Bit Error Rate Estimation Research Articles

Effect of controllable parameter synchronization on the ensemble average bit error rate of space-to-ground downlink chaos laser communication system.

Chaotic modulation is a scheme used to enhance the information security through the configuration parameter synchronization. When chaotic modulation is adopted in the space-to-ground laser communication system, the traditional bit error rate (BER) calculation model for fiber-based chaos communication system is no longer available to depict the long-term communication performance. To solve this problem, we established a new ensemble average BER calculation model under the effects of intensity scintillation and pointing error. Based on this model, we conduct a simulation to research such a system, and our numerical results indicate that space-to-ground chaos laser communication system has a great anti-interference against these two effects when the detector mismatch approaches zero. Our results display the advantages of chaotic modulation and also reflect the characteristics of space-to-ground chaos laser communication system.

Sparse Channel Estimation of Underwater TDS-OFDM System Using Look-Ahead Backtracking Orthogonal Matching Pursuit

Time division synchronization orthogonal frequency division multiplexing (TDS-OFDM) has been attractive due to its fast synchronization and efficient spectral efficiency over conventional cyclic prefix orthogonal frequency division multiplexing (OFDM) and zero padding OFDM. However, inter-block interference (IBI) affects its performance because of delay over multipath channels. To evade IBI, dual pseudo-random noise (DPN) sequences have been introduced that causes to reduce spectral and energy efficiency. But, DPN is unprepared for underwater acoustic (UWA) communication because of battery-based nature and limited bandwidth. To overcome these issues, this paper exploits compressive sensing theory algorithm for obtaining the time-varying channel state information by utilizing sparse property of UWA channels. In this paper, the IBI free region is utilized to estimate accurate UWA channel impulse response and mitigate its interference. Look-ahead backtracking orthogonal matching pursuit-based sparse channel estimation technique is proposed for underwater TDS-OFDM in a real sparse time-varying multipath channel (channel taps are randomly distributed). Furthermore, Doppler-shift of UWA channel is estimated and compensated by PN sequence in time domain. The performance of the proposed technique is evaluated and demonstrated through numerical computation of bit error rate (BER) and mean square error (MSE) using Monte Carlo iterations. Simulation analysis confirms the superiority of the proposed scheme not only in terms of BER and MSE over the conventional ones but also achieve high energy and spectral efficiency.

Unified Performance Analysis of Transmit Antenna Selection With OSTBC and Imperfect CSI Over Nakagami- m Fading Channels

A unified error analysis of multi-antenna systems with orthogonal space-time block coding (OSTBC) using transmit antenna selection (TAS) over Nakagami- $m$ channels in the presence of feedback delay and channel estimation error is presented, where the number of transmit antennas is arbitrarily selected. For imperfect channel state information (CSI), the Nakagami- $m$ channel is modeled as the sum of Nakagami- $\hat{m}$ channel and independent Gaussian channel error. By this model, accurate and closed-form approximate bit error rate (BER) expressions of TAS-OSTBC for M-ary quadrature amplitude modulation and M-ary phase-shift keying are derived by using the moment generating function of received SNR. With the approximate BER formula, the number of antennas to be selected for transmission can be adapted by minimizing the BER of the system with imperfect CSI. The diversity and coding gains of TAS-OSTBC with $K$ receive antennas and $M$ antennas selected from $N$ transmit antennas for transmission are analyzed at high SNR. For noninteger $mK$ , the upper and lower bounds of the diversity gain for different CSI and estimation error scenarios are derived. But for integer $mK$ , the results indicate that the upper and lower bounds are equal achieving the full diversity order of $mKN$ for perfect CSI, zero diversity order and partial diversity order of $mMK$ for estimation error variance being fixed and being a decreasing function of average SNR, respectively. The coding gain is affected by $M$ , $N$ , $K$ , Nakagami parameter $m$ , code rate, modulation, and channel correlation coefficients. Simulation results verify the validity of the theoretical analysis and effectiveness of the adaptive antenna selection scheme.

