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During the first shockwave of the Covid-19 pandemic, the risk of infection was inaccurately touted as ‘the great equaliser’. However, the virus’ rapid spread and the state of emergency accelerated the magnitude of pre-existing inequalities by taking a heavy toll on already marginalised, exploited and extremely poor segments of societies. Focussing on sub-national contexts in Bulgaria and Kosovo, this article demonstrates how Bulgarian Roma and Kosovo Serbs were not only hit the hardest by the introduction of ad hoc lockdowns and curfews, respectively, but also how disciplinary mechanisms of control and surveillance were embedded in public methods and cultural policies of scapegoating and ascribing images of societal irresponsibility and backwardness upon these two minority groups. Keywords: Bulgaria; Kosovo; minority groups; pandemic; ad hoc restrictions; stigmatisation

Standing at 24% in 2018, India’s female labour force participation is only half of the global average (48%). At the same time, India has one of the widest gender wage gaps in the world and women are less likely to be employed in the formal sector compared to men. This article focuses on how international trade affects relative wages and formal employment between men and women in India. Using the Revealed Symmetrical Comparative Advantage index, sectors of comparative advantage and disadvantage are identified and matched to Indian labour force surveys that contain information on sectoral employment and earnings. We find that sectors of comparative advantage in services have the lowest gender wage gap, with women earning 24% less than their male counterparts, while women in manufacturing earned on average 40% less than male workers. Using the Oaxaca–Blinder decomposition, we find that the total gender wage gap in sectors of comparative advantage in services are minor while it is quite substantial in manufacturing, regardless of comparative advantage status. The article concludes that services trade goes hand in hand with a smaller gender wage gap as women leverage their skills better in services than in manufacturing. JEL Codes: F16, F14

The traditional pure switched-capacitor equaliser brings the large inrush current and low energy density. This study proposes a series of resonant switched-capacitor (ReSC) voltage equaliser, which realises energy transferred directly from source cells to target cells by the series ReSC converter. The ReSC converter eliminates the inrush current and improves the capacitors’ energy density to increase the balancing speed. Meanwhile, all the switches are controlled by a pair of complementary PWM signals at a fixed operational frequency without voltage monitors. Both simulation and experiment are used to verify the system feasibility and theoretical analysis of the proposed circuit. In the same experimental condition, the proposed series resonant circuit reduces the inrush current. It improves the energy density of capacitors three times compared with the pure series switched-capacitor equaliser.

It is more convenient and safer to employ wireless power transfer (WPT) systems to charge the battery pack of electric scooters (ESs) than conventional plug-in systems. A charging equaliser suitable for ESs is proposed to achieve constant current (CC) output without communication link between the transmitter side and the receiver side. The full-bridge rectifier and select switches utilised at the receiver side are employed to be operated once to change from the balancing mode to charging modes. The characteristics of the load-independent current output in the CC mode are achieved by properly selecting the parameters of the circuit so that no sophisticated control strategies are required to regulate the output as per the charging profile. The experimental results show that when the voltage of battery pack is charged at 32 or 4.2 V, the current is 1.02 or 1.12 A, respectively. Therefore, the proposed system can be considered as a CC system.

In wireless radio communication systems, equalisation is one of the most important algorithms to improve the bit-error-rate performance. The linear zero-forcing equalisers suffer from noise enhancement. The linear minimum mean square error equalisers suffer from large complexity and require the estimation of the signal-to-noise ratio to work properly. In this study, the authors propose a joint low-complexity regularised zero-forcing equaliser with successive interference cancellation (JLRZF–SIC) based on discrete cosine transform (DCT) for orthogonal frequency division multiplexing (OFDM) systems. The proposed JLRZF–SIC scheme jointly performs the equalisation and carrier frequency offset (CFO) compensation with lower-complexity using the banded-matrix approximation concept. Simulation results show the important role of the proposed JLRZF–SIC scheme is to improve the system performance compared to the other equalisation schemes.

This article investigates the effect of hydrogen aqua equaliser (HAE) with hydrogen repository tank and fuel cell (FC) as an energy storage element for frequency control in an interconnected power ...

