GAUSSIAN MINIMUM SHIFT KEYING (GMSK) IS A CCSDS STANDARD SCHEME FOR SPACE MISSIONS REQUIRING VERY BANDWIDTH…

Public award description

GAUSSIAN MINIMUM SHIFT KEYING (GMSK) IS A CCSDS STANDARD SCHEME FOR SPACE MISSIONS REQUIRING VERY BANDWIDTH EFFICIENT COMMUNICATIONS USING TRANSCEIVERS WITH STRICT SIZE, WEIGHT, AND POWER RESTRICTIONS. GMSK PROVIDES A CONSTANT ENVELOPE SIGNAL THAT PASSES UNALTERED THROUGH SYSTEM NONLINEARITIES, ALLOWING EFFICIENT POWER AMPLIFIER OPERATION WITHOUT EXTENSIVE FILTERING AND PREDISTORTION. UNFORTUNATELY, CURRENT OFF-THE-SHELF GMSK AND RELATED CONTINUOUS PHASE MODULATION (CPM) RECEIVERS (E.G., MULTI-H CPM) OPERATE FAR FROM PREDICTED THEORETICAL PERFORMANCE AND SUFFER FROM FREQUENT LINK DROPOUTS. CPM PERFORMANCE ISSUES ARE MOSTLY ATTRIBUTABLE TO A FAILURE TO ADEQUATELY MODEL AND MITIGATE AGAINST TRANSMITTER, CHANNEL, AND RECEIVER IMPAIRMENTS, INCLUDING FIXED-POINT PROCESSING EFFECTS, AND TO GENERATE RELIABLE SOFT-DECISION INFORMATION FOR DECODING. TO MAXIMIZE PERFORMANCE GIVEN CCSDS TURBO OR LDPC CODING AND ELIMINATE COMMUNICATIONS DROPOUTS, A SOFT-DECISION GENERATING GMSK DEMODULATOR WITH CAREFULLY DESIGNED IMPAIRMENT ESTIMATION AND COMPENSATION IS PROPOSED.