From Rateless to Hopless

This paper presents a hopless networking paradigm. Incorporating recent techniques of rateless codes, senders break packets into rateless information streams and each single stream automatically adapts to diverse channel qualities at all potential receivers, regardless of their hop distances. The receivers are capable of accumulating rateless information pieces from different senders and jointly decoding the packet, largely improving throughput. We develop a practical protocol, called HOPE, which instantiates the hopless networking paradigm. Compared with the existing opportunistic routing protocol family, HOPE best exploits the wireless channel diversity and takes full advantage of the wireless broadcast effect. HOPE incurs minimum protocol overhead and serves general networking applications. We extensively evaluate the performance of HOPE with indoor network traces collected from USRP N210s and Intel 5300 NICs. The results show that HOPE achieves 1.7× and 1.3× goodput gain over EXOR and MIXIT, respectively. We further implement HOPE on a sensor network testbed, achieving the goodput gains over CTP.