Error Performance Analysis of Diffusive Molecular Communication Systems With On-Off Keying Modulation

In this paper, we analyze the bit error rate (BER) of the diffusive molecular communication (DMC) systems employing on-off keying (OOK) modulation. We also analyze the BER of the OOK-modulated DMC systems with inter-symbol interference cancellation (ISIC). Our main motivation is to introduce alternative tools for analyzing and efficiently computing the BER of the DMC systems without or with ISIC. Specifically, for the OOK-modulated DMC systems without ISIC, we first derive an exact BER expression based on the Poisson modeling of DMC systems. Then, the Gaussianand Gammaapproximation approaches are introduced to approximate the discrete Poisson distribution, and based on the approximation approaches, the corresponding BER expressions are derived. Furthermore, in order to reduce the computation complexity imposed by long inter-symbol interference, we propose the Monte-Carlo, simplified Poisson, simplified Gaussian, and the simplified Gamma approaches for BER computation. In the context of the OOK-modulated DMC systems with ISIC, we consider both the Poisson and Gaussian-approximation approaches for BER analysis. Again, exact and approximate BER expressions are derived under the Poisson, Gaussian-approximation, simplified Poisson, and simplified Gaussian approaches. Finally, the considered approaches are compared and validated by a range of performance results obtained from evaluation of the derived expressions or by simulations. Our studies show that the alternative approaches are in general effective for providing near-accurate BER estimation.

Effect of Correlation on BER Performance of the FSO-MISO System With Repetition Coding Over Gamma–Gamma Turbulence

In free space optical (FSO) communication systems, atmospheric turbulence is the major cause of bit error rate (BER) performance degradation. The error performance of the system can be significantly improved with the help of spatial diversity by employing multiple transmit or receive apertures. However, correlation of channels under turbulence in the case of small separation between transmit apertures can substantially reduce the benefits of spatial diversity. Still, a thorough analysis of the system performance in terms of diversity order and coding gain for the FSO multiple-input single-output (MISO) system under turbulence influenced correlated channels has not been studied when the repetition coding is used to achieve improved BER performance. In this paper, we provide unique results of the BER performance analysis of the considered correlated FSO-MISO system over Gamma–Gamma distributed turbulence channel. Using the joint moment generating function of received signal-to-noise ratio (SNR), a novel generalized approximate BER expression is derived, followed by convergence test of the power series based BER expression using the Cauchy's ratio test. Then, an asymptotic analysis at high SNR is performed to obtain a novel closed-form expression for BER of FSO-MISO system. We also derive expressions for coding gain, diversity gain, and coding gain loss due to correlation in channels. Although the effect of correlation in channels on the BER performance of the system is analyzed under different scenarios, while it is observed that it does not affect the diversity order; it significantly degrades the coding gain of the considered system.

An approach for realistic estimation of BER due to signal-component crosstalk in a WDM receiver

In this paper, an approach is proposed to estimate the Bit Error Rate (BER) in a Wavelength Division Multiplexing (WDM) receiver with component crosstalk considering all possible bit combinations in the interfering channels instead of the usual worst-case approach. In addition, probability density function (pdf) and bit error rate (BER) with finite interferers are studied using a new mathematical formulation based on Maclaurin series expansion of the N-th power of zero order Bessel Function. This analysis results in more realistic estimation of BER and optimum detection threshold for minimum BER than that obtained using worst-case study. The improvement in accuracy of estimation of BER with the present approach over the worst-case approximation approach is more for higher crosstalk level and large number of interfering channels.

On Die Bit Error Rate Estimator for NAND Flash Memory

In this brief, we propose a simple bit error rate (BER) estimator utilizing the parity check constraints of a low-density parity-check code-based error correction coding (ECC) scheme. The proposed estimator can be efficiently implemented on flash memory die with a very small area cost. We articulate applications in which flash memory controllers can take advantage of having the BER estimate before the ECC decoding scheme to significantly reduce programming errors and improve system performance in terms of latency and throughput.

On the BER performance of FSO links with multiple receivers and spatial jitter over gamma-gamma or exponential turbulence channels

Free-space optical (FSO) communication systems attract significant research and commercial interest due to their high performance characteristics along with their compact size, ease of deployment and the license-free spectrum that they use. Nevertheless, the time-varying characteristics of the atmosphere -which is the propagation path of the optical signal, and its variable composition of scatterers and absorbent matter, can cause significant distortions in the signal quality at the receiver. Thus, in this work we investigate the performance of an FSO link using receivers’ spatial diversity scheme and optimal combining reception. The performance assessment is carried out by means of the average bit error rate metric for some of the most widely used modulation formats on wireless optical links taking into account the atmospheric turbulence modeled either by the gamma-gamma or the negative exponential distribution model in conjunction with the pointing errors effect. More specifically, new closed-form mathematical expressions for the estimation of the average bit error rate are derived and could be easily used for the designing and implementation of the wireless optical links. The corresponding numerical results are presented along with the simulation ones and finally the outcomes’ conclusions are discussed.

