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The multi-connectivity is a key enabler for ultra-reliable low-latency communications. To evaluate its performance and suitability to various use casessystem-level studies are essential, where the physical layer (PHY) plays an important role. Therefore, PHY modeling is required which is time-intensive and requires highly complex computations. For this purpose, the PHY performance is usually abstracted in terms of signal-to-interference-plus-noise ratio (SINR), also known as physical layer abstraction (PLA). However, due to fading, the symbols inside a packet could have different SINRs which require effective SINR mapping to compute an equivalent SINR. In the context of multi-connectivity, the received SINR depends on all connected links where each link experiences independent fading and on the used link combining technique. As a result, the computation of effective SINR also depends on the combining technique and fading experienced by individual links. To model PHY performance by considering all these effects, we develop PLA for multi-connectivity communications. This includes the computation of received symbols SINR for various link combining techniques and mapping them to effective SINR using enhanced exponential effective SINR mapping (eEESM). Furthermore, a new optimization method is introduced for eEESM to reduce its optimization complexity. Simulation results show that the proposed PLA accurately estimate the performance of different order of multi-connectivity communications under various fading conditions.

Power packet dispatching system has been proposed for smart power management in the form of discretized packet. In this paper, we discuss the routing optimization of power packets on the network of power routers. We propose a cost metric for the power packet delivery by circuit analysis of the router network. Using the metric, we formulate the optimization problem as a general shortest path problem from a source node to a load node. The result of numerical simulations shows that the proposed algorithm can allocate distributed power sources to load demands and identify the optimal path for the power delivery., This paper was submitted to Nonlinear Theory and Its Applications, IEICE on May 21, 2021

Phase Modulation Orthogonal Frequency Division Multiplexing (PM-OFDM) and Code Division Multiple Access (CDMA) have distinctive advantages. On one hand, PM-OFDM is an attractive technique to combat multipath fading and reduce high PAPR in conventional OFDM. On the other hand, CDMA has the ability to serve multiple users at the same time and/or frequency. In this article, a new PM-OFDM-CDMA system that combines PM-OFDM and CDMA is proposed. The idea behind the proposed technique is to combine the advantages of these techniques in order to enhance the performance of the 5G system by serving multiple users simultaneously. The performance of the proposed system is analysed in terms of BER under different channel conditions. A Minimum Mean Square Equaliser (MMSE) scheme is used in order to avoid the effect of multipath effect and noise simultaneously. From the simulation results, we conclude that the proposed system has good performance that can improve 5G wireless communication networks, especially for battery-powered mobile devices. This amounts to the constant envelope of the proposed waveform which generates constant instantaneous power and therefore reduced PAPR.

Communications systems concerted over wireless channels depend on the environment. Communications system can be more reliable and efficient by properly analyzing wireless channels. Today's most important features are a high data rate and reliable performance to exploiting viable networks during this new information age. The channel is not time-invariant in wireless communication, so the received signal exhibits amplitude, phase, and angle variations due to multipath fading. Increasing data rates and reducing bandwidth make Orthogonal Frequency Division Multiplexing (OFDM) an important component of wireless communication systems. The OFDM technique uses many carriers very efficiently. With this scheme, interference is robustly reduced, and fading scenarios are easily accommodated. Analyzing digital modulation schemes requires evaluating link performance with fading channels. The paper compares channel performance over varying fading environments using a variety of modulation schemes. We study the BER and SNR properties of the AWGN, Rician fading and Rayleigh fading channels modulated with BPSK, QPSK, and M-ary QAM.

Orthogonal frequency division multiplexing (OFDM) is a popular multicarrier technique in communication system owing to its robustness against multipath fading and less complexity. Deep learning (DL...

Unslotted ALOHA protocol has been adopted as a channel access mechanism in commercial low-power wide-area networks (LPWANs), such as Sigfox and long-range (LoRa) alliance. This work examines the throughput and random access (RA) delay distribution of unslotted ALOHA systems by considering exponential random backoff (ERB) or uniform random backoff (URB) algorithm. We further characterize the operating region of the systems as unsaturated stable, bistable, and saturated regions in terms of the new packet arrival and retransmission rates. To run the system stably with the maximum throughput, we propose a Bayesian online backoff algorithm that estimates the number of backlogged devices. Its performance is compared with other algorithms, such as particle filter (PF)-based algorithm, binary exponential backoff (BEB) algorithm, and the algorithm of exploiting exact backlog size information. Through extensive simulations, it is demonstrated that the performance of the proposed algorithm is very close to the upper bound and robust to time-varying traffic condition.

