Research On Key Technologies Of Wireless Sensor Networks Based On Ad Hoc

Since the entering of 21st century, with the rapid development of new technology, the multi-disciplinary and cross-cutting area has become a hot research topic. The development and integration of MEMS (Micro-Electro-Mechanical System), wireless communication, embedded system and sensor technology promoted the emergence and development of wireless sensor networks (WSN). WSN are networks of wireless nodes that are deployed over an area for the purpose of monitoring certain phenomena of interest. As a new technology in the field of communication, automation and computer science, it have been researched and applied to many fields including military defense, city management, environment detection and the remote monitor and control of dangerous circumstance. With such background, this paper explores and researches on a wireless sensor network that is easy and quick to construct the networks, smooth to communicate, energy efficient and small.This paper begins with a review of the research on wireless sensor networks and ad hoc technology. After careful analysis of the project requirements, the energy-efficient Zigbee standard is chosen as the basic network protocol and CC2420 is chosen as the wireless transceiver correspondingly, and the application of the wireless sensor network is constructed on it.After a brief introduction of Zigbee standard and CC2420, this paper focuses on several key technologies and problems during the development of the Zigbee stack, such as the data transmitting and receiving with overflow problem in physical layer, the collision avoiding and multi-channel scanning in MAC layer, the broadcast control and route establishing in network layer, and the design of application layer.The Zigbee network security is also realized meanwhile based on the hardware encryption and decryption of CC2420,including the data encryption and node access management. Another important research point of this paper is the energy-efficient improvement of AODV routing protocol, because energy conserving is one of the most important requirements of this project. Based on the summarization of current research achievements, several new strategies are proposed to improve the energy efficiency of AODV, including dynamic transmission power modulation, energy aware route selection, flood control and passive route update, Compared with existing research achievement, our new methods bring in the information of position and network average energy, and are more suitable for the case of our project. The simulations of our new energy efficient strategies under NS-2 demonstrate that the network life could be prolonged by about 37% in best condition.