Theoretical Study of the Impact of Channel Estimation Errors on the Performance of IDMA Detectors

In this paper, the performance of an Interleave-Division-Multiple-Access (IDMA) detector is considered when channel estimation errors are present. This detector can be quite effective under severe channel estimation errors when channel estimator statistics are considered. The detector is generalized for QPSK signaling. It is shown that the overall effect of the CSI mismatch can be seen as an additive noise term, without approximation. Moreover, the term is constant for all users, paths and for in-phase and quadrature components. The performances of the detector are studied by Monte-Carlo simulations. From the results, it is shown that the improvement depends on the severity of the mismatch, the number of paths and the number of users. A 10% capacity increase can be obtained with respect to the number of users.