ACP WGF23/IP26
Abdolmajid Khalilzadeh
FIXED SATELLITE SERVICE
and
UAS
(22 September 2010)
1
COMMERCIAL SATELLITES
• The FSS may be able to fulfill the UAS spectrum
requirements without the need for a new
AMS(R)S allocation
• Existing commercial FSS systems at Ku and Kaband offer immediate access to spectrum for
UAS
• ITU-R studies have shown that the commercial
Ku/Ka bands can support UAS control links and
meet the desired UAS link availability.
2
UAS OPERATING UNDER FSS
• Requires modification of ITU Radio Regulations
to permit UAS to communicate with a FSS
satellite
• Requires a WRC Resolution that contains the
UAS technical and regulatory requirements
• The performance, responsibilities and liabilities
of the FSS and UAS operators would be
specified in a commercial contract
• UAS would not be operating under the AMS(R)S
service allocation, but rather as an FSS
application
3
Non-Planned Ku Band FSS
Frequencies
• Space-to-Earth Direction
10.95 – 11.20 GHz
11.45 – 11.70 GHz
11.70 – 12.20 GHz (Region 2)
12.20 – 12.50 GHz (Region 3)
12.50 – 12.75 GHz (Regions 1 and 3)
• Earth-to-Space Direction
14.00 – 14.50 GHz
4
Non-Planned Ka Band FSS
Frequencies
• Space-to-Earth Direction
17.30 – 17.70 GHz (Region 1)
17.70 – 18.80 GHz
19.70 – 21.20 GHz
• Earth-to-Space Direction
27.50 – 28.60 GHz
29.50 – 31.00 GHz
5
SATELLITE CHARACTERISTICS
•
•
•
•
•
•
•
•
Long lifetime (≥ 15 years)
Low satellite and transponder failure rates
High EIRP and G/T levels over large geographic areas
Well suited for links that utilize small transmit/receive
antennas
High radio link availability
Connectivity over large geographic areas, which
terrestrial links cannot provide
Multiple transponders are available on each satellite, e.g.
24 Ku-band 36 MHz transponders
Bandwidths typically range from 24 to 120 MHz – the
most common bandwidth being 36 MHz
6
SATELLITE COVERAGE
Uplink Coverage
+2
+4
Downlink Coverage
50.8
50.8
Ñ+6
52.8
48.8
48.8
0
-2
-4
46.8
44.8
42.8
+6
Note: This is an example coverage map; actual coverage varies depending on
actual satellite design.
7
COMMERCIAL SATELLITE
CAPACITY
• TRANSPONDER LEASING
– Customer can lease all or portion of a transponder
– Transponder can be leased on a non-premptible
basis
• Carrier cannot be moved to restore another carrier
• BACK-UP CAPACITY
– Due to large number of satellites and transponders,
back-up (bandwidth) capacity can be provided.
• Back-up capacity available on the same satellite
• Back-up capacity available on another satellite
8
LINK DEGRADATION
• A satellite link can be degraded by two
primary sources
– Atmospheric effects
– Adjacent satellite interference
• Typical commercial satellite link
availabilities range from 99.50% to 99.96%
9
ADJACENT SATELLITE
INTERFERNCE
• A satellite link is subject to interference
from the transmissions of other cofrequency satellite networks
• Interference can occur in the Earth-tospace direction or in the space-to-Earth
direction.
• Adjacent satellite interference are
managed through ITU coordination.
10
ADJACENT SATELLITE
INTERFERNCE
SAT 1
SAT 2
SAT 3
2º±0.05º
2º±0.05º
J
I
1
2
C
G
E
A
F
UA
H
ES1
D
B
4
3
ES2
ES3
Note: 2º orbital separation is typical of the separation between adjacent satellites
11
COORDINATION
• Satellite operators coordinate the maximum power and
EIRP density level of their transmissions, the off-axis
gain characteristics of their antennas and the placement
of any high power density carriers, e.g. TV/FM
– A known and stable interference environment
– Links are designed to withstand the expected interference
• Internationally, coordination agreements are contained in
a formal document that is approved by the involved
satellite operators and their respective administrations
• Domestically, a formal agreement may or may not be
required – depends on the regulations of each
administration
12
ATMOSPHERIC DEGRADATION
• Rain is the primary atmospheric source of link
degradation at Ku and Ka-band frequencies
• The effects of rain can be overcome in various
ways
– Increasing carrier power level
– Changing the carrier modulation & FEC scheme
– Increasing the transmitting and/or receiving antenna
size
• Typical commercial Ku-band link availabilities
range from 99.50% to 99.96%
13
UAS REDUNDANCY
• At some point in time, links will degrade or
drop-out for various reasons
• UAS systems need to incorporate
hardware redundancy
• UAS systems need to incorporate
spectrum redundancy
– Capacity
– Frequency
14