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In this paper, we seek to characterize the performance of spatial modulation (SM) and spatial multiplexing (SMX) with an experimental testbed. Two National Instruments (NI) PXIe devices are used for the system testing: one for the transmitter and one for the receiver. The digital signal processing (DSP) that formats the information data in preparation for transmission is described, along with the DSP that recovers the information data. In addition, the hardware limitations of the system are also analyzed. The average bit-error ratio (ABER) of the system is validated through both theoretical analysis and simulation results for SM and SMX under the line-of-sight (LoS) channel conditions. [ABSTRACT FROM PUBLISHER]

A wireless communication system using Chirp Spread Spectrum Modulation (CSSM) is analyzed in this study while assuming mobile nodes. CSSM exhibits promising error performance under very low signal-to-noise ratio values. Thereby, CSSM has been adopted in systems that generate low data traffic over long distances, such as low-power wireless networks. Existing studies reveal the significant advantages of CSSM system assuming static nodes. Yet, this article extends the existing analysis by considering mobile nodes. In particular, the error performance of CSSM system under random waypoint mobility model and fading scenarios is investigated. Specifically, Rayleigh fading and Additive White Gaussian Noise (AWGN) channels along with one-dimensional (line), two-dimensional (circle), and three-dimensional (sphere) mobility conditions are considered. A closed-form expression for the average bit error rate (BER) of CSSM system is derived and thoroughly discussed. In addition, simplified asymptotic expressions are obtained for the derived average BER at pragmatic signal to noise ratio (SNR) values along with an approximate expressions assuming pure orthogonal spreading factors. Monte-Carlo simulations are provided to corroborate the accuracy of the conducted analysis, where close-match is reported for wide range of system and channel parameters. In addition, it is reported that distance has considerable impact on the performance, whereas higher mobility dimension induces negligible degradation in performance. [ABSTRACT FROM AUTHOR]

Performance analysis, in terms of the (ABER), mutual information and theoretical capacity, for sparse code multiple access (SCMA) with variant multiple-input multiple-output (MIMO) techniques is presented and thoroughly discussed in this article. In particular, novel combination between space modulation techniques (SMTs) and SCMA is proposed and analyzed. As well, the performance of spatial multiplexing (SMX)-SCMA MIMO system is presented and used as a benchmark for the sake of comparison. Additionally, several designs for the mother constellation (MC) matrices are studied and their impact on the performance of the considered MIMO system is investigated. It is reported that different MC designs can lead to different performance and the performance of both MIMO systems can be optimized based on the considered codebook design. The closed-form analytical upper bound of the ABER over Rayleigh, Rician and Nakagami- m fading channels is derived and corroborated through Monte Carlo simulation results. Also, the theoretical capacity and the mutual information for SCMA–SMTS and SCMA–SMX MIMO systems are derived and studied over the considered fading channels. Monte-Carlo simulation results reveal that the derived capacity is the true upper bound for the simulated mutual information results and the conditions under which the capacity can be achieved are discussed. The performances of the considered SCMA–MIMO systems are compared to (OFDMA)–MIMO systems and significant gains are reported. [ABSTRACT FROM AUTHOR]

Asymmetric free space optical wireless sensor networks (FSO‐WSNs) have gained momentous attention lately due to the promise of minimal energy consumption at the distributed sensors along with eminent performance. Asymmetric FSO is accomplished using corner cube retroreflector (CCR) that is mounted on each sensor node. The CCR either reflects or absorbs the received laser beam from the fusion center to indicate its local decision regarding the monitored target. In this study, a bistatic channel is assumed where the transmitter and the receiver are located at different locations such that the double pass channel is modeled as a product of two independent turbulence channels. Novel performance analysis of the CCR‐based FSO‐WSN system in terms of the average bit error rate (BER) and the average decision error rate (DER) is presented. In particular, closed‐form expressions for the BER and the DER are derived using the Fox H‐function under different bistatic turbulent channel models including negative exponential, K‐turbulence, Gamma‐Gamma, and Malaga channel models. Monte Carlo simulation results are obtained to corroborate the accuracy of the derived analytical formulas where an exact match is reported over wide range of system and channel parameters. In addition, the influence of transmit power, distance, detection threshold, and turbulence parameters on the performance of the system is investigated and thoroughly discoursed. [ABSTRACT FROM AUTHOR]

