Processing enhanced PDCCH (ePDCCH) in LTE

1. A method of wireless communication, comprising:

configuring at least one virtual cell identifier (ID) for an enhanced physical downlink control channel (ePDCCH) to be transmitted to a user equipment (UE), each virtual cell ID being separately configured from a physical cell ID of a serving cell, and the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

determining a first ePDCCH decoding candidate from a plurality of ePDCCH decoding candidates used by the UE to attempt to decode the ePDCCH in a first search space;

determining a first virtual cell ID for the first ePDCCH decoding candidate, the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE;

scrambling the ePDCCH with a scrambling sequence that is based at least in part on the first virtual cell ID; and

transmitting, to the UE, the scrambled ePDCCH using the first ePDCCH decoding candidate.

2. The method of claim 1 , further comprising frequency division multiplexing the ePDCCH with other channels.

3. The method of claim 1 , in which the configuring comprises configuring the at least one virtual cell ID to be the same as at least one virtual cell ID of a physical downlink shared channel (PDSCH).

4. The method of claim 1 , in which the configuring comprises configuring the at least one virtual cell ID separately from at least one virtual cell ID of a physical downlink shared channel (PDSCH).

5. The method of claim 1 , further comprising signaling the at least one configured virtual cell ID to the UE.

6. The method of claim 1 , further comprising associating the first virtual cell ID with transmitted reference signals.

7. The method of claim 1 , further comprising:

determining a second ePDCCH decoding candidate for the UE to attempt to decode the ePDCCH in a second search space;

determining a second virtual cell ID for the second ePDCCH decoding candidate when a plurality of virtual cell IDs are configured for the UE;

scrambling the ePDCCH with a scrambling sequence that is based at least in part on the second virtual cell ID; and

transmitting the scrambled ePDCCH using the second ePDCCH decoding candidate.

8. The method of claim 7 , further comprising associating the first ePDCCH decoding candidate with a localized ePDCCH transmission and the second ePDCCH decoding candidate with a distributed ePDCCH transmission.

9. The method of claim 7 , further comprising associating the first ePDCCH decoding candidate with a first ePDCCH resource set and the second ePDCCH decoding candidate with a second ePDCCH resource set.

10. The method of claim 7 , in which the first ePDCCH decoding candidate is transmitted from a first cell and the second ePDCCH decoding candidate is transmitted from a second cell.

11. The method of claim 1 , further comprising:

configuring a plurality of ePDCCH resource sets.

12. The method of claim 1 , in which the scrambled first ePDCCH is transmitted from a plurality of cells.

13. A method of wireless communication, comprising:

determining, at a user equipment (UE), a first set of enhanced physical downlink control channel (ePDCCH) decoding candidates to attempt to decode an ePDCCH in a first search space, the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

determining, at the UE, a first virtual cell identifier (ID) for the first set of ePDCCH decoding candidates, the first virtual cell ID being separately configured from a physical cell ID of a serving cell, and the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE; and

decoding, at the UE, the ePDCCH based at least in part on the first virtual cell ID and the determined first set of ePDCCH decoding candidates.

14. The method of claim 13 , in which the ePDCCH is scrambled based at least in part on the first virtual cell ID.

15. The method of claim 13 , in which the first virtual cell ID is the same as at least one virtual cell ID of a physical downlink shared channel (PDSCH).

16. The method of claim 13 , in which the first virtual cell ID is different from at least one virtual cell ID of a physical downlink shared channel (PDSCH).

17. The method of claim 13 , further comprising:

determining a second set of ePDCCH decoding candidates to attempt to decode the ePDCCH in a second search space;

determining a second virtual cell ID for the second set of decoding candidates; and

decoding the ePDCCH based at least in part on the second virtual cell ID and the determined second set of ePDCCH decoding candidates.

18. The method of claim 17 , in which the ePDCCH of the first set of ePDCCH decoding candidates is a localized ePDCCH transmission and the ePDCCH of the second set of ePDCCH decoding candidates is a distributed ePDCCH transmission.

19. The method of claim 17 , in which the ePDCCH of the first set of ePDCCH decoding candidates is received from a first cell and the ePDCCH of the second set of ePDCCH decoding candidates is received from a second cell.

