Nervous Breakdown

Cellular backhaul on the verge

You know the feeling. The to-do list is growing, errands need to be done, bills need to be paid, and perhaps you have a job and a family and a fantasy football league to attend to, all at once. But before you head out to the time-management clinic, consider this: You have nothing on cellular backhaul, which soon will reach its breaking point as the demands placed upon it outstrip its existing abilities.

All those text messages flying around the mobile network, plus adoption of more data and video services, have made for more and more traffic at the cell sites that needs to be backhauled to the switching center. The ongoing rollout of 3G will accelerate user adoption of bandwidth-hungry broadband services, and, to boot, the number of subscribers is skyrocketing too, forecast to reach 3 billion people worldwide by 2009, according to Infonetics Research.

All of that’s a lot for a couple of T1 lines to handle, and the cellular companies are having to take a look at ways to head off a capacity breakdown. About 90 percent of cell sites in the United States are connected to switching centers and transport networks by copper T1 lines, leased from the LECs for $400 to $700 per month. As bandwidth needs grow, carriers simply could add more T1 lines. However, the economics of that rapidly become prohibitive if the ARPUs do not increase enough to justify the costs to support the traffic.

“Operator revenues are not increasing in line with the bandwidth, as they did with voice traffic growth,” explains Hamid Lalani, senior vice president of marketing and product management at Aktino Inc., an Ethernet over copper vendor. “Data services account for only 20 percent of the revenue but take up more bandwidth than all the voice traffic combined, resulting in a much higher cost-per-bit.”

Backhaul also is the most expensive portion of network opex. Mobile operators spent $16 billion on mobile backhaul links worldwide last year, and will spend double that in 2009, says Infonetics. In fact, about 30 percent of operator revenue goes to technical operations, two-thirds of which is comprised of backhaul costs. That translates into a cash cow for the RBOCs, but a major drain for those wireless operators not affiliated with a LEC.

Further, existing backhaul strategies have made reliability an issue. “Because the industry is maturing, they are not just competing on price — carriers have spent billions in advertising to create the perception of reliability, but copper backhaul remains a weak link,” says Lalani. “It’s the No. 1 source of failure at the cell site, because it’s susceptible to lightning, extreme temperatures and other factors. It hasn’t been upgraded in 20 years.”

Something’s Gotta Give
In light of the demands being placed on a soon-to-be-maxed-out backhaul network, cellular operators are moving to apply stress reduction therapies to avert the crisis, helped along by the backhaul alternatives multiplying in the marketplace.

Aktino, for instance, offers copper bonding, which quadruples the bandwidth available on a per-pair basis. Two T1 circuits now effectively become eight. “So you can give 400 percent more capacity on the same physical plant just by installing new electronics,” says Lalani. “And now, with multiple pairs together on the physical layer, you can provide redundancy and re-route capabilities in the case of an outage.”

Click to Enlarge Nextlink’s broadband wireless solution, including wireless backhaul from cell sites

Another approach is aggregation, which will become particularly handy as cell site traffic migrates to IP. Operators can multiplex lower-speed data feeds at the base station into a single, fatter pipe (DS3, IP, ATM or metro Ethernet services), by way of a multiservice provisioning platform available from vendors like Cisco Systems Inc. and Kentrox LLC. Operators then pay for the single higher-speed line to the switching center, lowering their cost-per-bit for backhaul. These platforms also offer radio-access network optimization, and built-in redundancy and service protection.

So-called “wireless fiber” technology is another emerging alternative for cellular operators from companies like FiberTower Corp., GigaBeam Corp., Harris MCD and Nextlink Wireless Inc. “Very few base stations are covered by fiber today, and it is more expensive than adding T1s to trench it to the cell site,” says Tim Dunne, vice president of business operations at Nextlink, which offers wireless metro Ethernet services it says can offer 20 percent to 50 percent backhaul savings over leasing T1s. “We can cover, in general, 40 to 70 percent of a given market’s cell sites with five-nines reliability, depending on line-of-site and topographical characteristics and where we can put in hubs.” Nextlink offers a turnkey service for carriers where it provides equipment, maintenance, engineering, installation and operations, and the links can run both TDM and Ethernet IP traffic.

Whichever direction carriers choose to go, the next three years promise a significant evolution in the backhaul arena. “The LECs don’t want to let go of those checks,” says Lalani. “But their strategy going forward will have to deal with this transition to a more efficient physical layer.”

Share this article: Email, Slashdot, Digg, Del.icio.us, Yahoo!MyWeb, Windows Live Favorites, Furl
Add this article feed to: RSS, My Yahoo, Newsgator, Bloglines