Full-duplex Channel Research Articles

Light Weight Concurrent Scheduling of Mobile Sink routing protocol towards Minimization of Propagation Delay against Spatial and Temporal Uncertainties of Cluster based Wireless Sensor Network

Wireless Sensor Network highly exposed to certain security attacks due to various uncertainties of the network which lead to node compromise. Hence considerable attention has been made by researcher during scheduling of the mobile sink to data collection of sensed information from the sensor nodes. Many secure data aggregation mechanism has been proposed to withstand the network against these kind of attack. Despite of many advantageous, those architectures will lead to several limitations such as large propagation delay and high energy consumption and spatial and temporal uncertainties. In order to mitigate those challenges, Light Weight Concurrent Scheduling of Mobile Sink routing protocol towards Minimization of Propagation Delay against Spatial and Temporal Uncertainties of Wireless Sensor Network is designed. It should be capable achieving energy efficiency and collision avoidance due to uncertainty in transmission and reception. Proposed model eliminates the packet collision and poor channel utilization challenges. Initially, node is partitioned and cluster head is selected based on the highest energy density of the node in the particular location. Employing Full duplex channel easily examines the spatial and temporal characteristic of the node through utilization cache information of routing table. It further helps to build the light weight scheme with behavioral strategies of the nodes for secure propagation of the sensed data to the mobile sink. Light weight scheme deployed in mobile sinks estimate the node trustworthiness and simultaneously collects the secure aggregated data packets of the sensor node through cluster head against dynamic time slots concurrently .Comparing with traditional secure routing architecture, simulation results demonstrates that proposed architecture can reduce the propagation delay against various uncertainties and maximizes the life time of the network on increasing the networking performances with respect to packet delivery ratio, throughput and propagation delay. Finally proposed model obtains the cooperative communication of sensor node information to the base station through mobile sink on heterogeneous wireless sensor network environment. DOI: https://doi.org/10.52783/pst.387

Overview of use cases in single channel full duplex techniques for satellite communication

Overview of use cases in single channel full duplex techniques for satellite communication

A multi-user cognitive radio full-duplex channel under imperfect spectrum sensing: Achievable rates and energy efficiency

In this work, the achievable rates and energy efficiency of a multi-user cognitive radio (CR) uplink channel with full-duplex (FD) are studied. For this multi-user CR channel, secondary users can work in FD mode to simultaneously transmit and listen to the channel. We consider a realistic scenario in which both FD operation and spectrum sensing are imperfect. At first, we examine the sensing performance and the rate region through the evaluation of the probability of miss-detection and the probability of false alarm when the primary user (PU) activity is assumed to be non-time-slotted. Due to an imperfect sensing operation, the cognitive radio channel is modeled as a non-Gaussian channel impacted by a Gaussian-mixture (GM) noise plus PU interference. Under this practical assumption, it is not possible to calculate the achievable rates and the rate region directly. Instead, we derive simple approximations of these metrics which can be easily calculated with arbitrarily small errors. In the second part of the paper, we further evaluate the derivatives of these achievable rates at low-power regimes. This calculation helps us evaluate the energy efficiency and obtain the minimum energy per bit Eb/N0min when Gaussian and discrete input signals are used.

An Adaptive-Iterative Nonlinear Interference Cancellation in Time-Varying Full-Duplex Channels

In this paper, first, the sensitivity of traditional Full-Duplex (FD) communication systems to time variation in the self-interference (SI) channel is demonstrated via performance analysis. It is seen that conventional schemes are not capable of providing efficient operation regarding practical concerns such as spectral efficiency, SI channel aging and learning accuracy, and the contamination of signal-of-interest (SoI). Then, in regard to the aforementioned concerns, a practical FD operation together with a novel iterative SoI-contamination-aware digital SI cancellation (DSIC) algorithm that relieves the sensitivity against time variation considerably is proposed. The proposed scheme, namely <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Turbo</i> DSIC, is practical in terms of training and computational complexity thanks to its two-stage structure such that complex nonlinear parameter learning (NPL) is conducted very rarely in the first stage, and linear processing is performed adaptively at symbol-rate in the second stage, where SoI is iteratively estimated at each data block and eliminated from the received signal to improve SI channel estimation accuracy. Finally, the performance of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Turbo</i> DSIC, under hardware impairments and time-varying (TV) propagation, is evaluated via both computer simulation environment and actual experimental hardware setup in terms of bit error rate (BER) and achievable information rate (AIR) metrics.

