Coherence bandwidth characterization in an urban microcell at 62.4 GHz

Results of experiments made at 62.4 GHz in an urban mobile radio environmen t to characterize the coherence bandwidth are presented. The correlation co efficients between signal envelopes separated in frequency are measured and expressed as functions of distance from the base station. Due to the high variation of this coefficient with distance and in order to provide accurat e estimates of the coherence bandwidth in the microcell, the correlation co efficient has to be measured over large sections. Two methods to calculate the coherence bandwidth are presented and compared. It is shown that estima ting this parameter from the frequency correlation function obtained at eac h position may yield incorrect results. The coherence bandwidths for correl ation levels of 0.5, 0.7, and 0.9 are given. A ray-tracing tool has been us ed to assist in interpreting experimental results.