Research On Wireless Multicast Agent Mechanism Of Live Streaming System In Hybrid Network

The traditional wireless live streaming systems depend on complex networks and many switching devices, which are difficult in implementation and bring high costs. And peer-to-peer based live streaming systems achieve lots of improvements including efficient and stable streaming strategy and QoS (Quality of Service) control method by taking advantage of technologies such as application level multicast and so on. However, peer to peer based live streaming technology ignore the problems in the Implementation of live streaming system in the wireless local area network(WLAN) and fail to propose a proper technology or solution when facing to specific situation in WLAN.By adopting the mechanism of multicast agent based on agent select algorithm and multicast buffer schedule strategy, live streaming systems in hybrid network MoSee tries to multicast media data in wireless network. to solve the problems such as limited bandwidth and node mobility in WLAN, while taking peer-to-peer network as wired network infrastructure.The core idea of multicast agent mechanism is that wireless multicast agent acquires media data from interaction in peer-to-peer network and send the data to other wireless node in WLAN through methods of multicast push and multicast pull. Wireless node requests media data based on emergent area first scheduling strategy, and set maximum request number and interval to avoid too many requests in a short time. Multicast agent sorts time slots based on deadline and request node number first strategy and gets multicast data queue. In the mean time, MoSee proposes two key values to estimate whether a wireless node can be an agent, and adopts an effective mechanism to handle the problem of agent leaving or disabled by selecting a new agent from the rest wireless nodes.Testing between multicast and non-multicast buffering proves that multicast agent mechanism has good feasibility, scalability and excellent prospect. Wireless node working under multicast agent mechanism not only has lower bandwidth usage(60KB/s) than non-multicast one, but also has short starting latency and high buffering ratio. And the implementation of MoSee based on this mechanism proposes an effective solution to pursue live streaming application in WLAN.