The Internet is nowadays suffering dramatically serious attacks, with the distributed denial of service (DDoS) attacks being the representative and dominant ones. It is seen that, to stabilize the buffer queue length around a given target under DDoS attacks in the relevant routes is vitally important and helpful to mitigate the attacks and to improve the quality of service (QoS) for normal users. In the current paper, a stochastic queue dynamic model with L e ´ vy jump noise, which is affected by the continuous Brownian motion and the discontinuous Poisson process, is worked out to develop a novel and accurate mathematical framework for the stability of a route queue that deals with constant-rate DDoS attacks. This article proposes a security defensive mechanism in the network for solving the network collapse that can possibly be caused by DDoS attacks, otherwise. Particularly, based on the formulation of a stochastic queue dynamic with L e ´ vy jump noise, the mechanism that characterizes the behavior of the queue at routers is presented for stabilizing the queue length under constant-rate DDoS attacks. By applying the stochastic control theory into analyzing the performance of queue dynamic under constant-rate DDoS attacks, some explicit conditions are established under which the instantaneous queue length converges to any given target in a route. Simulation results demonstrate the satisfaction of the proposed defense mechanism with sharp contrast to the state of the art active queue management (AQM) schemes.

In this work, we leverage the clustered $\beta$ -Ginibre point process (GPP) and the queueing theory to analyse the delay performance in a large-scale repulsive fog radio access network (F-RAN) with computation offloading, which plays a key role on the delay performance. In particular, the average delay defined as the mean value of delay for executing the computing tasks and the task completion probability (TCP) defined as the probability of the delay for executing the computing task being smaller than a target delay, are derived in analytical forms and validated by Monte Carlo simulations. Based on these results, the optimal rate threshold, which affects the task offloading probability and the transmission delay, and the optimal cloud offloading probability to minimize the average delay and maximize the TCP are jointly analysed numerically. Moreover, an approximated result of the average delay is provided to reduce its computational complexity. The results show that the repulsion in the F-RAN significantly decreases the average delay and increases the TCP, but equipped with the optimal rate threshold and the cloud offloading probability, the effects of repulsion on the average delay and the TCP become trivial. Furthermore, with the optimal cloud offloading probability and rate threshold, the average delay and the TCP can be significantly reduced and improved in the hybrid processing mode compared with those in the local processing mode, respectively. The optimal rate thresholds lie in the range of 3 to 13 Mbps under our simulation environment, which can reduce a maximum of 60% of the average delay and increase a minimum of 0.17 of the TCP.

In this paper, we investigate the consensus problem for discrete linear multi-agent systems (MASs) with Markovian packet dropouts. Both identical and nonidentical packet dropouts are studied. For the discrete-time MASs under identical packet dropouts, we present the expectation of the total sojourn time of packet dropouts and successful message transmission, the switching number from packet dropouts to successful message transmission, and the awaken number of packet dropouts and successful message transmission. Based on these expectations, a linear consensus controller is designed through analyzing the transient properties of the Markov process such that the MASs can reach consensus almost surely for any initial distribution of packet dropouts. When it comes to the nonidentical packet dropouts where all the packets are independent and stochastic, a Markovian-lossy-channel based switching model (MLCBS model) is proposed. Based on the MLCBS model, we also propose an easy-to-implement linear consensus controller such that the MASs with nonidentical packet dropouts can achieve consensus almost surely. Finally, the theoretical results are illustrated by simulation examples.

In opportunistic networks, the nodes connect to each other wirelessly and use the store-carry-forward technique to transmit the data from one node to another node. The nodes in opportunistic networ...

Implementation of the cross-fade audio effect requires shaping the fade profile for a certain audio content that is to be faded out, as well as customizing the audio fade for an additional audio content, which is to be faded in, with the purpose of achieving a smooth transition between the two different audio contents. Similar to the case of applying adjustable fades, the audio cross-fades are usually carried out in the off-line mode, by employing various transcendental functions to shape the audio fades (both fade-out and fade-in effects). To improve the computational capabilities by minimizing the delay between receiving the position within the cross-fade effect and returning both the volume of the faded out section and the volume of the faded in one, we consider that, during the cross-fade effect, the audio volume of each of the two overlapping sections is the output of a rational function i.e. a mapping defined by a rational fraction. A plain HTML5/JavaScript implementation, prepared to be tested in any major browser, is advanced in the paper in order to highlight the suitability of the suggested approach to audio cross-fade customization with real-time computing.

