Bit Error Probability Research Articles

Mode-Locking and Noise Characteristics of InAs/InP Quantum Dash/Dot Lasers

The mode-locking and noise characteristics of InP/InAs quantum dash (QDash) and quantum dot (QDot) multi-wavelength lasers, showing identical structural design, operating at the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> -band, are investigated and compared to each other. The QDash lasers exhibit improved repetition frequency stability with a lower threshold current and cavity loss. On the other hand, the QDot lasers show higher quality repetition frequency tunability with higher internal quantum efficiency, as well as lower average integrated relative intensity noise (RIN) and average optical linewidth. Furthermore, we demonstrate both the QDash and QDot lasers exhibit very clean constellation diagrams at 32 GBaud 16QAM base-band signal, while the QDot lasers' bit-error ratio (BER) performance outperforms the QDashes. This finding highlights the viability of InAs/InP QDash/QDot lasers to be used as a low-cost optical source for large-scale networks.

Amplify-and-Forward (AF) Relay Techniques in Wireless SC-FDE Systems to Enhance Diversity Gains

This paper introduces an amplify-and-forward (AF) relaying technique that employs phase dithering and intentional delay within single carrier-frequency domain equalizer (SC-FDE) systems. The proposed relaying technique aims to increase the gain of both frequency diversity and time diversity in slow fading channels. To achieve this, the proposed technique introduces random phase rotation and random intentional delay. The relaying scenario assumes two-hop communication with relaying between the source and destination. It is assumed that many nodes are densely distributed, allowing for many relay nodes to participate in relaying. To verify the performance through computer simulation, the number of relays is 1, 2, 3, 5, 15, and 25, and three modulation coding schemes (MCSs) are considered: QPSK with R=1/3, 16QAM with R=3/4, and 8PSK with R=7/8. The simulation results demonstrate that the proposed relaying technique improves the bit error ratio (BER) performance. The performance improves as the number of relays increases.

Development of a novel RBFNN‐trained nonlinear channel equalizer based on GDEBOA technique

AbstractThe equalization of digital channels is generally known to be a nonlinear classification problem. Applications such as these can benefit from networks that approximate nonlinear mappings. It gets good performance by adjusting only one coefficient and one center closest to the input vector of the radial basis function network (RBFN), which is a simplified version of stochastic gradient techniques. Artificial Neural Networks (ANNs) are suitable for channel equalization because they have the capability to map between variables. Having only one hidden layer in Radial Basis Function Neural Network (RBFNN) makes it the most preferred equalizer to mitigate distortions in the channels. The ability to equalize nonlinear channels is strength of radial RBFNN, which is a simplified version of stochastic gradient techniques. The conventional “hit and trial” approach poses the greatest difficulty when designing RBFNN Equalizers. As a solution to these limitations, this work suggests a training strategy based on Gaussian distribution estimation strategy (GDE) in hybrid butterfly optimization algorithm (GDEBOA) for RBFNN channel equalizer. The proposed RBFNN equalizer is being trained using a population‐based optimization algorithm. An algorithm, called GDEBOA, based on a GDE approach is developed in this paper. The proposed training scheme significantly outperforms existing metaheuristic algorithms in terms of mean square error (MSE) and bit error rate (BER). Furthermore, based on burst error scenarios and bit error probability (BEP), the proposed method has demonstrated greater robustness than other methods when faced with such scenarios. The effectiveness of the suggested scheme over a wide range of signal‐to‐noise ratios has been validated by several simulation studies. Additionally, statistical importance of the suggested technique is analyzed. It is visualized that GDEBOA performs better than existing algorithms for training RBFNN equalizer.

Performance Enhancement of Chaotic Error Correction Coding Using Consecutive Sequences

The use of chaotic dynamics for error correction is the subject of extensive research, as the approach allows to avoid the use of redundant data. This work proposes a new technique for non-coherent chaos communications for modifying error-correction depending on chaotic dynamics. In the proposed system, there are two consecutive sequences created from a comparable chaotic map, with the second series being created as the latest value of the initial one. Generation of a sequential chaotic sequence with a comparable chaotic dynamic delivers additional information to the receiver, allowing it to appropriately recover information and, hence, facilitate the receiver’s bit-error performance. For error correction and for detecting the symbol that is transmitted, a suboptimal technique based on the nearest distance between chaotic map trajectories over the n-dimensional sequence received is utilized. Simulation results show that the proposed error correction approach improves Eb/N0 as the dimension of the trajectory map increases, indicating that the method improves overall error correction performance. With the dimension of 4, a gain of 0.8 dB in Eb/N0 is achieved compared with an approach without any error-correcting schemes, at the bit-error probability of 10−3.

