Study On Unequal Error Protection Based On Fountain Code

With the development of science and technology, information transmission quality and speed have drawn great attention of people. In the traditional transmission mechanism,feedback and automatic retransmission efficiency is low and increase the transmission time.Fountain code is a kind of rateless code, which doesn’t need feedback and automatic retransmission request, therefore, it saves the transfer time, avoids the problem of feedback storm.Starting from the influence factors of fountain code, the influence on fountain code encoding and decoding is made detailed study, which obtains the conclusion that robust soliton has a better distribution performance. On the basis of former study, fountain code encoding and decoding scheme is studied. Aiming at the shortcomings of the existing encoding decoding scheme, a fountain code encoding and decoding scheme based on chaotic mapping is presented, which introduces the concept of chaos and makes full use of ergodicity, uniformity and other characteristics. The simulation results show that the scheme has good stability and improves the success rate of decoding.A variety of classic fountain code unequal error protection scheme are summarized.Classic fountain codes UEP scheme includes setting weighting factor UEP scheme, unequal error protection based on Expanding Window and the replication window method to realize unequal error protection scheme. The characteristics of unequal error protection scheme is analysed after the simulation and analysis to the several schemes. Some of classic unequal error protection scheme is at the expense of decoding success rate of less important bits,and some unequal error protection feature is not obvious. On the basis of summary and analysis of simulation results, copy-extension window of fountain code unequal error protection scheme is presented. The simulation results show that the scheme can enhance the UEP features and improve the LIB error resistance performance.