Existing algorithms for identifying clients on a network segment are based on static client binding by MAC address. MAC address generation is based on pseudo-random sequences of 0–256 characters. W...

After perceiving the idle channels using spectrum sensing, the cognitive user (CU) accesses these channels using suitable medium access control (MAC) protocol where the decision on optimal spectrum sensing, transmission time, and proper coordination with other CUs are the key characteristics of the MAC protocol. In the conventional MAC protocol, the CUs exploit the common control channel for the spectrum sensing information exchange in order to negotiate the channel access. After the spectrum sensing, each CU contends for the access of idle channel using various spectrum access protocols. The system model and proposed hybrid self‐scheduling multichannel‐MAC (HSMC‐MAC) protocol are illustrated. The chapter consists of the performance analysis of proposed protocol for the perfect and imperfect spectrum sensing scenarios. It presents the simulation results for the perfect and imperfect spectrum sensing scenarios. An improved frame structure for the distributed cognitive radio networks is proposed in order to enhance the throughput by exploiting the spectrum efficiently.

In this paper, we conduct rate-distortion and outage probability analyses for Wyner-Ziv (WZ) systems, where the information sequences from a source and a helper are transmitted to the destination over block Rayleigh fading multiple access channels (MACs). This work has been motivated by decision-making systems, where the aim is to make right decisions based on the observations. Hence, the most critical performance metric is the accuracy of decisions, even allowing distortion in wireless transmission. A sufficient condition for the successful transmissions is that the WZ and MAC regions intersect. For the ease of calculating the outage probability, we propose an approximated, yet accurate, WZ rate region. The outage probabilities of the WZ systems are then evaluated both in orthogonal and MAC transmissions. It is shown that the transmission efficiency of the system with MAC is significantly improved compared to orthogonal transmission. Furthermore, a helper-selection scheme is introduced to further reduce the outage probability of the WZ-MAC systems. The results show that the outage probability decreases, of which decay corresponds to the $(L+1)$ -order diversity with $L$ helpers in small value range of the average signal-to-noise ratio (SNR), while it converges into $L$ as the average SNR becomes large.

Recent work demonstrates that IEEE 802.11 networks are vulnerable to cascading DoS attacks, wherein a single node can remotely and suddenly congest an entire network. In this paper, we propose, analyze, simulate, and experimentally verify a counter-measure against such attacks. Our main idea is to optimize the duration of packet transmissions in order to weaken coupling effects between neighboring pairs of nodes. Toward that end, we propose a new theoretical model that relates the utilization of neighboring pairs of nodes using a sequence of iterative equations. The model captures important specifications of the IEEE 802.11 MAC layer. Through a fixed point analysis of the sequence, we show how to optimally set the packet duration so that, on one hand, cascading DoS attacks are avoided and, on the other hand, throughput is maximized. We validate the analysis through extensive ns-3 simulations and demonstrate the effectiveness of the mitigation through experiments with real Wi-Fi cards. A key insight is that IEEE 802.11 networks with relatively large MAC overhead are less susceptible to cascading DoS attacks than networks with smaller MAC overhead.

Consider a multihop wireless network serving multiple flows in which wireless interference constraints between links are described by a link-interference graph. The timely-throughput of a flow is defined as the throughput of packets of that flow that reach their destination node within a specified deadline, and the weighted timely throughput of the network is their weighted average over the flows with a given set of positive weights. The problem is particularly challenging, and has generally been open, when there is wireless interference between transmissions. We show that a modified CSMA routing-scheduling policy with an appropriate set of attempt probabilities is nearly optimal for maximizing weighted timely-throughput. This policy has the useful property that the routing-scheduling decision for an individual packet is solely a function of its location and time-to-deadline, and so a wireless node does not require knowledge of the global network state. It is easily implementable in a decentralized fashion by the nodes given the attempt probabilities. A gradient-based adaptive CSMA routing-scheduling policy to determine the optimal attempt probabilities is further provided. It moves along the gradient of the timely throughput and converges to a local maximum.

