Title :
M-ary MC-CDMA using quadrature spreading codes for wireless communications system
Author :
Zhou, Wuyang ; Xia, Pengfei ; Zhu, Jinkang
Author_Institution :
PCN&SS Lab., Univ. of Sci. & Technol. of China, Hefei, China
Abstract :
We present a new modulation method, i.e., M-ary MC-CDMA system with quadrature spreading codes. In the transmitter, M-ary orthogonal modulation is applied to serial-to-parallel converted data bits. The modulated symbol is then spread in the frequency domain using each chip of complex orthogonal codes. Each spread symbol is then modulated on corresponding subcarrier, finally the multiple branches are combined and transmitted. Considering the frequency selective slowly fading, we investigate the system´s downlink performance. Using equal gain combination (EGC) and maximum ratio combination (MRC), we study the effect of complex quadrature spreading codes on the system performance and compare it with that of the single spreading code case. Also we analyse the effect of the guard time on the system and compare it with that of no guard time
Keywords :
OFDM modulation; Rayleigh channels; code division multiple access; codes; diversity reception; land mobile radio; multiuser channels; radio links; spread spectrum communication; M-ary MC-CDMA; M-ary orthogonal modulation; OFDM; Rayleigh channel; downlink performance; equal gain combination; frequency domain; frequency selective slowly fading; guard time; maximum ratio combination; mobile radio; modulated symbol spreading; multicarrier modulation; orthogonal codes; quadrature spreading codes; serial-to-parallel converted data bits; single spreading code; subcarrier; transmitter; wireless communications system; Downlink; Fading; Frequency domain analysis; Interference; Modulation coding; Multicarrier code division multiple access; OFDM modulation; Performance gain; Transmitters; Wireless communication;
Conference_Titel :
Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5718-3
DOI :
10.1109/VETECS.2000.851456
