In this paper, a spatial modulation aided uplink non-orthogonal multiple access (SM-NOMA) without successive interference cancellation (SIC) is proposed. The SIC-free SM-NOMA system is investigated under both perfect ...
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In this paper, a spatial modulation aided uplink non-orthogonal multiple access (SM-NOMA) without successive interference cancellation (SIC) is proposed. The SIC-free SM-NOMA system is investigated under both perfect and imperfect channel state information (CSI). Moreover, on the receiver side, both SIC-based and SIC-free detection techniques are used to analyze the bit error rate (BER) performance of SM-NOMA. Finally, the performance of SIC-free SM-NOMA is evaluated and compared with the conventional NOMA, and SIC-based SM-NOMA. The results show that the SIC-free SM-NOMA outperforms conventional NOMA in terms of spectral efficiency, energy efficiency, and BER.(c) 2021 The Author(s). Published by Elsevier B.V. on behalf of The Korean Institute of Communications and Information Sciences. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).
This letter presents a sphere decoding strategy for generalized spatial modulation (GSM) systems. The proposed modifications reduce the exhaustive tree search for lattice points and exploits the structure of GSM, rest...
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This letter presents a sphere decoding strategy for generalized spatial modulation (GSM) systems. The proposed modifications reduce the exhaustive tree search for lattice points and exploits the structure of GSM, restraining the tree branches to those that result in valid antenna combinations. As a result, every found lattice point results in valid GSM transmitted symbols. The numerical results exhibit significant complexity reduction.
This letter proposes a unified differential spatial modulation (DSM) architecture, where a flexible rate-diversity tradeoff is achieved, while enabling a simple single-RF transmitter structure along with non-coherent ...
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This letter proposes a unified differential spatial modulation (DSM) architecture, where a flexible rate-diversity tradeoff is achieved, while enabling a simple single-RF transmitter structure along with non-coherent detection that dispenses with channel estimation at the receiver. In our proposed scheme, by assigning a set of sparse complex-valued antenna-index matrices, only one transmit antenna element is activated during each symbol interval and then a phase-shift keying (PSK) symbol is transmitted from the activated antenna element. The explicit benefit of the proposed scheme's universal DSM framework is ability to strike a balance between previous DSM schemes, such as the symbol-based and the block-based DSM schemes. Moreover, to attain a useful attainable diversity gain, we further extend the proposed DSM scheme in a manner that permits flexible planning of the number of symbols employed per antenna-index block.
spatial modulation (SM) conveys additional information bits via the index of an activated transmit antenna. When the number of antennas is not an integer power of two, the antenna activation becomes challenging. In su...
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spatial modulation (SM) conveys additional information bits via the index of an activated transmit antenna. When the number of antennas is not an integer power of two, the antenna activation becomes challenging. In such a case, only a subset of the available transmit antennas whose cardinality is an integer power of two is used. This leads to antenna activation with unequal probability, which causes high error rates and losses in the spectral efficiency. The same limitations and performance losses equally exist in quadrature spatial modulation (QSM) and generalized spatial modulation (GSM), the two prominent variants of SM. In this contribution, in contrast to the conventional approach of antenna activation within each symbol period, a space-time bit-mapping method in which the antenna selection procedure is extended to multiple symbol periods is proposed. Use of the proposed method in SM, QSM, and GSM techniques, is shown to achieve performances close to their full potential for any given number of transmit antennas, with only a marginal increment in detection complexity.
This letter proposes two contributions to improve the performance of transmission with generalized multistream spatial modulation (SM). In particular, a modified suboptimal detection algorithm based on the Gaussian ap...
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This letter proposes two contributions to improve the performance of transmission with generalized multistream spatial modulation (SM). In particular, a modified suboptimal detection algorithm based on the Gaussian approximation method is proposed. The proposed modifications reduce the complexity of the Gaussian approximation method and improve the performance for high signal-to-noise ratios. Furthermore, this letter introduces signal constellations based on Hurwitz integers, i.e., a 4-D lattice. Simulation results demonstrate that these signal constellations are beneficial for generalized SM with two active antennas.
Novel transmit antenna selection techniques are conceived for spatial modulation (SM) systems and their symbol error rate (SER) performance is investigated. Specifically, low-complexity Euclidean Distance optimized An...
