BLU phones includes whole America compatibility on all GSM Networks including AT&T, T-Mobile, Cricket, MetroPCS, Straight Talk, and others networks.
For your phone to support, your carrier should support the following frequncies: 4G LTE, (1/2/3/4/7/12/17/28), and 3G HSPA+ (850/900/1700/1900/2100).
By the way, which handset do you have?