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This paper provides a comprehensive performance comparison between a current robust military waveform; namely, MIL-STD-188-110D, Waveform 0, and a filter bank multicarrier spread-spectrum (FBMC-SS) waveform proposed for communications through ionospheric/skywave HF channels. Waveform 0 is effectively a direct sequence spread spectrum waveform that uses Walsh multi-codes to enhance the information transmission rate. It may thus be referred to as Walsh-DSSS. FBMC-SS, on the other hand, makes use of filter banks to provide excellent performance when the received signal is subject to partial band interference. Successful application of FBMC-SS for communications across skywave HF channels has been previously demonstrated, both theoretically and through experimental work. However, very little has been done to contrast FBMC-SS against Walsh-DSSS. The goal of this paper is to first add new features to FBMC-SS to bring it on par with Walsh-DSSS. These features include: (i), introduction of multi-codes that achieve a comparable (or better) data rate to Walsh-DSSS; and (ii), addition of a scrambling step applied to the multi-codes to make the receiver detection robust against widely spread multipaths. With this established, in the second part of the paper, we examine the performance of the developed FBMC-SS against Walsh-DSSS when both are applied for communications across skywave HF channels. The two waveforms are compared both through a theoretical study and through experimental works across several skywave channels ranging from hundreds to thousands of kilometers. [ABSTRACT FROM AUTHOR]

In-band full-duplex (IBFD) communications has the potential to nearly double the spectrum efficiency of existing 5G communications. Digital signal processing to mitigate self-interference is one way to realize this full-duplex capability. However, the aggregated wideband nature of 5G coupled with the potential for large delay spreads and short coherence times makes the realistic implementation of such an IBFD processor challenging. In this paper, we address the architectural considerations and describe the practical implementation of a real-time IBFD digital processor and its performance when operating on wideband data collected in a highly dynamic environment.

In this paper a new application for transmitting image notifications on the FM radio broadcasting infrastructure, dedicated to warn drivers about significant road events and to increase the traffic safety is presented. The paper analyzes different technical solutions suitable for transmitting and receiving real-time image notifications in different scenarios by using the software-defined radio concept. In the first scenario, the image notifications are QPSK modulated and transmitted with 8 kb/s bit-rate by using a mono FM radio channel. In order to increase the speed of data transmission, the second scenario uses the FM subcarrier channels dedicated for broadcasting alternate services. In this case, a stereo FM radio channel is used to transmit data with 40 kb/s, 60 kb/s and 80 kb/s bit-rates, by using QPSK, 8-PSK and 16-PSK modulations, respectively. A new software solution to perform the real-time carrier synchronization for 8PSK/16-PSK modulation based on a decision-directed PLL and non-linear decision block is also presented. The functionality of the proposed application was demonstrated by simulations for both transmission scenarios. Moreover, the first scenario was tested experimentally by using a professional FM transmitter and a simple RTL-SDR dongle as receiver. The customized baseband modulating signal including audio, data (image notification) and RDS signals was generated by using a device built by the authors. The receiver provides the digital signal through a USB interface to a software program, running on a processing unit, for demodulation. An experimental method for plotting the bit error rate vs. Eb/N0 ratio, based on signal-to-noise ratio measured with a software spectrum analyzer is also proposed. This method allows the characterization of the data transmissions performed by using an experimental setup and give hints about the QPSK signal power level compared to the other ones (audio and RDS signals).

This work proposes a machine learning detection scheme for wireless orbital angular momentum (OAM) communication systems. The new scheme works for single‐input–single‐output (SISO) and multiple‐input–single‐output (MISO) wireless communication between the transmitter and the receiver. The transmitter encodes its data in OAM modes which are constructed using Laguerre–Gaussian beam form. The transmitted beams travel through a wireless channel with weak to medium turbulence strength and they arrive at random positions on the same receiver area. The authors proposed detection scheme allows the reception of multiple overlapping beams without prior knowledge of beams centre positions. The proposed scheme uses a novel technique of receiver segmentation and space filtering along with neural network to decode the received beams. Simulations show the detection efficiency and the enhanced performance of their proposed scheme for the SISO case and the MISO case with 2, 4, and 16 beams. [ABSTRACT FROM AUTHOR]

Abstract 5G systems and networks are expected to provide unprecedented data-rate to final users and services, in combination with increased coverage and density. The traffic generated at the edges of the network should be hauled through high capacity data-conveyors. Extremely high data-rate links able to provide optical-fiber like performance in the order of 100 Gbps are required to reduce the cost and increase the flexibility of the network infrastructure deployment. This paper presents a full transceiver architecture based on a channel-bonding radio-frequency front-end operating at millimeter-wave frequencies and digital baseband processing units able to provide such data-rates with a feasible implementation in low-cost CMOS technologies. The baseband section of the receiver includes digital compensation algorithms that allow to cope with some of the radio front-end impairments. The main functionalities of the proposed transceiver architecture are validated in hardware.

