Intersymbol Interference (ISI) Suppression Technique for Optical Binary and Multilevel Signal Generation

An intersymbol interference (ISI)-suppressed optical multilevel modulation technique that is applicable to a wide range of binary and multilevel signaling is proposed. It employs binary phase-shift keying modulations that are generated by Mach-Zehnder intensity modulators as basic building blocks, and complex multilevel modulations are synthesized using interferometric addition and tandem modulations. Its feasibility and ISI suppression effect are verified in various binary and multilevel signal synthesis schemes using numerical simulations. Furthermore, the generation of ISI-suppressed zero-chirp binary and quaternary amplitude-shift keying modulations is experimentally demonstrated. Finally, its applicability to complex optical multilevel signaling is shown in the generation of a 40-Gb/s 16-level amplitude- and phase-shift keying signal, which results in 3-dB sensitivity improvement compared with the one using a conventional four-level electrical driving signal.     

New Simple Closed-Form BER Expressions for MRC Diversity BPSK in Correlated Rayleigh Fading and CCI

Exact closed-form expressions are derived for the bit error rate of binary phase shift keying in Rayleigh fading channels with maximal ratio combining diversity in the presence of cochannel interference and additive white Gaussian noise. The desired signal and the interferer signals are subject to correlated Rayleigh fading and binary phase shift keying modulation is used by all users.     

Performance comparison of different MSK implementations

Minimum-shift keying (MSK) can be implemented as binary continuous-phase frequency-shift keying (CPFSK) or a special form of offset quadrature phase-shift keying (OQPSK). A modified CPFSK implementation is proposed for AWGN channels since the conventional CPFSK implementation suffers from error propagation     

基于BPSK和QPSK频带传输的PCMA研究

PCMA理论上可将现有的卫星通信容量提高一倍.文中对Simulink仿真模块参数进行设定,搭建键控法的二进制相移键控（binary phase shift keying,BPSK）模型和调相法的正交相移键控（quadrature phase shift keying,QPSK）模型,以及基于BPSK和QPSK的频带传输的PCMA通信系统仿真,分析了自我信号复制模块中的时延估计算法.仿真结果验证了理论的一致性.     

Nonlinear signal–noise interactions in dispersion-managed links with various modulation formats

Purpose of this paper is to highlight the principles of the nonlinear signal–noise interaction (NSNI) in dispersion-managed long-haul optical links and provide a quantitative understanding of the system parameters for which NSNI sets the nonlinear performance of the most popular intensity and phase modulation formats, namely on–off keying, differential binary and quadrature phase-shift keying and coherent quadrature phase-shift keying.     

The Distribution of Error Probability for Rayleigh Fading and Gaussian Noise

The distribution function of the probability of error in the presence of Rayleigh fading and Gaussian noise is determined for the basic binary modulation schemes of coherent frequencyshift keying (CFSK), noncoherent frequency-shift keying (NCFSK), differential phase-shift keying (DPSK), and coherent phase-shift keying (CPSK). General expressions for the distribution function of error probability are also derived when linear maximal-ratio diversity combining is employed. Results are given for various values of average error probability and various orders of diversity.     

Mutual interferences in a binary FH-FSK spread spectrum system for mobile radio

A binary frequency-hopped frequency shift keying (FHFSK) spread spectrum system for mobile radio communication as well as an address assignment scheme for such a system and an evaluation of error probabilities due to mutual interferences in binary FH-FSK in function of the number of simultaneous users are presented. In the absence of any form of synchronization between sequences, the system's performance is not as good as frequency-hopped differential phase shift keying (FH-DPSK) for any decoding scheme; decoding with intermediate decisions on interval pairs (i, i + L/2) in a sequence of length L gives approximately the same performance as when using only the combiner circuit and maximum likelihood decoding. With synchronization between sequences at the chip level, however, the results show binary FH-FSK performance comparable to that of frequency-hopped multilevel frequency shift keying (FH-MFSK) and thus, substantially better than that of FH-DPSK.     

