A Simple LTE-R Resource Allocation Scheme for Relay-Assisted Railway Communications

In this paper, we consider a multi-carrier railway communication scenario, where each train wagon is equipped with a single cooperative relay for quality of service (QoS) enhancement. For a classic Long-Term Evolution for Railways (LTE-R) resource allocation problem in the context of railway communications, we propose a low-complexity resource allocation scheme by the dimension reduction of cost matrix, aiming to maximize the number of clients properly served in the cabin by a minimum amount of energy consumption. The proposed scheme can produce near-optimal solutions compared to the optima returned by the extensive search over the entire solution space. As a key advantage of the proposed scheme, the computational complexity is greatly reduced, leading to a much faster LTE-R resource allocation process than that of the optimal benchmark. Such an advantage well satisfies the real-time service demands of users traveling through high-speed railway (HSR) when the network topology and wireless environment could drastically vary over a short period of time (100-500 ms). We carry out extensive simulations to verify the effectiveness and efficiency of the proposed LTE resource allocation scheme for relay-assisted railway communications.