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We explore perfect and quasi-perfect codes for the Bosonic channel, where information is generated by a laser and conveyed in the form of coherent states. In particular, we consider the phase-modulation codebook for coherent states in a Bosonic channel. We show that these phase-modulation codes are quasi-perfect as long as the cardinality of the code is the same as the dimension of the coherent states. These codes feature the smallest error probability among all codes of the same cardinality and the same dimension of the channel Hilbert space. We study the performance of these codes in terms of error probability, incorporating the degradation caused by a depolarizing or an erasure quantum channel. This work was supported in part by the MCIN/AEI/ 10.13039/501100011033 under Grant PID2019-104958RB-C41 and Grant RED2018-102668-T, in part by the Departament de Recerca i Universitats de la Generalitat de Catalunya 10.13039/501100002809 under Grant 2017 SGR 578 and Grant QuantumCAT 001-P-001644, and in part by the European Regional Development Funds (ERDF) .

We study a variation of Bayesian M-ary hypothesis testing in which the test outputs a list of L candidates out of the M possible upon processing the observation. We study the minimum error probability of list hypothesis testing, where an error is defined as the event where the true hypothesis is not in the list output by the test. We derive two exact expressions of the minimum probability or error. The first is expressed as the error probability of a certain non-Bayesian binary hypothesis test, and is reminiscent of the meta-converse bound. The second, is expressed as the tail probability of the likelihood ratio between the two distributions involved in the aforementioned non-Bayesian binary hypothesis test., Comment: 11 pages, submitted to Information and Inference: a journal of the IMA

The non-orthogonal coexistence between the enhanced mobile broadband (eMBB) and the ultra-reliable low-latency communication (URLLC) in the downlink of a multi-cell massive MIMO system is rigorously analyzed in this work. We provide a unified information-theoretic framework blending an infinite-blocklength analysis of the eMBB spectral efficiency (SE) in the ergodic regime with a finite-blocklength analysis of the URLLC error probability relying on the use of mismatched decoding, and of the so-called saddlepoint approximation. Puncturing (PUNC) and superposition coding (SPC) are considered as alternative downlink coexistence strategies to deal with the inter-service interference, under the assumption of only statistical channel state information (CSI) knowledge at the users. eMBB and URLLC performances are then evaluated over different precoding techniques and power control schemes, by accounting for imperfect CSI knowledge at the base stations, pilot-based estimation overhead, pilot contamination, spatially correlated channels, the structure of the radio frame, and the characteristics of the URLLC activation pattern. Simulation results reveal that SPC is, in many operating regimes, superior to PUNC in providing higher SE for the eMBB yet achieving the target reliability for the URLLC with high probability. Moreover, PUNC might cause eMBB service outage in presence of high URLLC traffic loads. However, PUNC turns to be necessary to preserve the URLLC performance in scenarios where the multi-user interference cannot be satisfactorily alleviated., Comment: Journal paper submitted for possible publication

With the recent explosion in the number of wireless communication technologies, the frequency spectrum has become a scarce resource. The need of the hour is an efficient method to utilize the existing spectrum and Cognitive Radio is one such technology that can mitigate the spectrum scarcity. In a cognitive radio system, the unlicensed secondary user accesses the spectrum allotted to licensed primary users when it lies vacant. To implement dynamic or opportunistic access of spectrum, secondary users perform spectrum sensing, which is a quintessential part of a Cognitive radio. From the Cognitive user’s point of view, lesser error probability means an increased likelihood of channel reuse when it is vacant, and a higher detection probability signifies better protection to the licensed users. In both cases the decision threshold plays a pivotal role in determining the fate of the unused spectrum. In this paper, we study the difficulty of selecting an appropriate threshold to minimize the error probability in an uncertain low SNR regime. The sensing failure issue is analyzed, and an optimal threshold is computed that yields minimum error rate. An adaptive double threshold concept has been proposed to make the detection robust and a closed-form equation for optimal threshold has been derived to minimize the error. The novel findings through simulation results exhibit improvement in Probability of detection and reduction in probability of error at low SNR in the presence of noise uncertainty factor.

We treat the problem of power and rate adaptation for a point-to-point ultra-reliable low latency communication (URLLC) system over parallel fading channels. The model includes a stochastic traffic arrival process and the transmissions are conducted in the finite blocklength (FBL) regime. The problem is formulated as a long term total power minimization problem under reliability, latency, and peak power constraints. We first establish a proactive outdated data dropping queueing model and transform the reliability constraint into a queuing status constraint. Then we train a deep reinforcement learning (DRL) agent to employ Deep Deterministic Policy Gradient (DDPG) in order to allocate the transmit power on each sub-channel and control the decoding error probability to meet the URLLC constraints. Simulation results show that the proposed DDPG-based algorithm can reduce the transmit power consumption by 13%-26% compared to a baseline approach based on effective capacity. Furthermore, the trained network is scalable and robust towards different traffic arrival models, as well as variations of the average arrival rate.

