Performance of IDMA system with Optimal Spreading Mechanism and Tree Based Interleaver

IDMA is being thought as a strong candidate for radio access in cellular mobile communication systems. It is attractive for wireless access because of its numerous advantages over TDMA, FDMA and CDMA. The InterleaveDivision Multiple-Access (IDMA) scheme is known for property of orthogonality amongst its user-specific interleavers. The interleavers are, therefore, referred has the heart of IDMA Transceivers. In the literature, researchers have proposed Tree Based Interleaver (TBI) which not only reduces the bandwidth requirement in comparison to that required in case of Random Interleavers (RI) but also reduces computational complexity drastically when compared with that of power interleavers. The memory requirement at receiver end and its cost problem are also solved by tree based interleaver with further reduction of the amount of information exchange between mobile stations and base stations required to specify the user-specific interleavers. Here we are using IDMA system using tree based interleaver .On comparing different spreading techniques as repition, Gold code and Walsh code spreading from simulation results, the performance is almost same for all. But from implementation point of view repition spreading requires less memory, less computational complexity, easy implementation and also defines larger number of users as compared to Gold code and Walsh code for same spreading length. During the simulation, it has been observed that IDMA system with repition spreading employing TBI outperforms its counterparts optimally. KEYWORDSModulation mechanism, Channel Model, Multiple Access Scheme, IDMA receiver,Tree Based Interleaver, random interleaver, spreading codes .