Chapter 8 • Transmission features
1037852-0001 Revision A
65
Closed loop control
The Hughes HX System has a
closed loop power control
between
the HX gateway and satellite routers so that there is a continuous
monitoring of the outbound and inbound channels. As shown in
Figure 15, the closed loop control provides for the HX gateway to
continuously monitor the received signal quality of transmissions
from each satellite router while each satellite router continuously
monitors the received signal quality of the transmission from the
HX gateway. As atmospheric conditions affect the link quality,
each component is able to request changes to overcome fade
conditions.
At the gateway, the outbound channel coding and modulation can
be varied dynamically, while at the satellite router the forward
error correction (FEC) coding can be varied dynamically to
improve link availability. If the satellite router needs a more
robust link performance for the inbound transmissions, it has the
ability to shift to a different inroute group supporting a lower
symbol rate. Note that the latter capability does not exist when
operating with CBR IQoS plans. Additionally, the satellite router
can dynamically change its local uplink power control to
overcome fade conditions.
Closed Loop Timing
As part of the closed loop control implementation, the HX
System also supports closed loop timing (CLT) which allows for
both mobility of operation as well as
spot beam
satellite
operation.
Figure 15: HX System closed loop power control
HX GTWY measures received
s
s
b
t
o
r
r
ignal trength and urst
iming ffset eceived
from emote
GTWY sends
adjustments to
HX remote
HX remote
continually
measures
received
signal quality
G-28735 C
08/22/06
Содержание HX System
Страница 1: ...1037852 0001 Revision A September 4 2008 HX System System Overview Release 1 2 7 ...
Страница 8: ... Contents viii 1037852 0001 Revision A ...
Страница 10: ... Figures x 1037852 0001 Revision A ...
Страница 12: ... Tables xii 1037852 0001 Revision A ...
Страница 24: ...Chapter 1 Overview 12 1037852 0001 Revision A ...
Страница 26: ...Chapter 2 Subsystems 14 1037852 0001 Revision A Figure 3 HX Subsystems and LAN Connections ...
Страница 40: ...Chapter 3 Network management 28 1037852 0001 Revision A Figure 4 Network management system and LAN connections ...
Страница 50: ...Chapter 4 Network security 38 1037852 0001 Revision A ...
Страница 62: ...Chapter 5 Bandwidth management 50 1037852 0001 Revision A ...
Страница 70: ...Chapter 6 IP features 58 1037852 0001 Revision A ...
Страница 80: ...Chapter 8 Transmission features 68 1037852 0001 Revision A ...
Страница 88: ...Chapter 10 HX options 76 1037852 0001 Revision A ...
Страница 96: ...Appendix B Transportable Gateway TGW 84 1037852 0001 Revision A ...
Страница 100: ... Acronyms and abbreviations 88 1037852 0001 Revision A ...
Страница 106: ... Index 94 1037852 0001 Revision A ...