This work proposes a novel strategy for social learning by introducing the critical feature of adaptation . In social learning, several distributed agents update continually their belief about a phenomenon of interest through: $i$ ) direct observation of streaming data that they gather locally ; and $ii$ ) diffusion of their beliefs through local cooperation with their neighbors. Traditional social learning implementations are known to learn well the underlying hypothesis (which means that the belief of every individual agent peaks at the true hypothesis), achieving steady improvement in the learning accuracy under stationary conditions. However, these algorithms do not perform well under nonstationary conditions commonly encountered in online learning, exhibiting a significant inertia to track drifts in the streaming data. In order to address this gap, we propose an Adaptive Social Learning (ASL) strategy, which relies on a small step-size parameter to tune the adaptation degree. First, we provide a detailed characterization of the learning performance by means of a steady-state analysis. Focusing on the small step-size regime, we establish that the ASL strategy achieves consistent learning under standard global identifiability assumptions. We derive reliable Gaussian approximations for the probability of error (i.e., of choosing a wrong hypothesis) at each individual agent. We carry out a large deviations analysis revealing the universal behavior of adaptive social learning: the error probabilities decrease exponentially fast with the inverse of the step-size, and we characterize the resulting exponential learning rate. Second, we characterize the adaptation performance by means of a detailed transient analysis, which allows us to obtain useful analytical formulas relating the adaptation time to the step-size. The revealed dependence of the adaptation time and the error probabilities on the step-size highlights the fundamental trade-off between adaptation and learning emerging in adaptive social learning.

We study hypothesis testing problems with fixed compression mappings and with user-dependent compression mappings to decide whether or not an observation sequence is related to one of the users in a database, which contains compressed versions of previously enrolled users' data. We first provide the optimal characterization of the exponent of the probability of the second type of error for the fixed compression mappings scenario when the number of users in the database grows exponentially. We then establish operational equivalence relations between the Wyner-Ahlswede-Korner network, the single-user hypothesis testing problem, the multi-user hypothesis testing problem with user-dependent compression mappings and the identification systems with user-dependent compression mappings. These equivalence relations imply the strong converse and exponentially strong converse for the multi-user hypothesis testing and the identification systems both with user-dependent compression mappings. Finally they also show how an identification scheme can be turned into a multi-user hypothesis testing scheme with an explicit transfer of rate and error probability conditions and vice versa. QC 20210621

Serial concatenation of LDPC codes and continuous phase modulation (CPM) has recently gained significant attention due to its capacity-approaching performance, efficient detection as well as owing to its constant-envelope nature. Most of the previous contributions on LDPC coded CPM were devoted to the design of LDPC codes and their asymptotic performance analysis. However, there is a paucity of work on the finite-length performance estimation of LDPC coded CPM, primarily because existing performance estimation techniques cannot be readily applied to the LDPC coded CPM. To fill this gap, we conceive an analytical bit error probability estimation technique for finite-length LDPC coded CPM in the waterfall region. Numerical results are provided both for regular and irregular LDPC codes having different codeword lengths, demonstrating that the estimated performances are closely matched by the simulated ones.

In molecular communication (MC), the motion of information molecules in the medium is usually described by the Brownian motion and governed by the Fick’s laws. However, there are some potential scenarios of MC where the kinetics of information molecules is non-Fickian. In this letter, we investigate one of this kind of MC. The manner of information molecules in the channel is subdiffusion. A three-dimensional MC system with a spherical absorbing receiver is considered. The subdiffusion channel is analyzed. The closed-form expressions of the first hitting probability and its peak time are given. Furthermore, we investigate the performance of MC by timing and amplitude modulation schemes in a subdiffusion channel. The error probability for both modulation schemes is analyzed.

Free space optical (FSO) communication has emerged to provide line of sight connectivity and higher throughput over unlicensed optical spectrums. Cognitive radio (CR), on the other hand, can utilize the radio frequency (RF) spectrum and allow a secondary user (SU) to share the same spectrum with the primary user (PU) as long as the SU does not impose interference on the PU. Owing to the potential of these emerging technologies, to provide full spectrum efficiency, this paper focuses on the mixed CR RF-FSO transmission scheme, where RF communication is employed at one hop followed by the FSO transmission on the other hop in a dual-hop decode-and-forward (DF) configuration. To quantify the performance of the proposed scheme, closed form error probability is derived over Rayleigh/Exponentiated Weibull (EW) fading distributions by considering the statistical and instantaneous feedback channel of the primary network. We also employed an asymptotic analysis to illustrate the diversity gain of the overall system. We believe that the proposed scheme can be applicable to the 5G+ networks where an unlicensed university student connects to the home computer with the aid of an FSO path.

In this paper, we aim to develop an analytical framework for design and analysis of new generation mobile networks fronthaul/backhaul links based on the application of free-space optical (FSO) technology. Taking the receiver hardware imperfections into account, we present an efficient analytical approach in analyzing average symbol error probability (SEP) of the coherent FSO system employing M-ary phase-shift keying (PSK). Optical signal transmission is influenced by pointing errors and atmospheric turbulence. The signal intensity fluctuations caused by atmospheric turbulence are modeled by general Málaga (M) distribution, which takes into account the effect of multiple scattered components. We estimate the range of the signal-to-noise ratio at which the SEP floor appears, as well as the value of this non-removable error floor. The results illustrate that the effect of imperfect phase error compensation on the SEP is more critical under weaker turbulence conditions and for higher order modulation formats. Based on the analytical tools presented here, it is possible to estimate tolerable value of standard deviation of phase noise for the given value of SEP. This value of standard deviation is an important parameter in designing the phase-locked loop filter in the receiver.

