Page 587 - 5G Basics - Core Network Aspects

Transport aspects 2

RAN Radio Access Network

RF Radio Frequency
RoF Radio over Fibre

RRH Remote Radio Head
RRU Remote Radio Unit

R/S Reference point at the interface of the ONU and the ODN
Rx Receiver
SA Signal Analyser

SC Soft Clipping
SCM Subcarrier Multiplexing

SG Signal Generator
SMF Single-Mode Fibre
SNI Service Network Interface

SNR Signal-to-Noise Ratio
S/R Reference point at the interface of the OLT and the ODN

SSMF Standard Single-Mode Fibre
TDM Time Division Multiplexing

Tx Transmitter
TWDM Time Wavelength Division Multiplexing

UNI User Network Interface
VEA Variable Electrical Attenuator
VOA Variable Optical Attenuator

VSA Vector Signal Analyser
VSG Vector Signal Generator

W-CDMA Wideband Code Division Multiple Access
WDM Wavelength Division Multiplexing
Wi-Fi Wireless Fidelity

WiMAX Worldwide Interoperability for Microwave Access
WM Wavelength Multiplexer

5 General concept

The current deployment of radiocommunication services shows a tendency towards higher bit rates with
higher radio carrier frequencies, compared to those in the legacy radiocommunication services, in order to
satisfy customer demands for broadband access. To realize such radiocommunication services, a cell size
covered by one radio access point must be smaller from the physical viewpoint, leading to drastic increases
in the number of antennas serving as radio access points. In addition, there exist many areas inaccessible to
radio waves ("radio shadow" areas), such as underground spaces (subterranean structures), tunnels, areas
behind buildings, upper stories of skyscrapers, dips below ground level in metropolitan areas and within
mountainous regions. To support small cell radio communications and radio shadow countermeasures,
many RoF technologies have been actively studied and deployed in the research and development of

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