On the energy efficiency of spatial modulation concepts

Spatial Modulation (SM) is a Multiple-Input Multiple-Output (MIMO) transmission technique which realizes low complexity implementations in wireless communication systems. Due the transmission principle of SM, only one Radio Frequency (RF) chain is required in the transmitter. Therefore, the complexity of the transmitter is lower compared to the complexity of traditional MIMO schemes, such as Spatial MultipleXing (SMX). In addition, because of the single RF chain configuration of SM, only one Power Amplifier (PA) is required in the transmitter. Hence, SM has the potential to exhibit significant Energy Efficiency (EE) benefits. At the receiver side, due to the SM transmission mechanism, detection is conducted using a low complexity (single stream) Maximum Likelihood (ML) detector. However, despite the use of a single stream detector, SM achieves a multiplexing gain. A point-to-point closed-loop variant of SM is receive space modulation. In receive space modulation, the concept of SMis extended at the receiver side, using linear precoding with Channel State Information at the Transmitter (CSIT). Even though receive space modulation does not preserve the single RF chain configuration of SM, due to the deployed linear precoding, it can be efficiently incorporated in a Space Division Multiple Access (SDMA) or in a Virtual Multiple-Input Multiple-Output (VMIMO) architecture. Inspired by the potentials of SM, the objectives of this thesis are the evaluation of the EE of SM and its extension in different forms of MIMO communication. In particular, a realistic power model for the power consumption of a Base Station (BS) is deployed in order to assess the EE of SM in terms of Mbps/J. By taking into account the whole power supply of a BS and considering a Time Division Multiple Access (TDMA) multiple access scheme, it is shown that SM is significantly more energy efficient compared to the traditional MIMO techniques. In the considered system setup, it is shown that SM is up to 67% more energy efficient compared to the benchmark systems. In addition, the concept of space modulation is researched at the receiver side. Specifically, based on the union bound technique, a framework for the evaluation of the Average Bit Error Probability (ABEP), diversity order, and coding gain of receive space modulation is developed. Because receive space modulation deploys linear precoding with CSIT, two new precoding methods which utilize imperfect CSIT are proposed. Furthermore, in this thesis, receive space modulation is incorporated in the broadcast channel. The derivation of the theoretical ABEP, diversity order, and coding gain of the new broadcast scheme is provided. It is concluded that receive space modulation is able to outperform the corresponding traditional MIMO scheme. Finally, SM, receive space modulation, and relaying are combined in order to form a novel virtual MIMO architecture. It is shown that the new architecture practically eliminates or reduces the problem of the inefficient relaying of the uncoordinated virtual MIMO space modulation architectures. This is undertaken by using precoding in a novel fashion. The evaluation of the new architecture is conducted using simulation and theoretical results

A virtual MIMO dual-hop architecture based on hybrid spatial modulation

International audienceIn this paper, we propose a novel Virtual Multiple-Input-Multiple-Output (VMIMO) architecture based on the concept of Spatial Modulation (SM). Using a dual-hop and Decode-and-Forward protocol, we form a distributed system, called Dual-Hop Hybrid SM (DH-HSM). DH-HSM conveys information from a Source Node (SN) to a Destination Node (DN) via multiple Relay Nodes (RNs). The spatial position of the RNs is exploited for transferring information in addition to, or even without, a conventional symbol. In order to increase the performance of our architecture, while keeping the complexity of the RNs and DN low, we employ linear precoding using Channel State Information (CSI) at the SN. In this way, we form a Receive-Spatial Modulation (R-SM) pattern from the SN to the RNs, which is able to employ a centralized coordinated or a distributed uncoordinated detection algorithm at the RNs. In addition, we focus on the SN and propose two regularized linear precoding methods that employ realistic Imperfect Channel State Information at the Transmitter. The power of each precoder is analyzed theoretically. Using the Bit Error Rate (BER) metric, we evaluate our architecture against the following benchmark systems: 1) single relay; 2) best relay selection; 3) distributed Space Time Block Coding (STBC) VMIMO scheme; and 4) the direct communication link. We show that DH-HSM is able to achieve significant Signal-to-Noise Ratio (SNR) gains, which can be as high as 10.5 dB for a very large scale system setup. In order to verify our simulation results, we provide an analytical framework for the evaluation of the Average Bit Error Probability (ABEP)

