Packet loss recovery in wireless broadcast is challenging, particularly for real-time applications which have strict and short delivery deadline. To recover the maximum number of lost packets within a short time, existing packet recovery solutions often rely on instantly decodable network coding (IDNC). Some of these solutions can recover nearly the maximum number of lost packets possible at the cost of collecting feedback from all (or a large percentage of) users. This is impractical in dense networks. In addition, their runtime grows with the number of users, which is not desirable due to the urgent delivery deadline of real-time applications. In this work, we introduce random instantly decodable network coding (RIDNC), a random encoding approach to IDNC. We propose RAndom IDNC Encoder (RACE), a fast RIDNC encoder that can recover nearly as many lost packets as the optimal RIDNC encoder. We compare RACE with the CrowdWiFi encoder, a high performing packet loss recovery solution used in CrowdWiFi, a commercial system for broadcasting live video in dense networks. We show that RACE is up to two orders of magnitude faster than the CrowdWiFi encoder, and recovers more lost packets in practice, where there is not enough time to collect feedback from many users.

中文翻译：

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密集无线网络中实时应用广播中的丢包恢复


无线广播中的丢包恢复具有挑战性，特别是对于具有严格且短的交付期限的实时应用。为了在短时间内恢复最大数量的丢失数据包，现有的数据包恢复解决方案通常依赖于即时可解码网络编码（IDNC）。其中一些解决方案可以恢复几乎最大数量的丢失数据包，但代价是收集所有（或大部分）用户的反馈。这在密集网络中是不切实际的。此外，它们的运行时间随着用户数量的增加而增长，由于实时应用程序的交付期限紧迫，这是不可取的。在这项工作中，我们引入了随机即时可解码网络编码（RIDNC），这是一种 IDNC 的随机编码方法。我们提出了 RANdom IDNC 编码器（RACE），这是一种快速 RIDNC 编码器，可以恢复与最佳 RIDNC 编码器几乎一样多的丢失数据包。我们将 RACE 与 CrowdWiFi 编码器进行比较，后者是 CrowdWiFi 中使用的高性能丢包恢复解决方案，CrowdWiFi 是一种在密集网络中广播实时视频的商业系统。我们表明，RACE 比 CrowdWiFi 编码器快两个数量级，并且在实践中恢复更多丢失的数据包，而在实践中没有足够的时间收集许多用户的反馈。