Multifrequency Vector Mm-Wave Signal Generation with No Optical Filtering Based on One Dual-Arm MZM with Phase Factor Optimization

In order to reduce the number of devices in and cost of a multifrequency vector millimeter-wave (mm-wave) signal generation system, we propose a novel scheme for multifrequency vector mm-wave signal generation based on one dual-arm Mach-Zehnder modulator (MZM) without optical filtering. This scheme utilizes the carrier suppression modulation of a single modulator, without the need for optical filtering and combines precoding technology to generate high-frequency QPSK and 16 QAM mm-wave signals. The transmitter is applied with precoding technology to make the frequency multiplying vector mm-wave signal display regular vector modulation at the receiver, and the system is optimized with a phase factor to ensure that the phase distribution of QPSK signal at the receiver is symmetrical. We demonstrated the generation of 4-Gbaud 76 GHz QPSK and 16 QAM vector mm-wave signals through simulation. The simulation results show that, at a fiber transmission distance of 12 km, when the launched optical power of the PD is greater than −20.535 dBm, the bit error ratio (BER) of the QPSK signal is lower than the hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10−3. At a fiber transmission distance of 10 km, when the launched optical power of the PD is greater than −18.637 dBm, the BER of 16 QAM signal is also lower than 3.8 × 10−3.

C-FD MAC: Constellation based Full-Duplex MAC protocol

Simultaneous transmission and reception of data packets in Full-Duplex (FD) communication can theoretically double the system throughput. However, efficient self-interference mitigation and symbol detection at the receiver is required to realize the full potential of FD communication in practical scenarios. In this paper, we propose a constellation-based FD medium access control (MAC) protocol (C-FD) for wireless local area networks (WLAN). In the proposed C-FD MAC protocol, the node and Access Point (AP) can exchange packets simultaneously by transmitting the symbols and using different modulation schemes. The superimposed constellation diagram has been used to decode the symbols efficiently at both ends. The novel feature of the C-FD MAC protocol is that it does not require any complicated interference cancellation techniques. The analytical results for Symbol Error Rate (SER), Packet Error Rate (PER), and throughput have been derived for the symmetrical and asymmetrical FD link considering the additive white Gaussian noise (AWGN) with Rayleigh fading. The proposed C-FD MAC protocol achieves nearly twice the throughput compared to Half duplex (HD) communication without compromising the SER. The analytical results have been validated with extensive simulation.

Tbit/s line-rate satellite feeder links enabled by coherent modulation and full-adaptive optics

Free-space optical (FSO) communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks. They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations. Here, we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top (3700 m) in the Swiss Alps and the Zimmerwald Observatory (895 m) near the city of Bern, achieving net-rates of up to 0.94 Tbit/s. With this scenario a satellite-ground feeder link is mimicked under turbulent conditions. Despite adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation formats. It was found that adaptive optics does not distort the reception of coherent modulation formats. Also, we introduce constellation modulation – a new four-dimensional BPSK (4D-BPSK) modulation format as a technique to transmit high data rates under lowest SNR. This way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit, respectively, at a bit-error ratio of 1 ∙ 10−3. The experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.

