Probability Of Successful Transmission Research Articles

Performance Analysis of Cluster Formation in Wireless Sensor Networks.

Clustered-based wireless sensor networks have been extensively used in the literature in order to achieve considerable energy consumption reductions. However, two aspects of such systems have been largely overlooked. Namely, the transmission probability used during the cluster formation phase and the way in which cluster heads are selected. Both of these issues have an important impact on the performance of the system. For the former, it is common to consider that sensor nodes in a clustered-based Wireless Sensor Network (WSN) use a fixed transmission probability to send control data in order to build the clusters. However, due to the highly variable conditions experienced by these networks, a fixed transmission probability may lead to extra energy consumption. In view of this, three different transmission probability strategies are studied: optimal, fixed and adaptive. In this context, we also investigate cluster head selection schemes, specifically, we consider two intelligent schemes based on the fuzzy C-means and k-medoids algorithms and a random selection with no intelligence. We show that the use of intelligent schemes greatly improves the performance of the system, but their use entails higher complexity and selection delay. The main performance metrics considered in this work are energy consumption, successful transmission probability and cluster formation latency. As an additional feature of this work, we study the effect of errors in the wireless channel and the impact on the performance of the system under the different transmission probability schemes.

Successful transmission probability of cognitive device-to-device communications underlaying cellular networks in the presence of hardware impairments

This paper studies the cognitive wireless powered device-to-device (D2D) communication underlaying a cellular network, where there are two types of communications, including peer-to-peer (P2P) communication and a multi-hop D2D communication, which are assumed to be affected by hardware impairments (HWIs). We investigate the one-hop P2P communication and the multi-hop D2D communication, where the relay node helps other two user equipments (UEs) exchange information with a two-time-slot physical-layer network coding scheme. To examine the system performance, we derive closed-form expressions for the average energy efficiency (EE) and spectral efficiency (SE). Besides that, we also obtain the successful transmission probability (STP) for the two considered communications, and the optimal values of time switching (TS) and power splitting (PS) ratios are achieved with the help of a genetic algorithm (GA)-based optimization algorithm in our proposed energy harvesting (EH) protocol so-called Hybrid TS-PS (HTPS) relaying protocol. Comparisons between amplify-and-forward (AF) and decode-and-forward (DF) transmission schemes are provided. The simulation results give evidence that the STP is significantly improved regardless of the presence of HWIs thanks to the derived parameters, i.e., average EE, SE, and the optimal TS and PS ratios.

Adjustment Delay Scheme to Improve Performance IEEE 802.15.4 Networks

The challenges of CSMA/CA as following: first, when the device nodes detect the channel in busy condition, the device nodes have to increase the value of backoff exponent which cause range of blind backoff process also increase. Second, the blind backoff process will cause lower channel utilization and more energy consumptions. This article proposes a scheme to improve IEEE 802.15.4 medium access control, called adjustment delay scheme (ADES). This article also presents a comprehensive Markov chain analysis to predict the probability of successful transmission, network goodput, bandwidth utilization and total network energy consumption. The validity of the model analysis is proven by precisely matching the simulation experiments. ADES performs better than those of other algorithms in term of the probability of successful packet transmission, network goodput, bandwidth utilization as well as energy consumption in the networks.

Random Access Performance of Distributed Sensors Attacked by Unknown Jammers.

In this paper, we model and investigate the random access (RA) performance of sensor nodes (SN) in a wireless sensor network (WSN). In the WSN, a central head sensor (HS) collects the information from distributed SNs, and jammers disturb the information transmission primarily by generating interference. In this paper, two jamming attacks are considered: power and code jamming. Power jammers (if they are friendly jammers) generate noises and, as a result, degrade the quality of the signal from SNs. Power jamming is equally harmful to all the SNs that are accessing HS and simply induces denial of service (DoS) without any need to hack HS or SNs. On the other hand, code jammers mimic legitimate SNs by sending fake signals and thus need to know certain system parameters that are used by the legitimate SNs. As a result of code jamming, HS falsely allocates radio resources to SNs. The code jamming hence increases the failure probability in sending the information messages, as well as misleads the usage of radio resources. In this paper, we present the probabilities of successful preamble transmission with power ramping according to the jammer types and provide the resulting throughput and delay of information transmission by SNs, respectively. The effect of two jamming attacks on the RA performances is compared with numerical investigation. The results show that, compared to RA without jammers, power and code jamming degrade the throughput by up to 30.3% and 40.5%, respectively, while the delay performance by up to 40.1% and 65.6%, respectively.

