SOI CMOS Implementation of a Multirate PSK Demodulator for Space Communications

A low-power phase-shift keying demodulator integrated circuit (IC) has been implemented using silicon-on-insulator CMOS technology for deep space and satellite applications. The demodulator employs double differential detection to increase its robustness to the Doppler shift caused by the movement of the space vehicle and sampling technique with 1-bit analog-to-digital converter (ADC) at the front to reduce the complexity and power dissipation. In particular, digital decimation is used after sampling to achieve a low power implementation of multirate transmission. Operating at ultra-high-frequency (435 MHz), the receiver system supports a wide range of data rates (0.1-100 Kbps). From test results, the power consumption of the demodulator circuit including the 1-bit ADC is below 1 mW for data rates up to 100 Kbps     

A low-power all-digital FSK receiver for space applications

A frequency-shift keying (FSK) receiver has been designed for deep space applications which exhibits potential for ultra low power performance. The receiver is based on a novel, almost all-digital architecture. It supports a wide range of data rates and is very robust against large and fast frequency offsets due to Doppler. The architecture utilizes subsampling and 1-bit data processing together with a discrete Fourier transform-based detection scheme to enable power consumption dramatically lower than implementations reported in the literature. Novel and power-efficient algorithms are derived for frequency and timing tracking. Most of the power saving techniques are applicable to a variety of applications, but some are achieved by taking advantage of the asymmetric power constraints for the receiver and the transmitter as well as the absence of adjacent channel interferers. The worst-case bit-error rate (BER) performance of the receiver is just 2.5 dB below that of the optimal uncoded noncoherent FSK receiver at a BER of 10^-6 and better for lower BERs     

Transmission Performance Comparison of Direction Detection‐Based 100‐Gb/s Modulation Formats for Metro Area Optical Networks

Transmission performances of direct detection‐based 100‐Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal‐to‐noise ratio sensitivity, chromatic dispersion, cross‐channel nonlinearity, and transmission distance on the performance of differential 8‐ary phase‐shift keying (D8PSK), differential phase‐shift keying plus three‐level amplitude‐shift keying (DPSK+3ASK), and dual‐carrier differential quaternary phase‐shift keying (DC‐DQPSK) are evaluated. The performance of coherent dual‐polarization quadrature phase‐shift keying (DP‐QPSK) with block phase estimation and coherent DP‐QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100‐Gb/s signal over several hundred kilometers of a single‐mode fiber link. The results also show that DC‐DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC‐DQPSK is comparable to that of coherent DP‐QPSK with digital differential detection. The maximum transmission distance of DC‐DQPSK is over 1,000 km, which is enough distance for metro applications.     

Sample size required in error-rate measurement on fading channels

This paper presents analytical and numerical results on the sample size required to achieve a specified root mean square (RMS) error in estimating the error rate for flat fading channels having complex Gaussian statistics. The analysis shows that for the large sample sizes normally used in estimating error rates, k, the required sample size normalized to the required sample size for independent symbol fading, can be expressed in the form k=1+dβ where d is the symbol rate normalized to the Doppler spread of the channel. For a given modem, β is a function of the error probability and the order of diversity. It is shown that if the Doppler spread measure used is proportional to the RMS Doppler spread, P will be relatively insensitive to the shape of the Doppler power spectrum. Numerical results are presented for Lth order diversity reception of binary phase shift keying (PSK), differential PSK, and frequency shift keying (FSK) signals and for five different Doppler power spectra. Ideal maximal ratio combining is assumed for the PSK modem, and square law combining is assumed for the DPSK and FSK modems     

Noncoherent maximum-likelihood block detection of orthogonalNFSK-LDPSK signals

This paper investigates the noncoherent block detection of orthogonal N frequency-shift keying (FSK)-L differential phase shift keying (DPSK) signals transmitted over the additive white Gaussian noise channel, based on the principle of maximum-likelihood (ML) sequence estimation. By virtue of a union bound argument, asymptotic upper bounds for the bit error probability of the developed ML block receiver are derived and verified by simulation. It is analytically shown that the noncoherent NFSK-LDPSK ML block receiver performs comparably with the ideal coherent NFSK-L phase shift keying (PSK) receiver for L = 2 and 4, as the observation block length is large enough. Furthermore, substantial performance improvement can be achieved by the ML block detection of the NFSK-LDPSK signal with L > 2 by increasing the observation block length     

大规模MIMO系统多用户PSK调制方案的优化

针对超可靠低时延通信短包传输特征,在大规模多输入多输出( Multiple-Input Multiple-Output,MIMO)上行链路系统中,利用较低导频开销来设计相移键控( Phase Shift Keying,PSK)调制方案,并对该方案进行优化兼顾无线链路传输的可靠性.首先,在接收端构建基于最小欧式距离的非相...     

