Ultra Low Latency Video Streaming

World's first remotely driven bus

10 June 2022


Remote Control Bus

Soliton has demonstrated the first remotely controlled bus in Japan without a driver in the driver’s seat. This incredible break-through has come about by the development of ultra-low latency live streaming over cellular. Live streaming over 3G, 4G and 5G is nothing new, but typically this would involve a delay of a few seconds. This delay could prove fatal if the same technology were used to remotely control a vehicle. A driver needs to experience the road in almost real time and any reactions by the driver to the control of the bus should be immediate in real-time, especially in an emergency situation.

Remote driving is different to autonomous driving. A driver in a remote location with Soliton technology can drive the bus with a delay of less than 65ms (0.065seconds) which is safe to operate the bus at speeds within the city limit. The driver is in total control of the bus – there is no Lidar technology (a radar collision detection system) that an autonomous driving system would use.

The applications for this are numerous. When staff are in short supply and driving can be outsourced, or as a back-up strategy for autonomous driving when their logic becomes confused are all examples. Remote driving can be used in natural disasters or military situations where people should not be put in harms way.

The technology behind the ultra low latency live streaming is with the Zao range of mobile HEVC video encoders from Soliton. The Zao-X can bond together multiple 4G and 5G connections for reliability and bandwidth, but it is their new RASCOW2 streaming protocol that is the major innovation. In conjunction with an H.265 encoding codec for compression, has been designed to operate over unstable cellular networks with parallel processing to reduce overall latency. The 65ms quoted latency includes the camera, encoding and decoding latency, the mobile network, and the latency of the monitor that views the live stream remotely. This is known as a glass-to-glass latency from camera to monitor. It is a combination of the low latency technology and exceptional reliability of the streaming that makes the remote control of a bus a safe option for deployment by utilizing Soliton technology.