CUHK Passions and Pursuits

47 Special Delivery in a Smart City Cities get smarter with Raymond Yeung’s network-coding theory D espite common mis- conception, data are not in fact a contiguous commodity. They can be broken apart, rearranged and transformed instead of being shipped ‘all in one go.’ The information is disseminated through the system, then reassembled, a more-efficient and more-reliable way of making sure it makes it to its ultimate destination. Such a system of transmission is called BATS, or BATched Sparse code, developed by Prof. Raymond Yeung in 2011. It is a network-coding scheme that’s practical and efficient to implement, and has subsequently been refined and developed for commercial applications. To use the mail analogy, he explored the ability of the nodes transmitting data not simply to forward packets along, but to open them and rearrange the contents into other packets, which could be recombined at the final destination. Hong Kong could benefit from his discovery with the development of ‘smart lampposts’. These lampposts will, if all goes well, contain a multitude of sensors that could better coordinate the traffic light in the vicinity, detect environmental factors such as pollution, and gather analytics to allow for better city planning. By becoming their own small signal-broadcast posts, lampposts could also allow for territory-wide WiFi coverage, as well as allowing autonomous cars to communicate with the system and with other cars. The system could be a fast and efficient way of introducing 5G telecommunications to the city. The 5G technology is one order better in terms of bandwidth and latency than the existing 4G systems. But it operates at a very high frequency, meaning it is easily blocked by objects and barriers in its directional transmission. Having broadcast points throughout the city would allow for universal transmission. Professor Yeung’s BATS technology could allow for a small number of the lampposts to connect to the network by fibre, as nodes, while the others communicate to each other using BATS technology. By cutting data loss to negligible levels with BATS, large ‘multi-hop’ leaps are possible between posts communicating to each other, reducing the need for wired lampposts feeding into the network substantially. The government is planning a pilot project with 400 lampposts around the city. They will track weather, environmental data, transportation information and crowd flows. The idea is to equip them with WiFi and 5G capability, to improve communications service across the territory. They could also act as digital street signs, providing pedestrian and traffic directions, and indicate local parking conditions. Packet Loss Rate: 0.2 File Size: 16 Fountain code BATS code batch buffer batch buffer batch buffer received: 8 received: 0 File Decoded generate batch generate packet