衰落信道下Turbo碼性能仿真評估.pdf

1、In digital communication theory the most commonly assumed model for a transmission channel is the AWGN channel. However，for many communication systems the AWGN channel is a poor model. One fundamental type of non-Gaussia

2、n channel which often occurs in practice is the fading channel. Fading in wireless communication is the main obstruction for reliable communications. In order to alleviate the effects of channel fading，we need to use cha

3、nnel coding. Channel coding can offer enhanced error performance for digital communication systems by mapping input sequence into code sequence，which inserts redundancy to the transmission. This paper deals with a new cl

4、ass of channel codes called Turbo-codes，whose performance in terms of Bit Error Rate(BER) are close to the SHANNON limit. The main aim of this thesis is to evaluate the performance of Turbo Codes over certain fading chan

5、nels. We have used BPSK modulation scheme. We have implemented two channel models viz. Rayleigh and Rician channel models. The BER vs. SNR plots are used as performance measures through the simulations. The simulations w

6、ill be carried out in Matlab environment. In performing these intensive simulation experiments we considered various parameters such as number of decoding iterations，frame size，constraint length and so on. To validate th

7、e simulation，we compared the simulation result with theoretical result. To achieve the simulation result，coding theory related to this research will be studied in detail. From the results of the simulation，we conclude th

8、at Turbo code enable reliable communication with power efficiencies close to the theoretical limit predicted by Claude Shannon. However，its iterative decoding scheme increases receiver complexity and processing time as t