The Design Of Interleavers And The Research Of System Performance In IDMA

In recent years, with the vigorous development of wireless communication industry, there are greater demands for the service of wireless communication which lead to be the concerned focus on the"Beyond Third Generation wireless communication (B3G). One of the critical techniques in wireless communication is multiple access which makes a method to distribute different channels to different users and permits any subscriber to use any circuit in the system without interference. Among all kinds of MA technique, interleave-division multiple-access (IDMA) was studied and popularized by the team of Prof. Ping Li, City University of Hong Kong for the past few years. IDMA uses chip by chip interleaver to separate users in the basis of CDMA. IDMA has the characteristics of low complexity and high precision. However, it still contains some problems such as the practice of interleaver. Interleavers which are unique to each subscriber with required length are important equipments in IDMA system. Hence, the way to practice the distribution from base station to mobile station through air interference is a direction of research. Generally speaking, people use traditional random interleaver which costs a lot of bandwidth to transmit the whole interleaver matrix of each user.Our research in this paper focuses on the interleavers and some important parameters in IDMA system. The objectives are as follows, first, we need to design proper interleavers which would not reduce the BER but effectively save the bandwidth in transition. Second, we need to control the parameters effectively to optimize the system. In this paper we first introduce the basic theory of interleaver and the research situation at home and abroad. Then we briefly introduce all kinds of MA techniques and give the basic system model, theory, and key technique of IDMA. Later, through the research of interleaver we realize the simulation of the nested interleavers based on pseudo-random noise sequence. In the base of it, we design the nested interleavers based on 3GPP and the random cyclically shifted interleavers based on pseudo-random noise sequence. The BER of three interleavers is almost the same as traditional interleaver. But it can save the bandwidth of transmitting interleavers. Finally, we will analyze and compare the arguments of interleave to help us practice the system. In the last part, we give some conclusion and future development.