Full Duplex Research Articles

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.

On performance of a full duplex SWIPT enabled cooperative NOMA network

On performance of a full duplex SWIPT enabled cooperative NOMA network

Joint Beamforming and Phase Shifts Design for RIS-Aided Multi-User Full-Duplex Systems in Smart Cities.

Full-duplex (FD) and reconfigurable intelligent surface (RIS) are potential technologies for achieving wireless communication effectively. Therefore, in theory, the RIS-aided FD system is supposed to enhance spectral efficiency significantly for the ubiquitous Internet of Things devices in smart cities. However, this technology additionally induces the loop-interference (LI) of RIS on the residual self-interference (SI) of the FD base station, especially in complicated urban outdoor environments, which will somewhat counterbalance the performance benefit. Inspired by this, we first establish an objective and constraints considering the residual SI and LI in two typical urban outdoor scenarios. Then, we decompose the original problem into two subproblems according to the variable types and jointly design the beamforming matrices and phase shifts vector methods. Specifically, we propose a successive convex approximation algorithm and a soft actor-critic deep reinforcement learning-related scheme to solve the subproblems alternately. To prove the effectiveness of our proposal, we introduce benchmarks of RIS phase shifts design for comparison. The simulation results show that the performance of the low-complexity proposed algorithm is only slightly lower than the exhaustive search method and outperforms the fixed-point iteration scheme. Moreover, the proposal in scenario two is more outstanding, demonstrating the application predominance in urban outdoor environments.

Outage and throughput performance analysis of smart UAV‐assisted full‐duplex NOMA‐based energy harvesting cognitive radio networks

SummaryIn this paper, the throughput and outage performance for an unmanned aerial vehicle (UAV)‐assisted non‐orthogonal multiple access (NOMA)‐based hybrid cognitive radio (CR) network are examined under m‐Nakagami fading channel. To be more specific, a secondary source transmitter ( ) broadcasts a NOMA‐enabled mixed signal to secondary destinations via UAV relay, which operates in full‐duplex (FD) mode and employs decode‐and‐forward protocol. In our approach, an energy harvesting (EH) circuit is employed at both and UAV to harvest energy from the PU radio frequency (RF) signals. These secondary transmitters are also incorporated with energy detector (ED) circuit as well, which detects the activity of the primary user (PU). The status of PU to be busy or idle is confirmed on the basis of the energy detector's results. In turn, this drives and UAV to switch between underlay and overlay protocols in an adaptive manner to increase spectrum efficiency (SE). The closed form mathematical expressions of the secondary outage probability for NOMA‐based UAV equipped CR networks under imperfect successive interference cancellation (i‐SIC) conditions have been evaluated. The administration of the power allocation policy at the and UAV is assessed while maintaining the PU quality of service (QoS). Finally, MATLAB simulation testbed has been used to verify all the analytical closed form expressions.

Performance analysis and optimization of frequency division duplex based virtual full-duplex communication systems

Virtual full-duplex (VFD) communication systems have become smart alternative over residual self-interference (RSI) affected full-duplex (FD) systems and thus has drawn significant research attention in the recent years. However, in comparison to FD, the VFD system models studied in the literature are based on successive relaying (SR) that require an extra time phase and a double number of relays for each destination user. Thus, we propose a novel frequency division duplex (FDD) based VFD (FDD-VFD) system model that can not only match FD in terms of resource utilization but also outperform both SR-VFD and FD. We consider two practical scenarios of absence of inter relay interference (A-IRI) and presence of IRI (P-IRI). We analyze the outage probability and ergodic rate performance metrics and present their analytical expressions in closed-form over Nakagami-m fading channels. Next, to minimize the effect of inter-relay interference in P-IRI scenario, we investigate optimization problems of minimizing the system outage probability and maximizing the ergodic sum rate for jointly allocating transmit power of the relays. We utilize particle swarm optimization algorithm and deep learning architecture to solve the formulated problems. Extensive evaluations are carried out over different system parameters to prove the efficacy of proposed FDD scheme and obtain key inferences.

