A radio frequency band within the Lower 700 MHz band, near 720 MHz.
Unlike most bands used for phone service, band 29 is an unpaired band. A paired band has two sections, one for communication in each direction (tower-to-phone and phone-to-tower).
Band 29 is currently owned by AT&T and used for LTE service. Since it is unpaired spectrum, AT&T has deployed it in a downlink-only configuration. That means it only provides one-way (tower-to-phone) communication, providing faster download speeds when used in conjunction with other bands, such as band 12/17. This use of multiple bands simultaneously is known as Carrier Aggregation.
See: Carrier Aggregation