Multi-node leadless pacemaker system overcomes the main limitations related to lead complications of the conventional cardiac pacemaker and will thus replace them in the near future. The multiple nodes of the technology require the development of low-power, low data-rate and energy-efficient communication framework for device synchronization and bi-directional communication between them. Moreover, the nodes need to communicate with the outer peripheral devices for data telemetry, control and remote monitoring. This paper focuses on evaluation of different energy-efficient modulation schemes at 433 MHz for bi-directional communication between the nodes using homogeneous liquid phantom model of human heart and living animal experiments. In this paper, we have analyzed three simple, low-budget modulation schemes - On Off-Keying (OOK), Frequency Shift-Keying (FSK), and Gaussian Frequency Shift-Keying (GFSK). The analysis is done based on the total transmitter power required to achieve a reliable communication indicated by the minimum threshold values of bit-error rate and packet-error rate. The experiments have been conducted for three common implant communication scenarios - in-body to in-body, in-body to on-body and in-body to off-body links. For conducting the experiments, we have designed the experimental setup with electronic components and fabricated antennas. The results have shown that GFSK has the best performance among the other modulation techniques based on the total transmitter power. We also investigated higher order of the same modulation schemes - 4-FSK and 4-GFSK. The results showed that GFSK performed much better than 4-FSK and 4-GFSK. This research will be carried forward to build the entire radio frequency communication framework for the multi-node pacemaker technology.

This work proposes a machine learning detection scheme for wireless orbital angular momentum (OAM) communication systems. The new scheme works for single‐input–single‐output (SISO) and multiple‐input–single‐output (MISO) wireless communication between the transmitter and the receiver. The transmitter encodes its data in OAM modes which are constructed using Laguerre–Gaussian beam form. The transmitted beams travel through a wireless channel with weak to medium turbulence strength and they arrive at random positions on the same receiver area. The authors proposed detection scheme allows the reception of multiple overlapping beams without prior knowledge of beams centre positions. The proposed scheme uses a novel technique of receiver segmentation and space filtering along with neural network to decode the received beams. Simulations show the detection efficiency and the enhanced performance of their proposed scheme for the SISO case and the MISO case with 2, 4, and 16 beams. [ABSTRACT FROM AUTHOR]

In this paper, we have designed and realized a two‐stage low‐noise power amplifier (LNPA) with resistive feedback network targeting for Ka‐band compact RF front‐end applications. Featuring the characteristics of both low noise and high power at the same time, the LNPA is expected to be a possible one‐chip replacement of power and low noise amplifiers integrated in a conventional transceiver/receiver (T/R) module. Such configuration features size compactness while reduces implementation complexity which is of crucial importance for integration in antenna arrays with large number of antenna elements. Implemented in 0.15‐μm GaAs pseudomorphic high electron mobility transistor (pHEMT) technology, the LNPA, operating at 36–40 GHz, exhibits a peak gain of 15.96 dB, a minimum noise figure of 2.88 dB, a power consumption of 152 mW and a measured 1‐dB compression output power of 14.92 dBm at 38 GHz, respectively. The LNPA also featured a very good linearity performance with a measured output third‐order interception point (IP3) of 22.22 dBm at 38 GHz. [ABSTRACT FROM AUTHOR]

5G systems and networks are expected to provide unprecedented data-rate to final users and services, in combination with increased coverage and density. The traffic generated at the edges of the network should be hauled through high capacity data-conveyors. Extremely high data-rate links able to provide optical-fiber like performance in the order of 100 Gbps are required to reduce the cost and increase the flexibility of the network infrastructure deployment. This paper presents a full transceiver architecture based on a channel-bonding radio-frequency front-end operating at millimeter-wave frequencies and digital baseband processing units able to provide such data-rates with a feasible implementation in low-cost CMOS technologies. The baseband section of the receiver includes digital compensation algorithms that allow to cope with some of the radio front-end impairments. The main functionalities of the proposed transceiver architecture are validated in hardware. [ABSTRACT FROM AUTHOR]

Cognitive radios that are able to operate across multiple standards depending on environmental conditions and spectral requirements are becoming more important as the demand for higher bandwidth and efficient spectrum use increases. Traditional custom ASIC implementations cannot support such flexibility, with standards changing at a faster pace, while software implementations of baseband communication fail to achieve performance and latency requirements. Field programmable gate arrays (FPGAs) offer a hardware platform that combines flexibility, performance, and efficiency, and hence, they have become a key in meeting the requirements for flexible standards-based cognitive radio implementations. This paper proposes a dynamically reconfigurable end-to-end transceiver baseband that can switch between three popular OFDM standards, IEEE 802.11, IEEE 802.16, and IEEE 802.22, operating in non-contiguous fashion with rapid switching. We show that combining FPGA partial reconfiguration with parameterized modules offers a reduction in reconfiguration time of 71% and an FIFO size reduction of 25% compared with the conventional approaches and provides the ability to buffer data during reconfiguration to prevent link interruption. The baseband exposes a simple interface which maximizes compatibility with different cognitive engine implementations.

