Non-Coherent Modulation for Phase Noise Immunity
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Solution Overview
Problem
Wireless communication systems face challenges in high frequency spectrum bands due to increased phase noise and peak-to-average power ratio (PAPR), which degrade performance and reliability, especially when using coherent modulation techniques.
Innovation Solution
The use of non-coherent modulation techniques, such as differential phase shift keying (DPSK) and higher-order PSK modulation with single-carrier frequency domain multiplexing (SC-FDM), which mitigates the effects of phase noise and improves PAPR, allowing for increased throughput and reliability in high frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coherent modulation techniques are used in high frequency spectrum bands, then communication capacity and data rate are improved, but phase noise degrades communication reliability
Solution Approach 1:
The patent changes the modulation type parameter from coherent modulation (e.g., QAM, PSK) to non-coherent modulation (DPSK) when operating in high frequency spectrum bands. This parameter change allows the system to maintain communication capacity while becoming insensitive to phase noise, thereby resolving the contradiction between productivity and reliability in high frequency bands.
2Productivity
If higher-order QAM modulation is used with SC-FDM transmissions, then throughput is increased, but peak-to-average-power ratio deteriorates
Solution Approach 1:
The patent changes the modulation type parameter from higher-order QAM to higher-order PSK modulation in SC-FDM transmissions. This parameter change increases throughput while maintaining or improving PAPR characteristics, as PSK modulation has inherently better PAPR properties compared to QAM, resolving the contradiction between productivity and energy efficiency.
3Productivity
If higher-order QAM modulation is used with SC-FDM transmissions, then throughput is increased, but PAPR increases
Solution Approach 1:
The patent changes the modulation type parameter from higher-order QAM to higher-order PSK modulation. This parameter change achieves higher throughput while controlling PAPR, as PSK modulation schemes generate lower PAPR compared to QAM schemes of the same order, thereby resolving the contradiction between productivity and harmful factors.
4Reliability
If non-coherent modulation techniques are used in high frequency spectrum bands, then phase noise immunity is improved, but spectral efficiency may be reduced
Solution Approach 1:
The patent changes the modulation order parameter in DPSK modulation (e.g., from 2-DPSK to 4-DPSK to 8-DPSK). This parameter change increases spectral efficiency while maintaining phase noise immunity, as higher-order DPSK schemes carry more bits per symbol without requiring coherent detection, resolving the contradiction between reliability and productivity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A non-coherent modulation configuration may be selected for a transmission of a set of data based on a radio frequency spectrum band used for the transmission. After selecting the non-coherent modulation configuration, the set of data may be modulated using a differential phase shift keying modulation technique. After selecting the non-coherent modulation configuration, a set of frequency-domain symbols may be generated from the set of modulated symbols using a discrete Fourier transform. The set of frequency-domain symbols may be mapped to a set of subcarriers, and a time-domain waveform may be generated from the mapped set of frequency-domain symbols, yielding a time-domain waveform. The time-domain waveform may be transmitted over the radio frequency band.