Fast Retransmission for Concurrent Multipath Transfer (CMT) over Vehicular Networks

In vehicular networks, a vehicle can connect to a nearby Rode Side Unit (RSU) covered by a relay gateway using IEEE 802.11p. When a vehicle communicates with a server, the link between the vehicle and RSU is a wireless link, while the link between the gateway and the server is a wired link. In most cases, packets are lost in the wireless link, not in the wired link. In this paper, we propose fast retransmission made by the Relay Gateway for Concurrent Multipath Transfer (RG-CMT) in vehicular networks. When packets are lost due to error loss or handoff loss in the wireless link, RG-CMT is able to fast retransmit lost packets from the relay gateway to the vehicle. Comparing to fast retransmission made by the server, retransmission made by the relay gateway saves transmission time and bandwidth. The simulation results show that RG-CMT can recover from handoff faster than CMT, and improve the throughput of CMT by 41% when the packet loss rate over the IEEE 802.11p link is 10%.