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.     

Detection of decision error caused by the quantum noise in anoptical signal system

In this paper, a signal transmission and decision system in which an event of occurrence of decision error caused by the quantum noise can be detected is presented. The system is, in principle, constituted on the basis of a binary polarization-shift keying (PolSK) signal. Using retransmission technology for the error detection system, the decision error probability can be suppressed to 0. The binary PolSK system uses two polarization channels, and then the system has redundancy on channel efficiency. A more efficient signal system which uses only one polarization channel and is based on the binary phase-shift keying (PSK) signal is presented     

Performance analysis of dual-hop fixed-gain AF relaying systems with OSTBC over Nakagami-m fading channels

In this paper, we present outage probability and symbol error rate (SER) performance analyses of a dual-hop transmission using fixed-gain amplify-and-forward relaying in flat Nakagami-m fading channels. The system under consideration is equipped with multiple antennas at source and destination adopting orthogonal space-time block coding to provide transmit diversity and maximum ratio combining to provide receive diversity, respectively. For integer and half-integer m values, closed forms of exact outage probability and moment generating function (MGF) expressions are derived through cumulative distribution function (CDF) of the overall system signal-to-noise ratio. Closed-form exact SER expressions based on the overall CDF are obtained for binary phase shift keying, binary frequency shift keying and M-ary pulse amplitude modulation. Exact SER expressions based on the MGF method are also obtained for binary differential phase shift keying, M-ary phase shift keying and M-ary quadrature amplitude modulation. Moreover, the asymptotic diversity order analysis is performed through derivations of asymptotic outage probability and SER. Theoretical analyses are validated by Monte Carlo simulations showing perfect match between each other.     

Precise BER analysis of dual-channel reception of QPSK in Nakagami fading and cochannel interference

A precise bit error rate analysis is performed for bandwidth-efficient dual-channel quadrature phase shift keying in Nakagami fading with Nakagami-faded asynchronous interfering signals. In contrast to previous works, the analysis accounts for the dependencies between the quadrature carriers owing to nonRayleigh fading and cochannel interference. The impact of the interfering users' fading severities on the desired user bit error rate is investigated. A comparison of the bit error performance for binary phase shift keying and quadrature phase shift keying is given.     

Optical power requirements for detecting OOK and FSK signalscorrupted by phase noise

The decision of on-off keying (OOK) and frequency-shift keying (FSK) is considered for coherent lightwave communications in which the optical pulses are corrupted by the phase noise associated with nonzero laser linewidths. Heterodyne lightwave detection is assumed, followed by intermediate frequency filtering, envelope detection, and postdetection low-pass filtering. Using analytical results published previously, theoretical minimum values of the required average power are obtained in photons/bit, for achieving a bit error rate of 10^-9. Numerical results are given as functions of laser linewidth-to-bit-rate ratio for OOK, binary FSK (or 2-FSK), and 8-FSK. It is shown that heterodyne detection for lightwave signals of this kind can be made highly robust to phase noise, in contrast to the case of binary phase-shift keying     

A New Soft‐Fusion Approach for Multiple‐Receiver Wireless Communication Systems

In this paper, a new soft‐fusion approach for multiple‐receiver wireless communication systems is proposed. In the proposed approach, each individual receiver provides the central receiver with a confidence level rather than a binary decision. The confidence levels associated with the local receiver are modeled by means of soft‐membership functions. The proposed approach can be applied to wireless digital communication systems, such as amplitude shift keying, frequency shift keying, phase shift keying, multi‐carrier code division multiple access, and multiple inputs multiple outputs sensor networks. The performance of the proposed approach is evaluated and compared to the performance of the optimal diversity, majority voting, optimal partial decision, and selection diversity in case of binary noncoherent frequency shift keying on a Rayleigh faded additive white Gaussian noise channel. It is shown that the proposed approach achieves considerable performance improvement over optimal partial decision, majority voting, and selection diversity. It is also shown that the proposed approach achieves a performance comparable to the optimal diversity scheme.     

