Average Error Probability Research Articles

Joint Packet Generation and Covert Communication in Delay-Intolerant Status Update Systems

In this letter, we jointly investigate packet generation and covert communication in delay-intolerant status update systems. For the first time, we establish a bridge between the prior transmission probability and the finite block-length in covert communication by modeling the stochastic status packet generation as a Poisson process. Considering a general prior transmission probability model, we derive closed-form expressions for the covertness constraint, the average packet error probability, and the effective covert throughput (ECT) to reveal the non-trivial tradeoff between the communication covertness and reliability. An optimization problem to maximize ECT is also formulated, and then the optimal transmit power and block-length are obtained, respectively. In contrast to exiting results, our examination shows that the longest block-length and the widely adopted equal prior probabilities are generally suboptimal when jointly considering the packet generation and covert communication.

An Opportunistic Power Control Scheme for Mitigating User Location Tracking Attacks in Cellular Networks

Cellular networks have been successfully evolved over the decades. Especially, Long-Term Evolution (LTE) has been exceedingly successful and the security threats against LTE systems have increased rapidly. Particularly, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tracking</i> LTE user devices has been shown to be effective as the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">temporary</i> user identifiers (IDs) are easily extracted and used to locate targeted devices by passive eavesdroppers. We notice that naive approaches, such as frequent updates of temporary user IDs, are <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">insufficient</i> to mitigate user-tracking attacks since the new and old temporary IDs for the same user device are easily <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">linkable</i> by adversaries who can measure the wireless channel characteristics between the user device and herself. In this paper, we propose an opportunistic uplink power control scheme to minimize the probability of successful user tracking by an adversary whose location is unknown. We devise the notion of average inference error probability in order to measure the level of users’ location privacy. Moreover, we derive the closed-form expression of the approximated average inference error probability and formulate an optimization problem to maximize the average inference error probability under a constraint of an allowable power budget for each user. Against a passive adversary, our proposed power control scheme effectively degrades an adversary’s inference ability by 50% when 10 users are scheduled in each transmission time slot, which will lead to almost 100% inference error at the adversary over multiple time slots.

Rotated Golden Codewords Based Space-Time Line Code Systems

The space-time line code (STLC) has been recently proposed in the literature. In STLC systems, the channel state information is assumed to be known at the transmitter, but not at the receiver. In the conventional STLC systems, the inputs of the STLC encoder are either M-ary phase shift keying symbols or M-ary quadrature amplitude modulation symbols and can achieve diversity order with very low detection complexity. In order to further improve the error performance of the STLC systems, in this paper, rotated Golden codewords based STLC (RGC-STLC) systems are proposed.We extend the 1&#x00D7;2 and 2 &#x00D7; 2 transmit-receive antenna structure in the conventional STLC into 1 &#x00D7; 4 and 2 &#x00D7; 4 transmit-receive antenna structures in the proposed RGC-STLC system. The inputs of the proposed RGC-STLC encoder are the rotated Golden codewords. Compared to the conventional 1 &#x00D7; 2 and 2 &#x00D7; 2 STLC systems, the 1 &#x00D7; 4 and 2 &#x00D7; 4 RGC-STLC systems achieve a higher diversity order. Based on the feature of the rotated Golden codewords, low complexity detection schemes for the 1 &#x00D7; 4 and 2 &#x00D7; 4 RGC-STLC systems are further proposed. Finally, the union bounds on the average symbol error probability for the 1 &#x00D7; 4 and 2 &#x00D7; 4 RGC-STLC systems are derived and shown to match the simulation results very well at high signal-to-noise ratios.

Intelligent Reflecting Surface-Aided URLLC in a Factory Automation Scenario

Different from conventional wired line connections, industrial control through wireless transmission is widely regarded as a promising solution due to its reduced cost, increased long-term reliability, and enhanced reliability. However, mission-critical applications impose stringent quality of service (QoS) requirements that entail ultra-reliability low-latency communications (URLLC). The primary feature of URLLC is that the blocklength of channel codes is short, and the conventional Shannon&#x2019;s Capacity is not applicable. In this paper, we consider the URLLC in a factory automation (FA) scenario. Due to densely deployed equipment in FA, wireless signal are easily blocked by the obstacles. To address this issue, we propose to deploy intelligent reflecting surface (IRS) to create an alternative transmission link, which can enhance the transmission reliability. In this paper, we focus on the performance analysis for IRS-aided URLLC-enabled communications in a FA scenario. Both the average data rate (ADR) and the average decoding error probability (ADEP) are derived under finite channel blocklength for seven cases: 1) Rayleigh fading channel; 2) With direct channel link; 3) Nakagami-m fading channel; 4) Imperfect phase alignment; 5) Multiple-IRS case; 6) Rician fading channel; 7) Correlated channels. Extensive numerical results are provided to verify the accuracy of our derived results.

