Title :
Multi-rate schemes in DS/CDMA systems
Author :
Ottosson, Tony ; Svensson, Arne
Author_Institution :
Dept. of Inf. Theory, Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
Different modulation schemes supporting multiple data rates in a direct sequence code division multiple access (DS/CDMA) system are studied, focusing on how to support personal communication services. Both AWGN and multipath Rayleigh fading channels are considered. It is shown that the multi processing-gain scheme and the multi-channel scheme have almost the same performance. However, the multi-channel scheme has some advantages due to near-far resistance, easier code design and easier multi-user receiver construction. The drawback though, is the need for linear amplifiers. A multi-modulation scheme is also possible, but the performance for the users with the high data rates is significantly worse than for the other schemes
Keywords :
Gaussian channels; Rayleigh channels; code division multiple access; fading; modulation; personal communication networks; pseudonoise codes; spread spectrum communication; AWGN channels; DS/CDMA systems; code design; direct sequence code division multiple access; high data rates; linear amplifiers; modulation schemes; multichannel scheme; multimodulation scheme; multipath Rayleigh fading channels; multiprocessing gain; multirate schemes; multiuser receiver construction; near far resistance; performance; personal communication services; AWGN; Additive white noise; Amplitude modulation; Bit rate; Multiaccess communication; Personal communication networks; Pulse modulation; Pulse shaping methods; Shape; Speech;
Conference_Titel :
Vehicular Technology Conference, 1995 IEEE 45th
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-2742-X
DOI :
10.1109/VETEC.1995.505019
