Duplex Wireless Research Articles

Polar coded cooperative with Plotkin construction and quasi‐uniform puncturing based on MIMO antennas in half duplex wireless relay network

AbstractRecently, polar code has attracted the attention of many scholars and has been developed as a code technology in coded‐cooperative communication. We propose a polar code scheme based on Plotkin structure and quasi‐uniform punching (PC‐QUP). Then we apply the PC‐QUP to coded‐cooperative scenario and built to a new coded‐cooperative scheme, which is called PCC‐QUP scheme. The coded‐cooperative scheme based on polar code is studied on the aspects of codeword construction and performance optimization. Further, we apply the proposed schemes to space–time block coding (STBC) to explore the performance of the scheme. Monte Carlo simulation results show that the proposed cooperative PCC‐QUP‐STBC scheme can obtain a lower bit error ratio (BER) than its corresponding noncooperative scheme.

2 × 2 MIMO In-Band Full Duplex Radio Front-End With Two-Stage Passive Suppression and Four Three-Tap RF Cancellers

2 × 2 MIMO In-Band Full Duplex Radio Front-End With Two-Stage Passive Suppression and Four Three-Tap RF Cancellers

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.

SIW-based frequency-adjustable antenna for IoT-based duplex wireless devices

This paper proposes a compact and frequency-adjustable/reconfigurable dielectric (DR)-loaded eighth-mode substrate integrated waveguide (EMSIW) antenna for duplex wireless communications. The miniaturization of the resonators is realized using a rectangular slot and high isolation is achieved by keeping a reasonable space between them. The proposed design is simulated using a three-dimensional (3D) full-wave simulator, then analysed with a circuit model and finally validated experimentally. Frequency-reconfigurability in the suggested antenna is achieved by placing DRs with different permittivities in the designated holes that are realized in the open-ended portion of each resonator. Consequently, the lower- and high-resonant bands can be reconfigured from 4.70 to 5.23 GHz and from 5.55 to 6.34 GHz, respectively. It is worth mentioning that both resonant band can be independently reconfigured. Moreover, the inter-resonator coupling is always lower than −23.5 dB in the bands of interest. Furthermore, the peak realized gains are always greater than 4.7 dBi in the lower frequency band and 5.5 dBi in the higher one. The suggested antenna has stable radiation properties in both bands in all frequency ranges. Hence, this design is suitable for compact reconfigurable devices due to its compactness, large frequency ranges, stable radiation patterns, and high isolation.

Machine learning assisted delay minimization in full duplex energy constrained cooperative communication network

Cooperative communication is key in attaining high network throughput and better coverage area for a wireless powered communication network. The conventional solution methodologies proposed in the literature for these networks suffer from high run-time complexity. This paper presents an efficient polynomial-time machine learning approach for solving the total transmission time minimization problem through relay selection and scheduling of the users in a full duplex wireless powered cooperative communication network. Exploiting the simplicity offered by the tree ensemble models, a distributed gradient-boosted decision tree based model (XGBoost) is incorporated. The inputs of the model are the uplink channel coefficients and energy harvesting rates of the relays and the users, and outputs are the optimal completion time of the relays and users, relay selection and schedule of the users. Simulation results indicate that the proposed model very well approximates the true outputs, i.e., performs very close to the optimal solution of the optimization problem, while maintaining a very low run-time computational complexity. Specifically, for a network of 9 users, the run-time of the proposed model is just 25% of the optimal solution, and this ratio grows as the number of users increases in the network.

RF CMOS Duplexers for Frequency-Division Duplex Radios: The Most Recent Developments

One main challenge for modern mobile communication systems is simultaneous demand for higher data rates (performance) and lower power consumption and size (cost). One way to increase wireless data transfer capacity is to employ frequency-division duplex (FDD) wireless systems where both transmitter (Tx) and receiver (Rx) work at the same time but in two different frequency bands with sufficient amount of guard band between them. An FDD system requires sharing the antenna between Tx and Rx [ <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1(a)</xref> ]. Because of the simultaneous operation of Tx and Rx units, modern FDD front-end realizations face numerous challenges, as shown in <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1(b)</xref> :

A New Online Nonlinear Self-Interference Cancelation Method With Random Fourier Features

In this letter, we present a new online nonlinear digital self-interference cancelation method for full duplex radios. In this method, random Fourier features transformation is performed before utilizing the least mean squares algorithm, which is applied to the residual of linear digital cancelation. The proposed solution’s performance is evaluated against prominent nonlinear cancelation schemes on the same full duplex radio set-up, consisting only of a monostatic antenna and a WARP v3 board. Our experimental results show that the proposed solution provides the highest self-interference cancelation while reducing the complexity of the batch solutions by up to two orders of magnitude.