Energy optimization for full-duplex wireless-powered IoT networks using rotary-wing UAV with multiple antennas

In this paper, we propose a novel design for the rotary-wing unmanned aerial vehicle (UAV)-enabled full-duplex (FD) wireless-powered Internet of Things (IoT) networks. In this network, the UAV is equipped with an antenna array, and the K IoT sensors, which are distributed randomly, use single-antenna to communicate. By sending the energy, the UAV as a hybrid access point, charges the sensors and collects information from them. Then, to manage the time and optimize the energy, the sensors are divided into N groups, so that the UAV equipped with multi-input multi-output (MIMO) technology can serve the sensors in a group, during the total time T. We provide a simple implementation of the wireless power transfer protocol in the sensors by using the time division multiple access (TDMA) scheme to receive information from the users. In other words, the sensors of each group receive energy from the UAV, when it hovers over the sensors of the previous group, and also when the UAV flies over the previous group to the current group. The sensors of each group send their information to the UAV, when the UAV is hovering over their group. Under these assumptions, we formulate two optimization problems: a sum throughput maximization problem, and a total time minimization problem. Numerical results show that our proposed optimal network provides better performance than the existing networks. In fact, our novel design can serve more sensors at the cost of using more antennas compared to that of the conventional networks.

OSAT Production Testing of 5G, Power Discretes & 3D packaged ICs

The presentation will be segmented into three. OSAT production testing challenges of three vital product families that are important to our semiconductor industry will be showcased in each segment. The first segment will describe the products and impacts to RF production testing of both Sub-8GHz carrier frequency range and the mmWave frequency range of operation. The second segment will explore emerging MOSFET technologies that enable faster switching rates and higher voltage and current topologies. The third segment will describe the challenges of production test content for 3D-stacked advanced packages. 5G RF has enabled mmWave carrier frequencies, small cell deployment, massive MIMO (Multiple In, Multiple Out), beam forming, and full duplex wireless transmission and reception operations. These features require new production test methodologies. There is an astronomical rise in battery powered applications like toys, consumer goods, automotive and trains. Power path turn on/off with MOSFETs is in the critical path. The technology has advanced from the traditional Si to GaN and SiC based products that have a smaller size and allow for higher application efficiencies. Test specifications and limits are improving and production testing methods are evolving to account for these changes. Advanced packaging has enabled the path to integrate chiplets within a single package. Heterogeneous Integration (HI) is a powerful design innovation that allows tighter integration and, in some cases, improved signal and power performance at the system level. Production test methodologies are being streamlined to make test a competitive advantage for our customers.

On the block error rate performance of cooperative non‐orthogonal multiple access short‐packet communications with full‐duplex relay and partial relay selection

AbstractIn this paper, we mathematically investigate a downlink non‐orthogonal multiple access (NOMA) system for short‐packet communications (SPC) in which the near users are used as full‐duplex (FD) relays to forward intended signals from the source to a far user. In addition, partial relay selection is employed to enhance the performance of the FD relays under the impact of imperfect interference cancellation. At the far user, selection combining (SC) or maximal ratio combining (MRC) is employed to combine the signals received from the source and the selected FD relay. The analytical expressions for the average block error rate (BLER) of two users over flat Rayleigh fading channels are derived. Furthermore, closed‐form asymptotic expressions of the average BLERs at the near and far users in high signal‐to‐noise ratio (SNR) regimes are obtained. The numerical results show that the analytical BLERs of the near user and far user closely match the simulation results.

Joint Power Control and Resource Allocation for Optimizing the D2D User Performance of Full-Duplex D2D Underlying Cellular Networks

D2D communication is a promising technology for enhancing spectral efficiency (SE) in cellular networks, and full-duplex (FD) has the potential to double SE. Due to D2D’s short-distance communication and low transmittance power, it is natural to integrate FD into D2D, creating FD-D2D to underlay a cellular network to further improve SE. However, the residual self-interference (RSI) resulting from FD-D2D and interference arising from spectrum sharing between D2D users (DUs) and cellular users (CUs) can restrict D2D link performance. Therefore, we propose an FD-D2D underlying cellular system in which DUs jointly share uplink and downlink spectral resources with CUs. Moreover, we present two algorithms to enhance the performance experience of DUs while improving the system’s SE. For the first algorithm, we tackle an optimization problem aimed at maximizing the sum rate of FD-DUs in the system while adhering to transmittance power constraints. This problem is formulated as a mixed-integer nonlinear programming problem (MINLP), known for its mathematical complexity and NP-hard nature. In order to address this MINLP, our first algorithm decomposes it into two subproblems: power control and spectral resource allocation. The power control aspect is treated as a nonlinear problem, which we solve through one-dimensional searching. Meanwhile, spectral resource allocation is achieved using the Kuhn–Munkres algorithm, determining the pairing of CUs and DUs sharing the same spectrum. As for the second algorithm, our objective is to enhance the individual performance of FD-DUs by maximizing the minimum rate among them, ensuring more uniform rate performance across all FD-DUs. In order to solve this optimization problem, we propose a novel spectral resource allocation algorithm based on bisection searching and the Kuhn–Munkres algorithm, whereas the power control aspect remains the same as in the first algorithm. The numerical results demonstrate that our proposed algorithm effectively enhances the performance of DUs in an FD-D2D underlying cellular network when compared to the sum rate maximization design.

