Amount Of Available Bandwidth Research Articles

Intelligent Spectrum Sharing and Sensing in Cognitive Radio Network by Using AROA (Adaptive Rider Optimization Algorithm)

Wireless spectrum has been allocated to licensees for large geographic areas on a long-term basis in recent years. Cognitive Radio Networks (CRN) will offer mobile users with a huge amount of available bandwidth. Due to spectrum management issues such as spectrum sensing and sharing, CRN networks pose some challenges. Hence in this paper, Adaptive Rider Optimization (AROA) is developed to improve the energy efficiency for different spectrum sensing conditions. The proposed algorithm is utilized to compute the sensing time, sequence length, and detection threshold. In order to detect the spectrum with optimal values of transmission power and sensing bandwidth, the AROA uses the adaptive threshold detection method. The spectrum sensing and sharing of the CRN network are achieved with the help of the AROA algorithm. The proposed method is implemented in MATLAB and the performances such as Normalized Energy consumption, delay, SNR, Jitter, blocking probability, convergence analysis, and Throughput are evaluated. The proposed method is contrasted with the existing methods such as Whale Optimization Algorithm (WOA), Particle Swarm Optimization (PSO), and Grey Wolf Optimization (GWO), respectively.

Comparative Analysis of Max-Throughput and Proportional Fair Scheduling Algorithms in 5G Networks

Mobile network service use is growing, especially after the Covid-19 pandemic. To improve the quality of mobile network services, 5G comes as a network service ecosystem with low latency, which is 1ms, or about 10 times lower than 4G, making 5G able to provide more efficient access, especially in real-time network utilization. Maximum speed can be obtained by sharing limited bandwidth. The limited amount of available bandwidth causes the need for a Packet Scheduler, which aims to improve the efficiency and fairness of bandwidth usage. This research uses two packet schedulers comparing the Proportional Fair algorithm and the Max-Throughput algorithm using test scenarios for changes in the number of users and user speed. The resulting output value analyzes resource limits such as frequency, power, speed, and time in each scenario to allocate resources so that their use remains efficient with a Quality of Service that remains stable and maintained. In simulation testing using the 5G-air-simulator, the average value obtained in the delay is 1,394 ms, throughput is 0,636, and fairness index is 0,967.

Seven Defining Features of Terahertz (THz) Wireless Systems: A Fellowship of Communication and Sensing

Wireless communication at the terahertz (THz) frequency bands (0.1–10 THz) is viewed as one of the cornerstones of tomorrow’s 6G wireless systems. Owing to the large amount of available bandwidth, if properly deployed, THz frequencies can potentially provide significant wireless capacity performance gains and enable high-resolution environment sensing. However, operating a wireless system at high-frequency bands such as THz is limited by a highly uncertain and dynamic channel. Effectively, these channel limitations lead to unreliable intermittent links as a result of an inherently short communication range, and a high susceptibility to blockage and molecular absorption. Consequently, such impediments could disrupt the THz band’s promise of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">high-rate communications and high-resolution sensing</i> capabilities. In this context, this paper panoramically examines the steps needed to efficiently and reliably deploy and operate next-generation THz wireless systems that will synergistically support a fellowship of communication and sensing services. For this purpose, we first set the stage by describing the fundamentals of the THz frequency band. Based on these fundamentals, we characterize and comprehensively investigate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">seven unique defining features of THz wireless systems</i> : 1) Quasi-opticality of the band, 2) THz-tailored wireless architectures, 3) Synergy with lower frequency bands, 4) Joint sensing and communication systems, 5) PHY-layer procedures, 6) Spectrum access techniques, and 7) Real-time network optimization. These seven defining features allow us to shed light on how to re-engineer wireless systems as we know them today so as to make them ready to support THz bands and their unique environments. On the one hand, THz systems benefit from their quasi-opticality and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">can turn every communication challenge into a sensing opportunity</i> , thus contributing to a new generation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">versatile wireless systems</i> that can perform multiple functions beyond basic communications. On the other hand, THz systems can capitalize on the role of intelligent surfaces, lower frequency bands, and machine learning (ML) tools to guarantee a robust system performance. We conclude our exposition by presenting the key THz 6G use cases along with their associated major challenges and open problems. Ultimately, the goal of this article is to chart a forward-looking roadmap that exposes the necessary solutions and milestones for enabling THz frequencies to realize their potential as a game changer for next-generation wireless systems.

