Wireless Video Broadcasting to Diverse Users

Abstract

The growing diversity in media clients calls for content providers to adapt media content to adhere to their various needs. It is desirable to serve these heterogeneous users in a fast and efficient manner. Scalable media, such as H.264/MPEG-4 SVC, helps make this possible. To account for various viewing capabilities of each user, such as different spatial or temporal resolutions, the Multiple Distortion Measures framework is used [1], [2]. MDM associates multiple distortion values with each packet depending on the user types (low/high resolution viewers, low/high frame rate viewers, etc.) who will consume the media packets. In this paper, we examine how to broadcast media packets with multiple distortion measures to multiple users. The tradeoff between media distortion and delay (in the form of retransmissions) plays an integral role in the scheduling decision. We cast the problem as a stochastic shortest path problem and use Dynamic Programming to find the optimal policy. In the case of statistically static channels, the optimal policy is shown to be a threshold policy where the number of allowable retransmissions is dictated by the importance, in terms of incurred distortion, of each packet. Through experimental results, we show that our policy, which considers multiple distortion measures, achieves up to 8dB gains over conventional approaches. Finally, a policy based on the theoretical results of statistically static channels is empirically shown to have high performance for time-varying channels modeled by a two-state Markov Chain.

The Effects of Priority Levels and Buffering on the Statistical Multiplexing of Single-Layer H.264/AVC and SVC Encoded Video Streams

“…For instance, adaptations for the transport layer using bandwidth estimation and congestion control mechanisms have been explored in [6]- [9]. Adaptations to the wireless channel through intelligent scheduling policies have 0018-9316/$26.00 © 2010 IEEE been studied in [10]- [15]. Network coding techniques that divide the video packets into separate channels and apply unequal error protection have, for instance, been examined in [16], [17].…”

Broadcast video streaming in cellular networks: An adaptation framework for channel, video and AL-FEC rates allocation

“…In advanced wireless technologies such as 3GPP/LTE [1], [2], broadcast video streaming is considered to be one of the most important applications that need to meet the requirements and capabilities of a wide range of mobile devices, with respect to available computing resources, power consumption, spatial resolution of the screen, rate, etc. Scalable Video Coding (H.264/SVC) [3] supports heterogeneous devices and users with different channel conditions by allowing a source (server) to send a video with scalability provided in either the temporal, spatial, or quality domain [4]. In order to provide protection to the video packets against losses, several FEC techniques have been proposed for broadcast scenarios.…”

Scheduling algorithms for broadcasting media with multiple distortion measures

“…Our work differs from these in that we consider the unique properties of media communications where packet/frame importance varies between frames and even across users. This work is similar in flavor to [13] and [14]. In [13], backlog is used as a measure of the time until the transmission session completes and the transmission buffer is emptied.…”

“…In the case of periodic video traffic, this corresponds to the average delay of each frame. In contrast to [14], we provide a more in depth look into the optimal scheduling policy and further study the tradeoff between the distortion and delay. In this paper, we introduce a knob to tune for a precise target frame rate.…”