Faster-than-Nyquist (FTN) signalling is regarded as a promising technology in satellite communications for the past few years, however, existing inter-symbol interference (ISI) elimination algorithms for FTN signalling cannot eliminate the linear distortion caused by the input-multiplexing and output-multiplexing filters, which are very common in satellite communications. On the strength of the fractionally-spaced equaliser (FSE), the authors propose a precoding-based frequency-domain linear distortion equaliser (PFLDE) to eliminate the above-mentioned linear distortion in FTN systems. On the one hand, by virtue of fast Fourier transform (FFT) and inverse FFT, the proposed PFLDE lends itself naturally to high-throughput parallel architectures, which are quite essential in high throughput satellite communications. On the other hand, the mean square error performance of the proposed PFLDE is superior to that of the existing time-domain FSEs. Furthermore, combining PFLDE with the existing ISI elimination algorithms for FTN signalling, the satisfactory bit error ratio performance can be obtained.

This study accessed the performance of the four-level Manchester coding (4-MC) and four-level modified Manchester (4-MM) technique at the bit rates of 20 and 40 Gb/s for the first-order and second-order optical equalisers. The performances were evaluated with respect to bit error rate (BER), power penalty, eye diagrams, and dispersion tolerance. Based on the results by utilising the second-order optical equaliser, at 20 Gb/s, the transmission distance of 4-MC and 4-MM was extended by 25 and 27 km of standard single-mode fibre (SSMF), respectively, while at the bit rate of 40 Gb/s, the 4-MC and 4-MM transmission distance was extended by 6.5 and 7.5 km of SSMF, respectively. Hence, the second-order optical equaliser can adequately compensate for the fibre dispersion and consequently the overall BER performance. Therefore, the proposed system could serve as an alternative to the next-generation high-speed optical transmission links.

This work presents an analogue equaliser with digital tuning. It compensates the losses introduced by up to 120 m long category 5 unshielded twisted pair cables and baseline wander (BLW). The equaliser is designed for Fast Ethernet with a symbol rate of 125 MHz. A g m -C filter, based on three first-order high pass filters, is used to compensate the cable loss. To minimise power consumption, three operational transconductance amplifiers (OTAs) are merged into a novel multi-input OTA structure. Additionally, a robust digital control logic is presented to automatically adjust the parameters of the equaliser for different cable lengths. A fast settling time below 250 µs is demonstrated for different scenarios. The equaliser is fabricated as part of a Fast Ethernet PHY chip in a 180 nm CMOS technology of GLOBALFOUNDRIES. Measurement results demonstrate error-free data transmission (bit error rate below 10 −12 ) for cable lengths up to 120 m. The power consumption of the analogue equaliser ranges from 2.3 mW (short cable) to 6.5 mW (120 m cable). To the best of the authors’ knowledge, this is the lowest power consumption of an analogue equaliser for Fast Ethernet, supporting additional BLW and flat loss compensation reported to date.

This study presents a fuzzy neural network based non-linear equaliser to diminish the non-linearities in a coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. The numerical results show that the proposed technique based CO-OFDM system outperforms the CO-OFDM system without non-linear equaliser by 5 and 7.5% EVM performance, and 2.36 and 4.87 dB Q-factor performance after 1000 km transmission and −3 dBm input launch power at a bit rate of 40 and 80 Gbps, respectively. Moreover, it has been generally accepted in statistics that the rank-based Wilcoxon methodology provide more robust results in a contradiction of outliers. Therefore, the aim of this study is to analyse fuzzy neural network based non-linear equaliser and compare the results with that of Wilcoxon approach fuzzy neural network based non-linear equaliser.

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

This article presents the body channel communication technique that first adopts decision feedback equalisation. For the first time, we characterised post-cursor intersymbol interference of a single-bit pulse response of a human body channel for decision feedback equalisation achieving the first body channel communication faster than 100 Mb/s. In the proposed technique, an 8-tap decision feedback equaliser is utilised at the receiver to compensate for intersymbol interference of the body channel. The experimental results show that the proposed prototype transceiver achieved the highest data rates of 150 Mb/s and 10 Mb/s along 20-cm and about 100-cm body channels, respectively. Compared to the previous best result measured for the same body-channel distance of about 100 cm, the data rate is improved by ten times, showing that the proposed technique can significantly increase the speed of body channel communication.