Joint maximum likelihood (ML) multiuser detection for quasi-synchronous multicarrier code division multiple access (MC-CDMA) system has an excessive computational complexity, and it increases exponentially as the number of users and bits in each of the modulation symbols increases. Recently, sphere decoding (SD) has been adopted for multiuser detection whose complexity is polynomial in nature with the number of users, and it does not rely on the number of bits in the modulation. In this article, first we provide a construction of large size quasi-complementary sequence sets (QCSSs), and then a low-complexity optimum SD algorithm is proposed to detect the multiuser communication in QCSS-based MC-CDMA (QCSS-MC-CDMA) system. The complexity analysis has shown that the proposed SD-based QCSS-MC-CDMA receiver for multiuser communication provides lower complexity than that of ML-based QCSS-MC-CDMA receiver. We also show that peak to average power ratio of the proposed system is lesser than that of complete complementary code (CCC) based MC-CDMA (CCC-MC-CDMA) system. The proposed system overcomes the fractional delay problem which is noticed for CCC-MC-CDMA receiver. The bit error rate performance of the proposed SD-based QCSS-MC-CDMA system is compared with maximum ratio combining based MC-CDMA, ML-based MC-CDMA, frequency domain equalization based MC-CDMA, and CCC-MC-CDMA receivers over Rayleigh frequency selective fading channels. The work is validated through Monte Carlo simulation results.

Cooperative communication has occurred to be a promising technology for future wireless networks. Characterizing its performance, in terms of symbol error rate, outage probability, data rate, etc. over the generalized fading channels are essential to wholly attain its benefits. In this paper, the closed form expressions for the outage probability of the multi-relay cooperative communication using decode-and-forward protocol over generalized fading channels ( $$\eta-\mu$$ and $$\kappa-\mu$$ ) has been derived in terms of gamma function. Firstly, the outage probability for generalized $$\eta-\mu$$ and $$\kappa-\mu$$ fading channels are computed, followed by the outage probability expression for the overall system. The final expressions are in the form of infinite series which converges very rapidly and hence it is accurately approximated by considering finite number of terms in summation. Analytical results are plotted to demonstrate the the impact of various channel parameters. It is also shown that how the outage performance improves with the number of relays. The obtained outage probability expressions for generalized fading environment can be readily extended for any generalized system model.

This work proposes an average-case performance measurement as a meaningful and non-trivial way of evaluating and comparing queueing protocols on a multiple-access channel (MAC). We prove that Little’s Law holds for this way of measuring latency and number of packets in the system, also for adversarial packet arrival (which was not the case for the previously considered worst-case measurement), and analyze performance of popular MAC protocols. Interestingly, some of them have asymptotically the same average and worst case queue sizes, but not packet latencies, while others exhibit entirely opposite behavior. We also propose a consistent methodology for classifying queueing protocols, based on protocol features, such as synchronization, collision detection, queue-size awareness etc.

This paper study and present, power allocation strategy on sub-carriers of multiuser OFDM employed for orthogonal chaotic vector shift keying (MU OFDM-OCVSK) over multipath frequency selective fading channels. firstly, the MU OFDM-OCVSK system is modeled with power allocated on reference and information bearing subcarriers. Then, the computed bit error rate equation of the power allocation MU OFDM-OCVSK system is derived. The optimal power allocation strategy on subcarriers is obtained using convex optimization. Finally, compared with the traditional MU OFDM-DCSK and MU OFDM-OCVSK without power allocation system the proposed system can achieve an excellent BER performance under multipath Rayleigh fading channels. Numerical and Simulation results emphasize the remarkable features of the proposed optimal power allocation strategy.

In this {\color{red}{paper}} we discuss about the $ap-$Henstock-Kurzweil integrable functions on a topological vector spaces. Basic results of $ap-$Henstock-Kurzweil integrable functions are discussed here. We discuss the equivalence of the $ap-$Henstock-Kurzweil integral on a topological vector spaces and the vector valued $ap-$Henstock-Kurzweil integral. Finally, several convergence theorems are studied.

The IEEE 802.11 is the most dominating protocol in the wireless local area networks and in which, the fundamental mechanism to access the channel is called distributed coordination function (DCF). As this mechanism is random, the calculation of the performance metrics for IEEE 802.11 networks is focused on the determination of probabilities such as collision probability and successful transmission probability. Recently, there are performance studies in the literature are based on the mathematical models developed using the Markov chains, which model the DCF mechanism with fragmentation in IEEE 802.11 network under imperfect channel. Yet, these models suffer with high collision probability and low successful transmission probability and as a result, the transmission with fragmentation is not recommended at all in the IEEE 802.11 basic DCF networks when the bit error rate is low $$\left( {BER < 5 \times 10^{ - 5} } \right)$$ . In order to solve this, a new analytical model of the basic DCF mechanism with fragmentation is presented in this paper to accurately evaluate throughput metric in the lightly disturbed IEEE 802.11 network at $$BER = 10^{ - 5}$$ under saturated traffic. Analytical results show that our model significantly improves the throughput of the IEEE 802.11 DCF network compared with existing model and hence, provides a higher throughput than that is improved with the request to send/clear to send (RTS/CTS) mode, regardless to network size.

