Channel modelling and propagation measurements for a bodyworn 5.2 GHz terminal moving in the indoor environment

Proposed applications for broadband wireless local area networks may include the use of bodyworn or handportable terminals. The proximity of the user´s body has a significant effect on the radio propagation characteristics through spatial filtering of the multipath channel. This paper compares measurements and simulations of a narrowband 5.2 GHz radio channel with a fixed transmitter and a bodyworn receiver. The modelling technique was a site-specific ray-tracing simulator incorporating a modified three-dimensional radiation pattern of the bodyworn receiver. Two indoor environments were considered, an 18 m long corridor and a 42 m² office. The results show that the received power envelope and local mean values are strongly dependent on body shadowing in relation to the direct ray. In the corridor, the predicted non-line-of sight (NLOS) mean received powers was 13.6 dB lower than for line-of-sight (LOS). In the office, the predicted NLOS received power was 5.2 dB lower than LOS. The measured body shadowing effect was lower: 5.4 dB for the corridor and 3.8 dB for the office. Further analysis of level crossing rate and average fade duration showed that the prediction tool tended to underestimate the degree of fading. This was attributed to the movement limitations of the body model used.