Relay Deployment and Power Control for Lifetime Elongation in Sensor Networks

Abstract

Abstract-In a sensor network, usually a large number of sensors transport data messages to a limited number of sinks. Due to this multipoint-to-point communications pattern in general homogeneous sensor networks, the closer a sensor to the sink, the quicker it will deplete its battery. This unbalanced energy depletion phenomenon has become the bottleneck problem to elongate the lifetime of sensor networks. In this paper, we consider the effects of joint relay node deployment and transmission power control on network lifetime. Contrary to the intuition the relay nodes considered are even simpler devices than the sensor nodes with limited capabilities. We show that the network lifetime can be extended significantly with the addition of relay nodes to the network. In addition, for the same expected network lifetime goal, the number of relay nodes required can be reduced by employing efficient transmission power control while leaving the network connectivity level unchanged. The solution suggests that it is sufficient to deploy relay nodes only with a specific probabilistic distribution rather than the specifying the exact places. Furthermore, the solution does not require any change on the protocols (such as routing) used in the network.

Connectivity-aware network maintenance and repair via relays deployment

“…Recently, there have been numerous network maintenance algorithms [2], [6]- [8]. In [2], the problem of provisioning additional energy on the existing sensors along with deploying additional relays in two-tier wireless sensor networks was considered.…”

“…A relay deployment algorithm that maximizes the minimum sensor lifetime by exploiting the cooperative diversity was proposed in [6]. In [8], a joint design of relay deployment and transmission power control was considered to maximize the network lifetime. In that work, there is no solution to deploy the relays in particular locations, instead the probability distribution of the relays' location is quantified.…”

“…The weight of a constructed edge equals the summation of the weights of the edges connecting the relay with the two sensors. Finally, the constraint 1 T x = K in (8) indicates that the number of chosen relays is K.…”

“…Therefore, we need an efficient and quick way to solve (8). The optimization problem (8) can be thought of as a general version of the one considered in [20].…”

“…We note that the optimal value of the relaxed problem in (10) is an upper bound for the optimal value of the original problem (8), as it has a larger feasible set. Similar to (6), the Fiedler value of L(x) can be expressed as…”