Search space design with overbooking in carrier aggregation

Patent metadata

Field	Value
Publication number	US-2019349155-A1
Application number	US-201916406265-A
Country	US
Kind code	A1
Filing date	May 8, 2019
Priority date	May 11, 2018
Publication date	Nov 14, 2019
Grant date	—

Abstract

Methods, systems, and devices for wireless communications are described that provide for allocation of control channel candidates for multiple component carriers (CCs) in carrier aggregation (CA) communications. A CA limit may correspond to a total number of configurable control channel candidates across multiple CCs. The control channel candidates may include blind decoding (BD) candidates or control channel element (CCE) candidates for channel estimation. A per-CC limit of control channel candidates may correspond to a number of configurable control channel candidates for each CC. An applied set of control channel candidates may be determined by allocating control channel candidates across the multiple CCs based on the CA limit and the per-CC limit. Such techniques may be used in cases where the CCs have a same numerology or mixed numerology, and may also be used for cross-carrier scheduling.

First claim

What is claimed is:

1 . A method for wireless communication, comprising:
establishing a wireless connection via a set of component carriers (CCs) using carrier aggregation (CA); determining a CA limit corresponding to a total number of configurable control channel candidates across the set of CCs, the control channel candidates including blind decoding (BD) candidates or control channel element (CCE) candidates for channel estimation; determining a per-CC limit corresponding to a per-CC number of control channel candidates that are configurable for each CC of the set of CCs; determining an applied set of control channel candidates by allocating control channel candidates across a number of configured control channel candidates of the set of CCs based at least in part on the CA limit and the per-CC limit, wherein the number of configured control channel candidates for at least one CC of the set of CCs may exceed the per-CC limit; and communicating based at least in part on the applied set of control channel candidates.

2 . The method of claim 1 , wherein the determining the applied set of control channel candidates comprises:
allocating control channel candidates separately for each CC of the set of CCs, the control channel candidates for each CC allocated to comply with the per-CC limit.

3 . The method of claim 1 , wherein a user equipment (UE) is capable of supporting a first number of CCs, and wherein a second number of CCs in the set of CCs is less than or equal to the first number of CCs, and wherein the control channel candidates for each CC are separately allocated to each comply with the per-CC limit.

4 . The method of claim 1 , wherein a user equipment (UE) is capable of supporting a first number of CCs, and wherein a second number of CCs in the set of CCs is greater than the first number of CCs.

5 . The method of claim 4 , wherein the determining the applied set of control channel candidates comprises:
selecting a subset of CCs from the set of CCs, the subset of CCs having a third number of CCs corresponding to the first number of CCs; and allocating control channel candidates across the subset of CCs, wherein the control channel candidates for each CC of the subset of CCs are separately allocated to each comply with the per-CC limit.

6 . The method of claim 4 , wherein the per-CC limit for each CC of the set of CCs is defined by a set of non-negative numbers such that the per-CC limit is a product of a selected non-negative number, the first number of CCs, and a single carrier limit of control channel candidates that are configurable for a single non-CA carrier, and wherein the selected non-negative number is based at least in part on whether a BD limit budget or a CCE limit budget is distributed evenly, proportional to a bandwidth, or proportional to configured control channel candidates, for each CC.

7 . The method of claim 4 , wherein the determining the applied set of control channel candidates comprises:
distributing a BD limit budget or a CCE limit budget evenly across the second number of CCs, wherein a portion of the BD limit budget or the CCE limit budget for each CC corresponds to a product of the first number of CCs and the per-CC limit divided by the second number of CCs.

8 . The method of claim 4 , wherein the determining the applied set of control channel candidates comprises:
distributing a BD limit budget or a CCE limit budget across the second number of CCs according to a bandwidth-proportional distribution, wherein a portion of the BD limit budget or the CCE limit budget for each CC corresponds to a product of the first number of CCs, the per-CC limit, and a bandwidth of an associated CC, divided by a total cumulative bandwidth of the second number of CCs.

9 . The method of claim 4 , wherein the determining the applied set of control channel candidates comprises:
distributing a BD limit budget or a CCE limit budget across the second number of CCs according to a slot-based proportional distribution, wherein a portion of the BD limit budget or the CCE limit budget for each CC corresponds to a product of the first number of CCs, the per-CC limit, and a number of BDs or CCEs associated with the configured control channel candidates of an associated CC for an associated slot, divided by a total cumulative number of configured control channel candidates of the second number of CCs.

10 . The method of claim 4 , wherein the determining the applied set of control channel candidates comprises:
reducing a number of CCs of the set of CCs that can be scheduled with control channel transmissions to correspond to the second number of CCs, and distributing a BD limit budget or a CCE limit budget across configured control channel candidates of the reduced number of CCs; or; and maintaining the per-CC limit for a first subset of CCs and distributing remaining of the CA limit control channel candidates among remaining CCs of the set of CCs.

11 . The method of claim 1 , wherein the determining the applied set of control channel candidates comprises:
identifying a plurality of search space (SS) sets that indicate, for each CC of the set of CCs, associated resources for available control channel candidates; and mapping the plurality of SS sets of each CC of the set of CCs up to the per-CC limit to determine the applied set of control channel candidates for a corresponding CC, wherein each CC of the set of CCs has an ordered CC index, and wherein the mapping is from a lowest CC index to a highest CC index.

12 . The method of claim 1 , wherein the determining the applied set of control channel candidates comprises:
identifying a plurality of search space (SS) sets that each indicate associated resources for available control channel candidates for two or more CCs, wherein each CC set has a SS set index; and mapping the each CC associated with each SS set from the plurality of SS sets to determine the applied set of control channel candidates for a corresponding SS set, wherein a control channel candidate for a CC is skipped if the per-CC limit for the corresponding CC is reached or the CC is fully mapped, and wherein the mapping is from a lowest SS index to a highest SS index.

13 . The method of claim 1 , wherein a user equipment (UE) is capable of supporting a first number of CCs, and wherein a second number of CCs in the set of CCs is greater than the first number of CCs, and wherein the determining the applied set of control channel candidates comprises:
allocating control channel candidates jointly for the set of CCs, the control channel candidates for each CC allocated to comply with the per-CC limit and the CA limit.

14 . The method of claim 13 , wherein the allocating the control channel candidates comprises:
identifying a plurality of search space (SS) sets that indicate, for each CC of the set of CCs, associated resources for available control channel candidates; mapping the plurality of SS sets of each CC of the set of CCs up to the per-CC limit to determine the applied set of control channel candidates for the corresponding CC, wherein each CC of the set of CCs has an ordered CC index, and wherein the mapping is from a lowest CC index to a highest CC index; maintaining a cumulative count of mapped control channel candidates across the set of CCs; and stopping the mapping if the cumulative count reaches the CA limit.

15 . The method of claim 13 , wherein the allocating the control channel candidates comprises:
identifying plurality of search space (SS) sets that each indicate associated resources for available control channel candidates for two or

Assignees

• Qualcomm Inc

Inventors

• Xu Huilin
• Lee Heechoon
• Sun Jing
• Ang Peter Pui Lok
• Chen Wanshi
• Soriaga Joseph Binamira
• Gaal Peter
• Luo Tao

Classifications

• H04L5/0053

  Allocation of signalling, i.e. of overhead other than pilot signals · CPC title

• H04L5/001 Primary

  the frequencies being arranged in component carriers · CPC title

• H04L5/0042 Primary

  Intra-user or intra-terminal allocation · CPC title

• H04L27/26025 Primary

  Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking (allocating sub-channels of the transmission path H04L5/003) · CPC title