Wireless Communication Solutions Research Articles

From wires to waves, a novel sensor system for in vivo pressure monitoring.

Pressure monitoring in various organs of the body is essential for appropriate diagnostic and therapeutic purposes. In almost all situations, monitoring is performed in a hospital setting. Technological advances not only promise to improve clinical pressure monitoring systems, but also engage toward the development of fully implantable systems in ambulatory patients. Such systems would not only provide longitudinal time monitoring to healthcare personnel, but also to the patient who could adjust their way-of-life in response to the measurements. In the past years, we have developed a new type of piezoresistive pressure sensor system. Different bench tests have demonstrated that it delivers precise and reliable pressure measurements in real-time. The potential of this system was confirmed by a continuous recording in a patient that lasted for almost a day. In the present study, we further characterized the functionality of this sensor system by conducting in vivo implantation experiments in nine female farm pigs. To get a step closer to a fully implantable system, we also adapted two different wireless communication solutions to the sensor system. The communication protocols are based on MICS (Medical Implant Communication System) and BLE (Bluetooth Low Energy) communication. As a proof-of-concept, implantation experiments in nine female pigs demonstrated the functionality of both systems, with a notable technical superiority of the BLE.

Integrated lithium niobate microwave photonic processing engine.

Integrated microwave photonics (MWP) is an intriguing technology for the generation, transmission and manipulation of microwave signals in chip-scale optical systems1,2. In particular, ultrafast processing of analogue signals in the optical domain with high fidelity and low latency could enable a variety of applications such as MWP filters3-5, microwave signal processing6-9 and image recognition10,11. An ideal integrated MWP processing platform should have both an efficient and high-speed electro-optic modulation block to faithfully perform microwave-optic conversion at low power and also a low-loss functional photonic network to implement various signal-processing tasks. Moreover, large-scale, low-cost manufacturability is required to monolithically integrate the two building blocks on the same chip. Here we demonstrate such an integrated MWP processing engine based on a 4 inch wafer-scale thin-film lithium niobate platform. It can perform multipurpose tasks with processing bandwidths of up to 67 GHz at complementary metal-oxide-semiconductor (CMOS)-compatible voltages. We achieve ultrafast analogue computation, namely temporal integration and differentiation, at sampling rates of up to 256 giga samples per second, and deploy these functions to showcase three proof-of-concept applications: solving ordinary differential equations, generating ultra-wideband signals and detecting edges in images. We further leverage the image edge detector to realize a photonic-assisted image segmentation model that can effectively outline the boundaries of melanoma lesion in medical diagnostic images. Our ultrafast lithium niobate MWP engine could provide compact, low-latency and cost-effective solutions for future wireless communications, high-resolution radar and photonic artificial intelligence.

Investigation on wireless communication reliability planning in cloud computing mMTC scenarios

With the development of cloud computing technology, cloud computing has been applied in various fields, but there is a lack of research in the Massive Machine Type Communication (mMTC) scenario. This article analyzed wireless communication reliability solutions in cloud computing mMTC scenarios to address this issue. Using the method of cloud computing, this article analyzed the reliability of wireless communication schemes and verified the effectiveness of the algorithm through credibility judgment and algorithm convergence characteristics under the guidance of wireless communication schemes. By analyzing the application of cloud computing in wireless communication solutions, this article analyzed the effectiveness of wireless communication solutions in the experimental section by comparing the error rate, success rate, and convergence of various algorithms. Through experimental analysis, it was found that the implementation success rate of chaotic particle swarm optimization algorithm was 5% higher than that of adaptive particle swarm optimization. The results indicated that cloud computing was well applied in wireless communication networks, thus providing reference significance for the application of cloud computing in other communication fields.

