Abstract
In this thesis, we proposed a new space-time encoding scheme for QPSK modulation over frequency-nonselective fading channels. This scheme alleviates the tradeoff between the diversity and the rate of space-time coding by increasing decoding complexity. We derived the space-time code design criteria over fast fading channels. This scheme consists of a systematic convolutional encoder over a ring and a spatial encoder, and in addition, an interleaver to combat with correlated fading. Simulation results have confirmed the excellent performance of our proposed scheme.