This article presents the experimental results of 17 MeV proton irradiation on a 60 GHz low power, half-duplex transceiver (TRX) chip implemented in 65 nm CMOS technology. It supports short range point-to-point data rate up to 6 Gbps by employing on-off keying (OOK). To investigate the irradiation hardness for high-energy physics (HEP) applications, two TRX chips were irradiated with total ionising doses (TID) of 74 and 42 kGy and fluence of [inline-formula] and [inline-formula] for RX and TX modes, respectively. The chips were characterised by pre- and post-irradiation analogue voltage measurements on different circuit blocks as well as through the analysis of wireless transmission parameters like bit error rate (BER), eye diagram, jitter etc. Post-irradiation measurements have shown certain reduction in performance but both TRX chips have been found operational through over the air measurements at 5 Gbps. Moreover, very small shift in the carrier frequency was observed after the irradiation.

Rendezvous in the blind fashion is known as one of the most robust and effective ways for cognitive users (CUs) to exchange control information under the dynamic interference of primary users (PUs). Earlier, no existing scheme could guarantee CUs to rendezvous blindly in each timeslot, which makes them experience relatively long exchange delay. Based on the mathematical concept of relaxed cyclic difference set (DS), this paper proposes two novel channel hopping (CH) schemes for multi-radio CUs with and without a synchronized time clock to rendezvous blindly in every timeslot. This achievement of minimum rendezvous delay is especially useful for such delay-sensitive applications as real-time voice and emergency communications. Moreover, based on a special class of DS, the proposed two schemes can closely approach the theoretical lower bound on the number of radio transceivers for CUs to rendezvous blindly in every timeslot and, hence, minimizes their required hardware complexity to exchange control information at the minimum rendezvous delay. Numerical simulation shows that, under dynamic PU interference, the proposed schemes outperform the existing ones in terms of the average throughput and delay of CUs. [ABSTRACT FROM AUTHOR]

A synergetic‐equalisation coding scheme for pulse‐amplitude modulation 4‐level (PAM4) is proposed, based on which a 216 Gb/s 9‐bit 8‐wire 4‐level (9B8W4L) transceiver is designed. According to the scheme, eight channels are grouped into four pairs based on the states for encoding. The two channels in pair transmit the same symbol in this unit interval (UI), and transmit different symbols in different pairs in the next UI. When decoding, the symbols in different channels are subtracted from and added with the others, following the grouping in the prior UI. From this, the first post‐cursor inter‐symbol interference is eliminated. Based on the proposed coding scheme, the PAM4 transceiver transmits 9‐bit data by eight channels, giving a channel utilisation of 112.5%. The improvement of channel utilisation reduces the Nyquist frequency for the same data rate, which is of great significance for reducing channel loss and power consumption. The 216 Gb/s 9B8W4L transceiver with 1‐tap feed‐forward equaliser achieves a bit error rate <10−12 through −20 dB channel loss at the Nyquist frequency of 12 GHz. [ABSTRACT FROM AUTHOR]

A system for local oscillator (LO) signal generation in 5G millimeter-wave (mmW) multi-antenna transceivers is presented. The system is modular with one phase locked loop (PLL) per antenna element transceiver, and a test circuit implemented in 28-nm fully depleted silicon on insulator (FD-SOI) CMOS features two such PLLs and a 491.52 MHz crystal oscillator (XO) generating a common frequency reference. A fractional-N architecture is employed to achieve high-frequency resolution, and the quantization noise is reduced using a novel frequency divider, which achieves full integer resolution while still using a pre-scaler. The system covers the 3rd Generation Partnership Project (3GPP) bands n257 and n258, achieved by a digital coarse tuning of the voltage-controlled oscillator (VCO). The chip area of each PLL is 0.11 mm2, and 0.029 mm2 for the XO. The total power consumption of the system is 35 mW, where each PLL consumes 15.4 mW and the XO consumes 0.84 mW. The total rms jitter from 20-kHz to 500-MHz offset for a 26-GHz carrier is just 115 fs, corresponding to an FOM $_{\vphantom {R_{j}}j}$ of −244 dB, which is the best reported figure for a fractional-N PLL above 15 GHz. The error-vector magnitude (EVM) due to phase noise is −34.6 dBc using an orthogonal frequency-division multiplexing (OFDM) signal with 120-kHz sub-carrier spacing, sufficient to support 256 QAM. [ABSTRACT FROM AUTHOR]

