192 Performance Analysis of Delay in Wireless Sensor Networks Jayashree C. Pasalkar Vivek S. Deshpande, Dattatary Waghole pasalkarj@yahoo.com vsd.deshpande@gmail.com dattawaghole10@gmail.com Abstract: A transport handles the congestion and reliability. In wireless sensor network (WSN), applications require a congestion control mechanism to regulate the large amount of traffic to inject within WSN to avoid packet loss and to assurance E2E reliable packet delivery. WSN researchers thus argue the presence of a transport layer for WSN similar to the Internet. Because of the resource constraint nature of sensor devices, researchers however admit that an Internet-scale transport layer will indeed be a matter of challenge. Invented story exposes detailed analysis of the requirements and constraints of a WSN transport layer. The advancements in microprocessor technology, high speed and large memories, high speed networks, Ultra Wide Band frequency spectrums, very efficient sensor network Operating Systems and miniaturization of many heterogeneous sensor devices, to name a few, have led to the development of many transport layer protocols. This seminar addresses the unique characteristics of a WSN at transport layer, classifies the attributes that characterize different functionalities offered by a transport layer. Keywords — Delay, Random access network, Optimal MAC, Wireless Sensor Network, Transport layer. I. INTRODUCTION A wireless sensor network is a group of nodes organized into an obliging network. Each node consists of processing capability (one or more microcontrollers, CPUs or DSP chips), it may contain multiple types of memory (program, data and flash memories), have a RF transceiver (usually with a single omni directional antenna), have a power source (e.g., batteries and solar cells), and accommodate various sensors and actuators. The nodes communicate wirelessly and often self- organize after being deployed in an ad hoc fashion. As shown in the in the Figure 1, users can retrieve information of interest from a WSN by inserting queries and assembling results from the base stations (or sink nodes), which behave as an boundary between users and the network. In this way, WSNs can be considered as a distributed database. It is also envisioned that the sensor networks will eventually be connected to the Internet, through which global information sharing becomes realistic Delay can take a long time for a packet to be delivered across intervening networks. In reliable protocols where a receiver acknowledges delivery of each chunk of data, it is possible to measure this as round-trip time. Due to congestion problem some time traffic will be occurs in the network. So delay will be increases and reliability of data transmission also decreases. Delay factor directly affect on network performance. AODV facilitates dynamic, multihop routing between mobile nodes desire to establish and maintain an ad hoc network. This protocol allows mobile nodes to find routes rapidly for new destination and does not require node to maintain routes to destinations that are not in active communication. AODV allows mobile nodes to respond to link breakages and changes in network topology in a timely manner. DSR is a simple and capable routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. DSDV broadcast every change in the network to every node. When two neighbours enter into communication range of each other, this result in a wide network broadcast. Local movements have global effects [1]. The modern networks are bi-directional, enabling them to control the activity of the sensors. The growth of wireless sensor networks was encouraged by military applications such as battlefield surveillance; today such networks are used in many industrial and end user applications, such as industrial process monitoring and control, machine health monitoring, and so on. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed and communications bandwidth. The topology of the WSNs can vary from a simple star network to an advanced multi-hop wireless mesh network. The transmission technique between the hops of the network can be routing or flooding. Figure 1: Accessing WSN through Internet. WSN networks have been useful in a variety of domains such as healthcare, environmental observations, military applications, and many more. Healthcare, sensors can be used in biomedical applications to improve the quality of the provided care. In this type of applications, sensors are surrounded in the human body to observe medical problems like cancer and help patients maintain their health. Trends in Innovative Computing 2012 - Intelligent Systems Design