Research On Wireless Multimedia Sensor Network MAC Protocol Based On Differentiated Services

Wireless multimedia sensor network is a new type of sensor network pursuing a varietykinds of sensing information.Through the introduction of multimedia sensor nodes, it cancapture multimedia information such as audio, video, images and so on. Because of there aremany kinds of data packets in the network, MAC protocol should be able to providedifferentiated services during competing and accessing the channel to different types of packets,prioritize the access request of high-priority packet. In this paper, it mainly researches thewireless sensor network MAC protocols, focuses on DCF channel access and backoff, andraises Non-equal probability competitive method.Study of DCF's channel access method and backoff mechanism shows that it can't providedifferentiated services so that all packets fairly compete the use of channel. In order to solvethis problem, a new algorithm is proposed based on non-equal probability competitive. Usingdifferent backoff strategies, it makes high-priority packets have smaller backoff window andwin the channel access with larger probability.Taking into account the fairness issue of ordinarypackets, by introducing two parameters reflect the current channel load conditions and theurgency of the request, a new MAC protocol using variable parameters to dynamic adjustmentthe backoff window is proposed based on the NEPC algorithm. According to the comparison ofthe current channel load value and the best value, it can determine the network congestion level,and use the corresponding parameters to modify the backoff window.The simulation results can be seen that the MAC protocol based on NEPC can achievedifferentiated services based on packet type.Through two floating parameters, it maximumreduces the ordinary packet's backoff delay, improves the competitive disadvantage caused byrepeated backoff.