3GPP specification for 5G NR defines the three classes for base station namely, Wide Area Base Station, Medium Range Base Station and Local Area Base Station.
These classes are corresponding to the Macro cell, Micro cell and Pico cell very well know cell types deployments. 3GPP has specified these classes to make sure that certain radio characteristics are in limits and suitable for specified deployment. These radio characteristics can be maximum allowed transmit power, minimum receiver sensitivity minimum distance between UE and or minimum coupling loss support.
Transmit Power Capability of Each Class
- Wide Area Base Station : No upper limit transmit power [ but each country has it allowed EIRP limit for RF regulations]
- Medium Range Base Station : < 38dBm or 6.3 watts
- Local Area Base Station: <24 dBm or 0.25 watts
Minimum Coupling Loss Requirements
Base Stations Type 1-C and 1-H are classified into Wide Area, Medium range and Local Area classes considering their minimum coupling loss requirements for each class. The minimum coupling loss can be defined as the minimum path loss measurement between the base station antenna connector and UE antenna connector in dB, it is denoted by MCL.
The MCL is measured at reference port A or B in case of Type 1-C base station and at TAB connector in case of Type 1-H. Below is the range for MCL to each base station class
- Wide Area Base Station : MCL of 70 dB
- Medium Range Base Station : MCL of 53 dB
- Local Area Base Station: MCL of 45 dB
Minimum Distance between Base Station and UE
In base station Type 1-O and 2-O, the transceiver, RDN and Antenna array resides in with one box and does not have any RF connector or reference point at base station to perform the measurements. These types of base station also classified as Wide Area, Medium range and Local Area based on the minimum distance in meters between base stations and UE. This distance is measurement from Radiated Interface Boundary (RIB).
Below is the minimum distance requirement between base station and UE.
- Wide Area Base Station : 35m
- Medium Range Base Station : 5m
- Local Area Base Station: 2m
- 3GPP TS 38.104; NR; Base Station (BS) radio transmission and reception ( version 15.2.0 Release 15)
- 5G NR Base Station Types