International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 02 | Feb -2017
www.irjet.net
e-ISSN: 2395 -0056 p-ISSN: 2395-0072
A SURVEY ON HIGH QUALITY BROADBAND INTERNET SERVICES IN HIGH SPEED TRAINS Anbin Soji. E1, Janani.A2, Suji Vinnarasi.A3 1Assistant
Professor, Dept of ECE, Adhi college of Engineering and Technology, TamilNadu, India Programmer, Dept of ECE, Dr.M.G.R Educational and Research University, TamilNadu, India ---------------------------------------------------------------------***--------------------------------------------------------------------2
Abstract - In recent years, there is the rapid
development of High speed railways (HSR) all over the world and is deployed widely everywhere. Transmission rate highly depend on the distance between the Base Station (BS) and the train. Hence the transmission of data and services varies over time and distance with different data rates. Most of the passengers travelling over the high speed trains face the fading channel and handover problems. Hence Improved Distributed Antenna System for HSR has been proposed by replacing the overlap region of two adjacent Logical cells by a complete cell called Fixed Handover cell. Another mechanism introduced to improve the handover performance of Long Term Evolution (LTE) is coordinated multiple point transmission technology. This method obtains the diversity gain by receiving signals from the adjacent BSs and thereby increases the quality of receiving signal. This paper deals with the various methods and solutions that are being implemented in high speed train communication and also the advantage of using the RADIATE method for obtaining improved quality of data services. Key Words: LTE, HSR, RADIATE, High speed train communications, handover.
1. INTRODUCTION The rapid development of the technology and economy has made the abrupt growth of internet connections all over the world. This leads to the sudden changes in wireless communication technology. Initially the internet connections are provided in wired connections. Then based on the need of users wireless technology have been introduced. Initially the connections were provided to the users by the cellular network which is a radio based technology. Base stations (BS) are used to transmit and receive using the assigned spectrum. They also evolved as generations and currently often used is third generation (3G) which supports high speed cellular connections for voice as well as video based telephone systems. Recently, trains have been the major location where people are expecting internet connections. 75% of passengers in the trains are the business travelers and they are highly interested in using WI-Fi access in trains and it has been realized. Several opportunities to provide Š 2017, IRJET
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broadband internet access on trains includes technology such as Wi-Fi, WiMax, satellite technologies and radio-overfiber communication on broad trains are complicated because they face several difficulties like high penetration losses of signals which includes high vibration environment that require mechanical isolation of communication devices; thermally challenging environment where heat is the significant issues in train; electrical environment that is proximity to high voltages like electrical trains, high magnetic fields- in magnetic levitation. Other factors which affects train communication also includes limit visibility to wireless communications in tunnels; frequent handoffs in the cellular network which results in packet loss and packet reordering. Hence to enable high-quality broadband Internet services in high speed trains, many solutions have been proposed which are classified into four: Cellular network, radio-over-fiber (RoF), leaky-coaxial-cable and satellite communication based network access. Even though these are effective, still faces some difficulties and drawbacks.
2. Improved Distributed Antenna System Continuous linear coverage can be provided for the high speed vehicle along the highways using Distributed Antenna System (DAS). Radio over fiber network using DAS was initially proposed for the road vehicle communication. Due to its coverage efficiency when compared with conventional network, it is employed in HSR communication. This scheme improves the handover reliability by transforming the hard handover into macro diversity soft-handover in the traditional cellular network.
Fig 1. Improved Distributed Antenna System Even though there is a smaller overlap, there is no enough time for handover when train quickly moves through that region. Hence this Improved DAS has been introduced to ISO 9001:2008 Certified Journal
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