Finally, there is another solution that T-Mobile USA has adopted, which the company is marketing as “Hotspot@Home.” Consumers may purchase wireless routers and enhance their in-home coverage utilizing a technology called Unlicensed Mobile Access, which also has traction among overseas carriers as well.

The challenges
The drawback of UMA: It requires mobile phones equipped with Wi-Fi (although more Wi-Fi equipped handsets and devices are becoming available to consumers).

In his article, Continuous Computing’s Singh pointed out several challenges to the widespread usage of femtocells:

• Integrating millions of femtocells with an existing 3G wireless core infrastructure.
• Managing RF interference
• Security. “Since the traffic from femtocells can be carried over a public IP network, the traffic needs to be encrypted to avoid eavesdropping,” he wrote.
• Ensuring quality of service.
• Too much of a good thing. If many tenants in an office or apartment building use femtocells, it could lead to interference. (The same could be said for picocells.)

As for DAS: One of the biggest challenges is getting the system in place. Femtocells and picocells aren’t very obtrusive, and their remote antennas can be moved with ease. DAS has more infrastructure worries, and the cost can be high. Also, the industry has not yet established uniform standards, so there are competing technologies at play. And remember that carriers are responsible to the FCC to ensure that the higher output generated by a DAS does not interfere with other wireless services, so they must pre-approve any privately installed systems.

Wireless carriers often will help with the cost, since it’s to their financial advantages, said Dave Kaun of Elert & Associates. But you want the infrastructure to be as unobtrusive as possible. One college put the antennas in the light poles of the football stadium. Casinos, government buildings and other large campuses also employ “hiding” techniques.

Of course, it’s always easier to build in the system when the client is constructing a new building. But clients who do that must be sure the system also supports radio traffic for emergency responders. “Always make that a priority,” Kaun said. And be aware that some cities now require that police and fire fighters’ handheld radios have good coverage in new commercial buildings.