Time Warner Cable said Monday it has made its Wi-Fi hotspots in Charlotte, North Carolina, free to use while the convention is in town. AT&T, Verizon Wireless and Sprint Nextel all have added cell sites, portable COWs (cells on wheels) and distributed antennas to handle the influx. More than 35,000 people are expected to come to the city for this week's convention, which began on Monday.

Though steps to boost mobile data capacity for the quadrennial presidential conventions have been accelerated and in some cases are temporary, they are likely to be an early signal of what service providers will have to do to keep up with rapidly growing mobile use around the country. The Federal Communications Commission forecast in 2009 that U.S. mobile data traffic would grow by 35 times in five years. While the FCC and mobile industry are working on ways of devoting more spectrum to mobile, part of addressing expected shortfalls in capacity will be making of frequencies and simple deployment of more infrastructure.

For service providers, the political conventions are not just two more large events that need service. and of wireless spectrum are in which carriers, cable operators and online companies all have interests. Google is also putting on its best face for the political decision-makers, setting up large gathering spaces at both conventions with cafés, fast Wi-Fi and video studios.

Time Warner has 90 Wi-Fi APs (access points) around the Charlotte area that were set up to provide wireless Internet access to its subscribers while away from home. Residents and visitors can also buy service. TWC also has about 120 APs throughout Time Warner Cable Arena, the main venue for the event. The company will make those hotspots available to convention-goers free from Aug. 27 through Sept. 10. The visitors, and anyone else in the area, will be able to get on the system without a username or password.

Wi-Fi is a critical tool for cable operators such as Time Warner to offer a mobile component to their Internet service, and also plays a role in carriers' urban capacity plans because it uses shared spectrum. But filling in densely populated spaces such as arenas poses special challenges, according to Ruckus Wireless, which supplied the access points to be used in the convention venue.