100 Gbit/s PAM-4 Linear Burst-Mode Transimpedance Amplifier for Upstream Flexible Passive Optical Networks

Next-generation passive optical networks (PONs) with upstream rates of 50 Gbit/s and beyond will require a new class of burst-mode transimpedance amplifiers (BMTIAs) that are linear to enable (digital) equalization of channel impairments. Such linear BMTIAs also enable higher-order modulation formats like 4-level pulse amplitude modulation (PAM-4). In this paper, we demonstrate operation of a novel linear BMTIA integrated together with a commercial off-the-shelf 25G-class avalanche photodiode (APD), achieving 50 Gbit/s non-return-to-zero (NRZ) operation with a sensitivity of -23.7 dBm optical modulation amplitude (OMA) and dynamic range exceeding 21.7 dB and 100 Gbit/s PAM-4 operation with a sensitivity of -15.8 dBm OMA and dynamic range exceeding 15.4 dB, both at a bit error ratio (BER) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10^{-2}$</tex-math></inline-formula> . In addition, fast burst-mode gain-control and balancing circuits limit loud-soft sensitivity penalties in the case of AC-coupled circuits to less than 1.3 dB. The chip was designed in a 0.13 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m SiGe:C BiCMOS technology, has an area of 1.2×1.7 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> and consumes between 260 mW and 310 mW. This receiver paves the way to a next-generation class of BMTIAs, supporting the ITU-T G.9804.3 Amd 1 standard.

Dynamic analysis of PAM-4 IM/DD OAM-based MGDM transmission enabled by mode-group filter approach.

Mode-group-division multiplexing (MGDM)-based intensity modulation direct detection (IM/DD) transmission is an attractive approach to increase the capacity for short-reach optical communication. In this Letter, a simple but versatile scheme of mode group (MG) filtering for MGDM IM/DD transmission is proposed. The scheme is applicable to any mode basis in the fiber, and it satisfies the needs of low complexity, low power consumption, and high system performance. By employing the proposed MG filter scheme, a total raw bit rate of a 152-Gb/s multiple-input-multiple-output (MIMO)-free IM/DD co-channel simultaneous transmit and receive system based on two orbital angular momentum (OAM) MGs, each carrying a 38-GBaud four-level pulse amplitude modulation (PAM-4) signal, is experimentally demonstrated over a 5-km few-mode fiber (FMF). The bit error ratios (BERs) of the two MGs are below the 7% hard-decision forward error correction (HD-FEC) BER threshold at 3.8×10-3, using simple feedforward equalization (FFE). Furthermore, the dependability and robustness of such MGDM links are of great significance. Thus, the dynamic evaluation of BER and signal-to-noise ratio (SNR) for each MG is tested over 210 minutes under different conditions. In the dynamic cases, all the BER results using the proposed scheme can be below 1×10-3, which further confirms the stability and feasibility of our proposed MGDM transmission scheme.

Generation of high-speed PAM-4 signal with 3-bit DAC enabled by CRD-NS in optical interconnect.

In this paper, we experimentally demonstrated a 2-km high-speed optical interconnection with pulse-shaped pre-equalized four-level pulse amplitude modulation (PAM-4) signal generated by a 3-bit digital-to-analog converter (DAC) with the aid of in-band quantization noise suppression techniques under different oversampling ratios (OSRs) to reduce the influence of quantization noise. The simulation results show that the quantization noise suppression capability of high computational complexity digital resolution enhancer (DRE) is sensitive to taps number of the estimated channel and match filter (MF) response when OSR is sufficient, which will lead to further significant computational complexity increase. To better accommodate this issue, channel response-dependent noise shaping (CRD-NS) which also takes channel response into consideration when optimizing quantization noise distribution is proposed to suppress the in-band quantization noise instead of DRE. Experimental results show that about 2 dB receiver sensitivity improvement can be achieved at the hard-decision forward error correction (HD-FEC) threshold for 110 Gb/s pre-equalized PAM-4 signal generated by 3-bit DAC when the traditional NS technique is replaced by the CRD-NS technique. Compared to the high computational complexity DRE technique, in which channel response is also considered, negligible receiver sensitivity penalty is observed for 110 Gb/s PAM-4 signal, when the CRD-NS technique is utilized. Considering both the system cost and bit error ratio (BER) performance, the generation of high-speed PAM signal with 3-bit DAC enabled by the CRD-NS technique is regarded as a promising scheme for optical interconnection.

