Low-Antenna Ultra Wideband Spatial Correlation Analysis in a Forest Environment

Impulse ultra wideband (UWB) communications promises a number of potential benefits for use in wireless sensor networks-particularly in forest environments where it can provide robust operation along with the ability to combine communications with precision position location. Additionally, MIMO communications for UWB provides the ability to take advantage of the rich multipath diversity inherent to UWB communications in order to provide enhanced robustness to fading as well as improved coverage in non line-of-sight scenarios. In this paper, we present a detailed analysis of the spatial correlation of UWB signals in a forest environment. Propagation measurements were performed using a 620 picosecond duration UWB pulse in four different forest environments: light brush, light, medium, and dense forest at distances of up to 50 meters. The mean spatial correlation was observed to vary based on forest environment, antenna type, antenna array orientation, and transmitter-receiver separation distance. These measurement results should aid in the development of MIMO algorithms for UWB outdoor communications.