20. The method of claim 13 , in which the ePDCCH is scrambled by the first virtual cell ID.

21. The method of claim 17 , further comprising associating the first set of ePDCCH decoding candidates with a first ePDCCH resource set and the second set of ePDCCH decoding candidates with a second ePDCCH resource set.

22. The method of claim 13 , in which the ePDCCH is received from a plurality of cells.

23. The method of claim 13 , further comprising:

receiving a configuration of a plurality of ePDCCH resource sets.

24. The method of claim 13 , further comprising:

receiving at least one configured virtual cell ID; and

determining the first virtual cell ID based at least in part on the received at least one configured virtual cell ID.

25. An apparatus for wireless communications, comprising:

means for configuring at least one virtual cell identifier (ID) for an enhanced physical downlink control channel (ePDCCH) to be transmitted to a user equipment (UE), each virtual cell ID being separately configured from a physical cell ID of a serving cell, and the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

means for determining a first ePDCCH decoding candidate from a plurality of ePDCCH decoding candidates used by the UE to attempt to decode the ePDCCH in a first search space;

means for determining a first virtual cell ID for the first ePDCCH decoding candidate, the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE;

means for scrambling the ePDCCH with a scrambling sequence that is based at least in part on the first virtual cell ID; and

means for transmitting, to the UE, the scrambled ePDCCH using the first ePDCCH decoding candidate.

26. An apparatus for wireless communications, comprising:

means for determining, at a user equipment (UE), a first set of enhanced physical downlink control channel (ePDCCH) decoding candidates to attempt to decode an ePDCCH in a first search space, the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

means for determining, at the UE, a first virtual cell identifier (ID) for the first set of ePDCCH decoding candidates, the first virtual cell ID being separately configured from a physical cell ID of a serving cell, and the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE; and

means for decoding the ePDCCH based at least in part on the first virtual cell ID and the determined first set of decoding candidates.

27. A computer program product for wireless communications, the computer program product comprising:

a non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

program code to configure at least one virtual cell identifier (ID) for an enhanced physical downlink control channel (ePDCCH) to be transmitted to a user equipment (UE), each virtual cell ID being separately configured from the physical cell ID of the serving cell, and the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

program code to determine a first ePDCCH decoding candidate from a plurality of ePDCCH decoding candidates used by the UE to attempt to decode the ePDCCH in a first search space;

program code to determine a first virtual cell ID for the first ePDCCH decoding candidate, the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE;

program code to scramble the ePDCCH with a scrambling sequence that is based at least in part on the first virtual cell ID; and

program code to transmit, to the UE, the scrambled ePDCCH using the first ePDCCH decoding candidate.

28. A computer program product for wireless communications, the computer program product comprising:

a non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

program code to determine, at a user equipment (UE), a first set of enhanced physical downlink control channel (ePDCCH) decoding candidates to attempt to decode an ePDCCH in a first search space, the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

program code to determine, at the UE, a first virtual cell identifier (ID) for the first set of ePDCCH decoding candidates, the first virtual cell ID being separately configured from a physical cell ID of a serving cell, and the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE; and

program code to decode the ePDCCH based at least in part on the first virtual cell ID and the determined first set of decoding candidates.

29. An apparatus for wireless communications, comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor being configured:

to configure at least one virtual cell identifier (ID) for an enhanced physical downlink control channel (ePDCCH) to be transmitted to a user equipment (UE), each virtual cell ID being separately configured from a physical cell ID of a serving cell, and the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

to determine a first ePDCCH decoding candidate from a plurality of ePDCCH decoding candidates used by the UE to attempt to decode the ePDCCH in a first search space;

to determine a first virtual cell ID for the first ePDCCH decoding candidate;

to scramble the ePDCCH with a scrambling sequence that is based at least in part on the first virtual cell ID, the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE; and

to transmit, to the UE, the scrambled ePDCCH using the first ePDCCH decoding candidate.

30. The apparatus of claim 29 , in which the at least one processor is further configured to frequency division multiplex the ePDCCH with other channels.

31. The apparatus of claim 29 , in which the at least one processor is further configured to configure the at least one virtual cell ID to be the same as at least one virtual cell ID of a physical downlink shared channel (PDSCH).

32. The apparatus of claim 29 , in which the at least one processor is further configured to configure the at least one virtual cell ID separately from at least one virtual cell ID of a physical downlink shared channel (PDSCH).

