Maximum Information Rate Research Articles

A Neurodynamic Approach for SWIPT Power Splitting Optimization

Simultaneous wireless information and power transfer (SWIPT) systems using energy from RF signals can effectively solve the energy shortage of wireless devices. However, the existing SWIPT optimization methods using numerical algorithms are difficult to solve the non-convex problem and to adapt to the dynamic communication circumstances. In this paper, a duplex neurodynamic optimization method is used to address the SWIPT system’s power partitioning issue. The information rate maximization problem of the SWIPT system is framed as a biconvex problem. A duplex recurrent neural network is used to concurrently execute local search and update the initial state of the neural network by a particle swarm optimization method to get the global optimum. The experimental results demonstrate that the duplex neurodynamic-based SWIPT system maximizes information rate while satisfying the minimal harvesting energy requirement in a variety of channel states.

On Quaternion Modeling and Kalman Filtering from Vector Observations

This paper presents novel results on quaternion state-space modeling and estimation from rate gyro measurements and vector observations. The spectral properties of the Lyapunov differential equation for the quaternion second-order moment are investigated and expressions for its solution are developed. The properties of a four-dimensional rank-degenerate measurement model of the quaternion are analyzed. Four different approaches are suggested in order to reduce the dimension of the measurement equation, hinging on information optimization or on the spectral properties of the measurement matrix. While the measurement dimension’s reduction saves computations, it does not impair the exact statistical treatment of state-dependent process and measurement noises. As a result, the proposed filters are optimal and statistically consistent without tuning. The performance of the maximum information rate quaternion filter is verified via extensive Monte Carlo simulations. The test cases of spinning and rapidly tumbling rotations of a small satellite on a low Earth orbit are simulated. The filters process measurements of the sun vector, of the Earth magnetic field, and of rate gyros. The novel filters converge where a standard extended Kalman filter fails to do so under similar conditions.

Blind Carrier Phase Recovery Using Extended Kalman Filtering in Probabilistically Shaped Coherent Systems

In this paper, we propose an Extended Kalman Filtering with phase noise reconstruction (EKF-PC) scheme to enhance the carrier recovery capability for probabilistic shaping of coherent optical communication systems with various shaping factors. We first investigate the weights of the shaping factor and the noise rejection window length of EKF-PC for PS-64QAM at a fixed signal-to-noise ratio (SNR). After that, we jointly optimize the shaping factor and the noise rejection window length to obtain the maximum achievable information rate at a variety of SNRs. Then, we numerically analyze the carrier recovery performance of the EKF-PC for different linewidths and SF conditions. Finally, we conduct simulation experiments to compare EKF-PC, PCPE, and other currently available Kalman CPE algorithms with the SFs of 0.02, 0.025, 0.03, and 0.035 under back-to-back (B2B) scenarios. The experimental results show that EKF-PC obtains an average SNR improvement of 0.13–0.5 dB compared to PCPE and an average performance improvement of 0.5–1 dB compared to other Kalman algorithms.

Lower Bound on the Capacity of the Continuous-Space SSFM Model of Optical Fiber

The capacity of a discrete-time model of optical fiber described by the split-step Fourier method (SSFM) as a function of the signal-to-noise ratio SNR and the number of segments in distance K is considered. It is shown that if K ≥ SNR2/3 and SNR → ∞, the capacity of the resulting continuous-space lossless model is lower bounded by 1/2 log2(1 + SNR) - 1/2 + o(1), where o(1) tends to zero with SNR. As K → ∞, the inter-symbol interference (ISI) averages out to zero due to the law of large numbers and the SSFM model tends to a diagonal phase noise model. It follows that, in contrast to the discrete-space model where there is only one signal degree-of-freedom (DoF) at high powers, the number of DoFs in the continuous-space model is at least half of the input dimension n. Intensity-modulation and direct detection achieves this rate. The pre-log in the lower bound when K=δ√SNR is generally characterized in terms of δ. It is shown that if the nonlinearity parameter γ → ∞, the capacity of the continuous-space model is 1/2 log2(1 + SNR) + o(1). The SSFM model when the dispersion matrix does not depend on K is considered. It is shown that the capacity of this model when K=δ√SNR, δ > 3, and SNR → ∞ is 1/2n log2(1 + SNR) + O(1). Thus, there is only one DoF in this model. Finally, it is found that the maximum achievable information rates (AIRs) of the SSFM model with back-propagation equalization obtained using numerical simulation follows a double-ascent curve. The AIR characteristically increases with SNR, reaching a peak at a certain optimal power, and then decreases as SNR is further increased. The peak is attributed to a balance between noise and stochastic ISI. However, if the power is further increased, the AIR will increase again, approaching the lower bound 1/2 log(1 + SNR) - 1/2 + o(1). The second ascent is because the ISI averages out to zero with K → ∞ sufficiently fast.