Identification of modulation and space-time block code (STBC) is an important task of receivers in applications such as military, civilian, and commercial communications. Here, we consider multiple-input multiple-output (MIMO) systems. We propose two methods for STBC identification when the modulation is known. We also introduce a method for joint identification of code and modulation. Additionally, we present an enhanced zero-forcing (ZF) equaliser to improve the separation between the features of different classes. Higher order cumulants are used as the statistical features. In the first method of STBC identification, after the proposed equalisation, received data samples are segmented, and then using the mean and Frobenius norm of the covariance matrix of extracted cumulants as threshold values, the STBCs are detected. This method requires the knowledge of the threshold values for each modulation type and noise power. In the second method, the knowledge of noise power and the type of modulation are not needed. After the proposed ZF equalisation, feature vector based on the cumulants is calculated, and then support vector machine (SVM) classifier is used to classify different STBCs. In the third method, joint detection of STBC and modulation type is performed using the proposed ZF equaliser and mapping the received samples. This method deals with the theoretical values calculated from the cumulants of four STBCs and four modulations, where there is no need to know the noise power. The results indicate that the proposed methods perform well even at low signal-to-noise ratios (SNRs).

This study presents an adaptive data-transition decision feedback equaliser (DT-DFE) with a sign 3 least-mean-square (LMS) tap adaptation. Commonly used data-state (DS) DFE suffers from reduced vertical eye-opening when consecutive 1's or 0's are encountered. The proposed DT-DFE performs DFE only when a data transition is detected. It boosts the eye-opening of the high-frequency components of data without attenuating the low-frequency components of data whereas DS-DFE boosts the eye-opening of the high-frequency components of data at the expense of the attenuated low-frequency components of data. The reference voltages of DS-DFE is tap-dependent whereas those of DT-DFE are tap-independent and are obtained by conveying consecutive 1's and 0's to the channel in a training phase. The proposed DT-DFE utilises loop unrolling to detect the occurrence of data transition. The performance of the proposed DT-DFE is compared with that of DS-DFE using two 5 Gbps backplane serial links designed in a TSMC 65 nm CMOS technology. Simulation results demonstrate that the eye-opening of the link with DT-DFE is 1.54 times that with DS-DFE. The vertical eye-opening of the link with DT-DFE activating tap adaptation on two consecutive state transitions of opposite polarities is 1.2 times that that activates tap adaptation on single state transition. The proposed DT-DFE is less sensitive to process uncertainty whereas DS-DFE is prone to process uncertainty with severely deteriorating performance.

Ensuring equal access to a broad and balanced curriculum for all students is a key component of a socially just education system. Yet in England, the freedom that 16-year-old students have to choos...

This study proposes an automatic cell-to-cell equaliser to balance the battery voltages in series-connected battery strings. In the proposed equaliser, each cell needs only one MOSFET, and the adjacent cells share the transformer winding. The voltage balance is automatically realised by using a pair of complementary control signals with a fixed duty cycle. What's more, no sensing circuit is required. Consequently, the proposed equaliser is cost-effective and easy-to-realise. The circuit topology and operating principles are firstly presented. Then the voltage balance analysis is given in detail. Moreover, a design guide is also given by considering four lithium-ion cells. Finally, the validity of the proposed equaliser is verified by experimental results.

This study develops a novel equaliser by combining wireless power transmission (WPT) and switch array for series-connected batteries. The physical isolation achieved by WPT can offer unique benefits that traditional equalisers can hardly provide. Parameters of the WPT system are properly designed to achieve an equivalent constant-current output, which can maximise the speed of balance and ensure the health of batteries. This methodology can ensure each battery is connected independently to the inverter through the switch array circuit. Therefore, balancing for either a single battery or multiple batteries can be achieved. In the experiment, the prototype system is built. Experimental results show that the proposed equalisation system can achieve high overall system efficiency (above 87.2%) when balancing four series-connected battery modules.