EL LABORATORIO DE CIENCIAS DE LA FUTURA ESCUELA. TECNOLOGÍAS Y CONTENIDOS EMERGENTES

Este artigo investiga as tendências atuais na transformação de laboratórios STEM na era da digitalização devido à integração de tecnologias digitais e ao reconhecimento da importância do desenvolvimento de habilidades metacognitivas. O artigo examina o papel da metacognição e seu impacto no processo de aprendizagem, bem como o uso de tecnologias digitais, como laboratórios remotos, laboratórios virtuais, realidade aumentada, realidade virtual e dispositivos móveis na educação STEM. Os resultados desta pesquisa sugerem que o uso dessas tecnologias digitais pode ser benéfico para a aprendizagem de ciências no ensino superior e secundário. Além disso, essas tecnologias podem ser usadas para promover o engajamento, a colaboração e o acesso dos alunos ao conhecimento científico. Além disso, a metacognição é uma habilidade importante para professores e alunos, e pode ser desenvolvida através do uso da pirâmide do conhecimento, pirâmide de inteligência emocional, pirâmide metacognitiva e modelos de pirâmide de superdotação.This paper investigates the current trends in the transformation of STEM laboratories in the age of digitization due to the integration of digital technologies and the recognition of the importance of developing metacognitive skills. The paper examines the role of metacognition and its impact on the learning process, as well as the use of digital technologies such as remote labs, virtual labs, augmented reality, virtual reality, and mobile devices in STEM education. Results from this research suggest that the use of these digital technologies can be beneficial for science learning in both higher and secondary education. Additionally, these technologies can be used to promote student engagement, collaboration, and access to scientific knowledge. Furthermore, metacognition is an important skill for both teachers and students, and can be developed through the use of the knowledge pyramid, emotional intelligence pyramid, metacognitive pyramid, and giftedness pyramid models.Este artículo investiga las tendencias actuales en la transformación de los laboratorios STEM en la era de la digitalización debido a la integración de tecnologías digitales y al reconocimiento de la importancia del desarrollo de habilidades metacognitivas. El documento examina el papel de la metacognición y su impacto en el proceso de aprendizaje, así como el uso de tecnologías digitales como laboratorios remotos, laboratorios virtuales, realidad aumentada, realidad virtual y dispositivos móviles en la educación STEM. Los resultados de esta investigación sugieren que el uso de estas tecnologías digitales puede ser beneficioso para el aprendizaje de las ciencias tanto en la educación superior como en la secundaria. Además, estas tecnologías pueden utilizarse para promover la participación, colaboración y acceso al conocimiento científico por parte de los estudiantes. Además, la metacognición es una habilidad importante tanto para profesores como para estudiantes y puede desarrollarse mediante el uso de los modelos de pirámide del conocimiento, pirámide de inteligencia emocional, pirámide metacognitiva y pirámide de talento.Este artigo investiga as tendências atuais na transformação de laboratórios STEM na era da digitalização devido à integração de tecnologias digitais e ao reconhecimento da importância do desenvolvimento de habilidades metacognitivas. O artigo examina o papel da metacognição e seu impacto no processo de aprendizagem, bem como o uso de tecnologias digitais, como laboratórios remotos, laboratórios virtuais, realidade aumentada, realidade virtual e dispositivos móveis na educação STEM. Os resultados desta pesquisa sugerem que o uso dessas tecnologias digitais pode ser benéfico para a aprendizagem de ciências no ensino superior e secundário. Além disso, essas tecnologias podem ser usadas para promover o engajamento, a colaboração e o acesso dos alunos ao conhecimento científico. Além disso, a metacognição é uma habilidade importante para professores e alunos, e pode ser desenvolvida através do uso da pirâmide do conhecimento, pirâmide de inteligência emocional, pirâmide metacognitiva e modelos de pirâmide de superdotação

Performance Analysis of Multistream Receive Spatial Modulation in the MIMO Broadcast Channel

International audienceIn 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

On the Performance of Multi-Stream Receive Spatial Modulation in the MIMO Broadcast Channel