This paper proposes an active radio frequency (RF) cancellation solution to suppress the transmitter (TX) passband leakage signal in radio transceivers supporting simultaneous transmission and reception. The proposed technique is based on creating an opposite-phase baseband equivalent replica of the TX leakage signal in the transceiver digital front-end through adaptive nonlinear filtering of the known transmit data, to facilitate highly accurate cancellation under a nonlinear power amplifier (PA). The active RF cancellation is then accomplished by employing an auxiliary TX chain to generate the actual RF cancellation signal, and combining it with the received signal at the receiver (RX) low-noise amplifier (LNA) input. A closed-loop parameter learning approach, based on the decorrelation learning rule, is also developed to efficiently estimate the coefficients of the nonlinear cancellation filter in the presence of a nonlinear PA with memory, finite passive isolation, and a nonlinear LNA. The performance of the proposed cancellation technique is evaluated through comprehensive RF measurements adopting commercial LTE-Advanced transceiver hardware components. The results show that the proposed technique can provide an additional suppression of up to 54 dB for the TX passband leakage signal at the LNA input, even at very high transmit power levels and with wide transmission bandwidths. Such a novel cancellation solution can, therefore, substantially improve the TX–RX isolation, hence reducing the requirements on passive isolation and RF component linearity, as well as increasing the efficiency and flexibility of the RF spectrum use in the emerging 5G radio networks. [ABSTRACT FROM PUBLISHER]

A fully integrated low‐power 2.4 GHz ZigBee transceiver with inductor‐less radio‐frequency front‐end in 180 nm complementary metal–oxide–semiconductor is presented. The proposed double push–pull low noise amplifier collaborates with a current‐mode down‐converter to provide wideband low‐noise amplification, as well as the out‐of‐band blocker resilience. To save power, a sliding frequency synthesiser (FS) with a low‐frequency running voltage controlled oscillator is employed to provide the local oscillation for both the receiver and transmitter. Measurement results show that the RX reaches −102 dBm sensitivity and dissipates 11 mA power. The FS achieves −91 dBc/Hz in‐band phase noise with only 6.5 mA DC power. The TX features +7.6 dBm maximum output channel power, 4% error vector magnitude at the cost of 19.5 mA power. [ABSTRACT FROM AUTHOR]

In this study, the authors consider robust transceiver design for amplify‐and‐forward relay aided multiple‐input multiple‐output interference systems assuming direct transmitter–receiver links and imperfect channel state information (CSI). The imperfect CSI of each link consists of the estimated channel and the covariance matrix of the channel estimation error. The authors address two transceiver optimisation problems: one is minimising the sum of averaged mean squared error (MSE) at all the receivers and the other is minimising the maximum averaged MSE among all the receivers, both of which are subject to power constraints at the transmitter and relay nodes. The formulated sum‐MSE minimisation and max‐MSE minimisation based optimisation problems are non‐convex with matrix variables and therefore a globally optimal solution is difficult to obtain. To solve these non‐convex optimisation problems, they develop sub‐optimal iterative algorithms based on alternating minimisation approach to jointly optimise the precoding matrices at the transmitter and relay nodes and the receiver filter matrices. Simulation results demonstrate the effectiveness of the proposed algorithms and their improved performance against CSI uncertainties at similar computational cost as the existing non‐robust designs. [ABSTRACT FROM AUTHOR]

Miniaturised transceivers are essential in multiband wireless communication systems for higher data rates and low power consumption. Microelectromechanical system (MEMS) resonator filters are actively considered for deployment in transceivers for radio frequency and intermediate frequency (IF) signal filter and oscillator applications. In this study, the authors propose dual frequency capacitive transduced MEMS resonator with two‐port electrical configuration. Clamped–clamped beam resonator was selected to serve as a basic resonant tank for the filter concept validation. Five design strategies low loss structural material, array design, mixed electrical and mechanical coupling scheme, sub‐micro meter transduction gap and large transduction area were explored. With these strategies, the device achieves dual band filter characteristics, narrow pass band, desired bandwidth, low insertion loss and better stop band rejection. Dual frequency response of the proposed resonator is demonstrated at centre frequencies 400 kHz and 2.57 MHz with a narrow pass band of 3 and 20 kHz, respectively. Low insertion loss of 19.8 and 25.6 dB for frequencies centred at 400 kHz and 2.57 MHz, respectively and stop band rejection >35 dB was achieved. The proposed MEMS resonator may be incorporated in the implementation of dual band pass filter for IF signal filter and dual frequency oscillator applications. [ABSTRACT FROM AUTHOR]

