World Applied Sciences Journal 19 (1): 38-46, 2012 ISSN 1818-4952; © IDOSI Publications, 2012 DOI: 10.5829/idosi.wasj.2012.19.01.1514 Corresponding Author: Zeynab Mottaginia, Department of computer engineering, Tabriz branch, Islamic Azad University, Tabriz, Iran. 38 Distance and Energy Aware Routing Protocol for Delay Tolerant Mobile Sensor Networks Zeynab Mottaginia, Somaiyeh Dabaghipoor and Ali Ghaffari Department of Computer Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran Abstract: Delay Tolerant Mobile Sensor Networks (DTMSNs) are a category of emerging networks that experience frequent and long-duration partitions. Compared with the conventional networks, the distinct characteristic is that there is no end-to-end connectivity between source and destination. The network topology may change dynamically and randomly. This characteristic and non-existence of an end-to-end path poses a number of challenges in routing in DTMSNs. So, Utilizing multi-replica schemes to improve the routing performance is reasonable. Most of the presented multi-replica approaches distribute many copies of the messages into the network for increasing the packet delivery rate. This operation consumes a large amount of constrained resource of DTMSNs. To solve this problem we propose a Distance and Energy-Aware Routing protocol (DER), which cut down the replicas based on the distance between the sensor nodes and sink node and the residual energy of the sensor node. The packet delivery probability is based on sink meeting frequency and nodes movement direction. Then we improve our protocol by using multiple sink called Multi-Sink Distance and Energy Aware Routing protocol (MSDER). Simulation results indicate that our proposed protocol achieves higher message delivery ratios with lower transmission overhead and data delivery delay than existing DTMSNs routing protocols. Key words: Delay tolerant mobile sensor networks Routing protocols Multi-sink INTRODUCTION as node mobility, frequent and prolonged communication In recent years, many routing protocols have resources limitations. A DTMSN under our consideration proposed for wireless sensor networks (WSNs). consists of two types of nodes, the wearable sensor Traditional methods of routing are suitable for many nodes and sink nodes. The former are attached to people sensor applications, but they cannot be applied to (or other mobile objects), collecting information and the scenarios with intermittent and low forming a loosely connected mobile sensor network for connections because of sparse network density, sensor information delivery. A number of high-end nodes nodes mobility and energy limitation. Two practical (e.g. mobile phones or personal digital assistants with examples of this scenario are pervasive air quality sensor interfaces) which serving as the sinks to receive monitoring and flu virus tracking. In these examples for data from wearable sensors, are deployed at strategic the most accurate and efficient measurement, wearable locations with high visiting probability or carried by a sensors that adapt to human activities has been bound. subset of people. AS a result, the connection between the mobile sensors One of the methods of data gathering in DTMSNs, is poor and thus forming a well connected mesh network are multi-replica schemes that generate multiple replicas to transfer data through end-to-end connections between for each message. Distributing a message to a large sensor nodes and sinks is difficult. number of nodes will increase the probability of packet In order to deal with this problem, Delay Tolerant delivery rate. For a DTMSN that has limited resources, Mobile Sensor Networks (DTMSNs) [1-5] has been duplicate messages will increase traffic overhead, introduced. DTMSNs are the subset of the Delay Tolerant collision, delay and energy consumption of mobile Networks (DTNs) [6-12] which have many features such nodes. interruption between nodes, delay tolerance and