Recent advances in underwater networking exploit the large propagation delays in underwater channels to schedule transmissions which increase the performance of underwater acoustic sensor networks (UASNs). The underwater channel is broadcast in nature so it supports broadcast and multicast transmissions. In this paper, we discuss novel scheduling strategies, based on TDMA (Time Division Multiple Access), for UASNs where packets may be bound for multiple destinations. The main contributions are to establish an upper bound on the throughput of multicast networks, in which each packet has the same number of intended destinations, by exploiting large propagation delays, and explore network topologies that can achieve this bound. As an example, we study the throughput of unicast and multicast ring networks, including the properties of optimal, valid, perfect and fair transmission schedules. Further, several algorithms to find fair and optimal schedules for unicast and multicast ring networks are presented. Finally, we perform extensive simulations for uniform ring networks, as well as more general ring networks, in both noiseless and noisy underwater channels. Simulation results verify that the proposed algorithms can effectively determine the optimal schedules for ring networks, which achieve the maximum possible throughput and asymptotically approach the upper bound on the throughput of multicasting UASNs.

This letter proposes a new approach to the reliability analysis of IEEE 802.11 one-dimensional (1-D) broadcast mobile ad hoc networks. The approach finds a simple and effective way to derive the distribution of signal-to-interference-to-noise ratio (SINR) on each receiver, which is required for evaluation of the reliability metrics and the channel capacity. Having observed that the effective interference area depends on a given SINR threshold, the SINR distribution derivation is converted to estimating the SINR threshold related interference areas that are dynamically changed in a communication channel. The analysis is applied to two network configurations for example, and it is cross validated by the extensive simulations. Compared with the previous models, the new approach is more general, more precise, and faster.

The network sampling rate is important in the overhead transmission line monitoring system. A larger sampling rate can provide more available monitored data to be transmitted, which can effectively improve the response speed to emergency events of the overhead transmission line system. Considering the harsh environment of the overhead transmission line wireless network, quality‐of‐service (QoS) requirement becomes an important issue for multi‐hop transmission. Thus, in this paper, an end‐to‐end delay optimisation algorithm for string‐topology multi‐hop wireless network is proposed, by which the maximum packet arrival rate and the allowable maximum sampling rate of network can be obtained with desirable soft QoS guarantees. Based on the IEEE 802.11 standards and the basic probability theorem, a novel end‐to‐end delay performance analytical model is firstly proposed. Then, combined with the derived analytical model, an end‐to‐end delay optimisation algorithm by maximising the packet arrival rate is developed. Finally, a numerical study of a string‐topology multi‐hop network is presented to verify the effects of packet arrival rate, backoff contention window size, hop number, data packet size on the end‐to‐end delay performance.

Cognitive radio (CR) is a new intelligent wireless technology that aims at improving spectrum utilization by allowing opportunistic access to the underutilized licensed spectrum. Wireless CR operating environment is typically characterized by its unreliable and unpredictable channel conditions and time availability due to fading and the randomness of primary radio (PR) activities. In such environment, packet fragmentation is needed to enhance the probability of success/packet delivery and reduce the needed number of packet re-transmission attempts. Specifically, the quality and availability of the PR channels along with the data packet size should be considered when designing communication protocols for CR networks (CRNs) such that the packet success probability is improved. Based on the quality and availability of the PR channels, an optimal-packet size metric is derived, which is defined as the packet size that can be transmitted over a selected channel while guarantying a predefined probability of success. In this paper, we propose three fragmentation-based channel assignment algorithms: fixed-fragment size algorithm, first-fit algorithm and near-exact fit algorithm. The first algorithm divides the packet equally over the selected channels while the other algorithms use variable fragment size. The main objectives of the algorithms are to enhance network throughput, decrease the number of dropped packets and reduce the average number of retransmission attempts. This preserves more channels for potential future CR transmissions, resulting in higher network throughput with less energy consumption. Simulation results show that the proposed algorithms significantly outperform existing CRN channel assignment algorithms with no fragmentation.

