DPSK Demodulating Apparatus for Fast Propagation Path Fluctuations
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Solution Overview
Problem
Conventional wireless communication networks using Phase Shift Keying (PSK) face challenges in maintaining communication accuracy when there are fast fluctuations in the radio wave propagation path, especially in environments with moving terminals.
Innovation Solution
A demodulating apparatus that includes a reception circuit, a first demodulation circuit for DPSK, a modulation circuit, an estimation circuit, a generation circuit, a cancellation circuit, and a control circuit, which work together to estimate variations in the amplitude and phase of propagation signals and generate simulated signals to cancel interference, enabling effective demodulation even with fast propagation path fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If CPSK is used for modulation, then tolerance against interference signals and noises is improved, but communication accuracy deteriorates when there are fast fluctuations in the radio wave propagation path
Solution Approach 1:
The patent changes the modulation method from CPSK to DPSK, which modifies the fundamental parameter of phase reference. DPSK encodes information in phase differences between consecutive symbols rather than absolute phase, making it adaptive to fast propagation path fluctuations while maintaining interference tolerance through differential encoding
Solution Approach 2:
The patent introduces a dynamic adaptation mechanism where the demodulation method switches from coherent detection (CPSK) to differential detection (DPSK) based on propagation conditions. This dynamic approach allows the system to maintain communication accuracy in fast-fluctuating environments while preserving the interference tolerance benefits of phase-based modulation
2Object-affected harmful factors
If reference signals are transmitted separately for synchronization and propagation path estimation, then tolerance against inter-terminal interference signals and noises is improved, but communication procedures become complicated
Solution Approach 1:
The patent merges the functions of data transmission and propagation path estimation into a single process. By using DPSK differential detection, the system estimates propagation path variations directly from the received signal phases without requiring separate reference signal transmissions, thereby simplifying communication procedures while maintaining interference tolerance through accurate phase difference measurement
Solution Approach 2:
The received signal in DPSK serves multiple functions simultaneously: it carries information data and provides the basis for propagation path estimation. The differential phase detection mechanism universally handles both demodulation and channel characterization, eliminating the need for dedicated reference signals and reducing procedural complexity
3Reliability
If CPSK is used with reference signals for synchronization, then communication accuracy is maintained under stable conditions, but communication procedures become complicated and response to fast propagation path fluctuations is delayed
Solution Approach 1:
The patent prepares the system for fast propagation changes by using differential encoding, which inherently tracks phase variations without requiring preliminary reference signal exchanges. The differential detection mechanism is pre-configured to measure phase differences directly, enabling immediate response to propagation path fluctuations and reducing synchronization delays
Solution Approach 2:
The DPSK system maintains continuous propagation path tracking through ongoing differential phase measurements on every received symbol. This continuous action eliminates the periodic synchronization interruptions inherent in CPSK with reference signals, ensuring uninterrupted communication accuracy even during fast propagation path transitions
Data Source
AI summary
The demodulating apparatus includes circuits of receiving modulated radio signals coming from a plurality of transmission devices, first demodulating a first reception signal DPSK-modulated among the radio signals, modulating demodulation signals into modulation signals based on DPSK, estimating an amplitude and a phase of a propagation signal on a propagation path leading to the reception circuit from the transmission device on the basis of the radio signal and the modulation signal, first generating, based on the variables, a first simulated signal simulating the first reception signal from the modulation signal, extracting a signal obtained by cancelling the first simulated signal from the radio signals, and repeating processes of the first demodulating, the modulating, the estimating, the first generating and the extracting to such a limit as to enable the first demodulating.