Burst-by-Burst Adaptive Multiuser Detection CDMA: A Framework for Existing and Future Wireless Standards

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Description/Abstract

This paper provides a broad overview of the multiuser detection literature of the past few years in a nonmathematical, easily accessible approach. The treatment is then extended to the comparative study of channel-quality controlled burst-by-burst (BbB) adaptive code division multiple access (CDMA) detection such as parallel interference cancellation, successive interference cancellation, and joint detection (JD). It is demonstrated that the best complexity versus performance tradeoff is constituted by the JD receivers. Furthermore, the BbB-adaptive variable spreading factor-based schemes considered were outperformed by the adaptive quadrature amplitude modulation-based JD-CDMA schemes investigated. For example, at a channel signal-to-noise ratio per bit value of $E_b=N_0$ = 14 dB the latter scheme provides an average bit per symbol (BPS) throughput of 3.39, while the former provides an average BPS throughput of only 2.83, although the complexity of the latter is lower. In conclusion, BbB-adaptive CDMA schemes provide an attractive performance versus complexity tradeoff and are amenable to employment in both existing and future generations of wireless systems. Keywords—Adaptive CMDA systems, adaptive transceivers, interference cancellation, multiuser detection.