On Detection of Anomalous VHF Propagation over the Adriatic Sea Utilising a Software-Defined Automatic Identification System Receiver

This paper represents observations on detection of Very High Frequency (VHF) anomalous propagation over the area of the Adriatic Sea. During the research campaign, a Software Defined Radio (SDR) Automatic Identification System (AIS) receiver was employed for collection of AIS data packets at a fixed location in the Northern Adriatic. Data were collected during the 24-h period (25 February 2023 15:32 LT to 26 February 2023 15:32 LT), providing information from 115 AIS targets, or 159 965 AIS packets with 54.3% Packet Error Rate (PER), respectively. Subsequent analysis and post-processing of successfully demodulated signals and decoded packets was presented further. In certain instances, the SDR AIS receiver detected, received and decoded data packets from AIS targets distant several orders of magnitude larger than the VHF nominal ranges. To determine the magnitude of line-of-sight and over-the-horizon radio waves propagation, the great circle distances between the SDR AIS receiver antenna and AIS packets’ decoded positions were calculated, revealing hundreds of Nautical Miles (NM). Possible reasons for these occurrences, including tropospheric scattering, diffraction, ionospheric sporadic E layer and refraction were discussed and evaluated, in accordance, among others, with the previous research. By exclusion criteria and neglection of possible causes, it was concluded that the enhanced, over-the-horizon propagation of AIS signals occurred as a result of refraction effects, namely trapping/ducting, subrefraction and superrefraction. Data from nine World Meteorological Organization (WMO) radiosondes surrounding the greater reception area were collected for the same observation periods. Atmospheric profiles were created using Advanced Refractive Effects Prediction System (AREPS) program, and analysed for each individual station measurement. The results confirmed anomalous, over-the-horizon enhanced propagation and their probable origins, i.e., the occurrence of refractive conditions in the atmosphere over the Adriatic Sea area. These findings provide a solid foundation for further research in the area of propagation of VHF signals and their anomalous features caused by the atmospheric phenomenon effects.

Decision Algorithm Based on the Modified Bellman Equation to Deal With EMI-Induced Errors in Hamming-Based Communications

This article presents a decision-making algorithm based on a modified version of the Bellman equation to deal with electromagnetic interference errors in a communication channel inside a harsh electromagnetic reverberant environment. The Bellman equation is a fundamental concept in decision-making problems such as Markov decision processes. Such processes model decision making in situations where the outcomes are partly random and partly controlled by an agent (decision maker). Recent studies have implemented Markov decision processes as a tool for risk assessment in areas such as robotics or aviation. However, so far, no research has been reported that uses the Bellman equation or Markov decision processes to deal with risks related to electromagnetic disturbances. In our study, a wired communication channel that uses non-return-to-zero-level data encoding and Hamming code for error detection and correction is disturbed. First, the packet error rate (PER) is calculated and compared with and without the proposed algorithm for different electromagnetic disturbance frequencies and bit rates. The gain is compared at different PERs when the algorithm's parameters (called rewards) are optimized and when these are set as random. Finally, the influence of the rewards and the maximum number of resends on the algorithm's performance is also studied.

Performance Analysis of SIMO–OFDM Systems With Pilot-Aided Channel Estimation

Pilot symbols are commonly modulated on uniformly spaced subcarriers to aid channel estimation, thereby facilitating data demodulation in practical orthogonal frequency-division multiplexing (OFDM) systems operating over quasi-static multipath channels, where the channel frequency response (CFR) remains static within one block. Aided by uniformly spaced pilot symbols, the direct least-square CFR estimation can enable reliable symbol-by-symbol data demodulation within the same OFDM block, based on the principle of generalized likelihood ratio test (GLRT). Such GLRT-based OFDM can be easily incorporated with single-input multiple-output (SIMO) antenna technique to enhance data demodulation over quasi-static channels exhibiting random multipaths. In this article, an upper bound to the average bit error probability (BEP) is analytically derived for this GLRT-based SIMO&#x2013;OFDM system over quasi-static random multipath channels. The analysis is generally applicable to arbitrary two-dimensional component modulations when the quasi-static SIMO channel consists of independent but not necessarily identically distributed random channel paths with Rician or Rayleigh distributed path response magnitudes. The BEP upper bound facilitates the error performance characterization of the GLRT-based SIMO&#x2013;OFDM system with respect to data-to-noise power ratio, data-to-pilot power ratio, antenna diversity, pilot density, and pilot power allocation.