International audience; In this paper, we consider a molecular communication system that is made of a 3D unboundeddiffusion channel model without flow, a point transmitter, and a spherical absorbing receiver. In particular,we study the impact of inter-symbol interference and analyze the performance of different threshold-basedreceiver schemes. The aim of this paper is to analyze and optimize the receivers by using the conventionalmodel-based approach, which relies on an accurate model of the system, and the emerging data-drivenapproach, which, on the other hand, does not need any apriori information about the system model andexploits deep learning tools. We develop a general analytical framework for analyzing the performanceof threshold-based receiver schemes, which are suitable to optimize the detection threshold. In addition,we show that data-driven receiver designs yield the same performance as receivers that have perfectknowledge of the underlaying channel model.

Privacy security issues under the classic randomized response (RR) model proposed by Warner and its extended $K$ -RR model are studied. First, in order to provide references for the accuracy of the private distribution estimation problem under RR mechanism, the lower bounds of the differential privacy parameter and the number of participates are deduced for an accuracy objective of $({\alpha }, {\delta })$ – accurate in statistics. Second, when the prior distribution is nonuniform, the data utility has a ceiling effect in the high privacy region by taking the prior into account. In this case, the average distortion, which is defined as the expected Hamming distance between the input and output data, is no longer feasible to measure the data utility. Motivated by this, the error probability is proposed as a measure of data utility for unifying different privacy metrics, where the error probability is defined to be the expected Hamming distance between the input and reconstructed data based on maximum a posteriori estimation. Third, under a unified privacy-preserving framework using RR mechanism based on error probability criterion, the relationship among differential privacy, identifiability privacy, and mutual information privacy is established. Given a maximum allowable error probability $P_{E}^{\mathrm {max}}$ , the optimal privacy parameters of these three privacy notions are derived with the full consideration of the prior distribution. Then, a Bayes-based utility function, which corresponds to the converse of the Bayes risk, is constructed to measure the degree of privacy leakage. Given a maximum allowable correct probability $P_{C}^{\mathrm {max}}$ , the accuracy objective of the statistical estimate is considered to derive the range of local differential privacy parameter from the perspective of security. Fourth, all the research results above are further extended to $K$ -RR mechanism too. Finally, the correctness and effectiveness are further verified by simulation experiments. The results reveal that the error probability can be applied to any prior distribution case, while the average distortion criterion is only a special case with uniform distribution. Therefore, the error probability proposed in the paper is more reasonable to be used as a common criterion to measure the data utility for the RR model so as to unify different privacy metrics.

In this paper, we propose a methodology to design chaos-based communication systems, which exploits the topological structure of 3-D chaotic attractors. The first step consists in defining a proper partition of a Poincaré section of the attractor and the subsequent encoding of the chaotic trajectories. Then, the evolution mechanism of the chaotic attractor, according to the dynamical restrictions imposed by the chaotic flow, is represented by a state diagram, where each state represents a region of the Poincaré section or a branch in the template of the chaotic attractor. The state transitions are associated with segments of chaotic trajectories that connect the corresponding regions of the Poincaré section. The chaotic signals are transmitted over both additive white Gaussian noise and Rayleigh flat fading channels, and a trellis structure derived from the state diagram is used at the decoder to estimate the transmitted information sequence. Finally, the bit error rate performance of the system is analyzed.

This paper proposes M-ary circular θ-quadrature amplitude modulation (CTQAM) for M = 2l, l ≥ 4, which is constructed by rearrangement of the signal points based on θ-QAM. We provide a construction method for the signal constellation of CTQAM and analyze the symbol and bit error performances of M-ary CTQAM in additive white Gaussian noise (AWGN) and Nakagami-m fading channels. Through computer simulations, we validate theoretical results.

We derive a single-letter upper bound to the mismatched-decoding capacity for discrete memoryless channels. The bound is expressed as the mutual information of a transformation of the channel, such that a maximum-likelihood decoding error on the translated channel implies a mismatched-decoding error in the original channel. In particular, it is shown that if the rate exceeds the upper-bound, the probability of error tends to one exponentially when the block-length tends to infinity. We also show that the underlying optimization problem is a convex-concave problem and that an efficient iterative algorithm converges to the optimal solution. In addition, we show that, unlike achievable rates in the literature, the multiletter version of the bound cannot not improve. A number of examples are discussed throughout the paper. This work was supported in part by the European Research Council under Grant 725411 and in part by the Spanish Ministry of Economy and Competitiveness under Grant TEC2016-78434- C3-1-R.

In this paper, we investigate the adversarial robustness of hypothesis testing rules. In the considered model, after a sample is generated, it will be modified by an adversary before being observed by the decision maker. The decision maker needs to decide the underlying hypothesis that generates the sample from the adversarially-modified data. We formulate this problem as a minimax hypothesis testing problem, in which the goal of the adversary is to design attack strategy to maximize the error probability while the decision maker aims to design decision rules so as to minimize the error probability. We consider both hypothesis-aware case, in which the attacker knows the true underlying hypothesis, and hypothesis-unaware case, in which the attacker does not know the true underlying hypothesis. We solve this minimax problem and characterize the corresponding optimal strategies for both cases.

