Multiuser–Multipath Detection in IDMA Based HetNet: An Adaptive Cyclic Interleaving Approach

摘要

In this paper, we introduce a method of user loading for interleave division multiple access (IDMA) based two-tier Heterogeneous network (HetNet) to achieve improved performance in terms of lower bit-error rate (BER) for active micro-cell users present in the coverage area of a macro-cell base station (BS). Based on the fading scenario, the proposed method adjusts the load distribution among the macro-cell BS and the participating micro-cell BSs in the HetNet structure to guarantee relatively low BER to the mobile users. In this study, we propose a HetNet employing an adaptive cyclic interleaving technique at the IDMA transmitter and a multiuser–multipath (MUMP) detector at the receiver to support load distribution. With the aid of cyclic interleaving, MUMP detector resolves each received multipath component through multipath detection rather than conventional single path detection. Then, via theoretical study and extensive simulations, first, we demonstrate how the cyclic interleaving mechanism introduced in IDMA transmitter exploits the diversity property of the maximal-length sequence ( m -sequence). Next, the superiority of the MUMP detector over single path detectors in multipath Rayleigh fading channel is shown and also the effect of equal-gain combining?(EGC) and maximal-ratio combining?(MRC) schemes in system performance is analysed for different BS load distribution in IDMA based HetNet.