Table-based resource mapping for downlink control channels in a wireless system base station
View Patent ↗A transmitter comprises resource mapping circuitry configured to map symbols from multiple control channels to transmission symbols in a base station of a wireless system. The resource mapping circuitry comprises a table-based mapper configured to receive the control channel symbols and to map those symbols to the transmission symbols utilizing at least a selected one of a plurality of tables providing respective distinct mappings between the control channel symbols and the transmission symbols. For example, each of the transmission symbols may comprise a plurality of resource groups and the tables may specify distinct mappings of the control channels symbols to resource groups for different sets of possible base station parameter values. In one embodiment, the control channels comprise a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH) of an LTE cellular system.
1. An apparatus comprising:
a transmitter comprising resource mapping circuitry configured to map symbols from multiple control channels to transmission symbols in a base station of a wireless system;
the resource mapping circuitry comprising:
a table-based mapper configured to receive the control channel symbols and to map those symbols to the transmission symbols utilizing at least a selected one of a plurality of tables providing respective distinct mappings between the control channel symbols and the transmission symbols.
2. The apparatus of claim 1 wherein the resource mapping circuitry further comprises a table generator configured to generate at least a subset of the plurality of tables providing respective distinct mappings between the control channel symbols and the transmission symbols.
3. The apparatus of claim 1 wherein the multiple control channels comprise two or more of a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH).
4. The apparatus of claim 1 wherein the transmission symbols comprise orthogonal frequency division multiplexed (OFDM) symbols.
5. The apparatus of claim 1 wherein each of the transmission symbols comprises a plurality of resource groups and the tables specify distinct mappings of symbols of the control channels to the resource groups for different sets of possible values of one or more base station parameters.
6. The apparatus of claim 1 wherein at least a subset of the tables are at least partially pre-computed.
7. The apparatus of claim 1 wherein at least a given one of the tables defines one or more areas of continuous mapping of symbols from a particular one of the control channels to resource groups of at least one of the transmission symbols.
8. The apparatus of claim 1 wherein at least a subset of the tables are pre-computed and stored for respective sets of possible values of at least one frequently-changing parameter of the base station.
9. The apparatus of claim 8 wherein the frequently-changing parameter comprises at least one of an indicator of usage of an extended cyclic prefix for one or more of the control channels, a specified number of resource groups for each of one or more of the transmission symbols, and an indicator of a number of transmission symbols utilized for mapping of at least a particular type of control channel.
10. The apparatus of claim 9 wherein the frequently-changing parameter comprises an indicator of a number of OFDM symbols utilized for PHICH mapping.
11. The apparatus of claim 1 wherein the resource mapping circuitry further comprises table selection logic configured to select a particular one of the tables responsive to a current value of at least one parameter of the base station.
12. The apparatus of claim 1 wherein the resource mapping circuitry further comprises a parameter change detector configured to detect a change in a current value of at least one parameter of the base station relative to a previous value of said at least one parameter.
13. The apparatus of claim 12 wherein the parameter change detector is operative to generate at least one output that is utilized to control updating of one or more of the tables responsive to detection of a change in a current value of at least one non-frequently-changing parameter of the base station relative to a previous value of said at least one non-frequently-changing parameter.
14. The apparatus of claim 13 wherein the non-frequently-changing parameter of the base station comprises at least one of a cell identifier and a number of downlink resources available for transmission.
15. An integrated circuit comprising the apparatus of claim 1 .
16. A base station comprising the apparatus of claim 1 .
17. The apparatus of claim 1 wherein the transmitter further comprises:
a processor; and
a memory coupled to the processor;
wherein at least a portion of the resource mapping circuitry is implemented as one or more processing modules each comprising computer program code that is stored in the memory and executed by the processor.
18. A method comprising:
obtaining a plurality of tables providing respective distinct mappings between control channel symbols and transmission symbols in a base station of a wireless system;
selecting at least a particular one of the plurality of tables; and
mapping the control channel symbols to the transmission symbols utilizing said selected at least one table,
wherein the above steps of obtaining, selecting, and mapping are performed by a processor.
19. The method of claim 18 wherein the obtaining step further comprises generating at least a subset of the plurality of tables providing respective distinct mappings between the control channel symbols and the transmission symbols.
20. The method of claim 18 wherein the selecting step further comprises selecting a particular one of the tables responsive to a current value of at least one parameter of the base station.
21. The method of claim 18 wherein the obtaining step further comprises updating one or more of the tables responsive to detection of a change in a current value of at least one parameter of the base station relative to a previous value of said at least one parameter.
22. A computer program product comprising a non-transitory computer readable storage medium having executable computer program code embodied therein, wherein the computer program code when executed in the base station of the wireless system causes the base station to perform the steps of the method of claim 18 .