Ray-Tracing Simulation and Verification of Full-Duplex Self-Interference Channels in an Urban Scenario

Compared with the half-duplex (HD), co-time co-frequency full-duplex (CCFD) technology can effectively improve spectrum utilization. Self-interference (SI) is one of the major factors limiting full-duplex (FD) performance. In this letter, we build the same scattering environment as the field measurement campaign, and simulate the FDSI and the conventional base station-to-base station (B2B) channels using ray-tracing technology. We simulate all the multi-path components (MPCs) and observe the power delay profiles (PDPs), received power, and delay spreads (DS) by changing the angular gap between and the height of the transmitting (Tx) and the receiving (Rx) antennas. The parameters and profiles of the simulated SI channel are consistent with and thus verify the measurement results. To further compare the FD channels and the conventional base station-to-user equipment (B2U) channel, we also compare the measured and simulated SI channels with the 3GPP channel model. It is interesting to find out that the channel characteristics are quite similar in the same scenario.

Fiber-Extended Copper Line Architecture With End-to-End Data Transmission and Link Monitoring

We demonstrate a prototype hybrid, full duplex fiber-extended copper line with frequency-reusability and simultaneous fiber and copper line monitoring. The link architecture is composed of three main units: a central office; a remote-node copper to fiber converter (CuFiC); and a radio head. A fiber optical link connects the central office to the remote node, while the remote node is connected to the radio head by a copper line. Even though the prototype is built with two full duplex channels, more channels can be supported by the architecture, and an optical feedforward linearization scheme for the transmitter is demonstrated for that purpose. In-service simultaneous multi-copper and fiber monitoring is possible with the right choice of frequency bands, a result backed by the Error Vector Magnitude measurement of data channels in simultaneous coexistence with monitoring channels. A frequency multiplication unit, built into both the transmitter and the remote node, allows for a single seed tone to generate all the sub-carrier multiplexed channels for up and downstream in both the fiber and in the copper links without the need of local oscillators. This not only simplifies the architecture, but also allows for optimal homodyne up- /down-conversion. The demonstrated prototype figures as a potential candidate for interfacing fiber to the home and fiber to the building (FTTH/FTTB) links with legacy copper infrastructure currently allowing for: up to eight 20MHz LTE 64QAM channels to be subcarrier-multiplexed onto a single optical carrier and seemlessly demultiplexed into individual copper channels, backed by a ≤8% EVM measured at the radio head; concurrent 7dB dynamic range 10 meter spatial resolution intermediate-haul fiber monitoring (up to 15 km) as well as copper line monitoring both available at the central office. The next steps beyond the presented proof of concept include simultaneous bi-directional transmission among multiple receivers, automated feed-forward linearization, and the study of factors that may limit the achievable dynamic range.

Circular and Dual Polarized Antenna for Self-Interference Cancellation in the Next Generation of Mobile Communication Networks

The interference phenomena is actually appeared in all current wireless communication systems. This problem has different forms and impacts the performance of any wireless system. At the present time, a new technology, that is called fifth generation (5G), of mobile communications knocks the doors to be commercial within few days. Conventional wireless communication systems use two separate channels, one channel to transmit and another to receive. Achieving single channel full duplex (FD) is one of the key challenges for 5G implementation. Single channel FD provides the capability of sending and receiving concurrently over the same channel, along with assuring efficient utilization of the available spectrum. With this newest technology, another sort of interference will be generated which is called self–interference (SI). SI cancellation techniques represent an awesome solution for the development of next generation. These techniques have two types: passive and active cancellation. Antenna cancellation approach can be characterized as a passive cancellation. In our proposed work, antenna with two feedings is employed as a cancellation procedure. A patch antenna is simulated and tested for two resonance frequencies, 2.45GHz and 28.0GHz. Both frequencies are candidates of frequency channel proposed by ITU for the fifth generation of mobile networks. Finally, the complete design and simulation of dual polarized, with series-fed 3 by 3 patch array on 3.3GHz, is provided.

