Other Proprietary Solutions
In addition to technologies, such as Wi-Fi or WiMAX, other solutions can be used to provide Internet on board trains, the proprietary solutions such as Fluidmesh, Luceor and Reicom.
Fluidmesh  was founded in 2005 by a team of researchers from the Massachusetts Institute of Technology (MIT) and the Polictecnico of Milan. Their goal was to reliably deliver flber-like performance via unlicensed wireless spectrum, providing connectivity for transmission of video, voice, and data. Fluidmesh aims to bring broadband connectivity to sites and environments that are today too hard or large to connect, such as high speed moving vehicles and trains, large-scale industrial sites, distributed infrastructures and complex urban environment.
Fluidmesh developed a transmission protocol called FLUIDITY™ which is a license-free trackside wireless, operating in the 5 GHz band. They claimed to provide broadband up to 100 Mbps on a train running up to 350 km/h without service disruption. Furthermore, handoffs below 3 ms are announced. The system relies on a 2 x 2 MIMO-based radio technology and dual-polarized trackside and on board antennas. In fact, it consists of a modified Wi-Fi.
In June 2014, Amtrak announced its collaboration with the Fluidmesh Company to install dedicated trackside technology on its HST line connecting Boston to Washington, D.C.
Luceor  is a French Company founded in 2005. Luceor is a specialist in outdoor wireless networks developed for 3 main applications: emergency situations (natural disasters, industrial accident), events (political meetings, cultural or sporting events) and infrastructure (industrial sites, public transportations). The solution is based on the WiMESH technology. WiMESH is a routing and mesh technology based on IEEE 802.11n standard. It allows wireless devices to connect to the next, in a dynamic and instant way with no central hierarchy to form a “mesh” structure. Throughputs at UDP level up to 450 Mbps are announced, and mobility is supported until 350 km/h. Furthermore, coverage from 100 m to 10 km are announced.
RATP performed some tests in June 2014, based on the WiMESH technology. Experiments were in the context of tunneling emergency situations, needing new generations of wireless transmission of video streams and voice in mobility and very high speed, such as Luceor equipment.
Reicom  is an Italian Company established in 1999, that develops products for broadband radio and radar systems for telecommunications, industrial, automotive, railway, naval and defense markets. The Reicom competencies are:
- • Software Defined Radio (SDR);
- • Grid computing and cooperative computing;
- • Audio and video streaming technologies;
- • OFDM broadband radio;
- • Ultra Wide Band (UWB) radio technology;
- • Organic MESH Networks.
For the Railway market, the developed products are oriented to solve the problem of connectivity between the train and the ground and between coaches, and to bring real-time CCTV and Infotainment on board. Reicom developed the HSBRA™ (High Speed Broadband Radio Access) technology, relying on SDR for train to trackside broadband communications, tested over 300 km/h. HSBRA™ deals with the layer 1 and 2 of the OSI model, by implementing filtering, equalization, digital conditioning and management of the radio signal. HSBRA™ is designed to optimize and manage electromagnetic channel phenomena like fading, shadowing and Doppler effect. HSBRA™ is developed to be used in Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) applications, addressing both safety and non safety critical applications. The technology relies on a Wi-Fi like technologies, dealing with IEEE 802.11 a/b/g/n and IEEE 802.11p standards, but also IEEE 802.20, IEEE 802.16 (WiMax) and 3G and LTE mobile networks.
Finally, some works are performed on millimeter-wave communication systems in order to solve the problem of degraded performance at high speed and growing traffic demand. In , the authors propose a Mobile Hotspot Network (MHN) of a millimeter-wave communication system as a mobile wireless backhaul. The solution proposes the physical layer design of the MHN uplink and downlink and the assessment of the performance of the two links.
Summary on Radio-Based Solutions
The section showed the different technologies that can be deployed as a dedicated track-to-wayside infrastructure, in order to provide broadband connectivity on board trains. The first observation is that there is just a few existing solutions. Most of them rely on WiMAX technology. However, as already mentioned, this kind of solutions allow an entire control of the Quality of Service, in terms of range and throughputs especially.
The Fluidmesh solution claims providing broadband connectivity up to 100 Mbps until 350 km/h. This solution is not yet largely deployed. To our knowledge, the first passenger service that aims to use it is the Amtrak trains.
The train-to-infrastructure solutions lead to high costs in terms of OPEX and CAPEX. A compromise has to be found between performance and costs (involved features are throughputs and coverage). This kind of solutions can be firstly used as a “gap-filler” solution.