Energy Efficient Congestion Control in Wireless Sensor Networks

Introduction

Wireless interconnection of autonomous sensors over some shared medium make up wireless sensor network. This emerged network has its large number of applications including temperature, pressure, vibration, sound and etc. The collected data from the target environment is passed on to base station either directly or through multihop communication fashion. The new set of mobile WSN is the result of advancement in static WSN along with distributed robotics (Bergbreiter and Pister 2003). The network architecture of MWSN is same as is of WSN, however implicit or explicit mechanism are provided to move these sensors in space over time (Zeinalipour et al. 2008). Relative means or absolute means are used to derive the coordinates of MWSN. Localization techniques is a typical example of former while Geographical Positioning System is of later (Lingxuan and David 2004). Based on movement speed, MWSN are categorized into i) highly mobile ii) mostly static and iii) hybrid. In the first case, movement is of the speed of human, cars or airplanes. Very low velocity such as that of moving robotics comes under second given case. The thrid category is the combination of both above. Such as moving cars with sensors installed therein (Zeinalipour et al. 2008). Some exceptional challenges such as energy efficiency and congestion are posed due to the perceptibly dynamic characteristics of MWSN as well as applications of traditional wireless networks.

Since the sensor nodes are battery operated and replenishment of battery is almost impossible in some scenarios especially in the applications related to MWSN. So, energy is considered as the most vital design confront in such networks. This is also important in increasing the network lifetime and ultimately comes up with better performance with respect to latency, throughput and bandwidth parameters. This is one of the key reason that current research is mainly focused on minimizing the energy consumption ratio.

On one hand, various activities of radio such as transmission, reception, Idle listening to the channel effect much on draining the node’s energy. On the other hand, energy conservation factor is also affected by the congestion and its related effects. Congestion either arises due to fastly approaching the data at some node compared to its processing and further transmission to the ultimate destination or due to simultaneous sending of data from numerous nodes at sink nodes. This also comes with the effect of packet loss that again requires their retransmission. So, its become obvious to have its disastrous effect on node’s energy. In such scenarios, efficient and effective MAC protocol has its indispensable role in minimizing the energy consumption ratio. It allocates the medium resources in sensible way to have its contribution in achieving the target of lesser energy draining.

Based on the above detailed discussion relating to sensor node’s constraint resources, this current underlying study is on the purpose of implementing a novel mobility aware energy efficient MAC protocol for Mobile WSN. The awakening, sleeping, and listening states of nodes (scheduling algorithm) is developed for the proposed MAC has the aim to achieve relatively better performance in energy conservation. TSEEC has the assumption that Mobile Sensor Nodes have their location information through some localization technique (Zeinalipour et al. 2008). Such information is used to predict the mobility pattern via the technique presented in (Zaidi and Mark 2004)