Radio-over-fibre (RoF) systems consist of two subsystems including optical subsystem and wireless radio frequency subsystem. It is shown that by using multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) systems, the RoF transmission can be improved in frequency-selective channels. In this study, two different configurations of MIMO–OFDM-based RoF systems are compared for the long-term evolution standard under different non-linearity levels, bandwidths, and fading channel conditions. Using the total degradations (TD) criterion, an appropriate quiescent point is determined to decrease the impact of non-linearity level, and hence the performances of different MIMO detection methods are compared. Bit error rate results demonstrate that by using Hammerstein type equaliser, the system performance is improved under different conditions including different fading channels, Doppler frequencies, bandwidths, and output back off levels. Results demonstrate that with an appropriate structure for MIMO–OFDM–RoF systems, a suitable quiescent point can be found for all scenarios by employing Alamouti coding and Hammerstein equaliser.

This paper proposes the fuzzy logic equaliser (FLE) for the detection of non-linear perpendicular magnetic recording (PMR) channels. The multi-objective genetic algorithm (MOGA) is utilised to optimise all of the fuzzy parameters and reduce the complexity while maintaining the accuracy. By means of this optimisation, the total number of fuzzy rules is significantly reduced about 44%. The bit error rate (BER) performance of the proposed FLEs are compared with those of the conventional detector and traditional non-linear equalisers for Volterra channel, in presence of non-linear amplitude distortions in high-density PMR channels. The proposed FLE outperforms existing detectors by 1 to 12 dB SNR gains. Furthermore, the complexity in terms of multiplication counts per execution and reliability of detectors with regard to the number of system parameters through the Akaike's information criterion (AIC) are assessed to verify the effectiveness of the proposed FLEs. An extension to PMR channel with jitter noise proves the robustness of the proposed FLEs.

In this study, a new bidirectional charge equaliser for series-connected cells is proposed to equalise the charge of N series-connected cells in static and dynamic states, i.e. while charging, discharging and when charger/load is disconnected. The proposed topology consists of three parts: a multiplexer, H-bridge and transformer. The multiplexer section connects the target cell to the transformer. The transformer acts as temporary energy storage and the H-bridge section sets the polarity of the voltage on the primary of the transformer. In charging/static mode, the energy transfers from charger/string to the low-charged cell and in discharging mode energy transfers from the cell with the highest charge to the load. In fact, energy transfer is in the same direction as the circuit operation, in this way, the speeds of charge and discharge of series cells are increased. Also due to the existence of only one small transformer and totem-pole arrangement of bidirectional switches, which halved the switch drivers, the cost and size of the circuit is reduced. A prototype of the proposed circuit to balance the charge of four series lithium–ion battery cells is designed and implemented. The experimental results confirm the correct operation of the circuit in all three states.

Conventional battery/super-capacitor (SC) cell voltage equalisers require numerous switches and/or a multi-winding transformer, which are not desired in terms of circuit complexity and extendibility. In this study, a modularised non-isolated two-switch cell voltage equaliser for series-connected lithium-ion battery/SC is proposed. The proposed equaliser consists of a non-isolated front-end dc–dc converter and a full-wave voltage multiplier circuit. Without coupled-inductor, multi-winding transformer and multiple active switches, the proposed equaliser uses only two active switches and two magnetic components, thus it benefits from reduced complexity and circuit volume. Meanwhile, the modularised full-wave voltage multiplier circuit makes it flexible to extend to more battery/SC cells. Furthermore, it can work under open-loop without cell monitoring circuit, which makes its control simple. The equalisation current of the proposed equaliser can be limited automatically. Compared with conventional non-isolated equalisers using half-wave voltage multiplier, it benefits from faster equalisation speed and lower equalisation loss. High efficiency is achieved by zero voltage switching of all switches. Experimental results are provided to verify analysis results of the proposed equaliser.

