Week 3 : Spectrum and its uses

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

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 1020 Hz AC Broadcast Microwave Infrared Ultraviolett X-Ray

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 30-300 KHz 6 MF, Medium frequency 300-3000 KHz 7 HF, High frequency 3-30 MHz 8 VHF, Very high frequency 30-300 MHz 9 UHF, Ultra high frequency 300-3000 MHz Decimetric waves Centimetric waves 10 SHF, Super high frequency 3-30 GHz 11 EHF, Extra high frequency 30-300 GHz Decimillimetric waves

Satellite Operating Frequency Bands Frequency Range (GHz) Band Category 0.39-1.55 L MSS 1.55-5.2 S FSS & BSS 3.9-6.2 C FSS 5.2-10.9 X Military 10.9-36.0 K FSS & BSS 15.35-17.25 Ku FSS & BSS 18.3-31.0 Ka FSS FSS Fixed Satellite Services BSS Broadcats Satellite Services MSS Mobile Broadcast Services

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.

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

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

Frequency Allocations to Satellite Services

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

International Telecommunications Union (ITU) Article S5 of Radio Regulations Region 1 Region 2 Region 3 19.7 - 20.1 GHz FIXED-SATELLITE (space-to-earth) 19.7 - 20.1 GHz FIXED-SATELLITE (space-to-earth) 19.7 - 20.1 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

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’

Week 4. Carrying Information (Link Budget)

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

Link Budget

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

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

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

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

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

Receiving Earth Station

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)

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

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

Noise Calculation LO : Local Oscilator (Function Generator)

Thermal Noise The noise of a system generated by the random movement of electronics, is expressed as Noise Power = KxTxB Where, K= (-228.6 dBJ/K) T= Equivalent Noise Temperature (K) B= Noise Bandwidth of a receiver

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

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

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

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]