High-Speed Railway Wireless Communications: Efficiency Versus Fairness

Abstract

High speed railways (HSRs) have been deployed widely all over the world in recent years. Different from traditional cellular communication, its high mobility makes it essential to implement power allocation along the time. In the HSR case, the transmission rate depends greatly on the distance between the base station (BS) and the train. As a result, the train receives a time varying data rate service when passing by a BS. It is clear that the most efficient power allocation will spend all the power when the train is nearest from the BS, which will cause great unfairness along the time. On the other hand, the channel inversion allocation achieves the best fairness in terms of constant rate transmission. However, its power efficiency is much lower. Therefore, the power efficiency and the fairness along time are two incompatible objects. For the HSR cellular system considered in this paper, a trade-off between the two is achieved by proposing a temporal proportional fair power allocation scheme. Besides, near optimal closed form solution and one algorithm finding the ǫ-optimal allocation are presented. Index Termshigh speed railway communication, power allocation, channel service, proportional fairness along time.This paper has been published by IEEE Trans. on Veh.

Channel Measurements and Models for High-Speed Train Communication Systems: A Survey

“…Mobile broadband performance experiences from regional HSTs were investigated in [128] by monitoring the fluctuation of system throughput caused by the varying distance between the BS and HST, multi-path fading and co-channel interference conditions. A temporal proportional fair power allocation scheme for HST wireless communication systems has been proposed in [129]. The proposed scheme is designed to achieve a tradeoff between power efficiency and fairness along the time.…”

Performance analysis of high‐speed railway communication systems subjected to co‐channel interference and channel estimation errors

“…Upon substituting the PDF of the random variables X and Y into (6), the PDF of λ may be expressed as…”

“…With the drastic increase of train speeds, the handovers will occur more and more frequently, which potentially further degrades the achievable performance seriously. Furthermore, the energy efficiency and the fairness of high-speed railway communication systems have been considered in [5,6]. It is argued that the most efficient power allocation will assign all the power, when the train is nearest to the FS, which may impose a substantially great unfairness as a function of the time Q1 .…”

When is it optimal for the event-triggered strategy in energy harvesting transmission

“…From the view of practical applications, [3,[17][18][19][20][21] consider the moving agent when energy harvesting happens. When the energy harvested from environment is consecutive, channel service becomes a more suitable performance metric as [19] considered.…”