This problem is referred to as the reachback problem. In this work we focus on a more fundamental implication of reachback on operational network lifetime of 802.15.4-based wireless sensor networks. This paper proposes the joint minimization of two network lifetime metrics, previously proposed for independent use, to more accurately characterize the degree of longevity of wireless sensor networks. The method uses the k-shortest simple path algorithm and a dynamic programming method rooted in operational rate-distortion (RD) theory to increase the operational lifetime of wireless sensor networks. Wireless Sensor Networks (WSN) consists of a large number of inexpensive, spatially distributed devices that collect sensor readings of their environment ([6], [7] ). It is well known that WSNs are constrained by limited battery life and once deployed battery power cannot be replenished. In general, communication between sensor nodes and a base station can take place directly in a single hop or over multiple hops. In the multi-hop communication model sensor nodes report data to a base station and cooperate to forward data packets from other sensor nodes positioned farther away from the base station. Such a many-to-one communication model gives rise to what is described as the reachback problem in networks in general and WSNs in particular (Servetto [2] defines the reachback channel for multi-hop WSNs with a mobile base station. Nevertheless, we refer to the multi-hop channels with both mobile and stationary base stations as reachback channels). The generalized reachback problem applies to any network obeying a many-to-one communication model. Some sensors will be situated farther away from the base station than others. Such sensors cannot communicate directly with the base stations and employ multi-hop communication to send data to the base station using the intermediary sensors. Traffic flows from the edges of the sensor network towards the base stations. Thus, the volume of traffic relayed by nodes closer to the base station is significantly higher than that of nodes farther away. Therefore, nodes located closer to the base station are consuming power at higher rates. Eventually these nodes will run out of battery power sooner than more distant nodes and die. Once all nodes within direct communication range of the base station stop functioning, the network will experience a partition ([26]) with the base station completely cut off from the rest of the WSN. Although the occurrence of the network partition is inevitable, our work attempts to delay it by selecting a set of routes that produces more uniform, spread-out energy consumption. This is achieved by selecting suboptimal paths that reduce the traffic load on some sensors. In the context of WSNs, the capacity, congestion and compression aspects of the reachback channel have been previously In this paper, we address the adverse effect of the reachback problem on the lifetime of IEEE 802.15.4 WSNs by pursuing an optimization framework rooted in more fundamental disciplines such as information theory [20] . In particular, we aim at identifying the optimum WSN routing for all nodes within a given sensor network by following a jointoptimization approach that is inspired by an operational RateDistortion (RD) theoretical sense [22]- [25] . Under operational RD theory, an encoder effectively minimizes both the rate R and level of distortion D resulting from the representation of a random source by a distorted (quantized) version of that source. In the case of WSN routing under the reachback problem, we propose to simultaneously optimize two energy-related parameters (or network lifetime measure), which are analogous (although not identical) to the rate R and the distortion D in operational RD theory, in order to maximize the lifetime of any given sensor network. In addition to improving the lifetime of WSN networks significantly, our approach leads to important insight into optimum routing within these networks. Furthermore, one key issue that must be addressed under the proposed RD-like framework is the complexity of the overall scheme that identifies the optimum routing of every node in a WSN. For any practical WSN with a reasonable number of nodes, the complexity of finding the optimum route for every node becomes prohibitively expensive. Hence, we develop a novel dynamic programming algorithm that attempts to identify the optimum overall routing solution of a given IEEE 802.15.4 WSN that maximizes its lifetime. In particular, the proposed approach identifies a set of routes that perform close to the optimum routing while maintaining very low-complexity. This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the IEEE ICC 2006 proceedings.
In REF , a method is introduced using the k-shortest simple path algorithm and a dynamic programmming method rooted in operational rate-distortion (RD) theory to increase the operational lifetime of a multi-hop 802.15.4 wireless sensor networks.
Increasing Network Lifetime Of An IEEE 802.15.4 Wireless Sensor Network By Energy Efficient Routing
2006 IEEE International Conference on Communications
2006 IEEE International Conference on Communications
Computer Science