Full-duplex Communication Research Articles

Real-time full-duplex transmission experiment for an air and underwater invisible light communication system

Specifications for highly secure and large-capacity optical transceivers are necessary when wireless communication is used over different transmission channels, such as underwater and air, in shallow sea areas. We evaluated the dynamic characteristics of bidirectional real-time transmission using an LED Backhaul that can generate and process direct current-added orthogonal frequency division multiplexing signals in the 850 nm band to demonstrate the feasibility of invisibility light communication. A composite channel that is 1.2 m in water and 10 m in the air was used as an optical radio channel. This experiment is the first report on real-time and 4 K video stream transmission for a line-of-sight full-duplex optical wireless communication in the invisible light band via heterogeneous transmission channels such as shallow water and air.

Optimizing the function of aircraft WiFi based on the Internet of Things

Abstract. This paper explores the potential of full-duplex wireless communication technology to mitigate interference in aircraft WiFi systems, thereby enhancing the internet access quality and passenger experience. The study focuses on the application of Internet of Things (IoT) technology to improve the resilience of aircraft WiFi systems against interference. Through a series of MATLAB simulations, the research demonstrates that full-duplex technology can effectively cancel out interference signals, leading to clearer and more stable communication quality. The results show that the combined signal, after cancellation, closely resembles the original communication signal, indicating a significant reduction in interference. Despite the promising results, the study acknowledges limitations such as idealized assumptions in the simulation, hardware and software constraints, and the lack of consideration for the complex electromagnetic environment encountered during actual flight operations. Future research should focus on developing more advanced interference detection and mitigation algorithms, and further investigation into the integration of full-duplex technology with existing aircraft WiFi systems, considering hardware constraints and environmental factors, is necessary to fully realize its potential in enhancing communication performance.

Research on the Progress of Modulation Technology and Data Transmission Technology in Underwater Wireless Optical Communication

Recently, as an efficient data transmission method, underwater wireless optical communication has become one of the key research topics in the fields of military communication and underwater surveillance. Modulation technology and technology in the transmission process play a key role in the UWOC system, which directly affects the performance, accuracy and safety of the system. The advanced modulation techniques from Intensity Modulation (IM), Pulse Modulation, Quadrature Amplitude Modulation (QAM), and Quadrature Phase Shift Keying (QPSK) to the combination of multiple modulation techniques, as well as the development process of modulation technology in optical encryption, are summarized in this paper. In terms of data transmission technology, the technological progress process from simplex to full-duplex communication is summarized. Finally, a reference solution is proposed to solve the challenges in realizing the underwater communication goals of long-distance, high-speed, low-bit error rate, and large-capacity underwater communication at the same time, and future development is prospected.

Full-duplex cooperative relaying systems for simultaneous wireless information and power transfer with non-orthogonal multiple access

In this research, we propose a system model based on cooperative non-orthogonal multiple access (NOMA) for simultaneous wireless information and power transfer (SWIPT) within a full-duplex (FD) communication framework. We investigate two protocols - time switching protocol (TSR) and power splitting protocol (PSR) - designed to accommodate delay-tolerant-transmission (DTT) as well as delay-limited-transmission (DLT), thereby improving data processing and energy harvesting (EH). We present explicit formulas for pivotal performance measures such as energy efficiency, ergodic rate, throughput, and outage probability. These performance measures are thoroughly evaluated in numerous specifications, encompassing inter-user separation, required spectral efficiency, EH efficiency, time and power splitting ratios in moderate-to-high signal-to-noise ratio scenarios. The results expose improved EH efficiency, hence meliorated transmission reliability. Importantly, NOMA in the proposed system model is proved to be considerably better than traditional orthogonal multiple access.

Decoupled Dipole Arrays Empowered by Invisible Complex Poles in Epsilon‐Near‐Zero Metamaterials

AbstractEvanescent waves, characterized by an exponential decay in propagation, have witnessed significant advancements in far‐field imaging and near‐field sensing applications. However, incoming evanescent waves can excite guided resonance inside a dielectric slab, resulting in a rapid growth of transmission coefficient toward infinity at the pole points. Such evanescent‐wave excited resonance benefits super‐resolution applications yet causes severe crosstalk in highly integrated multi‐channel devices. Here, the invisible complex poles are discovered in the transmission spectra of epsilon‐near‐zero (ENZ) metamaterials and demonstrate the striking suppression of near‐field crosstalk enabled by the anomalous transmission beyond the critical angle. Equipped with an ENZ metamaterial spacer, collinear dipole arrays exhibit 9.2 dB improvement in near‐field isolation among interior dipoles at a distance of less than one wavelength. Experimental measurements show negligible influence on the intrinsic impedance matching and radiation patterns of the dipole antennas. The discovered field divergence effect from the disappearance of real‐valued pole singularity in ENZ metamaterials offers an alternative solution for highly compact arrays in full duplex communication and multiple‐input multiple‐output technology.

