On balancing between minimum energy and minimum delay with radio diversity for wireless sensor networks

The expected number of transmissions (ETX) metric represents the link quality in wireless sensor networks, which is highly variable for a specific radio and it can influence dramatically both of the delay and the energy. To adapt to these fluctuations, radio diversity has been recently introduced to improve the delivery rate but at the cost of increases in energy for wireless sensor networks. In this paper, we propose a scheme for radio diversity that can balance, depending on the traffic nature in the network, between minimizing the energy consumption or minimizing the end-to-end delay. The proposed scheme combines the benefit of two metrics, which aim separately to minimize the energy consumption, and to minimize delay when delivering packets to the end-user. We show by both analysis and simulation that our proposed scheme can adapt to the type of traffic that can occur in a network so that it minimizes both energy and delay for the respective traffic classes.