Error rates for M-ary noncoherent FSK in impulsive reverberation noise

It is shown that reverberation noise for primary acoustic scattering in the ocean has an integral representation and that a canonical model for its analysis can be found. Exact values of error rates for M-ary noncoherent FSK for correlation receivers in such noise are given. Comparison with the well known Gaussian case is also made.     

Effect of correlated noise on error probability of binary frequency shift keying with limiter-discriminator-detector and narrowband filters

In investigations of frequency shift keying (FSK) with a limiter-discriminator-integrator (LDI) detector it was assumed that the noise at two consecutive sampling points is uncorrelated. Here we study the effect of correlated noise on error probability. We show that the error probability is reduced when the correlation is positive and increased when the correlation is negative. For optimal values of filter bandwidth the error probability remains unchanged.     

Error probability of binary phase shift keying in Nakagami-m fadingchannel with phase noise

The error performance of coherent detection of binary phase shift keying (BPSK) signals with noisy phase reference is analysed for a flat Nakagami-m fading channel and in the presence of additive white Gaussian noise (AWGN). By assuming Gaussian and Tikhonov probability density functions (PDFs) for the phase error, closed-form expressions for the average bit error rate (BER) are derived     

Threshold performance of M-ary noncoherent frequency-shift keying in non-Gaussian noise

An expression for the error probability of M-ary noncoherent frequency-shift keying (NCFSK) for locally optimum threshold detection in non-Gaussian noise, frequently encountered in practice, is derived, which demonstrates that a significant improvement in performance can be achieved when M is greater than two.     

Nonlinear continuous phase frequency shift keying

A novel signal-space coded CPM (continuous phase modulated) signaling technique, called nonlinear CPFSK (continuous phase frequency shift keying) signaling, which guarantees the maximum constraint length allowed by the number of states is introduced. Nonlinear CPFSK signals use a suitably selected state transition matrix during all signaling intervals. The selected state transition matrix is realized by changing the modulation index of the signals, hence the modulation index used during any interval depends on the transmitted symbol as well as on the state of the system. Binary nonlinear CPFSK signaling schemes are constructed and analyzed. Numerical results indicate that nonlinear CPFSK signals can achieve attractive minimum distances compared with other existing CPM signaling formats     

M-ary nonlinear continuous phase frequency shift keying

The authors present a new approach for designing a continuous phase frequency shift keying (CPFSK) system which is a nonlinear mapping of the M-ary symbols into the N-ary CPFSK. Using this approach they have designed an M-ary nonlinear CPFSK (NCPFSK) system of simple structure. The proposed M-ary NCPFSK system is a modification of the multi-h CPM (MHCPM) scheme. The proposed modulation gives improved performance over conventional modulation schemes     

Trellis codes for 4-ary continuous phase frequency shift keying

The approach of Morales-Moreno and Pasupathy (1988) is extended for the design of trellis codes for 4-ary continuous phase frequency shift keying (CPFSK) with modulation index h=1/2. The criterion for comparison of codes is the maximum free Euclidean distance for a given rate and the number of states of the signal space code. For the same number of states of the signal space code, these codes improve the free Euclidean distance by up to 1.25 dB over previously published results. Finally, the implementation of the combined coding and modulation system is discussed     

A digital signal processing type frequency locked loop for frequency shift keying demodulation

In this paper, we propose a digital signal processing type frequency locked loop (DSP-FLL) using a frequency difference detector (FDD). Since the DSP-FLL is controlled by the frequency, the pole of the voltage controlled oscillator vanishes in the baseband equivalent circuit. Therefore, the transfer function becomes first order and a ringing does not occur. Furthermore, it can be understood from the detection property of the FDD that a cycle slip does not occur and the DSP-FLL can pull in the frequency step input up to half of the sampling frequency.     

Multiple-symbol trellis-coded modulation applied to noncoherentcontinuous-phase frequency shift keying

This paper considers a maximum-likelihood (ML) noncoherent detection scheme for multiple full response continuous-phase frequency shift keying (CPFSK) waveforms and introduces a trellis-coded modulation (TCM) scheme for this noncoherent modulation. By utilizing a Gaussian approximation for Rician random variables, we express the pairwise error probability as a function of the equivalent normalized squared distance (ENSD). ENSD plays the same role as normalized squared Euclidean distance when evaluating error probability performance for coherent detection. We derive an analytical approximation on the bit-error probability by employing ENSD for both the coded system and the uncoded system. For the uncoded system we show that the bit-error probability of noncoherent detection approaches that of coherent symbol-by-symbol detection in the limit as the multiplicity of the symbol goes to infinity for large signal-to-noise ratio (SNR), We determine specific optimal trellis encoders for binary and 4-ary CPFSK with modulation index 1/2 and 1/4, respectively, by application of Ungerboeck's (1982) set partitioning approach     

Hybrid multi-h/multi-T continuous phase frequency shift keying

A class of hybrid multi-h/multi-T CPFSK signals is obtained by combining multi-h and multi-T signalling techniques. Hybrid signals are constructed by varying both the modulation index and the symbol duration simultaneously. Numerical results show that hybrid multi-h/multi-T signals perform significantly better than ordinary multi-h and multi-T signals     

扩展二元相移键控调制信号的多路传输

为有效利用信道资源,基于扩展二元相移键控(Extended Binary Phase Shift Keying,EBPSK)调制和解调的独特性,分析了多载波EBPSK调制的传输体制,推导出各路调制信号间参数约束关系,找出传输信号频谱变化规律,提出两种传输方案并设计相应的解调器,实现了多路EBPSK信号的并行传输;针对线谱分布规律修改调制波形,抑制了调制信号功率谱中的线谱杂散;取不同组调制参数进行仿真验证,结果表明两种方案的解调性能趋于一致且与载频间隔有关,载频趋近,系统实现复杂度提高,在相同误码率下解调所需信噪比额外支出约1～2 dB,但传输速率成倍提高,节省了频率资源,表明了这两种方法的可行性、有效性和利用信道资源的合理性.     

