Satellite Channel Simulator
How to configure it to simulate satellite link under Ionospheric Scintillation
1. Introduction
The satellite channel simulator (SCS) system is multipath signal emulator .The system can emulate four satellite link. The radio link characteristics that system can emulate are channel path delay, path loss, multipath delay spread , Rayleigh, Rician ,Suzuki, Nakagami ,Doppler shift and phase shift .The system is configured with three path per link with total 12 paths and to emulate Forward and return link, diversity ,interference and duplex test .
The channel and path parameter can be entered or loaded directly to the SCS using keyboard monitors Through GUI screen or remotely by download them through file transfer.
The system mainly designed for RF mobile communication channel and provides a set of predefined test configuration for many wireless communication standard as NADC, CDMA and GSM.
2.System Description
The system is build from standard instrument .The standard system consists of two Fading emulator and a single delay Generator and Dual Synthesizer. The system can be equipped by Thermal noise generator as an optional to maintain very accurate signal to noise ratio.
The SCS system works by first applying the RF input signal to the Fading Emulator
To be down converted executed by the chosen fading type .Then the unconverted to 14MHz and applied to the Delay generator to apply delay ,Doppler shift and path loss.
Finally, the output returns to the Fading Emulator for up conversion to RF and output
Each Fading Emulator is configured with two channel ,three paths per channel .The Delay generator is configured with four channels and rhe delay Generator with four channels as in figure(1).
Figure(1). SCS Block Diagram
3.Available system configuration
3.1 Single Channel configuration; all paths with one RF input and single LO and the output appear on Channel 1.
3.2Dual /Common LO configuration; Both channel works on Channel 1 LO with different RF input and Two output on channel 1 and 2 .This configuration uses for duplex application .
3.3 Diversity configuration; the One RF input and single LO are routed to both two channels .The paths in each channel is faded independently .The RF output appears for both channels.
3.4Interference configuration; Two RF input, one for each channel, and single LO. The paths in each channel is faded independently .The RF output s for both channels are combined into single output.
3.5 Duplex Configuration; each has its RF input, LO and output . This configuration uses for duplex application when the uplink and down link are different
4.Operation Mode
4.1 Static mode
the paths parameters are set or modified from the GUS and store them in a file .Then these files can be used later to perform test. In the static mode the simulation can be divided into up to eight sequential segment .Each segment contains the display parameters and those display parameters can be modified while the file is running.
4.2 Dynamic Mode
The Uses to emulate multipath environment contains mobile transceiver two base station, reflecting objects, shadowing objects and access nodes In this mode in real time at 40 ms interval according to the location and parameters of the objects the paths parameters are updated automatically .The environment's objects can represent through a map or table
5. Technical Specification
The main Technical Specification is;
| RF Input Signal Frequency Range | 1010-1661 MHz |
| RF Bandwidth | 10 MHz min |
| Number of Link (Ch1& Ch2)* | 2 forward 2 return |
| Number of Independent RF Path per Link | 3 |
| RF Input Signal Level | +1.2 dBm max |
| RF BW Peak to Peak Amplitude Variation | |
| Typical | 1 dB |
| Maximum | 2 dB |
| Physical Interface | |
| Connector Type | BNC |
| Input power | |
| 120 VAC | 4A fuse |
| 220 | 2A fuse |
| Remote control interface | |
| Fading Emulator | IEEE-488.2 |
| Delay Generator | Ethernet (IEEE-802.3) |
* Each Channel contains logically two link one forward and one return .Both controlled by on Fading Emulator unit and can be specify depend on configuration. If we choose Single Channel configuration all paths become forward or return.
6.Configure SCS to simulate satellite link under Ionospheric scintillation
6.1 Installation
The Fading Emulator can be setup to Single Channel configuration to simulate all paths with one RF input and single LO and the output appear on Channel 1 by choosing that from configuration and then single channel from GUI menu
6.2 Setup the channel
by setting the following parameters to new static file :
| Parameters | value |
| Channel | 1 |
| RF Input Signal center Frequency | 1500 MHz (example) |
| Time Duration | 1 hours |
| Initial delay | 0 |
| Output attenuation | 0 dB |
| Vehicle speed | 0 Km/h |
| Number of time a file run | Continuous run |
| Number of segment | 8* |
| Path 1 parameters | |
| Fading Type | Nakagami |
| Speed | 0 |
| Loss (dB) | 10 (example) |
| Delay | 0 |
| Correlation with | None |
| Correlation % | 0 |
| Phase offset | 0 |
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