Radio environment simulation using RF switch matrix for MANET tests

To provide reliable communications mobile wireless networks should contain mechanisms for link quality monitoring, adaptive routing and interference avoidance. Their efficiency is one of the most critical parameters of the network, and it should be thoroughly designed and tested. To minimize time, costs and human resources, tests can be performed laboratory-based wire test-bed, using devices that emulate wireless channels and ensures results reproducibility. This article presents a concept of a laboratory test-bed, using RF switch matrix for wire-based measurements of the MANET parameters. The matrix inserts a programmable attenuation between selected RF nodes, to simulate a large-scale RF attenuation. The proposed efficient iterative method of RF switch matrix control provides values of attenuators in the network to achieve appropriate attenuations between RF nodes, maintaining predefined accuracy. Another problem is related with use of the matrix for simulation of fast and slow fading, for scenarios with mobile nodes. For these cases, attenuation is changing fast and rapidly, so the article also presents a method for reducing interference caused by switching on and off the attenuators during MANET operation.