Heterogeneous traffic scheduling in downlink high speed railway LTE systems

This paper concentrates on the problem of how to schedule a great quantity of heterogeneous traffic for one mobile node in LTE. To solve such problem in High Speed Rail (HSR), we present a decoupled time/frequency domain packet scheduler based on the analysis of HSR MIMO channel properties. In time domain, a novel single-user adaptive EXP/PF algorithm is adopted. In frequency domain, a fast exhaustive search-based frequency resource allocation algorithm (FRAA) named SU-OP is proposed, which can utilize the scarce frequency resources with constraint of LTE practical limits. Furthermore, we also introduce an alternative FRAA named SU-Greedy which has lower complexity and could obtain similar performance while the SNR is not high. By our original calculation rule the complexity of both algorithms is reduced further and thus more practical. Based on the system simulation, we find that the proposed scheduler has better delay and throughput performance than the well-known joint time domain and frequency domain proportional fair (TD-FD-PF) scheduler under HSR scenario.