Transceiver System Research Articles

Green and Highly Efficient MIMO Transceiver System for 5G Heterogenous Networks

The paper presents the general requirements and an exemplary design of the RF front-end system that in today’s handset is a key consumer of power. The design is required to minimize the carbon footprint in mobile handsets devices, whilst facilitating cooperation, and providing the energy-efficient operation of multi-standards for 5G communications. It provides the basis of hardware solutions for RF front-end integration challenges and offers design features covering energy efficiency for power amplifiers (PAs), Internet of Things (IoT) controlled tunable filters and compact highly isolated multiple-input and multiple-output (MIMO) antennas. An optimum design requires synergetic collaboration between academic institutions and industry in order to satisfy the key requirements of sub-6 GHz energy-efficient 5G transceivers, incorporating energy efficiency, good linearity and the potential for low-cost manufacturing. A highly integrated RF transceiver was designed and implemented to transmit and receive a picture using compact MIMO antennas integrated with efficient tunable filters and high linearity PAs. The proposed system has achieved a bit error rate (BER) of less than 10–10 at a data rate of 600 Mb/s with a wireless communication distance of more than 1 meter and power dissipation of 18–20 mW using hybrid beamforming technology and 64-QAM modulation.

A Crest Factor Reduction Technique for LTE Signals with Target Relaxation in Power Amplifier Linearization.

The signal conditioning treatment to achieve good relation of power with radio-frequency (RF) conversion in conventional transceiver systems require precise baseband models. A developed framework is built to provide a demonstration of the modeling figures of merit with orthogonal frequency division multiplexing (OFDM) support under signal conditioning and transmission restrictions to waveforms with high peak to average power ratio (PAPR) in practical applications. Therefore, peak and average power levels have to be limited to correct high PAPR for a better suited correction power from the amplifier that can lead to compression or clipping in the signal of interest. This work presents an alternative joint crest factor reduction (CFR) algorithm to correct the performance of PAPR. A real-time field-programmable gate array (FPGA) testbed is developed to characterize and measure the behavior of an amplifier using a single-carrier 64–QAM OFDM based on long-term evolution (LTE) downlink at GHz as stimulus, across wide modulation bandwidths. The results demonstrate that the CFR accuracy capabilities for the signal conditioning show a reliable clipping reduction to give a smooth version of the clipping signal and provide a factor of correction for the unwanted out-of-band emission validated according to the adjacent channel power ratio (ACPR), PAPR, peak power, complementary cumulative distribution function (CCDF), and error vector magnitude (EVM) figures of merit.

Constant Voltage Charging and Maximum Efficiency Tracking for WPT Systems Employing Dual-Side Control Scheme

The wireless power transfer (WPT) system has been gradually integrated into our daily applications due to its advantages of security, esthetics, and convenience. Generally, for a complete WPT system, two main goals need to be achieved: one is the constant voltage (CV) output and the other is the highest possible transfer efficiency. However, the highest possible transfer efficiency is difficult to achieve when the WPT system maintains the CV output against the time-varying load resistance and coupling coefficient. In this article, a new dual-side control scheme that employs transmitter-side high-frequency inverter (HFI) and receiver-side semi-active rectifier (SAR) is proposed to simultaneously achieve the CV output and maximum efficiency tracking (MET) control regardless of the variable load resistance and coupling coefficient. It is proved that the system can obtain the maximum transfer efficiency when the derivative of <inline-formula> <tex-math notation="LaTeX">$\sin (\alpha /2)$ </tex-math></inline-formula> with <inline-formula> <tex-math notation="LaTeX">$\sin (\beta /2)$ </tex-math></inline-formula> is a specific constant, which is determined by self-resistances of transceiver coils and system input and output dc voltage. In the above derivative, <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> are phase shift angles of the HFI and SAR, respectively. The CV output is maintained by adjusting <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>, while the MET control is performed by continuously adjusting <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>. A confirmatory experimental setup with the charging voltage of 72 V is built, and the experimental results fully prove the correctness and effectiveness of the proposed scheme.

