The Research Of A Wireless Communication System: MIMO IDMA

Since IDMA is proposed,as a strong candidate to the multiple access technology for the 4^th mobile communication,it has been widely studied.IDMA not only inherits many advantages from CDMA,especially diversity against fading and mitigation of interference,but also has some own advantages,such as a simple Chip by Chip iterative receiver structure,high spectral efficiency,and excellent performance of multi-user access.In order to make the performance of IDMA closer to the multiple access channel(MAC) capacity limits,LDPC codes is applied,and LDPC-Coded IDMA system is presented in this paper.Computer simulation results indicate that LDPC-Coded IDMA system not only inherits many advantages from IDMA system,but also has its own predominance,such as closer to multiple access channel(MAC) capacity limits,obtains more coding gains,and supplies higher quality communication service.Furthermore,the middle rate between 0.4 and 0.5 for LDPC code is the best choice for this system.At the same time,the combination of IDMA and other key technologies in the 4^th mobile communication is indispensable.This paper introduces MIMO to LDPC-Coded IDMA,designs the system structure,and presents an iterative multi-user detection algorithm with low complexity and high performance.The simulation results show that the short or middle frame of LDPC codes entirely meet the requirements of high-speed and reliable data communications for multi-user in MIMO IDMA system.The increase of the number of users will not affect the complexity of receivers.In certain cases,the deterioration of system performance is small with the increase of user numbers.It is also well-regulated for the configuration between transmitting and receiving antenna how to affect system performance.Whether over the Rayleigh fast fading channel or quasi-static fading channel,the proposed system is of excellent performance,and is one of the best options for 4G uplink.