Research Of Diversity Technology Based On Phase-inversion Symmetric Modulation

A substantial increase in the speed of wireless communication promotes the development of modern diversity techniques, but channel utilization rate and the SNR of the system is still not high enough which mainly due to the con-elation between each channel. According to traditional theory, the interval between the channels should be increased in the frequency domain, time domain or airspace in order to reduce the correlation between the channels, which increasing the technical difficulty.PISM (Phase-Invertion Symmetric Modulation) is an effective method, which uses the noise correlation between the adjacent channels to suppress noise, and the combination of PISM and diversity techniques (DT) can improve the SNR of the communication system without increasing the interval between the sub channels.In this paper, the diversity techniques based on PISM (PIS-DT) has been researched, and the following work has been completed:1. The adjacent channel noise in time domain, frequency domain and airspace has been test, the result shows usually the adjacent channel noise correlation coefficient p>0.8. Through the in-depth study of the correlation of adjacent channel noise, the noise database has been established, and the following conclusions have been acquired:(1) homologous noises will be correlation;(2) adjacent noise is positive correlation;(3) man-made noise is strong correlation. All above these conclusions is used to provide data support for further research.2. The basic principles of PIS-DT have been discussed, the SNR gain formula of PIS-DT is derived, which compared with stack average method and noise cancellation method to obtain the applicable scope of PIS-DT.3. This paper has demonstrated the feasibility of PIS-DT from the frequency domain, time domain, as well as airspace, respectively establish a PIS-DT of the system model in time domain, frequency and spatial, and verifies its performance through simulation and experiment.4. This paper has used PIS-DT principle carrying out simulation analysis and experiment on2FSK, through the experiments it once again demonstrated the advantages of PIS-DT in anti-noise area.