Pelvic escape points: Bottom- up is the way to go!

Varicose veins (VVs) of pelvic origin are one of the clinical presentations of pelvic venous disorders (PeVD) and are increasingly being diagnosed in patients in phlebological offices these days. To investigate VVs potentially resulting from pelvic vein incompetence (PVI), a usual full duplex ultrasonography (DUS) of lower extremity veins in the upright position is recommended as well as DUS for evaluation of pelvic escape points (PELVs). Seven PELVs have been described, connecting the pelvic veins to the veins of the genital region and/or legs. There are two possible treatment options for pelvic origin VVs, top-down treatment such as pelvic vein embolization or treatment of iliac/renal vein compression if it is the cause of PVI and bottom-up treatment of PELVs and related VVs. The idea of the latter approach is to treat the causes of the external pelvic VVs in the genital region and VVs in the legs without having to treat asymptomatic pelvic veins within the pelvis. The most common methods of bottom- up treatment are sclerotherapy, surgical ligation and miniphlebectomy. The efficacy of such treatment approach for VVs of pelvic origin has been reported in the literature, whereas studies have failed to demonstrate good results of top- down treatment in the context of eliminating VVs of pelvic origin as well as minimizing the risk of VVs recurrence. Bottom-up treatment is a useful option to avoid unnecessary and more expensive pelvic vein embolization and should be considered as an initial therapeutic approach. Only if bottom-up treatment fails, if the VVs recur rapidly, or if the patient develops pelvic symptoms due to PVI, pelvic veins embolization can be considered.

Reference signal aided self-interference cancellation for in band full duplex underwater wireless optical communication

A novel self-interference cancellation method for in-band full-duplex (IBFD) underwater wireless optical communication (UWOC) system is proposed and experimentally verified. This method reduces the self-interference to its intrinsic noise level using a reference optical signal whose amplitude is opposite to the self-interference signal, together with a deep neural network to compensate for the nonlinear distortion enhanced by increased DC. The bit error rates (BERs) before and after self-interference cancellation at different data rates are tested and compared with the existed polarization-based cancellation scheme. Results presented in this paper show that more than 10 dB self-interference cancellation ratio can be achieved by the proposed scheme at 100 MHz signal rate, and outperforms the polarization-based scheme. With the assistance of the proposed method, a data rate of 100Mbps was achieved simultaneously at the uplink and downlink within IBFD based UWOC.

Performance analysis of full duplex and frequency reuse in NR‐V2X networks

AbstractThis paper employs full duplex (FD) and frequency reuse (FR) to improve the spectral efficiency while considering inter‐carrier interference (ICI) in 5G new radio vehicle‐to‐everything (NR‐V2X) networks. The quality of service of vehicle‐to‐vehicle (V2V) communications in such a system is affected by the self‐interference (SI) caused by FD, the co‐channel interference (CCI) caused by FR, and ICI caused by the Doppler effect. We present a performance analysis by proposing feasibility conditions for implementing FD and FR in NR‐V2X networks. We obtain a closed‐form expression for the maximum link distance between the transmitter and receiver of a link to provide reliable V2V communications. Our simulation results reveal the interplay between FD and FR technologies and demonstrate the performance gains of our proposed scheme compared to existing schemes in the literature.

Performance Analysis Of Relay Aided On Device To Device Communications Underlay 5G Cellular Network

The increasing development of today's technology specifically in the field of telecommunications triggers new problems associated with the increasing number of network connectivity users so that this makes the increased load of traffic on the Base Station (BS). To address traffic problems, a D2D technology is needed as a solution to enhance connectivity on 5G networks. In the use of D2D is still not optimal for dealing with the rapidly increasing load of traffic due to the large number of users. This research suggests the addition of devices in D2D communication, namely Relay Node. (RN). The results of the study showed that by using the relay aided communication scheme can improve the sumrate performance parameter is 1,970 × 107 bps and the spectral efficiency is 19,704 bpz/Hz, but less effective in the power efficiency parameter is 7,672 × 103 bps/mW due to the addition of relay devices that increase power consumption. Using iterative algorithms on relay aided communication schemes has been shown to improve performance parameters values more optimally than using full duplex and half duplex communications schemes. Therefore, the relay aided scheme is the most accurate communication scheme in dealing with transmission systems on D2D because by using the aided relay scheme, sumrate and spectral efficiency are improved by 55%.

