基于随机线性网络编码和UDP的可靠低时延传输方法

针对传输控制协议（transport control protocol，TCP）在无线通信中吞吐量受到丢包和反馈时延影响严重的问题，提出一种结合随机线性网络编码（random linear network coding，RLNC）和用户数据报协议（user datagram protocol，UDP）的可靠低时延无线通信传输方法。分别考虑一般RLNC和降低了编译码复杂度及头部开销的稀疏RLNC，原型实现了（稀疏）RLNC的编码、再编码、译码模块；并通过ns-3网络仿真在两跳有损中继链路中将所提方法分别与TCP和快速UDP网络连接（quick UDP internet connections，QUIC）协议的传输完成时间进行对比。仿真实验结果表明，在较高丢包率链路中，所提结合RLNC的UDP传输显著降低了传输完成时间。通过选择适当的编码参数，稀疏化的RLNC在链路条件较好的环境中能够进一步降低RLNC的传输时间，但在高丢包率环境中其传输完成时间高于RLNC。

Reliable Low-Latency Wireless Transmissions Based on Random Linear Network Coding and UDP

In this study, a scheme combined the random linear network coding (RLNC) with user datagram protocol (UDP) is proposed to achieve reliable low-latency wireless communications, so as to address the low-throughput issue of transport control protocol (TCP) caused by the packet losses and delayed feedback. Both of the original and the sparse RLNC are considered, in which the latter is to reduce the computational complexity of encoding/decoding and the header overhead. To investigate the performance, the encoding/recoding/decoding functionalities of the (sparse) RLNC are implemented. Network simulations using ns-3 are conducted to compare the completion time of the proposed scheme with that of using TCP and QUIC (quick UDP internet connections) in a two-hop lossy relay link. The results show that the proposed scheme can achieve much lower completion time in highly-lossy scenarios. It is revealed that the sparse RLNC with proper coding parameters can reduce the completion time of the original RLNC if the link conditions are good, thanks to its lower header overhead. However, the original RLNC performs better if the conditions are poor.