Spatial and Polarization Characterization of MIMO Channels in Rural Environment

To demonstrate a real-time, mobile, networked MIMO system in a realistic tactical environment, the Defense Advanced Research Projects Agency (DARPA) has instituted a program called Mobile Network MIMO (MNM) [1]. The first stage of this program is to demonstrate such a system in a rural foliated environment using 20 MIMO equipped nodes using an ad hoc network in bandwidths of 1 MHz, 10 MHz, and 25 MHz, reaching a total network throughput of up to 1 Gbps. Each node is an SUV with 8 transmit and 10 receive antennas. For any particular link both nodes are naturally at ground level. Such node placement necessitates a channel measurement and modeling effort to determine quantities such as spatial correlations, delay spread as well as propagation loss. Some of the key propagation questions are whether the channels offer enough scattering richness to benefit from MIMO systems. Also of importance is determining the delay spreads experienced in rural environments ranging from densely wooded to open field with large but sparse clutter within Line of Sight. Results of channel characterization measurements are reported. A wideband MIMO model is presented based on the measurements.