An integrated energy aware wireless transmission system for QoS provisioning in wireless sensor network

A significant amount of research efforts have been done to improve the energy efficiency of wireless sensor network (WSN). However, not much has been done to optimize the Quality of Services (QoS) of WSN. Actually, energy efficiency should be jointly optimized with QoS to make WSN useful. In this paper, we develop an integrated adaptive wireless transmission system for WSN to meet the QoS requirements in an energy-aware fashion. The QoS requirements in the application layer, the modulation and transmission schemes in the data link layer and physical layer are jointly analyzed and integrated into a single framework. In this framework, the cluster-based protocol is used, where the cluster heads form a multi-hop backbone. The intra-cluster QoS performance and inter-cluster QoS performance are both analyzed. Based on the results, the overall energy consumption and QoS in terms of BER performance, end-to-end transmission latency and packet loss ratio are modelled by the communication parameters of the cluster heads including the modulation level (bits per symbol) and transmit power. According to the model, a centralized off-line protocol is designed in the integrated framework to adjust the communication parameters of the cluster heads for fixed QoS provisioning. And a distributed online protocol is also designed for dynamic QoS provisioning. Extensive simulation results under various experimental settings demonstrate the energy-saving performance of the proposed integrated system. The ability to adapt to time-varying delivery quality requirements is also tested.