Drone-based mobile full-duplex optical communication

Wireless optical communication plays a vital role in mobile communication networks, and both drones and vehicles are essential mobile communication nodes. Here, image identification technology, gimbal, and full-duplex optical communication systems are integrated to manage the challenging issues of light alignment and target tracking for mobile full-duplex optical communication under the transmission control protocol/internet protocol (TCP/IP) scheme. Both drones and vehicles are equipped with the proposed setup to realize full-duplex wireless optical data transmission at a communication rate of 2 Mbps in both air-to-ground and air-to-air scenarios. By further integrating wireless-fidelity (Wi-Fi) modules, drone-based mobile optical communication systems (MOCSs) can be interconnected with the network via the TCP/IP scheme, and real-time video transmission can be demonstrated. This work provides a feasible route toward a mobile optical communication network (MOCN) for diverse applications.

Mathematical analysis of busy tone in full-duplex optical MAC for hidden node mitigation

This article provides the mathematical analysis of carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol of IEEE 802.15.7 optical wireless communication (OWC). While the prior works have performed the OWC CSMA/CA mathematical analysis using the Markov models, deviation from the simulation results has been observed. We address this by improving the Markov model calculations, which display a mere 0.2% throughput deviation, nearly matching the simulation results. Furthermore, we work on the hidden node problem of the OWC networks. This problem is solved in literature by using various full-duplex communication methods, such as bi-directional data transmission and the busy tone signal; the latter is employed in our previous work on full-duplex optical MAC (FD-OMAC). These techniques increase the coverage area of the nodes by utilizing an access point (AP) as a relay node. However, the AP response is delayed by the processing time, causing an unexpected network behavior. The quantitative effect of this delay remains unexplored, which is critical for optimizing the OWC network. We bridge this gap by extending the proposed Markov analysis to model CSMA/CA and the aforementioned full-duplex techniques. This work equips readers with mathematical insights for future OWC MAC layer enhancements.

Dual-Band Passive Beam Steering Antenna Technologies for Satellite Communication and Modern Wireless Systems: A Review.

Efficient beam steerable high-gain antennas enable high-speed data rates over long-distance networks, including wireless backhaul, satellite communications (SATCOM), and SATCOM On-the-Move. These characteristics are essential for advancing contemporary wireless communication networks, particularly within 5G and beyond. Various beam steering solutions have been proposed in the literature, with passive beam steering mechanisms employing planar metasurfaces emerging as cost-effective, power-efficient, and compact options. These attributes make them well-suited for use in confined spaces, large-scale production and widespread distribution to meet the demands of the mass market. Utilizing a dual-band antenna terminal setup is often advantageous for full duplex communication in wireless systems. Therefore, this article presents a comprehensive review of the dual-band beam steering techniques for enabling full-duplex communication in modern wireless systems, highlighting their design methodologies, scanning mechanisms, physical characteristics, and constraints. Despite the advantages of planar metasurface-based beam steering solutions, the literature on dual-band beam steering antennas supporting full duplex communication is limited. This review article identifies research gaps and outlines future directions for developing economically feasible passive dual-band beam steering solutions for mass deployment.

Full-duplex dynamic TDMA scheme and clock synchronization and compensation method for the multi-user UWOC system.

In this Letter, we propose a full-duplex dynamic time division multiple access (FDD-TDMA) scheme for multi-user underwater wireless optical communication (UWOC). It supports full-duplex communication through wavelength division duplex (WDD) and enhances the system throughput using dynamic time resource allocation. Additionally, a clock synchronization and compensation method is proposed for precise clock synchronization without time-keeping. With the proposed FDD-TDMA scheme and the clock synchronization and compensation method, we establish a two-user UWOC system based on on-off keying (OOK) modulation. Experiments are conducted in a 10 m water pool environment. The experimental results show that the designed system can achieve a data rate of 25 Mbps without error codes and 40 Mbps with a bit error rate (BER) below the forward error correction (FEC) limit. The FDD-TDMA scheme notably improves the system throughput when communication demands among users are variable compared to the conventional time division multiple access (TDMA). Moreover, a reduction in phase deviations from microseconds to ten nanoseconds is achieved by the clock synchronization and compensation method.

