On the diversity, bandwidth, and performance of digitaltransmission over frequency-selective slow fading channels

The issues of diversity reception, bandwidth utilization, and performance evaluation of digital transmission over slowly time-varying frequency-selective fading channels are investigated, with a transmit pulse design that is more general than previously considered. In particular, the tradeoffs among performance, bandwidth, and complexity are addressed. Three types of transmit pulses are considered and compared, including the raised cosine (RC), square-root RC (SRRC), and Gaussian pulses. Union bounds on the symbol and burst error rate are derived for maximum likelihood sequence estimation (MLSE) based on exact pairwise error probabilities for burst-mode transmission. Explicit and implicit diversity are employed to improve the system performance. The results show that the implicit diversity is flexible and easy to exploit and is a good complement to the space or other explicit diversity to further improve the system performance