The Beauty of the Commons: Optimal Load Sharing by Base Station Hopping in Wireless Sensor Networks

Abstract

In wireless sensor networks (WSNs), the base station (BS) is a critical sensor node whose failure causes severe data losses. Deploying multiple fixed BSs improves the robustness, yet requires all BSs to be installed with large batteries and large energy-harvesting devices due to the high energy consumption of BSs. In this paper, we propose a scheme to coordinate the multiple deployed BSs such that the energy supplies required by individual BSs can be substantially reduced. In this scheme, only one BS is selected to be active at a time and the other BSs act as regular sensor nodes. We first present the basic architecture of our system, including how we keep the network running with only one active BS and how we manage the handover of the role of the active BS. Then, we propose an algorithm for adaptively selecting the active BS under the spatial and temporal variations of energy resources. This algorithm is simple to implement but is also asymptotically optimal under mild conditions. Finally, by running simulations and real experiments on an outdoor testbed, we verify that the proposed scheme is energy-efficient, has low communication overhead and reacts rapidly to network changes.

Virtually Moving Base Stations for Energy Efficiency in Wireless Sensor Networks

“…When the initially availaible energy of BSs is small, OneMove is very close to the optimum achieved by MultiMove and MultiMove-A. Therefore, in this scenario, virtually moving multiple BSs degrades into the scheme of virtually moving one BS as in [19]. When the initially availaible energy of BSs increases, the increase of lifetime of OneMove diminishes and Multi-Fixed outperforms OneMove, because the bottleneck of the network lifetime is shifted from BSs to sensor nodes.…”

“…Then, we will formally formulate the scheduling problem, namely, the virtuallymoving BSs problem. At the end of this section, we will show why our proposed scheme is more energy efficient than the previously proposed schemes [5,11,17,2,19].…”

“…It offers two additional differences with physical motion of the BSs (e.g., [2,14]): (i) In the virtual-movement scheme, the number of active BSs selected at different times can be changed, contrary to the physical-movement scheme, and (ii) in the virtual-movement scheme, BSs are considered to have a finite energy supply like sensor nodes because BSs are also installed in the sensing field; whereas in the physicalmovement scheme, BSs are, to the best of our knowledge, always assumed to have an infinite energy supply. In our recent work [19], we discussed virtually moving one active BS and implemented this scheme in a real WSN. In this paper, we consider the more general scheme where multiple BSs are virtually moving.…”

“…OneMove [2,19]: In this scheme, we schedule the virtual movement of one BS on a finite set of candidate locations for maximizing lifetime. This is equivalent to selecting at most…”

“…Let the constants of energy consumption rates be csc = 1, cst = 1, csr = 1, c lc = 10 and c lt = 1 (We select these parameters to reflect the real energy consumptions of BSs and sensor nodes. More details can be found in our recent paper [19]). Let the initially availaible energy of all BSs be ei = 5000, ∀i ∈ V b and let that of all sensor nodes be ei = 3000, ∀i ∈ Vr.…”