ANALYSIS OF LINEAR RECEIVERS FOR MC-CDMA WITH DIGITAL PROLATE FUNCTIONS

摘要

Research presented in this contribution deals with efficiency improvement in downlink MC-CDMA system by applying slightly modified Digital Prolate Functions (DPF) as orthogonal spreading codes. Modified DPF applied as orthogonal codes in time-continues MC-CDMA result in well-concentrated users' signals in interval smaller than symbol's. The benefit of this signals' property is clear; time dispersive channels will not affect contiguous symbols seriously if no time redundancy (e.g. Cyclic Prefix) is added, that is, intersymbol interference (ISI) will be minimized. The price that is to be paid for this efficiency improvement is somewhat increased receivers' complexity. In this contribution, analysis of different receivers for downlink will be performed, applying Filter Bank (FB) as digital front-end and linear detectors: decorrelator and MMSE detector. Eventually, it turns out that the performance, using a simple decorrelator, is satisfactory enough, making this type of systems feasible to implement.