On Detection Issues in the SC-Based Uplink of a MU-MIMO System with a Large Number of BS Antennas

Abstract

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.

Detection issues with many BS antennas available for bandwidth-efficient uplink transmission in a MU-MIMO system

“…In this context, either a linear detection or a reduced-complexity iterative DF detection are considered, as presented in sec. II: as to the linear detection alternative, we include the optimum, Minimum Mean-Squared Error (MMSE) detection [7], a reduced-complexity MMSEtype detection [8] and the quite simple Matched Filter (MF) detection; the iterative DF detection alternative, which resorts to joint cancellation of estimated MUI/MSI, is an extension of the iterative DF technique considered by the authors, for 4-QAM transmission, in [9], and can also be regarded as an extension to the multi-input context of reduced-complexity iterative receiver techniques proposed by the authors for SIMO systems (see [10] and the references therein). This paper is an extended version of [11].…”

On the Performance of LDPC-Coded Large Intelligent Antenna System

“…Comparing these not-equalized receivers with iterative receivers that include equalization (in this case, we took into account the repetitive receivers in four iterations), the results are the same, as equalization does not bring any added value when the number of antennas is sufficiently high, which is the generic case of the LIS system. It is worth noting that the other receivers do not compute the channel matrix inverse for each frequency component, whereas the ZF does [25]. This makes the ZF significantly more computationally intensive.…”

On quasi‐optimum iterative DF detection for large‐scale MU‐MIMO systems

“…As to the linear detection alternative, besides including the optimum minimum mean‐squared error (MMSE) detection,() for the sake of comparison, we consider the quite simple matched‐filter (MF) detection and a reduced‐complexity MMSE‐type detection, both avoiding complex matrix inversions. The iterative DF detection alternative, which resorts to the joint cancellation of estimated MUI/MSI, and the estimated intersymbol interference (ISI), since we are dealing with SC/FDE, not OFDM, is an extension of the iterative DF detection technique proposed by (and evaluated for 4‐QAM transmission) Torres et al; it can also be regarded as an extension to the multi‐input context of reduced‐complexity iterative receiver techniques proposed by the authors for single‐input–multi‐output (SIMO) systems (see the works of Gusmao et al() and the references therein), although restricted here to full‐CP block transmission conditions.…”