating the first UE's capability of performing device-to-device communication;

assigning, in response to receiving the first indication message, the first temporary UE ID to the first UE;

receiving a second indication message from the second UE, the second indication message indicating the second UE's capability of performing device-to-device communication; and

assigning, in response to receiving the second indication message, the second temporary UE ID to the second UE.

12. The method of claim 10 , further comprising:

receiving, from the first UE, a request for performing proximity discovery;

and

transmitting, in response to receiving the request, the control information the resource assignment for uplink transmission.

13. The method of claim 10 , further comprising:

transmitting, on a physical downlink control channel (PDCCH), the control information and the resource assignment for uplink transmission.

14. The method of claim 13 , wherein transmitting on the PDCCH the resource assignment comprises:

generating a cyclic redundancy check (CRC) code for a message including the resource assignment for uplink transmission;

scrambling the generated CRC code with a radio network temporary identifier (RNTI) assigned to the first UE; and

transmitting, on the PDCCH, the message with the scrambled CRC code appended thereto.

15. The method of claim 10 , further comprising:

transmitting, on a physical downlink control channel (PDCCH), a resource assignment for a physical downlink shared channel (PDSCH); and

transmitting, on the PDSCH, the control information and the resource assignment for uplink transmission.

16. The method of claim 10 , wherein transmitting the control information comprises: transmitting a modulation and coding scheme for a discovery signal to be transmitted by the first UE.

17. The method of claim 10 , wherein transmitting the control information comprises: transmitting a signal pattern for a discovery signal to be transmitted by the first UE.

18. The method of claim 10 , wherein transmitting to the first UE the second temporary UE ID comprises:

authenticating a relationship between the first UE and the second UE; and

upon authentication, transmitting to the first UE the second temporary UE ID assigned to the second UE.

19. A base station in a wireless network, comprising:

a processor; and

a memory storing instructions executable by the processor, wherein the processor is configured to:

assign a first temporary user equipment (UE) identifier (ID) and a second temporary UE ID to a first UE and a second UE, respectively;

transmit, to the first UE, control information and a resource assignment for uplink transmission;

transmit, to the second UE, an announcement message to notify the second UE of the resource assignment;

receive, from the second UE, a reporting message reporting the first temporary UE ID being detected; and

transmit, to the first UE, the second temporary UE ID assigned to the second UE.

20. A non-transitory computer-readable medium including instructions, executable by a processor, to cause a first user equipment (UE) to perform a method, the method comprising:

receiving, from a base station, control information and a first resource assignment assigning a resource for uplink transmission;

transmitting, based on the control information, a discovery signal on the assigned resource for uplink transmission, the discovery signal including a first temporary UE identifier (ID) assigned to the first UE, wherein the first temporary UE ID is used to identify the first UE for device-to-device communication;

receiving, from the base station, a second temporary UE ID assigned to a second UE;

receiving, from the base station, an announcement message notifying the first UE of a second resource assignment assigning a resource for the second UE for uplink transmission;

detecting the second temporary UE ID on the assigned resource for the second UE for uplink transmission;

transmitting, to the base station, a reporting message reporting the second temporary UE ID being detected; and

performing device-to-device communication with the second UE.

21. A non-transitory computer-readable medium including instructions, executable by a processor, to cause a base station to perform a method, the method comprising:

assigning a first temporary user equipment (UE) identifier (ID) and a second temporary UE ID to a first UE and a second UE, respectively;

transmitting, to the first UE, control information and a resource assignment for uplink transmission;

transmitting, to the second UE, an announcement message to notify the second UE of the resource assignment;

receiving, from the second UE, a reporting message reporting the first temporary UE ID being detected; and

transmitting, to the first UE, the second temporary UE ID assigned to the second UE.