Joint Digital Online Compensation of TX and RX Time-Varying I/Q Mismatch and DC-Offset in mmWave Transceiver System

Joint Digital Online Compensation of TX and RX Time-Varying I/Q Mismatch and DC-Offset in mmWave Transceiver System

Green ultra-wideband antenna utilizing Mie resonances in cactus

While plants are typically supposed to restrict the performance of radio frequency transceiver systems, they can act as efficient biogenic elements of control. A high fraction of water inside vegetation gives rise to multiple electromagnetic Mie resonances, originating from interplaying a naturally high permittivity and a form factor. Opuntia ficus-indica, known as nopal cactus, is a representative example whose succulent stems or cladodes contain nearly 75–85% water. Here, we present an Opuntia-based broadband omnidirectional antenna element, operating at several Wi-Fi communication bands, spanning from 900 MHz to 7.7 GHz. A high relative permittivity in the GHz range exceeds 20. As a result, a variety of Mie resonances within the cladode are measured and revealed by the multipole expansion technique. Modal hierarchy, resonantly excited with a coaxial cable, is demonstrated to provide a broadband impedance matching below −10 dB over the ∼150% bandwidth. Further investigations of plants as functional electromagnetic elements can contribute to the general trend of environment friendly multifunctional devices, promoting development of green technologies.

Investigation of Different CW Laser Parameters for 640 Gbps DWDM Transceiver System

This paper demonstrate design of 16 channel Dense Wavelength Division Multiplexing (DWDM) transceiver system and analyze the effect of Continuous Wave (CW) laser parameter on the transmission of data. The proposed system designed to support data rate of 640 Gbps and by using the software of Optisystem 18. The parameters included with investigation are the CW laser extinction ration, CW laser power, and channel spacing. The investigation for these parameters would be based on their effect on the parameters of Quality Factor (QF) and Bit Error Rate (BER). In this study, the effect of chromatic dispersion would be involved along with investigation to and handled during transmission by using Dispersion Compensation Fiber (DCF). Analyzing results obtained indicate the best outcome of these studied parameters and the relation between them and both the QF and BER.

Inversion method of two-dimensional distribution of electron density in hypersonic model wake

The ballistic target uses a two-stage light gas gun to launch the model into a hypersonic state, and the model forms a plasma wake when flying at a hypersonic speed in the target chamber. In order to obtain the radial two-dimensional distribution of transient plasma electron density in the wake of hypervelocity model, a seven-channel Ka-band microwave interferometer measuring system is developed. In the transceiver system, a transmitting antenna achieves the plane wave irradiation plasma, and a seven-port array antenna is used to receive plane waves which are passing through the plasma: the antenna beam can completely cover the radial range of the wake. The shortest response time of measuring system is 1 s, and electron density measurement range of the interferometer measuring system is 10&lt;sup&gt;11&lt;/sup&gt;–10&lt;sup&gt;13&lt;/sup&gt;/cm&lt;sup&gt;3&lt;/sup&gt; . The plasma is often treated as layered medium in data processing of multichannel microwave interferometer. Taking into consideration the effect of refraction on the stratified interface in this work, the ray tracing (RT) method is used to establish the electromagnetic propagation model. Combined with the measurement data to construct the objective function, the genetic algorithm (GA) is used to invert the radial two-dimensional distribution of the electron density under different test conditions. The result shows good agreement with the numerical simulation under the same test state, which proves the the data processing method reliable. Then, the influence of the layered model on the calculation result is analyzed, which shows that the seven-layer model is suitable for the wake modeling under given experimental conditions, and thus maximizing the number of receiving channels and ensuring the accuracy. The RT method is used for the first time to achieve the two-dimensional distribution of electron density in the wake of hypervelocity projectile, and some rules of two-dimensional electron density distribution of the hypersonic model under given experimental conditions are realized.

Study on Retrieval Method of Two-dimensional Distribution of Hypersonic Model Wake Electron Density

The ballistic range uses a two-stage light gas gun to launch the model into a hypersonic state, and the model form a plasma wake when flying at hypersonic speed in the target chamber. In order to obtain the radial two-dimensional distribution of transient plasma electron density in the wake of hypervelocity model, a seven channels Ka-band microwave interferometer measuring system was developed. In the transceiver system, one transmitting antenna to achieve plane wave irradiation plasma, and a seven-port array antenna is used to receive plane waves which passing through the plasma, the antenna beam can completely cover the radial range of the wake. Measuring system shortest response time and electron density measurement range of the interferometer measuring system are 1&lt;teshuzifu&gt;ms and 10&lt;sup&gt;11&lt;/sup&gt;-10&lt;sup&gt;13&lt;/sup&gt;/cm&lt;sup&gt;3&lt;/sup&gt; respectively. Plasma is often treated as layered medium in data processing of multichannel microwave interferometer, consider the effect of refraction on the stratified interface, in this work, the ray tracing(RT) method is used to establish the electromagnetic propagation model, combined with the measurement data to construct the objective function, and the genetic algorithm(GA) is used to invert the radial two-dimensional distribution of the electron density under different test conditions. The result shows that it is in good agreement with the numerical simulation under the same test state, which proves the reliability of the validity of the data processing method. Then, the influence of the layered model on the calculation result is analyzed, which shows that the seven-layers model is suitable for the wake modeling under given experimental conditions, maximizing the number of receiving channels and ensuring the accuracy. RT method is used for the first time to achieve the two-dimensional distribution of electron density in the wake of hypervelocity projectile, and some rules of two-dimensional electron density distribution of the hypersonic model under given experimental conditions are realized.

