Research On Superposition Coded Modulation For Interference Channels

With the development of wireless communication technology,the use of multi-antenna and advanced coding technology has greatly improved the spectral efficiency and reliability of the system.However,the increasing number of users will bring more serious interference between users.How to effectively reduce the interference between users is a difficult problem to be solved in the field of wireless communication.In this thesis,the layered superposition coding modulation technology is deeply studied for the multi-user Gaussian interference channel.A layered superposition coded modulation system based on BICM-ID is proposed and combined with high-order modulation technology to improve the spectral efficiency of the system.First,the achievable rate region of interference channel is studied in this paper.The HK strategy is also introduced for the capacity region of Gaussian weak interference channel.Then,the Han-Kobayashi achievable rate region is given.Then,the capacity regions of two strong and weak interference channels under BPSK input are calculated and simulated.And the performance of the adaptive splitting scheme,the symmetric splitting scheme,the orthogonal transmission scheme are simulated by using the reachable rate as the reference standard,combined with the two-user symmetric cyclic interference channel.The performance of four different power allocation schemes under different signal-to-noise ratio(SNR)is compared.Then,the thesis introduces the multilevel coded modulation system.Based on the multilevel coded modulation,a superposition coded modulation system for point-to-point channel is proposed.Finally,the performance of serial iterative decoding scheme and parallel iterative decoding scheme for multilevel coded modulation system are simulated and compared.At the same time,the multi-layer coded modulation system is simulated by serial multi-stage iterative decoding and layered superposition coded modulation system is simulated by parallel and serial multi-stage iterative decoding.The simulation results show that the layered superposition coded modulation system has better performance.Furthermore,based on the two-user standard Gaussian interference channel as the basic channel model,the BICM-ID technology is introduced and a strong or weak Gaussian interference channel BICM-ID transmission scheme is achieved.Under the given simulation conditions,the achievable rate pairs of this scheme are compared with the theoretical achievable rate regions under different inputs.Then,based on the strong and weak interference channels BICM-ID transmission scheme is proposed.Combined with the multilevel superposition coded modulation technology,the interference channel multilevel superposition coding modulation system based on BICM-ID is realized.The simulation results show that the BER performance has been improved.And then the improved decoding algorithm for the component codes of the interference channel multilevel superposition coded modulation system based on BICM-ID improves the decoding performance.Finally,the high-order modulation technology is introduced to realize the high-order multilevel superposition coding modulation system,which improves the spectral efficiency.