Receiver Design for Bandwidth Constrained Systems
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Solution Overview
Problem
Bandwidth constrained communication systems face challenges in achieving high spectral efficiency due to complex equalization structures and high power consumption, which hinder performance and capacity, especially in handling intersymbol interference.
Innovation Solution
A receiver design that combines error control coding with a pre-processing step to shorten channel response duration, using a lower complexity equalizer and iterative decoding to improve system performance and capacity, while reducing power dissipation and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex equalization structures are used to handle intersymbol interference in bandwidth constrained systems, then system performance is improved, but device complexity and power consumption increase significantly
Solution Approach 1:
The receiver is segmented into distinct functional blocks: a bandwidth constrained channel interface, an equalizer with specific structure, and an error control decoder. This segmentation allows each component to be optimized independently, with the equalizer handling intersymbol interference through a simplified structure while the error control decoder handles error correction, thereby reducing overall complexity while maintaining performance.
Solution Approach 2:
The patent changes key parameters of the equalizer structure, specifically using a simplified equalizer with fewer taps compared to traditional complex equalizers. The equalizer parameters are optimized for bandwidth constrained channels, and the use of iterative decoding with specific initialization strategies changes the convergence parameters, allowing lower complexity structures to achieve the same performance.
2Object-affected harmful factors
If complex equalization structures are used to mitigate bandwidth limitation effects, then intersymbol interference is reduced, but power consumption increases
Solution Approach 1:
The separation of equalization and error control decoding functions allows the equalizer to be simplified while maintaining its ability to mitigate intersymbol interference. The error control decoder then handles residual errors, distributing the computational burden and reducing peak power consumption compared to a single complex equalization structure.
Solution Approach 2:
The patent employs a simplified equalizer structure that consumes less power, accepting that it may require more iterations in the decoding process. This trade-off replaces a high-power, complex equalizer with a lower-power, simpler equalizer plus iterative decoding, reducing overall power consumption while maintaining performance.
3Productivity
If bandwidth constriction is applied to improve spectral efficiency, then capacity is increased, but channel response duration extends requiring longer equalization structures
Solution Approach 1:
The patent changes the equalizer structure parameters to be optimized for bandwidth constrained channels with extended impulse responses. Instead of using long equalization filters, the system uses a simplified equalizer with fewer taps combined with iterative error control decoding, changing the approach from time-domain equalization to a hybrid approach that achieves the same effect with shorter structures.
Solution Approach 2:
The system performs preliminary error control encoding at the transmitter with specific code selection and interleaving designed for bandwidth constrained channels. This preliminary protection allows the receiver to use simpler equalization structures, as the error control code provides resilience against the extended channel effects that would otherwise require complex equalization.
Data Source
AI summary
The present invention relates to a method of improving the performance in bandwidth constrained communication systems while reducing the complexity of the equalizer used for information retrieval, as well as to improving the capacity of communication systems. These properties are achieved by appropriate information encoding, prior to signal shaping before transmission, whereas the equalizer complexity is reduced by applying the intersymbol interference shortening filter prior to the information retrieving equalization. A proper combination of the recounted elements is capable of providing a qualitatively improved and previously unsuspected performance, as compared to its constituent elements.