28th Signal Processing and Communications Applications Conference, SIU 2020 -- 5 October 2020 through 7 October 2020 -- -- 166413 In this work, error performance of dual-branch single-input multiple-output (SIMO) systems is analyzed over -u fading channels. An analytical expression is derived by using Chernoff approximation for the error probability of the considered system. Then, an asymptotic error expression is also proposed for the considered system. The results obtained from the derived expression are presented in comparison with exact results. Numerical results are shown for different configurations in order to analyze the effects of different values of fading parameter, antenna number and modulation type. In conclusion, it is observed that the approximate results are close to the exact results. © 2020 IEEE. 2-s2.0-85097582829

This work studies the deviations of the error exponent of the constant composition code ensemble around its expectation, known as the error exponent of the typical random code (TRC). In particular, it is shown that the probability of randomly drawing a codebook whose error exponent is smaller than the TRC exponent is exponentially small; upper and lower bounds for this exponent are given, which coincide in some cases. In addition, the probability of randomly drawing a codebook whose error exponent is larger than the TRC exponent is shown to be double-exponentially small; upper and lower bounds to the double-exponential exponent are given. The results suggest that codebooks whose error exponent is larger than the error exponent of the TRC are extremely rare. The key ingredient in the proofs is a new large deviations result of type class enumerators with dependent variables. The research of R. Tamir and N. Merhav was supported by Israel Science Foundation (ISF) grant no. 137/18. The research of N. Weinberger was partially supported by the MIT–Technion fellowship, and the Viterbi scholarship, Technion. The research of A. Guillen i F ´ abregas was funded in part by the European Research Council under ERC grant 725411 and by the Spanish Ministry of Economy and Competitiveness under grant TEC2016-78434-C3-1-R. This paper was presented in part at the 2019 IEEE International Symposium on Information Theory, Paris, France, 7-12 July, 2019.

This paper proposes an efficient simulation method based on importance sampling to estimate the random-coding error probability of coded modulation. The technique is valid for complex-valued modulations over Gaussian channels, channels with memory, and naturally extends to fading channels. The simulation method is built on two nested importance samplers to respectively estimate the pairwise error probability and generate the channel input and output. The effect of the respective number of samples on the overall bias and variance of the estimate of the error probability is characterized. For a memoryless channel, the estimator is shown to be consistent and with a small variance, growing with the square root of the code length, rather than the exponential growth of a standard Monte Carlo estimator. This work has been funded in part by the European Research Council under ERC grant agreement 725411, and by the Spanish Ministry of Economy and Competitiveness under grant TEC2016-78434-C3-1-R.

We consider nonadaptive group testing with Bernoulli tests, where each item is placed in each test independently with some fixed probability. We give a tight threshold on the maximum number of tests required to find the defective set under optimal Bernoulli testing. Achievability is given by a result of Scarlett and Cevher; here we give a converse bound showing that this result is best possible. Our new converse requires three parts: a typicality bound generalising the trivial counting bound, a converse on the COMP algorithm of Chan et al, and a bound on the SSS algorithm similar to that given by Aldridge, Baldassini, and Johnson. Our result has a number of important corollaries, in particular that, in denser cases, Bernoulli nonadaptive group testing is strictly worse than the best adaptive strategies., Comment: 7 pages, 1 figure

Single-photon avalanche diode (SPAD) has recently been introduced as a powerful detector for long-distance underwater visible light communication (UVLC). In this paper, the performance of the SPAD detector in UVLC is analyzed considering the effect of the turbulence-induced fading resulting from air bubbles in addition to the combined effect of attenuation and scattering. An automatic repeat request (ARQ) system is adopted to mitigate different underwater impairments and reduce the error probability at the receiver side. Approximate packet error rate (PER) expressions are derived using Laguerre Gauss polynomial for a finite number of transmission. Next, the average energy efficiency and throughput are analyzed to account for the increased energy consumption cost and the decreased effective transmission rate, which results from adopting the ARQ scheme. Finally, different numerical results are introduced to verify the derived PER expressions, demonstrate the ability of the proposed ARQ system in extending the transmission range, and show the tradeoff between energy efficiency and throughput.

International audience; We consider the performance analysis of reconfigurable antenna-aided space shift keying (RectAnt-SSK) system for Internet-of-Things applications. In particular, we propose a mathematical framework for analyzing performance of RectAnt-SSK in a general context using a single RecAnt (equipped with several ideal radiation patterns (RPs)) and multiple receive antennas. We take into account the effect of RPs from RecAnt in conjunction with a ray tracing based two dimensional (2D) channel model. The effectiveness of the proposed framework is then assessed through Monte Carlo simulation using simulated RPs.

Safety-related communication system SRComS uses a safety code for achieving the integrity of messages transferred between safety-related devices. In most cases, it is a block systematic code that uses syndromic decoding technique. The authors discuss the possibilities of using the convolutional structures for safety-related applications requiring creation of safety case based on quantitative assessment in relation to the transmission integrity level. This assessment is based on code analysis focused mainly on the error probability calculation. The results published in the practical part are obtained using a model created in Matlab environment, in which the chosen convolutional structures were tested. These tests were focused on the transmission error probability analysis provided by a binary symmetric channel, and also on optimization of other parameters affecting the residual error in the decoding algorithm. The results are generalized into concept of methodology for the convolutional codes safety assessment in compliance with standards for safety-related applications.

