Space-Time Wireless Channels

Chapter 7. Second-Order Channel Statistics

Until now, we have discussed only second-order statistics such as fading rate variances and spectrum spreads. These metrics are the cornerstone of any fading analysis, but they are also somewhat nebulous. For link design, there are important statistics we would like to derive that affect performance: How often does a fading channel drop below a specific signal threshold? How long does the fading channel stay beneath this threshold? What are rigorous definitions for channel coherence?

This chapter presents statistical techniques for characterizing small-scale envelope fading of Rayleigh channels as a function of time, space, and frequency. Statistics such as level crossing rates, average fade duration, ...