A vehicular network underpinned by the 3-tier vehicle-edge-cloud infrastructure enables an efficient and safer travel experience. The compute-intensive vehicular applications are often offloaded to the edge and/or cloud servers to enhance the applications’ Quality of Services (QoS). The underlying edge-cloud servers consume a high among of energy. Consequently, it becomes crucial to optimizing energy consumption in the offloading process. Current energy-efficient offloading strategies in 2-tier vehicle-edge infrastructure, do not account for cloud computing energy consumption. In this paper, we address this void by proposing a machine learning-based energy-aware offloading algorithm, which optimizes the energy of the edge-cloud computing platform. The offloading strategy is enabled by the Support Vector Machine (SVM) regression model machine learning algorithm used for the edge-cloud power prediction. The experimental results show that the proposed algorithm is a promising approach in energy savings.

The impact of the traffic characteristics of secondary users (SUs) on the performance of cognitive radio networks (CRNs) should be understood for designing operation rules. This paper focuses on multi-type burst services and network congestion problem in CRNs and evaluates the QoS of SUs based on multiple cross-layer considerations. A two-state Markov-modulate Bernoulli process (MMBP-2) is adopted to model packet flows of SUs with different burst degrees in CRNs. We propose a two-dimensional discrete queuing model to consider spectrum access, burstiness of traffic, network congestion, channel environment, user activity and finite buffer. We construct an iterative algorithm to compute the steady-state distribution of the proposed queuing model and determine the performance metrics like the throughput, the average delay, the average queue length and the total packet loss probability. Numerical analysis evaluates the QoS of SUs under different burst environments.

In this paper, the least-squares channel estimation (LSCE) is investigated for Massive-Multiple-Input Multiple-Output (Ma-MIMO) OFDM systems based on pilot tones. The uplink (UL) transmission is considered, in which a channel estimation approach is proposed by forming a matrix equation with all the unknown channel parameters (UCPs) in one vector and estimating that vector by the least-square (LS). The mean square error (MSE) of the LSCE is computed. Flat fading and frequency-selective fading are evaluated for single and multiple OFDM symbols, concerning this MSE. The requirement of the pilot sequence is investigated in flat fading and frequency-selective fading. Besides, it is shown that the number of pilots exhibits desirable trade-offs between the base station (BS) antenna and channel taps. Rayleigh and Rician channel fading is considered to evaluate the system performance with different channel taps. Performances are compared in terms of Bit Error Rate (BER). Moreover, to enhance linear detector performance, nonlinear detectors are used. The requirement of pilot sequence and the increased receive diversity provide a lower BER for the nonlinear detector.

This paper discusses the distributed coordination function (DCF) access mechanism which is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme. Simulation projects for different DCF performance parameters have been built using the OPNET network simulator. The projects are mainly basic service set (BSS) topology simulated under different parameter values (data rate, fragmentation, RTS/CTS, number of nodes, and load condition). Simulation results show when the DCF access mechanism is better under what load condition, and how to choose the best fragmentation threshold and other access-mechanism specific parameters according to the network conditions. Simulation results were validated against a theoretically calculated maximum throughput (the simulation maximum throughput was about 70% of the theoretically calculated maximum throughput).

To effectively improve the throughput of the IEEE contention-based wireless local area network (WLAN) system, many uplink medium access control layer (MAC) protocols based on multi-user multiple-input multiple-output (MU-MIMO) technology have been proposed. However, a common problem of these approaches is that many physical layer (PHY) operations, e.g., synchronization, are not considered. As a result, existing methods may find difficulties in real-world implementation. In this article, we propose a simple yet practical uplink scheme for systems with multiple antennas. The main idea is to conduct multi-user beamforming (MU-BF) at an access point such that it can resolve collided signals from multiple competitive users; the proposed scheme can effectively reduce the upstream collision probability and improve system throughput. The other distinct advantage of the proposed scheme is that the MAC protocol of the original IEEE 802.11 standard, i.e., distributed coordination function (DCF), can remain unchanged. The mathematical analysis of system performance is also presented and verified. Simulations show that the proposed scheme significantly outperforms conventional WLAN systems.

Mobile edge computing can provide powerful computation services around the end-users. However, given the broadcast nature of wireless transmissions, offloading the computation tasks via the uplink channels would raise serious security concerns. This paper proposes an online approach to jointly optimize local processing, transmit power, and task offloading decisions without the a-priori knowledge of the dynamic environments. The proposed approach can guarantee the secure offloading and asymptotically minimize the time-average energy consumption of devices while maintaining the stability of the ergodic secrecy queues and task queues. By exploiting the Lyapunov optimization, the local processing, transmit power, and task offloading variables can be decoupled between time slots. The subproblems on local processing and computation offloading can be solved separately. Convex optimization and graph matching can be used to solve the computation offloading subproblem. Simulations show that the performances of the proposed approach are superior to other popular approaches.