This paper studies the operation of multi-agent networks engaged in multi-task decision problems under the paradigm of simultaneous learning and adaptation. Two scenarios are considered: one in which a decision must be taken among multiple states of nature that are known but can vary over time and space, and another in which there exists a known "normal" state of nature and the task is to detect unpredictable and unknown deviations from it. In both cases the network learns from the past and adapts to changes in real time in a multi-task scenario with different clusters of agents addressing different decision problems. The system design takes care of challenging situations with clusters of complicated structure, and the performance assessment is conducted by computer simulations. A theoretical analysis is developed to obtain a statistical characterization of the agents' status at steady-state, under the simplifying assumption that clustering is made without errors. This provides approximate bounds for the steady-state decision performance of the agents. Insights are provided for deriving accurate performance prediction by exploiting the derived theoretical results.

We propose a saddlepoint approximation of the error probability of a binary hypothesis test between two i.i.d. distributions. The approximation is accurate, simple to compute, and yields a unified analysis in different asymptotic regimes. The proposed formulation is used to efficiently compute the meta-converse lower bound for moderate block-lengths in several cases of interest. This work has been funded in part by the European Research Council (ERC) under grants 714161 and 725411, by the Spanish Ministry of Economy and Competitiveness under grants TEC2013-41718-R, RYC-201416332, IJCI-2015-27020 and TEC2016-78434-C3 (AEI/FEDER, EU), by the Madrid Autonomous Community under grant S2103/ICE-2845 and by the Spanish Ministry of Education, Culture and Sport under grant FPU14/01274.

In this letter, we first of all propose for a parallel wireless sensor network (WSN) a decoding technique that well exploits the correlation knowledge of the sensing data to be transmitted from each sensor to the fusion center (FC). This letter then derives an algorithm to estimate the observation error probabilities, representing the correlation, of the links between the sensing object and sensors. The convergence of the algorithm is also evaluated. Furthermore, the comparison of bit-error-rate (BER) performance between two cases, one uses estimated observation error probabilities, the other assumes the full knowledge of the observation error probabilities, is made. The simulation results show that the difference is only around 0.3 - 0.5 dB in per-link signal-to-noise power ratio (SNR), depending on the number of sensors.

International audience; In this paper, we study the Symbol Error Probability (SEP) performance of a hybrid/integrated satellite-terrestrial cooperative network. In particular, we focus on the case of mobile relays that forward the satellite signal to a masked mobile destination node. The Selective Decode-and-Forward (SDF) transmission scheme is implemented and only the relay nodes which can successfully decode the satellite message are selected to retransmit the signal. The destination node exploits the spatial diversity advantages by implementing a typical Maximum Ratio Combining (MRC) technique. The closed-form expressions for the exact average SEP of the arbitrary M-ary phase shift keying and M-ary quadrature amplitude modulation signaling with MRC diversity reception over independent but not necessarily identically distributed fading channels are derived using a Moment Generating Function (MGF) approach. These closed-form expressions are represented in terms of a finite sum of Lauricella hypergeometric functions. The analytical expressions show excellent agreement with the simulation results. Numerical results show that for a system using QPSK under the frequent heavy shadowed fading condition, the diversity gain of approximately 7 dB can be obtained at the SEP of 10^{-1} with respect to the direct transmission, when only one relay is used. It increases to around 12 dB in the case of 3 relays.

Two alternative exact characterizations of the minimum error probability of Bayesian M-ary hypothesis testing are derived. The first expression corresponds to the error probability of an induced binary hypothesis test and implies the tightness of the meta-converse bound by Polyanskiy et al.; the second expression is a function of an information-spectrum measure and implies the tightness of a generalized Verdú-Han lower bound. The formulas characterize the minimum error probability of several problems in information theory and help to identify the steps where existing converse bounds are loose. This work was supported in part by the European Research Council under Grant 259663, in part by the Spanish Ministry of Economy and Competitiveness under Grant FPDI-2013-18602, Grant RYC-2011-08150, and Grant TEC2012-38800-C03-03, and in part by the European Union’s 7th Framework Programme under Grant 303633 and Grant 329837.

We propose a methodology for designing the local mapping rule for fully synchronized but energy-limited sensors in a distributed detection system, where sensors communicate with the fusion center over multiaccess channels. Using the proposed methodology, we come up with the modified detect-and-forward scheme and the modified amplify-and-forward scheme. The performance of the two schemes is analyzed. We show that optimizing the local mapping rule can lead to a larger error exponent under total power constraint. Refereed/Peer-reviewed

With the increasing proliferation of different communication devices sharing the same spectrum, it is critical to understand the impact of interference in heterogeneous wireless networks. In this paper, we put forth a mathematical model for coexistence in networks composed of both narrowband (NB) and ultrawideband (UWB) wireless nodes, based on fundamental tools from stochastic geometry. Our model considers that the interferers are spatially scattered according to a Poisson field, and are operating asynchronously in a wireless environment. We first determine the statistical distribution of the aggregate interference for both cases of NB and UWB emitters. We then provide error probability expressions for two dual configurations: 1) a NB victim link subject to the aggregate UWB interference, and 2) a UWB victim link subject to the aggregate NB interference. The results show that while the impact of a single interferer on a link is often negligible due to restrictions on the transmitted power, the aggregate effect of multiple interferers may cause significant degradation. Therefore, aggregate interference must be considered to ensure coexistence in heterogeneous networks. The proposed analytical framework shows good agreement with physical-level simulations of the system.

