This document discusses the design requirements and considerations for a satellite communication system operating in Ku-band. It outlines four key factors that drive earth station design: reliability, link budget, customer objectives, and special teleport considerations. The document then provides details on the system specifications, including parameters for the Ku-band satellite, transmitting and receiving earth stations. It also discusses link budget considerations and the effects of rain fading at Ku-band frequencies.

1. Satellite Communication
Topic : All System Design Example
Presented By
Abhilasha Kalmegh

2. Contents
• System Design Requirement
• Link Budget Consideration
• System and Satellite Specification
• Ku – Band Uplink Design
• Rain Effect at Ku - Band

3. System Design Requirement
• Four factors tend to drive Earth Station design. These are:
 Reliability and Availability
 Link Budget Considerations
 Customer Driven Objectives
 Special Considerations Applying to Teleports
• These considerations may sometimes be in conflict, and compromise
decisions must be made.
• As always, cost is also an issue, and all design choices must make good
business sense.

4. • Link Budget design is covered in detail in Volume 5 of this course. This
section will discuss how Earth Station design is affected by link budget
concerns, and will not cover the link budgeting process itself.
• A link budget is composed of primarily three segments:
– 1) The transmitting Earth Station and uplink characteristics
– 2) The satellite (transponder characteristics)
– 3) The receiving Earth Station and downlink characteristics
• There are no “right answers” to questions involving the design of two-way
satellite Earth Stations. Different solutions are a testament to individual
ingenuity within the design group.
Link Budget Considerations
Introduction

5. • These factors affect the engineering of satellite Earth Station uplinks:
Link Budget Considerations
Design Factors
• Error correction coding
• Frequency
• Path loss
• Adjacent satellite interference
• Operational reliability
• Kinds of environmental ingredients
• Receive Earth Station antenna size
• Noise temperature
• Satellite transponder parameters
• Modulation scheme
• Bandwidth
• Data rate

6. System and Satellite Specification
Ku Band satellite parameter
• Geostationary at 73◦ W longitude, 28 Ku-band transponders
• Total RF output power ----------- 2.24kW
• Antenna gain , on axis (transmit and receive ) ----------- 31dB
• Receive system noise temperature ----------- 500◦K
• Transponder saturated output power : Ku band ----------- 80W
• Transponder bandwidth : Ku band ----------- 54Mhz

7. Transmitting Ku-band earth station
• Antenna diameter ----------- 5 m
• Aperture efficiency ----------- 68 %
• Uplink Frequency ----------- 14.16 GHz
• Required C/N in Ku-band transponder ----------- 30 dB
• Transponder HPA output backoff ----------- 1 dB
• Miscellaneous uplink losses ----------- 0.3 dB
• Location: -2 dB contour of satellite receiving antenna

8. Receiving Ku-band earth station
• Downlink Frequency ----------- 11.45 GHz
• Receiver IF noise bandwidth ----------- 43.2 GHz
• Antenna noise temperature ----------- 30 K
• LNA noise temperature ----------- 110 K
• Required overall (C/N) in clear air ----------- 17 dB
• Miscellaneous downlink losses ----------- 0.2 dB
• Location: -3 dB contour of satellite transmitting antenna

9. Ku-Band Uplink Design

10. Ku-Band Uplink Design
• Uplink Noise Power Budget
• K = Boltzmann constant ----------- 228.6 dB W/K/Hz
• Ts = 500 K ----------- 27.0 dB K
• B = 43.2 MHz ----------- 76.4 dB Hz
• N = transponder noise ----------- 125.2 dB W
• Pr = power at transponder input --------- -95.2 dB W

11. Rain Effects at Ku Band
• Under condition of heavy rain, the Ku Band path to the satellite station
suffers an attenuation of 6 dB for 0.01% of the year.
• Uplink power control (UPC) could be implemented so that the earth
station transmitter output power is increased when the uplink attenuation
is estimated to have reached 3 dB.
• The extra expenses can be justified in the television distribution system
with many receiving stations.
UPLINK