EPDCCH Resource Determination for UE Blind Decoding Reduction
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Solution Overview
Problem
The existing technologies for Enhanced Physical Downlink Control Channel (EPDCCH) in LTE face challenges in balancing the number of candidates that need to be decoded by the User Equipment (UE) and the scheduling flexibility of the eNB, leading to increased UE processing power and complexity.
Innovation Solution
Defining rules for determining the start index and gap between units of EPDCCH resources, specifically through equations for ECCE and EREG indices, to reduce the number of blind decodings and enhance scheduling flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of blind decoding candidates is increased to improve scheduling flexibility, then the eNB can select more resource configurations, but the UE processing power and complexity increase significantly
Solution Approach 1:
The search space is segmented into multiple EPDCCH sets, each with specific aggregation levels and candidate numbers. This segmentation allows the UE to process candidates in organized groups rather than as a single large set, reducing processing complexity while preserving scheduling flexibility through the structured division of search candidates across multiple sets with different aggregation levels (AL1, AL2, AL4, AL8, AL16).
Solution Approach 2:
The patent applies parameter changes by configuring different aggregation levels (AL1, AL2, AL4, AL8, AL16) and different numbers of candidates per set. The eNB can dynamically adjust these parameters based on channel conditions and scheduling requirements, optimizing the balance between scheduling flexibility and UE processing complexity without requiring the UE to handle all possible candidates uniformly.
2Device complexity
If the number of blind decodings is reduced to decrease UE processing complexity, then the UE complexity decreases, but the scheduling flexibility of the eNB is reduced
Solution Approach 1:
The patent implements dynamic configuration of search spaces where the eNB can adaptively adjust the number of candidates, aggregation levels, and EPDCCH set configurations based on current channel conditions, traffic patterns, and UE capabilities. This dynamic approach allows the system to reduce UE processing complexity in good conditions while maintaining scheduling flexibility when needed, rather than using a fixed configuration that must accommodate worst-case scenarios.
Solution Approach 2:
The patent uses partial action by configuring only the necessary number of candidates at each aggregation level based on actual scheduling needs rather than exhaustively configuring all possible candidates. The eNB can limit the search space to partial sets of candidates that are sufficient for current requirements, reducing UE processing complexity while maintaining adequate scheduling flexibility for typical operating conditions.
Data Source
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AI summary
A method for determining resources to be decoded by the UE to retrieve physical downlink control channels. A method is in a UE or an eNB and comprises the following steps of: i. determining a start position of a unit of resources in one physical resource block pair; ii, determining a gap between two of the units; and iii. determining a set of units, in a given plurality of physical resource block pairs, according to said start position and said gap, as the resources to be decoded. In this way, the eNB and the UE can locate all the resources for the EPDCCH, namely the search space is determined. This aspect allows a balance between the number of blind decoding and eNB scheduling flexibility in the EPDCCH search space.