Quasi-Linear Receiver for Co-Channel Interference Cancellation
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Solution Overview
Problem
Wireless communication systems, particularly GSM/EDGE, face capacity limitations due to co-channel interference, which existing technologies have not adequately addressed, especially in mobile terminals with compact designs and cost constraints.
Innovation Solution
The implementation of an iterative quasi-linear receiver with a quasi-linear filter and slicer or maximum likelihood equalizer to cancel inter-symbol interference and co-channel interference, using filter weight estimations and channel re-estimation to enhance performance in noise-limited and interference-limited environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency reuse pattern is made more aggressive to augment throughput, then system capacity increases, but co-channel interference increases
Solution Approach 1:
The patent converts the harmful co-channel interference into a useful signal for estimation purposes. By treating the interfering signal as a known or estimable component, the receiver can subtract it from the total received signal, thereby eliminating its harmful effect while maintaining the aggressive frequency reuse pattern that enables higher system capacity
2Reliability
If multiple receive antennas are used to achieve efficient interference suppression, then interference cancellation performance improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the interference component from the received signal through estimation and subtraction, achieving interference suppression without requiring multiple antennas. This separates the interference cancellation function from the antenna array structure, allowing single-antenna implementations to achieve performance comparable to multi-antenna systems
3Measurement precision
If iterative channel re-estimation is performed to improve interference cancellation accuracy, then receiver performance improves, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary channel estimation using known training sequences before the actual data reception. This preliminary action provides an initial channel estimate that is then refined iteratively, reducing the computational burden during real-time processing while maintaining high accuracy through the iterative refinement process
Data Source
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AI summary
A method for cancellating interference from a received signal in a wireless communication system includes: processing the received signal; calculating filter weights, by a filter weights estimation module, from the received signal; generating a corrected sequence, through a widely linear-single antenna interference cancellation (WL-SAIC) module, by applying the filter weights; calculating a channel estimation concurrently with the corrected sequence; and generating an adjusted data by an output equalizer including applying the channel estimation to the corrected sequence.