32 QAM Modulator Bit Segmentation for Power Reduction
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Solution Overview
Problem
In communication systems using 32 QAM, the allocation of five bits to each symbol leads to high power consumption due to the use of coding schemes with high error correction capabilities, especially when iterative processing with soft decision information is required, as errors tend to occur more frequently in the least significant bits.
Innovation Solution
A communication system is designed with a modulator that maps each symbol to specific 32 QAM signal points, using a first coding scheme for data and a second coding scheme specifically for the least significant bit, reducing power consumption by limiting high correction capability coding to only the bit most prone to errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coding scheme with high error correction capability is used for all bits in 32 QAM, then data reliability is improved, but power consumption increases significantly
Solution Approach 1:
The patent segments the five bits allocated to each 32 QAM symbol into two groups: the least significant bit (LSB) which is more prone to errors, and the other four bits. Different coding schemes are applied to each segment - a high correction capability scheme for the LSB and a simpler scheme for the remaining bits. This segmentation allows targeted error correction where needed while avoiding unnecessary power consumption for bits that don't require it.
Solution Approach 2:
The patent applies the principle of local quality by using different coding schemes with different error correction capabilities for different bit positions. Specifically, the LSB position receives enhanced error correction treatment while other positions use standard coding. This localized approach to error correction optimizes the balance between reliability and power consumption by concentrating resources where they are most needed.
2Productivity
If the number of bits allocated to each symbol is increased to achieve 800-Gbps channel capacity, then communication capacity is improved, but error occurrence rate increases due to shorter distances between signal points
Solution Approach 1:
The patent segments the five bits of each 32 QAM symbol and applies different error correction strategies to different segments. The LSB, which is most susceptible to errors due to the crowded signal points, receives specialized error correction coding. This segmentation enables the system to maintain high communication capacity while providing targeted protection against errors in the most vulnerable bit positions.
Solution Approach 2:
The patent changes the parameter of error correction capability selectively for different bit positions. By adjusting the coding scheme parameters - using stronger correction for the LSB and standard correction for other bits - the system optimizes the trade-off between communication capacity and error rate, enabling 800-Gbps transmission while maintaining data reliability.
Data Source
AI summary
A communication device that generates a modulated signal with 32 QAM includes a modulator, a first encoder and a second encoder. The modulator generates a modulated signal by mapping each symbol in a data frame that includes transmission data, a first code, and a second code to a signal point among 32 QAM signal points. The first encoder encodes the data by using a first coding scheme to generate the first code. The second encoder encodes, by using a second coding scheme, a bit string formed from one specified bit in five bits allocated to each symbol in the data frame to generate the second code. The modulator performs mapping such that each pair of signal points adjacent to each other are arranged are different from each other in terms of a value of the one specified bit among the five bits.