Extended α-η-μ Fading Distribution: Statistical Properties and Applications

In this paper, the impact of the non-linearity of the propagation medium on the extended η-μ fading distribution is studied. In particular, the extended α-η-μ fading model in which the parameter α represents the non-linearity of the propagation environment is presented via providing the exact and asymptotic of the statistical properties, namely, the probability density function (PDF), cumulative distribution function (CDF), and generalized-moment generating function (G-MGF). To this effect, exact closed-form mathematically tractable expressions of the outage probability (OP), average symbol error probability (ASEP), amount of fading (AoF), channel quality estimation index (CQEI) and effective rate (ER) are obtained. The asymptotic behaviour at high average signal-to-noise (SNR) values is also analysed to gain further insights into the influence of the index α on the performance metrics of the wireless communication systems. Moreover, the average channel capacity (ACC) under different adaptive transmission techniques, such as, optimum rate and adaptation (ORA), capacity of the channel with inversion and fixed rate (CIFR), and truncated inversion and fixed rate (TIFR) are derived. The validation of the derived expressions is verified via comparing the numerical results with the Monte-Carlo simulations as well as some previous works for different scenarios.

Quantum Multiple Hypothesis Testing Based on a Sequential Discarding Scheme

We consider the quantum multiple hypothesis testing problem, focusing on the case of hypothesis represented by pure states. A sequential adaptive algorithm is derived and analyzed first. This strategy exhibits a decay rate in the error probability with respect to the expected value of measurements greater than the optimal decay rate of the fixed-length methods. A more elaborated scheme is developed next, by serially concatenating multiple implementations of the first scheme. In this case each stage considers as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a priori</i> hypothesis probability the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a posteriori</i> probability of the previous stage. We show that, by means of a fixed number of concatenations, the expected value of measurements to be performed decreases considerably. We also analyze one strategy based on an asymptotically large concatenation of the initial scheme, demonstrating that the expected number of measurements in this case is upper bounded by a constant, even in the case of zero average error probability. A lower bound for the expected number of measurements in the zero error probability setting is also derived.

A Hybrid Multi-Domain Index Modulation for Covert Communication

In this letter, a hybrid multi-domain index modulation scheme based on spreading codes domain and beam domain is proposed. In our design, the information bit stream is divided into two parts: one for covert transmission using the index of spreading code and the other using the directional modulation to improve bit error ratio (BER) performance in the desired direction and to prevent eavesdropping. Then, based on joint boundaries and statistical theory, the average error probabilities of legitimate users and eavesdroppers are derived. Moreover, we analyze the average BER and validate through simulation results that the proposed hybrid multi-domain scheme is capable of achieving better BER performance compared to conventional coded wireless communication systems.

A secure encryption method of communication channel based on cloud computing technology

The traditional channel encryption method is interfered by noise signal, which leads to long encryption time and poor security. This paper proposes a communication channel security encryption method based on cloud computing technology. In order to obtain the minimum benefits of the same channel and orthogonal channel in the frequency conversion receiver, the dual input and dual output model is constructed; the influence of time domain and frequency domain on the transmission signal is analyzed, and the nonlinear transmission characteristics of the channel signal are obtained. Through cloud computing technology, the channel transmission characteristics are divided into dynamic parameters and static parameters to realize the key distribution of communication channel under cloud computing technology; the balance factor is used to provide the key for the sorted generators to realize the secure encryption of communication channel. The results show that the average error probability of the proposed method is about 0.275, and the signal-to-noise ratio is between 115 and 118 SNR.

