AT&T is finally ready to roll out their high-speed 4G LTE network in five initial markets by the end of this week. The carrier is following in the footsteps of its competitor, Verizon Wireless, which launched its LTE network over 10 months ago and has since expanded to provide coverage to over 160 million Americans. According to Fierce Wireless, AT&T will activate LTE networks in Atlanta, Chicago, Dallas, Houston, and San Antonio on September 18. The nationwide carrier plans to expand to 15 markets by the end of 2011. It was previously reported that AT&T had already launched LTE in Chicago, but the network was only supported by two phones and the city still relied primarily on HSPA+.