Performance evaluation of a portable radio close to the operator´s body in urban mobile environments

This paper presents computer simulation of the influence of the operator´s body on the performance of a portable radio in mobile environments. Due to the human body blocking and absorption effects, the antenna pattern is significantly changed and a strong cross-polarized field is induced. An approach called modified Doppler power spectrum (MDPS) method is proposed to study the influence by an operator´s body in mobile environments. To validate the results of the above method, we also present a second approach called direct discrete multipath (DDM) method which uses a defined a-profile distribution to relate with cross-polarization discrimination (XPD). Simulation results show that: (1) the signal envelope variations with human-body effects are also distributed according to the Rayleigh distribution, but the mean powers are decreased by a decay factor which varies according to the distance between antenna and head and (2) the closer the distance between the antenna and the head, the poorer the bit error rate (BER) performance of the radio. This means that more fading margin in the communication link budget must be counted in