Channel Capacity Optimization Using Multiple-Input Multiple-Output for a Rayleigh Channel

The use of multiple-input multiple-output (MIMO) systems with multiple antenna elements provides an efficient solution for future wireless communication. In recent times, wireless communication has been characterized by high speed, higher data throughput, and high Bit Error Rate (BER) in a limited bandwidth. Low data speed handover, low Signal Noise Ratio (SNR), and hardware power drainage are common channel problems with wireless systems. The objective of this research seeks a way to optimize channel capacity and enhance system performance. The paper presents a comprehensive performance analysis of channel capacity under the Rayleigh fading channel using water water-filling technique. MATLAB was used to analyze and simulate the process. Simulation results revealed that the water-filling algorithm can effectively optimize channel capacity in the wireless communication system.

Experimental Results of Magnetic Communication Using the Giant Magnetoimpedance Receiver in Underwater Environments

This letter presents the topology of a novel approach to magnetic communication using a giant magnetoimpedance (GMI)-based receiver with a GMI sensor in underwater media such as freshwater. In addition, practical channel test results for the magnetic communication link of a GMI receiver in freshwater are first presented. For this test, a magnetic communication system using a GMI-based receiver, including triangularly arranged transmission coil antennas, was proposed. Wireless digital communication using quadrature phase shift keying (QPSK), which is less sensitive to noise and has a high data rate, was used to evaluate the proposed GMI receiver. Several performance metrics, such as constellation, data rate, and error vector magnitude, were measured at 20 kHz. The test results were meaningful, indicating that the proposed magnetic communication system using a GMI-based receiver can be a promising solution for wireless communication in extreme environments, such as underwater media.

Design and Simulation of Elliptical Shaped Microstrip Patch Antenna Using HFSS

Abstract: The elliptical patch antenna presents a comprehensive study on the design, fabrication, and performance analysis of an operating at 2.4 GHz, employing FR4 substrate material. The elliptical shape is chosen for its unique radiation characteristics and compact form factor, making it suitable for integration into modern wireless communication systems. The design process involves careful consideration of key parameters, including patch dimensions, feedline structure, and ground plane geometry. Advanced simulation tools, such as electromagnetic simulators, are employed to optimize the antenna's performance, achieving desirable characteristics such as low return loss and enhanced bandwidth. Utilizing FR4 as the substrate material offers several advantages, including costeffectiveness, ease of procurement, and compatibility with standard PCB manufacturing processes. The dielectric properties of FR4 are thoroughly analyzed and incorporated into the antenna design process to ensure accurate simulation results. The proposed elliptical patch antenna has promising applications in various wireless communication systems, including Wi-Fi, Bluetooth, and IoT devices, operating in the 2.4 GHz frequency band. Its compact size and robust performance make it a compelling choice for space-constrained and high-performance wireless communication applications. This contributes valuable insights into the design and optimization of patch antennas, particularly those using FR4 substrates, and serves as a foundation for the development of efficient and cost-effective wireless communication solutions in the 2.4 GHz spectrum.

Real and fake channel: GAN-based wireless channel modeling and generating

With the increasing complexity of wireless environment, scene, frequency band, antenna scale and other factors, it brings new challenges to wireless channel modeling. On the other hand, wireless communication solutions based on artificial intelligence have been constantly proposed in recent years, which are highly dependent on the quality and quantity of channel data. However, in the actual communication system, the acquisition of real channel data is restricted by the high cost of channel data acquisition. In this paper, an improved Wasserstein generative adversal network with gradient penalty (WGAN-GP) is proposed to solve the channel modeling and generation problem in MIMO communication system. The experimental results show that the improved WGAN-GP can generate fake channel data with the same distribution as the real channel data. In addition, the validity of the fake channel data is cross-verified by a channel feedback scheme based on deep learning.

