Experimental analysis of power control and element spacing for unobtrusive MIMO antenna systems

Abstract

With ever-increasing demand for wireless communications, spectral efficiency and power management are of great importance. Mobile nodes in an ad hoc network are limited by the available power, interference, and shared communication resources. Research shows that multiple-input multiple-output (MIMO) communication systems can increase capacity and mitigate interference by exploiting the multi-path nature of wireless energy. This increase in capacity is realized with an array of antennas that can transmit multiple uncorrelated streams. In order to achieve theoretical gains in capacity, several practical problems must be considered. This dissertation presents solutions to create higher quality communication systems in MIMO ad hoc networks through power management, antenna array spacing, and unobtrusive conductive polymer antennas.To show how co-channel interference can be managed in ad hoc networks, the experimental performance of several power control methods are demonstrated. These experiments were made with a multiple antenna software defined radio (SDR) testbed and verified with electro-magnetic ray tracing. In addition, the spacing between antenna array elements directly impacts the wireless channel. An analysis of the wireless channel is presented to show the impact of the antenna spacing and cochannel interference on the network capacity. A method for selecting the best antenna spacing is also described based upon the channel analysis. Finally, due to the size of mobile devices, it is difficult to incorporate MIMO systems into small form factors. A transparent, conformal antenna array was fabricated to demonstrate that antennas can be developed to fit into small form factors and perform at a high level.%%%%Ph.D., Electrical Engineering – Drexel University, 2009