Wireless companies beefing up systems to try to ensure there won't be dead spots at convention

Verizon Wireless isn't quite ready to guarantee perfect cellphone coverage for the 35,000 delegates, journalists, and political animals who will be in Boston this month for the Democratic National Convention.

But it's spending nearly $2 million to try.

Verizon -- the largest US wireless carrier as well as the one that most heavily promotes its reputation for having the best coverage -- has rolled out a battery of cell-site upgrades in and around the FleetCenter. That will add about 20 percent more calling capacity.

A new transmitter on the arena ceiling can handle up to 400 simultaneous calls.

And along with most other wireless carriers, Verizon is planning to roll in a COW -- the industry's nickname for a cell on wheels, or a tractor-trailer unit that creates a temporary wireless relay site.

For wireless companies, the biggest challenge is getting enough calling channels in service around the FleetCenter, to reduce or eliminate the threat of conventioneers experiencing a busy signal. Eliminating ''dead spots" is less of a concern, because existing coverage in the area is generally good.

''No one can promise perfection," said Verizon spokeswoman J. Abra Degbor, ''but it is our expectation that during the convention customers will continue to experience the same level of high quality service as today, despite the increased number of people in the area.

''We're planning to make sure our network continues to perform better than our competitors'."

Richard Enright, Verizon's director of network engineering for New England, said most of the increased capacity will remain in place after the July 26-29 convention ends, in part because Verizon finds that demand for service rises in August as college students return to town.

Although most carriers plan to bring in COW units, Enright and executives of other companies said beefing up coverage for the convention will be significantly easier than for an event like a concert or a championship sports game at a stadium.

Verizon, Cingular Wireless, AT&T Wireless Services Inc., and Nextel Communications Inc. already have invested heavily in providing coverage to North Station railroad commuters, Boston Bruins and Celtics fans, and Bulfinch Triangle office workers. As they clear out and Democrats and news reporters pour in, existing networks should be able to handle most of convention-goers' needs.

''To support this type of event from a wireless telecommunications standpoint is easier than having to make available infrastructure in a remote area, like a Phish concert in Vermont," Enright said.

Cingular spokeswoman Alexa G. Kaufman said her company is using mainly software upgrades, rather than new equipment, to create two to four times as many permanent calling channels in several zones around the FleetCenter.

AT&T Wireless spokesman Marty Nee said AT&T has ''doubled the capacity of our cell sites pointing toward the Fleet Center area" and upgraded coverage around downtown by 30 percent.

During the convention week, Nee added, AT&T Wireless is assigning senior managers to work round-the-clock shifts monitoring the local network and responding to any problems.

Nextel, meanwhile, has landed deals to be the ''official" wireless sponsor of both the Democratic convention and the Aug. 30-Sept. 2 Republican convention in New York City.

Nextel is providing its walkie-talkie style DirectConnect handsets, BlackBerry wireless e-mail devices, and wireless data cards for laptop computers. It has not said how much it is contributing to the party organizations.

''Convention organizers and participants will communicate safely and reliably during the convention," said Bob Johnson, senior vice president for Nextel, ''and the significant enhancements to our network will improve Nextel's service in Greater Boston for years to come."