A Distributed Reconfiguration Approach for Quality-of-Service Provisioning in Dynamic Heterogeneous Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are commonly deployed in dynamic environments where events, such as moving sensor nodes and changing external interference, impact the performance, or Quality of Service (QoS), of the network. QoS is expressed by the values of multiple, possibly conflicting, network quality metrics, such as network lifetime and maximum latency of communicating a packet to the sink. Sufficient QoS should be provided by the WSN to ensure that the end-user can successfully use the WSN to perform its application. We propose a distributed reconfiguration approach that actively maintains a sufficient level of QoS at runtime for a heterogeneous WSN in a dynamic environment. Every node uses a feedback control strategy to resolve any difference between the current and required QoS of the network by adapting controllable parameters of the protocol stack. Example parameters are the transmission power and maximum number of packet retransmissions. Nodes collaborate such that, with the combined adaptations, the required network QoS is achieved. The behavior of the reconfiguration approach and the tradeoffs involved are analyzed in detail. With the use of simulations and experiments with actual deployments, we show that our approach allows a better optimization of QoS objectives while constraints are met; for example, it achieves the same packet loss with a significantly longer lifetime, compared to current (re-)configuration approaches.