Quadrature spatial modulation (QSM) multiple-input multiple-output system attracted substantial research interests lately driven by the several promised advantages. As well, cooperative communication is well-known to enhance the diversity gain and the overall system performance. In this paper, the theoretical capacity of amplify and forward (AF)-QSM system is derived and analyzed. In particular, the mutual information is first obtained and used to obtain the capacity. Derived formulas are corroborated through Monte Carlo simulation results over wide range of system and channel parameters. Besides, the impact of various parameters on the capacity and the mutual information of the studied system is investigated. The performance of AF-QSM is compared with AF-spatial modulation system and superior gains are reported. It is revealed that the capacity of AF-QSM is independent of the channel fading distribution where Rayleigh, Rician and Nakagami-m fading channels are considered. It is also reported that increasing the number of transmit antennas enhances the performance whereas increasing the number of relays degrades the performance. [ABSTRACT FROM AUTHOR]

Hardware designs for variant receive space modulation techniques (RSMTs) containing a reduced number of hardware components are proposed in this study. RSMTs rely on precoding of transmitted signals through channel knowledge at the transmitter to spatially modulate the receive antennas. As such, certain receive antennas will only receive messages while all other antennas will not receive any signal. It has been debated in literature that different RSMTs can be designed with single radio frequency (RF) chain receiver. Yet, practical designs are not yet available in literature. In this paper, a family of receiver designs for RSMTs based on commercial off‐the‐shelf components (COTS) are proposed and analyzed. Average error probability, power consumption, cost, and receiver complexity of the different techniques are presented and discussed. Additionally, Simulink models for all these systems are developed and presented. It is revealed that all RSMTs, in fact, do not require more than a single RF chain receiver or in some cases no RF chain, just by utilizing COTS components. Hardware designs for variant receive space modulation techniques (RSMTs) are presented in this study. By leveraging precoding at the transmitter, more efficient implementations can be achieved. This study furnishes and compares a variety of hardware system models that can be implemented to achieve those implementations. [ABSTRACT FROM AUTHOR]

Abstract: Space modulation techniques (SMTs) are a group of multiple‐input–multiple‐output wireless systems in which the spatial indexes of transmit antennas are utilized to convey additional information bits. The SMTs promise significant enhancements in terms of spectral and energy efficiencies and attract significant research interest in literature. Several SMTs have been proposed including spatial modulation (SM) and quadrature SM. In this study, the performance of dual‐hop decode‐and‐forward relaying SM and quadrature SM in the presence of wireless power transfer is analyzed and thoroughly discussed. Specifically, we derive exact closed‐form expressions for the pairwise error probability (PEP). In addition, we derive simple and accurate asymptotic expressions for the PEP at high signal‐to‐noise ratio, which provides insight into the influence of different system parameters. The obtained PEP expressions are then employed to evaluate the overall average bit error rate (BER). It is worth highlighting that the derived expressions are unified in the sense that they are valid for the aforementioned SMTs and for two well‐known practical energy harvesting protocols, namely, power‐splitting receiver and time‐switching receiver. In addition, we derive a unified closed‐form expressions for the outage probability and achievable throughput at the destination node. The impact of diverse system parameters, such as the power‐splitting factor, the energy‐harvesting time factor, and the distance between the source and the relay nodes, on the overall system performance is studied. The accuracy of the analytical derivations is validated through Monte Carlo simulations results. [ABSTRACT FROM AUTHOR]

This article presents a study on the real-time performance and practical implementation of several 5G channel coding candidates including low-density parity check (LDPC), polar, turbo, and convolutional channel codes. The experiment was conducted using a wireless communication transceiver system implemented on a software defined radio (SDR) platform called Universal Software Radio Peripheral (USRP). The system was implemented using Matlab software and included scrambling, channel coding, interleaving, and required synchronization and estimation blocks. Various sets of system and channel parameters were tested, including the impact of information block sizes, code lengths, and modulation orders on the performance of each channel coding technique. The study also evaluated the impact of hardware impairments and the required blocks to mitigate them. The results indicated that polar codes had the best performance, while other codes had trade-offs for various system parameters. The study concludes that polar codes with cyclic redundancy check-successive cancellation list (CRC-SCL) are the most reliable 5G channel coding candidates. [ABSTRACT FROM AUTHOR]

