Priority-based Slow Start Back-off Algorithm In WMSN

Compared to traditional wireless sensor networks, Wireless Multimedia Sensor Network (WMSN) is more effective at accurate information collection, and fine-grained environmental monitoring capacity. Currently, wireless multimedia sensor networks have enhanced traditional applications variously. WMSN for supplies in emergency hospital and personnel management system has emerged with the research of WSN application in normal hospital. Different from ordinary medical systems, emergency hospitals are provided with special environment and conditions:1) Health equipment is very expensive;2) Sorts of supplies and equipment are of huge quantity;3) meticulous management is difficult. Under these conditions, to cope with congestion problems WMSN for emergency hospitals requires greater network throughput, higher capacity for real-time data transmission and more computing power of computing components. So it is essential to reduce delay and jitter in multimedia information transmission, improve throughput and lower latency network congestion control of WMSN in emergency hospital environment.This article is intended for project "The research and implementation of tracking assets and materials in emergency hospital and location system based on RFID" and proposes a multi-level priority mechanism to deal with congestion problem in the system. This mechanism improves the transmission of wireless multimedia sensor networks in fairness, throughput and latency. The main contents and innovations are as follows:(1) Propose a Priority-based slow-start backoff algorithm in WMSN. For the widely application of802.11DCF Algorithm the WMSN networks, we provide a solution, which is based on dynamic assignment congestion window, to the problems of priority crosstalk, supporting WMSN, and provide better adaptability to load traffic. The sed back-off algorithm can reduces collision rate and saturation delay, meanwhile, keeps the same performance in saturation throughput.(2) Propose a Cross-layer congestion control strategy for WMSN. Since in layered protocol congestion control lack of support of throughput indicators. We integrate the communication layers, which disposed in layered protocol, into a single module. Using initiative determination, receipt based on contention, local congestion control, and distributed duty cycle operation to realize efficient and reliable communication. This mechanism improved throughput while reduced average energy consumption per packet when keeps the same performance in saturation delay.In this article, we apply the multi-level priority mechanism congestion control algorithm to the emergency hospital. And this strategy will improve health care efficiency of the hospital, meanwhile, reduce the casualties in accident.