Maximizing Fiber Capacity in Flex-Grid Coherent Systems Through Symbol Rate Optimization

We demonstrate that, in an actual network, maximizing the transmission spectral efficiency requires not only to take into account transceiver impairments, but also to consider WSS filtering and flex-grid specifications. In a WDM transmission experiment over a 10-span link covering <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 38$ </tex-math></inline-formula> nm, we study achievable rate, bitrate and spectral efficiency for different symbol rates of 62.5, 75, 87.5, 100 and 112.5Gbaud with corresponding channel spacings of 75, 87.5, 100, 112.5, 125GHz, therefore accounting for few GHz bandguard required for potential WSS filtering effect, as well as being compatible with flex-grid configuration. While maximum achievable information rate per transceiver (wavelength) is achieved for the lowest symbol rate, and operating at larger symbol rate maximizes the bitrate per wavelength, to maximize overall fiber spectral efficiency (and therefore, capacity), operation at intermediate symbol rates, from 75 to 100Gbaud in our study, is required as a trade-off between the penalties from transceiver impairments and WSS filtering.

Maximum probability directed blind phase search for PS-QAM with variable shaping factors.

We report the maximum probability directed blind phase search (MPD-BPS) solution to enhance the carrier phase estimation (CPE) capability for the probabilistically shaped-quadrature amplitude modulation (PS-QAM) with variable shaping factors. We first investigate the trade-off between the shaping factor (SF) and the noise rejection window of the BPS for the PS-64/256QAM at a fixed signal to noise ratio (SNR). Next, we carry out the joint optimization of the SF and the noise rejection window, in order to obtain the maximum achievable information rate (AIR) at the fixed SNR. Then, we numerically compare the performance of the MPD-BPS and the traditional BPS for the PS-64/256QAM with variable SFs. Finally, we conduct the experimental verification of 32 Gbaud PS-64QAM with the SFs of 0.02, 0.025, 0.03, and 0.035, under scenarios of back-to-back (B2B) transmission and the standard single mode fiber (SSMF) loop transmission. The experimental results indicate that the proposed MPD-BPS can obtain an average 0.13 dB SNR enhancement under the B2B transmission and the 1.67% reach enhancement for the SSMF transmission, in comparison with the use of traditional BPS.

Capacity of underwater optical wireless communication systems over salinity-induced oceanic turbulence channels with ISI.

Point-to-point underwater optical wireless communication (UOWC) links are mainly impaired by scattering due to impurities and turbidity in the open water, resulting in a significant inter-symbol interference (ISI) that limits seriously both channel capacity and the maximum practical information rate. This paper conducts, for the first time, the channel capacity analysis of UOWC systems in the presence of ISI and salinity-induced oceanic turbulence when the undersea optical channel is accurately modeled by linear discrete-time filtering of the input symbols. In this way, novel upper and lower bounds on channel capacity and mutual information are developed for non-uniform on-off keying (OOK) modulation when different constraints are imposed on the channel input. The results show that the capacity-achieving distribution, which is computed through numerical optimization, is discrete and depends on the optical signal-to-noise-ratio (SNR). Moreover, a non-uniform input distribution significantly improves the channel capacity of such systems affected by ISI and oceanic turbulence, especially at low optical SNR. Monte Carlo techniques are employed to test the developed bounds for different undersea optical channels with one, two and three casual ISI coefficients.

M-BCJR algorithm with channel shortening based on ungerboeck observation model for faster-than-Nyquist signaling

The M-BCJR algorithm based on the Ungerboeck observation model is a recent study to reduce the computational complexity for faster-than-Nyquist (FTN) signaling [1]. In this paper, we propose a method that can further reduce the complexity with the approximately same or better bit error rate (BER) performance compared to [1]. The information rate (IR) loss for the proposed method is less than 1% compared to the true achievable IR (AIR). The proposed improvement is mainly by introducing channel shortening (CS) before the M-BCJR equalizer. In our proposal, the Ungerboeck M-BCJR algorithm and CS can work together to defeat severe inter-symbol interference (ISI) introduced by FTN signaling. The ISI length for the M-BCJR algorithm with CS is optimized based on the criterion of the IR maximization. For the two cases τ = 0.5 and τ = 0.35, compared to Ungerboeck M-BCJR without CS benchmark [1], the computational complexities of Ungerboeck M-BCJR with CS are reduced by 75%. Moreover, for the case τ = 0.35, the BER performance of Ungerboeck M-BCJR with CS outperforms that of the conventional M-BCJR in [1] at the low signal to noise ratio region.