Hybrid MPPM-BB84 Quantum Key Distribution Over FSO Channel Considering Atmospheric Turbulence and Pointing Errors

Nowadays, a high level of security is required for the transmission of critical information. Quantum Key Distribution (QKD) systems are considered the best option to protect such information. Many studies have shown the efficiency of the QKD optical fiber inspired by M-ary pulse position modulation (MPPM). Free-Space Optical (FSO) links provide an efficient and effective data transmission system. However, cumulative effects of laser beam divergence, misalignment, and turbulence-induced fading on the received irradiance in the FSO link might allow an external eavesdropper located near the authorized receiver to break the transmission under certain conditions. This paper introduces the development of an FSO system based on the MPPM and the BB84 protocol (MPPM-BB84) over the Gamma-Gamma (GG) turbulence channel with pointing errors. Time Binning is implemented using MPPM to increase system security and reduce the quantum bit error rate (QBER). The system security is investigated under photon number splitting attack and excess noise. Closed-form expressions for asymptotic expressions of the average symbol error probability (SER), raw key rate (RKR), and secret key rate (SKR) are introduced. Moreover, the Monte-Carlo simulations are then used to prove the validity of the analytical results. The optimal values for the average photon number per pulse (to achieve the maximum RKR and SKR) for each symbol length can guarantee the stability of the FSO system under different weather conditions. Smaller symbol lengths are more tolerant of detector loss. The proposed system supports linking distances from 1 km to 3 km while keeping the SKR almost constant.

An Alternative Statistical Characterization of TWDP Fading Model.

Two-wave with diffuse power (TWDP) is one of the most promising models for the description of small-scale fading effects in 5G networks, which employs mmWave band, and in wireless sensor networks deployed in different cavity environments. However, its current statistical characterization has several fundamental issues. Primarily, conventional TWDP parameterization is not in accordance with the model’s underlying physical mechanisms. In addition, available TWDP expressions for PDF, CDF, and MGF are given either in integral or approximate forms, or as mathematically untractable closed-form expressions. Consequently, the existing TWDP statistical characterization does not allow accurate evaluation of system performance in all fading conditions for most modulation and diversity techniques. In this regard, physically justified TWDP parameterization is proposed and used for further calculations. Additionally, exact infinite-series PDF and CDF are introduced. Based on these expressions, the exact MGF of the SNR is derived in a form suitable for mathematical manipulations. The applicability of the proposed MGF for derivation of the exact average symbol error probability (ASEP) is demonstrated with the example of M-ary PSK modulation. The derived M-ary PSK ASEP expression is further simplified for large SNR values in order to obtain a closed-form asymptotic ASEP, which is shown to be applicable for SNR > 20 dB. All proposed expressions are verified by Monte Carlo simulation in a variety of TWDP fading conditions.

Joint computation and power allocation for NOMA enabled MEC networks in the finite blocklength regime

This paper investigates the reliable computation offloading in non-orthogonal multiple access enabled mobile edge computing networks, where the short-packet technique is adopted to meet the stringent latency requirements of delay-sensitive computing services. To characterize the reliability of computation offloading with finite blocklength coding, a novel analytical framework is developed to approximate the average overall block error probability (AOBEP) by using a double-case linearization. With the derived approximate expression for AOBEP, the joint optimization of computation workload and transmit power is further investigated, in order to minimize the AOBEP under the computation/communication delay constraints. To tackle the non-convexity of the formulated problem, the formulated problem is first decomposed into the computation workload problem and the transmit power allocation problem. For the computing workload problem, a closed-form solution is derived. Then, by applying the derived workload allocation, the power allocation is transformed into the convex form through some approximations and solved by the successive convex approximation technique. Finally, simulation results are provided to demonstrate the reliability enhancement of computation offloading and reveal the relationship between the workload/power allocation and the communication/computation delay.

Fast generalized threshold‐based signal detection for multiuser downlink NOMA systems with arbitrary power allocation

SummaryNon‐orthogonal multiple access (NOMA) is a technique to improve spectral efficiency. Based on the constellation relationship (CR) between the superposition‐coded signal and individual user's signals, in the literature, a simple detection scheme threshold‐based signal detection has been proposed for the two‐user downlink NOMA (DL‐NOMA) system with specific power allocations, not arbitrary power allocation. Furthermore, the average symbol error probability (ASEP) with squared M‐ary quadrature amplitude modulation for two‐user DL‐NOMA systems has also been derived based on this CR. Based on the threshold‐based signal detection for the two‐user DL‐NOMA systems with specific power allocation, in this paper, a generalized threshold‐based signal detection is proposed for all users in the multiuser DL‐NOMA systems with arbitrary power allocation, and then a fast generalized threshold‐based signal detection is further proposed. The generalized ASEP for each individual user in the multiuser DL‐NOMA system is further derived in Rayleigh fading channels. Both theoretical ASEP and simulated symbol error rate results validate the fast generalized threshold‐based signal detection scheme and the generalized ASEP for multiuser DL‐NOMA systems with arbitrary power allocations.

