Research On The Lifetime And Reachability In Wireless Sensor Networks

This dissertation has contributed to the extensive researches available on the reachability and lifetime in Wireless Sensor Networks (WSNs) and motivated further the need for a better integration of the two areas in this research. Based on this motivation, several problems have been identified and addressed them comprehensively.This thesis also conducted a performance evaluation as part of this work each addressed one of two problem fields and together contributed to a complete understanding of WSNs.Firstly, the problem discussed in this research is the energy efficiency, and it discussed in details the lifetime of WSNs, the architecture of wireless sensor node, duty-cycling, energy-efficient sensor node design, and energy-efficient communication. The previous works in these areas provided a solution to the problem to proper address the lifetime of WSNs. This thesis has determined a variety of techniques to improve the energy efficiency of the system. The energy efficiency of WSN relied heavily on a number of factors, such as the lifetime, wireless sensor node architecture, duty cycling, energy-efficient sensor node design, and energy-efficient communication. Sensor nodes are responsible for transferring data from one node to another, finally sending it to the end-user or base station. The energy-efficiency of the nodes is crucial of a good performance of the system; the system is directly affected by the energy consumption of the nodes (the less energy is consumed by the nodes the longer the WNSs last). To alleviate the concern issue, techniques such as harvesting energy from sun, and LEACH architecture have been discussed in the below section. In this way, the given solution can aid in increasing lifetime of the WSN system.Secondly, this work has dealt with the problem of reachability in WSNs. More specifically, it focused on protocol design, duty-cycle adaptation, the effect of node density on duty cycle adaptation for a high reachability, the number of reached neighbors, and the effect of preamble length on duty cycle. This section specifically considered several researches on these issues and provided an agreed solution. This section concluded that the reachability of the WSN is affected by different procedures used in its design. The sensor nodes and their density are very important in the entire procedure. They affected the reachability and changed the range of the reachability in the network. Data information cannot be sent and received properly if the sensors do not reach the appropriate destination.In this work, an asynchronous sleep scheduling is proposed by an adapted duty cycle for each sensor where the duty cycle is predicated on the received power potency (RPP) predicated density estimation for each sensor node. By utilizing this proposed duty cycle the reachability is compared with that of the fixed duty cycle and the adapted duty cycle by utilizing neighborhood discovery density estimation model. The results show that the reachability of the network with an adapted duty cycle in combination with RPP predicated density estimation is two times more than that of the neighborhood density estimation in a100m x100m WSN of200sensor nodes. Further the results show the reachability is as good as in the case of the90%fixed duty cycle but is more energy efficient.