Distributed Code Assignment in Multihop Radio Networks: Object-Oriented Software Simulations

Code Assignment is one of the central problems in the management of mobile wireless networks, where a very precious resource (radio bandwidth) needs to be carefully shared among network nodes. As this problem has been shown to be NP-hard in every real world instance, no practical exact solution can be provided, and heuristic algorithms are being developed whose actual performance can hardly be calculated by theorical means; hence the development of heuristic schemes must always be accompanied by appropriate simulation software. In this paper we present a new distributed algorithm for code assignment in a multihop radio network. The algorithm is based on the Saturation-Degree coloring scheme proposed in [1], which has proved better than earlier attempts at solving the problem. A crucial parameter of the proposed algorithm is the depth of the neighborhood that must be considered when a local decision must be taken. By tuning this parameter one can obtain a tradeoff between the quality of the solution and the number of parallel passes and exchanged messages. We analyze the results of our C++ simulation programs where the proposed algorithm is compared with its sequential version and with competitive schemes proposed in the literature. Furthermore, to help analyzing the behavior of our distributed technique, we provide a graphical simulation environment written in Java.