Joint pilot design and beamforming optimization in massive MIMO surveillance systems

This paper proposes a novel joint channel estimation and beamforming scheme for the massive multiple-input-multiple-output (MIMO) frequency-division duplexing (FDD) wireless legitimate surveillance system. With the proposed scheme, the monitor with the full duplex capability realizes the proactive eavesdropping of the suspicious link by leveraging the pilot attack approach. Specifically, exploiting the effective eavesdropping rate and the mean square error as performance metrics and setting a total power budget at the training and transmission phases, while guaranteeing the information from suspicious source can be successfully decode, joint pilot design, power allocation and beamforming strategy are formulated as optimization problems for the two objective functions: MSE and effective eavesdropping rate. A closed-form expression of the optimal pilot with the limited length can be obtained via the channel correlation. The optimal power problem at the training phase can be solved by a simple bisection method. Then, based on the obtained imperfect estimated channel, the jamming beamforming at monitor optimization algorithm is proposed by utilizing the convex Semidefinite Programming approach to maximize the effective eavesdropping rate. Numerical results show that the proposed joint pilot design, power allocation and beamforming optimization scheme can improve the surveillance performance of the legitimate monitor as compared to the existing passive eavesdropping and jamming-assisted eavesdropping.

A Bidirectional RoF System for the Multi-Band Signal with Mitigation of the Nonlinear Effects

A bidirectional full duplex radio over fiber (RoF) system is proposed for multi-band signal generation and transmission. A multi-band signal is generated at the central station (CS), which includes 10 GHz baseband, 40, and 70 GHz millimeter-wave (mm-wave) by optical frequency multiplication technique of radio frequency (RF) local oscillator (LO) with frequency of 15 GHz. The simultaneous transmission of the 16-QAM OFDM-based multi-band downlink signal and 4-QAM uplink signal over a single fiber is demonstrated. The carrier for uplink transmission is extracted from the unmodulated downlink signal with tunable FBG which is modulated by OFDM-based 4-QAM uplink data obtained from the user end via an antenna. The frequency reuse from the downlink signal makes the base station (BS) free from the laser source. At the user end, the multi-band signals for multi-serve application are obtained by heterodyne beating of multiple bands. An increase in launch power induces fiber dispersion and non-linearities like self-phase modulation (SPM) and cross phase modulation (XPM), which depends on the nonlinear refractive index of the fiber. Different industrial standard fibers with common specifications and modulation format along with co-shared components are deployed, and system performance is analyzed. The stimulated Brillouin scattering (SBS) can be mitigated by optimizing the launch power within the SBS threshold. The nonlinear effects are minimized at the system level without the requirement of additional digital signal processor (DSP) . The theoretical and simulation analysis shows that the designed bidirectional RoF link exhibits an improved system performance for bidirectional transmission with negligible power penalty.

Practical Hybrid Beamforming for Millimeter Wave Massive MIMO Full Duplex With Limited Dynamic Range

Full Duplex (FD) radio has emerged as a promising solution to increase the data rates by up to a factor of two via simultaneous transmission and reception in the same frequency band. This paper studies a novel hybrid beamforming (HYBF) design to maximize the weighted sum-rate (WSR) in a single-cell millimeter wave (mmWave) massive multiple-input-multiple-output (mMIMO) FD system. Motivated by practical considerations, we assume that the multi-antenna users and hybrid FD base station (BS) suffer from the limited dynamic range (LDR) noise due to non-ideal hardware and an impairment aware HYBF approach is adopted by integrating the traditional LDR noise model in the mmWave band. In contrast to the conventional HYBF schemes, our design also considers the joint sum-power and the practical per-antenna power constraints. A novel interference, self-interference (SI) and LDR noise aware optimal power allocation scheme for the uplink (UL) users and FD BS is also presented to satisfy the joint constraints. The maximum achievable gain of a multi-user (MU) mmWave FD system over a fully digital half duplex (HD) system with different LDR noise levels and numbers of the radio-frequency (RF) chains is investigated. Simulation results show that our design outperforms the HD system with only a few RF chains at any LDR noise level. The advantage of having amplitude control at the analog stage is also examined, and additional gain for the mmWave FD system becomes evident when the number of RF chains at the hybrid FD BS is small.

