Improving QoS on high-speed vehicle by multipath transmission based on practical experiment

With the boom of modern high-speed vehicles and various wireless technologies, providing stable and high-quality Internet services on board is becoming a rising trend for both passengers and operators. However, a major challenge is that the vehicle-to-ground communication links may suffer from insufficient bandwidth, long round-trip time, and high packet loss rate. Although multiple wireless networks, such as WiFi, 3G and 4G, may be available along the track, onboard users can hardly have a good experience if they can only visit the Internet via one wireless network because of the limitation of the user devices, e.g. laptops with WiFi. The wireless network supported by a device may be subjected to coverage gaps and signal attenuation. In this paper, we first measure the link qualities of multiple existing 3G and 4G technologies, which are candidates for the vehicle-to-ground communication, in a typical high-speed environment on high-speed trains in China. Then, a concurrent multipath transmission scheme is proposed, which provides transparent and effective Internet services for the users through multiple available wireless technologies, without requiring the participation of the user devices in any multipath signaling. Experiments show that the scheme can improve QoS (Quality of Service) of Internet on board by increasing the available bandwidth and reducing the packet loss rate.