Americans' use of cell phones has increased so quickly that wireless networks are becoming overloaded, causing a growing number of customers to complain about calls that are inaudible or are cut off or never connected.
And cell phone service could get worse before it gets better, industry experts said, because even as cell phone companies are rolling out features like digital photography and Internet-based games, they are not spending the money needed to improve basic voice service.
"This is a situation in which the wireless industry is a victim of its own success," said Jim Schlichting, deputy chief of the wireless communications bureau at the Federal Communications Commission.
Many of the industry's service problems are a result of the huge growth of new customers. In 56 percent of the nation's households, someone now subscribes to wireless phone service, more than double the percentage in 1995.
The surge in users is straining the capacity on wireless systems, whether because some companies have too few transmitters or transmitters that are too small, or because the local airwaves have become too crowded and companies are unable to obtain larger swaths of radio frequencies.
The problems in cell phone service are compounded by economics. Customers have been attracted by the plunge in prices for wireless service. The average per-minute cost has dropped to 11 cents this year from 56 cents in 1995. For the phone companies that has meant a decline in average revenue per customer to $61 a month, from $74 in 1995.
And so, just when wireless companies need to invest more money to accommodate all the new users, the companies are harder pressed financially to do so.
The FCC tracks only the few hundred complaints it receives _ it recently reported fewer recently than in past years _ but has acknowledged that its figures are inadequate and that an increase in cell phone users had worsened service problems.
Surveys conducted for the industry showed service complaints were rising.
"If I make 10 calls, at least three have to be redialed because they don't go through," said Orville Mills, who lives in Van Cortlandt Park in the Bronx area of New York and recently switched companies to Sprint from VoiceStream. "The new services are just a distraction from not having the basics down."
The percentage of all wireless subscribers who have called customer-service centers at least once in the past year to complain about service or because they had other problems has climbed to 61 percent, from 53 percent in 2000, according to J.D. Power & Associates, a company that measures customer satisfaction in many industries and sells it to the companies being scrutinized.
The level of such calls is higher than for many other consumer-service providers, including fixed-line telephone companies, cable-television operators and stockbrokers, according to J.D. Power. About 30 percent of the calls to customer-service centers of cell phone companies were complaints related to dropped calls, bad reception or calls not going through, up from 19 percent in 2000. Other reasons for calling included complaints and questions about billing, equipment and services.
The author of the study, Kirk Parsons, said the wireless companies were aware of the problems. He said he expected complaints to grow as the companies added services, contributing to stress on the networks and subscribers' confusion.
One problem is the sheer technical complexity of sending and receiving wireless calls. Unlike fixed-line telephone systems in which every line is physically wired to the network, wireless systems rely on a delicate mesh of thousands of interconnected call relay towers that must keep track of calls and pass the signals from region to region even while users themselves may be traveling from region to region.
The relay stations can easily be flooded with call volume. That vulnerability became clear in the hours after the Sept. 11 attacks in New York and Washington, when the local wireless networks were overloaded and effectively shut down by the surge of attempted calls.
Various new companies are trying to develop forms of transmission that could handle such surges. But so far companies remain reliant on systems that, in some ways, still resemble radio communications networks that were first developed for military use in World War II.
"It's important to remember that cell phones are glorified radios," said Travis Larson, a spokesman for the Cellular Telecommunications and Internet Association, the wireless industry's main trade group. "They're subject to interference from a lot of things, from building walls to sunspots to the weather. There will always be a tradeoff between mobility and call quality."