Performance analysis of a NOMA-VLC system with random user location

In this paper, we investigate the performance of a downlink non-orthogonal multiple access (NOMA) based visible light communication (VLC) system. We consider that the users are randomly located following a binary Poisson point (BPP) Process. The performance of the considered system is evaluated by deriving novel closed-form expressions of the bit error ratio (BER) and ergodic sum rate. The impact of an error due to the successive interference cancellation (SIC) is also taken into consideration in the BER analysis. The obtained results with respect to different system parameters are instrumental to provide useful insights into the system performance.

Ultra-Sensitive PIN-Photodiode Receiver

A monolithically integrated receiver consisting of a low-capacitance PIN photodiode and a photo-charge integrating amplifier in 0.18- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m CMOS is introduced launching a new class of ultra-sensitive optical receivers. The integrated PIN photodiode has a junction capacitance of 1.5 fF at a light-sensitive diameter of 30 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m, a responsivity of 0.39 A/W at 635 nm, and rise/fall times of 0.73/0.92 ns at a reverse bias of 20 V. The common-source amplifier integrates the photo-charges on the smallest possible integration capacitor, which is a gate-drain overlap capacitance. The data bits are reconstructed by double sampling. In such a way, the sensitivity of SPAD receivers is achieved, however without using any impact ionization. At 50 Mb/s, a sensitivity of −56.4 dBm for a bit error ratio (BER) of 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> is obtained using a wavelength of 635 nm.

Joint Optimization of OFDM and Channel Coding for URLLC in Industrial Channels

Industrial communications have very tight requirements of reliability and latency, which are challenging to achieve at highly dynamic industrial radio channels. Redundancy in the modulation and coding can improve reliability but incurs excess latency. Minimizing latency subject to reliability constraint for a given channel state opens up the scope for static and runtime optimization. In this paper we explore joint optimal configuration of Orthogonal Frequency Division Multiplexing (OFDM) and channel coding, using polar, Low Density Parity Check (LDPC) and convolutional codes to minimize the transmission time subject to a maximum acceptable packet error rate, for three realistic channels reported by National Institute of Standards and Technology, using channel impulse response measurements, as well as perfect and imperfect channel estimation. The results show that the use of strong channel codes can significantly reduce transmission time, by up to 24% compared to convolutional codes, with LDPC achieving fastest transmission. For transmission times of 10-20 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> s the contribution of the Cyclic Prefix (CP) is significant, up to 30% for convolutional codes. Stronger channel codes allow reduced CP, even considering the added redundancy such as Cyclic Redundancy Check (CRC), resulting in overall lower transmission time. The decoding time also introduces significant overheads, up to 50% of transmission time for polar codes. The paper also investigates the impact of channel estimation errors, which adversely impact Ultra-Reliable Low-Latency performance: lower bound errors violate the reliability constraint and higher bound errors introduce excess transmission times.

Millimeter-wave channel modeling in a VANETs using coding techniques.

The Vehicular ad-Hoc Network (VANET) is envisioned to ensure wireless transmission with ultra-high reliability. In the presence of fading and mobility of vehicles, error-free information between Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) requires extensive investigation. The current literature lacks in designing an ultra-reliable comprehensive tractable model for VANET using millimeter wave. Ultra-reliable communication is needed to support autonomous vehicular communication. This article aims to provide a comprehensive tractable model for VANET over millimeter waves using Space-Time-Block-Coding (STBC) concatenated with Reed Solomon (RS) coding. The designed model provides the fastest way of designing and analyzing VANET networks on 60 GHz. By using the derived BER expressions and Reed Solomon coded doppler expression ultra-reliable vehicular networks can be build meeting the demands of massive growing volume of traffic. The performance of the model is compared with previous BER computational techniques and existing VANET communication systems, i.e., IEEE 802.11bd and 3rd generation partnership project vehicle to everything (3GPP V2X). The findings show that our proposed approach outperforms IEEE 802.11bd and the results are comparable with V2X NR. Packet Error Rate (PER), Packet Reception Ratio (PRR) and throughput are used as performance metrics. We have also evaluated the model on higher velocities of vehicles. Further, the simulation and numerical findings show that the proposed system surpass the existing BER results comprising of various modulation and coding techniques. The simulation results are verified by the numerical results there-by, showing the accuracy of our derived expressions.

