Expanded search space for R-PDCCH in LTE-A
Certain aspects of the present disclosure provide techniques and apparatuses for providing an expanded search space for a relay-specific control channel on a backhaul link. According to certain aspects, due to inband interference, a Relay Physical Downlink Control Channel (R-PDCCH) may be signaled utilizing resources reserved for backhaul data. According to certain aspects, a two-dimensional search space may be provided for R-PDCCH. R-PDCCH may be transmitted in one of a plurality of layer-specific search spaces corresponding to one of a plurality of antenna ports. Further, in a layer-specific search space, R-PDCCH may be transmitted using at least one of multiple R-PDCCH decoding candidates from a common search space and/or a relay node-specific search space.
1. A method for wireless communications by a node, comprising:
determining, based on an identity of the node, a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
performing a search of one or more of the layer-specific search spaces for a PDCCH for the node.
2. The method of claim 1 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
3. The method of claim 1 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
4. The method of claim 1 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
5. The method of claim 1 , further comprising:
receiving a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
6. The method of claim 1 , wherein the PDCCH for the node is received utilizing a spatial division multiple access (SDMA) scheme.
7. A method for wireless communications, comprising:
determining a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
transmitting, to the node, a PDCCH in one of the layer-specific search spaces.
8. The method of claim 7 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
9. The method of claim 7 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
10. The method of claim 7 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
11. The method of claim 7 , further comprising:
transmitting a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
12. The method of claim 7 , wherein the transmitting comprises transmitting the PDCCH utilizing a spatial division multiple access (SDMA) scheme.
13. An apparatus for wireless communications, comprising:
a control module configured to determine, based on an identity of the apparatus, a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
a decode module configured to perform a search of one or more of the layer-specific search spaces for a PDCCH for the node.
14. The apparatus of claim 13 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
15. The apparatus of claim 13 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
16. The apparatus of claim 13 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
17. The apparatus of claim 13 , further comprising:
a receiver module configured to receive a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
18. The apparatus of claim 13 , wherein the PDCCH for the node is received utilizing a spatial division multiple access (SDMA) scheme.
19. An apparatus for wireless communications, comprising:
a control module configured to determine a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
a transmitter module configured to transmit, to the node, a PDCCH in one of the layer-specific search spaces.
20. The apparatus of claim 19 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
21. The apparatus of claim 19 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
22. The apparatus of claim 19 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
23. The apparatus of claim 19 , wherein the transmitter module is further configured to transmit a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
24. The apparatus of claim 19 , wherein the transmitter module is further configured to transmit the PDCCH utilizing a spatial division multiple access (SDMA) scheme.
25. An apparatus for wireless communications, comprising:
means for determining, based on an identity of the apparatus, a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
means for performing a search of one or more of the layer-specific search spaces for a PDCCH for the node.
26. The apparatus of claim 25 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
27. The apparatus of claim 25 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
28. The apparatus of claim 25 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
29. The apparatus of claim 25 , further comprising:
means for receiving a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
30. The apparatus of claim 25 , wherein the PDCCH for the node is received utilizing a spatial division multiple access (SDMA) scheme.
31. An apparatus for wireless communications, comprising:
means for determining a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
means for transmitting, to the node, a PDCCH in one of the layer-specific search spaces.
32. The apparatus of claim 31 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
33. The apparatus of claim 31 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
34. The apparatus of claim 31 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
35. The apparatus of claim 31 , further comprising:
means for transmitting a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
36. The apparatus of claim 31 , wherein the means for transmitting comprises means for transmitting the PDCCH utilizing a spatial division multiple access (SDMA) scheme.
37. A computer-program product comprising a non-transitory computer-readable medium having instructions stored thereon, the instructions executable by one or more processors in a node for:
determining, based on an identity of the node, a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
performing a search of one or more of the layer-specific search spaces for a PDCCH for the node.
38. The computer-program product of claim 37 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
39. The computer-program product of claim 37 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
40. The computer-program product of claim 37 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
41. The computer-program product of claim 37 , wherein the instructions further comprise instructions for:
receiving a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
42. The computer-program product of claim 37 , wherein the PDCCH for the node is received utilizing a spatial division multiple access (SDMA) scheme.
43. A computer-program product comprising a non-transitory computer-readable medium having instructions stored thereon, the instructions executable by one or more processors for:
determining a plurality of layer-specific search spaces corresponding to a plurality of spatial layers, wherein each layer-specific search space comprises time and frequency resources used by physical downlink control channel (PDCCH) transmission to a node on a corresponding spatial layer of the plurality of spatial layers by an antenna port associated with the spatial layer; and
transmitting, to the node, a PDCCH in one of the layer-specific search spaces.
44. The computer-program product of claim 43 , wherein each layer-specific search space corresponds to multiple PDCCH candidates from a common search space and a node-specific search space.
45. The computer-program product of claim 43 , wherein each antenna port comprises a demodulation reference signal (DM-RS) port used for PDCCH demodulation.
46. The computer-program product of claim 43 , wherein the plurality of PDCCH candidates comprise no greater than 44 decoding candidates.
47. The computer-program product of claim 43 , wherein the instructions further comprise instructions for:
transmitting a semi-static assignment of a node-specific search space comprising a plurality of physical resource blocks designated for the node.
48. The computer-program product of claim 43 , wherein the instructions for transmitting comprises instructions for transmitting the PDCCH utilizing a spatial division multiple access (SDMA) scheme.