Both BTS and Node B are the last mile network elements that process the signals and information prior to transmitting through antennas to the air interface. Node B does that for UMTS (Universal Mobile Telecom System) or any other third-generation wireless technology while BTS does the same for GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), or any second-generation wireless technology. Both BTS and Node B are physically located in geographically remote locations and provide the signal coverage to those geographical areas.
What is BTS?
BTS is also referred to as Base Transceiver Station or Radio Base Station (RBS) or simply Base Station (BS), in general. Most commonly the term BTS is referred to any base station of any wireless technology, but it is used more specifically for the base station of 2nd Generation wireless technologies such as GSM and CDMA. BTS is a part of BSS (Base Station Subsystem) which connects with BSC (Base Station Controller) via Abis interface and connects with UE (User Equipment) or end user or handset via Um wireless interface with regards to GSM. Abis interface may be either E1/T1 or IP in the physical layer.
BTS consists of Baseband Processing Unit, Base Station Control Function (BCF), Physical Transmission Interface (E1/T1 port or Ethernet port), TRX (Transceiver) and PA (Power Amplifier), Antenna and Feeder System, Combiners, Duplexer and Power Supply and Alarm Extension Unit. Operation and Maintenance (O&M) channel and signal and user data flow through Abis interface via E1/T1 or IP in the physical layer. The data from BSC is processed at the Baseband Processing unit and the processed data is sent to RF (Radio Frequency) conversion or RF modulation at the TRX and Power Amplifier. Next, the RF modulated data stream is sent through combiners and duplexer to the Antenna system for EM (Electro Magnetic) wave conversion. Then it is transmitted to the air interface after applying some more gain to the signal at the Antenna. The BCF is doing some control of the BTS and its other functions, but the main radio related control is performed at the BSC.
What is Node B?
Node B is also called a BTS, in general. However, when used with third -generation wireless technology such as UMTS, NodeB is the correct word to refer the BTS. The term Node B was first introduced with the introduction of UMTS. NodeB is a part of UTRAN (Universal Terrestrial Radio Access Network). NodeB connects to the RNC (Radio Network Controller) via IuB interface. The UE is connected to NodeB through air interface called Uu where it can be WCDMA or any other 3G wireless technology.
The IuB interface may be ATM (E1/T1 at the physical layer), IP or Hybrid (ATM and IP). However, there is an increased controlling part attached to NodeB than BTS in terms of Processing and Radio management functions. The Baseband to RF conversion process is much similar to BTS and only wireless technology makes some differences.
What is the difference between BTS and Node B?
• BTS is the base station of 2nd Generation wireless technologies such as GSM and CDMA, but Node B is its 3rd Generation counterpart mainly of UMTS and WiMAX
• BTS connects to BSC via Abis interface while NodeB connects to RNC via IuB interface.
• The physical layer transmission between BTS and RNC is either E1/T1 or IP, but Node B and RNC are capable of Hybrid transmission of ATM (E1/T1 at layer 1) and IP in addition to the BTS’s supported methods of transmission.
• Node B performs more Radio and Baseband controlling function than BTS.