B28 (700 MHz)

The 3GPP LTE Band 28, referred to as APT 700, operates within the 700 MHz spectrum following the Asia-Pacific Telecommunity (APT) band plan. This frequency range was made available for mobile services after the transition from analogue to digital television, commonly referred to as the "digital dividend". Benefitting from its sub-1 GHz positioning, Band 28 offers excellent propagation characteristics and wide channel widths, ensuring wide area coverage and strong indoor penetration. Its technical advantages, coupled with the harmonised band plan, have contributed to its widespread adoption across various regions, making it one of the most universally utilised bands for LTE deployments.

B28 band is an LTE frequency division duplexing (FDDFDD: A communication technology that uses separate frequency bands for transmitting and receiving operations. This technique enables simultaneous bi-directional communication by allocating one frequency band for upstream (transmission from the user equipment to the base station) and another distinct…) band split into 703 to 748 MHz / 758 to 803 MHz. In some applications the B28 band is implemented as B28A (703 to 733 MHz / 758 to 788 MHz) and B28B (718 to 748 MHz / 773-803 MHz). Each of the B28A and B28B bands is typically provided with its own duplexer due to, for example, challenges associated with bandwidth and duplex gap.

700 MHz LTE has been a popular choice due to availability of digital-dividend spectrum, and unmatched propagation characteristics permitting wide area coverage in regional and rural environments, and excellent in-building coverage. Due to its large wavelength, B28 does not easily support Massive MIMOMassive MIMO: A wireless communication architecture that uses a large number of antennas (often denoted as 'massive' due to the scale, typically in the order of tens or even hundreds) at the transmitter and receiver to facilitate multiple simultaneous data streams. Massive MIMO uses techniques like beamforming,… and beamforming technologies.

Notably, B28 cannot be deployed as a standalone 1.4 MHz LTE-MLTE-M: LTE-M is a type of LTE network published by 3GPP in Releases 13 to 15 specifications. LTE-M is a low power wide area technology which supports IoT through lower device complexity and provides extended coverage, leveraging a mobile operator's existing LTE base stations. LTE-M finds its… network, instead LTE-M must be deployed in-band.