Non-orthogonal multiple access (NOMA) can be efficiently used in land mobile satellite (LMS) communications in order to increase link availability, coverage and reliability. In this letter, we study -for first time in the literature- the outage performance of an uplink LMS system consisting of two terrestrial user nodes which perform NOMA in the uplink, with either successive interference cancellation or joint decoding at the satellite receiver. Closed-form expressions for the outage probability are derived for both cases assuming composite shadowed-Rician fading channels. Finally, numerical results and simulations validate the theoretical analysis.

This paper presents Zero-Day Attack Packet Highlighting System. Proposed system outputs zero-day attack packet information from flow extracted as result of regression inspection of packets stored in flow-based PCA. It also highlights raw data of the packet matched with rule. Also, we design communication protocols for sending and receiving data within proposed system. Purpose of the proposed system is to solve existing flow-based problems and provides users with raw data information of zero-day packets so that they can analyze raw data for the packets.

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This paper presents a highly compact dual-band elliptical wide-slot (EWS) antenna with high bandwidth dimension ratio (BDR) having one inverted L-slot for WLAN and WiMAX applications. Initially, th...

In this paper, the problems of time-delay, packet loss and quantisation for network control with global Lipschitz nonlinearity are investigated. The packet losses between the forward and backward c...

In this letter, we propose a downlink nonorthogonal multiple access network with hybrid long-packet communications (for a central user) and short-packet communications (for a cell-edge user). The outage probability of the central user and average block error rate (BLER) of the cell-edge user in flat Rayleigh fading channels are theoretically derived. Furthermore, we provide the asymptotic outage probability and average BLER when the signal-to-noise ratio (SNR) is high. Numerical results illustrate that both the analytical outage probability of the central user and the analytical average BLER of the cell-edge user match the simulation results.

Orthogonal frequency-division multiplexing (OFDM) is one of the most widely adopted modulation schemes because it offers several desirable features, such as spectral efficiency and low complexity implementation. Moreover, it is highly suitable for adaptive implementation. Nevertheless, OFDM does not have any special immunity against multipath fading as compared to single-carrier systems. Therefore, we propose in this article a new OFDM configuration, denoted as OFDM-smart (OFDM-S), where superposition modulation is used to introduce transmit diversity to reduce the bit error rate (BER) while maintaining the spectral efficiency and bit rate fixed. The proposed scheme is based on clustering specific subcarriers that can cooperate by sharing their transmission resources. The cooperation is performed such that all subcarriers transmit their data jointly using all the subcarriers within their cluster. The system performance is derived in terms of BER performance over Nakagami- $m$ frequency-selective fading channels where efficient expressions are presented in terms of a single finite integral, and closed-form expressions are derived for the asymptotic BER. The obtained analytical results corroborated by simulation show that the OFDM-S can provide substantial BER improvement over conventional OFDM, due to the transmit diversity.

In this paper, power allocation in cellular networks is proposed based on the outage probability and normalized signal to interference plus noise ratio (SINR). Upper and lower bounds on the outage probability are determined using the normalized SINR considering path loss, shadowing, and fading. The problems of minimizing the user power subject to outage probability and target SINR constraints are then considered as power allocation problems. These problems are solved using Perron-Frobenius theory and geometric programming (GP). The objectives are to efficiently provide users with flexible date rates and reduce the outage probability and user transmit power. Typically, only the path loss is considered in determining the outage probability whereas path loss, multipath fading and lognormal shadowing are considered in this paper along with the interference from other users. Results are presented which show that the proposed power allocation schemes provide better performance than the target SINR tracking power control (TPC), opportunistic power control (OPC), and temporary removal and feasibility check power control (DFC) algorithms.

To support wireless Internet of things (IoT) devices, this paper presents a new solution which combines wireless power transfer and mobile edge computing. Specifically, we consider one mobile device, which first harvests energy from radio frequency signals sent by a base station and then offloads all or part of its data to be processed to the base station. The process of energy harvesting and offloading span over multiple fading blocks. The target is to maximize the average amount of processed data in unit time. To achieve this target, we optimize the stopping rule for energy harvesting (i.e., when to stop energy harvesting and start offloading) and the number of fading blocks for data offloading. To solve the formulated problem optimally, we decompose it into two levels. In the lower level, the stopping rule for energy harvesting is optimized given a fixed number of fading blocks for offloading. The associated lower-level problem is solved optimally based on a series of special properties of the problem. In the upper level, the number of fading blocks for offloading is optimized. Efficiency of our work with fully offloading mode and partially offloading mode is shown by using simulation.