GMSK (Gaussian Minimum Shift Keying) y DBPSK (Differential Binary Phase Shift Keying) son dos esquemas de modulación digital usados frecuentemente en los sistemas de comunicaciones vía radio; sin embargo, existe interdependencia en el aprovechamiento de sus beneficios (eficiencia espectral, baja tasa de error de bit, baja interferencia intersímbolos, etc.); es decir, la optimización de un parámetro acarrea problemas en otro; por ejemplo, el esquema GMSK logra reducir el ancho de banda al introducirle un filtro gaussiano a un modulador MSK (Minimum Shift keying) a cambio de incrementar la interferencia intersímbolos en el sistema. Por su parte, el esquema DBPSK obtiene menor probabilidad de error, ocupando mayor ancho de banda; así mismo, facilita la transmisión de los datos de forma síncrona debido al retardo de un bit que tiene el receptor al recuperar la señal. Gaussian minimum shift keying (GMSK) and differential binary phase shift keying (DBPSK) are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc). Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift keying) modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error probability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when recovering a signal.

This letter presents a simple closed-form expression to evaluate the error probability of binary fully-interleaved fading channels. The proposed expression does not require a numerical Laplace transform inversion, numerical integration or similar techniques, and captures the role of the relevant system parameters in the overall error performance. The expression has the same asymptotic behavior as the Bhattacharyya (Chernoff)-union bound but closes the gap with the simulation results. Its precision is numerically validated for coded and uncoded transmission over generic Nakagami-m fading channels.

The proceeding at: 2015, IEEE International Conference on Communications (ICC) took place 8-12 June in London (UK) A non-coherent detection assisted Differential Phase Shift Keying aided large-scale MIMO system is designed in a wireless uplink where multiple single-antenna users are transmitting to the base station's receiver equipped with a very large number of receive antennas. We show that the signal to interference plus noise ratio (SINR) scales with the number of receive antennas, which confirms the same scaling law found in coherent systems. We propose a range of constellation designs that allow us to separate the users' signals at the receiver by relying only on the knowledge of the average received power per user. We analyse the error probability and provide insights into the beneficial selection of the constellation parameters. Finally, we provide some numerical results showing that our proposals require a lower number of receive antennas to achieve a given error probability than other non-coherent benchmark schemes available in the literature, while they are not far from an equivalent coherent system relying on realistic channel estimation settings. This work was supported by projects CSD2008-00010, TEC2011-29006-C03-03 and by a mobility grant of Spanish Ministry of Education. The financial support of the UK Government’s Engineering & Physical Sciences Research Council (EPSRC) as well as that of the Research Councils UK (RCUK) and of the European Research Council’s Senior Research Fellow Grant is also gratefully acknowledged.

Udgivelsesdato: October We present an Extended Quadratic Frobenius Primality Test (EQFT), which is related to an extends the Miller-Rabin test and the Quadratic Frobenius test (QFT) by Grantham. EQFT takes time about equivalent to 2 Miller-Rabin tests, but has much smaller error probability, namely 256/331776t for t iterations of the test in the worst case. We give bounds on the average-case behaviour of the test: consider the algorithm that repeatedly chooses random odd k bit numbers, subjects them to t iterations of our test and outputs the first one found that passes all tests. We obtain numeric upper bounds for the error probability of this algorithm as well as a general closed expression bounding the error. For instance, it is at most 2-143 for k = 500, t = 2. Compared to earlier similar results for the Miller-Rabin test, the results indicates that our test in the average case has the effect of 9 Miller-Rabin tests, while only taking time equivalent to about 2 such tests. We also give bounds for the error in case a prime is sought by incremental search from a random starting point.

Author(s): Koyuncu, E; Jafarkhani, H | Abstract: We study a multiple-input single-output fading channel, where we would like to minimize the channel outage probability or symbol error rate (SER) by employing beamforming via quantized channel state information at the transmitter (CSIT). We consider a variable-length limited feedback scheme where the quantized CSIT is acquired through feedback binary codewords of possibly different lengths. We design and analyze the performance of the associated variable-length quantizers (VLQs) and compare their performance with the previously studied fixed-length quantizers (FLQs). For the outage probability performance measure, we construct VLQs that can achieve the full-CSIT performance with finite rate. Moreover, as the signal-to-noise ratio P tends to infinity, we show that VLQs can achieve the full-CSIT outage probability performance with asymptotically zero feedback rate. For the SER performance measure, we show that while the SER with full-CSIT is not achievable at any finite feedback rate, the diversity and array gains with full-CSIT can be achieved using VLQs with asymptotically zero feedback rate as P → ∞ . Our results show that VLQs can significantly improve upon the traditional FLQs that require infinite feedback rate to achieve the outage probability or the diversity and array gains with full-CSIT.

