EQSM-based multiuser MIMO downlink transmission for correlated fading channels (original) (raw)
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Quadrature spatial modulation basedmultiuser MIMO transmission system
IET Communications
This study presents a multiuser (MU) multiple-input multiple-output (MIMO) downlink transmission scheme based on the quadrature spatial modulation (QSM) concept, which uses the indices of the non-zero entries in its transmission vector to modulate and transmit an independent sequence of bits for each user in the system. The MU interference is removed by using a matrix precoding technique based on channel state information (CSI) known as block diagonalisation (BD). The performance of the proposed scheme is compared with the conventional MU-MIMO-BD system for uncorrelated Rayleigh fading channels and correlated fading channels with imperfect CSI in the reception. Additionally, a low-complexity near maximum likelihood (ML) detection algorithm for the MU-MIMO-QSM signal's detection is proposed. For the considered cases, the proposed MU-MIMO-QSM scheme exhibits gains up to 1 dB in bit error rate performance and a reduction in detection complexity up to 93% as compared to the conventional MU-MIMO-BD scheme for the optimal ML detection. The proposed algorithm performs very near to the optimal ML detector whilst achieving a complexity reduction of up to 58%.
This paper presents a novel scheme to transmit signals in a Multiuser Multiple-Input Multiple-Output (MU-MIMO) downlink scenario. The proposed scheme combines Block Diagonalization (BD) and Generalized Spatial Modulation (SM) Techniques. The SM technique is used to add a broadcast transmission to the conventional MU-MIMO BD scheme, which results in a novel BDSM proposal. We compare the proposed BDSM scheme with the conventional BD scheme considering the Bit Error Rate (BER) performance , detection complexity, and spectral efficiency using Maximum Likelihood (ML) joint-detection and ML segmented-detection algorithms. A correlated fading channel with Rayleigh distribution is considered. Simulations results show that the broadcast transmission can be added to the BD scheme without performance impairment. The proposed BDSM system has performance gains of 4 dB for error rates of 10 À3 approximately when some bits are considered as broadcast transmission in the BD scheme. In general , the proposed detection algorithms have a tradeoff between the BER performance and the detector's complexity.
Extended quadrature spatial modulation for MIMO wireless communications
Physical Communication, 2018
This paper presents an extended quadrature spatial modulation (EQSM) scheme that combines K quadrature spatial modulation (QSM) constellations to achieve a K-fold spectral efficiency (SE) enhancement. The idea underlying EQSM consists in using the average powers of the K QSM constellations as an additional dimension for the transmission of information bits. The modulation process starts with the design of a conventional QSM constellation. The remaining (K −1) QSM constellations are then configured with scaled amplitudes considering the same group of transmit antennas. The EQSM constellation is obtained by the superposition of the K scaled QSM constellations. A novel near maximum likelihood (ML) low-complexity algorithm for EQSM signal detection is also proposed in this paper. Analytical and simulation results obtained for independent and identically distributed (i.i.d.) Rayleigh fading channels show that the proposed EQSM scheme provides gains of up to 2.5, 5, 7, and 8 dB in bit error rate (BER) performance as compared to spatial multiplexing (SMux), double spatial modulation (DSM), conventional QSM, and spatial modulation (SM), respectively. In terms of detection complexity, EQSM allows a 67% complexity reduction when compared to SMux, and a 20% increase as compared to SM/QSM schemes. The obtained results also show that the proposed near ML detection algorithm reduces the complexity of the ML criterion by 82%, while achieving near optimal ML performance.
Multiuser MIMO downlink transmission using spatial modulation
2014 IEEE Latin-America Conference on Communications (LATINCOM), 2014
This paper presents a novel scheme to transmit signals in a downlink Multiuser Multiple-Input Multiple-Output (MU-MIMO) scenario. The proposed scheme uses the recently introduced Spatial Modulation (SM) technique to transmit a broadcast signal for multiple users. It has the advantage of not requiring Channel State Information (CSI) at the transmitter side, while simultaneously it offers flexibility for transmitting different quantity of bits per user. Analytical and Monte Carlo Simulations results are reported. For the analyzed cases, the proposed scheme has performance gain of 10 dB for an Average Bit Error Probability (ABEP) of approximately 10 -3 , when compared to the conventional channel inversion scheme based on precoding with knowledge of the CSI.
Precoding for RIS-Assisted Multi-User MIMO-DQSM Transmission Systems
Future Internet
This paper presents two precoding techniques for a reconfigurable intelligent surface (RIS)-assisted multi-user (MU) multiple-input multiple-output (MIMO) double quadrature spatial modulation (DQSM) downlink transmission system. Instead of being applied at the remote RIS, the phase shift vector is applied at the base station (BS) by using a double precoding stage. Results show that the proposed RIS-MU-MIMO-DQSM system has gains of up to 17 dB in terms of bit error rate (BER) and a reduction in detection complexity of 51% when compared with the conventional MU-MIMO system based on quadrature amplitude modulation (QAM). Compared with a similar system based on amplify and forward (AF) relay-assisted technique, the proposed system has a gain of up to 18 dB in terms of BER under the same conditions and parameters.
