Network Coded Repetition: A Method to Recover Lost Packets in Vehicular Communications

Rapidly repeating the original packet multiple times has been found to improve the probability of successful reception of a packet in error-prone vehicular communication environment. However, since each repetition increases channel load, performance of repetition-based loss recovery starts to deteriorate with increasing number of vehicles on the road. This paper explores the benefit of Network Coding in improving the performance of repetition-based loss recovery for vehicular safety communications. A simple network coded repetition scheme is proposed, which combines (XORs) packets from close-by neighbours and repeats the XORed packets instead of original packets, thereby creating the possibility of an increased number of packet recovery per repetition. An analytical study is conducted to evaluate the performance of the proposed network coded repetition, which is validated by simulation experiments. Conditions under which network coding can outperform the original repetition scheme are discussed.