The aim of this paper is the determining the system performance in detecting the QPSK signal. The error probability is determined when the signal, Gaussian noise, pulse interference and imperfect carrier phase recovery are taken into consideration. Phase locked loop, as the constituent part of the receiver, is used in providing the synchronization reference signal extraction, which is assumed to be imperfect. The obtained results are based on the PLL non-linear model of the first order, with the emphasis on the degradation in the system performance produced by the imperfect carrier signal extraction. The system performance is determined when the signal corrupted by pulse interference and Gaussian noise is applied at the input of the receiver.

In this paper, the noise-enhanced detection problem is investigated for the binary hypothesis-testing. The optimal additive noise is determined according to a criterion proposed by DeGroot and Schervish (2011), which aims to minimize the weighted sum of type I and II error probabilities under constraints on type I and II error probabilities. Based on a generic composite hypothesis-testing formulation, the optimal additive noise is obtained. The sufficient conditions are also deduced to verify whether the usage of the additive noise can or cannot improve the detectability of a given detector. In addition, some additional results are obtained according to the specificity of the binary hypothesis-testing, and an algorithm is developed for finding the corresponding optimal noise. Finally, numerical examples are given to verify the theoretical results and proofs of the main theorems are presented in the Appendix.

This paper studies the random-coding exponent of joint source-channel coding for a scheme where source messages are assigned to disjoint subsets (referred to as classes), and codewords are independently generated according to a distribution that depends on the class index of the source message. For discrete memoryless systems, two optimally chosen classes and product distributions are found to be sufficient to attain the sphere-packing exponent in those cases where it is tight., Comment: Submitted to IEEE Transactions on Information Theory

Cataloged from PDF version of article. An M-ary communication system is considered in which the transmitter and the receiver are connected via multiple additive (possibly non-Gaussian) noise channels, any one of which can be utilized for the transmission of a given symbol. Contrary to deterministic signaling (i.e., employing a fixed constellation), a stochastic signaling approach is adopted by treating the signal values transmitted for each information symbol over each channel as random variables. In particular, the joint optimization of the channel switching (i.e., time sharing among different channels) strategy, stochastic signals, and decision rules at the receiver is performed in order to minimize the average probability of error under an average transmit power constraint. It is proved that the solution to this problem involves either one of the following: (i) deterministic signaling over a single channel, (ii) randomizing (time sharing) between two different signal constellations over a single channel, or (iii) switching (time sharing) between two channels with deterministic signaling over each channel. For all cases, the optimal strategies are shown to employ corresponding maximum a posteriori probability (MAP) decision rules at the receiver. In addition, sufficient conditions are derived in order to specify whether the proposed strategy can or cannot improve the error performance over the conventional approach, in which a single channel is employed with deterministic signaling at the average power limit. Finally, numerical examples are presented to illustrate the theoretical results. © 2013 Elsevier Inc.

Nonlinear stochastic differential equations are used to model a version of the changepoint problem. State estimates of the minimum mean-square-error-type are used in likelihood-ratio tests to detect the time of change. System performance is evaluated by deriving theoretical expressions for the false alarm probability and a special case of the miss error probability. The approach uses a Fokker-Planck equation. 44 8 1628 1632

SUMMARY This paper deals with the problem of recovering the input signal applied to a linear time-invariant system from the measurements of its output and the a priori knowledge of the input statistics (blind equalization). Under the assumption of an i.i.d. non-Gaussian input sequence a new iterative procedure based on phase-sensitive high-order cumulants for adjusting the coeƒcients of a transversal equalizer is introduced. The main feature of the proposed technique is the automatic selection of the equalization delay so as to improve the equalization performance. A method for the a posteriori evaluation of the obtained accuracy in PAM systems is also introduced. It consists of the computation of an upper bound on the probability of error depending on certain moments of the equalizer output and the statistics of the channel input and therefore can be used in a blind equalization context. Based on the result of such a computation, it can be decided whether it is necessary to consider a longer equalization filter in the iterative procedure. ( 1997 by John Wiley & Sons, Ltd.

This paper presents a comprehensive approach to the smart application of redundancy techniques in multiple-layer hierarchical systems. Computing systems today are rapidly evolving into increasingly complex structures with an ever-increasing number of components. Moreover, future technology generations are expected to have associated lower levels of quality. For these reasons, it is emerging nowadays a renewed interest in the development of reliable architectures. In this work we delve into this topic putting special emphasis on the system hardware hierarchy. We analyze the advantages in terms of reliability of distributing redundancy effort in cross-layer systems. We base our analysis on a general fault model that takes into account both devices and interconnections. Using the Rent's Law we relate the number of devices and interconnections for different configurations of redundancy and compare the global error probability. Our results provide meaningful information about the benefits that can be achieved by properly choosing the system layer at which to apply redundancy, and if applicable, the optimal distribution of redundancy effort through the system layers. © 2013 IEEE.

In this work, we propose a new approach of deriving the bounds between entropy and error from a joint distribution through an optimization means. The specific case study is given on binary classifications. Two basic types of classification errors are investigated, namely, the Bayesian and non-Bayesian errors. The consideration of non-Bayesian errors is due to the facts that most classifiers result in non-Bayesian solutions. For both types of errors, we derive the closed-form relations between each bound and error components. When Fano’s lower bound in a diagram of “Error Probability vs. Conditional Entropy” is realized based on the approach, its interpretations are enlarged by including non-Bayesian errors and the two situations along with independent properties of the variables. A new upper bound for the Bayesian error is derived with respect to the minimum prior probability, which is generally tighter than Kovalevskij’s upper bound.

