Space-Time Coding-Assisted Double-Spread Rake Receiver-Based CDMA for Dispersive Rayleigh Fading Environments

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Description/Abstract

In this contribution we propose a novel Space-Time Coding-Assisted Double-Spread Rake Receiver (STC-DS-RR) based CDMA scheme for downlink (base to mobile transmissions over dispersive Rayleigh fading channels. The STC-DS-RR scheme invokes Turbo Convolutional (TC) channel coding and Space-Time Block Coding (STBC) fro achieving both time and space diversity gains in addition to the path diversity gain provided by the dispersive Rayleigh fading environments. The double-spreading mechanism of the STC-DS-RR scheme is capable of detecting the wanted user’s channel-impaired wideband signals with the aid of a low-complexity Rake receiver, without resorting to complex multi-user detection. The performance of the proposed scheme was investigated using Quadrature-Phase-Shift-Keying (QPSK), when communicating over dispersive channels. It was shown that the wideband scheme is capable of achieving $Eb/N0$ gains up to 35 dBs in comparison to an uncoded narrowband sing-transmitter scheme.