Decoupled UL/DL User Association in Wireless-Powered HetNets With Full-Duplex Small Cells

In this paper, we propose two downlink (DL)-uplink (UL) decoupled (DUDe) user association schemes in wireless-powered full-duplex (FD) heterogeneous networks (HetNets). We consider a two-tier HetNet comprising of half-duplex (HD) massive multi-antenna macrocell base stations (MBSs) and dual-antenna FD small cell base stations (SBSs) to support UL and DL transmissions of FD user equipments (UEs). Each FD UE is first associated to one MBS/SBS, based on the mean maximum received power (MMP) scheme or maximum received power (MRP) to harvest energy. During the consecutive data transmission phase, UEs choose to receive DL traffic from the same MBSs/SBSs as that associated with during energy harvesting phase, and send UL traffic through the same/another SBS. Leveraging tools from the stochastic geometry, we develop an analytical framework to analyze the average harvested energy and derive expressions for the UL and DL coverage probabilities of the proposed DUDe user association schemes. Our results show that there is an optimal value for the SBS density in the wireless-powered FD HetNets, at which both DL and UL coverage probabilities are maximized. Moreover, by applying MMPA and MRPA scheme, wireless-powered FD HetNets with DUDe achieves up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$138.78\%$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$83.37\%$</tex-math></inline-formula> energy efficiency gain over the FD HetNets with DL/UL coupled user association scheme and without wireless power transfer, respectively.

Determining optimal paths of virtual links in Avionics Full-Duplex Switched Ethernet networks using modified ant colony optimization algorithm

The Aeronautical Radio Incorporated (ARINC) 664 Avionics Full Duplex Switched Ethernet (AFDX) data bus has been developed based on the Ethernet standard Institute of Electrical and Electronics Engineers (IEEE) 802.3, including redundancy, guaranteed bandwidth, and deterministic timing of transmit interval time to meet the increasing amounts of data exchange needs among aircraft equipment while reducing the harness weight. Isolated data tunnels, called Virtual Links (VLs), are established to route Ethernet frames from a single source to one or more destinations using end systems and switches that contain a static routing mechanism specific to ARINC 664 AFDX. A limited number of algorithmic approaches are presented in the literature to route VLs; however, they are proven in uncomplicated topologies. Depending on the technological development, the node amount consisting of End Systems (ESs), Switches, and Remote Data Concentrators (RDCs) in the aircraft data bus structure will increase enormously. Bandwidth utilization (BWU), bandwidth flexibility limit for further extensions, port usage, total harness weight, latency, and redundancy should be considered in addition to number of nodes to determine VLs’ route paths in ARINC 664 AFDX networks. In such cases, determining optimal paths of VLs in ARINC 664 AFDX networks becomes a challenging problem to solve with the existing methods in the literature. This paper proposes an Ant Colony Optimization (ACO) based algorithm to determine optimal VL path routes in the complex topology of ARINC 664 AFDX networks considering multi-effective parameters. Experimental simulations are executed to confirm the validity of the presented algorithm in different case studies and show its applicability in the industry. The obtained results of the proposed algorithm outperform conventional algorithms existing in the literature in terms of bandwidth usage depending on predefined expansion capacity and solution time. The proposed algorithm also introduces novelty by considering the redundancy, total harness weight, and delay limit, which is deficient in the existing literature.

High cost-effective photonic assisted in-band interference cancellation scheme for centralized radio access network towards future 5G communication

A photonic-assisted scheme capable of self-interference cancellation (SIC) and image rejection mixing (IRM) is demonstrated to solve the intractable problem of in-band interference for in-band full duplex (IBFD) systems with high frequency and large bandwidth. In the proposed scheme, a single optical path configuration is constructed based on an integrated modulator applied as the main device. The SIC operation is implemented in the optical domain making it immune to the influence caused by fiber dispersion. Owing to the intermediate frequency (IF) signal amplitude regulation mechanism under the combined action of fiber dispersion induced phase and double sideband (DSB) modulation, the scheme can realize IRM without increasing the system complexity. Experimental results show that the 50 MHz 16-quadrature amplitude modulation (16-QAM) signal of interest (SOI) centered at different frequencies are down-converted to 2.5 GHz. The depth of SIC and image-rejection (IR) is over 35 dB and 25 dB after transmitted through a span of 10.1 km optical fiber. The received 16-QAM down-converted signal can be recovered with an error vector magnitude (EVM) which satisfies the requirement of 3GPP-specified EVM limit. The signal recovery performance, SIC depth and image rejection ratio (IRR) under different signal to interference ratio (SIR) is also investigated. In addition, a comparison of relevant literature with this scheme from the perspective of technical discussion is also presented. The proposed scheme can realize effective functional integration with compact structure, simple parameter tuning mechanism, improved stability and high cost-effectiveness to solve the in-band interference problem which is of great value to be applied in IBFD centralized radio access networks (CRAN) towards future 5G communication.

