MULTI-RATE TRELLIS-CODED MODULATION FOR MULTIPATH FADING CHANNELS

Award Information
Agency: National Science Foundation
Branch: N/A
Contract: N/A
Agency Tracking Number: 17320
Amount: $49,965.00
Phase: Phase I
Program: SBIR
Awards Year: 1992
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
Ensco, Inc
5400 Port Royal Road, Springfield, VA, 22151
DUNS: N/A
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Jay M. Jacobsmeyer
 (719) 598-1117
Business Contact
Phone: () -
Research Institution
N/A
Abstract
MULTIPATH FADING ON RADIO CHANNELS SERIOUSLY HAMPERS HIGH SPEED DIGITAL COMMUNICATIONS. TIME-VARYING AMPLITUDE AND PHASE FORCE CONVENTIONAL SYSTEMS TO OPERATE AT DATA RATES FAR BELOW CHANNEL CAPACITY. DIVERSITY AND ERROR-CORRECTION CODING TECHNIQUES HAVE NOT SOLVED THE PROBLEM COMPLETELY ANDHAVE INTRODUCED UNDESIRABLE SIDE EFFECTS IN THE PROCESS. WEPROPOSE TO INVESTIGATE A NEW APPROACH THAT ADAPTS THE SYSTEM DATA RATE TO THE TIME-VARYING SIGNAL-TO-NOISE RATIO AT THE RADIO RECEIVER. OUR RESEARCH OBJECTIVES ARE TO INVESTIGATE THE FEASIBILITY OF RATE CHANGING ALGORITHMS AND ADAPTIVE SYNCHRONIZATION; DEVELOP A MEASURE OF WAITING TIME PERFORMANCE; AND DETERMINE THE EFFECTS OF QUEUING, A NOISY FEEDBACK CHANNEL, RATE CHANGING OVERHEAD, AND PROPAGATION DELAY. OUR APPROACH EMPLOYS TRELLIS CODED MODULATION IN AN ADAPTIVE SCHEME WHERE THE DATA RATE VARIES BY CHANGING THE NUMBER OF BITS PER CHANNEL SYMBOL. PRELIMINARY RESEARCH INDICATES THAT THIS TECHNIQUE WILL PROVIDE CODING GAINS ON THE RAYLEIGH FADING CHANNEL OF 37 DB(@ BIT-ERROR-RATE = 10(-5) WITHOUT BANDWIDTH EXPANSION AND WITHOUT INTERLEAVING. POTENTIAL APPLICATIONS INCLUDE CELLULAR RADIO AND LINE-OF-SIGHT MICROWAVE RADIO. IF SUCCESSFUL, THIS RESEARCH WILL CONTRIBUTE TO THE UNITED STATES' TECHNICAL COMPETITIVENESS, ESPECIALLY IN DIGITAL MICROWAVE RADIO WHERE OUR PRINCIPAL COMPETITOR IS JAPAN.

* information listed above is at the time of submission.

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