Air-to-Ground RAN

The Airvana ATG system uses EV-DO Rev-A as the air interface for air-to-ground communication and delivers an average throughput of 1 Mbps to 2 Mbps to each aircraft. Inside the aircraft cabin, this broadband connection can be shared using WiFi, enabling passengers to access the Internet at broadband speeds, check email, connect to corporate Intranets and make voice calls using Voice over IP (VoIP) while flying.

Broadband in the skies promises to change the way people fly. Today, business travelers and consumers alike carry WiFi enabled laptops and other personal computing devices on-board. The availability of broadband in the aircraft cabin will allow them to stay connected, productive and entertained. Airlines will be able to charge for this service or provide it as a perk to their best passengers. Broadband in the skies will generate a significant high-margin revenue stream for airlines and a significant differentiator for early adopters.

ATG System Architecture

The Airvana ATG Radio Access Network (RAN) consists of EV-DO skyBTS™ base stations, IP-RNC 8500 Radio Network Controllers and the AirVista Element Management System (EMS). Built upon Airvana’s IP-RAN architecture, the ATG RAN is designed to provide high availability, seamless mobility and scalability to continent-wide ATG networks.

The Airvana skyBTS™ base station is optimized for this application. This base station operates in 800 MHz spectrum that has been specially allocated by the US Federal Communications Commission (FCC) and includes special filters that meet the stringent specifications required for operation in this spectrum. It uses EV-DO Rev-A as the air-interface, delivering peak data rates of 3.1 Mbps and 1.8 Mbps for ground-to-air and air-to-ground communication respectively in just 1.25 MHz of spectrum.

The ATG RAN is connected to a standard CDMA Packet Data Serving Node (PDSN).  The PDSN is connected to the service provider’s core network which provides connectivity to the Internet and to services such as Voice-over-IP (VoIP).

Though satellites can provide broadband connectivity to aircraft, satellite-based systems can not provide capacity, cost or latency comparable to a EV-DO ground-based system. A single skyBTS™ base station provides more data throughput than a satellite transponder. Hundreds of skyBTS™ base stations can be deployed at a fraction of the cost of launching a single satellite. While round trip latency on a satellite based system exceeds 300 ms and makes the satellite-based system unusable for VoIP, round-trip delays for an EV-DO Rev-A ATG system stay less than 100 ms.

Partnership with QUALCOMM

Airvana is partnering with QUALCOMM to build the ATG product. The skyBTS™ base station uses QUALCOMM’s CSM6800™ chipset with special software drivers that enable large cell sizes and correct for Doppler shift. Doppler shift - a distortion in radio signals experienced when the radio receiver is moving at a high speed relative to a radio transmitter – is not pronounced in terrestrial vehicular communications because vehicles are typically moving at speeds lower than 80 mph. However, Doppler shift poses a significant challenge in air-to-ground communications where speeds exceed 600 mph. Large cell sizes enabled by the CSM6800™ allow relatively few skyBTS™ base stations to provide coverage to an entire continent.

In addition to providing the CSM6800 chipset, QUALCOMM will supply a special EV-DO Rev-A modem that will be installed in the aircraft. This modem will also correct for Doppler shift and will be optimized to maximize throughput to the aircraft.

Support for Multiple In-flight Access Technologies

With a broadband connection to the aircraft, a service provider can enable multiple access technologies in the cabin. WiFi is expected to be the most commonly deployed access technology as most airline passengers carry Wi-Fi enabled laptops or PDAs. In addition, the airlines or air-to-ground communication providers can deploy CDMA, GSM or UMTS pico-access points in the plane. These access points will enable passengers to use their cell phones to send and receive SMS and MMS messages.

Mobile Broadband in the Skies

Equipped with wireless laptops and PDAs, mobile professionals will be able to stay connected and productive. Consumers will get their preferred entertainment options just as if they are at home. Passengers will be able to use VoIP to contact relatives and update them on the flight status. Airlines will be able to provide these services to their customers at a reasonable price and create new revenue streams for themselves. Mobile broadband in the skies will change how people fly.