Design and Testbed Implementation of Blind Parameter Estimated OFDM Receiver

Designing an intelligent or adaptive transceiver system is becoming a promising technology for upcoming generations of wireless communication systems due to its adaptivity, spectrum efficiency, and low-latency characteristics. However, there is no work available until now that characterizes and demonstrates complete adaptation in the physical layer for orthogonal frequency-division multiplexing (OFDM) systems. In this article, we propose and implement sequential blind parameter estimation methods for OFDM signals using radio frequency (RF) testbed setup in a realistic scenario. The estimations include the number of subcarriers, symbol duration, cyclic prefix, oversampling factor, symbol timing offset (STO), and carrier frequency offset (CFO). The proposed algorithms also include blind modulation classification for linearly modulated signals over a frequency-selective fading channel. The parameter estimation has been carried out through a cyclic cumulant process. The modulation formats are classified by using normalized fourth-order cumulant in the frequency domain. The STO and CFO are estimated by a proposed modified maximum likelihood algorithm. The performances of parameter estimations, modulation classification, and synchronization are measured through analytical, simulation, and measurement studies. The overall performance of the OFDM system is provided in terms of the received constellation diagram and bit error rate (BER) over an indoor propagation environment.

Low-Cost Circularly Polarized Millimeter-Wave Antenna Using 3D Additive Manufacturing

An efficient single-layer printed feed is used with a low-cost 3D printed polarizer. The feed is made on a single substrate layer. The proposed antenna gain is 15 dBi, and the overlapped impedance-axial ratio bandwidth is 20%. The proposed structure is a low-cost structure that can be fabricated in any modest fabrication facility. The feed does not require any plated vias, which tremendously simplifies the fabrication process and lowers the cost. The feed is very well suited for integration with integrated circuit transceiver systems. The proposed structure does not require any feeding network design. Hence, it relaxes the design process and avoids the losses associated with such feeding network. The proposed element can be employed in an array configuration with adequately suppressed side lobes. The element cost, simplicity, and gain performance are superior to other proposed solutions in the literature.

Predistortion-Based Linearization for 5G and Beyond Millimeter-Wave Transceiver Systems: A Comprehensive Survey

The next-generation (5G/6G) wireless communication aims to leapfrog the currently occupied sub-6 GHz spectrum to the wideband millimeter-wave (MMW) spectrum. However, MMW spectrums with high-order modulation schemes drive the power amplifier (PA) at significant back-off, causing severe nonlinear distortions, thus deteriorating the transceiver&#x2019;s (TRXs) modulation process. Typically, the TRX efficacy is quantified with standardized linearization matrices, which take advantage of different predistortion (PD) schemes to handle deep compression of the PA. In this regard, TRX baseband signals are mostly linearized in the digital domain, where digitally controlled linearization needs higher sampling rates due to increasing MMW bandwidths to compensate for intermodulation (IMD) products, resulting in increased system cost and power consumption. Alternately, the digitally controlled analog-based linearization, i.e., the hybridization of digital predistortion (DPD) and analog predistortion (APD), is highly productive and cost-effective for fulfilling the linearized energy-efficient design vision of MMW networks. Therefore, this paper puts an extensive spotlight on the progress in PD-based linearization for 5G and beyond communications. It first provides background information on the advancements of PD schemes through recent surveys, then classifies the general roadmap of PD waveform processing across the TRX system models as preliminary. After this, we present three prominent PD architectures and their design approaches with intrinsic performance metrics. Finally, we explore four case studies encompassing PD operation under certain nonlinear constraints of different communication schemes. We examine the suitability of PD-based linearization solutions, both existing and proposed till the first quarter of 2022, and identify the potential prospects in this domain.

