Reducing blind decodings for communications using carrier aggregation
View Patent ↗A method and apparatus for transmitting downlink control information when carrier aggregation is being used, by determining at least one downlink control information (DCI) format for a first carrier and at least once DCI format for a second carrier; and including padding in at least one DCI format corresponding to the second carrier such that the DCI format size of the padded DCI format equals the DCI format size of a DCI format corresponding to the first carrier.
1. A method for transmitting downlink control information when carrier aggregation is being used, the method comprising:
determining at least one downlink control information (DCI) format for a first carrier and at least one format for a second carrier;
including padding in at least one DCI format corresponding to the first carrier or the second carrier such that the DCI format size of the padded DCI format equals a reference size, wherein padding is only included in DCI formats that use a compact resource allocation method; and
transmitting DCI formats that do not user the compact resource allocation method without padding.
2. The method of claim 1 , wherein the references size is the size of the DCI format size corresponding to the first carrier.
3. The method of claim 1 , wherein the at least one DCI format of the first carrier and the at least one DCI format of the second carrier correspond to different transmission modes or different carrier bandwidths.
4. The method of claim 1 , further comprising:
encoding information corresponding to the padded DCI format; and
transmitting a DCI with the encoded information to a user equipment (UE).
5. The method of claim 1 , wherein the only DCI formats in which padding is including have a type 2 resource allocation.
6. The method of claim 1 , wherein the DCI formats that use the compact resource allocation method comprise DCI formats 0, 1A, 1B, 1C, 1D, 3, and 3A, and wherein the DCI formats that are transmitted without padding comprise DCI formats 1, 2, and 2A.
7. The method of claim 5 , wherein the DCI formats that are transmitted without padding having a type 0 or a type 1 resource allocation.
8. The method of claim 1 , further comprising signaling a reference size for use in determining a number of padding bits to be used for one or more DCI formats.
9. The method of claim 8 , wherein the reference size is signaled by an indicator that indicates the reference size.
10. The method of claim 1 , further comprising determining based on a rule a reference size of each of a plurality of downlink control information (DCI) formats.
11. The method of claim 10 , wherein the rule includes selecting a reference DCI format size as being the largest DCI format size among a plurality of DCI formats for which the padding bit difference is smaller than a threshold.
12. The method of claim 11 , wherein the threshold comprises one of an absolute value of a number of bits or a relative percentage of size difference.
13. The method of claim 10 , wherein the rule is signaled by an access device.
14. An access device for transmitting downlink control information when carrier aggregation is being used, the access device comprising:
a processor configured to:
determine at least one downlink control information (DCI) format for a first carrier and at least once DCI format for a second carrier;
include padding in at least one DCI format corresponding to the first carrier or the second carrier such that the DCI format size of the padded DCI format equals a reference size, wherein the component includes padding only in DCI formats that use a compact resource allocation method; and
transmit DCI formats that do not user the compact resource allocation method without padding.
15. The access device of claim 14 , wherein the reference size is the size of DCI format size corresponding to the first carrier.
16. The access device of claim 14 , wherein the at least one DCI format of the first carrier and the at least one DCI format of the second carrier correspond to different transmission modes or different carrier bandwidths.
17. The access device of claim 14 , wherein the processor is further configured to:
encode information corresponding to the padded DCI format; and
transmit DCI with the encoded information to a user equipment (UE).
18. The access device of claim 14 , wherein the only DCI formats that use the compact resource allocation method comprise DCI formats 0, 1A, 1B, 1C, 1D, 3, and 3A.
19. The access device of claim 18 , wherein the DCI formats in which padding is included have a type 2 resource allocation, and wherein the DCI formats that do not use the compact resource allocation method have a type 0 or type 1 resource allocation.
20. The access device of claim 14 , wherein the component is further configured to apply padding to a plurality of DCI formats that use the compact resource allocation method such that DCI formats for each carrier are padded to one of two possible total lengths, with the same two possible total lengths being used across all carriers.
21. The access device of claim 14 , wherein the component is further configured to signal a reference size for use in determining of a number of padding bits to be used for one or more DCI formats.
22. The access device of claim 21 , wherein the reference size is signaled by an indicator that indicates the reference size.
23. A user equipment (UE), comprising:
a component configured to:
determine at least one downlink control information (DCI) format for a first carrier and at least one DCI format for a second carrier;
determine an amount of padding bits in at least one DCI format corresponding to the first carrier or the second carrier such that the DCI format size of the padded DCI format equals a reference size, wherein the component determines the reference size based on an implicit rule if the at least one DCI format does not use a compact resource allocation method.
24. The UE of claim 23 , wherein the reference size is the size of DCI format size corresponding to the first carrier.
25. The UE of claim 23 , wherein the at least one DCI format of the first carrier and the at least one DCI format of the second carrier correspond to different transmission modes or different carrier bandwidths.
26. The UE of claim 23 , wherein the component is further configured to:
decode DCI based on the determined padded DCI format size.
27. The UE of claim 23 , wherein the component is further configured to determine reference sizes based on rule for each of a plurality of downlink control information (DCI) formats that do not use the compact resource allocation method.
28. The UE of claim 27 , wherein the component uses the implicit rule to determine a reference size for each of the DCI formats comprising one of DCI formats 1, 2, and 2A.
29. The UE of claim 23 , wherein the implicit rule includes selecting a reference DCI format size as being the largest DCI format size among a plurality of DCI formats for which a padding bit difference is smaller than a threshold, and wherein the threshold comprises one of an absolute value of a number of bits or a relative percentage of size difference.