The ubiquitous connectivity of the low-end devices in the Internet of Things (IoT) brings new challenges over the traditional wireless sensor networks’ architectures. Such challenges require not only security and privacy-related features, but also solutions to handle the ever-growing amount of data transferred over the network. However, performing such tasks on resource constrained devices is not straightforward. The need for energy-efficient devices, while preserving their performance and security capabilities, requires new solutions at the architectural level of the wireless device. This paper proposes a heterogeneous architecture that targets low-end and resource constrained IoT devices, combining a hardcore microcontroller unit (MCU) and a reconfigurable computing unit (RCU) with an IEEE 802.15.4 radio transceiver. The MCU hosts an embedded operating system with an IoT-enabled network stack, and exploits the available field-programmable gate array technology to implement the RCU and to deploy customized sensing- and network-related accelerators, offloading heavy, and/or complex software tasks to dedicated hardware blocks. The customizable and trustable end-device mote was implemented using the proposed architecture and the achieved results demonstrates the benefits, both in terms of performance and energy, of accelerating network-related tasks in always-connected resource constrained IoT devices. [ABSTRACT FROM PUBLISHER]

Aggressive power cycling of DC–DC converters is becoming important in many applications ranging from sensor interfaces to wireless transceivers, where the system needs to be on for only short time intervals. In this study, a switching DC–DC converter in a discontinuous‐conduction mode is proposed. The DC–DC converter is well‐suited for light‐load applications and features a very short start‐up time of 330 ns. This short start‐up time makes it suitable for aggressive power cycling, since it can turn on quickly to provide the required voltage for its load. The proposed control loop allows for the short and smooth start‐up behaviour of the DC–DC converter to exhibit no overshoot in the transient output voltage. Experimental results in a 65 nm CMOS show that this DC–DC converter has an efficiency of 72–80.3% for input voltages ranging from 2.4 to 3.4 V and output voltages ranging from 1 to 1.2 V. This is achieved when connected to a light load of 100 Ω, and using relatively small inductor and capacitor values of 200 nH and 40 nF, respectively. [ABSTRACT FROM AUTHOR]

We present a radio system that could be used in millimeter-scale wireless neural implants. The system is RF-powered and demonstrates Mbps data rates required for neuromodulation and recording applications. The radio transmits at 58 Mb/s and receives at 2.5 Mb/s maximum data rates. The transceiver uses a duplexer to achieve full-duplex communication via frequency-division duplexing at 1.74 and 1.86 GHz for TX and RX, respectively. The average power consumption of the transmitter is 93 \mu \textW at 58 Mb/s, while that of the receiver is 7.2 \mu \textW at 2.5 Mb/s. The transceiver was fabricated using 40-nm LP CMOS process and occupies 0.8 mm2 of die area. Including the off-chip duplexer, the system occupies 2 $\times $ 1.6 $\times $ 0.6 mm3. [ABSTRACT FROM AUTHOR]

Speed measurements are crucial for controlling traffic and in supporting automation of industrial processes. The speed of moving objects is typically measured from a stationary position using time‐of‐flight or the Doppler effect. Existing approaches require either relatively bulky physical devices or complex signal processing. The authors propose a new method for measuring the speed of (metal) objects moving on a fixed track. The authors' method is applicable, e.g. to cars on a road, trains on rails, or goods sliding on a conveyor belt. The method relies on the constructive and destructive interference patterns created by the reflections from the moving target. Speed is determined by measuring the signal strength of received messages as perceived by standard wireless devices. The method requires only minimal signal processing and only two commodity wireless transceivers, which are independent of the moving target. The advantages of their system compared to other technologies are reduced size, reduced cost, and in some scenarios robustness. [ABSTRACT FROM AUTHOR]

A low-power frequency modulated-ultra-wideband (FM-UWB) receiver for short-range communications, capable of simultaneously demodulating multiple FM-UWB signals located at the same frequency, is presented in this paper. The proposed receiver utilizes an “approximate zero IF” architecture that uses a low-power, free-running ring oscillator as the RF LO to first convert the input signal into baseband, where it is then amplified and demodulated. Moving the most power-hungry blocks from RF to IF results in reduction of power consumption by more than one order of magnitude compared to previous implementations using the delay-line demodulator. Integrated in a 65-nm CMOS technology, the whole receiver chain consumes 423 \mu \textW from a 1-V supply while achieving −70-dBm sensitivity at a data rate of 100 kb/s at 4 GHz. Communication with up to four FM-UWB users, operating in the same band, is demonstrated, making this receiver suitable for high-density wireless sensor networks. [ABSTRACT FROM AUTHOR]

In this letter, we investigate the detrimental effects of phase noise (PN) and in-phase/quadrature (I/Q) imbalance (IQI) on full-duplex OFDM transceivers. In particular, we derive a closed-form expression for the average residual self-interference (SI) power and show its functional dependence on the parameters of the radio- frequency impairments and channel taps’ power. Moreover, for perfect digital-domain cancellation, we show that the effects of PN and IQI can be approximately decoupled for small PN and IQI levels and the average residual SI is linearly proportional to the I/Q image rejection ratio and PN 3-dB bandwidth. Our numerical simulations validate the accuracy of the derived closed-form expressions and our findings. [ABSTRACT FROM PUBLISHER]

