Problem
A. It is known that outdoor wireless communications (say an urban cell with 300 meters radius) suffer serious degradation when we transmit symbols in series at high rate. Explain why? Briefly describes what kind of measurements you need to do to estimate the maximum acceptable symbol rate.
B. Efficient communications under multipath and mobility conditions require knowledge of the channel. How often should we measure he channel conditions? Relate your answer to the concept of "coherence time"