Novel Unipolar Optical Modulation Techniques for Enhancing Visible Light Communication Systems Performance

Visible Light Communications (VLC) are receiving increased attention in the wireless communications research community. VLC is secured, power efficient, and operates in the visible light range, thus RF communication bandwidth limitation is overcome. In this article, the authors enhance the data rate, system complexity, power efficiency, and spectrum efficiency in VLC systems. An innovative unipolar transceiver system is proposed, mathematically analyzed, and compared with other existing techniques and it demonstrates to have a very high data rate ratio (43.75%) with a good system bit energy to noise ratio (<i>E_b/N_o</i>) compared to other existing techniques. Development for the traditional asymmetrically and symmetrically clipping optical (ASCO-OFDM) system is also proposed, which involves combining a modified receiver with the ASCO-OFDM system traditional transmitter. The proposed receiver reduces the system complexity by O (<i>N</i> log₂ <i>N</i>) with better <i>E_b/N_o</i> than the conventional ASCO-OFDM. Detailed analysis, simulation results, and comparison of the proposed systems with the existing systems are presented beside a brief assessment of existing techniques.

A 120-Gb/s 100–145-GHz 16-QAM Dual-Band Dielectric Waveguide Interconnect With Package Integrated Diplexers in Intel 16

This paper presents a dual-band superheterodyne transceiver system in Intel 16 operating at 109 and 135 GHz center frequencies with a measured rejection &#x003E;60dB within the 11 GHz guard band. The transceiver is flip-chip assembled on a multilayer organic package, which integrates hairpin resonator diplexers and electromagnetic waveguide launchers. A connector assembled on the organic package feeds a 3-4 m long PTFE dielectric waveguide ensuring a stable mechanical connection. This paper demonstrates up to 120 Gbps data rates with measured EVMs between -19.2 dB to -16.2 dB at 3-4 m distances with combined power consumption of 1116 mW. This is the first work in literature reporting beyond 60 Gbps over dielectric waveguide channels at link distances greater than 1 meter. Combing frequency division multiplexing with a low tap count FFE equalizer and sharp on-die analog and RF filtering with a low loss on package diplexer enabled the &#x003E;100 Gbps at multi-meter distances.

Formation of service information in telemetry systems with data compression

In telemetry systems, using irreversible data compression, several message generation methods can be used. In the channel output packet, there may be several code words defining its composition. They can be combined and arranged in a strictly defined sequence. Such a data packet is a constant or variable length code combination, wherein the constant length of the packet is generated in the case of a predetermined and unchanged amount of information at the data output interval, and the variable is otherwise generated. The channel data packet can then be treated as a single whole: provide it with address information about the source of the message, information about the time interval at which the packet was formed, to bind significant samples to time, additional check symbols and codes to increase interference immunity of transmission, or to form a packet structure in the same way. Address, time and synchronization information in the literature is called overhead. The need to transmit overhead information reduces the efficiency of the transceiver systems. Therefore, the problem of reducing the volume of service information is extremely urgent.

A six‐port network based on substrate integrated waveguide coupler with metal strips

In this study, a novel coupling structure based on half-mode substrate-integrated waveguide (HMSIW) is proposed with a small size and broad bandwidth. The HMSIW coupler is realised by connecting their equivalent magnetic walls with metal strips, which avoids exposing the semi-enclosed magnetic walls outside. Hence, it has greater anti-interference capability than the existing HMSIW couplers. The directional coupling principle is introduced by analysing the proposed single connecting strip coupler. In order to lower return loss and higher isolation, a 3 dB directional coupler working from 10.8 to 16.8 GHz is designed with two connecting strips. Finally, a six-port circuit is achieved by utilising this compact 3 dB directional coupler. Furthermore, a broadband HMSIW power divider is optimised to satisfy the performance of this six-port circuit. The proposed coupler with metal strips helps to increase bandwidth and reduce size, which makes it more applicable to demanding systems with complex requirements such as detecting and transceiver systems. The 3 dB coupler and six-port circuit are fabricated and measured. The measured results are in accordance with the simulated data.

