Dual MMSE Equalization for Multi-Cluster Delay Path Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, especially CDMA, the existing equalization techniques fail to effectively mitigate interference from multiple clusters of delay paths in frequency-selective channels, leading to degraded receiver performance due to insufficient window length and error propagation.
Innovation Solution
The use of two equalizers, each calculated based on minimum mean square error (MMSE) criterion for separate clusters of delay paths, to equalize received signals and reduce interference, with weights calculated using channel gains from both clusters to combine signals and improve demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the window length of the equalizer is set to F=2L based on conventional equalization techniques, then the equalizer can effectively eliminate interference for single-cluster channels, but it becomes insufficient for channels with multiple clusters and large delay spreads, leading to degraded receiver performance
Solution Approach 1:
The patent divides the equalizer into multiple separate equalizers, each dedicated to a specific cluster. Instead of using a single equalizer with window length F=2L that cannot effectively handle multiple clusters, the system creates separate equalizers for each cluster, allowing each to be optimized for its specific delay spread characteristics while collectively handling the entire multi-cluster channel.
2Device complexity
If a single equalizer with fixed window length F=2L is used, then the hardware implementation is simple, but it cannot sufficiently process interferences from different clusters in channels with large delay spreads
Solution Approach 1:
The patent segments the single equalizer into multiple separate equalizers, each handling a specific cluster. This segmentation increases structural complexity but dramatically improves interference cancellation effectiveness by allowing each equalizer to be specifically tuned to its cluster's characteristics rather than trying to handle all clusters with a fixed window length.
Solution Approach 2:
Each equalizer is designed with local quality optimized for its specific cluster's delay spread characteristics. Instead of using a uniform window length F=2L for all clusters, each equalizer can have different parameters and characteristics matched to its specific cluster, improving overall interference cancellation while maintaining reasonable hardware complexity.
Data Source
AI summary
This invention relates to an equalization apparatus, an equalization method and a receiver using the same. Two equalizers are applied to the equalization apparatus to cover two clusters of a channel. The weights of the two equalizers are calculated by channel gains of the whole channel based on the minimum mean square error criterion. Therefore the interference of the whole channel due to different clusters can be reduced enormously.