AWS Auctions Set Off Backhaul Reshuffle

The planned August 2006 advanced wireless services (AWS) spectrum auctions in the USA will be accompanied by specific backhaul challenges, according to industry experts at wireless solutions group, Radio Frequency Systems (RFS). While the 'new' 1700 and 2100-MHz spectrum will provide bandwidth for commercial mobile phone carriers hoping to deploy 3G services, the story will be different for incumbents already using these bands for wireless backhaul applications. They must find new backhaul routes - and quickly - to allow them to vacate the spectrum without disrupting existing services.

According to Asad Zoberi, RFS's microwave area product manager, the new licensees - who will foot the bill for backhaul relocation - are likely to want to liberate the spectrum right away.

The spectrum being auctioned by the Federal Communications Commission (FCC) comprises the 1710 to 1755-MHz band (currently utilized by federal government organizations), and the 2110 to 2150-MHz band (allocated to non-government). "In key markets, especially - such as New York or Los Angeles - there could even be a measure of transitional frequency sharing, providing no interference is generated. Whatever the case, speed of deployment will be a key factor in the choice of new backhaul mechanism," said Zoberi.

Several backhaul options exist - lease of existing T1 lines, deployment of fiber networks, utilization of existing microwave backhaul systems in neighboring bands, or relocation of backhaul services to different bands.

"T1 lines present a speedy solution, but incur ongoing leasing costs that dramatically increase overall cost of the system," said Zoberi. Fiber networks, he said, are fast and high-capacity, but are difficult and expensive to deploy- especially over rugged terrain - and are more susceptible to natural disasters. Microwave links, on the other hand, can cover great distances without incurring extra cost, can be deployed quickly, and can offer payback periods of less than two years. Furthermore, with microwave backhaul, users have total control of the system.

Federal government incumbents currently using the 1710 to 1755-MHz band can opt to use existing systems in the 1750 to 1850-MHz band, or deploy new systems in the 4 or 7-GHz bands. Similarly, non-government incumbents (2110 to 2150-MHz) can use existing 2450 to 2483-MHz systems, or move to the 6, 10, 11 or 18-GHz bands. The decision, said Zoberi, lies in the desired application.

"It appear faster and more cost-effective to use existing microwave antenna systems, but these may already be capacity-limited, or comprise old equipment; better, perhaps, to upgrade to digital technology, where capacity is much less of an issue. The 4, 6 and 7-GHz bands are, for the most part, ideal for high-capacity, long-distance microwave links; higher frequency bands are more applicable for links over medium or short-distances," said Zoberi.

RFS designs and delivers complete microwave antenna systems for radio link networks in each of the bands being considered. This includes an extensive suite of antennas- including standard, high and ultra-high performance models, and the popular RFS CompactLine, SlimLine ranges - plus FLEXWELL elliptical waveguide, dehydration systems and accessories.

"RFS is committed to providing cost-effective and high performance backhaul solutions," said Zoberi. "We've pioneered the development of small-diameter dishes for easier zoning, that meet FCC part 101 Category A pattern requirements in the 10 and 11-GHz bands, providing more choice for users of this band. Added to that, we have a premium manufacturing facility here in the USA, enabling fast turnaround and system deployment."

Posted to the site on 7th June 2006