A New Path Selection Scheme for Chip-level Multiple Access Systems over Long-Spread Channels


The soft Rake in multiple access systems such as interleave division multiple access (IDMA) is the most critical part in terms of the computational complexity. In this paper, the problem of choosing effective Rake paths in such systems among multi-path components is considered. The path selection problem is formulated as a problem with a convex objective function. A decision rule for choosing the proper path number of the soft Rake based multiuser combiner is derived. The decision rule is very simple and can get quite close to the optimal scheme that cannot be implemented in practice due to its complexity. Simulation results are presented to compare the system performance with the proposed path selection scheme and that of the conventional scheme.