Multilevel logic operations

The multilevel logic operations (MLOs) that are extended from the conventional binary logic operations are defined. MLOs are useful for designing digital circuits based on binary logic. Application examples of multiple BPSK (binary phase shift keying) circuits are given to show the design efficiency of these MLOs     

All-Optical NRZ-OOK to BPSK Format Conversion in an SOA-Based Nonlinear Polarization Switch

All-optical format conversion from nonreturn-to-zero on-off keying to binary phase-shift keying is demonstrated in a semiconductor optical amplifier-based nonlinear polarization switch. This conversion is realized by cross-phase modulation effect for phase encoding and nonlinear polarization rotation effect for amplitude equalization. In the experiment, error-free operation at 10 Gb/s is achieved with a receiver sensitivity penalty of 1.3 dB after single-ended detection.     

Exact average symbol error probability of optimum combining with arbitrary interference power

A new expression is derived for the exact average symbol error probability for optimum combining with M-ary phase-shift keying. The expression adds to the significant body of work in this field by handling interferers with arbitrary power levels. The expression involves a single integral with finite limits and finite integrand. A closed-form expression is also derived for the average symbol error probability for binary phase-shift keying.     

Noncoherent block demodulation of MSK with inherent and enhancedencoding

It is shown that there is a close relation between known noncoherent minimum shift keying (MSK) demodulation structures, such as envelope and differential receivers, and schemes derived from the noncoherent maximum-likelihood block estimation (N-MLBE) principle. When the observation interval is increased, the performance of MSK with N-MLBE tends to that of binary coherently detected orthogonal binary frequency shift keying. A new demodulation strategy, reduced block noncoherent estimation (RBNE), is introduced and shown to improve the performance of noncoherent MSK, beyond that of coherently detected orthogonal FSK. When RBNE is used with MSK and the observation interval is increased, the performance approaches that of antipodal signaling. The key feature of all these structures is multisymbol noncoherent processing with exploitation of the MSK inherent coding properties induced by its phase continuity. The use of binary block codes for MSK with N-MLBE is considered. It is shown that simple binary block codes with low bandwidth expansion that exploit the inherent MSK memory can give significant gains     

双发射天线选择正交空时码分集系统性能分析

针对任意Nakagami衰落信道,分析了多输入多输出(MIMO)系统中采用双发射天线选择正交空时码的平均误码率(ASER)性能。利用矩生成函数方法,推导出采用相干检测的二进制相移键控/二进制频移键控(BPSK/BFSK)、多进制相移键控(MPSK)和多进制正交幅度调制(MQAM)的精确ASER闭合解析式,对不同条件下的系统性能做了数值仿真,验证了分析结果的正确性。     

BER performance of dual predetection EGC in correlative Nakagami-m fading

In this letter, an approach to the evaluation of the error performance in dual predetection equal-gain combining (EGC) systems over correlated Nakagami-m fading channels is presented. Deriving an infinite series representation for the characteristic function of the sum of two correlated Nakagami-m variables, a closed-form formula is extracted for binary phase-shift keying and coherent binary frequency-shift keying, while several other modulation schemes are studied, capitalizing on a Parsevals's theorem-based approach, previously published. Numerical results and simulations are also presented to illustrate the proposed mathematical analysis and to point out the effect of the input signal-to-noise ratio unbalancing, the fading severity, and the fading correlation on the system's error performance.     

Phase jitter in MPSK carrier tracking loops: analytical, simulationand laboratory results

A performance characteristic of M-ary phase shift keying (MPSK) receivers is the variance of the phase error between the received and recovered signal carriers. For binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) loops utilizing integrate and dump filters and operating in the linear region, closed-form solutions for this variance exist (Hinedi and Lindsey 1989; and Yuen 1983). In this paper the variance is found by numerical methods for M>4. For verification and to investigate operation in the nonlinear region, computer simulation and hardware modeling were used (Kopp 1994)