Abstract
Multicarrier CDMA (MC-CDMA) has become a promising candidate for future wireless multimedia communications for its robustness to frequency-selective fading and its flexibility in handling multiple data rates. Among different multirate access schemes, multicode MC-CDMA is attractive for its high performance, good flexibility in rate matching, and low complexity. However, its performance is limited by self-interference (SI) and multiuser interference (MUI). In this paper, a zero-forcing successive interference cancellation (ZF-SIC) receiver is used to mitigate this problem for multicode MC-CDMA. Furthermore, optimal power distribution control (PDC), which minimizes each user's bit error rate (BER), is considered. Our results show that, in correlated Rayleigh fading channels, the ZF-SIC receiver integrated with the optimal PDC dramatically improves the performance of the multicode MC-CDMA system in comparison with other receivers proposed in the literature. Moreover, the optimal PDC significantly outperforms the PDC based on equal BER criterion, particularly under a short-term transmit power constraint.
Highlights
Multicarrier CDMA (MC-CDMA) combines multicarrier modulation (MCM) and DS-CDMA, and is characterized by its robustness to channel frequency selectivity and its simple receiver structure [1, 2, 3, 4]
Besides showing the performance of the zero-forcing successive interference cancellation (SIC) (ZF-SIC) receiver integrated with the optimal power distribution control (PDC) and equal bit error rate (BER) PDC discussed in this paper, the performance of the ZF receiver without SIC and the ZF-SIC receiver without PDC are presented for comparison
A nonlinear ZF-SIC receiver was applied for multicode MCCDMA and a solution of optimal PDC was presented
Summary
Multicarrier CDMA (MC-CDMA) combines multicarrier modulation (MCM) and DS-CDMA, and is characterized by its robustness to channel frequency selectivity and its simple receiver structure [1, 2, 3, 4]. A zero-forcing SIC (ZF-SIC) receiver is applied to multicode MC-CDMA, by which parallel symbols transmitted on different spreading codes are detected successively and, for each symbol (of the same or different users), a ZF receiver (decorrelator) is employed to eliminate interference. We investigate a PDC algorithm suitable for the nonlinear ZF-SIC receiver in a multicode MC-CDMA system For such a system, PDC becomes more important than for a single-rate system, since without PDC it is customary to let the transmit power of each user be evenly distributed among all its spreading codes, which reduces the efficiency of SIC.
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