Reducing blind decoding in enhanced carrier aggregation
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may be configured with a carrier aggregation (CA) configuration, which may include a large number of component carriers (CCs). Some of the CCs may be designated as basis CCs, and may have a flexible control channel configuration, while other CCs may be designated as supplemental CCs with a restricted control channel configuration. The restricted control channels may have a reduced number of decoding candidates, which may reduce the complexity and increase the likelihood of successfully decoding the control channels. For example, the restricted control channels may be limited to a subset of aggregation levels, a reduced control region, or other restrictions. In some cases, the CCs may be grouped into basis CCs and supplemental CCs based on physical uplink control channel (PUCCH) groups or based on CCs that utilize enhanced physical downlink control channels (ePDCCH).
1. A method of wireless communication, comprising:
receiving a carrier aggregation (CA) configuration comprising one or more first component carriers (CCs) associated with a first control channel restriction and one or more second CCs associated with a second control channel restriction different from the first control channel restriction, wherein the first control channel restriction or the second control channel restriction, or both, comprises a decoding candidate restriction;
monitoring a control channel of the one or more first CCs according to the first control channel restriction; and
monitoring a control channel of the one or more second CCs according to the second control channel restriction.
2. The method of claim 1 , wherein the first control channel restriction or the second control channel restriction, or both, comprises a limited number of aggregation levels, a limited set of control information formats, a channel state information (CSI) limitation, a control region limitation, a downlink (DL) transmission mode limitation, or an uplink (UL) transmission mode limitation, or any combination thereof.
3. The method of claim 1 , wherein monitoring the control channel of the one or more first CCs comprises:
blindly decoding a first number of control message candidates for the one or more first CCs; and
monitoring the control channel of the one or more second CCs comprises blindly decoding a second number of control message candidates for the one or more second CCs, wherein the second number is less than the first number based at least in part on the first and second control channel restriction.
4. The method of claim 1 , wherein the one or more first CCs are associated with a physical downlink control channel (PDCCH) configuration and the one or more second CCs are associated with one of a PDCCH configuration or an enhanced physical downlink control channel (ePDCCH) configuration.
5. The method of claim 4 , wherein the one or more first CCs and the second CCs are grouped based at least in part on a limitation on a number of ePDCCH CCs.
6. The method of claim 4 , further comprising:
decoding a control message based at least in part on monitoring the control channel of the one or more first CCs, wherein the second control channel restriction is based at least in part on the control message.
7. The method of claim 4 , further comprising:
decoding a control message prior to monitoring the control channel for the one or more second CCs, wherein the second control channel restriction is based at least in part on the control message.
8. The method of claim 1 , further comprising:
decoding a control message based at least in part on monitoring the control channel for the one or more second CCs, wherein the control message comprises a virtual cyclic redundancy check (CRC) based at least in part on a restricted data allocation within a data field.
9. The method of claim 1 , wherein the second control channel restriction is based at least in part on a CA configuration comprising more than five CCs.
10. The method of claim 1 , further comprising:
receiving a plurality of control messages associated with a plurality of CCs of the CA configuration;
decoding downlink control information (DCI) from the plurality of control messages, wherein the DCI comprises a physical uplink control channel (PUCCH) format indication; and
transmitting a control message corresponding to at least one of the plurality of CCs according to the PUCCH format indication.
11. The method of claim 10 , wherein the PUCCH format indication is based at least in part on the plurality of CCs comprising more than five CCs.
12. A method of wireless communication, comprising:
configuring a wireless device with a carrier aggregation CA configuration comprising one or more first component carriers CCs associated with a first control channel restriction and one or more second CCs associated with a second control channel restriction different from the first control channel restriction, wherein the first control channel restriction or the second control channel restriction, or both, comprises a decoding candidate restriction;
transmitting a control channel of the one or more first CCs according to the first control channel restriction; and
transmitting a control channel of the one or more second CCs according to the second control channel restriction.
13. The method of claim 12 , wherein the first control channel restriction or the second control channel restriction, or both, comprises a limited number of aggregation levels, a limited set of control information formats, a CSI limitation, a control region limitation, a DL transmission mode limitation, or an uplink (UL) transmission mode limitation, or any combination thereof.
14. The method of claim 12 , wherein the one or more first CCs are associated with a PDCCH configuration and the one or more second CCs are associated with one of a PDCCH or an ePDCCH configuration.
