Transmitting and receiving system for improving comprehensive efficiency of M-ary position phase shift keying (MPPSK) modem

Abstract

The invention discloses a transmitting and receiving system for improving comprehensive efficiency of an M-ary position phase shift keying (MPPSK) modem. An MPPSK modulation simple expression is used as basis, FORMULA, wherein omegac is angular frequency of a modulation carrier; Tc is equal to 2Pi / omegac and serves as a carrier period; rg is more than or equal to 0 and less than 1 and is used as a sign protection interval control factor; rg and integers M, N and K form a modulation parameter for changing the bandwidth, the transmission efficiency and the demodulation performance of a signal; an emitter is modulated by radio frequency or an emission medium frequency which is as high as possible; a receiver performs impact filter demodulation by up conversion frequency or a receiving medium frequency which is as high as possible; and therefore, a K value which is reduced by the emission end is increased, and the code error rate performance is improved.

Description

technical field [0001] The invention belongs to the technical field of communication system realization and a digital communication transmission and reception system, in particular to a transceiver system for improving the comprehensive efficiency of multi-position phase-shift keying modems. Background technique [0002] For the utilization rate of transmission frequency band (expressed in bps / Hz, but strictly speaking, it should be the information rate or "net" code rate after deducting channel coding) and the utilization rate of transmission energy (usually measured by unit transmission power (W) , or equivalently evaluated by receiving signal-to-noise ratio (SNR)) is the basic key technical indicator of any information transmission system, but it is difficult to achieve both. A well-known typical example is that the spread spectrum communication system sacrifices the spectrum utilization and system simplicity in exchange for the improvement of energy utilization and anti-...

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Problems solved by technology

[0021] 2) Horizontal comparison between left and right figure 1 Each line in : When N is constant, although the larger the K is, the narrower the main lobe of the power spectrum of the signal is, but the peak value is also higher, so the power spectrum characteristics become worse

[0026] 2) With the increase of K, the amplitude of the impact gradually increases at the beginning, but as K approaches N, on the one hand, the carrier component in the modulated signal is getting smaller and smaller, which can support the basic sine wave of the amplitude impact The amplitude is also getting lower and lower. In the extreme case, when K=N, it degenerates into the classic BPSK modulation, and there will be no impact. Therefore, it is usually guaranteed that Kc will also get smaller and smaller, from figure 2 (b) and figure 2 (d) It is expected that inter-symbol interference will also increase

For the currently used digital shock filter and threshold decision demodulation method, the simulation shows that when K>4, the positive contribution to the demodulation performance decreases significantly

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