Method for constructing distributed system components for calculating the stationary mode of an electronic schematic representation of microservices with a full-duplex communication channel

The joint use of a microservice architecture and a full-duplex WebSocket data transfer protocol for building components of a circuit design automation system is considered. Comparison of the organization of API based on the REST approach and using the WebSocket technology is made. The technique of horizontal scaling in systems with microservice architecture and full-duplex communication channels is determined. The advantages of using the WebSocket protocol for the interaction of distributed system components, in particular, with client PWA (Progressive Web Apps) applications, are given. The technique of creating a software implementation of the client and server components based on the full-duplex WebSocket protocol is considered. The technique of mathematical description of multi-pole components is considered. An algorithm for solving the problem of modeling a stationary mode of nonlinear circuits is described.

Dual Feeding Antenna for Performance Enhancement of Next Generation of Mobile Networks against Self Interference

Actually, the interference phenomena appear in all current wireless communication systems. Generally, conventional wireless communication systems use two separate channels; one of them for transmitting and the other one for receiving. Achieving single channel full duplex (FD) represents one of the key challenges for the implementation of 5G. Single channel FD permits the capability of wireless communication system to transmit and get concurrently on the identical channel, as well as the assurance of an efficient utilization of the current spectrum. With this newest technology, another sort of interference, which is called self–interference, will be generated. Therefore, self–interference cancellation strategies have an awesome solution for the development of the next generation. Passive and active cancellation techniques can be used to remedy such type of interference. In this regard, a dual feeding antenna approach is regarded as passive cancellation. This paper is concerned with this type of self-interference cancellation. A patch antenna is simulated and tested for two resonance frequencies; 2.45 and 28 GHz. Both of these frequencies are frequency channel candidates proposed by international telecommunication union (ITU) for the fifth generation of mobile networks.

Classes of Full-Duplex Channels With Capacity Achieved Without Adaptation

Full-duplex communication allows a terminal to transmit and receive signals simultaneously, and hence, it is helpful in general to adapt transmissions to received signals. However, this often requires unaffordable complexity. This work focuses on simple non-adaptive transmission, and provides two classes of channels for which Shannon's information capacity regions are achieved without adaptation. The first is the injective semi-deterministic two-way channel that includes additive channels with various types of noises modeling wireless, coaxial cable, and other settings. The other is the Poisson two-way channel, for which we show that non-adaptive transmission is asymptotically optimal in the high dark current regime.

Co‐polarized monostatic antenna with high Tx–Rx isolation for 2.4 GHz single channel full duplex applications

AbstractThis article presents a linear co‐polarized (same polarization for transmit and receive modes), proximity coupled monostatic patch antenna with high port to port RF isolation for 2.4 GHz single channel full duplex (SCFD) wireless applications. The presented proximity coupled monostatic patch antenna deploys differential feeding for receive (Rx) mode to significantly suppress RF leakage from transmit (Tx) port and external single‐tap self‐interference cancellation (SIC) circuit provides additional interport isolation. The measurements for implemented prototype of antenna in lab environment provide around 50 dB Tx–Rx isolation for 50 MHz bandwidth in addition to better than 75 dB peak isolation. Moreover, the deployed single‐tap RF SIC circuit can be used to suppress SI resulted from environmental reflections and 50 MHz SIC bandwidth with 50 dB isolation can be tuned within antenna's 10 dB return loss impedance bandwidth of 150 MHz.

Quality-Driven Resource Allocation for Full-Duplex Delay-Constrained Wireless Video Transmissions

In this paper, wireless video transmission over full-duplex channels under total bandwidth and minimum required quality constraints is studied. In order to provide the desired performance levels to the end-users in real-time video transmissions, quality of service requirements such as statistical delay constraints are also considered. Effective capacity is used as the throughput metric in the presence of such statistical delay constraints since deterministic delay bounds are difficult to guarantee due to the time-varying nature of wireless fading channels. A communication scenario with multiple pairs of users in which different users have different delay requirements is addressed. Following characterizations from the rate-distortion theory, a logarithmic model of the quality-rate relation is used for predicting the quality of the reconstructed video in terms of the peak signal-to-noise ratio at the receiver side. Since the optimization problem is not concave or convex, the optimal bandwidth and power allocation policies that maximize the weighted sum video quality subject to total bandwidth, maximum transmission power level and minimum required quality constraints are derived by using monotonic optimization theory.

Mixed Nash Equilibria for In-Band Full-Duplex Networks

This letter offers the first characterization of mixed Nash equilibria (MNE) for a wireless system with full-duplex (FD) capable terminals and slotted Aloha channel access. Focusing on a simple topology, we prove that MNE exist only if proportionality, driven by the accuracy of self-interference cancellation, is granted between the cost undergone for FD and half-duplex operations. The analysis shows how a proper selection of costs allows MNE that are also optimal from a network viewpoint in terms of aggregate throughput. The sensitivity of system performance to costs is tackled considering the price of anarchy.

Dual-Band Full-Duplex Tx/Rx Antennas for Vehicular Communications

This paper proposes a novel dual-band full-duplex antenna/array for intelligent transport systems applications. Different from traditional single-port single-band antennas, the two ports of the antenna are highly isolated and designed to operate at different frequency bands simultaneously. Such a property could support the full-duplex operation-mode, which significantly simplifies the complexity of the RF frontend subsystem. The other contribution of this work is that multiple functions such as filtering, duplexing, and radiation are combined into one single device, resulting in a simplified RF frontend. This co-design multifunctional device could also remove the separate filters, duplexers, and interfaces between them, resulting in the reduction of the size, weight, and cost. In addition, cross-coupling is investigated and employed to generate additional transmission zeros so as to improve the channel isolation and out-of-band interference. To verify the concept, an antenna element and two 2 × 2 arrays at C-band are designed, prototyped, and tested. All the measurements agree well with the simulations, showing two full-duplex channels of 4.58–4.83 GHz and 5.86–6.2 GHz for transmitting and receiving, respectively. The proposed antennas also exhibit excellent performance in terms of channel isolations, frequency selectivity, out-of-band rejections, and gains.

Full-duplex radio-over-fiber system with tunable millimeter-wave signal generation and wavelength reuse for upstream signal.

A full-duplex radio-over-fiber system is proposed, which provides both the generation of a millimeter-wave (mm-wave) signal with tunable frequency multiplication factors (FMFs) and wavelength reuse for uplink data. A dual-driving Mach-Zehnder modulator and a phase modulator are cascaded to form an optical frequency comb. An acousto-optic tunable filter based on a uniform fiber Bragg grating (FBG-AOTF) is employed to select three target optical sidebands. Two symmetrical sidebands are chosen to generate mm waves with tunable FMFs up to 16, which can be adjusted by changing the frequency of the applied acoustic wave. The optical carrier is reused at the base station for uplink connection. FBG-AOTFs driven by two acoustic wave signals are experimentally fabricated and further applied in the proposed scheme. Results of the research indicate that the 2-Gbit/s data can be successfully transmitted over a 25-km single-mode fiber for bidirectional full-duplex channels with power penalty of less than 2.6 dB. The feasibility of the proposed scheme is verified by detailed simulations and partial experiments.

Optimal Training-Based Scheme for MIMO Full-Duplex Wireless Links

In a multiple-input-multiple-output (MIMO) full-duplex (FD) wireless link, training-based schemes are the most effective with digital self-interference (SI) cancellation methods after antenna and analog SI cancellations, and they help receiver to know responses of both residual SI channel for digital cancellation and transmission channel for demodulation. In this situation, the open issue is that how much training is needed in MIMO FD wireless links-too little training will cause the imperfect digital SI cancellations and the transmission channels are also improperly learned, too much training and the links have no time left for the data transmission before the fading channel changes. We compute a capacity lower bound of a MIMO FD channel that is learned at the receiver by training without any feedbacks, and maximize the bound as a function of the received signal-to-noise ratio $\rho $ , fading coherence time $T$ , and numbers of link antennas $M$ , $N$ . When training power is equal to data power, numerical results show that the optimal number of training symbols $T_{o}$ is $T_{o}\geq 2\mathrm {max}(M,N)$ if $T \gg \mathrm {max}(M,N)$ under appropriate $\rho $ . Conversely, if $T\approx 2\max (M,N)$ , $T_{o} .

