AN OPTIMAL TIME-DEPENDENT RECEIVER FOR INTERFERENCE REJECTION

THIS SBIR PROJECT EXAMINES A NEW AND INNOVATIVE METHOD OF IMPLEMENTING A RECEIVER THAT HAS SUPERIOR PERFORMANCE OVER THAT OF CONVENTIONAL RECEIVERS IN REJECTING INTERFERENCE. THE IMPROVED INTERFERENCE REJECTION ALLOWS THE TRANSMITTER TO USE LESS POWER TO ACHIEVE THE REQUIRED BIT-ERROR RATE PERFORMANCE, AND HENCE REDUCES THE PROBABILITY THAT THE TRANSMITTER WILL INTERFERE WITH OTHER USERS OF THE SPECTRUM. THE NEW RECEIVER, CALLED THE OPTIMAL TIME-DEPENDENT RECEIVER (OTDR), IS DEVELOPED BY CONSIDERING A RECEIVER AS A TIME-VARYING FILTERING PROCESS. THE OTDR ISAN ADAPTIVE TIME-VARYING FILTER THAT IS OPTIMIZED TO HANDLE CHANGING SIGNAL CONDITIONS AND NONSTATIONARY INTERFERENCE. THE SUPERIOR PERFORMANCE OF THE OTDR IS OBTAINED BY EXPLOITING THE CYCLOSTATIONARY NATURE OF THE INTERFERENCE. THE OTDR IS CAPABLE OF PERFORMING DOWN CONVERSION, EQUALIZATION, MULTIPATH REJECTION, INTERFERENCE REJECTION, BAUD SAMPLING, SYNCHRONIZATION, AND SYMBOL CONVERSION ALL WITHIN THE SAME OPERATION. THE OTDR CAN BE CONFIGURED TO HANDLE A VARIETY OF MODULATION TYPES, ALL USING LITTLE OR NOADDITIONAL HARDWARE, AND THUS IS CAPABLE OF NUMEROUS AND VARIED MODES. THE OTDR IS IMPLEMENTED USING DIGITAL SIGNAL PROCESSING TECHNIQUES AND THE HARDWARE CAN BE MADE SMALL, RELIABLE, AND MAINTENANCE FREE. THE OBJECTIVE OF THIS SBIR PROJECT IS TO DETERMINE THE THEORETICAL AND EXPERIMENTAL PERFORMANCE OF THE OTDR IN SEVERAL REALISTIC COMMERCIAL SITUATION. THE EVALUATION WILLINCLUDE DETERMINING THE TRADE-OFFS IN THE OTDR SYSTEM DESIGN.