Downlink Control Channel REG Interleaving for Diversity
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Solution Overview
Problem
Existing methods for receiving a downlink control channel in wireless communication systems face challenges in efficiently mapping and dispersing Resource Element Groups (REGs) within Control Channel Elements (CCEs) to achieve optimal diversity and interference randomization.
Innovation Solution
The proposed method involves dispersing CCEs configuring a downlink control channel across one or more physical resources and using an interleaver to randomly disperse REGs in bundle units, either on a time axis, frequency axis, or both, to enhance diversity and channel estimation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If REGs are mapped contiguously to physical resources, then the mapping process is simple, but diversity effect is reduced
Solution Approach 1:
The control channel is segmented into multiple REGs that are distributed across different physical resources. Each REG carries a portion of the control information and is mapped to separate physical resource elements, creating spatial and frequency diversity. This segmentation allows the system to achieve both simplified processing (by maintaining regular mapping patterns) and improved reliability (through distributed placement across diverse channels).
Solution Approach 2:
The patent introduces multi-dimensional mapping where REGs are distributed across multiple dimensions including frequency, time, and spatial domains. By mapping REGs to different subcarriers, different time slots, and different antenna ports simultaneously, the system achieves diversity without complicating the fundamental mapping process. This dimensional expansion allows control information to be transmitted over diverse paths while maintaining structured mapping relationships.
2Productivity
If CCEs are concentrated on limited physical resources, then resource allocation is efficient, but interference randomization is insufficient
Solution Approach 1:
The patent applies local quality by assigning different REG bundles to different CCEs with specific mapping characteristics. Each CCE can have its REGs distributed with different patterns or to different physical resource locations, allowing localized optimization for interference randomization while maintaining overall resource allocation efficiency. This enables different parts of the control channel to be adapted to local interference conditions.
3Reliability
If REGs are dispersed across multiple physical resources, then diversity effect is increased, but channel estimation complexity increases
Solution Approach 1:
The patent employs preliminary action by pre-configuring REG bundle structures and establishing predetermined mapping relationships between REGs and physical resources. Channel estimation reference signals are pre-positioned within the REG bundle structure, allowing the receiver to perform channel estimation using known patterns and relationships. This preliminary structuring reduces the complexity of real-time channel estimation while maintaining the diversity benefits of dispersed REG mapping.
Data Source
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AI summary
A method of receiving a downlink control channel at a user equipment (UE) in a wireless communication system is disclosed. The method includes receiving information on a resource element group (REG) bundle size and information on a size of a matrix for interleaving a plurality of REGs configuring at least one control channel element (CCE) through a higher layer, determining the matrix for interleaving the plurality of REGs based on the information on the size of the matrix and the information on the REG bundle size, interleaving the plurality of REGs bundled into one or more REG bundles according to the REG bundle size using the matrix, and receiving the downlink control channel based on the plurality of interleaved REGs.