Continuous phase modulation low-complexity demodulation method based on threshold judgment

Abstract

The invention belongs to the technical field of wireless communication, and discloses a continuous phase modulation low-complexity demodulation method based on threshold judgment. The method comprisesthe following steps of (1) carrying out symbol mapping; (2) carrying out continuous phase modulation; (3) converting the modulation signal into a frequency domain signal; (4) converting the frequencydomain signal into a time domain signal; (5) sending a modulated signal; (6) receiving a signal containing noise; (7) performing multi-user separation to obtain the time domain signals of each user;and (8) carrying out the continuous phase modulation and demodulation based on a decision threshold. According to the invention, by adopting a threshold judgment-based method, calculating the phase similarity between the received signal and the local reference signal, and settting a threshold, the number of grids matched with a filter and the Viterbi decoding is reduced, the demodulation complexity can be greatly reduced, the problem that in the prior art, the demodulation complexity is too high is solved, the complexity of a receiver can be effectively reduced, and the practicability of the system is improved.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, in particular to a low-complexity demodulation method for continuous phase modulation based on threshold judgment. Background technique [0002] At present, the closest prior art: In the field of mobile communication, limited available spectrum resources and complex wireless transmission environment are two restrictive factors in the field of wireless communication. The requirements of these communication systems for modulated signals are characterized by high requirements on spectral characteristics and insensitivity to nonlinear distortion. Continuous phase modulation (Continuous Phase Modulation, CPM) signal is a general term for a type of constant envelope modulation signal, compared with multi-ary phase shift keying (M-ary Phase Shift Keying, MPSK), it occupies a narrower bandwidth and has sidelobe attenuation Faster, with better spectral efficiency and power efficiency. At ...

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Problems solved by technology

However, the shortcomings of this method are: this method cannot maintain a constant envelope signal, has high requirements on the power amplifier, and the system spectrum utilization rate and power utilization rate are low

However, this method still has disadvantages: this method can only reduce the number of matched filters, but cannot reduce the number of grid searches in Viterbi decoding, and it destroys the structure of the optimal receiver, and the system performance is poor

[0006] (1) A continuous phase multi-carrier modulation method in the prior art cannot maintain a constant envelope signal, and has high requirements for power amplifiers, and the system spectrum utilization rate and power utilization rate are low

[0007] (2) The existence of two continuous phase modulation frequency domain equalization modulation and demodulation methods in the prior art can only reduce the number of matched filters, cannot reduce the grid search number of Viterbi decoding, and destroys the structure of the optimal receiver, poor system performance

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