Tradeoff between network lifetime and fair rate allocation in wireless sensor networks with multi-path routing

Abstract

The network lifetime and application performance are two fundamental but conflicting desig objectives in wireless sensor networks. Hence there is an intrinsic tradeoff between network lifetime maximization and application performance maximization. Often application performance correlates to the application data rate obtained in sensor networks. We can thus study this tradeoff by investigating the interactions between the network lifetime maximization problem and the rate allocation problem. Severe bias on the allocated rates of some sensor nodes may exist if only the total throughput of the sensor network is maximized, hence we enforce fairness on source rates of sensor nodes by invoking the network utility maximization (NUM) framework. First we consider the network lifetime as global information shared by sensor nodes. We formulate the network lifetime maximization and fair rate allocation both as constrained maximization problems. By introducing a system parameter, we combine these two objectives into a single weighted objective, and characterize the tradeoff between them. Then we give the optimality condition, and derive a partially distributed algorithm. Also, we identify the similarity between network lifetime maximization and max-min rate allocation in networks. Since the latter one can be approximated using NUM framework, we adopt the same idea for the former one, and approximate the optimal solution in the unified NUM framework. Based on this, an efficient fully distributed algorithm is derived.