Root Cause Analysis of Congestion in Wireless Sensor Network

Abstract

ABSTRACT In wireless sensor networks data, which get generated, is not always same; some data may be more important than others and having different priorities. As deployment sizes and data rates grow, congestion becomes a major problem in these networks. The congestion results in arbitrary dropping of data packets that reduce the overall network throughput. In this paper, we discuss the various parameters (root causes of congestion), which help us to avoid and control the congestion in the wireless sensor network. The parameters consider in this paper are input/output flow rate, node density, non-linear or unbalanced distribution of load, processing / service time of node and reliability of network. Categories and Subject Descriptors Wireless Communication General Terms Algorithms, Reliability Keywords Wireless Sensor Network, Congestion control and avoidances. 1. INTRODUCTION Wireless sensor Network consist of small microcontroller fitted with sensors and some means of communication radios. They are distributed over wide area and transmit gathered data to one or many central nodes called as Sink or also know as base station. Wireless sensor network (WSN) is one of the emerging research areas that provide designated services such as disaster prevention, environment monitoring, medical monitoring, habitat monitoring, military surveillance, inventory tracking, intelligent logistics, and health monitoring. These networks deliver numerous types of traffic, from simple periodic reports to unpredictable bursts of messages due to this congestion control in wireless sensor network is very rare event. Congestion occurs in WSN due to i) Radio channel interference, ii) Addition and removal of sensor nodes, iii) Lastly sensed event cause bursts of messages. WSNs have some problems to be overcome, for example energy-conservation congestion control, reliability data dissemination, and security. These problems often involve in one or several layers top-down from application layer to physical layer, and can be studies separately in each corresponding layer, or collaboratively cross each layer. One of the important problem, congestion control may involve in only transport layer, but energy-conservation may be related to physical layer, data link layer, network layer, and high layers. Many researchers recently turn their attentions to transport layer protocols, which are important for reliable data dissemination and energy-conservation for WSNs. Congestion causes many problems when sensors receives more packets than that its buffer space, the excess packets has to be dropped energy consumed by sensor nodes on the packet is wasted. And if further packet has traveled, the more waste is, which in turn diminish the network throughput and reliable data transmissions. Congestion control studies how to recover from congestion. Congestion avoidance studies how to prevent congestion from happening for this we have to monitor the parameters which can helps us to avoid congestion in WSN which is the subject of this paper.The remainder of the paper is organized as follows. Section 2 lists existing congestion control protocol. Section 3 present parameters, which help to avoid congestion. And lastly Section 4 concludes the whole paper on the note of future work.