Exalt/ XO partnership to leverage unique LMDS characteristics for mobile backhaul

Wireless equipment manufacturer Exalt Communications is developing equipment for use in LMDS spectrum bands that could have certain advantages for wireless backhaul deployments, the company said. Exalt is developing the equipment, expected to be available in third quarter, for use in spectrum bands licensed to XO Communications. XO holds LMDS licenses in 81 U.S. metro markets, which it currently uses to provide mobile backhaul and high-speed access based on equipment from several different suppliers.

Microcells and picocells are a key target
One of the advantages of using LMDS for mobile backhaul relates to its flexible band plan, said Eric Miller, senior wireless strategist for XO, in an interview with Connected Planet. “Because there is no rigid band plan for LMDS, we can aggregate,” said Miller. “We can take a wider channel and use it to deliver a full gigabit over a single RF carrier to create a cheaper more efficient radio.”

Another unique opportunity will be to serve microcells and picocells—two options that got a lot of attention at the recent CTIA show.

Network operators envision deploying microcells and picocells in urban core networks to enhance coverage and capacity, but it will be challenging to bring high-speed landline connectivity to these sites, which may be located, for example, on lamp posts. However, a wireless approach that uses Exalt equipment and XO spectrum could be an excellent solution, Miller said.

One of the factors that makes LMDS well suited for picocell and microcell use is that the antennas used with it can be very small and unobtrusive, explained Exalt Communications CEO Amir Zoufonoun.

Miller also sees the Exalt/XO approach being used as network operators expand their new LTE networks from major metro core areas to outlying suburban and rural areas. In a typical scenario, a network operator would use the Exalt/XO solution to aggregate traffic from three to five additional towers anchored by an existing tower that has fiber connectivity.

LMDS Renaissance?
The range that LMDS can support varies depending on a variety of factors, but the “sweet spot” is about two to three miles, Miller said.

XO has had LMDS spectrum since the 1990s. A few years ago it operated the LMDS business as a separate company known as Nextlink but since then made the decision to bring the operations back into the parent company to save on administrative and other costs, Miller said.

LMDS was originally used in the 1990s to support point-to-multipoint connectivity at T-1 or T-3 speeds. As Zoufonoun explained, “Today there has been a complete shift to 100 Mb/s per building so the idea of multipoint doesn’t work.”

Fortunately, however, LMDS technology has advanced to where radios that would have cost $250,000 in the 1990s are now in the $5,000 to $10,000 range, making point-to-point systems a viable option, said Zoufonoun.

Carl True, director of strategic development for XO Carrier Services, added that LMDS-based wireless connectivity should be more economical than copper-based solutions for speeds of 50 Mb/s or higher.