Hierarchical Routing Protocols in Wireless Sensor Networks: A Survey and its Comparison

In Wireless Sensor Networks (WSN), profound research articles are presented to address the hierarchical routing protocols which reduce the energy consumption of sensor nodes and also prolong the life of the network. The state of art of this research article focus on the survey of different hierarchical routing protocols which is utilized to efficiently deliver the sensed data from source to sink node. This article presents a detailed survey on major clustering techniques LEACH, SEP, PEGASIS, and TEEN. Also, this article strongly examines about the advantages and limitations of each hierarchical routing protocol with its recent research issues. Finally, the paper concludes with some of the research issues in hierarchical routing protocols of wireless sensor networks

Design and Comparison of LEACH and Improved Centralized LEACH in Wireless Sensor Network

A WSN consists of a setup of sensor nodes/motes which perceives the environment under monitoring, and transfer this information through wireless links to the Base Station (BS) or sink. The sensor nodes can be heterogeneous or homogeneous and can be mobile or stationary. The data gathered is forwarded through single/multiple hops to the BS/sink. In this paper, propose improvements to LEACH routing protocol to reduce energy consumption and extend network life. LEACH Distance Energy (LEACH-DE) not only selects the cluster head node by considering that the remaining energy of the node is greater than the average remaining energy level of the nodes in the network, but also selects the cluster head node parameters based on the geometric distance between the candidate node and the BS. The simulation results show that the algorithm proposed in this work is superior to LEACH and LEACH-C (Centralized) in terms of energy saving and extending the lifetime of wireless sensor networks

QoS-Based and Secure Multipath Routing in Wireless Sensor Networks

With the growing demand for quality of service (QoS) aware routing protocols in wireless networks, QoS-based routing has emerged as an interesting research topic. A QoS guarantee in wireless sensor networks (WSNs) is difficult and more challenging due to the fact that the available resources of sensors and the various applications running over these networks have different constraints in their nature and requirements. Furthermore, due to the increased use of sensor nodes in a variety of application fields, WSNs need to handle heterogeneous traffic with diverse priorities to achieve the required QoS. In this thesis, we investigate the problem of providing multi-QoS in routing protocols for WSNs. In particular, we investigate several aspects related to the application requirements and the network states and resources. We present multi-objective QoS aware routing protocol for WSNs that uses the geographic routing mechanism combined with the QoS requirements to meet diverse application requirements by considering the changing conditions of the network. The protocol formulates the application requirements with the links available resources and conditions to design heuristic neighbor discovery algorithms. Also, with the unlimited resource at the sink node, the process of selecting the routing path/paths is assigned to the sink. Paths selection algorithms are designed with various goals in order to extend network lifetime, enhance the reliability of data transmission, decrease end-to-end delay, achieve load balancing and provide fault tolerance. We also develop a cross-layer routing protocol that combines routing at network layer and the time scheduling at the MAC layer with respect to delay and reliability in an energy efficient way. A node-disjoint multipath routing is used and a QoS-aware priority scheduling considering MAC layer is proposed to ensure that real time and non-real time traffic achieve their desired QoS while alleviating congestion in the network. Additionally, we propose new mechanism for secure and reliable data transmission in multipath routing for WSNs. Different levels of security requirements are defined and depending on these requirements, a selective encryption scheme is introduced to encrypt selected number of coded fragments in order to enhance security and thereby reduce the time required for encryption. Node-disjoint multipath routing combined with source coding is used in order to enhance both security and reliability of data transmission. Also, we develop an allocation strategy that allocates fragments on paths to enhance both the security and probability of successful data delivery. Analysis and extensive simulation are conducted to study the performance of all the above proposed protocols