DocumentCode :
379471
Title :
Increasing CDMA capacity using multiple orthogonal spreading sequence sets and successive interference cancellation
Author :
Vanhaverbeke, F. ; Moeneclaey, M. ; Sari, H.
Author_Institution :
TELIN/DIGCOM, Ghent Univ., Gent, Belgium
Volume :
3
fYear :
2002
fDate :
2002
Firstpage :
1516
Abstract :
In this paper, we present a code-division multiple access (CDMA) system with a spreading factor of N that can accommodate up to mN users, where m≥2. The m sets of orthogonal spreading sequences are constructed by overlaying the same N orthogonal Walsh-Hadamard sequences with a set-specific pseudo-noise (PN) sequence. Interference between user signals from different sets is cancelled by means of soft-decision iterative interference cancellation. We show that this technique, which is referred to as m-OCDMA, can accommodate more users and is computationally less complex than conventional PN-CDMA with the same type of interference cancellation. Assuming BPSK transmission over an additive white Gaussian noise (AWGN) channel and perfect power control, a degradation of 0.4 dB at the BER of 10-5 in m-OCDMA is obtained with 2.56N users in the uplink or 3.03N users in the downlink. In PN-CDMA, this figure is 2.16N for both the uplink and the downlink.
Keywords :
AWGN channels; code division multiple access; error statistics; interference suppression; iterative methods; pseudonoise codes; spread spectrum communication; 0.4 dB; AWGN channel; BPSK transmission; CDMA capacity; additive white Gaussian noise channel; code-division multiple access; m-OCDMA; multiple orthogonal spreading sequence sets; orthogonal Walsh-Hadamard sequences; power control; set-specific pseudo-noise sequence; soft-decision iterative interference cancellation; spreading factor; successive interference cancellation; AWGN; Additive white noise; Binary phase shift keying; Downlink; Error correction; Frequency conversion; Interference cancellation; Multiaccess communication; Noise cancellation; Time division multiple access;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Communications, 2002. ICC 2002. IEEE International Conference on
Print_ISBN :
0-7803-7400-2
Type :
conf
DOI :
10.1109/ICC.2002.997103
Filename :
997103
Link To Document :
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