| In wireless communication,Relay system can satisfy a large number of users to share a certain number of channels in one area.Most existing relay system use the traditional digital transmission scheme,so the existence of the digital transmission scheme can not avoid cliff effect and saturation effect,in order to reduce the traditional digital solutions of cliff effect and the influence of saturation effect,this paper studies the Hybrid digital-and-analog transmission(Hybrid digital analog,HDA)applied to relay system,and from the adaptive power allocation algorithm to make optimization framework.Firstly,the Recursive distortion estimation of Hybrid digital analog based on Relay(RRDEHDA)in the Relay system is proposed.Firstly,the video sequence is encoded by h.264/AVC to obtain the two-level bitstream.Then FEC(Forward error correction)and channel modulation are carried out on the bitstream.Get the digital transmission signal;The quantized residuals were coded by softcast to get the analog signals.Finally,the mixed signals were sent to Rayleigh channel,and the expected distortion of the system was estimated by channel state information.Experiments show that the video quality obtained by mixed digital analog transmission in the relay system is better than that obtained by pure digital transmission.Second,in the R-RDEHDA system,power distribution and affects the interrupt probability of relay system(Outage aim-listed probability),and the result of the hybrid digital analog transmission,so this paper proposes a relay transmission system based on hybrid digital analog transmission adaptive power allocation scheme,make the system can get the best transmission in different channel environment performance.Experimental results show that the performance of the recursive distortion estimation scheme based on mixed digital analog video transmission is optimized by 5db-9db compared with the relay system without adaptive power allocation. |
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