Performance of Direct-Oversampling Correlator-Type Receivers in Chaos-Based DS-CDMA Systems Over Frequency Non-selective Fading Channels

In this paper, we present a study on the performance of direct-oversampling correlator-type receivers in chaos-based direct-sequence code division multiple access systems over frequency non-selective fading channels. At the input, the received signal is sampled at a sampling rate higher than the chip rate. This oversampling step is used to precisely determine the delayed-signal components from multipath fading channels, which can be combined together by a correlator for the sake of increasing the SNR at its output. The main advantage of using direct-oversampling correlator-type receivers is not only their low energy consumption due to their simple structure, but also their ability to exploit the non-selective fading characteristic of multipath channels to improve the overall system performance in scenarios with limited data speeds and low energy requirements, such as low-rate wireless personal area networks. Mathematical models in discrete-time domain for the conventional transmitting side with multiple access operation, the generalized non-selective Rayleigh fading channel, and the proposed receiver are provided and described. A rough theoretical bit-error-rate (BER) expression is first derived by means of Gaussian approximation. We then define the main component in the expression and build its probability mass function through numerical computation. The final BER estimation is carried out by integrating the rough expression over possible discrete values of the PFM. In order to validate our findings, PC simulation is performed and simulated performance is compared with the corresponding estimated one. Obtained results show that the system performance get better with the increment of the number of paths in the channel.

Non-Uniform Window Decoding Schedules for Spatially Coupled LDPC Codes

Spatially coupled low-density parity-check codes can be decoded using a graph-based message passing algorithm applied across the total length of the coupled graph. However, considering practical constraints on decoding latency and complexity, a sliding window decoding approach is normally preferred. In order to reduce decoding complexity compared with standard parallel decoding schedules, serial schedules can be applied within a decoding window. However, uniform serial schedules within a window do not provide the expected reduction in complexity. Hence, we propose non-uniform schedules (parallel and serial) based on measured improvements in the estimated bit error rate (BER). We show that these non-uniform schedules result in a significant reduction in complexity without any loss in performance. Furthermore, based on observations made using density evolution, we propose a non-uniform pragmatic decoding schedule (parallel and serial) that does not require any additional calculations (e.g., BER estimates) within the decoding process.

Model of bit error rate for laser communication based on superconducting nanowire single photon detector

The high-speed deep space communication is one of the key technologies for deep space exploration. Laser communication system equipped with sensitivity of single photon will improve existing deep space communication speed. However, laser communication at single photon level needs to consider not only the effect of transmission environment, but also the performance of used single photon detector and the photon number distribution. As a new single photon detector, superconducting nanowire single photon detector (SNSPD) outperforms the traditional semiconducting SPDs at near infrared wavelengths, and has high detection efficiency, low dark count rate, low timing jitter, high counting rate, etc. The SNSPD can be used for detecting single photons efficiently, rapidly and accurately. In this paper, we introduce the system detection efficiency and dark count rate of SNSPD based on the photoelectric detecting model without considering the effect of atmospheric turbulence, establish the mathematical model of bit error, and put forward the formula of system bit error rate. What should be emphasized is that the bit error rate is an important parameter for measuring the performance of laser communication system. Error is partly from background thermal radiation and circuit electromagnetic interference; in addition, error appears when photons reach the surface of device without being absorbed to successfully produce resistance area or photons are absorbed but there occurs no response. As a result, the calculation of bit error rate includes the whole process of photoelectric conversion. In order to analyze how to affect the size of system bit error rate, first we simulate two factors of the formula, i.e., light intensity and laser pulse repetition frequency. The results show that the light intensity has the greatest influence on error bit rate. With the light intensity increasing from 0.01 to 1000 photon/pulse, the error bit rate significantly decreases from 10-1 to 10-7 level. The influence of laser pulse repetition frequency is restricted by the light intensity, which declines with the increase of pulse repetition frequency. Then we measure the error bit rate experimentally, which validates the simulation model. However, when increasing light intensity or speed, experimental bit error rate is about 10-4 times higher than simulation result. The reason may be that the insufficiency of actual communication modulation extinction ratio of optical signal to the background noise through optical fiber increases the dark count rate. The above model and experimental results could be the foundation of high-speed deep space laser communication such as moon-earth and Mars-earth based on SNSPD.

