No abstract

HTTP based adaptive video streaming has become a popular choice of streaming due to the reliable transmission and the flexibility offered to adapt to varying network conditions. However, due to rate adaptation in adaptive streaming, the quality of the videos at the client keeps varying with time depending on the end-to-end network conditions. Further, varying network conditions can lead to the video client running out of playback content resulting in rebuffering events. These factors affect the user satisfaction and cause degradation of the user quality of experience (QoE). It is important to quantify the perceptual QoE of the streaming video users and monitor the same in a continuous manner so that the QoE degradation can be minimized. However, the continuous evaluation of QoE is challenging as it is determined by complex dynamic interactions among the QoE influencing factors. Towards this end, we present LSTM-QoE, a recurrent neural network based QoE prediction model using a Long Short-Term Memory (LSTM) network. The LSTM-QoE is a network of cascaded LSTM blocks to capture the nonlinearities and the complex temporal dependencies involved in the time varying QoE. Based on an evaluation over several publicly available continuous QoE databases, we demonstrate that the LSTM-QoE has the capability to model the QoE dynamics effectively. We compare the proposed model with the state-of-the-art QoE prediction models and show that it provides superior performance across these databases. Further, we discuss the state space perspective for the LSTM-QoE and show the efficacy of the state space modeling approaches for QoE prediction.

A rapid increase in the video traffic together with an increasing demand for higher quality videos has put a significant load on content delivery networks in the recent years. Due to the relatively limited delivery infrastructure, the video users in HTTP streaming often encounter dynamically varying quality over time due to rate adaptation, while the delays in video packet arrivals result in rebuffering events. The user quality-of-experience (QoE) degrades and varies with time because of these factors. Thus, it is imperative to monitor the QoE continuously in order to minimize these degradations and deliver an optimized QoE to the users. Towards this end, we propose a nonlinear state space model for efficiently and effectively predicting the user QoE on a continuous time basis. The QoE prediction using the proposed approach relies on a state space that is defined by a set of carefully chosen time varying QoE determining features. An evaluation of the proposed approach conducted on two publicly available continuous QoE databases shows a superior QoE prediction performance over the state-of-the-art QoE modeling approaches. The evaluation results also demonstrate the efficacy of the selected features and the model order employed for predicting the QoE. Finally, we show that the proposed model is completely state controllable and observable, so that the potential of state space modeling approaches can be exploited for further improving QoE prediction.

No abstract

Video streaming in mobile environments has always been challenging due to various factors. The time-varying wireless channel, limited and shared transmission resources, fluctuating network conditions between the video server and the end user etc. greatly affect the timely delivery of videos. Given these factors, it is important that the wireless networks perform optimal allocation of resources and cater to the demands of the video streaming users without degrading their quality-of-experience (QoE). Modeling streaming QoE as perceived subjectively by the users is non-trivial, and in general a complex task, as it is continuous, dynamic, and time-varying in nature. The continuous perceptual QoE degradation due to network induced artifacts such as time-varying video quality and rebuffering events has not been considered in the literature for resource allocation (RA). In this paper, we propose Video Quality Aware Resource Allocation (ViQARA), a perceptual QoE based RA algorithm for video streaming in cellular networks. ViQARA leverages the strength of the latest continuous QoE models and integrates it with the generalized α-fair strategy for RA. Through extensive simulations, we demonstrate that ViQARA can provide significant improvement in the users perceptual QoE as well as a remarkable reduction in the number of rebufferings when compared to existing throughput based RA methods. The proposed algorithm is also shown to provide better QoE optimization of the available resources in general, and especially so when the cellular network is resource constrained and/or experiences large packet delays.