Time–space MIMO system with faster-than-nyquist signaling in frequency-selective fading channel

The time–space receive transformation (TSRT) is proposed to increased the achievable rate of the time–space multiple-input-multiple-output (MIMO) system (where the signals received at different time instants and spatial spots are jointly processed) with faster-than-Nyquist (FTN) signaling (where the symbol rate is higher than the Nyquist rate) in the frequency-selective fading channel. It is shown that for the TSRT base MIMO system with FTN signaling, the interference from other blocks can be ineffective so that its achievable rate increases with the ratio of the symbol rate to the Nyquist rate and can reach the maximal information rate of the time–space MIMO system. It is also shown that with FTN signaling, the achievable rate of the TSRT base MIMO system is larger than that of the trailing-zeros based MIMO system and the OFDM based MIMO system, and the ratio of the symbol rate to the Nyquist rate increases this advantage.

Huffman-Coded Sphere Shaping for Extended-Reach Single-Span Links

Huffman-coded sphere shaping (HCSS) is an algorithm for finite-length probabilistic constellation shaping, which provides nearly optimal energy efficiency at low implementation complexity. In this paper, we experimentally study the nonlinear performance of HCSS employing dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) in an extended-reach single-span link comprising 200 km of standard single-mode fiber (SSMF). We investigate the effects of shaping sequence length, dimensionality of symbol mapping, and shaping rate. We determine that the naive approach of Maxwell–Boltzmann distribution matching — which is optimal in the additive white Gaussian noise channel — provides a maximum achievable information rate (AIR) gain of 0.18 bits/4D-symbol with respect to uniform signaling at optimum launch power in the infinite length regime. Conversely, HCSS can achieve a gain of 0.37 bits/4D-symbol over uniform signaling using amplitude sequence length of 32, which may be implemented without multiplications, using integer comparison and addition operations only. Coded system performance, with a net data rate of approximately 425 Gb/s for both shaped and uniform inputs, is also analyzed.

Coded modulation faster-than-Nyquist transmission with precoder and channel shortening optimization

Faster-than-Nyquist (FTN) signaling can improve the spectrum efficiency (SE) of the transmission system. In this paper, we propose a coded modulation FTN (CM-FTN) transmission scheme with precoder and channel shortening (CS) optimization to improve bit error rate (BER) performance and reduce the complexity of FTN equalizer. In our proposal, the information rate (IR) or spectral efficiency (SE) is employed and verified as a better performance metric for CM-FTN than the minimum Euclidian distance (MED). The precoder of CM-FTN is optimized for maximizing the IR criterion using the bare-bones particle swarm optimization (BB-PSO) algorithm. Further, a three-carrier CM-FTN system model is used to capture the broadening effect of precoder. Also targeting for the IR maximization, the inter-symbol interference (ISI) length for CS is optimized to reduce the receiver complexity without performance loss. Simulation results demonstrate that our method has a 0.6dB precoding gain compared with the non-precoding scheme and a maximum of 87.5% of the complexity of FTN equalizer is reduced without BER loss.

Relaying Energy Allocation Scheme Based on Multi-User SWIPT Relaying System

This paper investigates the relay energy allocation scheme based on the time switching (TS) operation strategy in multi-user simultaneous wireless information and power transfer (SWIPT) relaying system, where the relay is energy-constrained and utilizes the energy harvested in the energy harvesting mode to amplify and forward the information of the users. In the multi-user relaying system, the distances of the receivers of the users to the relay may be different. Thus, the total information rate maximization model is proposed and the corresponding energy allocation scheme is derived. After comparing the information rates of users, it is found that the information rates of users who are far from the relay are significantly lower than those of users who are close to the relay, i.e., “far-near” phenomenon. For the “far-near” problem, we propose the common information rate maximization model, and derive the corresponding energy allocation scheme. In this model, the information rates of all users are equal, which ensures the fairness of the information rate in multi-user relaying communication system. The simulation results show that the energy allocation scheme based on the common information rate maximization model can effectively solve the “far-near” problem in multi-user relaying communication system.