A compensability RF CMOS mixed-signal interface for implantable system

The implantable microsystem requires the hybrid circuit technology for a brain-machine interface. The paper described a compensability mixed-signal implantable receiver including an analog front-end and a digital processing circuit. The analog circuit consists of mainly an amplifier, an amplitude shift keying (ASK) demodulator, a clock extraction and a power recovery. In this paper, the amplifier and the ASK demodulator are described and provided without the capacitor and the resistor, fully integrated low-power circuit. The processing circuit is designed with the digital technology, so that implementing the correct synchronous signal. The carrier frequency of the circuit is applied in the 10 MHz range; the data rates up to 1 M bit/s are supported, suitable for complex implants such as the brain neural stimulating and so on. The compensability low-power and the high-performance implantable interface using a CMOS technology has been designed, fabricated and verified. All of circuits were implemented in a standard 0.18-μm CMOS process.     

Dynamic stimulated Brillouin scattering analysis

We present a new simple analysis-including the effect of spontaneous emission-of the (dynamic) influence of stimulated Brillouin scattering (SBS) on the detected receiver eye diagram. It applies in principle for general types of modulation formats such as the digital formats of amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK). The analysis is formulated for a determination of the signal power depiction and intersymbol interference (ISI) caused by the combined effect of fiber dispersion, fiber attenuation and nonlinear fiber effects such as the effect of self-phase modulation (SPM) and SBS. The analysis allows a quantification of the dithering influence on the SBS threshold. Representative numerical examples are presented for two single-channel ON-OFF modulated 10-Gh/s systems utilizing Franz-Keldysh and Mach-Zehnder-type modulators     

Comparison of 112-Gb/s PM-RZ-DQPSK and PM-RZ-D8PSK in Terms of OSNR Requirement and Transmission Impairments

We have, for the first time, experimentally investigated 112-Gb/s polarization-multiplexed return-to-zero differential 8-ary phase-shift keying (PM-RZ-D8PSK) with differential detection in terms of optical signal-to-noise ratio requirement, group velocity dispersion (GVD), and differential group delay (DGD) tolerances, together with a direct comparison with PM-RZ differential quadrature phase-shift keying at equivalent bit rate. The results indicate higher tolerances with respect to GVD and DGD but lower receiver sensitivity in the case of PM-RZ-D8PSK.      

Modulation and coding for mobile radio communications: channelswith correlated Rice fading and Doppler frequency shift

We discuss the relative performance of coherent phase-shift keying (PSK), differential PSK (DPSK), and double differential PSK (DDPSK) modulation schemes over a mobile radio channel in which transmission is affected by additive noise, a constant carrier phase offset, a constant Doppler frequency shift, and correlated Rice fading. We first compare the performance of these schemes to assess the amount of degradation caused on each one of them by fading. Among our findings, we observe that DDPSK turns out to be less sensitive to the effects of correlated fading than the other two schemes and that in these conditions interleaving may not be beneficial. We then consider the introduction of trellis-coded modulation (TCM). The system we advocate as offering the best tradeoff between performance and complexity with the channel model assumed here includes double-differential encoding, differential detection, an open-loop Doppler phase tracking circuit, and differential decoding in addition to a simple TCM scheme     

fso中一种光载波外差dpsk系统的设计

介绍了自由空间光通信中的相干通信系统,通过对相干光通信中振幅键控(ASK),频移键控(FSK),相移键控(PSK),差分相移键控(DPSK)四种光载波相干调制方式性能的分析和比较,仿真结果得出PSK调制误码性能更好,提出了一种光载波外差差分相移键控(DPSK)系统.     

Phase diversity receivers for homodyne detection of optical DQPSK signals

Phase diversity (PD) receivers are an elegant option to handle the phase noise at homodyne detection and are especially interesting when used as wideband tunable wavelength-division multiplexing receivers. In the late 1980s and early 1990s, they were proposed and investigated for binary modulation formats (amplitude-shift keying, differential phase-shift keying, and frequency-shift keying). In this paper, a homodyne PD receiver for differential quadrature phase shift keying (DQPSK) modulation is analyzed, which provides a promising alternative to presently investigated DQPSK-direct-detection receivers and homodyne receivers with digital phase estimation.     

Analysis and design of a frequency-hopped spread-spectrumtransceiver for wireless personal communications

Personal communications services (PCS) require low-power radio technologies. One such transceiver architecture employing frequency-hopped spread-spectrum techniques is presented. System features such as antenna diversity with equal-gain combining and sequential hop combining are incorporated into the transceiver design to achieve robust wireless digital data transmission over fading channels. A direct-conversion architecture from radio frequency (RF) to baseband reduces the overall power consumption by eliminating intermediate frequency (IF) components. High-rate frequency hopping with frequency-shift keying (FSK) modulation is implemented using a direct digital frequency synthesis technique. A multiplierless correlation FSK detector, suitable for direct-conversion receivers, has been designed for quadrature noncoherent detection. Robust acquisition algorithms based on energy detection and pattern matching and tracking architectures using digital phase-locked loops are also described for system synchronization. The proposed transceiver is well-suited for low-power PCS applications and other portable wireless communications     

