Research On Optimization Technologies Of Fountain Coded Coordination Transmission In Multiple Relay Systems

At present,the communication traffic in the fields of mobile Internet and the Internet of Things has increased dramatically,which has brought massive data transmission.Breakthroughs in the field of wireless communication are urgently needed to achieve efficient and reliable data transmission at high rates.Thus,this paper focuses on the optimization of fountain codes and relay cooperative coding techniques.Firstly,the development history and prospects of wireless cooperative communication are briefly described,and the current status and significance of the research on coding technology are emphasized.Then,the principle,coding and decoding of fountain code are summarized and the difference between decoding algorithms are compared and analyzed.So,the improved fountain code algorithm such as optimization degree and coding scheme proposed.Finally,a new relay selection scheme based on feedback information is proposed at the relay cooperative transmission model and the fountain code is optimized.The main contents of the full text are as follows:1.In view of the current channel coding rate fixed and wasteful power consumption,the fountain code encoding and decoding algorithms are introduced.First,the principle of fountain code and common coding and decoding algorithms are introduced.Then,for the compilation issues of traditional long fountain code,a consolidation degree optimization scheme is proposed.Based on the simplest anti-jamming model,it derives a further optimized instant merge scheme under the model with high probability of interruption.Finally,under the channel propagation model,the increasing degree of feedback channel introduction is used to improve the corresponding coding scheme.The simulation results show that the combination degree optimization and sub-merging optimization schemes reduce the bit error rate of the anti-interference network under high transmission rate and high interruption probability respectively,and the progressive coding scheme reduces the compilation code complexity under the condition of ensuring the source coverage.2.For the problems of excessive power consumption and complex implementation of multi-relay cooperative network,the optimal relay selection algorithm is proposed.Based on the multi-relay network model,a threshold-based relay selection scheme is introduced to save system resources.Then,to optimize the relay selection scheme,a secondary relay selection scheme is proposed.and it only needs to occupy a small amount of spectrum resources,and performs channel estimation and decoding information to optimize relay nodes with high channel quality and large diversity gain.Compared with the traditional threshold selection scheme,the relay computing capability is reduced and a larger diversity gain is obtained.The simulation results show thatcompared with the traditional decoding and forwarding(DF)scheme,the proposed scheme has less interruption probability,lower error rate and better overall performance.3.For the problem of the low spectrum utilization of the existing relay network with ARQ mechanism,a relay cooperation scheme using fountain code is introduced.According to the feedback channel of original system model,a fountain code improvement scheme based on feedback information is proposed.The scheme estimates the channel quality by establishing the information symbol state matrix.On this basis,the selection weight vector of information symbols is calculated according to the proposed algorithm,which improves the coverage of effective symbols and reduces the redundant information.The simulation shows that the fountain code with feedback has a better improvement on the system error rate.When the bit error rate is 10-2,the scheme has gains of 0.5 d B,1.2 d B,and 1.5 d B in the cooperative transfer(DF),selective forwarding(SD),and amplified forward(AF)cooperative transmission,respectively.This dissertation mainly studies the optimization scheme of fountain code and relay cooperation model,and combines the two modes of operation.Research shows that the performance of collaborative systems based on the two has improved significantly.Moreover,the proposed improvement scheme has high spectral efficiency and low coding and decoding complexity,which is convenient for the development of mobile communication services in the future.