Error resilient wireless video transmission via parallel processing using puncturing rule enabled coding and decoding

The innovation in wireless video transmission lies in the methodology's holistic approach, which combines parallel processing, puncturing rule-enabled coding, comprehensive error correction, and focused video frame reconstruction. The methodology includes several stages, including video frame processing, channel coding, error simulation, and Viterbi decoding, all of which are optimized for improved performance. Parallel processing is used at each stage to improve computational efficiency. Convolutional encoding is used concurrently, with a puncturing rule to tailor the encoding process for individual packets. Following that, a binary symmetric channel model is used to simulate bit errors, allowing the system's error-resilient characteristics to be evaluated. Beyond the analysis performed on previously studied videos, the proposed approach is thoroughly evaluated across three distinct video datasets. Furthermore, the study delves into BER analysis, encompassing various error probabilities and employing incremental redundancy. This investigation sheds light on the system's robustness in correcting errors in a variety of error scenarios. Throughput measurements provide important information about the achieved data transmission rate during successful receptions, whereas the elapsed time metric measures the overall efficiency of the transmission process. Furthermore, the proposed method assesses Mean Squared Error (MSE) at 0.48 and Peak Signal-to-Noise Ratio (PSNR) at 51.30 dB across the entire operational process. The combined findings highlight the proposed approach's superiority, positioning it as a promising solution for robust and efficient wireless video communication. This results in a more stable and efficient gearbox system, distinguishing it from existing system.

Flexible metasurfaces as sub-6 GHz frequency selective surfaces for 5G applications

The deployment of fifth-generation mobile network (5G), beyond 5G and sixth-generation mobile network platforms encounters challenges of blockage, interference, and path loss in radio mobile environments. Metasurfaces provide a promising solution to address these limitations. In this paper, we present a methodology for developing ultrathin flexible metasurface-based frequency selective surfaces (FSSs). Our approach combines thermal evaporation for metallic thin films with a macroscopic metasurface mask (something analogous to screen-printing but using thermal evaporation instead of inks). As a proof of concept, we fabricate a sub-6 GHz metasurface-based FSS using gold deposition on a flexible polyethylene terephthalate substrate. Experimental results are validated through numerical full-wave simulations using COMSOL Multiphysics and equivalent-circuit model simulations. The metasurface operates within the primary frequency band utilized in 5G networks (3–5 GHz), indicating its potential applicability across a wide range of flexible, conformal, and wearable devices. The fabricated FSS can be installed on surfaces of any shape, such as flat or curved windows, as well as on walls or other external surfaces. This methodology offers practical solutions for wireless communications and enhancing signal transmission in diverse environments.

Indoor Non‐Line‐of‐Sight Millimeter‐Wave Coverage Enhancements by Field‐Reorganizable Passive Digital Coding Metasurfaces

Digital metasurfaces define a novel methodology for metasurface designs by adopting discrete coding meta‐atoms to engineer electromagnetic waves in programmable ways. Herein, a novel field‐reorganizable digital metasurface (FRDM) that can be used to enhance the indoor non‐line‐of‐sight (NLOS) millimeter‐wave (mmWave) signal coverage is presented. The passive binary supercells which can be reorganized with an in situ optimization characteristic to deflect the incoming mmWaves into the blind area with adjustable angles are proposed. The indoor L‐shaped corridor signal coverage simulated by the ray‐tracing technique confirms that the NLOS blind area is effectively communicated using the passive FRDM. Practical environment experiments using FRDMs with different coding sequences are conducted, indicating that the averaged signal intensity is increased by over 10 dB in the NLOS blind area in a wide operating frequency band from 26 to 30 GHz by reorganizing the passive digital metasurfaces. The results suggest that the proposed FRDM enabled by the reorganizable binary supercells is a highly flexible, low‐cost, and extensible solution for B5G and 6G mmWave wireless communications.

Unveiling LoRa's Oceanic Reach: Assessing the Coverage of the Azores LoRaWAN Network from an Island.