Molecular communication in three-dimensional diffusive channel with mobile nanomachines

A three-dimensional (3-D) diffusive mobile-molecular communication system is considered inside the unbounded environment. We consider a point transmitter and a perfectly absorbing spherical receiver which can move randomly in any of the three coordinates. The closed-form expression for expected hitting rate for 3-D unbounded communication channel with nanomachines mobility is derived. The performance of considered system is further evaluated in terms of probability of detection (PD), probability of false alarm (PFA), and probability of error (Pe). The system is further analyzed in terms of average mutual information and average maximum achievable rate. Furthermore, an optimum decision threshold, at which minimum probability of error and maximum information rate occur is also derived. The analytical results are verified through particle-based and Monte-Carlo simulations.

ANALYSIS OF THE TRANSMISSION RELIABILITY BETWEEN CONTROL SYSTEMS DEVICES WHEN ERRORS ARE PACKAGED

Context. The reliability indicators of information transmission between control systems elements, taking into account the packaging (grouping) of errors in the communication channel, are analyzed. The research object are the characteristics and parameters of noise stability cyclic binary and non-binary codes for the correction of error packets. The research subject is a theoretical and experimental comparative analysis of the reliability indicators of codes for correcting error packets. Objective. The purpose of the work is to determine the analytical dependencies of the reliability indicators of the selected redundant codes from their parameters and the communication channel properties develop models for their experimental research, formulate recommendations for choosing codes with preset characteristics with certain properties, and an error description model. Methods. The math methods and building theory of noise stability cyclic binary (BCH) and non-binary (Reed-Solomon) codes are used. The analytic formulas for determination of reliability indicators taking into account bits distortions within error packet are received. The dependencies for corrective properties and correct transmission probability form codes and error parameters are researched, the illustrating examples are shown. The simulation circuit design models for control systems with researched methods of noise stability encoding are developed. The experimental research has been done, based on the results, conclusions and recommendations for choice of code parameters for preset reliability indicators for providing of maximum efficiency (information rate) are made. Results. The dependencies of the reliability indicators (correct transmission probability) and the corrective properties (the length of corrected errors packet) from its parameters (the number of redundancy symbols, the interleaving degree – for BCH-codes; the Galua field module, number of corrected errors – for Reed-Solomon codes) are received. The recommendations of using the received results for code parameters choice are given. Conclusions. The performed researches allows calculate and reasonably choose of redundancy codes parameters for preset reliability indicators и the behavior model of errors within the communication channel. It makes possible to design and implement reliable control systems with preset reliability indicators and maximum information rate.

Fundamental Limits, Bandwidth, and Information Rate of Electrically Small Antennas: Increasing the Throughput of an Antenna Without Violating the Thermodynamic Q-Factor

The fundamental limits of antennas tie its electrical size to its quality factor (Q-factor) and radiation efficiency. The Q-factor is linearly proportional to the inverse of the instantaneous bandwidth for a narrow-band antenna. However, the thermodynamic definition of the Q-factor is equal to the ratio of stored energy to the dissipated power per cycle multiplied by 2p. In this definition, the frequency and type of stored energy are not considered; therefore, one can transmit information by modulating the frequency and/or type of stored energy, while maintaining the total stored energy with a rate higher than that which is restricted by fundamental limits. In this article, we show that instantaneous bandwidth does not necessarily define the maximum information rate of an antenna. Different techniques for transmitting a high-information-rate signal using a narrow-band (high-Qfactor) antenna are presented from an energy balance and thermodynamic point of view. A few examples are presented as proof of concept. To help with understanding this concept, we have applied some of the proposed modulation schemes to a pendulum system as a second-order mechanical resonator. Finally, the proposed modulation techniques are confirmed using simulations.

