Page 609 - 5G Basics - Core Network Aspects

Transport aspects 2

The total number of RoF signals is considered in order to categorize RANs into types, taking fibre assets and
fibre topologies of optical distribution network (ODN) into account. First, the existing definitions of three
RAN scenarios as a function of cell structure and coverage are as follows.
A macro cell (see definition in clause 3.1.3) is compliant with the Third Generation Partnership Project
(3GPP) standard, a few 10s of watts RF output power level, several radio technologies and several cells
sectors to achieve a large coverage.

A micro cell (see definition in clause 3.1.2) is compliant with the 3GPP standard, a few 10s of watts RF
output power level, several radio technologies and typically one cell sector to achieve a specific coverage
area.

A pico cell (see definition in clause 3.1.5) can be one flavor configuration of small cell.
For our RoF topic, the small cell (3.1.4) is compliant with the 3GPP standard, low-power RF transmission
(with varying output power ranging from 0.5 W to a few watts), one or several radio technologies and one
cell sector to achieve a specific coverage area.

These three radio configuration descriptions allow it to be understood that several RF combinations could
be implemented for each scenario. In order to achieve a classification for RoF applications, the parameters
required for counting the number of RoF signals are clarified. There are four parameters.

The number of radio technologies (NRT): This corresponds to the kind of radio (especially mobile)
communication standards and their generations, such as the global system for mobile communications
(GSM), wideband code division multiple access (W-CDMA), code division multiple access-2000
(CDMA-2000), long term evolution (LTE), LTE-A, worldwide interoperability for microwave access (WiMAX)
and WiMAX2.

The number of RF bands allocated in one radio technology (NRFB, where RFB denotes radio frequency
block): W-CDMA (FDD) and LTE have many RF bands, which are defined in [b-3GPP TS 25.101] and
[b-3GPP TS 36.101], such as band 1 (2 100 MHz band), band 2 (1 900 MHz band), band 5 (850 MHz band)
and band 8 (900 MHz band).
The number of radio sectors (NRS): This is applicable only for cells with sector antennas.

The number of multi-input multi-output (MIMO) signals (NMIMO): In LTE and LTE-A systems, the MIMO
technology must be supported. In the specific case of digital RoF, the present implementation supports the
processing of all the MIMO signals in a single RoF signal (NMIMO = 1).

These two descriptive ways of RANs are used to understand the applicability of proposed ODNs, network
interface and transmission mechanisms for RoF signals.

In clauses 8.1 to 8.5, unless stated otherwise, the expression "RoF signal" concerns analogue and digital
RoF.

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