A switch agent for wireless sensor nodes with dual interfaces: Implementation and evaluation

Data generation in wireless sensor networks could be bursty as it is dictated by the presence or absence of events of interest that generate these data. While conventional sensor nodes possessed only one radio interface, next generation sensor nodes are expected to have two (possibly more) radio interfaces, each with different range, capacity, and power consumption. Equipping sensor nodes with dual radios has its own benefits and can be quite useful in handling bursty traffic while at the same time satisfying the application´s delivery requirements. In this paper, we propose an adaptive interface switch agent that intelligently selects the interface to be used for data transmission at a sensor node based on the data burst length while taking into consideration power consumption, throughput, and endto- end delay. The proposed work generalizes earlier works in this area to enable both the source nodes and intermediate data forwarding nodes to initiate the activation of high power radios so that they can be utilized to a higher degree for convergecast communication. We have performed extensive simulations with sensor nodes containing both IEEE 802.15.4 and IEEE 802.11 compatible radios. Our simulation results indicate that: (i) the end-to-end delay and throughput achieved by the proposed interface switch agent are comparable to those achieved in a network of sensor nodes equipped only with IEEE 802.11 radios, (ii) the energy consumed in the network using our interface switch agent is a fraction of that consumed in a network of the IEEE 802.11 sensor nodes and is comparable to that of sensors using only IEEE 802.15.4 radios.