Redesigned Spatial Modulation for Spatially Correlated Fading Channels
In this paper, a new variant of Spatial Modulation (SM) Multiple-Input Multiple-Output (MIMO) transmission technique, designated as Redesigned Spatial Modulation (ReSM) has been proposed. In ReSM scheme, a dynamic mapping for antenna selection is adopted. This scheme employs both single antenna as well as double antenna combinations depending upon channel conditions to combat the effect of spatial correlation. When evaluated over spatially correlated channel conditions, for a fixed spectral efficiency and number of transmit antennas, ReSM exhibits performance improvement of at least 3 dB over all the conventional SM schemes including Trellis Coded Spatial Modulation (TCSM) scheme. Furthermore, a closed form expression for the upper bound on Pairwise Error Probability (PEP) for ReSM has been derived. This has been used to calculate the upper bound for the Average Bit Error Probability (ABEP) for spatially correlated channels. The results of Monte Carlo simulations are in good agreement with the predictions made by analytical results. The relative gains of all the comparison plots in the paper are specified at an ABER of 10-4 .
Exploiting Spatial and Frequency Diversity in Spatially Correlated MU-MIMO Downlink Channels
Journal of Computer Networks and Communications, 2012
The effect of self-interference due to the increase of spatial correlation in a MIMO channel has become one of the limiting factors towards the implementation of future network downlink transmissions. This paper aims to reduce the effect of self-interference in a downlink multiuser-(MU-) MIMO transmission by exploiting the available spatial and frequency diversity. The subcarrier allocation scheme can exploit the frequency diversity to determine the self-interference from the ESINR metric, while the spatial diversity can be exploited by introducing the partial feedback scheme, which offers knowledge of the channel condition to the base station and further reduces the effect before the allocation process takes place. The results have shown that the proposed downlink transmission scheme offers robust bit error rate (BER) performance, even when simulated in a fully correlated channel, without imposing higher feedback requirements on the base controller.
Quadrature spatial modulation-performance analysis and impact of imperfect channel knowledge
Transactions on Emerging Telecommunications Technologies, 2014
Abstract-Quadrature Spatial Modulation (QSM) is a recently proposed Multiple-Input Multiple-Output (MIMO) transmission technique. In QSM, location dependent spatial information utilized to carry additional bits is expanded to include quadrature dimension in addition to the conventional SM real dimension. As such, an increase of the overall transmission data rate with base two logarithm of the square of the number of existing transmit antennas is achieved. In this paper, first, QSM performance over Rician fading channel is investigated, second, analytical framework supported by Monte Carlo simulation is established, and third, detailed results highlighting the impact of LOS on QSM performance are presented. Obtained analytical and simulation results show that QSM outperforms SM over Rician fading channels.
Performance Evaluation of Spatial Modulation and QOSTBC for MIMO Systems
ICST Transactions on Mobile Communications and Applications, 2015
Multiple-input multiple-output (MIMO) systems require simplified architectures that can maximize design parameters without sacrificing system performance. Such architectures may be used in a transmitter or a receiver. The most recent example with possible low cost architecture in the transmitter is spatial modulation (SM). In this study, we evaluate the SM and quasi-orthogonal space time block codes (QOSTBC) schemes for MIMO systems over a Rayleigh fading channel. QOSTBC enables STBC to be used in a four antenna design, for example. Standard QO-STBC techniques are limited in performance due to self-interference terms; here a QOSTBC scheme that eliminates these terms in its decoding matrix is explored. In addition, while most QOSTBC studies mainly explore performance improvements with different code structures, here we have implemented receiver diversity using maximal ratio combining (MRC). Results show that QOSTBC delivers better performance, at spectral efficiency comparable with SM.
Orthogonal space-time block coding with adaptive transmit diversity for correlated MIMO channels
In this paper we introduce a technique of eigenbeamforming based on the channel correlation matrix and paired with orthogonal space-time code (O-STBC) at the transmitter side of the link. This structure combines the spatial signal paths decorrelation with the diversity gain provided by the space-time code, which results in performance improvement. The probability distributions for both bit-error-rate (BER) and symbolerror-rate (SER) are presented based on the received signal-to-noise ratio (SNR) for this system. The system has been simulated using four transmit antennas in both uncorrelated and correlated channels. Results showed that the proposed scheme provides a significant improvement in the error rate performance of spatially correlated channels.