ВЛИЯНИЕ ЧАСТОТНОГО ШУМА В КАНАЛЕ СВЯЗИ НА ВЕРОЯТНОСТЬ БИТОВОЙ ОШИБКИ ПРИ ПЕРЕДАЧЕ КАМ СИГНАЛОВ

The purpose of the article is to analyze the combined effect of amplitude white Gaussian noise(AWGN) present in the communication channel and frequency noise (FN) resulting from fluctuations inthe frequency of the signal in the communication channel on the probability of bit error when processingQAM signals. Research tasks to be solved: 1. Development of a mathematical model for processing theQAM signal, taking into account the combined effects of AWGN and FN in the communication channel.2. Numerical study of the combined effect of AWGN and FN on the probability of bit error when processingQAM signals. A mathematical model is proposed that establishes the relationship between thesignal-to-noise ratio in the channel and the mean square deviation of the signal frequency, on the onehand, and the probability of bit error during A mathematical model is proposed that establishes therelationship between the signal-to-noise ratio in the channel and the mean square deviation of the signalfrequency, on the one hand, and the probability of bit error during QAM signal demodulation, on theother. The visualization of the effects associated with the presence of AWGN and FN in the channel onthe signal constellation of the received QAM signal is given. The main patterns associated with jointaction AWGN and FN in the communication channel are: - the appearance of FN in the communicationchannel leads to a decrease in the signal level in the channel during the correlation processing of thereceived signal and a corresponding decrease in SNR; - In addition to the blurring of the signal constellationin the azimuthal direction, associated with the appearance of an integral phase fluctuation due tofrequency fluctuations during the pulse, an increase in the blurring of the signal constellation in theradial direction causes a decrease in the SNR. Based on the results obtained, it is concluded that it isnecessary to take into account more fully the deviations of the signal parameters in the channel due toboth the presence of AWGN and FN.

Experimental Performance Analysis of Hardware-Based Link Quality Estimation Modelling Applied to Smart Grid Communications

The smart grid is the modern electricity grid, which significantly improves the efficiency, reliability, and sustainability of electricity transmission systems. The advanced metering infrastructure (AMI) system, which is the essential system in the smart grid, enables real-time data collection and data analysis obtained from smart meters (SMs) and other devices through last-mile communication networks. In this paper, the hardware-based link quality estimation (LQE) was modeled, namely an SNR-based model, a mapping model, and an RSSI- and PRR-based logistic regression model, and their performance was then evaluated by the root mean-squared error (RMSE) with the empirical data. The SNR-based and mapping models were formulated by the packet error probability, whereas the RSSI- and PRR-based logistic regression model was formulated by the empirical data fitting. The RSSI- and PRR-based logistic regression model outperformed the other two models, with an RMSE difference of 111–122%. These LQE models can be implemented on SMs or modems to monitor the reliability and efficiency of the AMI last-mile communication network.

On the performance stability of MCF-based SDM system affected by inter-core crosstalk fluctuation.

The inter-core crosstalk (IC-XT) of multi-core fiber (MCF) limits the capacity of space division multiplexing system (SDM) fundamentally. We develop a closed-form expression of the magnitude of IC-XT for various types of signals, which can well explain the mechanism of different fluctuation behaviors of the real-time short-term average crosstalk (STAXT) and bit error ratio (BER) for the optical signals with and without strong optical carrier. The experimental verifications with the real-time measurement of the BER and outage probability in a 7 × 10-Gb/s SDM system agree well with the proposed theory and confirm that the unmodulated optical carrier plays a substantial role in fluctuation of BER. The range of fluctuation can be reduced by 3 orders of magnitude for the optical signal without optical carrier. We also investigate the effect of IC-XT in a long-haul transmission system based on a recirculating 7-core fiber loop and develop a frequency-domain IC-XT measurement technique. Longer transmission distance is shown to have a narrower BER fluctuation range, since IC-XT is no longer the only dominant factor on transmission performance.