2G/3G/LTE macro cells
The basic workhorse of the mobile network, macro cells provide the bulk of coverage in mobile networks.
The macro network is made up of base stations known as the BTS (Base Transceiver Station), Node B (WCMDA) and eNode B (LTE). They are controlled via a Base Station Controller (BSC) vis the Abis interface, or by Radio Network Controller (RNC) via the IuB. An interface between RNCs -IuR – exists to allow diverse RNCs to manage different NodeBs.
In LTE, RNC functionality is distributed betwee the eNodeB and the MME, with the eNode be directly connected to the the MME (Mobility Management Entity) on the S1 interface. eNodeB’s are connected on the X2 interface.
The BTS is formed of RF, baseband, control and transport modules. The RF module receives signals from mobile devices and converts them to digital data. The baseband module processes the encoded signal from the RF module and brings it back to baseband data rates before transmitting it to the terrestrial network via the transport module. Coordination between these three functions is maintained by a control module.
In recent times, vendors have produced multi-radio versions of the base station, with software support for multiple radio interfaces from the same base station. This technology is often deployed to support what is known as the Single Ran architecture.