Full-duplex two-way no-relay cross-media communication method based on acoustic wave conversion

Abstract Due to the difference in acoustic impedance between water and air, the water interface becomes a natural barrier. Underwater sound waves will bounce when they propagate to the water surface. Electromagnetic waves and light waves in the air will rapidly attenuate after passing through the water surface and going underwater, making it difficult to complete air-water cross-media information transmission. In this article, we first analyze the theoretical characteristics and vibration model of the water surface after medium collision, and develop a new full-duplex communication method across the air-ocean medium, which does not rely on relay equipment and only uses three transmission media in the air. Propagate signals in the sea channel physical field to achieve two-way communication, using the mutual conversion between laser, acoustic, and radio frequency signals to fill the gap in cross-media communication technology that can simultaneously achieve two-way, full-duplex and non-relay. It has been verified through experimental installations carried out in laboratory water tanks and large comprehensive anechoic pools that it is able to achieve full-duplex communication links across the air-sea surface, indicating that the combination of laser acousticization and radio frequency-acoustic wave conversion can be used across medium full-duplex wireless communication provides a feasible method for communication that breaks through the water interface.

Channel Estimation for Full-Duplex OFDM-Based Ambient Backscatter Communication Systems With I/Q Imbalance

Channel Estimation for Full-Duplex OFDM-Based Ambient Backscatter Communication Systems With I/Q Imbalance

Nonlinear Self-Interference Cancellation in Vehicle Networks for Full-Duplex Integrated Sensing and Communication

Nonlinear Self-Interference Cancellation in Vehicle Networks for Full-Duplex Integrated Sensing and Communication

An experimental study on beamforming architecture and full-duplex wireless across two operational outdoor massive MIMO networks

Full-duplex (FD) wireless communication refers to a communication system in which both ends of a wireless link transmit and receive data simultaneously in the same frequency band. One of the major challenges of FD communication is self-interference (SI), which refers to the interference caused by transmitting elements of a radio to its own receiving elements. Fully digital beamforming is a technique used to conduct beamforming and has been recently repurposed to also reduce SI. However, the cost of fully digital systems dramatically increases with the number of antennas, as each antenna requires an independent Tx-Rx RF chain. Hybrid beamforming systems use a much smaller number of RF chains to feed the same number of antennas, and hence can significantly reduce the deployment cost. In this paper, we aim to quantify the performance gap between these two radio architectures in terms of SI cancellation and system capacity in FD multi-user Multiple Input Multiple Output (MIMO) setups. We first obtained over-the-air channel measurement data on two outdoor massive MIMO deployments over the course of three months. We next study SoftNull and M-HBFD as two state-of-the-art transmit (Tx) beamforming based FD systems, and introduce two new joint transmit-receive (Tx-Rx) beamforming based FD systems named TR-FD2 and TR-HBFD for fully digital and hybrid radio architectures, respectively. We show that the hybrid beamforming systems can achieve 80%–99% of the fully digital systems capacity, depending on the number of users. Our results show that it is possible to get many benefits associated with fully digital massive MIMO systems with a hybrid beamforming architecture at a fraction of the cost.

Reinforcement learning-based automated modulation switching algorithm for an enhanced underwater acoustic communication

Acoustic communication is the preferred method for underwater communication due to its superior propagation characteristics, including longer range, lower attenuation, better penetration, and adaptability to water density. However, challenges like varying water depths, temperature gradients, noise, and multipath propagation require innovative solutions beyond fixed-data rate systems and single modulation schemes. To address these challenges, we propose a reinforcement learning (RL)-based automated modulation switching algorithm designed to enhance data transmission efficiency. This approach leverages the UNETStack software and the Frequency Hopping-Binary Frequency Shift Key (FH-BFSK) modulation, extending its capabilities by incorporating Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), and Orthogonal Frequency Division Multiplexing (OFDM) modulation techniques. We designed a cost-effective, software-controlled acoustic modem using commercial off-the-shelf (COTS) components, enabling full-duplex underwater communication. The RL algorithm utilizes a Q-matrix guided by a greedy policy to assess network conditions, such as data volume and data rates. It continuously monitors underwater environments to select the most suitable modulation scheme dynamically. Experimental validation demonstrates a 3.648 % improvement in Received Signal Strength Indicator (RSSI), a 32 % reduction in bit error rate at a constant 7 dB Signal-to-Noise Ratio (SNR), and a 5 % increase in utility at 10 dB SNR when using OFDM selected by the reinforcement learning algorithm, compared to FH-BFSK.