Dirty paper coding (DPC) is a non-linear transmit scheme in presence of known interference, which is capacity achieving. Unfortunately, the implementation complexity of DPC is usually prohibitive. A sub-optimal yet practical method to implement DPC in inter-symbol interference channels is Tomlinson-Harashima precoding (THP). However, THP is not applicable to the constant-envelope phase shift keying (PSK) modulation. In this study, a modified Tomlinson-Harashima precoder is proposed to implement DPC for PSK modulation. The technique involves design of decision region at the receiver side and an algorithm to select the phase of transmitted symbol optimally at the transmitter side accordingly. Various patterns, namely, striped, checked, hexagonal, and radial are proposed and examined. Simulation results show that by using the proposed equaliser, the error floor is eliminated and significantly smaller bit-error rate is achieved. Numerical and simulation results show that the striped pattern outperforms other decision region designs. Moreover, its implementation and computational complexities is almost the same as the Tomlinson-Harashima precoder.

Deep-sea hydrothermal source investigation utilising water and gas samples to characterise ocean resources requires water sampler, both large and small volume. How to preserve the original captured...

An emerging narrowband radio technology named narrowband Internet of Things (NB-IoT) based on cellular communications has been standardised by the 3rd Generation Partnership Project in release-13. It is specifically designed to provide low-power wide-area connectivity for the IoT. In this study, the authors derive an analytical signal model for Long Term Evolution (LTE)-based uplink NB-IoT systems. The problem of channel equalisation for the uplink NB-IoT systems having mismatched baseband processing and sampling rate between transmitter and receiver is addressed. A relation between the channel impulse response and the channel frequency-domain equalisation coefficients is derived under imbalanced baseband processing and sampling rate environment. Accordingly, a novel one-tap frequency-domain channel equalisation algorithm specific to NB-IoT uplink systems is proposed based on the resultant channel coefficients. Comprehensive link-level simulations are carried out to validate the potentiality of the proposed equalisation method, compared with other conventional techniques like zero forcing and minimum mean square error equalisers in terms of symbol error rate and throughput against signal-to-noise ratio. Simulation results indicate that the proposed equaliser outperforms the existing linear equalisers for all cases of evaluation.

Channel equalisation performs a crucial role in practical wireless communication environment to reduce the consequence of intersymbol interference (ISI), noise and other channel distortions. Different adaptive signal processing algorithms tuned by multiple effective weight update mechanisms have been proposed and verified for designing the channel equaliser. In this paper, a sparse-based reweighted zero attracting incremental least mean square/fourth (ILMS/F) algorithm is anticipated to model an efficient adaptive decision feedback channel equaliser by taking the quadrature amplitude modulation (QAM)-modulated signal as transmitted signal which is passed through a nonlinear channel. The performance of the equaliser based on the proposed sparse-based ILMS/F has been analysed by using software and hardware platforms. The mean square error (MSE) table and bit error rate (BER) plots of the proposed algorithm have been compared with different conventional algorithms using MATLAB simulation and the hardware implementation of the proposed equaliser by using the FPGA platform has been evaluated in this paper. Moreover, the FPGA implementation of the proposed sparse incremental least mean square/fourth (ILMS/F) algorithm validates the robustness of the algorithm.

The Post Correspondence Problem is a classical decision problem about equalisers of free monoid homomorphisms. We prove connections between several variations of this classical problem, but in the setting of free groups and free group homomorphisms. Among other results, and working under certain injectivity assumptions, we prove that computing the rank of the equaliser of a pair of free group homomorphisms can be applied to computing a basis of this equaliser, and also to solve the “generalised” Post Correspondence Problem for free groups.

This paper proposes a cyclic prefix (CP) free spectral efficiency frequency division multiplexing (SEFDM) wireless signal transmission and reception method based on alignment signal (AS). The method needs the cooperation of both the transmission and reception sides. At the transmitter, time-domain AS is designed to prevent inter-symbol interference (ISI) caused by multipath propagation in the received signal. At the receiver, the channel circularity convolution providing processing is used to enable high accurate frequency domain one-tap equaliser. The extensive computer simulation results under the 5G new radio (5G-NR) channel model, TDL-D, show the that the AS aided SEFDM has similar bit error rate performance as CP-SEFDM without energy and latency cost on CP. The AS-SEFDM capability to mitigate the ISI and to enable the one-tap equaliser in SEFDM systems makes it a promising technique for future wireless communication systems. acceptedVersion