This paper studies iterative learning control (ILC) using faded measurements without system information. The measurements are transmitted through fading channels, where the fading phenomenon is mod...

Packet sets and inverse packet sets are two kinds of novel mathematical tools to analyze dynamic information systems. With advances in inverse packet sets, random inverse packet information is proposed by introducing random characteristics into inverse packet sets. Hence, random inverse packet information has dynamic and random characteristics, and is an extended form of inverse packet sets. Furthermore, random feature, dynamic feature, and identification relation about the random inverse packet information are discussed. Finally, based on the above theory, an instance is used to illustrate the applications of intelligent acquisition of investment information.

Presents information on the 2019 IEEE International Conference on Microwaves, Communications, Antennas, and Electronic Systems.

This study aims to optimize the design and performance of three-dimensional (3D) underwater acoustic sensor networks (UASNs). First, we develop an analytical model to quantify network performances in terms of the packet queueing delay and packet error probability for sensors in a 3D UASN. The model considers the retransmission delay due to packet transmission errors and packet collisions when calculating the packet queueing delay. The packet queueing delay depends on the choice of medium access control (MAC) protocol. We consider two different MAC protocols: slotted ALOHA and Request-to-Send and Clear-to-Send (RTS/CTS)-based MAC, which are the representative random access-based and handshake-based MAC protocols for UASNs, respectively. Based on the model, we further determine the smallest data sink density required to meet the desired packet error probability requirement for underwater sensor density, which can help network operators to design and build UASNs in a cost-effective way. To do this, we formulate a simple optimization problem that aims to minimize the data sink density while guaranteeing an upper bound for packet error probability. Using extensive numerical evaluations, network operation strategies are then presented to achieve the desired performance requirements in 3D UASNs.

Earlier the work has analyzed and implemented through IPV4 based traffic. The researchers have address the source IPv4 based routing in MRMC method. The router configures with a standard IPV4 based network extracts the source IPV4 address from the packet Header. This paper has been defined the network topology which was work on IPV6 protocol and it may also support IPV4 protocol. This paper implements the equalization that takes observation of channel state. The stations collect channel state information to their neighboring node, later on it was transfer to Gateway. The collected information was only possible through equalization method. In general, the equalization divided into two ways, per symbol and Sequence based which are according to receiver Theory. We are using sequence based theory under equalization that take data from maximum likelihood neighbors. We were used proposed Hybrid that take the existing method and combine with dynamic channel method. The proposed model avoids the multipath propagation problem and that problem only arise when we changes the channel from one wavelength to another wavelength. This paper showed proposed results that would be analysis the position of the packets in cluster head (CH). The router is taking as the cluster head which is being deployed on the number of nodes and these nodes randomly moves from one location to another. The MATLAB Simulator has been used in this research paper that helps to solve the complex mathematical equation. Network Simulator (NS2) has used to implement the Network Model.

We propose a technique for multiple access communications based on the spatial graph coupling principle. Contrary to the existing approaches that require regularized packet transmission times to create a chain of temporally-coupled packets we present a construction of a self-coupling packet. Each transmitted data packet is encoded and modulated in a way that allows the receiver to perform successful cancellation of the inter-packet interference for the case when the packets are transmitted at random times. We show that the overall system throughput can approach the channel capacity limit. Numerical results demonstrate superior bit-error rates achieved by the self-coupling system compared to the temporal-coupling system.

In this letter, throughput performance of radio frequency (RF) energy harvesting based multihop decode forward relay network with a novel adaptive harvesting scheme is proposed and performance is i...

We propose partial packet duplication; when cellular dual connectivity is available we propose to duplicate only during some portion of the time as needed. This satisfies reliability constraints defined as (1) the probability of fades staying shorter than a certain duration and (2) the probability of non-fades (i.e., time back above the SINR threshold) lasting longer than a certain duration. Fade durations and non-fade durations have been estimated in the literature to fit exponential distributions. We also choose exponential random variables to control duplication processes, which allows Markov chain modeling of the entire process. Using matrix exponential distribution formulations of the Markov chain in the context of partial packet duplication, we fully describe the partial packet duplication behavior, examine asymptotic performance, and define ranges of duplication parameters that meet both fade and non-fade duration constraints. Then we choose the best parameters that minimize resources used on the secondary link for packet duplication.