International audienceIn this paper, a novel architecture for the Multiple-Input Multiple-Output (MIMO) broadcast channel is proposed and studied. The new architecture is based on the concept of Multi- Stream Receive-Spatial Modulation (MSR-SM). MSR-SM is a closed-loop transmission scheme, which applies the concept of multi-stream space modulation at the receiver side. A new and accurate framework for computing the Average Bit Error Probability (ABEP) of the new architecture is proposed. In addition, the new architecture is compared against the state- of-the-art MIMO transmission in the broadcast channel and it is shown to: i) provide superior Bit Error Rate (BER) performance in the high Signal-to-Noise-Ratio (SNR) regime and ii) reduce the signal processing complexity at the transmitter

On the Asymptotic Performance of Receive Space Modulation in the Shadowing Broadcast Channel

International audienceIn this letter, the diversity order and the coding gain of Receive Space Modulation (RSM) in the Multiple-Input Multiple-Output (MIMO) broadcast channel are derived by taking into account both small and large scale fading. The considered linear precoding method is Zero Forcing (ZF). Note that the proposed framework is directly applicable to the conventional spatially multiplexed broadcast channel. Based on the derived mathematical framework, a theoretical criterion is provided, which determines the superiority between the deployment of RSM and Spatial MultipleXing (SMX) in the shadowing MIMO broadcast channel. Finally, the provided theoretical results are validated via Monte Carlo simulation results

6G Positioning and Sensing Through the Lens of Sustainability, Inclusiveness, and Trustworthiness

6G promises a paradigm shift in which positioning and sensing are inherently integrated, enhancing not only the communication performance but also enabling location- and context-aware services. Historically, positioning and sensing have been viewed through the lens of cost and performance trade-offs, implying an escalated demand for resources, such as radio, physical, and computational resources, for improved performance. However, 6G goes beyond this traditional perspective to encompass a set of broader values, namely sustainability, inclusiveness, and trustworthiness. This paper aims to: (i) shed light on these important value indicators and their relationship with the conventional key performance indicators, and (ii) unveil the dual nature of 6G in relation to these key value indicators (i.e., ensuring operation according to the values and enabling services that affect the values)

Precoding-Aided Spatial Modulation for the Wiretap Channel with Relay Selection and Cooperative Jamming

We propose in this paper a physical-layer security (PLS) scheme for dual-hop cooperative networks in an effort to enhance the communications secrecy. The underlying model comprises a transmitting node (Alice), a legitimate node (Bob), and an eavesdropper (Eve). It is assumed that there is no direct link between Alice and Bob, and the communication between them is done through trusted relays over two phases. In the first phase, precoding-aided spatial modulation (PSM) is employed, owing to its low interception probability, while simultaneously transmitting a jamming signal from Bob. In the second phase, the selected relay detects and transmits the intended signal, whereas the remaining relays transmit the jamming signal received from Bob. We analyze the performance of the proposed scheme in terms of the ergodic secrecy capacity (ESC), the secrecy outage probability (SOP), and the bit error rate (BER) at Bob and Eve. We obtain closed-form expressions for the ESC and SOP and we derive very tight upper-bounds for the BER. We also optimize the performance with respect to the power allocation among the participating relays in the second phase. We provide examples with numerical and simulation results through which we demonstrate the effectiveness of the proposed scheme

Energy evaluation of spatial modulation at a multi-antenna base station

International audienceIn this paper, we aim to study the Energy Efficiency (EE) of Spatial Modulation (SM) at different Base Stations (BSs) taking into account the total power consumption. Compared to conventional Multiple-Input Multiple-Output (MIMO) schemes, SM benefits from a single Radio Frequency (RF) chain which results in decreased power supply (W), higher EE (Mbits/J), and reduced complexity. Using the fundamental limits of Shannon capacity, we show that SM achieves a range of average data rates with only a fraction, which can be as low as 24% for four transmit antennas, of the total power supply of conventional MIMO. In addition, we demonstrate that the EE of the studied schemes is maximized for a certain average data rate and that SM achieves the highest EE among them. Finally, we note that a BS employing SM can be up to 67% more energy efficient compared to a BS under a conventional MIMO transmission scheme, for four transmit antennas