Abstract-This paper deals with Single Carrier (SC)/Frequency Domain Equalization (FDE) within a MultiUser (MU)-Multi-Input Multi-Output (MIMO) system where a large number of Base Station (BS) antennas is adopted. In this context, either linear or reduced-complexity iterative Decision-Feedback (DF) detection techniques are considered. Regarding performance evaluation by simulation, appropriate semi-analytical methods are proposed.This paper includes a detailed evaluation of Bit Error Rate (BER) performances for uncoded 4-Quadrature Amplitude Modulation (4-QAM) schemes and a MU-MIMO channel with uncorrelated Rayleigh fading. The accuracy of performance results obtained through the semi-analytical simulation methods is assessed by means of parallel conventional Monte Carlo simulations, under the assumptions of perfect power control and perfect channel estimation. The performance results are discussed in detail, with the help of selected performance bounds. We emphasize that a moderately large number of BS antennas is enough to closely approximate the Single-Input Multi-Output (SIMO) Matched-Filter Bound (MFB) performance, especially when using the suggested low-complexity iterative DF technique, which does not require matrix inversion operations. We also emphasize the achievable "massive MIMO" effects, even for strongly reduced-complexity linear detection techniques, provided that the number of BS antennas is much higher than the number of antennas which are jointly employed in the terminals of the multiple autonomous users.
This paper deals with Cyclic Prefix (CP)-assisted block transmission solutions for future mobile broadband systems, in the context of a Single Carrier (SC)-Frequency Division Multiple Access (FDMA) uplink. Two alternative choices are considered regarding the subcarrier mapping rule: a "localized" subcarrier mapping where user's data occupy a set of consecutive subcarriers (Rule R1); a "distributed" subcarrier mapping where user's data occupy a set of uniformly spaced subcarriers (Rule R2).Detailed performance evaluations, in this paper, involve the consideration of two iterative FDE receiver techniques, with different complexity levels, which can be regarded as extensions of iterative receiver techniques proposed previously within a single user context. A selected class of multipath radio channels, providing a range of channel time dispersion levels, is assumed for performance evaluation purposes, and a set of matched filter bounds on receiver performance plays a relevant role in "achievable performance" comparisons. Both the impact of the mapping rules and that of the iterative receiver techniques considered here are evaluated in detail. This paper also studies the performance degradation due to a channel impulse response longer than the CP: such degradation is related to an "ICI (InterChannel Interference) effect" (possibly involving a multi-user interference component) which is inherent to the insufficient-CP conditions. The performance advantages under rule R2 are emphasized for a low or moderate channel time dispersion, and both specific iterative receiver techniques; for a higher time dispersion, receiver performances become very similar with both rules, at the BER values of practical interest (say, BER=10 −5 ). Having in mind that rule R2 has a power efficiency advantage regarding transmitter implementation (due to the reduced envelope fluctuations), we can conclude that this rule provides a clear overall power efficiency advantage, regarding both transmitter and receiver issues, for the entire range of channel time dispersion levels.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.