Estimation of probabilistic processes in wireless networks of 802.11 standard

The article analyzes mechanisms of collision in a wireless 802.11 network with competitive access to a radio channel. The calculated relationships for determining the probabilities of collisions in the network as a whole in the presence of N active stations with a saturated load, and also for one station when implementing the binary exponential mechanism of increasing the competitive window are presented. The graphs, which illustrate the proposed equations, are given in this article too. An equation is also proposed for determining the probability of successful transmission of a data frame depending on the number of active stations and the initial value of the competitive window. The equations are obtained using the concept of a virtual competitive window.It was shown that in the case, where the number of active stations is one third of the contention window, the probability of collisions is about 0.25. This means that in the network with such number of active stations, each station will experience the collision at every fourth attempt to transmit a frame of data in average. The next attempt to transmit frame of data will be carried out by using the larger contention window. Collisions will cause the increase of transmitting time duration and its irregularity.It was analyzed the efficacy of application of binary exponential law for the change of the contention window for active stations, caught in a conflict when trying to access the channel.The equation for estimate the changes in the probability of collision and the number of competing stations in the access cycle was obtained by taken into account that it will take place when a quasi-stationary mode of operation of wireless networks is established. It was shown that the most effectively this mechanism is triggered in the early stages of repeated access to radio channel. Those stations that carry out the 5-th and 6-th attempts to access channel have a little impact on the probability of collisions on the network. Such result may be explained because every station after successful transmit the data frame will begin a new attempt from the initial meaning of contention window. So, if the initial number of active stations in the wireless network approximately equal to the value of contention window, in steady state of saturated network the effective number of active stations will be twice less due to application of binary exponential law for the change of the competitive window. If the initial number of active stations will be only 30% from the value of contention window, the effective number of active stations will be less twice too.It was gave the estimation of the overall probability of collisions in a saturated 802.11 network with competitive access to the radio channel. The threat of collisions increases quickly in comparison with the increase of number of active stations in the networkFrom the analysis of the received equations and graphs it follows that for the normal operation of the wireless network, it is necessary that the number of active stations that simultaneously compete for access to the radio channel does not exceed a third of the initial value of the contention window used in this network. In this case, the probability of successful transmission will be more than 0.85.Ref. 10, fig. 7.

Wireless Energy Harvesting Sensor Networks: Boolean–Poisson Modeling and Analysis

Wireless radio frequency energy harvesting has been adopted in wireless networks as a method to supply energy to wireless nodes. In this paper, we analyze a wireless energy harvesting network based on a Boolean-Poisson model. This model assumes that energy sources are distributed according to a Poisson point process and have disc-shaped coverage regions with random radii. We introduce a distribution for the coverage radii, which takes aggregated harvested power into account. The union of the coverage regions of the energy sources forms the energy harvesting zone. We derive the transmission success probability of single-hop networks characterized by the probability that two sensor nodes are located in the energy harvesting zone. Then, we analyze the performance of multi-hop networks in the cases, where the locations of the sensor nodes are either fixed or randomly distributed. Moreover, we consider a star-shaped topology, which reflects the scenario wherein some sensor nodes simultaneously transmit data to a data collector. In this setting, we derive an approximation of the average throughput at the data collector. Numerical results validate the accuracy of our analysis in the single-hop and multi-hop networks and confirm the tightness of our approximation in the case of the star-shaped topology.

Sparse and constrained stochastic predictive control for networked systems

This article presents a novel class of control policies for networked control of Lyapunov-stable linear systems with bounded inputs. The control channel is assumed to have i.i.d. Bernoulli packet dropouts and the system is assumed to be affected by additive stochastic noise. Our proposed class of policies is affine in the past dropouts and saturated values of the past disturbances. We further consider a regularization term in a quadratic performance index to promote sparsity in control. We demonstrate how to augment the underlying optimization problem with a constant negative drift constraint to ensure mean-square boundedness of the closed-loop states, yielding a convex quadratic program to be solved periodically online. The states of the closed-loop plant under the receding horizon implementation of the proposed class of policies are mean square bounded for any positive bound on the control and any non-zero probability of successful transmission.