调制解调非理想特性联合补偿数字预失真方法

针对调制解调非理想特性影响数字预失真效果,导致邻信道功率比性能较差的问题,提出了一种调制端和解调端联合补偿的数字预失真方法。首先,建立了正交调制器、解调器的基带等效模型;然后,基于多项式预失真,利用正交调制器与解调器的特点,结合递归最小二乘法,推导出了联合补偿数字预失真原理,避免了仅通过调制端补偿,或者调制端、解调端分别补偿只能使数字预失真算法收敛到局部最优解的现象出现;最后,以甚高频航空通信常用的差分八相移键控（Differential 8 Phase Shift Keying,D8PSK）调制方式为例进行了仿真和实现验证,邻信道功率比相对无预失真可以改善28 dBc,相对现有联合补偿数字预失真可以改善16 dBc。     

Error floors in the satellite and land mobile channels

In a satellite mobile channel (SMC) and land mobile channel (LMC) because of fading and nonlinear power amplifiers, constant envelope modulation and noncoherent detection methods may outperform other schemes. It is shown how to compute the error floor for four noncoherent digital communication systems in satellite and land mobile channels. Differential phase shift keying (DPSK) with differential phase detection (DPD) or frequency shift keying (FSK) with DPD, limiter discriminator integrator detection. (LDID), or limiter discriminator detection (LDD) are studied. The error floor is the residual error probability when SNR is infinity, i.e. the error probability in the system is limited by the error floor. The error floor is computed as a function of Doppler frequency, modulation index, and ratio of powers in the specular and diffuse signal components for DPSK-DPD, FSK-DPD, FSK-LDID and FSD-LDD systems     

Noncoherent ultra-wideband systems

The need for low-complexity devices with low-power consumption motivates the application of suboptimal noncoherent ultra-wideband (UWB) receivers. This article provides an overview of the state of the art of recent research activities in this field. It introduces energy detection and autocorrelation receiver front ends with a focus on architectures that perform the initial signal processing tasks in the analog domain, such that the receiver does not need to sample the UWB received signals at Nyquist rate. Common signaling and multiple access schemes are reviewed for both front ends. An elaborate section illustrates various performance tradeoffs to highlight preferred system choices. Practical issues are discussed, including, for low-data-rate schemes, the allowed power allocation per pulse according to the regulator?s ruling and the estimated power consumption of a receiver chip. A large part is devoted to signal processing steps needed in a digital receiver. It starts with synchronization and time-of-arrival estimation schemes, introduces studies about the narrowband interference problem, and describes solutions for high-data-rate and multiple access communications. Drastic advantages concerning complexity and robustness justify the application of noncoherent UWB systems, particularly for low-data-rate systems.     

无线信道中M元（D）PSK信号的多普勒相移估值与校正

本文提出了一种新的无线信道中Ｍ元（Ｄ）ＰＳＫ信号的多普勒相移估值与校正方案，分析了性能，展示了该估值器和校正器的分析和计算机模拟结果，并分析了校正后的误码特性。理论分析和模拟结果表明，该方法是一种有效的多普勒相移估值和校正方法。     

An improvement effect by a hard-limiter on differential detection performance of PSK in frequency-selective fading

Differential detection of PSK after an IF hard-limiter is described. This detection scheme is well known for the reason that the receiver structure is greatly simplified with saturated amplifiers and a digital-type differential detector. In addition, it can give the improved effect of reducing eye pattern timing fluctuation which is found to be a cause of excessive errors in a frequency-selective fading channel. Error rates were measured for binary and quadrature phase-shift keying. The results show great improvement over the detection scheme employing linear amplifiers and an analog differential detector.     

A 3-V, 0.35-/spl mu/m CMOS Bluetooth receiver IC

A fully integrated CMOS low-IF Bluetooth receiver is presented. The receiver consists of a radio frequency (RF) front end, a phase-locked loop (PLL), an active complex filter, a Gaussian frequency shift keying (GFSK) demodulator, and a frequency offset cancellation circuit. The highlights of the receiver include a low-power active complex filter with a nonconventional tuning scheme and a high-performance mixed-mode GFSK demodulator. The chip was fabricated on a 6.25-mm/sup 2/ die using TSMC 0.35-/spl mu/m standard CMOS process. -82 dBm sensitivity at 1e-3 bit error rate, -10 dBm IIP3, and 15 dB noise figure were achieved in the measurements. The receiver active current is about 65 mA from a 3-V power supply.     

A 60-GHz 38-pJ/bit 3.5-Gb/s 90-nm CMOS OOK Digital Radio

A 60-GHz fully integrated bits-in bits-out on–off keying (OOK) digital radio has been designed in a standard 90-nm CMOS process technology. The transmitter provides 2 dBm of output power at a 3.5-Gb/s data rate while consuming 156 mW of dc power, including the on-chip 60-GHz frequency synthesizer. A pulse-shaping filter has been integrated to support high data rates while maintaining spectral efficiency. The receiver performs direct-conversion noncoherent demodulation at data rates up to 3.5 Gb/s while consuming 108 mW of dc power, for a total average transceiver energy consumption of 38 pJ/bit in time division duplex operation. To the best of the authors' knowledge, this is the lowest energy per bit reported to date in the 60-GHz band for fully integrated single-chip CMOS OOK radios.