Supporting continuous broadband satellite connectivity to mobile devices is challenging. While mobile satellite services at lower satellite frequencies (L-band in particular) have been available for some time, these services tend to provide lower rates of speed (up to 400 kbps) and also tend to be very expensive. Satellite broadband using higher frequency services such as Ku-band can provide more bandwidth at a lower cost. But the very nature of these higher frequency services presents a significant challenge for the mobile terminal.
Some of the challenges are outlined below.
Changing Transmission Path
- As mobile broadband terminals travel, they will move through various contours of the satellite footprint and this causes the path to the satellite to change. The challenge is for the satellite broadband system to dynamically adapt to changing link conditions in order to maintain availability while not wasting satellite capacity.
Frequent Blockage
- As mobile vehicles travel, they will pass under various obstacles such as trees, overpasses and tunnels which will obstruct the channel path to the satellite. The challenge is to be able to recover the link as quickly as possible.
Antenna
- Particularly for trains, the antenna must be of a very low profile as the clearance between the top of train car and tunnels and overpasses is often as little as 50 cm. The antenna must conform to these height restrictions while providing the performance demanded to close the link.
Harsh Locations
- By their very nature, mobile vehicles provide a harsh environment for any type of electronics. This includes continuous vibrations, dust, and temperature extremes. For electronics to work well in this challenging environment, they must be of a robust design.
Hughes has enhanced and optimized our satellite broadband products and services to directly address the key requirements found in many mobile applications. These features have been fully incorporated and integrated into the HX satellite broadband systems. Some of the key features include:
- DVB-S2/ACM
- Adaptive Inroute Selection
- TDMA Channel Spreading
- Outbound Flywheel
- Doppler Compensation
- IP Steady State
- Ruggedized Chassis
For more detailed information on the Hughes enhancements to support mobile broadband using the HX System click here.
Hughes has successfully deployed mobile broadband VSAT systems in a number of locations including for trains. Click here for further information.
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