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Ready to abandon your landline, but stymied by poor indoor cell reception? Two new technologies--one that lets you make calls over your home Wi-Fi network through your cell phone and another that uses tiny, in-home cell towers called "femtocells"--are emerging to fill gaps in cell coverage.

Both services make use of your broadband connection to route in-home cell phone calls over the Internet using VoIP, but they let you make and receive calls directly from your mobile handset, with your regular cell number. You can start a call indoors over broadband and continue it outside over cellular, and vice versa. According to early adopters, both systems are transparent to use and both function well.

Your Own Cell Tower

Sprint's Airave system places a miniature cell tower, called a femtocell, in your house. The service is being tested in Denver, Indianapolis, and Nashville, and is set to roll out to the rest of the country in 2008. The Airave hooks up directly to your broadband router. When in range of the Airave, any Sprint handset will connect automatically to the device, which will then transmit calls over the Internet. As many as three handsets, from a pool of up to 50 "registered" phones, can make or receive calls simultaneously on a single femtocell. Additional callers are routed to the nearest cell tower.

We couldn't test the Airave, but early users report that handoffs between tower and femtocell work well and that call quality is excellent. Sprint charges $15 per month per line for unlimited calling ($30 for a family plan), in addition to $50 for the Airave hardware.

The Home Hotspot

T-Mobile's HotSpot@Home (which we've reviewed alongside the new BlackBerry Curve 8320) went nationwide this summer. It uses hybrid handsets that switch from a cellular network to Wi-Fi when you move into range of a hotspot. But built-in Wi-Fi isn't enough, as special circuitry must perform the handoffs between the Wi-Fi and cellular networks. Only a few handsets work with the service: Nokia's 6086, Samsung's t409, and RIM's 8320. And though any Wi-Fi router will work with the service, T-Mobile sells optimized models from D-Link and Linksys that promise to provide better voice quality and to extend your handset's battery life. (Wi-Fi is a big power eater.)

We tried the service with the Linksys router and the Nokia handset, and it worked right off the bat, with no setup beyond creating a Wi-Fi encryption password. The phone automatically connects when you move within range of the router, and you simply make and receive calls as you normally would. It also works at any hotspot that doesn't require a browser log-in screen, and the service kicks in free of charge at any T-Mobile hotspot. In our tests, voice quality was similar to that of calls made using VoIP service Vonage.

T-Mobile's fees are in the same ballpark as Sprint's: An optional special router costs $50, and unlimited Wi-Fi calling is $20 per month per line or $30 for a family plan. You can also let Wi-Fi calls use your cell minutes and pay no extra monthly charge.

Signal Boosters

If you'd rather not pay a monthly fee for expanded cell coverage, a cellular signal booster such as those from Wi-Ex and Wilson Electronics might be a better alternative. For $400 you can buy a dual-band amplifier and antenna system that works with both CDMA providers (such as Sprint and Verizon) and GSM carriers (AT&T and T-Mobile). Cell boosters require an antenna in a spot (often outdoors) that has good reception--the amplifier can boost indoor signal strength only to the level the outdoor antenna receives. But they work with any normal handset, and can even boost 3G data access.

All three technologies can liberate you from your landline and save money. The best fit for you will depend on your carrier, coverage, and calling patterns. Expect to see more offerings in 2008, with new equipment--such as integrated femtocell/Wi-Fi routers--coming from Netgear and other networking vendors. Also expect a variety of pricing strategies, such as a monthly fee for unlimited calls within a "home zone" around your home or office, or equipment leases. While the options may be more complex, the end result should simplify your life.