Recently, a revised model for the Nakagami- m multiple-input multiple-output (MIMO) channel has been proposed, yielding distinct results and conclusions compared to the existing model. This article focuses on evaluating and discussing the performance of MIMO space modulation techniques (SMTs) transmission schemes, namely space shift keying (SSK), quadrature space shift keying (QSSK), spatial modulation (SM), and quadrature spatial modulation (QSM), over the revised channel model. The evaluation considers spatial correlation, imperfect channel state information (CSI), and examines various performance metrics such as average bit error rate (ABER), mutual information, and capacity. Specifically, a closed-form expression for the ABER is derived under the assumption of a maximum-likelihood (ML) receiver. Additionally, formulas for mutual information and capacity are derived and thoroughly discussed. To validate the derived formulas, extensive Monte Carlo simulations are performed. Furthermore, the impact of system parameters on the ABER, mutual information, and capacity is investigated, providing a comprehensive analysis of their variations. A comparative study is conducted between different transmission schemes using the revised model, elucidating their relative performance. Moreover, a comparison is made between the reported results of the revised model and the existing Nakagami- m model, as well as other channel distributions such as Rayleigh and Rice fading channels. The findings clearly demonstrate the disparities between the existing and revised models, with the revised model exhibiting superior performance. Notably, when comparing the scenario of m = 1 with a Rayleigh fading channel, an exact match is observed for the revised channel model, while some differences are detected for the existing model. [ABSTRACT FROM AUTHOR]

In this paper, the performance analysis of spatial modulation and space shift keying multiple-input multiple-output techniques over generalised α − μ and κ − μ fading channels with imperfect channel state information at the receiver is presented. In particular, the pair-wise error probability (PEP) of the systems under study is derived. The PEP expression jointly considers the envelope and the phase distributions of the fading channels. The obtained PEP is then used to derive an upper bound closed-form expression for the average bit error rate. The influence of the fading parameters (i.e. α, κ and μ) and the channel estimation error on the system performance are analysed and discussed through representative numerical examples. The correctness of the conducted analysis is validated by means of Monte-Carlo simulations. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: FSO links have attracted a significant amount of interest in the recent years driven by the paramount importance of their license‐free spectrum and ease of deployment in wireless networks. Besides, the energy harvesting (EH) paradigm allows recharging terminals via ambient and/or external sources and prolongs battery lifetime operation. Thereby, facilitating free space optical (FSO) in EH networks creates potential scenarios for the future sixth‐generation (6G) communication systems. In this study, an EH system performing simultaneous wireless information and power transfer (SWIPT) while adopting FSO and resonant beam charging (RBC), RBC–SWIPT system is thoroughly analyzed. The performance of RBC‐SWIPT system is analyzed through Monte Carlo simulations, where average bit error ratio (ABER) and energy efficiency (EE) are studied and evaluated. In addition, channel capacity is derived along with the mutual information and studied over indoor line of sight (LOS) optical channel. Monte Carlo simulation results corroborate the accuracy of the derived formulas. [ABSTRACT FROM AUTHOR]

In this paper, Sphere Decoding (SD) algorithms for Spatial Modulation (SM) are developed to reduce the computational complexity of Maximum—Likelihood (ML) detectors. Two SDs specifically designed for SM are proposed and analysed in terms of Bit Error Ratio (BER) and computational complexity. Using Monte Carlo simulations and mathematical analysis, it is shown that by carefully choosing the initial radius the proposed sphere decoder algorithms offer the same BER as ML detection, with a significant reduction in the computational complexity. A tight closed form expression for the BER performance of SM—SD is derived in the paper, along with an algorithm for choosing the initial radius which provides near to optimum performance. Also, it is shown that none of the proposed SDs are always superior to the others, but the best SD to use depends on the target spectral efficiency. The computational complexity trade—off offered by the proposed solutions is studied via analysis and simulation, and is shown to validate our findings. Finally, the performance of SM—SDs are compared to Spatial Multiplexing (SMX) applying ML decoder and applying SD. It is shown that for the same spectral efficiency, SM—SD offers up to 84% reduction in complexity compared to SMX—SD, with up to 1 dB better BER performance than SMX—ML decoder. [ABSTRACT FROM AUTHOR]