A User-Spread Interleave Division Multiple AccessSystem

Abstract: In this paper, we propose a User-Spread Interleave Division Multiple Access (US-IDMA) system that employs two way user separation using interleavers and spreading sequences to improve the performance of the system with more secure and reliable communications compared with the conventional IDMA system.These spreading sequences are not only as random as user data and independent of current symbols, but also dynamically changes from one symbol to another according to the user data.Therefore, this system offers enhanced security and privacy, due to the fact that the sequences make unwanted detection of the data by unintended receivers practically impossible.Also, simulation results show that the proposed system improves the bit error rate performance of the system in flat fading channel.

Keywords: IDMA, Interleaver, Multiple access, Spreading, User data