33. The apparatus of claim 29 , in which the at least one processor is further configured to signal the at least one configured virtual cell ID to the UE.

34. The apparatus of claim 29 , in which the at least one processor is further configured to associate the first virtual cell ID with transmitted reference signals.

35. The apparatus of claim 29 , in which the at least one processor is further configured:

to determine a second ePDCCH decoding candidate for the UE to attempt to decode the ePDCCH in a second search space;

to determine a second virtual cell ID for the second ePDCCH decoding candidate when a plurality of virtual cell IDs are configured for the UE;

to scramble the ePDCCH with a scrambling sequence that is based at least in part on the second virtual cell ID; and

to transmit the scrambled ePDCCH using the second ePDCCH decoding candidate.

36. The apparatus of claim 35 , in which the at least one processor is further configured:

to associate the first ePDCCH decoding candidate with a localized ePDCCH transmission; and

to associate the second ePDCCH decoding candidate with a distributed ePDCCH transmission.

37. The apparatus of claim 35 , in which the at least one processor is further configured:

to associate the first ePDCCH decoding candidate with a first ePDCCH resource set and to associate the second ePDCCH decoding candidate with a second ePDCCH resource set.

38. The apparatus of claim 35 , in which the first ePDCCH decoding candidate is transmitted from a first cell and the second ePDCCH decoding candidate is transmitted from a second cell.

39. The apparatus of claim 29 , in which the at least one processor is further configured:

to configure a plurality of ePDCCH resource sets.

40. The apparatus of claim 29 , in which the scrambled first ePDCCH is transmitted from a plurality of cells.

41. A user equipment (UE) configured for wireless communications, the UE comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor being configured:

to determine a first set of enhanced physical downlink control channel (ePDCCH) decoding candidates to attempt to decode an ePDCCH in a first search space, the ePDDCCH being associated with at least one ePDCCH resource set of a plurality of ePDCCH resource sets configured for the UE;

to determine a first virtual cell identifier (ID) for the first set of ePDCCH decoding candidates, the first virtual cell ID being separately configured from a physical cell ID of a serving cell, and the first virtual cell ID being associated with the at least one ePDCCH resource set of the plurality of ePDCCH resource sets configured for the UE; and

to decode the ePDCCH based at least in part on the first virtual cell ID and the determined first set of decoding candidates.

42. The UE of claim 41 , in which the ePDCCH is scrambled by the first virtual cell ID.

43. The UE of claim 41 , in which the first virtual cell ID is the same as at least one virtual cell ID of a physical downlink shared channel (PDSCH).

44. The UE of claim 41 , in which the first virtual cell ID is different from at least one virtual cell ID of a physical downlink shared channel (PDSCH).

45. The UE of claim 41 , in which the at least one processor is further configured:

to determine a second set of ePDCCH decoding candidates to attempt to decode the ePDCCH in a second search space;

to determine a second virtual cell ID for the second set of decoding candidates; and

to decode the ePDCCH based at least in part on the second virtual cell ID and the determined second set of decoding candidates.

46. The UE of claim 45 , in which the ePDCCH of the first set of ePDCCH decoding candidates is a localized ePDCCH transmission and the ePDCCH of the second set of ePDCCH decoding candidates is a distributed ePDCCH transmission.

47. The UE of claim 45 , in which the ePDCCH of the first set of ePDCCH decoding candidates is received from a first cell and the ePDCCH of the second set of ePDCCH decoding candidates is received from a second cell.

48. The UE of claim 45 , in which the ePDCCH is scrambled by the second virtual cell ID.

49. The UE of claim 45 , in which the at least one processor is further configured to associate the first set of ePDCCH decoding candidates with a first ePDCCH resource set and the second set of ePDCCH decoding candidates with a second ePDCCH resource set.

50. The UE of claim 41 , in which the ePDCCH is received from a plurality of cells.

51. The UE of claim 41 , in which the at least one processor is further configured:

to receive a configuration of a plurality of ePDCCH resource sets.

52. The UE of claim 41 , in which the at least one processor is further configured:

to receive at least one configured virtual cell ID; and

to determine the first virtual cell ID based at least in part on the received at least one configured virtual cell ID.