Hybrid Frequency-Time Domain Equalizer for Wireless Interference
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Solution Overview
Problem
Existing equalization techniques in CDMA systems, such as time-domain (TDE) and frequency-domain (FDE) equalizers, face challenges with high computational complexity, scalability, and latency, particularly in handling multipath and inter-cell interference in wireless communication systems like UMTS.
Innovation Solution
A hybrid frequency-time domain equalization technique that determines equalizer coefficients in the frequency domain and performs filtering in the time domain, combining the advantages of TDE and FDE to reduce complexity and latency while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-domain equalization (TDE) is used to achieve good equalization performance, then equalization quality is improved, but computational complexity increases
Solution Approach 1:
The equalization process is segmented into two distinct domains: frequency-domain coefficient determination and time-domain filtering. This segmentation allows each part to operate in its most efficient domain, reducing overall computational complexity while maintaining performance
Solution Approach 2:
The invention transitions between frequency and time domains by performing coefficient determination in the frequency domain and filtering in the time domain. This dimensional switching optimizes computational efficiency without sacrificing equalization quality
2Device complexity
If frequency-domain equalization (FDE) is used to reduce computational complexity, then computational complexity is reduced, but equalization performance deteriorates
Solution Approach 1:
The equalization process is segmented into two distinct domains: frequency-domain coefficient determination and time-domain filtering. This segmentation allows each part to operate in its most efficient domain, reducing overall computational complexity while maintaining performance
Solution Approach 2:
The invention transitions between frequency and time domains by performing coefficient determination in the frequency domain and filtering in the time domain. This dimensional switching optimizes computational efficiency without sacrificing equalization quality
3Reliability
If longer equalizer lengths are used to improve equalization performance, then equalization quality is improved, but latency increases
Solution Approach 1:
The equalizer length becomes a dynamic parameter that can be adaptively adjusted based on channel conditions. This allows the system to use longer equalizer lengths only when necessary for performance, reducing latency in conditions where shorter lengths suffice
Data Source
AI summary
An equalizer includes: a channel estimator configured to generate a set of time-domain channel coefficients based on a receive signal; a frequency-domain transformer configured to generate a set of frequency-domain channel coefficients based on a frequency transform of the set of time-domain channel coefficients; an equalizer coefficient generator configured to generate a set of frequency-domain equalizer coefficients based on the set of frequency-domain channel coefficients; a time-domain transformer configured to generate a set of time-domain equalizer coefficients based on a time transform of the set of frequency-domain equalizer coefficients; and a filter configured to filter the receive signal based on a filter function that is based on the set of time-domain equalizer coefficients.