National Conference on Emerging Technologies 2004 1 An Extended Topology for Zone-Based Location Aware Dynamic Sensor Networks Dr. S. A. Hussain, U. Farooq, K. Zia and M. Akhlaq asadhussain@pucit.edu.pk , umar@pucit.edu.pk , kashif@pucit.edu.pk and akhlaq@pucit.edu.pk Punjab University College of Information Technology, University of the Punjab, Lahore, Pakistan. Abstract: This paper presents a novel scheme for self configured dynamic sensor networks based on zones, where the sensor nodes are location aware. Location about which the sensors provide the information is always more important than identification of sensors. It is vital to deliver this information to sink involving minimum packet processing at intermediate nodes due to limited battery life and bandwidth. It is proved through simulations that this scheme ensures high success rate with minimal data flow even if sensor nodes are highly dynamic. Keywords: Sensors, Geocasting, Global Positioning System, Location Based Multicast Algorithms, Zone, Flooding 1. INTRODUCTION Sensor networks are an important ingredient of “anywhere and anytime” ubiquitous wireless next generation communication infrastructure. In this diversified yet integrated future network environments, sensor network has a role of reliable monitoring and control of variety of applications based on environmental sensing [1]. These applications range from medical and home security to machine diagnosis, chemical/biological detection and military applications. Sensor network is a combination of nodes that are used to sense data from its environment and to send the aggregated data to its control node often called sink. Figure 1 shows a typical sensor network. The sink node communicates with the task manager via core network which can be Internet or Satellite [2]. Sensors are low cost, low power, and small in size. Due to small size the transmission power of a sensor is limited. The data transmitted by a node in the field may pass through multiple hops before reaching the sink. Many route discovery protocols (mostly inherited from Ad hoc networks) [3] have been suggested for maintaining routes from field sensors to the sink(s). Due to low memory, scarcity of available bandwidth and low power of the sensors, many researchers considered these separate route discovery [3] mechanisms undesirable. Once sensors are deployed they remain unattended, hence all operations e.g. topology management, data management etc. should be automatic and should not require external assistance. In order to increase the network life time, the communication protocols need to be optimized for energy consumption. It means a node must be presented lowest possible data traffic to process. In the absence of separate (may be Proactive or Reactive [3]) route discovery protocol, the propagation of data packets towards the sink can best be controlled by equipping sensors with self awareness through GPS [4,5] coordinates. Sensors deployment is usually large in quantity and often we are interested in the location of sensors rather than the unique identification [6,7]. The scheme presented in this paper minimizes the traffic load (reducing the multihop nodes to minimum) from source sensor to the sink. The rest of the paper is described as follows. Section 2 discusses the background information for sensor networks. The motivation for the proposed scheme presented is discussed in Section 3. Section 4 discusses the proposed scheme called, ZOLA-DSN (Zone Based Location aware Dynamic Sensor Networks). Simulation results are provided in section 5. Conclusions and future work conclude the paper. 2. BACKGROUND INFORMATION Most of the networks require unique identification of nodes within a network for the transmission of information between them. Global addressing has a very lengthy format e.g. it comprises of 128 bits in IPv6. The data packet generated by sensors is generally aggregated information to the sink. So it is unwise to send an address much larger then the actual message delivered [8]. Another option can be to use local addressing but it has its own problems [9,10]. Multiple schemes to achieve better functionality with the variations / alternatives of addressing [8,9,10] have been proposed. These schemes use identifier or label for sensors identification. Identifiers are generally generated in random. [9,10] discusses address free architectures that use randomly select probabilistically unique identifiers for each new transaction rather than using static addressing. But this method may create same identifier which may interfere with the neighboring generated identifier as this model achieves both local and spatial locality [9]. Moreover, in most of sensor networks we are interested in the location about which the sensors provide information rather than the identification of sensors. Location information Figure 1: Typical Sensor Network [2]