RIS Group Number Modulation Assisted Receive Spatial Modulation

Receive spatial modulation (RSM) schemes are promising for massive multiple-input-multiple-output (MIMO) systems at millimeter wave (mmWave) bands because they require reduced complexity and low consumption hardware at the user terminal and exploit the receive spatial dimension to attain high spectral efficiency. To the best of our knowledge, these schemes have been developed for narrowband transmission. In this paper, we adapt RSM schemes for outdoor wideband mmWave massive MIMO systems. We consider the downlink of a single user system operating with single carrier RSM and design a low complexity time-domain finite impulse response pre-equalizer to combat the intersymbol interference caused by the wideband transmission, assuming imperfect channel knowledge. We show that receive antenna selection (RAS) is necessary for attaining high spectral efficiency and we suggest fast and efficient RAS algorithm. Simulation results show that the proposed RSM scheme achieves comparable spectral efficiency to the fully digital orthogonal frequency division multiplexing MIMO system with superior energy efficiency.

Receive spatial modulation (RSM) is one of the recently evolved transmission schemes that show an unprecedented decrease in the computational and hardware complexity at the receiver end. In this letter, we propose an enhanced transmit-receive SM (ETRSM) by partitioning the antennas at the transmitter and receiver and by invoking the SM concept across the groups for massive MIMO systems. Moreover, considering the generalized multiple measurement vectors (GMMV), recovery of information from the received signal is modeled as a joint sparse signal recovery problem in the compressive sensing (CS) framework. Besides, we propose a low complexity receiver algorithm, structured generalized orthogonal matching pursuit (sgOMP) GMMV, and present appropriate numerical results to substantiate our ideas.

Today's wireless communication networks have many requirements such as high data rate, high reliability, low latency, low error data transmission, and high energy efficiency. High-performance index modulation (IM) techniques and reconfigurable intelligent surface (RIS) technology, which has recently attracted the attention of researchers, are strong candidates to meet these requirements. This paper introduces a novel RIS-supported code IM-based receive spatial modulation (RIS-CIM-RSM) system. The proposed RIS-CIM-RSM system uses quadrature amplitude modulation (QAM) symbols, receive antenna indices, and spreading code indices for wireless data transmission. In the proposed system, an RIS applies a phase rotation that maximizes signal-to-noise ratio (SNR) to the signals coming to the reflecting elements and directs them to the selected receive antenna. Performance analyses of the proposed RIS-CIM-RSM system such as data rate, throughput, and energy saving are obtained. The results obtained show that the proposed RIS-CIM-RSM system is superior to the counterpart RIS-based IM systems in the literature in terms of data rate, throughput, energy saving, and error performance.

Receive spatial modulation (RSM) has been proposed as an effective transmission technology for next-generation wireless communications systems because of its reduced complexity and low energy consumption at the receiver end. Compared to conventional multiple-input multiple-output (MIMO) transceivers, which require one radio-frequency (RF) chain and analog-to-digital converter (ADC) per receive antenna, RSM can be implemented with one amplitude detector per antenna and a single RF chain, with mild performance degradation in terms of spectral efficiency (SE). However, its implementation using zero-forcing precoders is inadequate in mmWave channels due to the lack of propagation scattering and, hence, rank deficiency in the channel matrix. This has been only partially solved in the past using receiver antenna selection (RAS), which requires additional receive antennas. On the other hand, using reconfigurable intelligent surfaces (RIS), which can effectively create scatter and enhance the channel matrix rank, is an affordable solution that can also cope with shadowing situations and the higher path losses associated with mmWave bands. We propose using a RIS in a single-user MIMO communication with RSM to improve the downlink transmission. This paper shows that RIS-assisted RSM communication is more than a good option in mmWave channels in terms of bit error rate due to the multipath induced in the channel and the link budget boosting.

Receive spatial modulation (RSM) schemes<br> are promising for massive multiple-input-multiple-output<br> (MIMO) systems at millimeter wave (mmWave) bands<br> because they require reduced complexity and low consumption<br> hardware at the user terminal and exploit the<br> receive spatial dimension to attain high spectral efficiency.<br> To the best of our knowledge, these schemes have been<br> developed for narrowband transmission. In this paper,<br> we adapt RSM schemes for outdoor wideband mmWave<br> massive MIMO systems. We consider the downlink of<br> a single user system operating with single carrier RSM<br> and design a low complexity time-domain finite impulse<br> response pre-equalizer to combat the intersymbol interference<br> caused by the wideband transmission, assuming imperfect<br> channel knowledge. We show that receive antenna<br> selection (RAS) is necessary for attaining high spectral<br> efficiency and we suggest fast and efficient RAS algorithm.<br> Simulation results show that the proposed RSM scheme<br> achieves comparable spectral efficiency to the fully digital<br> orthogonal frequency division multiplexing MIMO system<br> with superior energy efficiency.

In this paper, Multi-Stream Receive-Spatial Modulation (MSR-SM) for application to the Multiple-Input Multiple-Output (MIMO) broadcast channel is introduced and studied. MSR-SM is a closed-loop transmission scheme, which applies the concept of multistream space modulation at the receiver side. An accurate mathematical framework for the evaluation of the Bit Error Rate (BER) is proposed. In addition, the diversity order and coding gain of the new architecture are derived. Note that the proposed analytical framework takes into account both the small-scale fading and the system topology, and is directly applicable to the conventional MIMO broadcast channel. Compared with the state-of-the-art MIMO transmission in the broadcast channel, it is mathematically shown that MSR-SM achieves the same diversity order and a better coding gain, in the high Signal-to-Noise Ratio (SNR) regime. Finally, the proposed mathematical framework and the new findings are validated via Monte Carlo simulation results.