Mobile Network Control Channel Search Space Segmentation
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Solution Overview
Problem
In mobile networks like LTE, the current control channel scheme requires excessive processing complexity and signaling overhead due to limited search spaces for decoding PDCCH messages, which restricts resource allocation flexibility and can lead to channel blocking under varying conditions.
Innovation Solution
A method where a primary station configures secondary stations to search for control channels across multiple resource sets, allowing them to deduce the allocated resource location within the search space without additional signaling, thereby reducing processing complexity and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile station performs blind decoding of all possible PDCCH payloads in the CCE space, then any messages intended for the mobile station can be received, but the processing complexity becomes prohibitive
Solution Approach 1:
The CCE space is segmented into multiple search spaces (common search space and UE-specific search spaces) with different aggregation levels. The mobile station performs blind decoding only within these segmented search spaces rather than the entire CCE space, reducing processing complexity from O(N) to O(M) where M << N, while maintaining reliability through comprehensive coverage of relevant search spaces.
2Device complexity
If the search spaces are restricted to reduce processing complexity, then the processing complexity is reduced, but the availability of suitable aggregations for different conditions is limited
Solution Approach 1:
The system dynamically adjusts the aggregation level and search space configuration based on channel conditions. Under good channel conditions, lower aggregation levels (1-CCE, 2-CCE) are used with corresponding search spaces, while under bad channel conditions, higher aggregation levels (4-CCE, 8-CCE) are activated. This dynamic adaptation allows the system to maintain low processing complexity during normal operation while having the versatility to handle varying channel conditions when needed.
Solution Approach 2:
The aggregation level parameter is changed based on channel quality indicators. The system monitors channel conditions and switches between different aggregation levels (1, 2, 4, or 8 CCEs) and their corresponding search spaces, thereby changing the effective search space parameters to match current conditions without requiring the mobile station to process all possible configurations simultaneously.
3Adaptability or versatility
If multiple resource sets are configured for control channels, then resource allocation flexibility is improved, but signaling overhead increases
Solution Approach 1:
The mobile station autonomously determines the appropriate resource set and aggregation level based on pre-configured search space definitions and current channel conditions, without requiring explicit signaling for each transmission. The network only needs to configure the search spaces once, and the UE self-services by selecting appropriate resources based on aggregated CCE indices and channel quality, eliminating the need for continuous resource allocation signaling.
Data Source
AI summary
A method of communicating between a primary station and a plurality of secondary stations is described. According to one aspect, the secondary station monitors a control channel search space for a control message from a primary station intended for the communication device. According to an aspect, the control message is indicative of a resource allocated to the secondary station for communicating with the primary station and the resource corresponds to a component carrier. The secondary station determines a control channel from the control channel search space having the control message intended for the secondary station and determines, based on a presence of the control channel on a specific component carrier, the indication of a resource set from a plurality of resources sets in which the resource allocated to the secondary station is located.