Cell ID and antenna port configurations for EPDCCH

1. A method of wireless communication, comprising:

determining whether a first set of resource elements for a first reference signal, for at least a first user equipment (UE), of a first enhanced physical downlink control channel (EPDCCH) and a second set of resource elements for a second reference signal, for at least a second UE, of a second EPDCCH are selected from a same plurality of resource elements, and in which the first reference signal and the second reference signal are transmitted from a same set of antenna ports;

determining a cell identification (ID) for scrambling the first reference signal and for scrambling the second reference signal when the first set of resource elements and the second set of resource elements are selected from the same plurality of resource elements, the first set of resource elements being different from the second set of resource elements; and

transmitting the first EPDCCH and the second EPDCCH.

2. The method of claim 1 , in which the cell ID is a physical cell ID.

3. The method of claim 1 , in which the cell ID is a virtual cell ID.

4. The method of claim 1 , in which the first EPDCCH is a distributed EPDCCH and the second EPDCCH is a localized EPDCCH.

5. The method of claim 1 , in which both the first EPDCCH and the second EPDCCH are distributed EPDCCH.

6. The method of claim 1 , in which the first EPDCCH is a unicast EPDCCH and the second EPDCCH is a broadcast EPDCCH.

7. The method of claim 1 , in which the first EPDCCH is from a common search space and the second EPDCCH is from a user equipment-specific search space.

8. 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 determine whether a first set of resource elements for a first reference signal, for at least a first user equipment (UE), of a first enhanced physical downlink control channel (EPDCCH) and a second set of resource elements for a second reference signal, for at least a second UE, of a second EPDCCH are selected from a same plurality of resource elements, and in which the first reference signal and the second reference signal are transmitted from a same set of antenna ports;

to determine a first cell identification (ID) for scrambling the first reference signal and for scrambling the second reference signal when the first set of resource elements and the second set of resource elements are selected from the same plurality of resource elements, the first set of resource elements being different from the second set of resource elements; and

to transmit the first EPDCCH and the second EPDCCH.

9. The apparatus of claim 8 , in which the first cell ID is a physical cell ID.

10. The apparatus of claim 8 , in which the first cell ID is a first virtual cell ID.

11. The apparatus of claim 8 , in which the first EPDCCH is a distributed EPDCCH and the second EPDCCH is a localized EPDCCH.

12. The apparatus of claim 8 , in which both the first EPDCCH and the second EPDCCH are distributed EPDCCH.

13. The apparatus of claim 8 , in which the first EPDCCH is a unicast EPDCCH and the second EPDCCH is a broadcast EPDCCH.

14. The apparatus of claim 8 , in which the first EPDCCH is from a common search space and the second EPDCCH is from a user equipment-specific search space.

15. An apparatus for wireless communications, comprising:

means for determining whether a first set of resource elements for a first reference signal, for at least a first user equipment (UE), of a first enhanced physical downlink control channel (EPDCCH) and a second set of resource elements for a second reference signal, for at least a second UE, of a second EPDCCH are selected from a same plurality of resource elements, and in which the first reference signal and the second reference signal are transmitted from a same set of antenna ports;

means for determining a cell identification (ID) for scrambling the first reference signal and for scrambling the second reference signal when the first set of resource elements and the second set of resource elements are selected from the same plurality of resource elements, the first set of resource elements being different from the second set of resource elements;

means for processing the first reference signal and the second reference signal based on the cell ID for scrambling; and

means for transmitting the first EPDCCH and the second EPDCCH.

16. 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 whether a first set of resource elements for a first reference signal, for at least a first user equipment (UE), of a first enhanced physical downlink control channel (EPDCCH) and a second set of resource elements for a second reference signal, for at least a second UE, of a second EPDCCH are selected from a same plurality of resource elements, and in which the first reference signal and the second reference signal are transmitted from a same set of antenna ports;

program code to determine a cell identification (ID) for scrambling the first reference signal and for scrambling the second reference signal when the first set of resource elements and the second set of resource elements are selected from the same plurality of resource elements, the first set of resource elements being different from the second set of resource elements; and

program code to transmit the first EPDCCH and the second EPDCCH.