Analog self-interference cancellation based on zero-forcing sampling for in band full duplex radios

A uniformly zero-forcing sampling method applied in the base-band analog domain is proposed for Self-Interference Cancellation (SIC) in Band Full-Duplex (IBFD) radios. In order to releasing the ADC dynamic range to enable the desired signal for further processing in the digital domain, the SIC is performed when ADC samples the received signal. Specifically, first, an auxiliary signal is designed to rectify the zero-crossings of the self-interference (SI) to be consistent with the ADC sampling points. Second, to achieve the auxiliary signal, a zero-forcing function is established by leveraging one-to-one mapping from the complex domain to the complex exponential domain. Meanwhile, a closed-form expression of the zero-forcing function is derived according to the Z transformation. Additionally, an orthogonal pilot structure is proposed to improve the SIC capability, and the computational complexity is investigated. Finally, simulation and experimental results show the effectiveness of the proposed method.

Adaptive Irregular Constellations for Full-Duplex Relaying With Residual Self-Interference

We propose the use of adaptive optimized irregular constellation to enhance the performance of full duplex (FD) wireless radio systems which suffer from residual self-interference (RSI). Specifically, an error performance expression which takes into account the RSI level and signal-to-noise ratio is first derived for a single FD relay link. During the search for optimal constellation for a given parameter set, there are no predefined assumptions on symbol point locations. The optimization framework yields adaptive irregular constellations depending on RSI levels and power budget values. It is shown that the proposed adaptive transmission along with optimized irregular constellations achieves better error performance than the conventional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -QAM constellations and other <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -ary improper Gaussian signaling (IGS) constellations.

Minimum Length Scheduling for Multi-Cell Full Duplex Wireless Powered Communication Networks.

Wireless powered communication networks (WPCNs) will be a major enabler of massive machine type communications (MTCs), which is a major service domain for 5G and beyond systems. These MTC networks will be deployed by using low-power transceivers and a very limited set of transmission configurations. We investigate a novel minimum length scheduling problem for multi-cell full-duplex wireless powered communication networks to determine the optimal power control and scheduling for constant rate transmission model. The formulated optimization problem is combinatorial in nature and, thus, difficult to solve for the global optimum. As a solution strategy, first, we decompose the problem into the power control problem (PCP) and scheduling problem. For the PCP, we propose the optimal polynomial time algorithm based on the evaluation of Perron–Frobenius conditions. For the scheduling problem, we propose a heuristic algorithm that aims to maximize the number of concurrently transmitting users by maximizing the allowable interference on each user without violating the signal-to-noise-ratio (SNR) requirements. Through extensive simulations, we demonstrate a 50% reduction in the schedule length by using the proposed algorithm in comparison to unscheduled concurrent transmissions.

A reinforcement learning approach to queue-aware scheduling in full-duplex wireless networks

Full-duplex communications promise to double the throughput of a wireless network, so long as the resulting interferences can be combated. Nonetheless, already dealing with the intricacy of determining base station-to-user radio channels, full duplex wireless networks need additional information on the channels in between all the user equipment. This information is necessary to determine user radio conditions, and thereafter efficiently allocate resources. A signaling overhead is likely to burden the user equipment, which already lack any methods to estimate and convey such user-to-user channel states. In this paper, we aim to circumvent the complexities and requirements of traditional scheduling techniques by introducing a reinforcement learning based scheduling algorithm for full-duplex wireless networks. This scheduling approach does not need to estimate user-to-user channels, and rather learns how to best allocate the network’s radio resources. We show that our proposal can match scheduling with complete channel state information in terms of user equipment throughput, and that it performs well under multiple testing scheduling scenarios: increased user equipment numbers, randomized user equipment demand, and user equipment clustering among others.

