SC-FDMA Receiver Joint Decoding Complexity Reduction
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Solution Overview
Problem
Current wireless communication systems face a trade-off between the complexity of receivers and their performance in decoding communication signals, particularly in LTE systems, where interference cancellation methods are either complex and costly or have suboptimal performance.
Innovation Solution
A method for decoding communication signals using antenna combining and equalization, followed by inverse discrete Fourier transforms, whitening, and maximum likelihood detection, which reduces computational complexity and suppresses spatially colored noise, allowing for a balanced trade-off between receiver complexity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maximum likelihood detection (MLD) is used for decoding communication signals, then decoding performance and interference suppression are improved, but computational complexity increases exponentially with the number of modulation symbols
Solution Approach 1:
The patent segments the received signal processing into distinct stages: antenna combining/equalization stage followed by maximum likelihood detection stage. By dividing the processing chain and applying different techniques to different segments, the patent achieves good interference suppression in the first stage while limiting the complexity of MLD in the second stage to manageable levels.
Solution Approach 2:
The patent performs preliminary signal processing through antenna combining and equalization before applying maximum likelihood detection. This preliminary action pre-processes the signal to reduce interference and normalize the channel, thereby reducing the burden on the subsequent MLD stage and lowering its computational complexity requirements.
2Object-affected harmful factors
If advanced interference combating algorithms are used, then interference suppression performance is improved, but receiver complexity and cost increase
Solution Approach 1:
The patent divides interference suppression into two parts: linear interference suppression through antenna combining and equalization, followed by non-linear interference suppression through maximum likelihood detection. This segmentation allows the system to achieve good overall interference suppression while keeping each stage's complexity manageable.
Solution Approach 2:
The patent introduces an intermediate equalization stage that processes the received signal before MLD. This intermediary processing step simplifies the signal structure and reduces interference, making the subsequent MLD operation less complex while maintaining effective interference suppression.
3Device complexity
If the output of equalization is divided into several smaller parts for joint detection, then computational complexity is reduced, but error probability increases
Solution Approach 1:
The patent applies partial joint detection by selecting only certain parts of the equalized signal output for MLD rather than processing the entire output. This partial action reduces computational complexity while the patent optimizes the selection of which parts to process to minimize the increase in error probability.
Data Source
AI summary
The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate.