Coverage Probability Analysis for Full-Duplex Relay Aided Device-to-Device Communications Networks

The coverage probability of both the cellular users and the Device-to-Device(D2D) users are analyzed. We assume that the cellular users are able to communication with the Base Station(BS) either by relying on the assistance of Full-Duplex(FD) mode relays or via direct user-to-BS links with high-enough Signal-to-Interference-plus-Noise-Ratio(SINR). Note that the FD-mode devices are capable of simultaneously operating in two modes,i.e. the D2D mode and the cooperative relay mode,with the sum power consumption at these devices kept constant. The closedform expressions for coverage probability of both tier users are derived. After that,numerical analyses are provided,showing that the coverage probability of the both the cellular and the D2D users can be substantially influenced by a variety of parameters,including the power allocation factor of the relays,the density of users,and the self-interference imposed on the FD mode relays,etc. Furthermore,in the D2D enabled networks,it is shown that the FD relay aided transmission is beneficial to enhancing the coverage probability of the cellular users if the target SINR is lower than 5 d B.

Joint Spectrum Partition and Performance Analysis of Full-Duplex D2D Communications in Multi-Tier Wireless Networks

Full-duplex(FD)has been recognized as a promising technology for future 5G networks to improve the spectrum efficiency.However,the biggest practical impediments of realizing full-duplex communications are the presence of self-interference,especially in complex cellular networks.With the current development of self-interference cancellation techniques,full-duplex has been considered to be more suitable for device-to-device(D2D)and small cell communications which have small transmission range and low transmit power.In this paper,we consider the full-duplex D2D communications in multi-tier wireless networks and present an analytical model which jointly considers mode selection,resource allocation,and power control.Specifically,we consider a distance based mode selection scheme.The performance analysis of different D2D communications modes are performed based on stochastic geometry,and tractable analytical solutions are obtained.Then we investigate the optimal resource partitions between dedicated D2D mode and cellular mode.Numerical results validate the theoretical anlaysis and indicate that with appropriate proportions of users operated in different transmission modes and optimal partitioning of spectrum,the performance gain of FD-D2D communication can be achieved.

Energy-Efficient Full-Duplex UAV Relaying with Trajectory Optimization and Power Control in Maritime Communication Environments

This paper solves an energy-efficient optimization problem of a fixed-wing unmanned aerial vehicle(UAV) assisted full-duplex mobile relaying in maritime communication environments.Taking the speed and the acceleration of the UAV and the information-causality constraints into consideration,the energy-efficiency of the system under investigation is maximized by jointly optimizing the UAV’s trajectory and the individual transmit power levels of the source and the UAV relay nodes.The optimization problem is non-convex and thus cannot be solved directly.Therefore,it is decoupled into two subproblems.One sub-problem is for the transmit power control at the source and the UAV relay nodes,and the other aims at optimizing the UAV s flight trajectory.By using the Lagrangian dual and Dinkelbach methods,the two sub-problems are solved,leading to an iterative algorithm for the joint design of transmit power control and trajectory optimization.Computer simulations demonstrated that by conducting the proposed algorithm,the flight trajectory of the UAV and the individual transmit power levels of the nodes can be flexibly adjusted according to the system conditions,and the proposed algorithm can achieve signiflcantly higher energy efficiency as compared with the other benchmark schemes.

Tradeoffs in Covert Wireless Communication with a Controllable Full-Duplex Receiver

This paper investigates the tradeoff of the communication link and the eavesdropping link in covert communication in the presence of a full-duplex(FD)receiver.When a warden(Willie)attempts to detect the signal transmitted from a legitimate transmitter(Alice),the controllable FD receiver(Bob)can transmit with random power to impose interference uncertainty to Willie and force it to make an incorrect decision.To maximize the average transmission rate(ATR)of Alice-Bob and the average covert probability(ACP)for Willie,we propose a multi-objective optimization framework to optimize Bob’s power uncertainty range(PUR)and spatial position jointly,subject to the sufficient condition for covert communication and the none-deployed-zone(NDZ).Due to the presence of multiple optimization objectives and nonconvex constraints,the nondominated sorting genetic algorithm II(NSGA-II)is utilized to explore the Pareto front and to give a set of solutions that reflect tradeoffs between the two conflicting objectives.Simulation results reveal that the solutions determined by the NSGA-II have larger values for both ATR and ACP than the other two baselines.Simulations also show the positive effect of the width of the PUR of Bob on the Pareto front.

Duplexer Design for Full-Duplex Based Wireless Communications

The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.

Full-Duplex Cooperative Relaying with Non-Linear Energy Harvesting for Vehicular Communication

This paper analyses the performance of fullduplex(FD)dual-hop vehicular cooperative network with decode-and-forward(DF)protocol.At FD relay nodes,we examine the effects of non-linear hybrid power time splitting(PTS)based energy harvesting(EH).All three nodes—source(S),relay(R),and destination(D)are assumed to be moving vehicles.The expressions for the system's outage probability(OP)over double(cascaded)Rayleigh fading channels are derived.We also analyse the impact of residual self-interference(RSI)caused at FD relay on system's performance.We compare the performance of system with two relay selection techniques,namely,maximum channel gain-based(Max-G)relay selection and minimum RSI-based(Min-SI)relay selection.This paper considers the joint effect of time splitting ratio and self-interference cancellation(SIC)level to find the optimum EH duration.Additionally,the effect of time splitting ratio and average signal-to-noise ratio(SNR)on outage and throughput performance of the system are also investigated in this paper.The derived expressions are validated through Monte Carlo simulations.

A Novel Forwarding Method for Full-Duplex Two-Way Relay Networks

An estimate-and-forward(EF) scheme for single-input single-output(SISO) and multiple-input multiple-output(MIMO) full-duplex two-way relay networks is proposed and analyzed. The relay estimates the received signal from two terminal nodes by a minimum mean squared error(MMSE) estimation and forwards a scaled version of the MMSE estimate to the destination. The proposed EF outperforms conventional amplify-and-forward(AF) and decode-and-forward(DF) across all signal-to-noise ratio(SNR) region. Because its computational complexity is high for relays with a large number of antennas(large MIMO) and/or high order constellations, an approximate EF scheme, called list EF, are thus proposed to reduce the computational complexity. The proposed list EF computes a candidate list for the MMSE estimate by using a sphere decoder, and it approaches the performance of the exact EF relay at a negligible performance loss. The proposed forwarding approach also could be used to other relay networks, such as half-duplex, one-way or massive MIMO relay networks.

All-Digital Self-Interference Cancellation in Zero-IF Full-Duplex Transceivers

In this paper,a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear distortion signals falling in receiving band considered. A joint estimation algorithm is proposed for compensating the time delay and frequency offset taking into account the IQ amplitude and phase imbalances from mixers. The memory effect and nonlinear distortion are adaptively estimated by the de-correlated normalized least mean square(DNLMS) algorithm. Numerical simulation results demonstrate that the proposed self-interference cancellation scheme can efficiently compensate the self-interference and outperform the existing traditional solutions.

In Band Full Duplex (IBFD) Technology for Next Generation Wireless Networks: A Survey in Cellular Networks

Next-Generation(NextG)wireless communication networks with their widespread applications require high data rates,seamless connectivity and high quality of service(QoS).To cope up with an unprecedented rise of data hungry applications,users demand more spectral resources imposing a limitation on available wireless spectrum.One of the potential solutions to address the spectrum scarce issue is to incorporate in band full duplex(IBFD)or full duplex(FD)paradigm in next generation networks including 5G new radio(NR).Recently,FD has gained the research interest in cellular networks for its potential to double the wireless link capacity and enhancing spectral efficiency(SE).In half duplex(HD)cellular networks,base stations(BSs)can either perform uplink(UL)or downlink(DL)transmission at a particular time instant leading to reduced throughput levels.Due to the advancement in the self interference reduction(SIR)techniques,full duplex base stations(FD-BSs)can be employed to allow simultaneous UL and DL transmissions at the same time–frequency resources as compared to its HD counterpart.It ideally achieves twice the throughput without any additional complexity at user-equipment(UE).This paper covers a detailed survey on FD cellular networks.A series of SIR approaches,UE-UE mitigation techniques are summarized.Various existing MAC protocols and antenna architectures for FD cellular networks are outlined.An overview of security aspects for FD in cellular networks is also presented.Lastly,various open issues and possible research directions are brought up for FD cellular networks.

