Satellite connectivity while driving traditionally has been possible by using handheld, pay-by-the-minute satellite phones. More recently, always-on services have come to the forefront by using satellite tracking antennas installed on vehicles. Vehicle-Mounted Earth Stations (VMES) currently can operate on conventional Ku-band frequencies but only on a secondary basis. This means VMES cannot claim interference protection from primary services such as fixed systems and Earth Stations on Vessels (ESV). A pending notice of proposed rulemaking by the U.S. Federal Communications Commission proposes to offer co-primary status to VMES.

Applications of VMES

As opposed to vehicle-mounted, push-button auto-deployable antennas, which can operate while the vehicle is parked, VMES use antennas that operate while the vehicle is in motion. VMES have long been vital for vehicles involved in military operations, however, demand for commercial applications has encouraged regulators to propose a co-primary allocation status in Ku-band for VMES. 
Applications standing to benefit from a co-primary allocation of VMES include satellite newsgathering, weather services, oil and gas exploration and extraction, and large construction projects. Primary protection for on-the-move, high-speed Internet; Voice Over Internet Protocol; streaming video and virtual private networks are a few benefits that these applications could get. VMES are suited especially for disaster recovery applications, because VMES are independent from local power infrastructures (e.g. they draw their power directly from the vehicle).  In addition, VMES completely bypass local terrestrial networks.
 

Land Mobile Allocation

Today, if a service provider wants to offer Ku-band satellite services on mobile vehicles it first has to secure an authorization in the Land Mobile Satellite Service (LMSS) allocation. However, LMSS licensees operate on a secondary allocation basis on the uplink and a non-conforming basis on the downlink. This means that LMSS users cannot claim interference protection from fixed services and ESVs which operate on a primary basis.

The Challenges of Regulating VMES

Regulation of VMES in the co-primary status is not without challenges. There are three primary concerns of allowing VMES to share a co-primary status in Ku-band: 

• Ability to Maintain Pointing Accuracy: Vehicles can abruptly accelerate and decelerate as well as travel in rough terrain. Under these conditions, VMES may find it difficult or impossible (or perhaps prohibitively expensive) to maintain their pointing accuracy. Of greater practicality may be the ability of antenna systems to automatically mute transmissions upon deviation from the target satellite.
• Danger of Using Ultra Small Antennas: Vehicles cannot accommodate the larger antennas that can be installed on ships. Thus, ultra-small stabilized antennas are more practical for VMES.  However, smaller antennas have greater potential for interference to adjacent satellites because they have wider side lobes that consequentially radiate more energy to satellites on either side of the intended satellite. 
• Ability to Track Potential Interference: Because of the ubiquity of vehicles and their unpredictable driving patterns, a method to identify and correct interference issues is paramount. The ability to use antenna or vehicle GPS to log geographical coordinates probably provides a solution. 

Although not an issue of primary or secondary allocation, another concern has to do with human exposure to radio frequency (RF) radiation, because in most instances, VMES require a driver to sit underneath the antenna. 
In summary, a co-primary allocation of VMES in the conventional Ku-band would be in the public interest, as it would address a growing commercial demand for on-the-move services. However, a co-primary allocation would also have to be conditioned on strict adherence to interference avoidance mechanisms.