PAUL K LEE
Broker in Lexington, MA
License number
Massachusetts 9010507
Issued Date
Dec 10, 1994
Expiration Date
Aug 7, 2017
Type
Salesperson
Address
Address
Lexington, MA 02420
Professional information
Spectrum Efficient Fast Frequency-Hopped Modem With Coherent Demodulation
US Patent:
6584140, Jun 24, 2003
Filed:
Jan 22, 1999
Appl. No.:
09/235988
Inventors:
Paul K. Lee - Lexington MA
Assignee:
Systems Information and Electronic Systems Integration Inc. - Nashua NH
International Classification:
H04B 169
US Classification:
375132, 375261, 375265, 375298
Abstract:
A system for increasing data transmission capacity over a wireless mobile link while at the same time providing improved jamming resistance utilizes discrete trellis-coded modulation involving frequency hopping individual symbols, along with encoding the phase of a symbol as a frequency offset to the hopped carrier frequency. This modulation system permits coherent demodulation in which both phase and amplitude of a symbol is robustly decoded and in which each phase of a quadrature amplitude modulated signal is decoded by the detected frequency offset, thus to provide reliable recovery of phase in the demodulation section. The resulting system improves spectrum efficiency and permits fast frequency hopping for improved jamming resistance, with the utilization of frequency offset coding permitting the coherent demodulation that improves the error-rate without the introduction of additional reference bits.