15. The method of claim 12 , wherein the one or more first CCs and the second CCs are grouped based at least in part on a limitation on a number of ePDCCH CCs.
16. An apparatus for wireless communication, comprising:
a processor;
memory in electronic communication with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
receive a carrier aggregation (CA) configuration comprising one or more first component carriers CCs associated with a first control channel restriction and one or more second CCs associated with a second control channel restriction different from the first control channel restriction, wherein the first control channel restriction or the second control channel restriction, or both, comprises a decoding candidate restriction;
monitor a control channel of the one or more first CCs according to the first control channel restriction; and
monitor a control channel of the one or more second CCs according to the second control channel restriction.
17. The apparatus of claim 16 , wherein the first control channel restriction or the second control channel restriction, or both, comprises a limited number of aggregation levels, a limited set of control information formats, a channel state information (CSI) limitation, a control region limitation, a downlink (DL) transmission mode limitation, or an uplink (UL) transmission mode limitation, or any combination thereof.
18. The apparatus of claim 16 , wherein the instructions are operable to cause the apparatus to:
blindly decode a first number of control message candidates for the one or more first CCs; and
blindly decode a second number of control message candidates for the one or more second CCs, wherein the second number is less than the first number based at least in part on the first and second control channel restriction.
19. The apparatus of claim 16 , wherein the one or more first CCs are associated with a physical downlink control channel (PDCCH) configuration and the one or more second CCs are associated with one of a PDCCH configuration or an enhanced physical downlink control channel (ePDCCH) configuration.
20. The apparatus of claim 19 , wherein the one or more first CCs and the second CCs are grouped based at least in part on a limitation on a number of ePDCCH CCs.
21. The apparatus of claim 19 , wherein the instructions are operable to cause the apparatus to:
decode a control message based at least in part on monitoring the control channel of the one or more first CCs, wherein the second control channel restriction is based at least in part on the control message.
22. The apparatus of claim 19 , wherein the instructions are operable to cause the apparatus to:
decode a control message prior to monitoring the control channel for the one or more second CCs, wherein the second control channel restriction is based at least in part on the control message.
23. The apparatus of claim 16 , wherein the instructions are operable to cause the apparatus to:
decode a control message based at least in part on monitoring the control channel for the one or more second CCs, wherein the control message comprises a virtual cyclic redundancy check (CRC) based at least in part on a restricted data allocation within a data field.
24. The apparatus of claim 16 , wherein the second control channel restriction is based at least in part on a CA configuration comprising more than five CCs.
25. The apparatus of claim 16 , wherein the instructions are operable to cause the apparatus to:
receive a plurality of control messages associated with a plurality of CCs of the CA configuration;
decode downlink control information (DCI) from the plurality of control messages, wherein the DCI comprises a physical uplink control channel (PUCCH) format indication; and
transmit a control message corresponding to at least one of the plurality of CCs according to the PUCCH format indication.
26. The apparatus of claim 25 , wherein the PUCCH format indication is based at least in part on the plurality of CCs comprising more than five CCs.
27. An apparatus for wireless communication, comprising:
a processor;
memory in electronic communication with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
configure a wireless device with a carrier aggregation CA configuration comprising one or more first component carriers CCs associated with a first control channel restriction and one or more second CCs associated with a second control channel restriction different from the first control channel restriction, wherein the first control channel restriction or the second control channel restriction, or both, comprises a decoding candidate restriction;
transmit a control channel of the one or more first CCs according to the first control channel restriction; and
transmit a control channel of the one or more second CCs according to the second control channel restriction.
28. The apparatus of claim 27 , wherein the first control channel restriction or the second control channel restriction, or both, comprises a limited number of aggregation levels, a limited set of control information formats, a CSI limitation, a control region limitation, a DL transmission mode limitation, or an uplink (UL) transmission mode limitation, or any combination thereof.
29. The apparatus of claim 27 , wherein the one or more first CCs are associated with a PDCCH configuration and the one or more second CCs are associated with one of a PDCCH or an ePDCCH configuration.
30. The apparatus of claim 27 , wherein the instructions are operable to cause the apparatus to:
transmit a control message based at least in part on the second control channel restriction, wherein the control message comprises a virtual CRC based at least in part on a restricted data allocation within a data field.