Binary message-passing (BMP) decoders for rootlow- density parity-check (LDPC) codes over block fading channels (BFC) are studied using density evolution (DE) and outage boundary analysis. A-priori channel estimation techniques suitable for root-LDPC code are proposed based on DE. The results show that BMP decoders can achieve full diversity performance if soft decisions from the channel are available. Refereed/Peer-reviewed

Due to copyright restrictions, the access to the full text of this article is only available via subscription. In this paper, we investigate the effect of channel estimation error on the error rate performance of a multi-relay system with amplify-and-forward relaying. We consider orthogonal relaying and study both conventional cooperative systems (i.e., all relays participate in the relaying phase) and opportunistic cooperative systems (i.e., only the best relay participates in the relaying phase). Based on the derivation of effective signal-to-noise ratio at the receiver taking into account channel estimation error, we obtain closed-form expressions for bit error rate. Monte-Carlo simulations are further provided to confirm the analytical results.

Due to copyright restrictions, the access to the full text of this article is only available via subscription. In this paper, we investigate the performance of a cooperative network with adaptive decode-and-forward (DF) relaying over time-selective frequency-flat Rayleigh fading channels. In adaptive DF relaying, only a subset of the available relays with "good" channels are allowed to participate in the relaying phase. The destination combines the direct and the relayed signals using maximal ratio combining technique. Pilot-symbol-assisted modulation (PSAM) is used for the estimation of time-varying fading channel coefficients. For the system under consideration, we derive an exact closed-form expression for the average bit error rate. Such closed form solutions are highly desirable because they allow for rapid and efficient evaluation of system performance. We further present computer simulations to validate our analytical results.

Due to copyright restrictions, the access to the full text of this article is only available via subscription. In this paper, we examine the effect of channel estimation error on the error and outage probabilities of a multi-relay system with amplify-and-forward relaying over frequency-flat Rician fading channel. We consider orthogonal relaying and study both conventional cooperative systems (i.e., all relays participate in the relaying phase) and opportunistic cooperative systems (i.e., only the best relay participates in the relaying phase). Based on the derivation of effective signal-to-ratio (SNR) at the receiver taking into account channel estimation error, we obtain closed-form expressions for error and outage probabilities in high SNR regime. Such closed form solutions are highly desirable because they allow for rapid and efficient evaluation of system performance. Computer simulations are used to validate our analytical results.

This paper investigates the effects of non-ideal channel state information in adaptive M-ary quadrature amplitude modulation systems with subset diversity. The slow adaptive modulation (SAM) technique, which adapts the modulation parameters to slow channel variations, is considered. With respects to fixed scheme modulation systems, SAM achieves a good gain in terms of spectral efficiency (SE) and outage probability and, compared to fast adaptive modulation, reduces the system complexity by lowering the feedback rate. Resources dedicated to channel estimation affect both the system performance, in terms of error and outage probability, and the effective SE for which a proper definition is needed. Here, we evaluate the performance of SAM technique when pilot-assisted channel estimation errors are considered. Taking into account the number of pilot symbols transmitted, an effective SE is obtained to address the tradeoff between channel estimation quality and SE.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009, Bu tez çalışmasında, röleli ve işbirlikli iletişim yöntemleri ile FSK/PSK modülasyonu kullanılarak verici anten çeşitlemesi sağlanmıştır. Rölenin veya diğer kullanıcıların alınan bilgiyi çözerek tekrar alıcıya ilettikleri çöz ve aktar yöntemini kullandıkları varsayılmıştır. Çalışmada özel olarak 2FSK/4PSK modülasyonu kullanılarak, röleli ve işbirlikli çeşitlemeli sistemlere ilişkin hata başarımlarının bilgisayar benzetimleri ile analizi yapılmıştır. Hem Rayleigh hem de Nakagami-m sönümlemeli kanallar için analizler yapılmıştır. Benzetimler değişken röle sayılarına ve kaynak ile röle arasındaki kanalın kazanç değerlerine göre yapılmıştır. Çalışmada tek ve çok röleli sistemler için hem kodlamalı hem de kodlamasız yapılar incelenirken, iki kullanıcılı işbirlikli sistemlerde kodlamalı işbirliği tekniği kullanılmıştır. Tez çalışması sonucunda röleli ve işbirlikli sistemlerde 2FSK/4PSK modülasyonu kullanarak 8PSK modülasyonuna göre daha iyi sonuçlar elde edilebildiği gösterilmiştir., In this study, transmitter antenna diversity is ensured by using FSK/PSK modulation with relaying and cooperative transmit methods. The decode and forward method in which the relays or the other users decode the signal transmited by the source and then transmit to the destination, is assumed. Computer simulations of relaying and cooperative systems have been done and analyzed by using 2FSK/4PSK modulation technique. Both, Rayleigh and Nakagami-m fading channels have been used in transmission. Simulations have been made by variable relay numbers and channel gains between source and relays. While uncoded and encoded structures for one and multi-relaying systems have been analysed, coded cooperative diversity techniques have been used for the cooperative systems with two users. As a result of this thesis, it is observed that relaying and cooperative systems using 2 FSK/4PSK modulation achive better error performance than the systems using 8PSK., Yüksek Lisans, M.Sc.