Downlink control information set switching when using carrier aggregation
A method and apparatus for reconfiguring a user equipment configured for multi-carrier operation from a first downlink control information set to a second downlink control information set while carrier aggregation is being used, including receiving a physical downlink control channel with downlink control information formats containing a carrier indicator field.
1. A method performed by a user equipment (UE), the method comprising:
reconfiguring the UE, when carriers are aggregated for use by the UE, from a first downlink control information (DCI) set to a second DCI set; and
receiving, at the UE from an access device, a physical downlink control channel (PDCCH) with DCI formats containing a carrier indicator field (CIF),
wherein the first DCI set comprises a set of DCI formats having a first CIF size, and wherein the second DCI set comprises a set of DCI formats having a second, different CIF size.
2. The method of claim 1 , wherein reconfiguring comprises changing from the first CIF size to the second CIF size, and wherein the first CIF size or the second CIF size may be equal to zero.
3. The method of claim 1 , wherein at least one common DCI format size is included in both the first DCI set and the second DCI set.
4. The method of claim 1 , wherein the CIF comprises signaling bits added to at least one of the DCI formats.
5. The method of claim 1 , wherein the CIF enables signaling on the PDCCH of one carrier being aggregated to refer to radio resources of another carrier being aggregated.
6. The method of claim 5 , wherein the radio resources referred to by the signaling on the PDCCH comprise at least one of physical downlink shared channel (PDSCH) resources and physical uplink shared channel (PUSCH) resources of the another carrier.
7. The method of claim 1 , further comprising:
when a size of a DCI format in the first DCI set equals a size of a different DCI format in the second DCI set, avoiding monitoring the DCI format in the second DCI set after the reconfiguring until a radio resource control (RRC) message is received at the UE.
8. The method of claim 1 , further comprising:
when a size of a DCI format in the first DCI set equals a size of a different DCI format in the second DCI set, including additional padding bits for the DCI format in the second DCI set.
9. A user equipment (UE) comprising:
a processor configured to:
reconfigure the UE, when carriers are aggregated for use by the UE, from a first downlink control information (DCI) set to a second DCI set; and
receive, at the UE from an access device, a physical downlink control channel (PDCCH) with DCI formats containing a carrier indicator field (CIF),
wherein the first DCI set comprises a set of DCI formats having a first CIF size, and wherein the second DCI set comprises a set of DCI formats having a second, different CIF size.
10. The UE of claim 9 , wherein the reconfigure comprises changing from the first CIF size to the second CIF size, and wherein the first CIF size or the second CIF size may be equal to zero.
11. The UE of claim 9 , wherein at least one common DCI format size is included in both the first DCI set and the second DCI set.
12. The UE of claim 9 , wherein the CIF comprises signaling bits added to at least one of the DCI formats.
13. The UE of claim 9 , wherein the CIF enables signaling on the PDCCH of one carrier being aggregated to refer to radio resources of another carrier being aggregated.
14. The UE of claim 13 , wherein the radio resources referred to by the signaling on the PDCCH comprise at least one of physical downlink shared channel (PDSCH) resources and physical uplink shared channel (PUSCH) resources of the another carrier.
15. The UE of claim 9 , wherein the processor is further configured to:
when a size of a DCI format in the first DCI set equals a size of a different DCI format in the second DCI set, avoid monitoring the DCI format in the second DCI set after the reconfigure until a radio resource control (RRC) message is received.
16. The UE of claim 9 , wherein the processor is further configured to:
when a size of a DCI format in the first DCI set equals a size of a different DCI format in the second DCI set, include additional padding bits for the DCI format in the second DCI set.
17. An access device comprising:
a processor configured to:
cause reconfiguration of a user equipment (UE), when carriers are aggregated for use by the UE, from a first downlink control information (DCI) set to a second DCI set;
transmit a physical downlink control channel (PDCCH) with DCI formats containing a carrier indicator field (CIF),
wherein the first DCI set comprises a set of DCI formats having a first CIF size, and wherein the second DCI set comprises a set of DCI formats having a second, different CIF size.
18. The access device of claim 17 , wherein the CIF comprises signaling bits added to at least one of the DCI formats.
19. The access device of claim 17 , wherein the CIF enables signaling on the PDCCH of one carrier being aggregated to refer to radio resources of another carrier being aggregated.
20. The access device of claim 19 , wherein the radio resources referred to by the signaling on the PDCCH comprise at least one of physical downlink shared channel (PDSCH) resources and physical uplink shared channel (PUSCH) resources of the another carrier.
21. The access device of claim 17 , wherein the processor is further configured to add signaling bits to the CIF of one of the DCI formats for a resource grant.
22. The access device of claim 21 , wherein the signaling bits allow signaling on a PDCCH monitoring carrier to refer to resources on a different carrier.