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Novel transmit antenna selection techniques are conceived for spatial modulation (SM) systems and their symbol error rate (SER) performance is investigated. Specifically, low-complexity Euclidean Distance optimized Antenna Selection (EDAS) and Capacity Optimized Antenna Selection (COAS) are studied. It is observed that the COAS scheme gives a better SER performance than the EDAS scheme. We show that the proposed antenna selection based SM systems are capable of attaining a significant gain in signal-to-noise ratio (SNR) compared to conventional SM systems, and also outperform the conventional MIMO systems employing antenna selection at both low and medium SNRs.
In this letter, a linear precoding scheme is proposed for downlink (DL) multi-user (MU) generalized spatial modulation (GSM) systems. The proposed precoding scheme achieves, not only inter-user interference (IUI) free...
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In this letter, a linear precoding scheme is proposed for downlink (DL) multi-user (MU) generalized spatial modulation (GSM) systems. The proposed precoding scheme achieves, not only inter-user interference (IUI) free, but also maximum signal-to-noise ratio (SNR). The former achievement leads to higher multiplexing gain, while the later results in higher diversity gain. By formulating the precoder design as a constrained optimization problem, the optimal precoding vectors are derived by using singular value decomposition (SVD). Outage and ergodic capacities of the proposed scheme are then analyzed, and compared to that of the conventional GSM scheme and the MU zero-forcing (ZF) transmit beamforming scheme by simulations. Simulation results indicate that the proposed scheme can effectively eliminate the IUI, and achieve significant diversity gain.
We consider a spatial modulation aided indoor visible light communication system with user mobility and random receiver orientation. Two artificial neural networks (ANNs) are proposed which are able to predict the cha...
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We consider a spatial modulation aided indoor visible light communication system with user mobility and random receiver orientation. Two artificial neural networks (ANNs) are proposed which are able to predict the channel state information (CSI) with high accuracy and resolution. These architectures use estimated CSI at pilot instances obtained using least square or minimum mean square error estimation and predict CSI at intermediate locations. Moreover in ANN 2, predicted user position information is used to improve the performance. Numerical results show that the proposed ANNs deliver a better bit error rate compared to a benchmark spline interpolation-based method. Further, ANN 2 is shown to perform robustly in a high mobility scenario.
In this letter, a precoded spatial modulation-aided cooperative nonorthogonal multiple access (NOMA), referred to as PC-NOMA, has been proposed for multiple-input and multiple-output (MIMO) downlink scenario. In PC-NO...
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In this letter, a precoded spatial modulation-aided cooperative nonorthogonal multiple access (NOMA), referred to as PC-NOMA, has been proposed for multiple-input and multiple-output (MIMO) downlink scenario. In PC-NOMA scheme, the base station (BS) broadcasts three users' information over two time slots: in the first slot, the two near users receive data through direct links and in the second slot, the third user (far) receives data indirectly from the near users. The precoded direct links' signal has been superposed with indirect link's signal in broadcast phase at the BS. The indirect link's signal has been decoded and forwarded at the direct link's user using the successive-interference cancellation (SIC) method in cooperative phase. The symbol error rate (SER) and mutual information (MI) under inter-users interference (IUI) have been derived for the proposed PC-NOMA. The impact of various system parameters, such as the number of transmitting and receiving antennas, have been analyzed for the proposed PC-NOMA.
One of the techniques that helps to reduce the error probability for communication systems is transmit antenna selection (TAS). TAS with maximizing the minimum Euclidean distance, called Euclidean Distance Antenna Sel...
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One of the techniques that helps to reduce the error probability for communication systems is transmit antenna selection (TAS). TAS with maximizing the minimum Euclidean distance, called Euclidean Distance Antenna Selection (EDAS), achieves high transmit diversity for spatial modulation (SM) systems. This letter focuses on a novel, very simple and low complexity antenna selection algorithm for EDAS. The main idea of this work is based on using eigenvectors obtained from the eigendecomposition of the matrix composed from the transmit SM signal difference vector. However, due to the characteristics of the SM, only certain eigenvectors are sufficient to achieve the Euclidean distance instead of all possible combinations of transmitted symbols. In addition, an algorithm is given in this study to find the required eigenvectors without the need for eigendecomposition. Simulation results show that our proposed method exhibits same symbol error rate performance as conventional optimum EDAS, but having lower complexity.
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