Distributed antenna system based frequency switch scheme evaluation for high-speed railways

Abstract

Abstract-High-speed railway (HSR) has witnessed a huge growth globally, and now is reaching a maximum speed of 575 km/h. This record of speed makes mobile communications difficult for HSR since the handover (HO) frequency increases which results in a high loss of connectivity. Based on distributed antenna systems (DASs), this paper utilizes the two-hop network architecture for HSR broadband wireless communication systems. With the target of achieving high system capacity, superior transmission reliability, and consequently high-quality broadband wireless communication service for passengers in HSR. Moreover, a Frequency Switch (FSW) scheme is proposed for the two-hop network architecture to alleviate the frequent HO issue in traditional HSR wireless communication systems where HO generally happens between the successive remote antenna units (RAUs) connecting to the same central unit (CU) control. The FSW scheme provides mobility robustness signalling process that guarantees a successful frequency switching instead of HO, and reduces the probability of radio link failure (RLF) compared to HO process in traditional HSR systems, where the HO failure (HOF) rate is about 21%. The analytical results show that the proposed scheme outperforms traditional HO schemes.

Seamless Mobility Under a Dedicated Distributed Antenna System for High-Speed Rail Networks

“…DAS network architecture specially designed for HSR broadband wireless communication system consists of hundreds of remote antenna units (RAUs) deployed linearly along the rail track in a one dimensional fashion, as the new HSR network tends to have less inclination angle nowadays [83]. Each RAU is a simplified radio unit used for transmission/reception.…”

“…Furthermore, the CU can control RAUs up to 20 km, and no HO is needed between RAUs controlled by the same CU, by employing the frequency switch (FSW) scheme [83].…”

Pilot Allocation and Sum-Rate Analysis in Cell-Free Massive MIMO Systems

“…Distributed massive multi-input multi-output (DM-MIMO) is an attractive technology to meet the vast growth in the requirements for huge data rates in future wireless communication systems [1], [2]. A distributed antenna system (DAS) with spatially separated antennas provides a better coverage, power saving and capacity merits than a co-located antenna system (CAS) at the cost of high fronthaul requirements [3]. Since DM-MIMO combines both DAS and massive MIMO concepts, it will bring all the benefits from these two systems [4].…”

An Expedited Predictive Distributed Antenna System Based Handover Scheme for High-Speed Railway

“…9. Which was used in [8] to equalize the effect of the train varying speed, so that varying speed will have the same HO triggering probability which can be obtained as.…”

“…RAUs are connected to the CU via either a fiber link or a wireless link. Further, the CU can control RAUs up to 20 km, and no HO is needed between RAUs controlled by the same CU, by employing frequency switch (FSW) scheme [8], where a frequency pattern moves/switches among RAUs along with the movement of a train so that the train is always served by the same frequency. Therefore, DAS is considered as the most effective solution to deal with the frequent HO issue in HSR mobile broadband wireless communications.…”