Design of a Novel RFID Reader for Oilwell Downhole Applications

RFID (Radio Frequency Identification), which transmits control data through electronic tags in a non-contact manner, provides a new approach for efficient and low-cost remote control of oil downhole tools. However, the interference of harsh downhole environments and the high-speed movement of tags seriously affect the performance of the current downhole reader. To effectively address this issue, in this study, a novel downhole RFID reader is presented. By introducing the half-duplex communication protocol to replace the current full-duplex communication protocol in the hardware circuits of the reader, its tag recognition ability can be improved. Then, the corresponding hardware circuits and software programs are designed. Furthermore, a sparse solenoid antenna is adopted to replace the traditional tightly wound solenoid antenna, which can provide a longer reading area range to cope with the high-moving tag, and its total length and spacing parameters between adjacent coils are designed in detail. The test results show that the proposed RFID reader based on a half-duplex communication protocol can communicate with tags normally, and its sparse solenoid antenna provides significantly more tag reading times than traditional tightly wound solenoid antennas under the same antenna inductance.

FPGA-based SPI serial communication

With advances in computer and IoT technology, the realization of the Internet of Everything is just around the corner. Synchronous serial bus communication with simple, high-speed interfaces and easy implementation will become a key player in the electronics industry. However, due to factors such as I/O resources, timing constraints, and register resources, general microcontrollers have various problems. The serial bus communication of I/O simulation has a low transmission rate and cannot achieve true full duplex communication. SPI is a standard for serial transmission introduced by Motorola in the United States. It is a high-speed, full-duplex, synchronous communication bus. Peripheral chips with SPI interface are abundant and widely used. This design uses Verilog HDL language to describe the function, based on the FPGA platform, verifies the SPI serial communication protocol, and realizes the serial communication between the sender and the receiver. SPI has important research significance for enhancing the stability of inter-device communication, improving communication speed and transmission security in the future.

Serial Peripheral Interface Conversion for Fast Data Transfer

The reason of this paper is to plan and mimic a Convention between the two broadly acknowledged serial communication conventions SPI and I2C. PI may be a serial transport and is exceptionally common within the inserted world. SPI bolsters full duplex communication with higher throughput than I2C. Many inserted frameworks have as it were SPI Interfaces, making them troublesome to associate with I2C peripheral gadgets. You'll adjust the associations, but the coming about framework isn't proficient. One of the most excellent ways to bargain with this issue is to form an SPI- to-I2C Interface and actualize it in FPGA. This paper clarifies approximately the communication between SPI and I2C, where it moreover amplifies up to USB communication. The transmission of information from MOSI and MISO utilizing SIPO, PIPO and at long last we will utilize FIFO to stack the information and check outcomes about in FPGA through recreation prepare. I2C, a serial transport designed by Philips, is utilized to communicate with low-speed peripherals. It employments two bidirectional open-drain lines: Serial Information (SDA) and Serial Clock (SCL). The master at first sends a begin bit, taken after by the 7-bit address of the slave it wishes to communicate with, which is at long last taken after by a single bit speaking to whether it wishes to type in (0) to or studied (1) from the slave. In case the slave exists on the transport, it'll react with an ACK bit (dynamic low for recognized) for that address. The master at that point proceeds in either transmit or get mode, and the slave proceeds in its complementary mode. Every data byte put on the SDA line has to be 8-bits long. At last, the recreation results are found in the test bench behavioral displaying in Simulator Window in Xilinx ISE Block of the respective test bench.

Full-Duplex Magnetic Induction Communication: Opportunities and Challenges

Full-Duplex Magnetic Induction Communication: Opportunities and Challenges

Reconfigurable Intelligent Surfaces Between the Reality and Imagination

One interesting idea that could improve wireless communication systems is reconfigurable intelligent surfaces or RIS. To control the spread of wireless signals, RIS uses a plethora of tiny, inexpensive, and customizable reflecting devices. Signal strength, energy consumption, spectrum efficiency, and adaptability to changes in the wireless environment can all be improved by altering the phase shift of the reflecting elements. This is how RIS works. 5G and beyond, the IoT, and smart cities are just a few of the many potential uses for RIS. More study is required before this technology can reach its full potential since it is still in its infancy. Still, RIS is going to be big in the next generation of wireless networks. A great deal of excitement has enveloped the whole 6G development industry. There has been no shortage of grandiose and frequently unfounded assertions that, in reality, the creation of a full-duplex 5G technology that can introduce new services is just around the corner, even though self-interference cancellation schemes for full-duplex communications and the difficulties of building full-duplex base stations have long been known.

Orthogonal waveform-based backscattering interference suppression technique for underwater optical wireless communication

The backscattering effects degrade the detection performance in a full-duplex underwater optical wireless communication (UOWC) system when the power of received backscattering interference is comparable to that of a target signal. In this paper, the orthogonal waveforms with the Hermite–Gaussian function and prolate spheroidal wave function are first introduced for a pulse position modulation based dynamic UOWC system to alleviate the backscattering effects. Then, a joint maximum likelihood detection scheme is proposed accordingly. Experimental results verify the superiority of the proposed method with orthogonal waveforms over the scheme without orthogonal pulse shaping in a dynamic underwater bubbly channel.