A Random Linear Network Coded HARQ Solution for Lossy and High-Jitter Wireless Networks

Abstract

Time-sensitive applications on wireless networks often demand high reliability and high throughput. Random Linear Network Coding (RLNC) is a forward error correction (FEC) method for wireless lossy channels that organizes the information in blocks, commonly called generations. Hybrid Automatic Repeat reQuest (HARQ) is a combination of a FEC method, such as RLNC, and an ARQ often used to ensure reliable data transmission. Many RLNC-based protocols provide in-order delivery, which helps in general cases but backfires in high-jitter channels. Multigeneration RLNC protocols are more resilient in high-jitter channels than conventional RLNC protocols because they are capable of handling multiple generations at the same time. However, they still struggle against losses. Despite the considerable amount of research done in this field, there is still no solution that combines HARQ with multigeneration RLNC protocols. Our contribution in this paper is two-fold: (i) we propose a new ARQ mechanism adapted for multigeneration RLNC protocols, and (ii) we compare its performance in terms of per-packet delay and throughput to conventional RLNC, HARQ RLNC, and multigeneration RLNC. The results show an increase in the decoding probability from 25% without ARQ to 80% with ARQ. Moreover, we observe a decrease of 35% in the average packet delay.