Analog Least Mean Square Adaptive Filtering for Self-Interference Cancellation in Full Duplex Radios

In-band full duplex (IBFD) radio represents one of the key technologies for future wireless communication and radar applications. A major challenge of this technology is to mitigate the strong self-interfer-ence (SI) so that the residual SI level falls below the receiver's noise floor. Radio frequency (RF) self-inter-ference cancellation (SIC) is essential for preventing an IBFD receiver from becoming saturated by the SI. We commence with an in-depth review of the promising analog least mean square (ALMS) adaptive filtering architecture, conceived for RF SIC in the IBFD radio RF front-end. The cancellation circuits employing this architecture can be implemented purely by analog components without any involvement of more power-thirsty digital signal processing. The behaviors, performance, and implementation of the ALMS loop are presented. Finally, their applications in various IBFD radios are discussed, and future research directions are provided.

Intelligent security relay selection for full duplex wireless communications

Intelligent security relay selection for full duplex wireless communications

Full duplex wireless communiation with dynamic buffer aided MAC protocol

This paper presents a dynamic buffer aided medium access control protocol for asymmetric traffic conditions in an IoT network, where the IoT devices send data to a wireless access point (WAP) which then forwards the data to the network fusion center. Specifically, the control frame structures of conventional carrier sense multiple access with collision detection (CSMA/CD) protocol are modified for incorporating the traffic asymmetry of the network. The devices and WAP are assumed to have full duplex abilities to support continuous sensing of the channel. The sensing performance of the considered system is derived for arbitrary number of devices in terms of probabilities of false alarm and miss detection. Moreover, the throughput of the network is also obtained. Simulation results show that the proposed cross-layer design achieves significant throughput improvement while incorporating traffic asymmetry of the network.

Throughput maximization in discrete rate based full duplex wireless powered communication networks†

In this study, we consider a discrete rate full‐duplex wireless powered communication network. We characterize a novel optimization framework for sum throughput maximization to determine the rate adaptation and transmission schedule subject to energy causality and user transmit power. We first formulate the problem as a mixed integer nonlinear programming problem, which is hard to solve for a global optimum in polynomial‐time. Then, we investigate the characteristics of the solution and propose a polynomial time heuristic algorithm for rate adaptation and scheduling problem. Through numerical analysis, we illustrate that the proposed scheduling algorithm outperforms the conventional schemes such as equal time allocation half‐duplex and on‐off transmission schemes for different initial battery levels, hybrid access point transmit power and network densities.

Towards Green and Soft: 5G Design Considerations

As the commercial deployment of 4G systems is picking up, technologists worldwide are beginning to search for next-generation wireless solutions to meet the anticipated demands in the 2020 era given the explosive growth of mobile Internet and the Internet of Things (IoT). This article presents our perspectives of the 5G technologies with two major themes: Green and Soft. By rethinking the Shannon theorem and traditional cell-centric design, network capacity can be significantly increased while network power consumption is steady or even decreased. The feasibility of the combination of Green and Soft is investigated through five interconnected areas of research: energy efficiency and spectral efficiency co-design, no more cells, rethinking signalling/control, invisible base stations, and full duplex radio.

Performance analysis of MIMO and MISO time division duplexing wireless links with SWIPT and antenna selection

It is expected that many small battery-operated devices will connect to next generation of cellular networks. In this work, a two-way wireless link is considered, where due to slow variations of the channel, forward link (FL) and reverse link channels are reciprocal, and the remote device’s battery is charged via wireless energy harvesting. We analyze the performance of a two-way link setup, with very low complexity signal processing at the node that relies on battery, and consists of antenna selection and maximum ratio combining-based multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) techniques, wherein FL simultaneous wireless information and power transmission is assumed to be utilized. By mathematical tractability, a closed-form analytical expression for probability of outage, ergodic capacity and bit error rate are derived and compared with simulation results. It is shown that the assumed low complexity setup achieves full diversity in both cases of MISO and MIMO.