Research On Concurrent Multipath Transfer Scheme

In the future, communications network is a heterogeneous network containing a variety of different access technology. It can provide different services to meet different demands of different users. At the same time, with the explosive growth of multimedia data traffic, especially due to the wide application of HD video service, the bandwidth of single network has been unable to meet the demand of HD video transmission, which promotes a research hotspot about how to utilize heterogeneous network resources to realize efficient transmission of video traffic. However, concurrent multipath transfer utilizes multiple network resources to improve resource utilization and data transmission rate, besides, the reliability of data transmission can be improved.Firstly, this thesis introduces concurrent multipath transfer technology and its key problems under heterogeneous networks. In the process of multipath video transmission, one disconnected path leads to the failure decoding at the receiver end. At the same time, Because of the diversity between different links, traditional video transmission can’t adapt the features of different links dynamically. However, SVC encoding technology can transform its bit rate dynamically with the variation of link state, which provides a new idea to concurrent multipath transfer scheme.Secondly, based on SVC and EDCA scheme, it puts forward a concurrent multipath transfer scheme. Because of the mobility of cellular network, the basic layer data is allocated to cellular network, which ensures reliable transmission of the basic layer data. As WLAN has the characteristic of high link rate, the enhancement layer data is allocated to WLAN. On the premise of smooth playback of videos, this method can improve video quality as high as possible. Furthermore, EDCA scheme is applied to ensure important data packet to access channel with high priority in WLAN. The simulation indicates EDCA can reduce packet loss possibility of important data packet and improve its throughput.Finally, relying on the National Science &Technology Major Projects“network control platform and key technology of cooperative multi-terminal in ubiquitous network”, With emphasis on analyzing and designing the single traffic and concurrent multipath transfer scheme based on SVC elastic property, this project realizes the multipath cooperative transmission of video in heterogeneous networks. When the user leaves the coverage area of WLAN, this method can guarantee a low resolution but fluent video relying on the transmission of basic layer data in cellular network. When the user reassociates with WLAN and recovers concurrent multipath transfer, the receiver recombines basic layer data and enhancement layer data to improve video quality, thus, user can enjoy HD video. Moreover, the platform validates the elastic property of SVC and the project acceptance is completed successfully.