3GPP Band 4, often recognised as the AWS (Advanced Wireless Services) band, played a pivotal role in the 3G UMTS frequency spectrum, particularly in North America and parts of South America. Operating under the Frequency Division Duplex (FDD) system, this band allows for dual-way communication: it transmits from cell towers to mobile devices on frequencies 2110 to 2155 MHz and receives signals from mobile devices on frequencies 1710 to 1755 MHz.
Band 4 (1700 MHz) gained prominence due to regulatory decisions in the Americas that allocated the 1700 MHz and 2100 MHz frequencies for expanded wireless services in the mid-2000s. Located towards the lower end of the higher frequency range, Band 4 offers a reasonable balance between signal penetration and coverage area. The typical coverage radius is around 2 to 10 kilometres, varying based on topographical and infrastructural factors.