Computer-Aided Modeling of Spread Spectrum Packet Radio Networks

Closed-form expressions for the performance of radio networks are generally not available. For spread spectrum networks, it is not even clear how to represent the underlying network, since the existence of links is heavily dependent on activity in other parts of the network. We have developed a set of computer-based modeling tools to help understand the performance and behavior of these networks. These tools allow for numerical evaluation of important network performance measures and experimentation with network parameters. A connectivity model for a direct sequence spread spectrum packet radio network has been developed. This model allows the computation of network throughput and can be used to study routing techniques. Our current model places direct sequence spread spectrum networks on an equal footing with narrowband networks which have been modeled using the collision channel and transmission range concepts. We describe the mathematical models and algorithms used to evaluate network performance and present several examples to demonstrate the impact of various parameters.