An Approximate BER Analysis for Ambient Backscatter Communication Systems With Tag Selection

Ambient backscatter is a new technology that uses ambient signals to enable communication between battery-free tags (or sensors) and readers. Previous studies on ambient backscatter focused on scenarios with only one tag. In this paper, we investigate the ambient backscatter communication system with multiple tags and analyze the performance of tag selection. Specifically, we formulate a tag selection scheme and design the corresponding detection method. Our results indicate that obtaining the closed-form bit-error rate (BER) in such cases is challenging; hence, we provide a solution for deriving an approximate BER. The simulation results show that the approximated BER curves are in agreement with the exact curves.

Power imbalance induced BER performance loss under limited-feedback CoMP techniques

Coordinated multipoint (CoMP) technology utilizes simultaneous transmission/reception from/to different access points, and it is considered as an important feature to exploit and/or mitigate intercell interference in fourth-generation mobile networks. Yet, channel power imbalance at the receiver is experienced in CoMP systems due to, e.g., spatially distributed transmissions. Traditional co-located multi-antenna systems may also experience power imbalance among antenna branches due to inaccurate antenna calibration. This paper presents a bit error rate (BER) analysis and derives asymptotic and approximate BER expressions for some practical CoMP transmission techniques under channel power imbalance. Besides the analytical results, numerical analysis is made to thoroughly capture the performance impact of channel power imbalance on the performance gain of the CoMP methods. The results demonstrate that power imbalance considerably affects BER performance and applying long-term amplitude information with fast phase feedback has insignificant benefit to effectively compensate the detrimental effect of large channel power imbalance when base stations use a single antenna. In this case, exploiting both short-term amplitude and phase information is a very good choice. On the contrary, for a large number of diversity antennas in base stations, using long-term amplitude information with a sparsely quantized phase shows BER performance close to the case where full channel state information is applied.

Error rate analysis of AF-relay wireless networks under different SNR levels

This paper presents a new method for analyzing the Bit Error Rate (BER) performance of two-hop Amplify-and-Forward Multiple Relay (AF-MR) networks. This paper considers, a flat-fading channel and a relay selection scheme to select a relay with the highest Signal-to-Noise Ratio (SNR). The method aims to unify the BER calculation under low, high and optimal SNR levels. Asymptotic BER (ABER) performance at high SNR value is calculated first, and standard expressions for exact BER (EBER) performance at low and optimal SNRs are then derived. The analytic method depends on the conventional BER (CBER) approach of one-hop communication systems. The optimal SNR is obtained by balancing energy efficiency and spectral efficiency. The proposed method is found to be effective for calculating the BER of AF-MR network performance under any SNR conditions. Moreover, it improves the accuracy of ABER performance by reducing disparity computation errors between ABER and EBER performances and this allows the BER of AF-MR networks to be accurately calculated using either ABER or EBER. The outcome expressions for the method are validated by simulation results.

Bit Error Rate Comparison Statistics and Hypothesis Tests for Inverse Sampling (Negative Binomial) Experiments

Inverse, or negative binomial, sampling is often used when the observation of interest occurs extremely infrequently. As this is the case in bit error rate (BER) simulations, especially in high signal-to-noise ratio cases, negative binomial sampling can be advantageously employed in a computationally economic fashion to compare bit error rates between different systems. When the results of two negative binomial sampling tests are compared, point estimates and interval estimates quantify the performance relationship between the results of the tests. This paper derives a new, optimal, logarithmically symmetric confidence interval estimator for the ratio of BER estimates derived from two negative binomial tests. In addition, a three-sided hypothesis test with a single significance level is derived to quantify the confidence of the relationship between the two systems. Low-BER approximations for the confidence interval and decision thresholds are derived based on the F-distribution. The approximation is shown to work with BERs as high as $10^{-2}$ . An example inspired by bit interleaved coded modulation shows how the technique can be used to reduce simulation time by an order of magnitude and facilitate straightforward interpretation and comparison between different systems. Negative binomial sampling is recommended for comparison experiments where BER is the key metric.

Performance analysis of MIMO systems with arbitrary number transmit antenna selection and OSTBC in the presence of imperfect CSI

In this paper, the performance analysis of MIMO systems with arbitrary number transmit antenna selection (TAS) and orthogonal space-time block coding (STBC) in Rayleigh fading channels for imperfect channel state information (CSI) is presented. For the performance analysis, the moment generating function of the system effective SNR as well as its upper and lower bounds are derived. Then, accurate and approximate expressions of bit error rate (BER) of MIMO-TAS-STBC with MPSK and MQAM are further derived. Using the approximate BER formula and imperfect CSI, an adaptive antenna selection scheme is developed for minimizing the BER. The diversity gain and coding gain are analyzed at high SNR. The results indicate that the MIMO-TAS-STBC for imperfect CSI can only achieve partial diversity order $KN$ and the coding gain is affected by $K$, $N$, code rate, modulation pattern, and channel correlation coefficients, when $K$ transmit antennas are selected and $N$ receive antennas are used. Simulation results show that the theoretical analysis matches the simulation result well, and the approximate expressions are close to the accurate ones but have a lower complexity.

