Performance of Remote Unit Collaboration Schemes in High Speed Train Scenarios

In this paper, we investigate the impact of various remote unit collaboration schemes on the transmission performance to passengers, traveling in high speed trains. We assume that the user equipments directly communicate with the remote units, i.e., the trains are not equipped with relay nodes. We introduce a theoretical model based on Maximum Ratio Transmission and Gamma distributed fading, and analyze a representative segment of a railroad track. Results from both, theory and simulations by the Vienna LTE-A System Level Simulator are provided in terms of train average spectral efficiency and allow us to discuss the suitability of the moving cell concept for trains without relay support. Our theoretical results exhibit an offset from the simulations. Investigating its origin reveals the limitations of codebook-based precoding and allows us to adapt our theoretical model for accurate performance predictions.