Spatial modulation (SM) is an innovative and promising digital modulation technology that strikes an appealing tradeoff between spectral efficiency and energy efficiency with a simple design philosophy. SM enjoys plenty of benefits and shows great potential to fulfill the requirements of future wireless communications. The key idea behind SM is to convey additional information typically through the ON/OFF states of transmit antennas and simultaneously save the implementation cost by reducing the number of radio-frequency chains. As a result, the SM concept can have widespread effects on diverse applications and can be applied in other signal domains, such as frequency/time/code/angle domain or even across multiple domains. This survey provides a comprehensive overview of the latest results and progresses in SM research. Specifically, the fundamental principles, variants of system design, and enhancements of SM are described in detail. Furthermore, the integration of the SM family with other promising techniques, applications to emerging communication systems, and extensions to new signal domains are also extensively studied.

A Survey on Spatial Modulation in Emerging Wireless Systems: Research Progresses and Applications

In this paper, we investigate the benefits of power allocation (PA) for multiple-input multiple-output (MIMO) receive spatial modulation (RSM) with both a total transmit power constraint (TTPC) and a per-antenna power constraint (PAPC). First, we derive optimal PA closed-form solutions that maximize the minimum distance $d_{\text{min}}$ between the received signal points for $(N_t\times 2)$ -element RSM with arbitrary phase-shift keying schemes (where $N_t$ is the number of transmit antennas) subject to a TTPC. Based on the derived solutions and the error vector reduction (EVR) method, we propose a low-complexity iterative algorithm to identify PA parameters for high numbers of receive antennas ( $N_r\geq 2$ ). Specifically, the EVR-based PA (EVR-PA) algorithm resembles its traditional exhaustive-search-based counterpart, but only exploits the receive distances of a few dominant error vectors to iteratively optimize the PA matrix. Then, a more strict yet practical PAPC is considered for PA in RSM-MIMO systems, and a well-designed approximate convex optimization (ACO)-based iterative PA algorithm is proposed. Compared to EVR-PA, the ACO-based PA (ACO-PA) algorithm first formulates the PA problems with the PAPC in RSM into constrained quadratic program problems and then utilizes the powerful augmented Lagrangian multiplier to find their optimal solutions. Our simulation results show that the proposed EVR-PA- and ACO-PA-aided RSM schemes outperform the equal-power-allocated RSM- and PA-aided spatial multiplexing schemes.

Enhanced Receive Spatial Modulation Based on Power Allocation

Recently, a receive spatial modulation (RSM) for massive multiple-input-multiple-output operating in millimeter wave (mmWave) was introduced with the purpose of simplifying user terminal circuit by employing only one radio-frequency chain and attaining high spectral efficiency by exploiting the receive spatial dimension. However, when RSM is applied in a mmWave channel, it demands a challenging receive antenna selection (RAS) procedure. On the other hand, the power consumption at the transmitter side is high when a full digital (FD) precoder is envisioned. We consider the joint problem of RAS and precoder designs based low complexity hybrid architecture. For the sake of simplicity, we divide this problem into two subproblems. First, we design the RAS assuming FD precoder, and then, we design the hybrid precoder. We propose two novel and efficient RAS methods. First, we formulate the RAS as non-convex optimization problem. Then, we convert it into a convex optimization problem by introducing novel lower bounds and relaxing non-convex constraints. Second, we provide sequential algorithms that approach the optimal selection where we (add/remove) one (good/poor) antenna per iteration. We propose novel zero forcing hybrid precoder based convex optimization that maximizes the received power. We prove that the proposed precoder is optimal when the channel is highly spatially sparse. The proposed designs have been compared with the best known methods in terms of average mutual information and energy efficiency showing significant improvements.

Receive Antenna Selection and Hybrid Precoding for Receive Spatial Modulation in Massive MIMO Systems

Massive Multiple Input Multiple Output (m-MIMO) or Large Scale Antenna System (LSAS) is the latest version of cellular network technology with the purpose to send data from the base station to different users. The huge determined expansion in the mobile equipment and data rate requirement has created the rigid necessity for future wireless communication networks. The m-MIMO envisages a significant increase in the capacity but at the verge of excessive hardware complication. In this paper, we put forward a less complex precoding scheme based on the hybrid architecture to achieve a performance higher than the conventional baseband Minimum Mean Square Estimation (MMSE) precoding. In this paper, we propose a precoding schema namely amplitude and phase MMSE (APMMSE) to attain the performance of traditional MMSE precoding. The informed greedy best-first search has offered to estimate the baseband precoding matrix. It formulates the amplitude of the baseband precoder. Radio Frequency Precoder modifies the phase and provides an optimal signal-to-interference -noise ratio SINR and thus improves spectral efficiency of hybrid architecture.

