Dynamic Equalizer Length Adjustment for Wireless Signal Processing
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Solution Overview
Problem
In wireless communication systems, especially CDMA cellular systems, multipath propagation causes signal fading and intersymbol interference, leading to processing complexity and increased power consumption in equalization processes, which existing technologies struggle to efficiently address without compromising performance.
Innovation Solution
A method that dynamically adjusts the equalizer length based on channel conditions, using a 'yes or no' decision for alternative lengths, focusing on estimating the channel impulse response within a specific range and sampling the signal at an integer over-sampling ratio to determine subchannels for efficient equalization, thereby reducing processing costs without significant performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a software equaliser is used to mitigate multipath effects, then signal processing performance is improved, but processing complexity and power consumption increase
Solution Approach 1:
The equaliser length is made dynamically adjustable based on channel conditions. The system transitions from a fixed equaliser length to a variable length that adapts to the actual channel characteristics, allowing the receiver to optimize between processing complexity and performance based on current signal conditions.
Solution Approach 2:
The patent changes the parameter of equaliser length from a fixed value to a variable parameter that depends on channel conditions. By modifying this key parameter dynamically, the system can reduce processing complexity when channel conditions permit shorter equalisers while maintaining performance when longer equalisers are necessary.
2Device complexity
If a fixed-length equaliser is used, then processing complexity is reduced, but performance cannot adapt to varying channel conditions
Solution Approach 1:
The equaliser length is made dynamically adjustable based on channel conditions. The system transitions from a fixed equaliser length to a variable length that adapts to the actual channel characteristics, allowing the receiver to optimize between processing complexity and performance based on current signal conditions.
3Reliability
If continuous channel estimation is performed, then equalisation performance is improved, but processing cost increases
Solution Approach 1:
The system performs channel estimation and equalisation only to the extent necessary given current channel conditions. When channel conditions indicate that a shorter equaliser length is sufficient, the system performs partial processing rather than full processing, thereby reducing processing cost while maintaining adequate performance.
Data Source
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AI summary
A method and apparatus for processing a signal in a wireless communication system. The method comprises: receiving a signal at a receiver over a wireless channel; sampling the signal to produce a plurality of signal samples; and supplying the samples to an equaliser implemented in software running on a processor of the receiver, the equaliser being configured to process the samples using at least one equaliser time period having a nominal length. The method further comprises dynamically determining one or more characteristics of the channel; in dependence on the determined channel characteristics, dynamically selecting between a first operational state of the equaliser in which the nominal length is used and a second operational state of the equaliser in which an alternative length is used in place of the nominal length; and processing the samples in the equaliser using the determined equaliser time period length.