Bit error rate performance analysis in amplify-and-forward relay networks

Two methods are proposed in this paper to estimate asymptotic and exact bit error rate (BER) in two-hop amplify-and-forward (AF) relay networks . Rayleigh-fading channels are considered and selection strategy is used to select the highest end-to-end signal-to-noise ratio relay among all relays. The first presented method unifies the BER analysis performance for both one and two hop networks in one scheme and this refers to as the unified BER (U-BER) . The second method, namely the optimal BER (O-BER), is developed to measure BER for an AF relay network that is optimized with respect to its energy and spectral efficiency. Expressions for asymptotic BER performance for (U-BER) and (O-BER) are derived. An expression for the exact BER for (U-BER) is also obtained. The proposed methods provide useful and efficient tools for analyzing the BER performance in AF relay networks . Analytical and simulated results are compared to validate the BER calculation.

Continuous Control of Random Polarization Rotations for Quantum Communications

A nonintrusive technique to continuously control random polarization rotations for quantum communications is proposed. It allows an automatic control of the random polarization rotations that photons suffer during their propagation inside standard fibers, without the use of additional classical signals and hardware. The polarization control method is based on a rigorous and efficient estimation of the quantum bit error rate, derived from the Clopper–Pearson confidence interval for a binomial distribution. A system of frames with control and data qubits is employed. The number of control qubits in each frame is optimized in real time in order to minimize the system overhead.

Optimal Write Head Design for Perpendicular Magnetic Recording

Perpendicular Magnetic Recording (PMR) [1] is widely commercialized but the areal density gains for PMR are slowing down. The writer is a very important component of the magnetic recording system with many parameters that need to be optimized. The writing performance depends on many parameters and there are many metrics that could be used to predict the performance, in particular, the writer field strength and the write field gradient are two important such metrics. However, exactly how these intermediate metrics translate into areal density gain is a complex process involving improvement to the SNR and BER. Therefore, we adopt an approach to search for the optimal solution of the write head design based on the maximization of the signal-to-noise ratio (SNR) and the minimization of the bit error rate (BER) via micromagnetic simulations the grain-flipping probability (GFP) model [2] and channel simulation. We select six variables as the design parameters in the write head. An initial screen testing is performed to decide the nominal values of these parameters and their variations. The design of experiments (DOE) is conducted by applying an orthogonal array (OA) [3] and LLG-based micromagnetic simulations are carried out to obtain the magnetization distributions in the recording media for each head design. These magnetization distributions are then used to train the corresponding grain-flipped probability model (GFPs). The SNRs and BERs are obtained from processing the GFP model output with a software channel. The Taguchi method [3] is used to identify the optimal solution by maximizing the SNRs and minimizing the BERs. Using the Taguchi method, we predict the SNR and the BER at the optimal head design and finally, the verification is performed by micromagnetic simulation, GFP model, SNR characterization and BER calculation for the optimal design.

Average BER performance of FSO SIM-QAM systems in the presence of atmospheric turbulence and pointing errors

This paper presents the exact average bit error rate (BER) analysis of the free-space optical system employing subcarrier intensity modulation (SIM) with Gray-coded quadrature amplitude modulation (QAM). The intensity fluctuations of the received optical signal are caused by the path loss, atmospheric turbulence and pointing errors. The exact closed-form analytical expressions for the average BER are derived assuming the SIM-QAM with arbitrary constellation size in the presence of the Gamma–Gamma scintillation. The simple approximate average BER expressions are also provided, considering only the dominant term in the finite summations of obtained expressions. Derived expressions are reduced to the special case when optical signal transmission is affected only by the atmospheric turbulence. Numerical results are presented in order to illustrate usefulness of the derived expressions and also to give insights into the effects of different modulation, channel and receiver parameters on the average BER performance. The results show that the misalignment between the transmitter laser and receiver detector has the strong effect on the average BER value, especially in the range of the high values of the average electrical signal-to-noise ratio.