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.

[1]  L. Bouchard,et al.  Fading characteristics of RF signals due to foliage in frequency bands from 2 to 60 GHz , 2002, The 5th International Symposium on Wireless Personal Multimedia Communications.

[2]  Scott Cullen,et al.  Trees and Wind: Wind Scales and Speeds , 2002, Arboriculture & Urban Forestry.

[3]  E. D. Langre.  Effects of Wind on Plants , 2008 .

[4]  H. Mayer,et al.  Wind-induced tree sways , 1987, Trees.

[5]  S. Stavrou,et al.  Measurements and modelling of wind influence on radiowave propagation through vegetation , 2006, IEEE Transactions on Wireless Communications.

[6]  Barry Gardiner,et al.  A prism-based system for monitoring the swaying of trees under wind loading , 1998 .

[7]  R. Lewenz.  Path loss variation due to vegetation movement , 1999 .

[8]  S. Vogel.  Drag and Reconfiguration of Broad Leaves in High Winds , 1989 .

[9]  S. Vogel.  Leaves in the lowest and highest winds: temperature, force and shape. , 2009, The New phytologist.

[10]  Torbjörn Ekman,et al.  Modeling the Dynamic Effects of Vegetation on Radiowave Propagation , 2008, 2008 IEEE International Conference on Communications.

[11]  Larry J. Greenstein,et al.  Ricean $K$-Factors in Narrow-Band Fixed Wireless Channels: Theory, Experiments, and Statistical Models , 2009, IEEE Transactions on Vehicular Technology.

[12]  J. Eric Salt,et al.  Effect of wind on foliage obstructed line-of-sight channel at 2.5 GHz , 2004, IEEE Transactions on Broadcasting.

[13]  David G. Michelson,et al.  Impact of wind-induced fading on the capacity of point-to-multipoint fixed wireless access systems , 2006, IWCMC '06.

[14]  N. Haritos,et al.  Mechanical stability of trees under dynamic loads. , 2006, American journal of botany.

[15]  C. Wood,et al.  Wind and Trees: Understanding wind forces on trees , 1995 .

[16]  Torbjörn Ekman,et al.  Dynamic Model of Signal Fading due to Swaying Vegetation , 2009, EURASIP J. Wirel. Commun. Netw..

[17]  D. Crosby,et al.  Time variability of the foliated fixed wireless access channel at 3.5 GHz , 2005, 2005 IEEE 61st Vehicular Technology Conference.