POWER & BAND WIDTH EFFICIENT DIGITAL COMMUNICATIONS

Award Information
Agency:
National Aeronautics and Space Administration
Branch
n/a
Amount:
$49,847.00
Award Year:
1990
Program:
SBIR
Phase:
Phase I
Contract:
n/a
Agency Tracking Number:
12082
Solicitation Year:
n/a
Solicitation Topic Code:
n/a
Solicitation Number:
n/a
Small Business Information
Scs Telecom, Inc.
107 Haven Avenue, Port Washington, NY, 11050
Hubzone Owned:
N
Socially and Economically Disadvantaged:
N
Woman Owned:
N
Duns:
n/a
Principal Investigator:
Gary Lomp
Dept Head Systems Analysis
(516) 883-0760
Business Contact:
DONALD L. SCHILLING
PRESIDENT
(516) 883-0760
Research Institution:
n/a
Abstract
EXISTING DIGITAL RADIO SYSTEMS USE CONTINUOUS PHASE, FREQUENCY MODULATION TECHNIQUES WITH COHERENT DETECTION. THESE SYSTEMS MUST TRADE SPECTRAL EFFICIENCY FOR LOW BIT ERROR RATE AND IN CERTAIN APPLICATIONS SUCH AS SATELLITE AND MOBILE TELEPHONE ARE SUBJECT TO DEGRADATION DUE TO MULTIPATH. WE PROPOSE TO INVESTIGATE THE USE OF TRELLIS CODING OF THE SIGNAL SPACE WITH CP-FM, USING PLL DEMODULATION. THIS INNOVATIVE CODING SCHEME WILL BE APPLIEDFOR BOTH SYMMETRICAL AND ASYMMETRICAL SIGNAL CONSTELLATIONS. WE WILL INVESTIGATE SYSTEM PERFORMANCE IN THE PRESENCE OF FADING, MULTIPATH, DOPPLER INTERFERENCE AND NARROWBAND FILTERING OF THE FM SIGNAL. THESE EFFECTS CAUSE NONLINEAR DISTORTION OF THE MODULATION AND TEND TO CLOSE THE "EYE" OF THE DEMODULATED DATA. SCS HAS PERFORMED INITIAL RESEARCH USING A NONLINEAR ADAPTIVE EQUALIZER WHICH OPENS THE "EYE". FINALLY, WE WILL SELECT, THE OPTIMUM MODULATION SCHEME FOR A GIVEN CODE RATE. A SUCCESSFUL EFFORT WILL RESULT IN FAR MORE EFFICIENT COMMUNICATIONS SYSTEMS FOR THE SPACE STATION. THESE COMMUNICATION SYSTEMS WILL REQUIRE LESS POWER FOR THE SAME BER; REDUCED WEIGHT; HIGHER RELIABILITY; IMPROVED SPECTRAL EFFICIENCY TO REDUCE COSITE AND ADJACENT CHANNEL INTERFERENCE; BETTER MULTIPATH PERFORMANCE; AND LOWER COST.

* information listed above is at the time of submission.

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