Channel modeling and performance of Zigbee radios in an industrial environment

In this paper we describe measurements of wireless propagation characteristics to develop path loss models in industrial environments. The models for path loss we develop are two-slope models in which the path loss is a piecewise linear relation with the log distance. That is, the path loss is a inverse power law with two regions, two exponents and a break point, that are optimized to find the best fit to the measured data. Second, the multipath power delay profile is determined. We use a reference measurement and the CLEAN algorithm for processing the measurements in order to determine an estimate for the impulse response of the channel. From this the delay spread of the channel can be determined. Finally we discuss the performance of Zigbee receivers. We compare the performance of different receiver structures for the O-QPSK type of modulation used as one Zigbee physical layer.