DocumentCode :
295253
Title :
On the deorthogonalization of ODS-CDMA 4-PSK in frequency-nonselective shadowed Rician fading
Author :
Pawlowski, Peter R.
Author_Institution :
Space & Electron. Group, TRW Inc., Redondo Beach, CA, USA
Volume :
2
fYear :
1995
fDate :
27-29 Sep 1995
Firstpage :
424
Abstract :
Using a conventional demodulator, a sufficient condition to maintain orthogonal direct sequence-code-division multiple access (ODS-CDMA) codeword orthogonality is constant relative channel amplitude over the codeword duration. Fading produces a fluctuating amplitude that deorthogonalizes the codewords, resulting in an additional noise similar to the multiaccess interference (MAI) found in asynchronous DS-CDMA. For ODS-CDMA 4-PSK in a frequency-nonselective, shadowed Rician fading channel, we derive and evaluate: (i) an exact expression for the uncoded bit error probability, and (ii) an upper bound for the convolutionally-coded bit error probability. We find that the degradation to BER depends on both the fading parameters and the ODS-CDMA channel loading
Keywords :
Rician channels; code division multiple access; coding errors; convolutional codes; demodulation; demodulators; error statistics; fading; phase shift keying; probability; pseudonoise codes; spread spectrum communication; BER; ODS-CDMA 4-PSK; ODS-CDMA channel loading; ODS-CDMA codeword orthogonality; codeword duration; constant relative channel amplitude; convolutionally-coded bit error probability; demodulator; deorthogonalization; exact expression; fading parameters; frequency-nonselective shadowed Rician fading; sufficient condition; uncoded bit error probability; upper bound; Demodulation; Error probability; Fading; Frequency division multiaccess; Multiaccess communication; Multiple access interference; Noise level; Quadrature phase shift keying; Rician channels; Sufficient conditions;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 1995. PIMRC'95. Wireless: Merging onto the Information Superhighway., Sixth IEEE International Symposium on
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-3002-1
Type :
conf
DOI :
10.1109/PIMRC.1995.480904
Filename :
480904
Link To Document :
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