The cross-correlation function and the side-lobes of the auto-correlation function of LS codes are zero in a certain vicinity of the zero shift. Therefore, the effects of the Inter-Symbol-interference and multiple-Acc...
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ISBN:
(纸本)9781424407545
The cross-correlation function and the side-lobes of the auto-correlation function of LS codes are zero in a certain vicinity of the zero shift. Therefore, the effects of the Inter-Symbol-interference and multiple-access-interference that appears in CDMA and multi-sensor systems are mitigated. Conventionally, the detection of these sequences has been achieved by means of straight-forward matched-filter correlators. In this paper, a new correlator which significantly reduces the total number of operations to be performed is proposed, allowing real-time operation.
作者：
Huang, KBAdachi, FChew, YHUniv Texas
Dept Elect & Comp Engn Austin TX 78712 USA Tohoku Univ
Dept Elect & Commun Engn Grad Sch Engn Sendai Miyagi 9808579 Japan ASTAR
Inst Infocomm Res Singapore 119613 Singapore
In this paper, we improve the performance analysis of the Rake receiver for the DS-CDMA forward link using long random spreading sequences (RSS's) [15] by more accurately evaluating the correlation between the var...
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In this paper, we improve the performance analysis of the Rake receiver for the DS-CDMA forward link using long random spreading sequences (RSS's) [15] by more accurately evaluating the correlation between the various interference terms. We also extend the analysis to the case of short (periodic) RSS. The accuracy of the expressions obtained in our analysis is verified by computer simulation. We show that for a given normalized spreading factor, the bit error rate (BER) performance of the Rake receiver is the same for BPSK and QPSK data modulation. We also show that when the channel delay spread is smaller than a data symbol duration, the CDMA receiver has similar BER performance for long and short RSS's. However, for large delay spread, the employment of short RSS's may result in severe performance degradation.
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