Tomlinson-Harashima Precoder Eliminates Guard Intervals
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Solution Overview
Problem
Existing communication systems face inefficiencies due to the need for guard intervals, which waste bandwidth and limit spectral efficiency, as they combat intersymbol and intercarrier interference.
Innovation Solution
A precoder is introduced that uses Tomlinson-Harashima precoding to predistort symbol blocks based on channel characteristics, eliminating the need for guard intervals by removing intrasymbol and intersymbol interference, allowing for low-latency, high-data rate transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guard intervals are used to combat intersymbol interference and intercarrier interference, then transmission reliability is improved, but spectral efficiency deteriorates due to wasted bandwidth
Solution Approach 1:
The precoder applies predistortion to the transmitted signal in advance based on channel characteristics, so that the signal is already compensated for anticipated interference before transmission. This preliminary action eliminates the need for guard intervals, achieving both high reliability and high spectral efficiency by removing the wasted bandwidth while maintaining interference protection
Solution Approach 2:
The precoder generates a predistorted signal that pre-counteracts the expected intersymbol interference and intercarrier interference caused by the transmission channel. By applying this preliminary anti-action, the signal arrives at the receiver already compensated, eliminating the need for guard intervals and thereby improving spectral efficiency while maintaining transmission reliability
2Reliability
If guard intervals are used to prevent interference between blocks, then transmission reliability is improved, but transmission latency increases due to reduced data transmission time
Solution Approach 1:
The precoder applies predistortion in advance to compensate for channel effects, eliminating the need for guard intervals. This allows continuous data transmission without time-wasting guard periods, thereby reducing transmission latency while maintaining reliability through the predistortion mechanism
3Productivity
If the cyclic prefix length is reduced to improve spectral efficiency, then bandwidth utilization is improved, but intersymbol interference increases
Solution Approach 1:
The precoder applies predistortion before transmission to compensate for the effects of reduced cyclic prefix length. This preliminary compensation counteracts the potential intersymbol interference that would otherwise result from shorter guard intervals, allowing the system to achieve high spectral efficiency without suffering from increased interference
Solution Approach 2:
The precoder converts the potential harm of reduced cyclic prefix length (which would cause intersymbol interference) into a benefit by using the same short prefix length to enable higher spectral efficiency. The predistortion mechanism transforms what would be a harmful condition into an acceptable operating point that achieves both goals
Data Source
AI summary
The present invention relates to a precoder for a communication system arranged to provide transmission blocks for transmission over a transmission channel based on inputted symbol blocks. The precoder is arranged to pre-distort each symbol block based on an estimate of the characteristics of the transmission channel so that the corresponding transmission block appears to be undistorted after transmission over the transmission channel. In accordance therewith, the precoder is arranged to apply Tomlinson-Harashima precoding on a sum of a first measure corresponding to predistortion so as to remove intrasymbol interference and a second measure corresponding to predistortion so as to remove intersymbol interference. The present invention further relates to a method for providing transmission blocks for transmission over a transmission channel in a communication system.