BER analysis of dynamic FOV based MIMO-NOMA-VLC system

Visible Light Communication (VLC) has evolved as a breakthrough technology for beyond 5G networks by providing a wide license-free spectrum. In this paper, we build a robust NOMA-VLC Network which exploits the MIMO technique. In particular, a two-user 2 × 2 MIMO-NOMA-VLC system is proposed which considers on–off keying (OOK) modulation and L-pulse position modulation (L-PPM). The closed-form bit-error-rate (BER) expressions for the OOK and L-PPM modulated two-user MIMO based NOMA-VLC system are derived with the consideration of perfect and imperfect successive interference cancellation (SIC). The analysis shows that the proposed system marginally outperforms the single-input single-output SISO-NOMA-VLC system. The error performance of L-PPM modulated system is superior to that of OOK modulated system for L>2. Further, the increment in the number of photo detector (PD’s) at the receiver does not improve the error performance of the system significantly. To address this, two dynamic field of view (FOV) strategies are proposed for attaining the additional enhancement in error performance of OOK and L-PPM modulated MIMO-NOMA-VLC system. The 2 × 2 MIMO-NOMA-VLC system based on dynamic FOV strategy-2 completely outperforms the 2 × 2 MIMO-NOMA-VLC systems based on static FOV and strategy-1 in terms of error performance. The effect of power allocation co-efficient, α, on the error performance of the proposed systems is investigated. The best average error probability of a two-user MIMO-NOMA-VLC system is attained at α = 0.3. The simulation results are in close alignment with those of the analytical outcomes.

Average Rate and Error Probability Analysis in Short Packet Communications Over RIS-Aided URLLC Systems

In this paper, the average achievable rate and error probability of a reconfigurable intelligent surface (RIS) aided systems is investigated for the finite blocklength (FBL) regime. The performance loss due to the presence of phase errors arising from limited quantization levels as well as hardware impairments at the RIS elements is also discussed. First, the composite channel containing the direct path plus the product of reflected channels through the RIS is characterized. Then, the distribution of the received signal-to-noise ratio (SNR) is matched to a Gamma random variable whose parameters depend on the total number of RIS elements, phase errors and the channels' path loss. Next, by considering the FBL regime, the achievable rate expression and error probability are identified and the corresponding average rate and average error probability are elaborated based on the proposed SNR distribution. Furthermore, the impact of the presence of phase error due to either limited quantization levels or hardware impairments on the average rate and error probability is discussed. The numerical results show that Monte Carlo simulations conform to matched Gamma distribution to received SNR for sufficiently large number of RIS elements. In addition, the system reliability indicated by the tightness of the SNR distribution increases when RIS is leveraged particularly when only the reflected channel exists. This highlights the advantages of RIS-aided communications for ultra-reliable and low-latency systems. The difference between Shannon capacity and achievable rate in FBL regime is also discussed. Additionally, the required number of RIS elements to achieve a desired error probability in the FBL regime will be significantly reduced when the phase shifts are performed without error.

Sparse Code Multiple Access Over Universal Filtered Multicarrier

In this paper, the uplink sparse code multiple access over universal filtered multicarrier (SCMA-UFMC) is studied. In SCMA-UFMC, each sub-band of UFMC is occupied by multiple users through SCMA. Note that the even-component of frequency domain (FD) received signal suffers from neither inter-sub-band interference nor inter-sub-carrier interference while the odd-component suffers from both. The message passing algorithm (MPA) is first employed to perform multiuser detection by utilizing only the even-component. Next, to improve the performance, the odd-component is further utilized. In this improvement, reliable estimates obtained by MPA over even-component are reconstructed and cancelled from odd-component, and then only a very small number of most-unreliable user data are refined by maximum likelihood method. Moreover, the union bound of the average symbol error probability (ASEP) of maximum likelihood detection using only even-component is derived, from which it is shown that ASEP is sub-band-independent. Finally, simulation results are given to demonstrate the performance of the proposed scheme and the effectiveness of the analytical ASEP result.

Analytical bounds for dynamic multichannel discrimination

The ability to precisely discriminate multiple quantum channels is fundamental to achieving quantum enhancements in data-readout, target detection, pattern recognition, and more. Optimal discrimination protocols often rely on entanglement shared between an incident probe and a protected idler-mode. While these protocols can be highly advantageous over classical ones, the storage of idler-modes is extremely challenging in practice. In this work, we investigate idler-free block protocols based on the use of multipartite entangled probe states. In particular, we focus on a class of idler-free protocol which uses nondisjoint distributions of multipartite probe states irradiated over multichannels, known as dynamic discrimination protocols. We derive analytical bounds for the average error probability of such protocols in a bosonic Gaussian channel setting, revealing idler-free strategies that display performance close to idler-assistance for powerful, near-term quantum sensing applications.

