Virtual MIMO Wireless Sensor Networks: Propagation Measurements and Fusion Performance

In this paper, we investigate the practical implications of employing virtual multiple-input-multiple output (MIMO) systems for prototyping future-generation wireless sensor networks, especially in the light of recently proposed distributed detection based decision fusion rules. In order to do that, an indoor-to-outdoor measurement campaign has been conducted recently for investigating the propagation characteristics of an 8X8 virtual multiple-input-multiple-output (MIMO) system. The campaign is conducted with transmit antennas representing the sensors deployed in different indoor environments and receive antennas mounted on an outside tower representing the decision fusion center. Channel measurements are reported when a 20 MHz wide signal is transmitted at 2.53 GHz. Measurements are collected for different spatial combinations of the transmit antennas. After analyzing the collected data, performance of different decision fusion rules are compared and tested over the measured channel. The results show that the fusion rules perform differently over different sets of measured channels. The results obtained here are important for maximizing performance and enabling air-interface design of next-generation wireless sensor networks.