A LABORATORY SYSTEM FOR THE INVESTIGATION OF RAIN FADE COMPENSATION TECHNIQUES FOR Ka-BAND SATELLITES
نویسندگان
چکیده
The design and performance of a rain fade simulation! counteraction system on a laboratory simulated 30/20 GHz, time division multiple access (IDMA) satellite communications testbed is evaluated. Severe rain attenuation of electromagnetic radiation at 30/20 GHz occurs due to the carrier wavelength approaching the water droplet size. Rain in the downlink path lowers the signal power present at the receiver, resulting in a higher number of bit errors induced in the digital ground terminal. The laboratory simulation performed at NASA Lewis Research Center uses a programmable PIN diode attenuator to simulate 20 GHz satellite downlink geographic rain fade profiles. A computer based network control system monitors the downlink power and informs the network of any power threshold violations, which then prompts the network to issue commands that temporaril y increase the gain of the satellite based traveling wave tube (TW1) amplifier. After the rain subsides, the network returns the TWT to the normal energy conserving power mode. Bit error rate (BER) data taken at the receiving ground terminal serves as a measure of the severity of rain degradation, and also evaluates the extent to which the network can improve the faded channel.
منابع مشابه
Special Effects: Antenna Wetting, Short Distance Diversity and Depolarization
The Advanced Communication Technology Satellite (ACTS) communications system operates in the Ka frequency band. ACTS uses multiple, hopping, narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for bit-error-rates of 5x 10 or better over the continental United States. In order maintain this minimum system availability in all US rain zones, ...
متن کاملA Prototype Adaptive Fade Countermeasure System for TDMA Operation at Ka Band
Ka band, the 20/30 GHz frequency band for satellite communications, has gained much interest in recent times. It is well suited for applications with small sized earth stations. The major disadvantage of Ka band, however, is its sensitivity to rain fading. Several satellite experiments are being carried out at the moment studying so called adaptive fade countermeasures, the purpose of which is ...
متن کاملKa-Band Propagation Measurements: An Opportunity with the Advanced Communications Technology Satellite (ACTS)
The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) as a follow-on program to its long history in satellite communications projects that have reduced the risk of developing new technologies that fall outside the sponsorship capability of the private sector. To counter the foreign challenge that developed in the late 1...
متن کاملOn the Outage Probability Prediction of Time Diversity Scheme in Broadband Satel- Lite Communication Systems
A novel model for the outage probability prediction in time diversity satellite communication (SatCom) systems operating above 10GHz is proposed. Due to the migration of operating frequency at Ka band and above, atmospheric phenomena affect the signal. Rain is the dominant fading mechanism. Diversity techniques are the probable solution of the compensation of rain fading. Among the diversity te...
متن کامل