Title :
Multi-carrier spread spectrum modulation with reduced dynamic range
Author :
Aue, Volker ; Fettweis, Gerhard P.
Author_Institution :
Mobile Commun. Syst., Tech. Univ. Dresden, Germany
Abstract :
Multi-carrier (MC) modulation has been proposed for code-division multiple access (CDMA) mobile radio communications, by modulating an identical symbol on multiple carriers of same magnitude. Certain phase offsets assigned to each carrier define a code that is given to a specific user. We introduce a CDMA system based on multi-carrier spread spectrum (MC-SS) with one identical code for all users. In general, the employment of a multi-carrier transmission technique would increase the dynamic range of the correspondent lowpass time signal, and therefore would require a highly linear power amplifier. It is shown that by carefully designing the code of a MC-SS signal a significant decrease of several orders of magnitude in the dynamic range can be obtained. The dynamic range of the resulting multi-carrier signal is of the same range as of conventional direct-sequence spread-spectrum (DS-SS) signals using OQPSK combined with raised-cosine filtering. We therefore show that MCSS CDMA is an alternative to existing DS-SS techniques proposed for mobile cellular radio and PCS, and should be considered for future mobile applications
Keywords :
cellular radio; code division multiple access; modulation; personal communication networks; spread spectrum communication; CDMA system; DS-SS signals; OQPSK; PCS; code-division multiple access; direct sequence spread spectrum; dynamic range reduction; linear power amplifier; lowpass time signal; mobile cellular radio; mobile radio communications; multicarrier spread spectrum modulation; multicarrier transmission technique; phase offsets; raised-cosine filtering; Dynamic range; Employment; Filtering; High power amplifiers; Land mobile radio; Mobile communication; Modulation coding; Multiaccess communication; Signal design; Spread spectrum communication;
Conference_Titel :
Vehicular Technology Conference, 1996. Mobile Technology for the Human Race., IEEE 46th
Conference_Location :
Atlanta, GA
Print_ISBN :
0-7803-3157-5
DOI :
10.1109/VETEC.1996.501444