Combined effects of wind speed and wind direction on received signal strength in foliated broadband fixed wireless links

This paper examines the temporal variation of the received signal strength (RSS) in foliated fixed wireless links resulting from the combined effects of wind speed, changes of wind direction and movement of foliage. The results of a long-term measurement campaign at 5.8 GHz are presented. These measurements reveal some interesting and unexpected results: (a) RSS can be positively or negatively correlated with wind speed, depending on the physical foliage profile; (b) Wind direction may affect the degree of correlation between RSS and wind speed; (c) Wind direction may affect the mean level of the RSS distribution. These observations imply that the scattering effects owing to wind-induced foliage movement are not solely dependent on wind speed but also the orientation of the wind. The results presented here are useful for those deploying fixed wireless systems in foliated environments, the design of fade mitigation schemes and the determination of a more realistic wind-induced vegetation fading simulator.