Efficient beamforming of phased-array antennas requires that the phase delay of each channel is accurately known. One technique for achieving this is to distribute a calibration or local-oscillator reference signal through a delay-insensitive signal distribution network. In this paper, we propose using passive hierarchical signal distribution networks to distribute such signals, a method that scales significantly better with the size of the array than existing signal distribution methods. We analyze the impact of impedance variations within the network on the phase accuracy and propose a calibration front-end architecture. This front end also enables the return loss and coupling between antennas to be monitored for diagnostic purposes. We present an implementation of this front end that was applied to a small prototype antenna array, and show that this implementation exhibited low sensitivity to delays within the calibration network, reduced the temperature-dependent phase error of the front ends substantially, and can be used for performing antenna return-loss measurements. [ABSTRACT FROM AUTHOR]

The authors examine a resonant tunnelling diode (RTD)‐based wireless transceiver system in conjunction with radio‐over‐fibre (RoF) and identify the performance limiting factors. Ultra high‐definition television 4K‐video over 1 km fibre and 15 cm wireless is demonstrated. In addition error‐free data transmission up to 11 Gbit/s over 1 km fibre and 10 cm wireless is also presented. Eye‐diagram and jitter results for laboratory RoF equipment show the performance is not degraded with respect to an RTD‐only system, and that RoF‐RTD is considered promising and complementary technologies. [ABSTRACT FROM AUTHOR]

The advancement of embedded technologies has led to increasing demand for bandwidth in telecommunications solutions, this increased the researches related to the architecture of wireless networks and applied electromagnetism. In view of this, the digital transceiver radios need an adequate received signal strength indicator to enable the traffic of information by the radio propagation channel and to provide quality in the data network for the users to exercise the operational activities. The objective of this Letter is to perform the exploratory and variographic analysis of the data collected in the oil fields. Hence, evaluate the behaviour of the surface power distribution received from a wireless system in the frequency range of 5.8 GHz located in the well‐automation region called Canto do Amaro, Brazil, where there are frequent communications failures for mobile stations. With the data measured in the measurement campaigns, variogram models were constructed and compared for the construction of interpolation matrices and contour maps, with these results the precision criteria of the kriging methods employed in the study region were established. [ABSTRACT FROM AUTHOR]

A novel transceiver architecture is proposed to mitigate the phase noise in the prevailing wireless full‐duplex transceivers. In this architecture, an oscillator module is designed to generate both the transmitter and the receiver oscillator signals from one single oscillator. Particularly, a digitally‐controlled delay module is used to control the delay of the receiver oscillator signal before mixing with the received signal at the down converter. By adjusting the delay value of the receiver oscillator signal, the power of residual self‐interference (SI) after digital SI cancellation can be minimised. Analytical and simulation results show that the digital SI cancellation capability of the proposed architecture can be 18 dB better than that of the conventional architecture of sharing one oscillator for transmitter and receiver. [ABSTRACT FROM AUTHOR]

The use of optical transceivers in antenna array system applications requires reliable operation at high temperature. The experimental characterisation of a silicon photonics transceiver operating in a harsh environment with temperatures up to 120°C is presented and discussed. The transceiver was placed inside a climatic chamber and it was fed by an external depolarised light source. The bit error rate was measured, and the impacts on transmission performances were analysed and discussed, including reliability aspects. The authors believe that silicon photonics transceivers with an optimised design and with improvements in the optical connector and fibre adhesive technology are suitable for this kind of applications. [ABSTRACT FROM AUTHOR]

A transceiver pixel for active imaging incorporating a transmitter (TX) and a coherent receiver (RX) is demonstrated in 65 nm CMOS at 260 GHz. The pixel occupies an area of 450 × 580µm2 and is the first demonstration of pixels incorporating a TX and a coherent RX which are smaller than λ/2 × λ/2. The pixel exhibits −21.3 dBm total radiated power and −79.5 dBm sensitivity at a 1 kHz noise bandwidth. This sensitivity is about 10 dB better than the state‐of‐the‐art pixel with only a coherent RX. The pixel consumes 18.7 mW of DC power. [ABSTRACT FROM AUTHOR]

The energy optimisation problem of wireless communications as a power consumption tradeoff between the transmitter and receiver is considered. The goal is finding the right balance between the transmission power and the amount of digital signal processing at the receiver. The problem then consists of deriving the optimal signal‐to‐noise ratio. Receiver cost functions from real implementations are defined and the constrained optimisation problem for single and multiuser links is solved. The numerical analysis shows that there is an optimal ratio between transmission power and signal processing which can lead to a 30% power reduction for noise limited systems. [ABSTRACT FROM AUTHOR]

