Home' RTCA Documents for Review : DO-343B Contents © RTCA, 2018
Each network which accesses the satellite will also provide an independent equivalent
set of functions to the SBB Network-specific Radio Network Subsystem, which may
use different naming conventions.
Satellite Specific Functions
The Tracking, Telemetry and Control (TT&C) functions are responsible for monitoring
the satellite bus and all aspects of health of the satellite, and provide security
mechanisms and modems that allow the satellite payload to be configured by the
Payload Control System.
The Payload Control System (PCS) is specifically responsible for managing the satellite
payload. This includes configuring the beam forming networks and transponder
frequency and gain settings to create spot beams and to illuminate these beams with
200 kHz sub-bands.
The Global Resource Manager (GRM) is responsible for arbitrating requests for sub-
bands in each beam from various Radio Network Subsystems. The GRM is able to
perform dynamic optimization of the macro-level resources to minimize interference
into each sub-band. The GRM works within constraints set by the frequency plan,
maintains a view of the resource utilization in each beam by each RNS and has the
capability to instruct an RNS to release sub-bands if required.
The Frequency Planning Subsystem (FPS) is responsible for establishing the time-of-
day based frequency plan which defines the degrees of freedom under which the GRM
is able to operate. Certain frequencies will be allocated on a static basis to each RNS,
whereas others will either be able to be manoeuvred within different beams or between
different RNS entities on a demand assigned basis.
The Radio Frequency Subsystem (RFS) provides the RF uplink and downlink capability
for both TT&C functions and RNS subsystems, and include all antenna control
mechanisms, High Power Amplifiers, Low Noise Amplifiers, RF Level Control and up-
conversion and down-conversion and IF distribution infrastructure. It is possible that
RFS subsystems may be deployed on different sites for redundancy purposes, and the
TT&C functions and RNS functions may be operated via independent RFS
Radio Network Subsystem
The RNS implements the SBB 3G Network Specific Functions that can be broadly split
into the Channel Unit Subsystem (CUS) and Radio Network Controller (RNC) functions.
The Channel Unit Subsystem provides banks of transmit and receive modems
configured on independent Transmit (Tx) and Receive (Rx) Channel Cards (six
modems per card). The modems within each Channel Card are capable of handling a
single 200 kHz sub-band. These Channel Cards are deployed in banks which access
the various IF distribution feeds from the RFS. Each bank of Channel Cards is
deployed in a 1-for-n redundancy on a shelf basis.
The Radio Network Controller comprises a number of internal entities, including the
Host Controller (hot standby 1:1 redundancy).
Core Network Gateway (hot standby 1:1 redundancy).
Main Control Processor (1:n redundancy).
The Host Controller performs a number of functions, including:
Interfacing to the GRM to obtain satellite resources for operation.
Configuring Channel Unit Subsystem with sub-bands.
Broadcasting system information.
Controlling initial mobile terminal access (registration) to the Radio Access
Maintaining state information for the mobile terminals registered with the RAN.
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