A Comprehensive Survey of Congestion Control Protocols in Wireless Sensor Networks

Congestion control and reliable data delivery are two primary functions of the transport layer in wired and wireless networks. Wireless sensor networks (WSNs) are a special category of wireless ad hoc networks with unique characteristics and important limitations. Limitations concern their resources, such as energy, memory, and computational power, as well as their applications. Due to these limitations and characteristics, the Transmission Control Protocol (TCP), the legacy protocol that implements congestion control and reliable transmission in the Internet, cannot apply to WSNs in its traditional form. To deal with this unavailability of a standard solution, many efforts are taking place in this area. In this paper, we review, classify, and compare algorithms, protocols, and mechanisms that deal directly with congestion control and avoidance in WSNs.

I. Introduction

WIRELESS SENSOR NETWORKs (WSNs) are wireless networks consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion, and pollutants, among others, at different locations [1], [2]. Applications using sensors are being increased. A wide range of them is now deployed in civilian areas like habitat observation [3], [4], health monitoring [5], object tracking [6], [7] etc. Intense study has been carried out concerning many aspects of WSNs especially in the physical layer [8], [9], MAC layer [10]– [12], and network layer [13]– [16]. Lately, the problem of congestion control and avoidance has also attracted a lot of attention. Many research efforts exist in literature that justify the need of congestion control in WSNs. Papers like [17] argue on this issue and provide numerical results, while a number of other documents like [18] and [19] analyze and provide specific solutions on this problem.