Node B

As in all cellular systems, such as UMTS and GSM, the Node B contains radio frequency transmitter(s) and the receiver(s) used to communicate directly with mobile devices, which move freely around it.

However, this is changing with the emergence of High Speed Downlink Packet Access (HSDPA), where some logic (e.g., retransmission) is handled on the Node B for lower response times.

This requires a larger number of Node Bs and careful planning in 3G (UMTS) networks.

An equipment cabinet contains e.g. RF power amplifiers, digital signal processors and backup batteries.

However, the tendency nowadays is to camouflage the antenna (paint it the color of the building or put it into an RF-transparent enclosure).