(p,q) Alternate-Decimal Interleavers in IDMA system
Wu Wen · Signal Processing · 2010
Multiple access technology is a great problem in communication systems.Interleave-division multiple-access(IDMA) is a new scheme of multiple access technology.It employs a chip by chip iterative multi-user detector to separate data from different users. IDMA is attractive for the future mobile communication system for its low cost multi-user detector(MUD) and robustness to interference and noise.Since interleavers are the only means to separate data from different users,it is important to design a good set of interleavers. A set of interlevers based on reversal of(p,q) alternate-decimal indexing are designed for IDMA systems in this paper. With proper selection of p and q,orthogonal interleavers can be designed.Few registers are needed because only the values of p and q should be stored for each user.If both p and q are powers of two,the algorithm is easy to be realized in hardware.The index after interleaving can be generated by reversing the binary form block by block,and no more operations are excluded.The peak basis correlation (PBC) of the proposed interleavers and random interleavers has been analyzed in this paper.The PBC of the proposed interleavers is orthogonal, which outperform random interleavers.Bit error rate(BER) simulation results show that the IDMA system using the proposed interleavers performs better than that using random interleaves.