二进制差分随机过程键控的结构与性能分析

提出了一种二进制差分随机过程键控的调制解调结构,推导出了在高斯信道和准静态衰落信道下的误比特率理论计算公式,并对系统进行了误比特率和二阶循环谱检测的仿真。仿真结果表明,提出的差分随机过程键控,在高斯信道下大约在?2 dB、在准静态瑞利衰落信道下大约在25 dB的信噪比下具有10?4数量级的误比特率。同时,所提出的差分随机过程键控调制方法,其广义二阶循环谱的不可检测性,使其具有很好的物理层隐蔽性。     

2.4 GHz direct-digital binary phase shift keying modulator using MEMS switch

A novel MEMS-based binary phase shift keying direct-digital modulator operating at a carrier frequency of 2.4 GHz is presented. The circuit is composed of a rat-race coupler and a single-pole double-throw MEMS switch controlled by a digital baseband signal. The coupler divides the input waveform into two signals that are 180/spl deg/ out of phase and the MEMS switch is used to select between these two signals. This circuit has been experimentally verified and results are reported.     

α稳定分布噪声下数字频移键控信号的分数低阶循环谱分析

针对α稳定分布噪声环境下数字通信信号的二阶与高阶循环统计特征显著退化问题,结合分数低阶矩和共变理论对二进制频移键控（Frequency Shift Keying,FSK）信号的分数低阶循环谱公式进行了理论推导,并对2FSK信号在不同混合信噪比、分数阶因子和特征指数条件下的分数低阶循环谱进行了详细的仿真分析.理论和仿真结果表明:2FSK信号分数低阶与二阶的循环谱结构相同,其谱峰对应的循环频率相同,谱峰的幅度值不同,取决于循环谱的阶因子.相对于在低混合信噪比下失效的二阶循环谱,分数低阶循环谱对α稳定分布噪声具有更强的抗干扰性和适用性.     

Asymptotic error-rate behavior for noncoherent on-off keying in thepresence of fading

This article investigates the asymptotic error-rate behavior for the noncoherent on-off keying (OOK) signaling scheme in different fading environments and at both extremes of the signal-to-noise ratio (SNR). A transcendental equation to compute the optimum threshold level of noncoherent OOK operating over a Rician fading channel is derived. The optimum threshold level and its corresponding ratio of the mark and space error probabilities in additive white Gaussian noise (AWGN). Rayleigh, and Rician channels are tabulated as a function of the SNR. Geist (see ibid., vol.42, p.225, 1994) has shown that mark and space errors contribute equally to the average error probability in an AWGN channel when the SNR is large with optimum threshold setting. We show that mark errors predominate when the SNR is small and/or in fading channels     

最小移频键控信号的检测和误码性能分析

首先介绍了MSK信号差分检测原理。其次,分析了存在相关高斯噪声和信道有瑞利衰落时MSK的抗噪声性能。结果表明,在高斯噪声时的差分MSK的误码率与DPSK相同;而当信道存在瑞利衰落时将严重影响系统的抗噪声性能。所得结论能为系统的设计提供重要依据。     

Optical frequency domain differential phase shift keying infemtosecond-pulse spectral modulation systems

We propose a novel scheme of differential phase shift keying (DPSK) in the optical frequency domain. We take advantage of the intrinsic coherence among spectral elements derived by spectrum slicing a femtosecond optical pulse, introducing differential phase modulation between adjacent spectral elements with a femtosecond-pulse shaper. Detection of the differential phase is achieved by a Mach-Zehnder (MZ) or Sagnac interferometric receiver without requirement of any external phase reference     

A novel method of high speed frequency shift keying modulation in mm waves

To place a high speed switching diode in the cavity of the mm wave scillator has the behavior equivalent to an inductive post. The on-and-off switching of the diode will give rise to the change of inductance, hence the change of parameters of the cavity, and the osaillating frequency. In this article, the basic principle and the measured result are given. It is found that this is an efficient method in high speed frequency shift keying (FSK) modulation for a mm wave transmitter in communication.     

Diversity combining for coherent and differential M-PSK in fading and class-A impulsive noise

In this paper, optimum and suboptimum diversity combining schemes for coherent and differential M-ary phase-shift keying (M-PSK) transmission impaired by general Ricean fading and impulsive Class-A noise are derived and analyzed. The proposed suboptimum coherent combining (SCC) and suboptimum noncoherent combining (SNC) schemes yield similar performance as the corresponding optimum combining schemes but require a lower computational complexity. In addition, the novel SCC and SNC strategies achieve large performance gains over conventional maximum ratio combining (MRC) and equal gain combining (EGC), respectively. For MRC and EGC, respectively, we also provide a performance analysis for coherent and differential M-PSK transmissions over general Ricean fading channels with Class-A noise. Furthermore, tight performance upper bounds for the proposed optimum and suboptimum combining schemes are derived.     

Direct detection optical communication receiver performance for intensity subcarrier frequency shift keying (Corresp.)

The performance of recently developed doubly stochastic Poisson process filtering and detection procedures, as experimentally measured for a direct detection laser intensity modulated subcarrier frequency shift keying communication format, is reported.