Delay-based user association in heterogeneous networks with Backhaul

The Internet of things (IoT) as an important application of future communication networks puts a high premium on delay issues. Thus when IoT applications meet heterogeneous networks (HetNets) where macro cells are overlaid with small cells, some traditional problems need rethinking. In this paper, we investigate the delay-addressed association problem in two-tier HetNets considering different backhaul technologies. Specifically, millimeter wave and fiber links are used to provide high-capacity backhaul for small cells. We first formulate the user association problem to minimize the total delay which depends on the probability of successful transmission, the number of user terminals (UTs), and the number of base stations (BSs). And then two algorithms for active mode and mixed mode are proposed to minimize the network delay. Simulation results show that algorithms based on mutual selection between UTs and BSs have better performance than those based on distance. And algorithms for mixed modes have less delay than those for active mode when the number of BSs is large enough, compared to the number of UTs.

Fragmentation-Avoiding Spectrum Assignment Strategy Based on Spectrum Partition for Elastic Optical Networks

A fragmentation-avoiding spectrum assignment strategy based on spectrum partition is proposed, which is used to resolve the spectrum fragmentation problem in elastic optical networks. For alleviating spectrum fragmentation, a spectrum partition policy, splitting the whole optical spectrum into several dedicated partitions, is presented. Based on this, a joint first-last-fit spectrum assignment policy is presented to enhance the probability of successful transmission of request and spectrum efficiency, where each partition is first used to transmit requests with the same rate in the first-fit policy; and other partitions are used to search available spectrum resources in the last-fit policy when there are no available spectrum resources in the dedicated partition. Meanwhile, a partition selection formula is designed to minimize the interference of spectrum resources during the last-fit spectrum assignment. Moreover, a reconfiguration mechanism, moving requests that are not transmitted in their dedicated partition to their dedicated partition, is also studied. The simulation results indicate that the proposed algorithm can reduce the bandwidth blocking probability and improve spectrum efficiency.

Mitigating tail latency in IEEE 802.11–based networks

SummaryDelay sensitive applications are being actively introduced with the advent of 5G and vehicular communications, and such applications are very sensitive to tail latency. However, tail latency has not been seriously considered so far, especially in IEEE 802.11–based networks. Channel access is scheduled by random Contention Window (CW) values in IEEE 802.11–based networks, and the node with the larger CW waits longer, and it may even observe multiple transmissions from a single contending node, which results in a long latency tail. In this paper, we propose a new decentralized MAC called SynchMAC to mitigate this latency tail. In SynchMAC, every competing node transmits exactly one packet within a virtual time slot without a centralized controller. Using the proposed approach, the maximum channel access latency is bounded by T×2N, where T is the time required for transmitting a single packet (including Inter‐Frame Space and CW) and N is the number of competing nodes. To maximize the system throughput, the proposed scheme optimizes the value of T by considering the probability of successful transmission. Our simulation study shows that SynchMAC reduces the maximum access latency by up to 94% and 53% compared with the conventional IEEE 802.11 MAC and the comparative scheme, respectively, without degrading throughput performance. We also show that SynchMAC is easily extended to support weighted access.

A Stochastic Geometry Analysis of Large-Scale Cooperative Wireless Networks Powered by Energy Harvesting

Energy harvesting is an emerging technology for enabling green, sustainable, and autonomous wireless networks. In this paper, a large-scale wireless network with energy harvesting transmitters is considered, where a group of transmitters forms a cluster to cooperatively serve a desired receiver amid interference and noise. To characterize the link-level performance, closed-form expressions are derived for the transmission success probability at a receiver in terms of key parameters such as node densities, energy harvesting parameters, channel parameters, and cluster size, for a given cluster geometry. The analysis is further extended to characterize a network-level performance metric, capturing the tradeoff between link quality and the fraction of receivers served. Numerical simulations validate the accuracy of the analytical model. Several useful insights are provided. For example, while more cooperation helps improve the link-level performance, the network-level performance might degrade with the cluster size. Numerical results show that a small cluster size (typically 3 or smaller) optimizes the network-level performance. Furthermore, substantial performance can be extracted with a relatively small energy buffer. Moreover, the utility of having a large energy buffer increases with the energy harvesting rate as well as with the cluster size in sufficiently dense networks.