On the performance of two‐user full‐duplex network‐coded cooperation

SummaryIn this paper, we propose two schemes based on a full‐duplex network‐coded cooperative communication (FD‐NCC) strategy, namely, full‐duplex dynamic network coding (FD‐DNC) and full‐duplex generalized dynamic network coding (FD‐GDNC). The use of full‐duplex communication aims at improving the spectrum efficiency of a two‐user network where the users cooperatively transmit their independent information to a common destination. In the proposed FD‐NCC schemes, the self‐interference imposed by full‐duplexing is modeled as a fading channel, whose harmful effect can be partially mitigated by interference cancellation techniques. Nevertheless, our results show that, even in the presence of self‐interference, the proposed FD‐NCC schemes can outperform (in terms of outage probability) the equivalent half‐duplex network‐coded cooperative (HD‐NCC) schemes, as well as traditional cooperation techniques. Moreover, the ϵ‐outage capacity, that is, the maximum information rate achieved by the users given a target outage probability, is evaluated. Finally, we examine the use of multiple antennas at the destination node, which increases the advantage of the FD‐NCC (in terms of the diversity‐multiplexing trade‐off and ϵ‐outage capacity).

Intelligent Municipal Heritage Management Service in a Smart City: Telecommunication Traffic Characterization and Quality of Service

The monitoring of cultural heritage is becoming common in cities to provide heritage preservation and prevent vandalism. Using sensors and video cameras for this task implies the need to transmit information. In this paper, the teletraffic that cameras and sensors generate is characterized and the transmissions’ influence on the municipal communications network is evaluated. Then, we propose models for telecommunication traffic sources in an intelligent municipal heritage management service inside a smart sustainable city. The sources were simulated in a smart city scenario to find the proper quality of service (QoS) parameters for the communication network, using Valencia City as background. Specific sensors for intelligent municipal heritage management were selected and four telecommunication traffic sources were modelled according to real-life requirements and sensors datasheet. Different simulations were performed to find the proper CIR (Committed Information Rate) and PIR (Peak Information Rate) values and to study the effects of limited bandwidth networks. Packet loss, throughput, delay, and jitter were used to evaluate the network’s performance. Consequently, the result was the selection of the minimum values for PIR and CIR that ensured QoS and thus optimized the traffic telecommunication costs associated with an intelligent municipal heritage management service.

Information Transmission in Dynamical Networks: The Normal Network Case.

Reliable information processing is a hallmark of many physical and biological networked systems. In this paper, we propose a novel framework for modelling information transmission within a linear dynamical network. Information propagation is modelled by means of a digital communication protocol that takes into account the realistic phenomenon of inter-symbol interference. Building on this framework, we adopt Shannon information rate to quantify the amount of information that can be reliably sent over the network within a fixed time window. We investigate how the latter information metric is affected by the connectivity structure of the network. Here, we focus in particular on networks characterized by a normal adjacency matrix. We show that for such networks the maximum achievable information rate depends only on the spectrum of the adjacency matrix. We then provide numerical results suggesting that non-normal network architectures could benefit information transmission in our framework.

Concept of Analysis and Implementation of Burst On Mikrotik Router

Implementation of bandwidth management by optimizing the use of existing facilities and features, is a way / effort improvements to the quality of service on the network (Quality of Service). Mikrotik router has queue facility that can make bandwidth allocation arrangement for each user computer with analysis and application of careful burst calculation. Burst is a feature of the mikrotik router that allows a user’s computer to gain more than Maximum Information Rate (MIR) bandwidth allocation in a given time period. In this research we analyze burst calculation from bandwidth with upload / download capacity 1024 kbps (1 Mbps) and application of simple queue configuration. A careful calculation and understanding technique must be performed if the burst will be applied to properly calculate the burst-threshold, the burst run, data-rate, average data-rate, burst-limit, max-limit and bandwidth available on the network, can be optimally managed.

Estimation of the parameters of token-buckets in multi-hop environments

Bandwidth verification in shaping scenarios receives much attention of both operators and clients because of its impact on Quality of Service (QoS). As a result, measuring shapers’ parameters, namely the Committed Information Rate (CIR), Peak Information Rate (PIR) and Maximum Burst Size (MBS), is a relevant issue when it comes to assess QoS. In this paper, we present a novel algorithm, TBCheck, which serves to accurately measure such parameters with minimal intrusiveness. These measurements are the cornerstone for the validation of Service Level Agreements (SLA) with multiple shaping elements along an end-to-end path. As a further outcome of this measurement method, we define a formal taxonomy of multi-hop shaping scenarios. A thorough performance evaluation covering the latter taxonomy shows the advantages of TBCheck compared to other tools in the state of the art, yielding more accurate results even in the presence of cross-traffic. Additionally, our findings show that MBS estimation is unfeasible when the link load is high, regardless the measurement technique, because the token-bucket will always be empty. Consequently, we propose an estimation policy which maximizes the accuracy by measuring CIR during busy hours and PIR and MBS during off-peak hours.