International audience; Visible light communication (VLC) systems are highly constrained by the limited 3-dB bandwidth of light-emitting diodes (LEDs). Analogue pre-equalisers have been proposed to extend the LED's bandwidth at the cost of reduced signal-to-noise ratio (SNR). Compared with the pre-equaliser, the multi-carrier modulation with bit-loading can efficiently use the spectrum beyond the LED's raw 3-dB bandwidth without incuring SNR penalties by employing multiple narrow quasi-flat sub-bands to eliminate the need for equalisation. In this work we show by means of theoretical and experimental investigation that VLC with multi-band carrierless amplitude and phase modulation with bit-loading can outperform VLC with analogue pre-equalisers.

In optical camera communication (OCC) systems leverage on the use of commercial off-the-shelf image sensors to perceive the spatial and temporal variation of light intensity to enable data transmission. However, the transmission data rate is mainly limited by the exposure time and the frame rate of the camera. In addition, the camera’s sampling will introduce intersymbol interference (ISI), which will degrade the system performance. In this paper, an artificial neural network (ANN)-based equaliser with the adaptive algorithm is employed for the first time in the field of OCC to mitigate ISI and therefore increase the data rate. Unlike other communication systems, training of the ANN network in OCC is done only once in a lifetime for a range of different exposure time and the network can be stored with a look-up table. The proposed system is theoretically investigated and experimentally evaluated. The results record the highest bit rate for OCC using a single LED source and the Manchester line code (MLC) non-return to zero (NRZ) encoded signal. It also demonstrates 2 to 9 times improved bandwidth depending on the exposure times where the system’s bit error rate is below the forward error correction limit. published

When oriented to the needs of the future fifth generation (5G) networks, orthogonal frequency division multiplexing (OFDM), as a modulation scheme, has some drawbacks: high out-of-band emission (OOBE) of power, relatively low spectrum efficiency, and poor flexibility for allocating resources. In this study, a subband superposed OFDM (OFDM) scheme, based on a variable granularity spectrum allocation, is proposed to divide the transmission channel into several subbands considering the compromises between single-carrier and multicarrier spectrum utilisation. For accommodating the diverse 5G scenarios, appropriate signalling parameters can be independently configured among the subbands. A multistage polyphase interpolator is developed in the transmitter to reduce the implementation cost of time-domain filter depressing the OOBE. Extremely narrow frequency guard intervals between subbands are realised by filtering to maximise the spectrum utilisation. At the receiver, a subband decision feedback and feedforward equaliser, relying on the subband's oversampling architecture, is designed to utilise the diversity gains in both the Doppler and the multipath delay domains. Simulation results indicate that the spectral efficiency, in terms of the spectrum utilisation rate, is increased up to 98.5 % and that the bit-error-rate performance is significantly improved for the subbands experiencing high-speed mobile channels while preserving a relatively low computational complexity.

This paper introduces the logging cable equaliser. In logging engineering, the seven-core cable has been widely used as transmission medium, which has a narrower effective bandwidth. In order to improve the data transfer rate, it is necessary to expand the effective bandwidth. We have proposed a design method of equaliser based on Chebyshev polynomial in this paper. This scheme could compensate the high-order channel attenuation and expand the effective width with lower-order Chebyshev polynomials. The equaliser could also compensate the phase shift of the transfer data which is caused by the non-linear characteristic of logging cable. We have also simulated the scheme with Matlab and produced the circuit board to demonstrate the practical application effect. It is proved that for the non-linear logging transmission channel, the proposed scheme has a good effect on the expansion of the effective bandwidth. It could provide enough bandwidth to enhance the data transmission rate.

This study presents the external modulation and direct detection of duobinary signal in optical access networks at 25 and 50 Gb/s with the use of first-order optical equaliser at the transmitter output (pre-equalisation) to compensate the waveform distortion induced by fibre dispersion. The first-order optical equaliser is then replaced by second-order optical equaliser to further improve the bit error rate (BER) performance and extend the maximum transmission distance by compensating the residual dispersion for the first time. The authors explain the enhancement in the BER by analysing the eye diagrams and optical spectra. The authors also investigate non-return-to-zero signal with similar setup parameters for reference.

