Location-adaptive network-coded video transmission for improved Quality-of-Experience

Abstract

The recent increase in demand of high quality video applications over satellite channels has led to widespread research in optimal usage of resources to support the user requirements. Particularly, the satellite links are time varying and hence it is beneficial to adapt the rate of transmission across these links by cross-layer optimization techniques (CL). For video applications, it is required to optimize the transmission rate based on providing maximal data rate, for a high definition video, and also maximize the flow continuity of the video, thereby providing minimal freezing of the video during playback. The Quality of Experience (QoE) driven Cross-layer optimization [1], for point-to-point data transmission across satellite networks is one such example of optimizing the video perceived by the user. Another aspect of the satellite systems is the use of satellites as a relay in communication networks. The natural advantage of satellites of covering a huge geographical region leads to a high ubiquity in satellite services, which is particularly advantageous for video transmission. Although use of satellite as a relay between geographically separated terrestrial terminals is imperative, but the same satellite is used as a relay for multiple terminal pairs simultaneously. This leads to multiplexing of resources for transmission at the satellite relay node. This gives the opportunity of network coding at the relay node. A number of recent advances in the field of network coding (NC) have established it as an efficient routing mechanism which can achieve multicast capacity [2]. Implementation of network coding in satellites has also been studied in [3]. The use of NC with CL techniques is imperative to the new generation technologies and has been studied in [4, 5]. In our previous work [6], we have also explored the joint implementation NC with CL over satellite channels. The network coding opportunities are highly maximized with maximal overhearing of unintended packets at different nodes [7]. Otherwise termed as interference, an intelligent treatment of these overheard packets, can lead to an efficient resource utilization [8]. This overhearing is dependent upon the geographical location of the different user terminals [9]. Therefore, the geographical location of users should be considered in order to implement network coding in satellite services [10]. Inspired by these works, in this paper, we present a joint implementation of QoE-driven cross layer optimization and network coding while taking into account the geographical distribution of users in such a way, that the joint scheme improves the overall QoE of the end-user while optimizing the resource utilization. Our work not only admits a flexibility of supporting heterogeneous user demands in terms of video quality, but also allows a uniform maximization of video quality in terms of both clarity and continuity. We consider both the location as well as demand of the user to