Base Station Control Channel Allocation for UE Group Resource Limits
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Solution Overview
Problem
In mobile communication systems, when multiple mobile stations are grouped into UE groups, the use of larger CCE aggregation sizes for control channels can lead to limited resource allocation, resulting in potential transmission delays and reduced cell throughput, especially for mobile stations with good channel quality.
Innovation Solution
A radio communication base station apparatus allocates control channels to specific control channel element fields within a larger number of user equipment groups, allowing for flexible allocation of CCEs across multiple search spaces, thereby preventing resource limitations and enabling efficient transmission even for mobile stations with good channel quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If mobile stations are grouped into UE groups with limited search spaces, then the number of blind decoding operations is reduced, but resource allocation flexibility deteriorates
Solution Approach 1:
The patent divides the total CCE space into multiple search spaces (first search space and second search space) with different aggregation size configurations. Mobile stations are segmented into different groups (first UE group and second UE group), each searching in their respective search spaces. This segmentation allows reduced blind decoding for each station while maintaining overall resource allocation flexibility through the base station's ability to allocate across both search spaces.
2Reliability
If larger CCE aggregation sizes are used for control channels, then coverage for cell edge users is improved, but resource allocation efficiency deteriorates
Solution Approach 1:
The patent applies different CCE aggregation size configurations to different search spaces and UE groups. The first search space uses larger aggregation sizes (e.g., 4 or 8) optimized for cell edge users with poor channel quality, while the second search space uses smaller aggregation sizes (e.g., 1 or 2) optimized for cell center users with good channel quality. This local quality differentiation ensures each user group receives appropriate resource allocation efficiency.
3Device complexity
If search spaces are limited per UE group, then blind decoding complexity is reduced, but control information transmission capability deteriorates
Solution Approach 1:
The patent creates a multi-functional search space structure where the first search space handles control information for UE groups requiring robust coverage (cell edge), while the second search space handles control information for UE groups requiring efficient resource usage (cell center). The base station can universally allocate control channels to any UE group in either search space based on channel conditions, maintaining transmission capability while reducing individual blind decoding complexity.
Data Source
AI summary
Provided is a radio communication station device which can prevent limiting of resource allocation in a UE group. The radio communication device includes: a CCE allocation unit (104); modulation units (103-1 to 103-K); an arrangement unit (108); and a radio transmission unit (111). The CCE allocation unit (104) allocates allocation information allocated to a PDCCH which is inputted from the modulation unit (103-1 to 103-K) as follows. Among a plurality of search spaces shared by a greater number of UE groups as the CCE aggregation size of the PDCCH increases, a particular search space corresponding to the CCE aggregation size of the PDCCH and a mobile group (UE group) of the PDCCH is selected as a space to which the allocation information is to be allocated. The arrangement unit (108) arranges the allocation information in a downlink resource corresponding to the CCE of the particular search space allocated among the downlink resources secured for the PDCCH. The radio transmission unit (111) transmits an OFDM symbol having the allocation information from an antenna (112) to a mobile station.