EPDCCH Search Space Configuration for Frequency Diversity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in efficiently setting a search space for downlink control channels, particularly in achieving optimal frequency diversity and interference randomization, especially with the introduction of advanced technologies like carrier aggregation and multi-node systems.
Innovation Solution
The proposed solution involves configuring Enhanced Physical Downlink Control Channel (EPDCCH) candidates across multiple PRB pairs, using a combination of contiguous and distributed resource sets, and applying offsets between sub-search spaces to prevent overlap and optimize resource usage, thereby enhancing frequency selective diversity and interference randomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EPDCCH candidates are configured using only contiguous resource sets, then resource allocation is simple, but frequency diversity gain is reduced
Solution Approach 1:
The search space is divided into multiple sub-search spaces, each with different configuration parameters (contiguous and distributed resource sets). This segmentation allows the system to combine both contiguous and distributed resource allocation approaches, achieving frequency diversity gain while maintaining manageable configuration complexity through structured division.
Solution Approach 2:
Different portions of the search space are assigned different qualities: some sub-search spaces use contiguous resource sets for simple allocation, while others use distributed resource sets for frequency diversity. This local differentiation optimizes both reliability and complexity management in different regions of the search space.
2Productivity
If multiple sub-search spaces are configured with overlapping resources, then resource utilization is high, but interference between candidates increases
Solution Approach 1:
Offsets are applied asymmetrically to different sub-search spaces to shift their resource allocations. By configuring different offset values for different sub-search spaces, the system prevents complete overlap of resources while maintaining high overall utilization, thereby reducing interference between EPDCCH candidates.
Solution Approach 2:
The problem of resource overlap is solved by introducing an additional dimension - the offset parameter. Instead of only adjusting the number of resources in each sub-search space, the system uses offsets to shift resources in the frequency domain, allowing multiple sub-search spaces to coexist with minimal interference while maintaining high utilization.
3Reliability
If distributed mapping is used for EPDCCH, then frequency diversity is improved, but blind decoding complexity increases
Solution Approach 1:
The distributed mapping search space is segmented into multiple sub-search spaces with different configuration parameters. This segmentation reduces the number of blind decoding attempts required in each sub-search space while maintaining the overall frequency diversity benefit of distributed mapping across the entire EPDCCH search space.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
The present invention relates to a method for a terminal to receive an enhanced physical downlink control channel (EPDCCH) from a based station in a wireless communication system. In detail, the method includes the step of: receiving the EPDCCH by monitoring EPDCCH candidates consisting of one or more enhanced control channel elements (ECCEs) in at least one resource block set for EPDCCH, wherein the number of ECCEs forming each of the EPDCCH candidates corresponds to an aggregation level, and the period between the EPDCCH candidates for one carrier, which is a specific aggregation level, is determined by dividing the total number of ECCEs included in each of the one or more resource blocks by a corresponding aggregation level and the number of the EPDCCH candidates which are the specific aggregation level.