| Interleave-Division Multiple Access (IDMA) is a novel communication model. It was proposed by Prof. Li Ping coming from City University of Hong Kong. Comparing with the traditional DS-CDMA, IDMA systems adopt different interleavers to separate users, rather than the spread spectrum process. The user end detects information through iteration decoding. Besides, under the process of interleaving and de-interleaving, the user end deals the Multiple-Access -Interference (MAI) as white noise. So the interleavers' designs are very important to IDMA systems. The interleavers can be generated randomly and independently. But, this kind of interleavers needs a lot of memory and bandwidth resources, which is not suitable for hardware implement. So we hope to find some way to implement the interleaver through a simple algorithm. Due to the fact of exiting a lot of documents about the Turbo interleavers, so if we could find some link between Turbo interleavers and IDMA interleavers, it can reduce our work greatly.According to the problems above, we analyze and implement interleavers for IDMA systems. The main task includes:1) On the basis of matrix model of interleavers, we analyze the characteristic of interleavers, and the relationship between interleavers and de-interleavers。2) Analyze the pattern of Turbo code and introduce several typical interleavers for Turbo code. Analyze the framework of IDMA, and introduce several typical interleavers for IDMA systems.3) On the basis of simplified model of IDMA, we perfect the rule for IDMA interleaver design, and design two interleavers: shifting interleavers and 2-Dimension interleavers.4) Finally, we implement the IDMA source based on FPGA. |