A full duplex LG modes enabled millimeter-wave based FSO communication system for disaster zone

A full duplex LG modes enabled millimeter-wave based FSO communication system for disaster zone

Secrecy outage probability of DF‐based C‐NOMA under half and full duplex

AbstractCooperative Non‐orthogonal Multiple Access (C‐NOMA) is projected as the dominant technology for 5G and beyond. Also, physical layer security, due to the presence of eaves‐dropper, is a bottleneck security concern for any open link wireless system. This manuscript presents a novel Decode &amp; Forward (DF)‐based C‐NOMA system in the presence of two eavesdroppers. Moreover, both half duplex and full duplex schemes are included in the analysis. Thereby, separate expressions for Secrecy Outage Probability (SOP), being among the most crucial performance measures in physical layer security, are produced and examined for the system under consideration. Specifically, first of all, novel expression of SOP for C‐NOMA systems under both Half Duplex (HD) and Full Duplex (FD) schemes is derived for the case when only eavesdropper one (E1) attacks on link source to device one (S‐D1). Thereafter, expressions of SOP for the C‐NOMA system under both HD and FD schemes are derived, considering presence of E1 and E2 on the links, source to device one (S‐D1) and source to device two (S‐D2), respectively. Further, for both the duplexes, the effect of eavesdropper one (E1) and eavesdropper two (E2) on the links, S‐D1 and S‐D2, respectively, is analyzed. The presented analysis is useful in the technological development level of C‐NOMA in the presence of multiple eavesdroppers. The simulated results show perfect agreement with the theory.

Joint IRS Location and Size Optimization in Multi-IRS Aided Two-Way Full-Duplex Communication Systems

Intelligent reflecting surfaces (IRSs) have emerged as a promising wireless technology for the dynamic configuration and control of electromagnetic waves, thus creating a smart (programmable) radio environment. In this context, we study a multi-IRS assisted two-way communication system consisting of two users that employ full-duplex (FD) technology. More specifically, we deal with the joint IRS location and size (i.e., the number of reflecting elements) optimization in order to minimize an upper bound of system outage probability under various constraints: minimum and maximum number of reflecting elements per IRS, maximum number of installed IRSs, maximum total number of reflecting elements (implicit bound on the signaling overhead) as well as maximum total IRS installation cost. First, the problem is formulated as a discrete optimization problem and, then, a theoretical proof of its NP-hardness is given. Moreover, we provide a lower bound on the optimum value by solving a linear-programming relaxation (LPR) problem. Subsequently, we design two polynomial-time algorithms, a deterministic greedy algorithm and a randomized approximation algorithm, based on the LPR solution. The former is a heuristic method that always computes a feasible solution for which (a posteriori) performance guarantee can be provided. The latter achieves an approximate solution, using randomized rounding, with provable (a priori) probabilistic guarantees on the performance. Furthermore, extensive numerical simulations demonstrate the superiority of the proposed algorithms compared to the baseline schemes. Finally, useful conclusions regarding the comparison between FD and conventional half-duplex (HD) systems are also drawn.

Power Optimization of Cell-Free Massive MIMO With Full-Duplex and Low-Resolution ADCs

This paper analyzes the spectral/energy efficiency (SE/EE) of a full-duplex (FD) cell-free (CF) massive multiple-input multiple-output (mMIMO) over Rician fading channels. Due to the FD radios, the access points (APs) suffer from self-interference (SI) and inter-AP interference (IAI) while the downlink (DL) users’ signals are corrupted by the uplink (UL) users’ transmissions. We consider the case, where low-resolution analog-to-digital converters (ADCs) are utilized at the APs and DL users, which introduces the quantization noise (QN). The combined effects of Rician κ-factor, residual SI/IAI, UL-to-DL interference, multi-user interference, and QN on the UL/DL SEs are characterized. The UL SE is degraded by the increase in DL power, whereas the growth in UL power deteriorates the DL SE. The effects of the residual SI/IAI and UL-to-DL interference are worsened by the low-resolution ADCs. We optimize the UL/DL transmit powers to maximize the overall sum SE of the network. It is observed that the proposed power allocation algorithm brings substantial sum SE gain. A trade-off analysis between the EE and SE, as a function of the ADCs’ resolution, shows that the entire envelope of the operating region of FD CF mMIMO is enhanced in Rician channels.