A Construction And Research On Adaptive Adjustment Problem Of Mobile Terminal High-Performance Application Layer Multicast System

With continuous innovation of mobile 3G/4G communication technology and the growing popularity of Wi-Fi hotspots, exponential growth of mobile video Application subscribers, makes mobile video services in concurrency, scalability, reliability, interactivity, and cross-platform portability faced a huge challenge.Although intelligent terminals are easy to carry and have strong mobility, in a mobile network environment they are not stable, the network topology changing more frequently, have lower reliability and service quality, but video services have higher requirement in network throughput, propagation delay and real-time etc. Therefore, how to effectively combine the two to improve the speed of data distribution, allowing mobile users to obtain sustainable and efficient video services become an urgent problem.The appearance of application layer multicast technology makes up for the shortcomings of the two, it uses "End-to-End Argument" ideology, by the end hosts forming an overlay network and undertaking the task of receiving and forwarding data, shifting the data forwarding tasks undertaken by intermediate network devices originally to intelligent terminal to implement. Compared with the traditional IP multicast, application layer multicast is easy to deploy and implement, but its structure is only limited to the application layer, can not detect the underlying physical network topology, and limited processing power of intelligent terminals, resulting in obvious lack of stability and multicast efficiency and other aspects. Therefore, how to build a high-performance ALM system in the mobile environment, providing a sustainable and efficient multicast service for mobile users has become the main purpose of this paper.Based on the above purpose, by carefully analysis and research of a large number of the relevant literatures of application layer multicast, this paper proposes a high-performance construction scheme of application layer multicast video playback system. The scheme analyzes, designs and implements the main function modules of the system server and client in detail, and uses third-party multimedia framework AnyChat to resolve the problem of audio and video codecs as well as data transmission in intelligent terminal equipment, and in order to alleviate the pressure of database owing to the large-scale multicast request, the intermediate layer data buffer is designed to improve concurrency, stability and efficiency of the server. In order to solve the problem of instability of the application layer multicast system owing to the highly dynamic nature of intelligent terminal equipment, the paper establishes a problem model of adaptive adjustment, proposes a method of automatically adjusting the multicast tree’s structure according to the level of intelligent terminal equipments overall performance to optimize the multicast performance to ensure that mobile users can obtain the clear, smooth, stable and efficient video services.