In maritime settings, effective communication between vessels and land infrastructure is crucial, but existing technologies often prove impractical for energy-sensitive IoT applications, like deploying sensors at sea. In this study, we explore the viability of a low-power, cost-effective wireless communication solution for maritime sensing data. Specifically, we conduct an experimental assessment of the Azorean Long Range Wide Area Network (LoRaWAN) coverage. Our tests involve positioning the gateway at the island's highest point and installing end nodes on medium-sized fishing vessels. Through measurements of received signal strength indicator (RSSI), signal-to-noise ratio (SNR), and lines of sight (LOS), we showcase the potential of LoRaWAN transmissions to achieve communication distances exceeding 130 km in a LOS-free scenario over the ocean. These findings highlight the promising capabilities of LoRaWAN for reliable and long-range maritime communication of sensing data.

Advances in MIMO Antenna Design for 5G: A Comprehensive Review.

Multiple-input multiple-output (MIMO) technology has emerged as a highly promising solution for wireless communication, offering an opportunity to overcome the limitations of traffic capacity in high-speed broadband wireless network access. By utilizing multiple antennas at both the transmitting and receiving ends, the MIMO system enhances the efficiency and performance of wireless communication systems. This manuscript specifies a comprehensive review of MIMO antenna design approaches for fifth generation (5G) and beyond. With an introductory glimpse of cellular generation and the frequency spectrum for 5G, profound key enabling technologies for 5G mobile communication are presented. A detailed analysis of MIMO performance parameters in terms of envelope correlation coefficient (ECC), total active reflection coefficient (TARC), mean effective gain (MEG), and isolation is presented along with the advantages of MIMO technology over conventional SISO systems. MIMO is characterized and the performance is compared based on wideband/ultra-wideband, multiband/reconfigurable, circular polarized wideband/circular polarized ultra-wideband/circular polarized multiband, and reconfigurable categories. The design approaches of MIMO antennas for various 5G bands are discussed. It is subsequently enriched with the detailed studies of wideband (WB)/ultra-wideband (UWB), multiband, and circular polarized MIMO antennas with different design techniques. A good MIMO antenna system should be well decoupled among different ports to enhance its performance, and hence isolation among different ports is a crucial factor in designing high-performance MIMO antennas. A summary of design approaches with improved isolation is presented. The manuscript summarizes the various MIMO antenna design aspects for NR FR-1 (new radio frequency range) and NR FR-2, which will benefit researchers in the field of 5G and forthcoming cellular generations.

Large Frequency Ratio Antennas Based on Dual-Function Periodic Slotted Patch and its Quasi-Complementary Structure for Vehicular 5G Communications

Dual-function periodic slotted patch and its quasi-complementary structure in designing large frequency ratio antennas for vehicular 5G communications are presented in this paper. Firstly, a circular patch with periodic circular slots is employed as a partially reflecting surface (PRS) antenna in the millimeter-wave band. Simultaneously, the circular slotted patch is operated in the microwave band as a patch antenna, achieving dual functions. It is flexible to design the two antenna parts due to their polarization orthogonality. In the next place, with similar working principles, its quasi-complementary structure that contains periodic connected circular patches is also utilized for the large frequency ratio antenna design. As the proof of concept, two large frequency ratio antennas working in the 3.5-GHz and 28-GHz bands with a frequency ratio of 8 for 5G applications were designed. Finally, for verification, a periodic slotted patch antenna was fabricated and measured. Good agreement between the measured and simulated results is found. Measured -10-dB impedance bandwidths of 6.25% (3.41–3.63 GHz) and 20.57% (24.21–29.76 GHz), and measured peak antenna gains of 8.14 dBi and 14.04 dBi are obtained at the lower and upper bands, respectively. The antennas can be integrated solutions for vehicular-platform 5G microwave and millimeter-wave wireless communications.

