A time diversity CDMA scheme employing orthogonal modulation for time varying channels

Author

Kubota, Shuji ; Kato, Shuzo ; Feher, Kamilo

Author_Institution

NTT Radio Commun. Syst. Lab., Yokosuka, Japan

fYear

1993

fDate

18-20 May 1993

Firstpage

444

Lastpage

447

Abstract

In order to increase the channel capacity of CDMA (code division multiple access) mobile and personal communication systems, a new time diversity CDMA scheme that employs orthogonal modulation is proposed. The time diversity CDMA scheme with orthogonal modulation reduces the required Eb/(No+Io) by 5 dB at Pe = 10^-2 in Rayleigh fading environments with fDT (the product of Doppler frequency and one symbol duration) values ranging from 0.002 to 0.02. This improvement in required Eb/(No+Io) significantly increases the channel capacity of CDMA communication systems that have time varying channels. Computer simulation results show that the required time delay values of the time diversity scheme are resonably short (20-100 symbols for 10 kbps transmission) for fDT values ranging from 0.002 to 0.02

Keywords

Rayleigh channels; channel capacity; code division multiple access; delays; diversity reception; fading; land mobile radio; personal communication networks; simulation; time-varying channels; 10 kbit/s; Rayleigh fading; channel capacity; mobile communication systems; orthogonal modulation; personal communication systems; time delay; time diversity CDMA scheme; time varying channels; AWGN; Binary phase shift keying; Channel capacity; Digital modulation; Laboratories; Modulation coding; Multiaccess communication; Phase modulation; Quadrature phase shift keying; Time varying systems;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1993., 43rd IEEE

Conference_Location

Secaucus, NJ

ISSN

1090-3038

Print_ISBN

0-7803-1267-8

Type

conf

DOI

10.1109/VETEC.1993.507507

Filename

507507