A hybrid self‐interference (SI) cancellation scheme, composed of a two‐tap analogue canceller and a digital multi‐path SI canceller, is proposed for single‐antenna full‐duplex radios. The analogue canceller mitigates the two strongest components of the SI to prevent saturating the receiver. The digital canceller deploys an auxiliary receiver chain to capture the RF‐transmitted signal to mitigate the residual multi‐path SI signal. As the proposed scheme uses the RF‐transmitted signal as reference, the transceiver impairments such as power amplifier non‐linearities and phase noise are suppressed along with the SI. Experiments have validated the effectiveness of the proposed scheme on a 20 MHz long‐term evolution signal of +20 dBm power. [ABSTRACT FROM AUTHOR]

For mobile user equipments (UEs), a careful power management is essential. Despite this fact, quite an amount of energy is wasted in today's UEs’ analogue (AFEs) and digital frontends (DFEs). These are engineered for extracting the wanted signal from a spectral environment defined in the corresponding communication standards with their extremely tough requirements. These requirements define a worst-case scenario still ensuring reliable communication. In a typical receiving process the actual requirements can be considered as less critical. Knowledge about the actual environmental spectral conditions allows to reconfigure both frontends to the actual needs and to save energy. In this paper, the authors present a highly efficient generic spectrum sensing approach, which allows to collect information about the actual spectral environment of an UE. This information can be used to reconfigure both the AFE and DFE, thus endowing them with increased intelligence. A low-complex multiplier free filter bank extended by an efficient power calculation unit will be introduced. They also present simulation results, which illustrate the performance of the spectrum sensing approach and a complexity comparison with different well-known implementations is given. Furthermore, estimates on the chip area and power consumption based on a 65 nm CMOS technology database are provided, considering the Smarti4G chip as a reference.

The authors evaluate miniature batteries as potential power sources for advanced wildlife telemetry tags. These tags are often based on integrated ultrahigh frequency transceivers that are designed for wireless sensor networks and that consume 18–85 mA while receiving or transmitting. This current drain is challenging for many types of miniature batteries. The authors evaluate batteries both on actual tags and in a specialised synthetic‐load circuit. The evaluation focuses on the total amount of energy that the battery delivers until the tag fails, but the authors also investigate other important issues, such as the ability to withstand immersion in water. The main findings are that zinc‐air cells designed mainly for hearing aids perform extremely well in terms of effective energy density (but are hard to deploy), that lithium coin cells require a reservoir capacitor to deliver their rated energy (which is about half of that of zinc air with the same weight) and that rechargeable lithium polymer cells perform well even without a reservoir capacitor. [ABSTRACT FROM AUTHOR]

In wireless sensor networks, transceiver's utilisation should be minimised as it is the largest power consuming component of a wireless sensor node. In this study, the authors propose a distributive topology‐control algorithm which minimises network's power consumption by allowing the non‐relay nodes in the data dissemination tree to switch‐off their respective transceivers when communication is not desired. In this algorithm, named duty‐cycle SN‐multi‐point relay (MPR), the sink follows a sojourn‐based mobility model and it uses MPR broadcast algorithm for broadcasting its periodic sink location update packets to the network which results in a tree consisting of relay/MPR and non‐relay/non‐MPR nodes. Duty‐cycle SN‐MPR algorithm minimises power consumption by allowing the non‐relay nodes to switch‐off their transceivers in each sink sojourn round. Moreover, all nodes switch‐off their transceivers when the sink starts moving to its next sojourn position. Performance evaluation through simulations in network simulator 2 show that the proposed algorithm efficiently minimises the network's power consumption and also offers a better load distribution which helps in increasing the network lifetime. [ABSTRACT FROM AUTHOR]

A fully integrated 802.11ad/WiGig compliant 60 GHz transceiver is presented in a 130 nm SiGe BiCMOS technology. Encompassing an area of 2.3 mm\, \times \,2.16 mm = 4.97 mm^2, the transceiver covers the entire 60 GHz band, from 57 to 66 GHz. Within this span, the RX NF, TX OP1dB, and PLL RMS jitter is better than 5.5 dB, + 13.5 dBm, and 7^\circ, respectively. The transceiver is packaged in 1) a system-in-package substrate with industry standard WR-15 transition providing an approximate 1 dB insertion loss, and 2) a cost-effective 7\, \times \,7 mm^2 organic BGA package with integrated transmit and receive antennas providing 8 dBi gain. In system-level testing, the transceiver is fully compliant with all TX EVM and RX sensitivity requirements of the WiGig standard up to the top-rate 16-QAM operating mode and across all standard channel frequencies. Link testing over the air with the antenna-integrated package shows a range of 5.9 m at 4.6 Gbps and over 20 m at 2.5 Gbps. This system achieves the highest performance 802.11ad/WiGig compliant wireless links of any reported single-element transceiver. [ABSTRACT FROM PUBLISHER]

Energy harvesting is an emerging solution to prolong the lifetime of energy-constrained nodes in wireless networks. This letter develops a novel distributed energy beamforming scheme for realizing simultaneous wireless information and power transfer in the two-way relay channel (TWRC), where two source nodes exchange information via an energy-harvesting relay node. We investigate the optimal transceiver design to maximize the achievable sum-rate of the TWRC. We also propose a low-complexity power-splitting based suboptimal scheme with closed-form solution. Numerical results demonstrate significant performance improvement of the proposed schemes over the conventional power-splitting based scheme. [ABSTRACT FROM AUTHOR]

