System and method for time-power-frequency hopping for D2D discovery
A system and method for D2D discovery is provided. In an embodiment the method includes sending, by a base station, first parameters to a first User Equipment (UE) indicating a set of discovery resources in a discovery cycle, wherein the discovery cycle comprises a plurality of subframes; and sending, by the base station, second parameters to the first UE indicating a first probability for transmitting a first discovery signal to a second UE on a subframe of the plurality of subframes so that the first UE is capable of transmitting the first discovery signal to a second UE in the discovery cycle according to the first parameters when a random number between 0 and 1, selected by the first UE, is equal or larger than the first probability.
1. A method for assigning resources for a device-to-device (D2D) discovery signal, the method comprising:
sending, by a base station, first parameters to a first User Equipment (UE) indicating a set of discovery resources in a discovery cycle, wherein the discovery cycle comprises a plurality of subframes; and
sending, by the base station, second parameters to the first UE indicating a first probability for transmitting a first discovery signal to a second UE so that a transmission of a first discovery signal from the first UE to the second UE in the discovery cycle is based upon the first probability,
wherein the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon the first probability comprises:
the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon that a random number between 0 and 1 selected by the first UE is equal or larger than the first probability; or
the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon that a random number between 0 and 1 selected by the first UE is less than the first probability, and wherein the first probability is 0.25, 0.75 or 1.
2. The method according to claim 1 , wherein the random number is selected for the discovery cycle.
3. The method according to claim 1 , wherein sending the second parameters comprises sending a second probability for transmitting a second discovery signal in a further discovery cycle, wherein the first probability is different from the second probability.
4. The method according to claim 1 , further comprising sending, by the base station, a length of the discovery cycle.
5. The method according to claim 1 , wherein the subframes comprise a set of resource blocks, and wherein, when the UE transmits the first discovery signal on a selected resource block from the set of resource blocks, the UE is unable to receive a further discovery signal from another UE on other resource blocks from the set of resource blocks.
6. The method according to claim 1 , wherein the second parameters are assigned to the first UE via Radio Resource Control (RRC) signaling.
7. The method according to claim 1 , wherein the base station is an eNB.
8. The method according to claim 1 , wherein the discovery resources comprises at least one of time, frequency or power for transmitting the first discovery signal in the discovery cycle.
9. A base station comprising:
at least one processor; and
a non-transitory computer readable storage medium storing programming for execution by the at least one processor, the programming including instructions to:
send first parameters to a first User Equipment (UE) indicating a set of discovery resources in a discovery cycle, wherein the discovery cycle comprises a plurality of subframes; and
send second parameters to the first UE indicating a first probability for transmitting a first discovery signal to a second UE so that a transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon the first probability,
wherein the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon the first probability comprises:
the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon that a random number between 0 and 1 selected by the first UE is equal or larger than the first probability; or
the transmission of the first discovery signal from the first UE to the second UE in the discovery cycle is based upon that a random number between 0 and 1 selected by the first UE is less than the first probability, and
wherein the first probability is 0.25, 0.75 or 1.
10. The base station according to claim 9 , wherein the random number is selected for the discovery cycle.
11. The base station according to claim 9 , wherein the second parameters are assigned to the first UE via Radio Resource Control (RRC) signaling.
12. The base station according to claim 9 , wherein the instruction to send the second parameters comprises send a second probability for transmitting a second discovery signal in a further discovery cycle, wherein the first probability is different from the second probability.
13. The base station according to claim 9 , further comprising the instruction to send a length of the discovery cycle.
14. The base station according to claim 9 , wherein the subframes comprise a set of resource blocks, and wherein, when the UE transmits the first discovery signal on a selected resource block from the set of resource blocks, the UE is unable to receive a further discovery signal from another UE on other resource blocks from the set of resource blocks.
15. The base station according to claim 9 , wherein the discovery resources comprises at least one of time, frequency or power for transmitting the first discovery signal in the discovery cycle.
16. The base station according to claim 9 , wherein the base station is an eNB.