Backhaul may not be the sexiest part of a 4G migration, but legacy backhaul networks cannot support the onslaught of data traffic generated by next-generation mobile services.
The upfront planning is critical. We've made some mistakes in the past that cost us dearly.
Chief Strategy Officer, Digital Bridge Communications
Meticulous planning for mobile backhaul is arguably one of the most important -- and at times underestimated -- ways that wireless carriers' can keep services up and costs down as they map out their Long-Term Evolution (LTE) or WiMax migration strategies.
"Backhaul really makes or breaks business plans in many markets," said Kelley Dunne, founder and chief strategy officer of Digital Bridge Communications, a private mobile broadband provider based in Ashburn, Va. "There are markets in Idaho that we simply could not deploy to because they did not have cost-effective backhaul. It is that big [of] a deal when you're doing an upfront business model and network planning."
Where fiber or copper is already deployed for fixed line services, backhaul is often no more complicated than securing a lease with a tower company and engineering the radios. But expanding a 4G footprint by trenching new fiber or using microwave backhaul raises a slew of concerns beyond just the expense and time to deploy the physical plant -- spectrum licensing, local zoning and right of way issues to name a few.
Dunne made his comments as part of a panel discussion on 4G backhaul network strategy this week at 4G World in Chicago. MetroPCS, the first North American carrier to launch a commercial LTE network, and LightSquared, a startup whose wholesale LTE network goes live in late 2011, also shared their strategies with the panel.
"It's as much about total cost of ownership modeling in the design process as it is the actual traditional engineering and design," said Mike Dodson, vice president of core, transport and backhaul planning for LightSquared's greenfield terrestrial and satellite LTE network. "You really need tools and ways to figure out what really is the best choice when presented with a number of options."
Enhancements to high-speed radio access networks (RAN) and advanced subscriber services often overshadow the attention awarded to the aggregation layer requirements for 4G networks. But without the right backhaul network plan to distribute traffic and alleviate congestion, power users with access to 50 to 100 Mbps speeds are going clog up the network rapidly.
"We're seeing incredible demands on 4G networks to the tune of 5 gigs to 7 gigs a month on the average users," Dunne said. "I think that's really driven the need to have robust, flexible, expandable and scalable backhaul networks."
Time to market, cost and complexity were major considerations when MetroPCS was developing its backhaul network strategy, according to Ken Geisheimer, distinguished member of technical staff in the CTO's office at the Richardson, Texas,-based low-cost carrier.
"[Backhaul] is probably the largest cost for an operator other than building 10,000 cell sites," Geisheimer said in an interview after the panel. "I think people underestimate that."
Dangers of rushing 4G backhaul network planning
Under competitive pressures to be the first to market, carriers have traditionally failed to evaluate and compare all technology options or calculate the total cost of ownership, according to Marty Snyder, president of Communications Infrastructure Corp (CIC), a wireless infrastructure and engineering firm based in Santa Barbara, Calif. Missteps and poor insight usually forced them to start over, delaying deployments more than if they had done more thorough planning, he said.
"We believe there's a critical shift already taking place in the way wireless backhaul networks are planned," he said. "It's a shift in how the network engineering processes are tied to the financial planning to [improve] the true quality and profitability of the network."
In the rush to launch some of its earliest commercial LTE deployments in 2007, Digital Bridge suffered congestion and service delivery problems partly due to an incomplete wireless backhaul network, Dunne said in an interview after the panel.
The experience taught him not to scrimp on backhaul network planning when launching wireless services in a new market. All cell sites and backhaul networks in a new market must be ready to light up simultaneously to avoid any surprises, he said.
"The upfront planning is critical. We've made some mistakes in the past that cost us dearly," Dunne said. "You've got to turn on your sites all at once … and not have any service holes … prior to launch."
Finding the right backhaul network strategy
There is no universally prescribed process that will work for every 4G backhaul plan. With little in-house microwave engineering experience, MetroPCS decided to outsource it microwave backhaul network designing and planning rather than retrain its engineers, Geisheimer said.
LightSquared's microwave, fiber and radio frequency (RF) engineers collaborate when building out a new service area so that the result is a network plan that covers all aspects, Dodson said. They are supported by professional services from the carrier's main LTE vendor, Nokia Siemens Networks.
"The backhaul design is very much a part of the RF design," he said. "We take the RF engineers, the microwave engineers that really know how to do microwave, the fiber engineers that really know about all the access vendors and other providers. It's really a [collaborative] effort."
Digital Bridge has dedicated part of its backhaul planning to find ways to generate more revenue from its investment in an almost all-microwave backhaul. The carrier is exploring whether it can offer part of its backhaul network capacity for private point-to-point or point-to-multipoint transport for local organizations with campus networks, such as hospitals and universities, he said.
"When you build and invest in a mesh microwave backhaul, it's expensive," Dunne said. "One of the things we started to think about is: The microwave network as an asset… [We are looking] at how to leverage that investment."
Let us know what you think about the story; email: Jessica Scarpati, News Writer