High Performance Speech Compression System

Since Pulse Code Modulation emerged in 1937, digitized speech has experienced rapid development due to its outstanding voice quality, reliability, robustness and security in communication. But how to reduce channel width without loss of speech quality remains a crucial problem in speech coding theory. A new full-duplex digital speech communication system based on the Vocoder of AMBE-1000(TM) and microcontroller ATMEL 89C51 is introduced. It shows higher voice quality than current mobile phone system with only a quarter of channel width needed for the latter. The prospective areas in which the system can be applied include satellite communication, IP Phone, virtual meeting and the most important, defence industry.

Recent Advances of Simultaneous Wireless Information and Power Transfer in Cellular Networks

As a promising solution to alleviating the energy bottleneck in wireless devices with limited battery capacity,simultaneous wireless information and power transfer(SWIPT)techniques have been widely researched in cellular networks.To further improve the spectral and energy efficiency of wireless information and power transfer,the combination of SWIPT and new techniques in cellular networks has drawn much attention recently.In this paper,we comprehensively survey the key techniques for SWIPT,the combination of SWIPT and new techniques in cellular networks,challenges and open issues.The key techniques for SWIPT including traditional power splitting,time switching,etc.,and joint receiving and transmitting techniques such as eigenchannels and mixed signals are provided in detail.Furthermore,the applications of SWIPT to recent techniques such as SWIPT-assisted non-orthogonal multiple access,SWIPT-assisted device-to-device communication,and SWIPT-assisted full-duplex communication,are comprehensively summarized in this paper.The potential open issues including the management of dynamic harvested energy,trading between wireless power transfer and traffic offloading,and effects of the mode switching at energy harvesting devices,are outlined as well.

A Wire-Line Secure Communication System Based on CCFD Self-Interference Cancellation

This paper presents a design scheme of wire-line telephone system using self-interference(SI)cancellation technology in co-frequency co-time full-duplex(CCFD)system to realize absolute secure communication at the physical layer.This scheme can hide the target signal by skillfully releasing the high-power artificial noise to the whole link at the receiving node,and then make use of the receiver’s knowledge of the SI signal to achieve high dB SI cancellation with the help of analog domain SI cancellation technology in CCFD domain,so that the signal-to-noise ratio(SNR)received by the eavesdropper at any position of the link is far lower than that of the legitimate receiver,so as to realize the absolutely secure communication in the sense of Wyner principle.This paper not only puts forward the specific design scheme of absolutely secure communication telephone,but also analyzes the calculation of security capacity under different eavesdropping positions,different SI cancellation capability and different system parameters according to Shannon theory.

Design of Wireless Optical Access System using LED

This paper develops a prototype to demonstrate a full-duplex wireless visible light communication (VLC) system based on Universal Serial Bus (USB) port. Combing with a USB 2.0 port on one board, it can achieve up to 2 Mbps bit rates error free, which is mainly limited to the USB bridge circuit, between two computers for data transmission, such as text, audio and video. Hyper Terminal and self-written software are used to allow setting the transmission data rate, control bits, check bits and achieve real-time transmission between any two mobile devices with a USB port. The work is based on the research of VLC local access network. This paper also shows the experimental results and the relationship between system transmission eye diagram and bit rate.

RF self-interference cancellation by using photonic technology [Invited]

Radio frequency(RF) self-interference is a key issue for the application of in-band full-duplex communication in beyond fifth generation and sixth generation communications.Compared with electronic technology, photonic technology has the advantages of wide bandwidth and high tuning precision, exhibiting great potential to realize high interference cancellation depth over broad band.In this paper, a comprehensive overview of photonic enabled RF self-interference cancellation(SIC)is presented.The operation principle of photonic RF SIC is introduced, and the advances in implementing photonic RF SIC according to the realization mechanism of phase reversal are summarized.For further realistic applications, the multipath RF SIC and the integrated photonic RF SIC are also surveyed.Finally, the challenges and opportunities of photonic RF SIC technology are discussed.