On services pushing and caching in high-speed train by using converged broadcasting and cellular networks

This paper proposes a services pushing and caching algorithm in high-speed train (HST) by using converged wireless broadcasting and cellular networks (CWBCN). Services pushing and caching on the HST is an efficient way to improve the capacity of the network; and it can also lead to better user experience. In the proposed services pushing and caching model, the most popular services are delivered and cached on the vehicle relay station (VRS) of the train ahead the departure time. Then, the most popular services are broadcasted and cached on the User Equipments (UEs) after all the passengers are on the train; the less popular services are transmitted to the user by p2p mode by the relayed cellular network on the train. In order to maximize the network capacity in limited time slots, we transform the issue into the 0–1 Knapsack problem. Dynamic programming algorithm is adopted to solve it in polynomial time. As the passengers may get on or get off the train when pushing the most popular services, an information retransfer algorithm is also proposed when more intermediate stations are considered. Simulations show that the proposed algorithms can efficiently improve the capacity of the converged network.