Traffic grooming for massive light-path blockages in D2D-enabled hybrid LiFi and WiFi networks

Hybrid light-fidelity (LiFi) and wireless-fidelity (WiFi) networks (HLWNets) provide a promising solution for the future indoor wireless communications. This network structure faces the challenge of traffic congestion since LiFi links are prone to be blocked due to angular misalignment and path obstruction while WiFi has limited capacity. In this paper, a novel network structure that enables device-to-device (D2D) technology in HLWNets is considered. Then, traffic grooming (TG) for D2D-enabled HLWNets with massive light-path blockages is researched. By jointly handling mode selection, user pairing, and resource allocation, TG is formulated as a joint optimization problem. This can efficiently groom low-speed connections from WiFi onto high-capacity LiFi when massive light-path blockages occur, thus increasing network throughput. Next, a three-stage heuristic TG algorithm is developed to reduce the computational complexity required to solve the optimization problem. Finally, by simulation, the effectiveness of the proposed algorithm has been demonstrated. The simulation results indicate that the network throughput can be increased by up to 20% with the proposed algorithm. Besides, the proposed algorithm also has significant advantages in terms of Jain's fairness index and user satisfaction.

Integration of Optical and Free Space Optics Network Architecture for High-Speed Communication in Adverse Weather using suitable Optical Bands

Free Space Optics (FSO) is a highly viable solution for high-speed wireless communication and is widely preferred over radio frequency communication systems because of its faster data transmission, no regulatory requirements and highly secure long-range operations. However, the capacity and availability of FSO optical bands are a significant concern in varying atmospheric conditions. Our objective is to enhance network flexibility and expand wireless network coverage in adverse weather conditions by combining optical and FSO links using optical bands C, S, and O. The study analyzed the performance of a hybrid 4 channels FSO-WDM system with a 100GHz or 0.8 nm channel spacing under different conditions, including adverse weather and varying data rates. An attenuation of 0.25 dB/km was fixed, and the system's performance was analyzed up to 3 km. The results showed that as the data rate increased, the system's performance declined, and the O band was the best performer up to 25 Gbit/s. BER values were analyzed at different weather conditions using the Kim model, and the O band consistently outperformed the S and C bands. Eye diagrams were used to evaluate the signal quality, and the O band was shown to perform better than the other two bands, even in adverse weather conditions. Overall, the study suggests that FSO is a viable solution for high-speed wireless communication, particularly when using the O band.

Dual-Filter Architecture for Blind Feedback Recovery of the Symbol Timing in Bandlimited Optical Intensity Channels

Reliable recovery of transmission parameters is of paramount importance not only for radio frequency receivers, but also for optical wireless communication solutions. This paper discusses a feedback algorithm for recovering the symbol timing in the context of a bandlimited optical intensity link. The link is determined by a PAM scheme and pulse shaping with squared raised cosine or double jump functions. When preambles or pilot sequences are not available to the receiver, non-data-aided (blind) recovery concepts are useful for tracking smaller variations of the timing error affecting the payload data. The current state-of-the-art solution uses a Gardner detector with two samples per symbol, although this introduces a non-negligible amount of inter-symbol interference resulting in an error floor. To avoid this drawback, the authors propose a dual-filter approach which includes an appropriately designed filter operated in parallel to the receiver filter. Despite the additional complexity of the dual-filter architecture, the recovery loop is very simple and requires only one sample per symbol, representing the lowest degree of complexity in this respect. Open-loop characteristic, jitter performance, and acquisition behavior of the suggested recovery loop are investigated.

Cost-Efficient RIS-Assisted Transmitter Design With Discrete Phase Shifts for Wireless Communication

In this letter, in order to achieve higher spectral and energy efficiency, we propose a novel cost-efficient transmitter conceptual design based on reconfigurable intelligent surface (RIS) with discrete phase shifts. The key idea is to directly utilize the digital signal to adjust the discrete reflection coefficients of RIS, resulting that the phases of the reflected carrier signal being modulated without the need for complex digital signal processing (DSP) hardware and costly radio frequency (RF) chains. Furthermore, a joint digital modulation and beamforming method is developed to enable information transmission as well as enhance signal strength. Based on the proposed transmitter, we derive the closed-form expressions of the signal-to-noise ratio (SNR) and bit error rate (BER) of the received signal and analyze the impact of hardware constraints on communication performance. Extensive simulation results validate that the novel design of RIS-assisted transmitter provides a cost-effective and power-efficient solution for wireless communications.