This paper describes a fractional-N subsampling PLL in 28 nm CMOS. Fractional phase lock is made possible with almost no penalty in phase noise performance thanks to the use of a 10 bit, 0.55 ps/LSB digital-to-time converter (DTC) circuit operating on the sampling clock. The performance limitations of a practical DTC implementation are considered, and techniques for minimizing these limitations are presented. For example, background calibration guarantees appropriate DTC gain, reducing spurs. Operating at 10 GHz the system achieves −38 dBc of integrated phase noise (280 fs RMS jitter) when a worst case fractional spur of −43 dBc is present. In-band phase noise is at the level of −104 dBc/Hz. The class-B VCO can be tuned from 9.2 GHz to 12.7 GHz (32%). The total power consumption of the synthesizer, including the VCO, is 13 mW from 0.9 V and 1.8 V supplies. [ABSTRACT FROM AUTHOR]

This study presents a smart volt/VAR control (VVC) technique for smart distribution systems, which is designed to be integrated into a distributed real‐time analysis and control framework implemented with the use of multiple processing units equipped with wireless communication transceivers. The distributed processing units collaborate to perform power flow analysis based on smart meter measurements for controlling and coordinating the switched capacitor banks and voltage‐regulating transformers. The objective is to maintain acceptable voltage levels along the distribution feeder, minimise system losses, and limit the number of switching operations. GNU‐Octave simulations are employed as a means of evaluating the performance of the proposed smart VVC technique with respect to loss reduction and number of switching operations. The network simulator ns‐3 is used to simulate the distributed processing units that execute the proposed smart VVC technique. Worldwide interoperability for microwave access (WiMAX) and long‐term evolution (LTE) communication networks are employed in the ns‐3 simulations in order to provide data connectivity among the distributed processing units. The performance of the communication network is evaluated in terms of the execution time of the smart VVC technique, the average packet delay and the average packet delivery ratio. [ABSTRACT FROM AUTHOR]

We consider networked control of luminaires to adapt illumination in an indoor environment to occupancy and daylight based on distributed light-harvesting wireless sensing modules. Each light-harvesting wireless sensing module consists of an occupancy sensor, a light sensor, a wireless radio, a microcontroller unit, and a photovoltaic cell. The occupancy sensor and light sensor, respectively, determine presence and illumination level within their fields-of-view. This local sensor information, along with control information from neighboring sensing modules, is used by a local controller to determine the dimming level of its luminaire so as to achieve its reference setpoint. To realize this system, we propose a low-power wireless sensing protocol and a neighbor-aided illumination control method considering the harvesting constraints of the sensors. The proposed methods are implemented in an indoor lighting system testbed and the performance is shown to meet desired illumination conditions. [ABSTRACT FROM PUBLISHER]

Body sensor networks with a central gateway node can control wireless transmission and optimize the network lifetime. The central node should be placed within communication reach of other nodes spread out around the human body, such as on the chest. This paper reports a novel energy-efficient time multiplexing transmission method based on the human rhythmic movement of running for on-body wireless communication. The running style of each individual allows the network to self-calibrate the communication scheme so that transmissions occur only when high link reliability is predicted. This technique takes advantage of the periodic running actions to implement a dynamic time division multiple access strategy for a five node body network with very little communication overhead, long sleep times for the sensor transceivers, and robustness to communication errors. The results showed all wireless communications were successful, except when two nodes attempt to use the transmission medium simultaneously. An aggregated network reliability of 90% was achieved compared to 63% when employing traditional time multiplexing algorithms. [ABSTRACT FROM PUBLISHER]

Convergecast, in which packets originating from multiple sources are reported to a single sink, is a fundamental primitive for data collection in wireless sensor networks. This paper investigates the time-optimal link-scheduling problem for time-division multiple-access (TDMA)-based convergecast, aiming to minimize the amount of time required to complete convergecast. We observe that packet copying between the microcontroller and the radio transceiver in existing sensor platforms has a big impact on the packet forwarding delay, and we propose a novel model for convergecast in which packet copying is separated from packet transmission and reception. We establish tight lower bounds on the number of time slots required for convergecast in networks with line and tree routing topologies, and we present both centralized and distributed algorithms for constructing the time-optimal convergecast schedules. We evaluate our scheme in both simulations and experiments on hardware. The results show that our scheme can achieve a system throughput (defined as the number of data bits received by the sink per second) of 202.8 kb/s, which is 86.31% of the theoretical bound. In comparison with the traditional TDMA-based convergecast schemes, our scheme can achieve up to a 86.22% improvement on system throughput. [ABSTRACT FROM PUBLISHER]