Abstract
In 1977, Cooper and Nettleton proposed a spread spectrum mobile radio system using frequency-hopping multiple access, Hadamard coding for error correction, and differential phase shift keyed (DPSK) modulation, and they claimed higher spectral efficiency than frequency-division (FD) FM systems. Subsequent analyses showed that the DPSK system has a spectral efficiency of 8.4 percent as compared to the efficiency of unity for a FD-FM system with 30-kHz channel spacings. Goodman et al. suggested an alternative modulation scheme in 1980, using multilevel frequency shift keying (MFSK), and a 30 percent efficiency was obtained. The research results in spread spectrum mobile radio are summarized, and the areas requiring further investigation before a commercial system can be implemented are identified.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
