With every announcement of a multimedia-friendly mobile device like the iPhone, the broadband pipes of wireless networks fill with more promise that 2007 could be the year mobile broadband content and applications push the limits of traditional network backhaul methods.

Fiber, copper and fixed wireless have been used for backhaul to this point, or are poised to take on a greater role, enabled with the capabilities of IP-based Ethernet or other technologies. An infrastructure option that gets far less attention is satellite, but that may change with recent moves by equipment vendors to position satellite as a viable backhaul technology.

NMS Communications, whose AccessGate radio access network optimization solution already is used to help provide backhaul transport over other infrastructures, last month was certified for interoperability with broadband satellite modems from Hughes Network Systems. That announcement came as many international GSM network operators are turning to satellite for backhaul capacity and also not long after a report by Frost & Sullivan that suggested there could be up to 18,000 cell sites worldwide that use satellite-based backhaul technology this year.

Namibia-based MTC is perhaps a prototype satellite backhaul user, working with Advanced Telecoms and VSAT service provider SatCom to backhaul 15 of its cell sites late last year. Elsewhere, satellite carrier ViaSat and partner Verso developed a backhaul solution for PNG Telekom of Papua New Guinea that will be used this year to link 50 cell sites in that carrier's home market.

“There are many parts of the world where terrestrial lines can't reach, and VSAT networks are at the point now where they are well-established,“ said Rich Kane, product director for NMS’ AccessGate line. “Hughes uses IP-based technology over satellite, so this is just another situation of using an IP technology for backhaul.“

NMS has announced similar interoperability certifications with VSAT equipment-makers like iDirect and others since announcing a version of the AccessGate platform targeted at satellite-based backhaul in early 2006.

The upcoming Satellite 2007 trade show in Washington, D.C., Feb. 19-22, likely will showcase further satellite-fed backhaul solutions, including a session dedicated to GSM backhaul opportunities for satellite networks.

While satellite emerges as a backhaul option for remote or greenfield networks, other backhaul equipment vendors continue to improve their solutions. Backhaul for mobile broadband will be a hot topic at the 3GSM World Congress in Barcelona, Spain, Feb. 12-17. RAD Data Communications provided a preview of its plans for the show last week, saying it is launching a complete suite of backhaul solutions, including the ACE-3600 multi-service aggregation unit, which allows pseudowire transport of ATM traffic over a packet network. The suite also includes gateway products for cell sites, voice trunking and bandwidth optimization.

ATM interfaces are common on mobile infrastructure equipment, and many base stations and cell sites are expected to have IP interfaces in the years to come, with pseudowire playing an important role in between, as backhaul providers like ILECs look to use their carrier Ethernet services to carry backhaul traffic.

Pseudowire boxes also are coming down in price, which might encourage wireless carriers to consider owning their own pseudowire equipment at the cell site to transfer backhaul traffic onto leased pipes. Eitan Schwartz, vice president and general manager of the TDMoIP division at RAD Data Communications USA, said that isn't likely to be the rule. “It might make sense for some of the wireless carriers, but not for others, to buy their own pseudowire equipment,” he said. “You could have your own gear and just buy the carrier Ethernet pipes, but some of them won't want the hassle of installing equipment in their networks that they aren't familiar with.”