Signaling Design of Two-Way MIMO Full-Duplex Channel: Optimality Under Imperfect Transmit Front-End Chain

We derive the optimal signaling for a multiple input multiple output (MIMO) full-duplex (FD) two-way channel under imperfect transmit front-end chains. We characterize two-way rates of the channel by using a game-theoretical approach, where we focus on the Pareto boundary of the achievable rate region and the Nash equilibrium (NE). For a MIMO FD channel, the Pareto boundary achieves the global optimality. However, deriving the Pareto boundary amounts to solving a family of centralized non-convex problems. By introducing auxiliary variables, we decouple and convert the Pareto boundary into a family of convex problems, which enables us to obtain the Pareto boundary with low computational complexity. In a MISO FD two-way channel, we further present a closed-form expression for the Pareto-optimal signaling. In our numerical examples, we quantify gains in the achievable rates of the Pareto-optimal signaling over the zero-forcing beamforming and NE. For a distributed MIMO FD channel, we establish the existence of NE and present a condition for the uniqueness of NE. We then propose an iterative water-filling algorithm, which is capable of reaching the NE. Through simulations, the threshold of the self-interference level is found below which the FD NE outperforms the half-duplex TDMA.

Resource Allocation and Rate Gains in Practical Full-Duplex Systems

Full-duplex communication has the potential to substantially increase the throughput in wireless networks. However, the benefits of full-duplex are still not well understood. In this paper, we characterize the full-duplex rate gains in both single-channel and multi-channel use cases. For the single-channel case, we quantify the rate gain as a function of the remaining self-interference and SNR values. We also provide a sufficient condition under which the sum of uplink and downlink rates on a full-duplex channel is concave in the transmission power levels. Building on these results, we consider the multi-channel case. For that case, we introduce a new realistic model of a small form-factor (e.g., smartphone) full-duplex receiver and demonstrate its accuracy via measurements. We study the problem of jointly allocating power levels to different channels and selecting the frequency of maximum self-interference suppression, where the objective is maximizing the sum of the rates over uplink and downlink OFDM channels. We develop a polynomial time algorithm which is nearly optimal in practice under very mild restrictions. To reduce the running time, we develop an efficient nearly-optimal algorithm under the high SINR approximation. Finally, we demonstrate via numerical evaluations the capacity gains in the different use cases and obtain insights into the impact of the remaining self-interference and wireless channel states on the performance.

Average Rate Analysis for the Full-Duplex MISO Interference Channel

The achievable average rate of a full-duplex (FD) multiple-input-single-output interference channel with linear transceiver structures is analyzed. The impact of transmit front-end noise is included in the analysis. Both cooperative and non-cooperative strategies for the FD interference channel are considered and the closed-form expressions are derived for the achievable average rate of each strategy.

전이중 통신 방식을 사용하는 무선랜을 위한 간섭 제거 기법

In this paper, we employ the single channel full duplex radio for wireless local area network (WLAN) systems, and design digital interference cancellers using adaptive signal processing. When the full duplex scheme is used for WLAN systems with multiple transmit and receive antennas, some interference is caused through the feedback of transmit signals from multiple antennas. To remove the feedback interference, we derive the least mean square (LMS), normalized LMS (NLMS), and recursive least squares (RLS) algorithms based on adaptive signal processing techniques. In addition, we analyze the theoretical convergence of the proposed LMS and RLS methods. The channel capacity of full duplex radios increases by two times than that of half duplex radios, when the packet error rate (PER) performances for the two systems are identical. Through numerical simulations in WLAN systems, it is shown that the full duplex method with the proposed interference cancellers has a similar PER performance with the conventional half duplex transmission scheme.