1. Week 3 : Spectrum and its uses

2. Frequency Allocations & Regulatory Aspects
• Frequency bands for satellite services are shared with terrestrial services.
• Satellite signal strength is constrained to avoid interference by it to others.
• Thus a large antenna and sensitive receiver are needed at the earth station.
• Frequency sharing techniques are an important study area.
• Many satellites have to share a limited frequency band (and limited orbital location) thus coordination in frequency and orbital location is important.
• Frequency allocation are done by international agreements

3. The Frequency Spectrum and Typical Applications
Power
GPSMobil
Glonass
Systems
Mittel
GalileoFunk
Sat
Welle TV AM UKW
Mikro TV Welle IR Lamp
Sun X-Rays
Studio
102
104
106
108
1010
1012
1014
1016
1018 Hz AC
Broadcast Microwave
Infrared
Ultraviolett
X-Ray

4. Radio Frequency Bands Band Number Band Name Frequency Range
Metric Subdivision
4 VLF, Very low frequency 3-30 KHz
Myriametric waves Kilometric waves Hectometric waves Decametric waves Metric waves
5 LF, Low frequency KHz
6 MF, Medium frequency KHz
7 HF, High frequency 3-30 MHz
8 VHF, Very high frequency MHz
9 UHF, Ultra high frequency MHz
Decimetric waves Centimetric waves
10 SHF, Super high frequency 3-30 GHz
11 EHF, Extra high frequency GHz
Decimillimetric waves

5. Satellite Operating Frequency Bands
Frequency Range (GHz)
Band
Category L
MSS S
FSS & BSS C
FSS X
Military K
FSS & BSS Ku
FSS & BSS Ka
FSS
FSS Fixed Satellite Services
BSS Broadcats Satellite Services
MSS Mobile Broadcast Services

6. Frequency Allocation and Regulatory Aspects
• Domestic
e.g. Federal communication Commission (FCC)
National Telecommunication and Information Administration (NITA)
In Pakistan, PTA (Pakistan Telecommunication Authority)
• International
International Telecommunication Union (ITU)
- Formed in 1932 from the International Telegraph Union
- Consists of over 150 members nations
- World Administrative Radio Conference (WARC)
- International Radio Consultative Committee (CCIR) consists of 13 study groups.

7. ITU Regions
ITU divides the surface area of the earth into 3 regions for the purpose of frequency allocation
• Region 1: Pacific Ocean Region North and South America
Greenland
• Region 2: Atlantic Ocean Region Europe
Africa
Middle East Central Asia

8. ITU Regions (Continued)
• Region 3: Indian Ocean Region

9. Frequency Allocations to Satellite Services

10. International Telecommunications Union
Examples of Satellite Radio Services: -
Fixed Satellite Service
FSS -
Mobile Satellite Service
MSS -
Broadcast Satellite Service BSS -
Radio Navigation Sat. Serv RNSS -
Radio location Sat. Service RSS -
Space Operation Service
SOS -
Earth observation Sat. Serv ESS
In total more than 18 radio services

11. International Telecommunications Union (ITU)
Article S5 of Radio Regulations
Region 1
Region 2
Region 3
GHz FIXED-SATELLITE (space-to-earth)
GHz FIXED-SATELLITE (space-to-earth)
GHz FIXED-SATELLITE (space-to-earth)
Mobile-Satellite (space-to-earth)
MOBILE-SATELLITE (space-to-earth)
Mobile-Satellite (space-to-earth)
S5.524
S5.524, S5.525, S5.526 S5.527, S5.528, S5.529
S5.524

12. International Telecommunications Union
A license is required by every operator in order to operate a satellite system nationally; a licence may only be taken if:
- the operator can show that he has a contract with the system owner to be his service provider
- the frequencies for the system have been cleared / coordinated / notified
- that system is fully registered with the ITU
-the operator has workers registered as operators A licence will be cancelled if:
- there are no more registered operators to work the system
- the service provider has breached ‘data protection laws’

13. Week 4. Carrying Information (Link Budget)

14. Contents • Introduction • General Architecture
• Signal Power Calculation
• EIRP (Effective Isotropic Radiated Power)
• Noise Calculation
• Thermal Noise
• Effective Temperature
• Noise Temperature
• G/T (Antenna Gain to Receiver Noise Temperature)
• Link Analysis
• Rain Attenuation and Margin b o
• Carrier Parameters
• BER

15. Link Budget

16. Introduction Overall design of a complete satellite communications
system involves many complex trade-offs to obtain a cost- effective solutions
Factors which dominate are
-Downlink EIRP, G/T and SFD (Saturated Flux (flow) Density)
of Satellite
-Earth Station Antenna
-Frequency
-Interference

17. General Architecture Uplink Downlink EIRP down G/T & SFD
Downlink Path Loss Rain Attenuation
Uplink Path Loss Rain Attenuation
EIRP Up
G/T Gt Pt
LNA / LNB
HPA / Transceiver

18. Transmit Earth Station
-Antenna Gain
-Power of Amplifier Uplink
-Path Loss
-Rain Attenuation

19. Satellite Downlink -G/T ((Antenna Gain to Receiver Noise Temperature))
-EIRP (Effecive Isotropic Radiated Power)
-SFD (Saturated Flux Density)
-Amplifier Characteristic
Downlink
-Path Loss
-Rain Attenuation

20. Receiving Earth Station
-Antenna Gain
-LNA /LNB Noise Temperature c
Other Equipment
LNA : Low Noise Amplifier
LNB : Low Noise Blocker

21. Receiving Earth Station

22. Signal Power Calculation
Antenna Gain
G = η (pi* d / λ) 2
[dBi]
Where, λ = C / f ,
C = Speed of light
f = frequency of interest
η = efficiency of antenna (%), d = diameter of antenna (m)

23. EIRP EIRP = Gt + Pt -Lf [dB] Where, Lf is the Feed Losses
Is the effective radiated power from the
transmitting side and is the product of the antenna gain and the transmitting power,
expressed as
EIRP = Gt + Pt -Lf
[dB]
Where,
Lf is the Feed Losses

24. Signal Power (Pr) Pr = EIRP - Path Loss + Gr (sat) [dB] Where,
Path Loss = (4*pi*d / λ) 2
D is in meters (m)

25. Noise Calculation
LO : Local Oscilator (Function Generator)

26. Thermal Noise
The noise of a system generated by the random movement of electronics, is expressed as
Noise Power = KxTxB
Where,
K= ( dBJ/K)
T= Equivalent Noise Temperature (K) B= Noise Bandwidth of a receiver

27. Effective Temperature
Te = T1 + (T2/G1)
Where,
T1= Temperature of LNA T2= Temperature of D/C G1= Gain of LNA

28. Noise Temperature Ts = Tant / Lf+(1-1/Lf)Tf Where ,
Tant = Temperature of antenna Lf = Feed Losses
Tf = Feed Temperature

29. Effective Temperature
Tsys = Ts + Te
• Being a first stage in the receiving chain, LNA is the major factor for the System Temperature Calculation
• Lower the noise figure of LNA lower the system temperature
• Antenna temperature depends on the elevation angle from the earth station to satellite

30. G/T (Gain to System Noise Temperature)
- This is the Figure of merit of any receiving system
- It is the ratio of gain of the system and system noise temperature
G/T = G-10log (Tsys)
[dB/K]