Comments on "tight bounds and invertible average error probability expressions over composite fading channels"

In the paper Tight Bounds and Invertible Average Error Probability Expressions over Composite Fading Channels of Wang et al. [1], they derived the algebraic formulas of upper- and lower-bounds for the average symbol error probability (ASEP) of M-ary phase shift keying (M-PSK) in a class of composite fading channels by using mixture gamma (MG) distribution, which is based on the assumption of the lack of closed-form expression for exact ASEP. However, the exact ASEP can be represented in closed-form by utilizing hypergeometric functions. Therefore, in this paper, we formulate the closed-form formulas of the exact and asymptotic ASEPs for general M-PSK in a class of the composite fading channels over MG distribution. We present some numerical results to validate our derived analytical results.

Mobile User Trajectory Tracking for IRS Enabled Wireless Networks

In this paper, we consider an intelligent reflecting surface (IRS) enabled mobile network, where a fixed access point (AP) communicates with a mobile user (MU) via the aid of an IRS. We assume that the MU moves from one elementary square to another following a Markov random walk within a grid, and propose a maximum a posteriori (MAP) criterion to track the movement of the MU by leveraging the line-of-sight component of the IRS-MU link. Since it is infeasible to derive an explicit expression for the average probability of estimation error (APEE) for the proposed MAP criterion, we derive a closed-form upper bound for the APEE, which is used as the cost function to optimize the phase shifts of the IRS units. Considering the unit modulus constraints incurred by the IRS units, a manifold optimization (MO) method is firstly employed to gain a favorable solution to the formulated optimization problem, followed by a low-complexity codebook based solution to circumvent the high computational cost of the MO method. Our numerical results demonstrate the superior performance of the proposed IRS phase shift designs over the benchmark method.

Counter-Intuitive Characteristics of Rational Decision-Making Using Biased Inputs in Information Networks

We consider an information network comprised of nodes that are: rational-information-consumers (RICs) and/or biased-information-providers (BIPs). Making the reasonable abstraction that any external event is reported as an answer to a logical statement, we model each node's information-sharing behavior as a binary channel. For various reasons, malicious or otherwise, BIPs might share incorrect reports of the event regardless of their private beliefs. In doing so, a BIP might favor one of the two outcomes, exhibiting intentional or unintentional bias (e.g. human cognitive biases). Inspired by the limitations of humans and low-memory devices in information networks, we previously investigated a graph-blind rational-information-consumer interested in identifying the ground truth. We concluded that to minimize its error probability, graph-blind RIC follows a counter-intuitive but tractable rule. In this work, we build on this foundational knowledge: “graph-blind RICs prefer the combination of information-providers that are all fully-biased against the a-priori likely input, over all other combinations.” Upon studying RICs with partial knowledge of the network graph, we find that they act similar to graph-blind RICs when their BIPs “listen to” sufficiently many information-providers of their own. Furthermore, if a common node is informing/influencing all n BIPs of a partially-aware RIC, that RIC anticipates its discovery of the “influential node” to diminish the average error probability by a factor that increases exponentially with n. However, from the partially-aware RIC's perspective, choosing n fully-, similarly-biased BIPs outweighs the discovery of influential nodes among its BIPs' sources. These insights might inform the design of consumer-centric information networks.

Performance analysis of angular diversity receiver based MIMO–VLC system for imperfect CSI

Visible light communication (VLC) has emerged as a promising technology for 5G and beyond communication networks in the last few years. In this paper, a multiple-input multiple-output (MIMO) VLC system using angular diversity receiver is proposed. In particular, the repetition coding is adopted at the transmitter and receiver diversity schemes, i.e. maximum-ratio combining (MRC), equal gain combining (EGC) and selection best combining (SBC), are adopted at the receiver for further performance enhancement. The closed-form expressions for average error probability of the proposed system are derived in the presence of imperfect channel state information (CSI). This research investigates that the increment in SNR is not sufficient to offset the effect of channel estimation error especially at high estimation error. The error performance analysis of the proposed MIMO–VLC system with and without estimation error is presented for different receiver locations and semi-half angles of the transmitting light emitting diodes (LEDs). Analytical results are verified with the simulation results.