AT&T announced today that it will be upgrading its existing 3G network to provide significantly faster mobile Internet speeds. The upgrade to High-Speed Packet Access technology will provide 7.2 Mbps speeds, doubling the current 3G network speed and serving as a step toward the deployment of an even higher-speed LTE (4G) network in the future. In addition, AT&T has announced plans to enhance its mobile broadband coverage by nearly doubling…