Coherence bandwidth characterisation for indoor mobile radio microcells at microwave and millimetre wave frequencies

• Main Author: Kermoal, John Phillipe
• Published: University of South Wales 1998
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.749619

This thesis reports measured and predicted results of the coherence bandwidth of indoor mobile radio microcells at 11 GHz and 62.4 GHz. Furthermore, the influence of the antennas radiation patterns and the effect of furniture on the value of the coherence bandwidth has been investigated. A two branch frequency diversity system has been developed and used to simultaneously record the amplitude variation of the sideband signals. Frequency separations in the range between 5 and 240 MHz have been used at both 11 GHz and 62.4 GHz. In order to assist in explaining experimental results, a ray-tracing algorithm based on the image method, has been developed. It considers reflections up to the third order and assumes smooth walls, all with the same dielectric parameters. The correlation coefficients between signal envelopes separated in frequency are measured and expressed as functions of distance between terminals. The level below which the correlation stays for a given percentage of time has been measured and plotted against frequency spacing to generate the frequency correlation function of the microcell. The coherence bandwidth, corresponding to correlation levels of 0.5, 0.7 and 0.9, are determined from these functions. The coherence bandwidth has also been measured at each position in the microcell and its value for a given percentage of mobile terminal locations is given. The difference between results obtained from both methods are outlined and explained. Results are presented for three corridors and a room. A comparison between experimental results obtained at 11 GHz and 62.4 GHz is also given.