A 220-GHz Power Amplifier With 22.5-dB Gain and 9-dBm P sat in 130-nm SiGe

A 220-GHz power amplifier (PA) with high gain, high output power, and high efficiency for a 220-GHz transceiver system is presented in this letter. At terahertz (THz) and sub-terahertz (sub-THz) bands, the maximum available gain/maximum stable gain (MAG/MSG) of the device degrades rapidly, which increases the difficulty of high-gain and high-efficiency PA design. In this letter, the gm-boosting technique is analyzed and used in differential cascode (CC) topology to boost the gain of the single stage. Metal–oxide–metal (MOM) capacitors are used to reduce the insertion losses of the matching networks, therefore enhancing the gain and efficiency. The proposed PA exhibits a measured gain of 22.5 dB at 225 GHz with a 3-dB bandwidth of 35 GHz from 204 to 239 GHz. The measured OP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1dB</sub> of 6.0 dBm and the peak power added efficiency (PAE) of 2.96% are achieved at 215 GHz. The measured <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm {sat}}$ </tex-math></inline-formula> is larger than 9 dBm from 200 to 216 GHz. The PA occupies a small area of 0.162 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with a compact core area of 0.069 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The power consumption of the chip is 245 mW. From the aspect of overall performances, including gain, output power, efficiency, and chip area, this work exhibits one of the best performances in silicon-based PAs at sub-THz bands. Besides, to the best of our knowledge, the proposed PA exhibits the highest efficiency in silicon-based implementations beyond 210 GHz.

포토닉스 기반 FMCW 레이다 송수신 시스템 설계

Photonics-based radar system is designed and fabricated for X-band frequency-modulated continuous-wave (FMCW) radar with optical devices, and it is demonstrated by conducting system integration and far-field tests. The photonics-based radar system generates broadband linear frequency-modulated (LFM) signals with a bandwidth that is 20% of the X-band of the center frequency for high-resolution inverse synthetic-aperture radar (ISAR) images by using an electro-optical modulator. It directly processes broadband target signals with photonics devices. To perform a field test using the proposed photonics-based radar transceiver system, the output powers for the long-range and short-range modes were designed to be 7 W and 100 mW, respectively. The far-field test confirmed a detection range of the simulated target with a 10-m2 radar cross section (RCS). A drone ISAR image with a 7.5-cm high-range resolution is achieved by applying broadband LFM signals with a bandwidth that was 20 % of the X-band. The result of this study can enhance the ability to design photonics-based radar systems and assist the development of FMCW radar for detection, tracking, and ISAR images.

Differential coding scheme based FSO channel for optical coherent DP-16 QAM transceiver systems

Abstract This article has indicated optical coherent differential polarization (DP) 16 quadrature amplitude modulation (QAM) transceiver systems with free-space optical (FSO) channel in the presence of differential coding scheme. The optical coherent DP 16-QAM receiver executes the reverse process conversion of the optical signal into an electrical one that is detected to the users. The proposed optical coherent DP-16 QAM transceiver systems based FSO channel model with differential coding has been presented and compared with the previous model. However, the simulation results have confidence realization about the superiority of the proposed simulation model. Hence the proposed optical coherent DP-16 QAM transceiver systems simulation model with differential coding is verified and validated the enhancement performance based on simulation performance parameters.

Different soliton pulse order effects on the fiber communication systems performance evaluation

&lt;p&gt;The study outlined the soliton pulse order effects on the performance efficiency of the optical transceiver systems. The power after fiber is reported for various Soliton pulse order. Max optical signal power (SP) and min optical noise power (NP) are clarified versus time after optical fiber for various soliton pulse order. As well as the max electrical power amplitude against time period is demonstrated after electrical filter for various soliton pulse order. It is reported that the optical transceiver performance efficiency can be upgraded with the first soliton order pulse. The soliton technique is used for high speed communication transmission systems. Soliton technique is used to compensate the dispersion and balanced with nonlinear effects. The soliton order effects is then discussed to choose the suitable soliton order for high speed system performance efficiency. The soliton techniques can be used also for extended ultra high transmion distance with high data rates.&lt;/p&gt;

Dual-Polarized Nonreciprocal Spatial Amplification Active Metasurface

This letter presents a dual-polarized nonreciprocal active metasurface (MTS) for spatial electromagnetic wave amplification. The MTS is designed based on receiving, amplifying, and reradiating scheme. Two square patch antennas printed on the opposite sides of two-layer substrates are used as receiving and reradiating antennas, respectively. A T-shaped microstrip line coupling structure is adopted to achieve impedance matching and dc-block function. Two bipolar transistors, which are place on a pair of orthogonal microstrip feed lines, are used as amplifiers to achieve dual polarization spatial amplification of the electromagnetic wave. A prototype MTS is fabricated and tested to verify the design. The measured effective spatial amplification coefficients higher than 0 dB has a band from 4.88 to 5.19 GHz with the peak value of 10.4 dB. Besides, the proposed MTS is insensitive to polarization. The spatial amplification coefficients variation for different polarization is below 0.6 dB. The proposed MTS could be used in the radio frequency transceiver systems to reduce the pressure of the amplifier on the circuit board.