Zuhra Sadaf Ul, Besser Karl-Ludwig, Chaporkar Prasanna, Karandikar Abhay, Poor H Vincent
Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ 08544, USA.
Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
Entropy (Basel). 2023 Jul 11;25(7):1045. doi: 10.3390/e25071045.
In video streaming applications, especially during live streaming events, video traffic can account for a significant portion of the network traffic and can lead to severe network congestion. For such applications, multicast provides an efficient means to deliver the same content to a large number of users simultaneously. However, in multicast, if the base station transmits content at rates higher than what can be decoded by users with the worst channels, these users will experience outages. This makes the multicast system's performance dependent on the weakest users in the system. Interestingly, video streams can tolerate some packet loss without a significant degradation in the quality experienced by the users. This property can be leveraged to improve the multicast system's performance by reducing the dependence of the multicast transmissions on the weakest users. In this work, we design a loss-tolerant video multicasting system that allows for some controlled packet loss while satisfying the quality requirements of the users. In particular, we solve the resource allocation problem in a multimedia broadcast multicast services (MBMS) system by transforming it into the problem of stabilizing a virtual queuing system. We propose two loss-optimal policies and demonstrate their effectiveness using numerical examples with realistic traffic patterns from real video streams. It is shown that the proposed policies are able to keep the loss encountered by every user below its tolerable loss. The proposed policies are also able to achieve a significantly lower peak SNR degradation than the existing schemes.
在视频流应用中，尤其是在直播活动期间，视频流量可能占网络流量的很大一部分，并可能导致严重的网络拥塞。对于此类应用，多播提供了一种将相同内容同时传送给大量用户的有效方式。然而，在多播中，如果基站以高于信道最差的用户所能解码的速率传输内容，这些用户将会出现中断。这使得多播系统的性能依赖于系统中最弱的用户。有趣的是，视频流可以容忍一定程度的丢包而不会使用户体验到的质量显著下降。可以利用这一特性通过减少多播传输对最弱用户的依赖来提高多播系统的性能。在这项工作中，我们设计了一种容错视频多播系统，该系统允许一定程度的可控丢包，同时满足用户的质量要求。具体而言，我们通过将多媒体广播多播服务（MBMS）系统中的资源分配问题转化为稳定虚拟排队系统的问题来解决该问题。我们提出了两种损失最优策略，并使用来自真实视频流的具有实际流量模式的数值示例来证明它们的有效性。结果表明，所提出的策略能够使每个用户遇到的丢包保持在其可容忍的丢包之下。所提出的策略还能够实现比现有方案显著更低的峰值信噪比下降。
