A survey on advanced transmission technologies for high bandwidth and good signal quality for high-speed railways

A high-speed railway (HSR) has gained very high popularity for passengers due to the fast, reliable, economical and convenient during traveling a very long-distance journey. The demand for advanced broadband services such as watching 4K movies, cloud computing and online gaming, has exponentially increased for travelers on the high-speed train (HST). The HST can't provide good bandwidth to facilitate these services for travelers via existing technologies such as cellular networks and satellite networks because of frequent handoffs, high penetration and fading. So, the bandwidth degrades dramatically due to these issues. Research workers have developed proposals to handle these problems by advanced transmission technologies for HSR. Until now, various transmission schemes have been suggested by research works with the focus for either high bandwidth or signal quality improvement. This paper presents a survey on advanced transmission technologies for high bandwidth and good signal quality. In this paper, a comprehensive survey of the appropriate literature published that concentrate on advanced transmission methods in HSR communications in getting higher bandwidth efficiency and maximize the signal quality is presented. Advanced transmission method can be categorized into orthogonal frequency division multiplexing (OFDM), multiple-input multiple-output (MIMO) and radio-over-fiber (RoF)