Wireless Sensor Network, 2010, February, 161-167
doi:10.4236/wsn.2010.22021 Published Online February 2010 (http://www.SciRP.org/journal/wsn/).
Tree Based Energy and Congestion Aware Routing
Protocol for Wireless Sensor Networks
Amir Hossein Mohajerzadeh, Mohammad Hossien Yaghmaee
Department of Computer Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
E-mail: firstname.lastname@example.org, email@example.com
Received June 15, 2009; revised October 15, 2009; accepted November 17, 2009
Wireless Sensor Networks (WSNs) have inherent and unique characteristics rather than traditional networks.
They have many different constraints, such as computational power, storage capacity, energy supply and etc;
of course the most important issue is their energy constraint. Energy aware routing protocol is very important
in WSN, but routing protocol which only considers energy has not efficient performance. Therefore consid-
ering other parameters beside energy efficiency is crucial for protocols efficiency. Depending on sensor
network application, different parameters can be considered for its protocols. Congestion management can
affect routing protocol performance. Congestion occurrence in network nodes leads to increasing packet loss
and energy consumption. Another parameter which affects routing protocol efficiency is providing fairness
in nodes energy consumption. When fairness is not considered in routing process, network will be partitioned
very soon and then the network performance will be decreased. In this paper a Tree based Energy and Con-
gestion Aware Routing Protocol (TECARP) is proposed. The proposed protocol is an energy efficient rout-
ing protocol which tries to manage congestion and to provide fairness in network. Simulation results shown
in this paper imply that the TECARP has achieved its goals.
Keywords: Congestion Aware, Energy Efficiency, Routing Protocol, Fairness, Tree Based Routing, Wireless
1. Introduction of applications they are not rechargeable , therefore
energy consumption is the most important factor in rout-
Wireless Sensor Networks have been noticed and re- ing process for wireless sensor networks. Node’s energy
searched in recent years. These networks are composed is consumed due to using sensors, processing informa-
of hundreds or thousands of sensor nodes which have tion and communicating with other nodes. Communica-
many different types of sensors . Using their sensors, tions are the main element in energy consumption.
nodes collect information about their environment such Routing protocol directly affects communications vol-
as light, temperature, humidity, motion and etc . Sen- ume; therefore energy aware routing protocols are very
sor nodes should send their collected data to determined effective in decreasing energy consumption .
nodes called Sink. The sink processes data and performs Routing protocols which only consider energy as their
appropriate actions. Many different paths exist between parameter are not efficient. In addition to energy effi-
each node and sink. Using routing protocol, nodes de- ciency, using other parameters makes routing protocol
termine a path for sending data to sink. Similar to tradi- more efficient. For different applications, different pa-
tional networks, routing protocols in wireless sensor net- rameters should be considered. One of the most impor-
works consider different parameters in their routing tant parameter is congestion management. Congestion
process depended on their application. occurrence leads to increasing packet loss and network
WSNs have inherent and unique characteristics com- energy consumption. Congestion occurs for different
pared with traditional networks [1,2]. These networks reasons in wireless networks; first, due to limited storage
have many limitations such as computing power, storage capacity in relay nodes. When a node receives packets
space, communication range, energy supply and etc. more than its capacity, congestion will be occurred.
Nodes have limited primary energy sources and in most Second, due to inherent shared wireless link, congestion
Copyright © 2010 SciRes. WSN
162 A. H. MOHAJERZADEH ET AL.
occurred for similar reasons in wireless sensor networks. tion 4 summarizes the simulation based evaluation of the
For example, when many nodes simultaneously decide to TECARP routing protocol, and finally Section 5 con-
send packet using a shared medium, congestion will be cludes the paper.
occurred. Two main methods exist to manage congestion.
Chen et al.  divided the techniques developed to ad- 2. Related Work
dress the problem of data congestion in WSN into two
groups: congestion avoidance and congestion control. As mentioned before, energy consumption is the most
The former focuses on strategies to avoid congestion important factor for routing protocols in WSNs. Differ-
from happening and the latter works on removing con- ent energy aware routing algorithms have been designed
gestion when it has occurred. In wireless sensor networks for wireless sensor networks. In  optimal energy con-
due to limitations in resources, avoiding congestion sumption is the most important objective. Akkaya et al,
rather than controlling congestion is more reasonable