E-PDCCH Search Space Configuration for Scheduling Flexibility
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Solution Overview
Problem
In LTE wireless communication systems, the Enhanced Physical Downlink Control Channel (E-PDCCH) faces challenges in flexibility of base station scheduling and increased possibility of E-PDCCHs from different UEs blocking each other due to variable Resource Elements (REs) and differing Downlink Control Information (DCI) formats, leading to reduced effective E-PDCCH candidates and increased complexity for User Equipment (UE) detection.
Innovation Solution
A method for configuring the E-PDCCH search space by determining parameters based on the number of REs and bits of DCI formats, allowing for different parameters for various aggregate levels and subframes, ensuring that unusable E-PDCCH candidates are reassigned to maintain a consistent total number of candidates, thereby enhancing scheduling flexibility and reducing interference between UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If E-PDCCH parameters are configured based on fixed aggregate levels, then device complexity is reduced, but scheduling flexibility is limited
Solution Approach 1:
The patent implements dynamic E-PDCCH search space configuration by allowing the number of candidates and aggregate levels to be adjusted based on available REs and DCI format requirements. The base station can dynamically configure different parameters for different subframes and UEs, transforming the static search space into a dynamic structure that adapts to changing channel conditions and scheduling needs, thereby resolving the contradiction between flexibility and complexity.
Solution Approach 2:
The patent changes key parameters of the E-PDCCH search space including the number of candidates (M(L)), aggregate levels (L), and resource block assignments based on the number of available REs and DCI format bit lengths. By making these parameters configurable rather than fixed, the system achieves scheduling flexibility while managing UE complexity through standardized configuration procedures.
2Adaptability or versatility
If multiple DCI formats are supported with varying bit lengths, then adaptability is improved, but the number of effective E-PDCCH candidates decreases
Solution Approach 1:
The patent segments the E-PDCCH candidate space by aggregate level, where different numbers of candidates are allocated to different aggregate levels (L=1, 2, 4, 8) based on the DCI format requirements. This segmentation allows the system to support multiple DCI formats with varying bit lengths while maintaining an adequate number of effective candidates at each aggregate level, resolving the contradiction between format compatibility and candidate quantity.
Solution Approach 2:
The patent introduces the aggregate level dimension to organize E-PDCCH candidates, allowing the system to support multiple DCI formats by distributing candidates across different aggregate levels rather than requiring all candidates to support all formats. This dimensional organization preserves the total number of candidates while achieving format compatibility.
3Reliability
If E-PDCCH candidates are increased to maintain detection reliability, then reliability is improved, but the likelihood of interference between UEs increases
Solution Approach 1:
The patent applies local quality by configuring E-PDCCH search spaces with different parameters for different UEs and different subframes. Each UE receives customized configuration regarding the number of candidates and aggregate levels based on its specific channel conditions and scheduling requirements. This localized configuration maintains detection reliability for each UE while reducing overall system interference by optimizing candidate distribution.
Solution Approach 2:
The patent implements feedback mechanisms where the base station monitors E-PDCCH detection performance and channel conditions, then adjusts the search space configuration parameters accordingly. This feedback-driven adaptation ensures that each UE maintains sufficient detection reliability while the base station can optimize the overall candidate distribution to minimize inter-UE interference.
Data Source
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AI summary
A method for configuring a search space of a downlink control channel is provided. The method includes determining the parameters for Enhanced Physical Downlink Control Channel (E-PDCCH) candidates of each aggregate level according to the number of Resource Elements (RE) in a subframe and/or the number of bits of Downlink Control Information (DCI) formats, when the parameters for E-PDCCH candidates of E-PDCCH search space is configured, determining, by a User Equipment (UE), the parameters for E-PDCCH candidates according to a current downlink subframe and a detected DCI format, and detecting blindly, by the UE, the E-PDCCH candidates in the E-PDCCH search space corresponding to the parameters for E-PDCCH candidates. The present invention also provides a UE and a base station. Application of the present invention can improve the flexibility of the base station scheduling, and reduce the possibility that the E-PDCCHs of different UEs block each other.