Interleaved Codeword Modulation for Lower-SNR Higher-Order Signaling
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Solution Overview
Problem
Higher order modulation in communications systems requires a larger signal-to-noise ratio (SNR), which increases the bit error rate, and existing methods struggle to efficiently manage this requirement.
Innovation Solution
A modulation method that maps code words into multiple sequences, where each symbol corresponds to bits from different code words, allowing for accurate demodulation by using information from one code word to decode bits from another, thereby reducing the SNR requirement. This is achieved through serial-to-parallel conversion, delay processing, and interleaving techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher order modulation is used to improve spectrum efficiency, then spectrum efficiency is improved, but signal-to-noise ratio requirement increases
Solution Approach 1:
The code word sequence is segmented into M sequences through serial-to-parallel conversion, where each sequence contains N/M bits. This segmentation allows the system to process and demodulate bits from different code words separately, improving demodulation accuracy and reducing the SNR requirement while maintaining higher order modulation for spectrum efficiency.
Solution Approach 2:
Delay processing is applied to at least one sequence in the M sequences before mapping to symbol sequence. This preliminary action ensures that bits from different code words are properly aligned and can be demodulated using information from related code words, thereby reducing the SNR requirement before the actual modulation occurs.
2Speed
If higher order modulation is used to increase transmission rate, then transmission rate is improved, but bit error rate increases
Solution Approach 1:
By segmenting the code word sequence into M sequences and mapping them to a symbol sequence where each symbol corresponds to M bits from different code words, the system enables more accurate demodulation. This segmentation approach allows the receiver to use information from one code word to demodulate bits from another code word, reducing bit error rate while maintaining high transmission rate through higher order modulation.
Solution Approach 2:
The mapping structure creates an inherent feedback mechanism where demodulation of bits from one code word provides information that aids in demodulating bits from other code words. This cross-code word information utilization improves demodulation accuracy and reduces bit error rate in higher order modulation systems.
Data Source
AI summary
Embodiments of this application provide a modulation method and apparatus. The method includes: receiving a code word sequence, where each code word includes N bits, and the code word sequence includes at least a first code word; mapping the code word sequence into M sequences, where each sequence includes N/M bits from the first code word; mapping the M sequences into a symbol sequence, where each symbol is corresponding to M bits, the M bits are respectively from the M sequences, first bits corresponding to N/M first-type symbols are from the first code word, and second bits corresponding to N/M second-type symbols are from the first code word. Thus a signal-to-noise ratio requirement during higher order modulation lowered.