Mapping method and apparatus for a search space of a physical downlink control channel
Embodiments of the present invention provide a mapping method and apparatus for a search space of a physical downlink control channel. The method includes: determining a search space allocated to the PDCCH according to a resource allocation scheme; and mapping each of candidates of the PDCCH to a logic time frequency resource of the search space according to a predefined interval. With the method and apparatus of the embodiments of the present invention, a frequency selective scheduling gain is obtained by mapping different candidates onto discrete time frequency resources, or a frequency diversity gain is obtained by mapping one candidate onto discrete time frequency resources, thereby improving the performance of the PDCCH.
1. A mapping method for a search space of a physical downlink control channel (PDCCH), comprising:
determining a search space allocated to the PDCCH according to a resource allocation scheme;
mapping discretely multiple candidates of the PDCCH onto time frequency resources of the search space by taking a candidate of the PDCCH as a unit according to a predefined interval, wherein different candidates of the PDCCH are mapped onto discrete time-frequency resources, and
mapping discretely multiple allocating units of a resource block (RB) contained in each candidate of the PDCCH onto time frequency resources to which the candidate of the PDCCH corresponds by taking an allocating unit of RB contained in each candidate of the PDCCH as a unit,
wherein the time frequency resources to which the candidate of the PDCCH corresponds are discrete, different allocating units of one candidate of the PDCCH are mapped onto discrete time frequency resources, and the allocation units are smaller time-frequency resource blocks obtained by dividing the RB.
2. The method according to claim 1 , wherein the predefined interval is a value that different candidates of the control channel are mapped onto resources not adjacent to each other.
3. The method according to claim 2 , wherein the predefined interval is a subband size fed back by user equipment (UE).
4. The method according to claim 2 , wherein the predefined interval is a resource block group (RBG) of user equipment (UE).
5. The method according to claim 2 , wherein when the number of the resources of the search space is less than a product of a total number of the candidates of the PDCCH and the predefined interval, part of the candidates of the PDCCH are mapped first onto time frequency resources to which each of the predefined intervals corresponds, and then the rest of the candidates are mapped in a cyclic shift scheme onto time frequency resources to which each of the predefined intervals corresponds.
6. The method according to claim 5 , wherein the method further comprises:
determining the total number of the candidates of the PDCCH according to an aggregation level.
7. The method according to claim 2 , wherein a position of each of the candidates of the PDCCH at a corresponding time frequency resource to which the predefined interval corresponds is random.
8. The method according to claim 2 , wherein the method further comprises:
transmitting an index of a corresponding allocating unit within one predefined interval to user equipment (UE).
9. A base station, applicable to mapping of a search space of a physical downlink control channel (PDCCH), wherein the base station comprises:
a first determining unit configured to determine a search space allocated to the PDCCH according to a resource allocation scheme;
a first mapping unit configured to map discretely multiple candidates of the PDCCH onto time frequency resources of the search space by taking a candidate of the PDCCH as a unit according to a predefined interval, wherein different candidates of the PDCCH are mapped onto discrete time-frequency resources, and
a second mapping unit configured to map discretely multiple allocating units of resource blocks (RBs) contained in each candidate of the PDCCH onto time frequency resources to which the candidate of the PDCCH corresponds by taking an allocating unit of RB contained in each candidate of the PDCCH as a unit,
wherein the time frequency resources to which the candidate of the PDCCH corresponds are discrete, different allocating units of one candidate of the PDCCH are mapped onto discrete time frequency resources, and the allocation units are smaller time-frequency resource blocks obtained by dividing the RB.
10. The base station according to claim 9 , wherein the predefined interval is a value that different candidates of the control channel are mapped to resources not adjacent to each other.
11. The base station according to claim 10 , wherein the predefined interval is a subband size fed back by user equipment (UE).
12. The base station according to claim 10 , wherein the predefined interval is a resource block group (RBG) of user equipment (UE).
13. The base station according to claim 10 , wherein when the number of the resources of the search space is less than a product of a total number of the candidates of the PDCCH and the predefined interval, the first mapping unit maps first part of the candidates of the PDCCH onto time frequency resources to which each of the predefined intervals corresponds, and then maps in a cyclic shift scheme the rest of the candidates onto time frequency resources to which each of the predefined intervals corresponds.
14. The base station according to claim 13 , wherein the base station further comprises:
a second determining unit configured to determine the total number of the candidates of the PDCCH according to an aggregation level.
15. The base station according to claim 10 , wherein a position of each of the candidates of the PDCCH at a corresponding time frequency resource to which the predefined interval corresponds is random.
16. The base station according to claim 10 , wherein the base station further comprises:
a transmitting unit configured to transmit an index of a corresponding allocating unit within one predefined interval to user equipment (UE).