A Survey on the Security Challenges of Low-Power Wireless Communication Protocols for Communicating Concrete in Civil Engineerings.

With the increase in low-power wireless communication solutions, the deployment of Wireless Sensor Networks is becoming usual, especially to implement Cyber-Physical Systems. These latter can be used for Structural Health Monitoring applications in critical environments. To ensure a long-term deployment, battery-free and energy-autonomous wireless sensors are designed and can be powered by ambient energy harvesting or Wireless Power Transfer. Because of the criticality of the applications and the limited resources of the nodes, the security is generally relegated to the background, which leads to vulnerabilities in the entire system. In this paper, a security analysis based on an example: the implementation of a communicating reinforced concrete using a network of battery-free nodes; is presented. First, the employed wireless communication protocols are presented in regard of their native security features, main vulnerabilities, and most usual attacks. Then, the security analysis is carried out for the targeted implementation, especially by defining the main hypothesis of the attack and its consequences. Finally, solutions to secure the data and the network are compared. From a global point-of-view, this security analysis must be initiated from the project definition and must be continued throughout the deployment to allow the use of adapted, updatable and upgradable solutions.

Resource allocation based on differentiated user services for indoor hybrid multi-color VLC/WiFi networks

Multi-color visible light communication (VLC) and wireless fidelity (WiFi) networks provide a promising solution for the indoor wireless communication, while the hybrid networks face the challenge of imbalanced access point (AP) load and resource allocation. A resource allocation method based on user service differentiation (RAMUSD) is proposed for multi-color VLC/WiFi hybrid networks. In our design, the user’s premium level is defined according to the user’s channel conditions and requested data rate. The heterogeneous network selects the service AP for the users according to its premium level, user with high premium level is served by one of VLC access points (APs), while user with low premium level is served by WiFi AP. Then, the average satisfaction is used as the load index to adjust the number of users served by the WiFi AP or the VLC AP to achieve load balance among APs. Furthermore, the RAMUSD uses the potential game theory to optimize user’s migration and resource allocation among APs for improving the load balancing index. In the potential game, user can improve its return value by changing access AP. So, it makes user who pursue more resources give up the congested APs. Simulation results show that the proposed RAMUSD can achieve better system throughput and user satisfaction than an enhanced proportional fairness algorithm based on evolutionary game theory (EPF-EGT).

IRS Empowered UAV Wireless Communication With Resource Allocation, Reflecting Design and Trajectory Optimization

As revolutionary technologies that can actively change the communication link signal, intelligent reflecting surface (IRS) and unmanned aerial vehicle (UAV) have emerged as reliable, economical and convenient wireless communication solutions for a variety of practical scenarios. Therefore, this paper focuses on an IRS empowered UAV downlink communication network, where the dynamic UAV establishes a cascade link via IRS to provide signal enhancement services for multiple users. Considering constraints of transmit power, flight speed and area at the UAV and the reflecting constraints at the IRS, the block coordinate descent (BCD) method based on resource allocation, reflecting design and trajectory optimization is adopted to maximize the sum-rate of all users. The proposed problem is converted by using quadratic transformation and Lagrangian dual transformation. Then applying for the approximate linear method and Iterative Rank Minimization (IRM) to optimize the transmit power of UAV and phase shift of IRS respectively. Since additional reflection propagation paths by IRS, the complexity of the channel model makes the trajectory design difficult. To tackle this problem, this paper proposes a UAV trajectory optimization method based on enhanced reinforcement learning with the fixed initial location and destination. In the end, the convergence of the proposed scheme is effectively verified by simulations. Moreover, abundant simulation comparisons between the proposed scheme and other benchmark schemes demonstrate the validity and high performance gains of the proposed algorithm.