A New Optimization Technique in Massive MIMO and LSAS using Hybrid Architecture and Channel Estimation Algorithm for 5G Networks

Hardware designs and analysis for variant receive space modulation techniques

In this paper, we consider the downlink of a massive multiple-input-multiple-output (MIMO) single user transmission system operating in the millimeter wave outdoor narrowband channel environment. We propose a novel receive spatial modulation architecture aimed to reduce the power consumption at the user terminal, while attaining a significant spectral efficiency and low bit error rate. The energy consumption reduction is obtained through the use of analog devices(amplitude detector), which reduces the number of radio frequency chains and analog-to-digital-converters (ADCs). The base station transmits spatial and modulation symbols per channel use. We show that the optimal spatial symbol detector is a threshold detector that can be implemented by using one bit ADC. We derive closed form expressions for the detection threshold at different signal-to-noise-ratio (SNR) regions. We derive expressions for the average bit error probability in the presence and absence of the threshold estimation error showing that a small number of pilot symbolsis needed. A performance comparison is done between the proposed system and fully digital MIMO showing that a suitable constellation selection can reduce the performance gap.

Receive Spatial Modulation for Massive MIMO Systems

In this paper, we consider the downlink of a multi-user multiple-input-multiple-output system operating at the millimeter wave band in an outdoor environment. In this band, receive spatial modulation (RSM) schemes have been shown to achieve good spectral efficiency-energy consumption trade-off for the single-user case by exploiting new transceiver architectures that use a single radio-frequency (RF) chain at the user terminal (UT). In this work, we propose a novel RSM scheme for multiple RF chains at the UT. With the goal of maximizing the spectral efficiency (SE), we consider analog switches at the UT that select which antennas are active. To minimize the power consumption at the BS, we include analog switches that control the ON/OFF status of RF chains such that the SE is higher than a given threshold. Moreover, we extend the RSM concept to multiple users transmission. Specifically, we propose an algorithm that jointly optimizes the number of users, set of antennas and transmit power allocated to each user to maximize the sum SE. Simulation results show that RSM outperforms conventional modulation (no spatial symbols are transmitted) in terms of spectral and energy efficiency. Moreover, the proposed algorithms tightly approach the exhaustive search and outperform the prior art in terms of performance and convergence.

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Downlink Multi-User Massive MIMO Transmission Using Receive Spatial Modulation

Receive spatial modulation (RSM) schemes enable simple and energy efficient multiple-input-multiple-output (MIMO) transceivers and yet attain high spectral efficiency, which renders them promising schemes for millimeter wave (mmWave) communication in massive MIMO systems When these schemes are designed to include zero forcing (ZF) precoders, performance can be impaired in the presence of highly spatially correlated channels Extending these schemes for minimum mean square error (MMSE) precoding is not trivial due to the hardware constraints of the energy efficient user terminal architecture In this paper, we adapt the MMSE precoder to the low complexity RSM architecture and develop detection methods for the spatial and modulation symbols The proposed MMSE RSM scheme with total and per-antenna power constraints have been compared with ZF RSM in terms of average and outage mutual information by simulations showing superior gain for mmWave channels

/pdf/mmse-precoding-for-receive-spatial-modulation-in-large-mimo-j1srfocbel.pdf

MMSE Precoding for Receive Spatial Modulation in Large MIMO Systems

We consider a point to point large-scale multiple-input multiple-output (MIMO) system operating in the millimeter wave (mmWave) band and an outdoor scenario. Novel transmit and receive spatial modulation (SM) schemes are proposed for uplink (UL) and downlink (DL) data transmission phases based on a novel energy efficient hybrid user terminal architecture. The analog circuitry of the proposed hybrid architecture is divided into two stages: phase shifters and analog switches. The phase shifting stage assures high gain and overcomes the severe path-loss caused by outdoor mmWave propagation. The analog switching stage smartly allocates the antennas to be used at the phase shifting stage and combats the spatial correlation. We provide the analysis of the spectral efficiency $({{SE}})$ of the UL and DL systems. Next, we propose a reduced complexity algorithm that jointly optimizes the analog beamformer and combiner design of the UL and DL circuitry to maximize the energy efficiency $({{EE}})$ . Finally, we compare and evaluate the performance of the proposed algorithm in terms of the ${{SE}}$ and ${{EE}}$ assuming both stochastic and realistic channel models.

/pdf/energy-efficient-transmit-receive-hybrid-spatial-modulation-4k2madh2qj.pdf

Ahmed Raafat

Papers

Receive Spatial Modulation for Massive MIMO Systems

Receive Antenna Selection and Hybrid Precoding for Receive Spatial Modulation in Massive MIMO Systems

Downlink Multi-User Massive MIMO Transmission Using Receive Spatial Modulation

MMSE Precoding for Receive Spatial Modulation in Large MIMO Systems

Energy Efficient Transmit-Receive Hybrid Spatial Modulation for Large-Scale MIMO Systems