Radio Frequency (Rf) Subsystem; Radio Frequency Terminal; Uplink Subsystem; Satellite Gateway - Hughes HX System System Overview

Radio frequency (RF)
subsystem

Radio frequency terminal

Uplink subsystem

Satellite gateway

Chapter 2 • Subsystems
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configured with a maximum total CIR to limit the IP traffic to the
customer's contracted grade of service.
Depending on the size of the network, there may be many IP
gateways within a single HX System gateway. Typically, the HX
gateway contains at least one IP gateway for each inroute
subsystem.
The RF subsystem performs the actual transmission and reception
of satellite signals. The RF subsystem delivers received satellite
signals to the inroute subsystems at RF. It takes outroute signals
in the DVB asynchronous serial interface (ASI) format and
modulates and transmits those signals. The RF subsystem is
managed via SNMP using the management LAN and is internally
redundant. The RF subsystem consists of the radio frequency
terminal (RFT) and the system IF distribution module, which use
commercial, off-the-shelf equipment.
The RFT takes the uplink intermediate frequency (IF) output of
the system IF distribution module, upconverts it to radio
frequency (RF) and transmits it to the satellite. The RFT also
receives from the satellite the RF echo of the transmitted signal,
along with the RF input for the inroutes, downconverts the signals
to IF and forwards the downconverted signals to the system IF
distribution module and then to the downlink subsystem. The
RFT is made up of commercial off-the-shelf products.
The uplink (or outroute) subsystem performs the multiplexing
and transmission of all outbound IP traffic. All outbound traffic is
formatted to conform to the DVB-S or DVB-S2 standard.
The outroute subsystem is made up of satellite gateways, DVB
modulators, and outroute redundancy equipment.
The satellite gateway (SATGW) receives bundled satellite traffic
from the other NOC components over a LAN segment, formats
the information into individual packets, and forwards them to the
DVB modulator for transmission over the satellite.
The satellite gateway receives bundled satellite traffic over the
satellite LAN from the following components:
• IP gateways (including management gateways)
• DNCCs
• Special services gateways (SSGW)