Improving Research On The Flooding Algorithm For Low Frequency Wireless Sensor Networks

Wireless sensor networks concerned as it is developed, is widely applied in various fields. Especially in recent years, with the rapid development of micro-sensor technology, microelectronic technology and RFID technology, wireless sensor networks is used in military, aerospace, national security and other fields. As one of the representatives of the 21 st century cutting-edge technology, wireless sensor network shows a broad application space in the future.Wireless sensor networks is a network architecture which is composed of cheap tiny sensor nodes. Sensor nodes communicate with each other through radio. Because of the node’s energy is limited and works in very bad environment, how to reduce the nodes’ energy consumption and maximumly extend the network’s lifetime is a key issue in the study of wireless sensor networks.Media Access Control(MAC) Protocol is the most important part in the wireless sensor networks’ system. It directly decides how to use its energy and allocates the limited communication resource among sensor nodes. S-MAC is a typical MAC protocol for wireless sensor networks that adopt sleep-wake up mechanism. In S-MAC, the sensor nodes are put to sleep periodically to save energy. As the working frequency is fixed in such protocol, the network throughput will degrade under heavy traffic, but unnecessary energy consumption will occur while under light loads. This thesis focuses on the research of Flooding’s MAC protocol in low duty cycle wireless sensor networks and designs a new MAC protocol for WSN, which is called Adaptive Duty Cycle MAC Protocol(ADC-MAC). The main contents are as follows:First of all, combined with the queuing theory, we get the modeling of sensor nodes and then propose a novel scheme with adaptive duty cycle. This scheme can change the node’s duty cycle based on the network’s traffic. Second, this thesis proposes a dynamic backoff algorithm for wireless sensor networks, which is called Adaptive Avoid Collision(AAC). AAC can automatically adapt to network flow and the change the node’s access channel capacity, which can effectively avoid second collision. Analysis and simulation results show that the improved protocol effectively improves the network throughput, reduces energy consumption. We can conclude from the results that the new protocol achieves its design goal.