Control Channel Search Space Mapping for Blind Detection Reduction
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Solution Overview
Problem
In wireless communication systems, particularly in CDMA and its evolutions like WCDMA and 3GPP LTE, the process of identifying control channel elements (CCEs) for user equipment (UE) through blind detection introduces significant delays, increases power consumption, and requires substantial processing resources, leading to excessive hardware complexity and false detection probabilities.
Innovation Solution
Limiting the number of control channel candidates by mapping a user equipment device identifier to specific search spaces for control channel elements and identifying these search spaces from control signals, thereby reducing the number of blind decoding attempts required for reliable detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blind detection is used to identify control channel elements for user equipment, then all possible CCE combinations can be considered to ensure detection reliability, but this introduces substantial delay, increases power consumption, and requires significant processing resources
Solution Approach 1:
The patent segments the control channel elements into multiple search space sets (first search space set and second search space set) with different aggregation levels. This segmentation allows the UE to divide the blind detection process into manageable parts, checking fewer candidates in each set rather than exhaustively searching all possible CCE combinations, thereby reducing detection delay while maintaining reliability through distributed search coverage.
Solution Approach 2:
The patent establishes predetermined search space configurations and candidate sets before the actual control channel detection occurs. The search space sets are configured in advance with specific aggregation levels and candidate positions, allowing the UE to immediately begin detection without performing preliminary exhaustive searches, thus reducing detection delay while ensuring all necessary candidates are covered.
2Reliability
If blind detection considers every possible CCE and CCE combination, then detection coverage is maximized, but power consumption and processing resources increase substantially
Solution Approach 1:
The patent divides the total search space into multiple sets with different aggregation levels (e.g., first search space set with aggregation level 4, second search space set with aggregation level 8). This segmentation reduces the number of candidates the UE must check at each aggregation level compared to exhaustive blind detection, thereby reducing power consumption while maintaining comprehensive detection coverage through the distributed structure of multiple search space sets.
Solution Approach 2:
The patent implements partial action by configuring a limited number of candidate control channels in each search space set rather than requiring the UE to evaluate all possible CCE combinations. The search space configuration specifies exact candidate positions and aggregation levels, allowing the UE to perform detection on a partial but sufficient set of candidates, reducing power consumption while achieving adequate detection coverage.
3Reliability
If blind detection evaluates all possible control channel element combinations, then no control channel is missed, but hardware complexity and false detection probabilities increase excessively
Solution Approach 1:
The patent segments the blind detection process into multiple search space sets with different aggregation levels, where each set contains a predefined number of candidates. This segmentation reduces the computational burden on the UE by dividing the detection task into smaller, manageable subsets, thereby reducing hardware complexity while maintaining detection completeness through the structured coverage of multiple sets.
Solution Approach 2:
The patent performs preliminary configuration of search space sets and candidate control channels before detection, establishing the detection framework in advance. This preliminary action defines the exact candidates and aggregation levels that the UE must check, eliminating the need for complex real-time evaluation of all possible CCE combinations, thus reducing hardware complexity while ensuring comprehensive detection coverage.
Data Source
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AI summary
A method in a base unit (101, 102) for indicating control channel candidate search spaces to a remote unit (103, 110) comprises the steps of mapping the remote unit to a set of candidate control channel elements making up a control channel candidate search space for a control channel for the remote unit, selecting a control channel comprising one or more control channel elements from the set of candidate control channel elements, and communicating control information for the remote unit using the selected control channel. A base unit and device for identifying control channel candidate search spaces is also disclosed.