T-Mobile US (TMUS) announced that its wholly owned subsidiary has signed an agreement to purchase 10 MHz of Advanced Wireless Services spectrum from U.S. Cellular (USM) for $308M in cash. The spectrum covers a total of 32M people in 29 markets in the Mississippi Valley region — notably in St. Louis; Nashville; Kansas City; Memphis; Lexington; Little Rock-North Little Rock; Birmingham; New Orleans; and Louisville. This additional spectrum will allow for an incremental roll-out of T-Mobile’s 4G LTE network coverage to new markets and expands the existing 4G LTE bandwidth in the Mississippi Valley region, T-Mobile said. The agreement is subject to approval by the Federal Communications Commission and Department of Justice, and other customary closing conditions. Following regulatory approval, the transaction is expected to close in the fourth quarter of 2013.