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 comprising:
receiving, by a first user equipment (UE) from a base station, an indication indicating a threshold for comparing values from a random number generator for transmitting device-to-device (D2D) discovery signals using a pool of discovery resources during a discovery cycle, wherein the pool of discovery resources in the discovery cycle includes N subframes, wherein N is an integer greater than or equal to 2;
generating, by the first UE, N random numbers corresponding to the N subframes from the random number generator;
determining, by the first UE, which subframes of the N subframes are used for transmitting the D2D discovery signals based on the N random numbers and the threshold; and
transmitting, by the first UE, a D2D discovery signal to a second UE in accordance to the determining.
2. The method of claim 1 , further comprising receiving, by the first UE, an indication of a length of the discovery cycle.
3. The method of claim 1 , wherein the D2D discovery signal is transmitted over at least one resource block in a set of resource blocks, and wherein the first UE is unable to receive D2D discovery signals from another UE over the set of resource blocks during a time interval in which the first UE transmits the using the pool of discovery resources during the discovery cycle.
4. The method of claim 1 , wherein the base station is an eNB.
5. The method of claim 1 , wherein the pool of discovery resources includes time domain resources.
6. The method of claim 1 , wherein the pool of discovery resources includes frequency domain resources.
7. The method of claim 1 , wherein the pool of discovery resources is associated with transmit power levels for transmitting the D2D discovery signal during the discovery cycle.
8. The method of claim 1 , wherein the indication further indicates a probability for transmitting the D2D discovery signals using the pool of discovery resources during the discovery cycle selected from a set of probabilities comprising 0.25, 0.5, and 1.
9. A first user equipment (UE) 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 cause the first UE to:
receive, from a base station, an indication indicating a threshold for comparing values from a random number generator for transmitting device-to-device (D2D) discovery signals using a pool of discovery resources during a discovery cycle, wherein the pool of discovery resources in the discovery cycle includes N subframes, wherein N is an integer greater than or equal to 2;
generate N random numbers corresponding to the N subframes from the random number generator;
determine which subframes of the N subframes are used for transmitting the D2D discovery signals based on the N random numbers and the threshold; and
transmit a D2D discovery signal to a second UE in accordance of which subframes are used for transmitting the D2D discovery signals.
10. The first UE of claim 9 , wherein the programming further includes instructions cause the first UE to receive an indication of a length of the discovery cycle.
11. The first UE of claim 9 , wherein the D2D discovery signal is transmitted over at least one resource block in a set of resource blocks, and wherein the first UE is unable to receive D2D discovery signals from another UE over the set of resource blocks during a time interval in which the first UE transmits the using the pool of discovery resources during the discovery cycle.
12. The first UE of claim 9 , wherein the base station is an eNB.
13. The first UE of claim 9 , wherein the pool of discovery resources includes time domain resources.
14. The first UE of claim 9 , wherein the pool of discovery resources includes frequency domain resources.
15. The first UE of claim 9 , wherein the pool of discovery resources is associated with transmit power levels for transmitting the D2D discovery signal during the discovery cycle.
16. A non-transitory computer readable storage medium storing instructions, that when executed by a first user equipment (UE), cause the first UE to:
receive, from a base station, an indication indicating a threshold for comparing values from a random number generator for transmitting device-to-device (D2D) discovery signals using a pool of discovery resources during a discovery cycle, wherein the pool of discovery resources in the discovery cycle includes N subframes, wherein N is an integer greater than or equal to 2;
generate N random numbers corresponding to the N subframes from the random number generator;
determine which subframes of the N subframes are used for transmitting the D2D discovery signals based on the N random numbers and the threshold; and
transmit a D2D discovery signal to a second UE in accordance to determination of which subframes are used for transmitting the D2D discovery signals.
17. The non-transitory computer readable storage medium of claim 16 , wherein the pool of discovery resources includes time domain resources.
18. The non-transitory computer readable storage medium of claim 16 , wherein the pool of discovery resources includes frequency domain resources.
19. The non-transitory computer readable storage medium of claim 16 , wherein the pool of discovery resources is associated with transmit power levels for transmitting the D2D discovery signal during the discovery cycle.
20. A method comprising:
receiving, by a first user equipment (UE) from a base station, an indication indicating a probability for transmitting device-to-device (D2D) discovery signals using a pool of discovery resources during a discovery cycle;
identifying, by the first UE based on the indication, the probability for transmitting the D2D discovery signals using the pool of discovery resources during the discovery cycle, wherein the probability for transmitting the D2D discovery signals using the pool of discovery resources during the discovery cycle is selected from a set of probabilities comprising 0.25, 0.5, and 1; and
transmitting, by the first UE, a D2D discovery signal to a second UE during the discovery cycle based on the probability for transmitting the discovery signals using the pool of discovery resources during the discovery cycle.