Title :
Nonlinear effect of direct-sequence CDMA in optical transmission
Author :
Huang, Wei ; Nakagawa, Masao
Author_Institution :
Dept. of Electr. Eng., Keio Univ., Yokohama, Japan
fDate :
28 Nov- 2 Dec 1994
Abstract :
The intermodulation distortion (IMD) due to laser diode (LD) nonlinearity of an asynchronous direct-sequence code division multiple access (DS/CDMA) system in optical transmission is analyzed. A third-order polynomial without memory is used to present LD nonlinearity. In DS/CDMA systems, only one harmonic of the third-order intermodulation term falls on the signal frequency band and influences the system performance. The average distortion is derived with only the information of auto-correlation functions. The results are useful for CDMA system design and performance analysis. With LD nonlinearity it is necessary to select an optimal modulation index that provides a maximum signal-to-noise ratio (SNR). The LD nonlinearity on CDMA and frequency-division multiple access (FDMA) is also compared. The analytical method is applicable to other general nonlinearities in CDMA systems
Keywords :
cellular radio; code division multiple access; correlation methods; intermodulation distortion; pseudonoise codes; spread spectrum communication; CDMA system design; CDMA system performance analysis; FDMA; SNR; asynchronous direct-sequence CDMA; auto-correlation function; average distortion; cellular radio; direct-sequence code division multiple access; frequency-division multiple access; intermodulation distortion; laser diode nonlinearity; maximum signal-to-noise ratio; optical transmission; optimal modulation index; signal frequency band; system performance; third-order intermodulation; third-order polynomial; Autocorrelation; Diode lasers; Frequency; Intermodulation distortion; Multiaccess communication; Nonlinear optics; Optical distortion; Polynomials; System analysis and design; System performance;
Conference_Titel :
Global Telecommunications Conference, 1994. GLOBECOM '94. Communications: The Global Bridge., IEEE
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-1820-X
DOI :
10.1109/GLOCOM.1994.512845