A distributed ant-based algorithm for routing and wavelength assignment in an optical burst switching flexible spectrum network with transmission impairments

This work describes a distributed algorithm inspired by ant colony optimisation for a solution to the problem of dynamic routing and wavelength assignment with wavelength continuity constraint in optical burst switched networks. The evaluation was conducted in a wavelength division multiplexed network environment with limited number of wavelength channels and in a flexible spectrum network environment undergoing transmission impairments. The simulations in the flexible spectrum network environment aim to replicate the effects of both linear and nonlinear physical layer impairments. Under these effects, an optical burst control packet could be lost during traversal of the network with no measure in place to notify the network of the loss or to free up optical resource reservations. The optical burst switching acknowledgement protocol has been modified in this work to account for a burst control packet failure by implementing a traversal acknowledgement to cater for its loss. The performance of the distributed ant-based algorithm has been extensively evaluated on several network topologies and compared with that obtained by shortest path routing and ant colony routing and wavelength assignment. The results show that the distributed ant-based algorithm significantly improves the burst transmission success probability in the wavelength division multiplexed network environment and provides a good solution in the flexible spectrum network environment undergoing transmission impairments.

Link-Layer Cooperation Based on Distributed TDMA MAC for Vehicular Networks

Cooperative medium access control (MAC) protocols have been proposed for improving communication reliability and throughput in wireless networks. In our previous work, a cooperative MAC scheme called Cooperative ADHOC MAC (CAH-MAC) has been proposed to increase the network throughput under a static networking scenario for vehicular communications. In this paper, we study the effects of relative mobility among nodes and channel fading on the performance of CAH-MAC. In a dynamic networking environment, system performance degrades due to cooperation collisions. To tackle this challenge, we present an enhanced CAH-MAC (eCAH-MAC) scheme, which avoids cooperation collisions and efficiently utilizes cooperation opportunities without disrupting the time-slot reservation operations. Through mathematical analysis and computer simulations, we show that eCAH-MAC increases the effectiveness of node cooperation by increasing utilization of an unreserved time slot. Furthermore, we perform extensive simulations for realistic networking scenarios to investigate the probability of successful cooperative relay transmission and usage of unreserved time slots in eCAH-MAC, in comparison with existing approaches.

Control with erasure channels: performance characterization using an equivalent SNR constrained problem

This paper presents an analytical expression for the optimal stationary performance in the control of multiple-input linear time-invariant (LTI) plants when controlled over erasure channels. In particular, we consider a class of LTI controllers with a data-dropout compensation mechanism. To derive our results, we exploit a statistical equivalence between a feedback system with an erasure channel, and a feedback system with an additive white noise (AWN) channel subject to a signal-to-noise ratio (SNR) constraint. This equivalence allows us to use standard H2 optimization techniques to find an analytical characterization of the optimal performance in terms of the successful transmission probability and plant dynamical characteristics.

Outage and energy-efficiency analysis of cognitive radio networks: A stochastic approach to transmit antenna selection

Cognitive radio networks have recently attracted significant research attention owing to their promise for application in future cellular communication. In this light, given the intense power consumption of wireless networks, considerable research is now being directed at designing random cognitive radio networks with enhanced energy efficiency. In this study, we investigate the outage probability and energy efficiency in a cognitive radio network, modeling the locations of the primary users and cognitive users as a Poisson point process. We derive closed-form expressions for the outage probability and energy efficiency with consideration of the probabilities of unoccupied (not utilized by the primary users) channel selection and successful transmission for imperfect detection in an interference-limited environment of cognitive radio network. Furthermore, we propose a transmit antenna selection method for the cognitive transmitter in such networks and accordingly develop closed-form expressions for the outage probability and energy efficiency. The study reported here highlights the importance of combining the capabilities of unoccupied channel selection and successful transmission in cognitive radio networks to achieve optimal performance regarding outage probability and energy efficiency. In terms of energy efficiency, there is an optimal threshold that maximizes the energy efficiency. For implementation in transmit antenna selection, the outage probability can be significantly decreased by increasing the number of transmit antennas, even though the energy efficiency is maximized at the target outage probability.

P2P-based resource allocation with coalitional game for D2D networks

Device-to-Device (D2D) communication is one of the promising technologies in 5G wireless communication system. The concept of D2D communication is to allow the direct communications between two devices reusing the cellular spectrum. Considering the large scale D2D networks, where multiple D2D users can download common files (called content below) from one or multiple other users directly by reusing the same spectrum with cellular users (CU). In this paper, we propose the peer-to-peer (P2P) based resource allocation for D2D networks in which resource includes spectrum and content. We aim at maximizing the sum download rate based on jointly effective spectrum and content allocation. However, this problem is NP-hard. Thus, we firstly develop a distance constrained coalitional game to solve the optimal resource allocation problem. We formulate the optimal spectrum and content allocation as an utility maximization problem and distribute the utility based on each player’s successful transmission probability (STP) which is derived by the tool of stochastic geometry. By theoretical analysis, we derive the proper constrained distance, prove that the proposed algorithm is Nash-stable and get the improvement of the convergence rate. By extensive simulation, we demonstrate the effectiveness of our proposed algorithm which obtains the best sum download rate comparing with other schemes and it is close to the optimal solution.

