Playback continuity driven cross-layer design for HTTP streaming in LTE systems

In this paper, a playback continuity driven cross-layer design is proposed for HTTP streaming in LTE systems in which the stringent delay deadline of the application layer is translated into the transmission capacity requirement at the MAC layer of eNodeB. First the client buffer information such as the fullness of the buffer and the playback information is easily obtained at the client. Based on the buffer information, the continuous playback time interval that the completely received segments in the client buffer can support is calculated. To keep continuous playback, the remaining packets of the un-completely received segment should arrive at the client during the time interval. Considering the video information in MPD from the HTTP server and the buffer information about the un-completely received segment, the sum size of the remaining packets in MAC queue can be obtained. From the time interval and the sum size, the transmission rate requirement that the MAC layer should satisfy can be acquired. For a scheduling period with fixed duration called TTI, the transmission capacity at the MAC layer can be easily acquired. Then a new mathematical model is proposed to maximize the system throughput subject to the transmission capacity requirements of the clients and the total RB constraint of the physical layer. Then a resource allocation scheme with low complexity is developed to solve the proposed problem. Simulation results show that the proposed algorithm can efficiently improve the playback continuity compared with other existing algorithms.