Wireless body area communication technology is attracting much attention in healthcare and medical applications. For reliable and high-speed implant transmission, the authors previously developed an in-body transceiver at around 30 MHz. However, as the distance between the transmit antenna and the receive antenna gets longer, its bit error rate (BER) performance gets deteriorated. This is because that an implanted channel can cause severe waveform distortion and consequent inter-symbol interference (ISI). Meanwhile, the equalising technique provides a powerful means to counteract ISI. In this study, they developed an automatic equaliser for the 30 MHz band implant communication. Moreover, they implemented the equaliser on a field programmable gate array board and evaluated the BER performance with a biological equivalent liquid phantom. The measurement result shows that their developed equaliser can significantly improve the communication performance in the implant channel.

In this study, a performance comparison of fibre non-linearity mitigation is performed in the context of 10 and 20 Gb/s coherent optical orthogonal frequency-division multiplexing and wavelength division multiplexing (CO-OFDM-WDM). The authors compare two regression methods based on the third-order Volterra series and least mean square algorithm in terms of the bit error rate (BER) for different transmission distances and modulation formats. They also evaluate the BER as a function of the number of OFDM subcarriers for the Volterra-based non-linear equaliser (VNLE). In addition, by increasing the order of the VNLE from third-order to fifth-order series, a significant increase of performance is obtained for 100 Gb/s CO-OFDM-WDM system. Likewise, a comparison study of 16-QAM 40 Gb/s CO-OFDM system is performed as a function of Q-factor for support vector machine, Volterra equaliser and linear equaliser, respectively.

It is essential for electric vehicle to equalise the voltages of battery or supercapacitor (SC) cells in series connection. Comparing with other equalisation methods based on energy transfer, Cockcroft–Walton (CW) voltage multiplier brings great benefits to the simplification of equalisation structure. Voltage equaliser formed by voltage multiplier can realise voltage balance automatically without voltage detection and control unit. However, the traditional (CW) voltage multiplier structure has two demerits. One is incapable of realising the voltage balancing for all the cells in series; the other one is the large inrush current of parallel capacitors that reduces the lifetime of the equaliser. To solve these problems, a modified voltage equalisation circuit is proposed. The new equaliser is constituted by a half-bridge frontend and a multiplier backend. The half-bridge generates the alternating voltage, and the multiplier accomplishes the voltage balancing. The operation principles, circuit analysis and parameters calculation are examined in detail. The performance is evaluated by simulation and experimental with three SCs in series. The accordance between simulation and experiment further proves that the voltage balancing is achieved for all the series cells and the inrush current of capacitors is declined at the turning on of power switches.

In this paper, we give some categorical objects of racks such as product, pullback and equalizer objects.

The authors investigated the problem of overestimation with the Volterra series transfer function (VSTF) and an artificial neural network (ANN), which are used for non-linear equalisers in optical communication systems. The results revealed that the risk of predicting a pseudo-random binary sequence (PRBS) pattern, which causes overestimation of the equaliser performance, occurs not only with an ANN but also with the VSTF. When using PRBS9, PRBS11 and PRBS15, the number of taps of a feedforward tapped delay line, which is required in the VSTF to predict the PRBS pattern, was the same as that with the ANN. When the second-order Volterra kernels were omitted, a larger number of taps was required in the VSTF to observe the overestimation.

Here, the authors develop a method of simultaneous optimisation of precoder and equaliser for the multi-user multiple-input multiple-output (MIMO) system by minimising outage probability. In order to do that, the authors first characterise the signal-to-interference-plus-noise ratio of downlink multi-user MIMO system in the presence of both multi-user interference and self-interference. The closed-form expression for the outage probability is derived in terms of the eigenvalues of an indefinite weight matrix of a quadratic norm. Next, the authors develop an active-set algorithm-based precoder and equaliser by minimising the derived outage probability expression. This work investigates the effect of various system parameters such as the number of users, the number of multi-path channels, the number of transmitting and receiving antenna elements, and the additive noise variance on the outage probability and bit error rate. Simulation results validate the theoretical analysis for multiple system configurations. Lastly, the authors show that the designed precoder and equaliser improves the overall system performance.