Guard Zone Based Interference Management for D2D-Aided Underlaying Cellular Networks

In this paper, the critical issues associated with interference management in device-to-device (D2D) aided underlaying cellular networks are addressed. To mitigate the severe interference imposed by activating D2D links, a guard zone based D2D-activation scheme is proposed by enabling the successive interference cancellation (SIC) capabilities at the base stations (BSs). Furthermore, the exact closed-form expressions for the successful transmission probability (STP) of cellular users (CUEs) are derived by assuming a uniform distribution of both CUEs and D2D users (DUEs) within a given geographical area. After that, the approximated average throughput of CUEs is derived, relying on the method of Taylor-series expansion. In addition, the guard zone's inner radius can be optimized under the criteria of maximizing both STP and average throughput. Numerical results show that both the STP and average throughput of CUEs can be substantially improved by invoking the proposed interference management scheme.

Neighbors-Aware Proportional Fair scheduling for future wireless networks with mixed MAC protocols

In this paper, we consider a beyond-5G scenario, where two types of users, denoted as scheduled and uncoordinated nodes, coexist on the same set of radio resources for sending data to a base station. Scheduled nodes rely solely on a centralized scheduler within the base station for the assignment of resources, while uncoordinated nodes use an unslotted Carrier Sense Multiple Access (CSMA) protocol for channel access. We propose and evaluate through simulations: (a) a novel centralized resource scheduling algorithm, called Neighbors-Aware Proportional Fair (N-PF) and (b) a novel packet length adaptation algorithm, called Channel-Aware (CA) Packet Length Adaptation algorithm for the scheduled nodes. The N-PF algorithm considers the uplink channel state conditions and the number of uncoordinated nodes neighboring each scheduled node in the aggregate scheduling metric, in order to maximize packet transmission success probability. The CA algorithm provides an additional degree of freedom for improving the performance, thanks to the fact that scheduled nodes with lower number of hidden terminals, i.e., having higher packet capture probability, are assigned longer packet transmission opportunities. We consider two benchmark schemes: Proportional Fair (PF) algorithm, as a resource scheduling algorithm, and a discrete uniform distribution (DUD) scheme for packet lengths distribution. Simulation results show that the proposed schemes can result in significant gain in terms of network goodput, without compromising fairness, with respect to two benchmark solutions taken from the literature.

A Fairness Oriented Neighbor-Channel-Aware MAC Protocol for Airborne Sensor Networks.

In airborne sensor networks (ASNs), the media access control (MAC) protocol faces a serious unfairness problem due to the traditional protection mechanism of air-to-air communications among aircraft. Actually, by using the binary exponential back-off algorithm at high traffic loads to minimize collisions among users, the latest successful node can always benefit from this kind of MAC to obtain channel resources. Moreover, when taking the existence of the hidden nodes in ASNs into account, the inaccurate traffic load information will further aggravate the system’s unfairness. In this paper, a neighbor-channel-aware (NCA) protocol is proposed to improve the fairness of MAC protocol in ASNs. In the proposal, the NCA frame is firstly added and exchanged between neighbor nodes periodically, which helps to resolve the inaccurate traffic load information, so as to avoid reducing the probability of successful message transmission. Then a traffic-loading based back-off algorithm is involved to make the neighbor nodes cooperatively adjust the inter-frame space (IFS) interval to further reduce the unfairness. The simulation results show that, the proposed MAC protocol can guarantee the satisfied fairness, simultaneously avoiding heavy network overloads to protect key messages’ successful transmissions in ASNs.

Cooperative Caching Placement in Cache-Enabled D2D Underlaid Cellular Network

In a cache-enabled D2D underlaid cellular network, cooperation of BS caching and D2D caching can further exploit the limited storage capacity and achieve more efficient wireless resource utilization. In this complex network scenario, the closed form expression for successful transmission probability is firstly derived using stochastic geometry, to measure the proportion of users satisfying the delay guarantee. On this basis, a cooperative caching placement problem is formulated to maximize the successful transmission probability. We prove it can be transformed equivalently into a biconvex problem and then a block coordinate descent based algorithm is proposed. Simulation results demonstrate the performance gain of the proposed cooperative caching placement.