Implementation of cognitive radio networks for optimum spectrum utilization through feed forward backpropagation artificial neural network

In wireless Radio Frequency (RF) networks, a huge amount of available bandwidth of the RF spectrum is wasted, because the users are not able to fully utilize the frequency band of the spectrum. The Cognitive Radio Networks provide an effective solution for optimum utilization of the frequency band of the RF spectrum. Cognitive Radio Networks consist of two types of users: primary users, which utilizes their allocated license frequency band of the RF spectrum and secondary users, which uses the license frequency band of the primary users when they are not using the RF spectrum. Primary users pre-empt the secondary users when they want to use the RF spectrum. To know when the spread spectrum is not occupied by the primary users, the secondary users must have some mechanism to sense the environment, learn the parameters and take a decision on the basis of it. The users of Cognitive Radio Networks enhance these capabilities by using Artificial Neural Networks (ANN). This paper discusses how the presence of primary users in the particular frequency band of the spectrum could be detected by the secondary users by using Feed Forward Back Propagation ANN. For this a CRN simulation model is designed and developed which uses a Feed forward back propagation ANN for optimum use of the spectrum.

Optimizing multiple ONUs placement in Fiber-Wireless (FiWi) access network using Grasshopper and Harris Hawks Optimization Algorithms

FiWi network is a multi-domain network that integrates optical and wireless networks. Hybrid fiber-wireless (FiWi) access network endeavours at consolidating the huge amount of available bandwidth of optical networks and the ubiquity, mobility of wireless access networks with the motive of reducing cost and complexity. This manuscript entails investigations undertaken towards optimal placement of multiple Optical Network Units (ONUs) in FiWi network using two recent optimization algorithms named as Harris Hawks Optimization (HHO) and Grasshopper Optimization algorithms (GOA). The results of the investigations are then benchmarked with respect to the Whale Optimization algorithm (WOA). The outcomes demonstrate the superiority of the proposed HHO algorithm over GOA and WOA algorithms, and return the lowest value of cost function; WOA outperforms GOA in terms of improved convergence rate and time complexity. Additionally, the diversification and intensification features of HHO, GOA and WOA have been compared. In order to benchmark the performance of the HHO and GOA optimizers, a series of convergence curves corresponding to different values of controlling parameters are plotted, and their optimal values determined. The dependence of objective function value upon distribution of users and initial placement of ONUs is also studied; the random placement of users and deterministic placement of ONUs return the lowest value of objective function.

Spectrum Handoff by Baum-Welch algorithm for services in Cognitive Radio Networks

Cognitive Radio Networks (CRN) is the upcoming future prospect in 5G networks. Lack of available spectrum is a serious problem in the networking industry nowadays since, for each individual organization only a limited spectrum bandwidth is offered by National Telecommunications and Information Administration (NTIA). The problem arises due to the increase in the number of users who are supposed to use a limited amount of available bandwidth. Using spectrum handoff allows a cognitive user to access the available licensed spectrum in the absence of the primary user in that particular channel. Efficient spectrum sensing has to be done to check the availability of unused spectrum holes. Machine learning models such as Markov model and Hidden Markov model are used to predict the probabilities. In this paper we have presented a model for efficient sensing using Baum-Welch algorithm, a neural network algorithm which can train inner layer channel traits for given sequence of switching services to yield accurate results without huge datasets. Following emission probabilities are obtained for the channels that are trained from transition probabilities of channel services such as video, voice and data. From the obtained probability values each channel can be offered with best suited services.

Path loss model for indoor emergency stairwell environment at millimeter wave band for 5G network

The unused millimeter-wave (mmWave) spectrum offers a superb opportunity to increase mobile broadband capacity due to the enormous amount of available bandwidth. Different candidate operating frequencies for 5G wireless networks are available at the mmWave band. For 5G wireless networks, the emergency case is one of the applications. This paper presents the outcome of indoor emergency stairwell measurement campaigns for 5G system at 26 GHz, 28 GHz, 32 GHz, and 38 GHz, which were conducted at the University Technology Malaysia, Kuala Lumpur, Malaysia. To effectively evaluate the performance of 5G wireless systems in these different bands, single- and multifrequency path loss models are proposed for this environment. This paper proposes a new path loss model based on a new physical anchor point referred to as physical-anchor stair (PAS) path loss model. In a single-frequency large-scale case study, the PAS and the floating intercept (FI) path loss model are investigated at the 20 GHz and 30 GHz bands. Moreover, this study is extended to cover the multifrequency path such as the alpha, beta, and gamma model and the close-in free space path loss model with frequency weight (CIF) model. The CIF model is developed in this paper. The proposed PAS model shows high accuracy (physically based model) and less complexity compared with the studied models. Results show that the path loss exponent values vary between 6.6 and 7.9 for all measured frequencies using the proposed PAS model and between 9.1 and 10.9 using the FI model.

Potentials for Application of Millimeter Wave Communications in Cellular Networks

Future 5G cellular networks will need to deliver significantly increased system capacity and user data rates. This expected growth along with today's shortage of spectrum raises the need for new frequency allocations. Millimeter wave spectrum is emerging as a suitable candidate with a vast amount of available bandwidth (around 60 GHz). Extending cellular networks communications on millimeter wave frequencies requires extensive measurement campaigns and analysis of signals propagation characteristics. This paper gives an overview of recent measurement studies and results used for modeling millimeter wave channel behavior in different propagation environments. Also , the paper provides a preliminary simulation analysis of a hybrid LTE-millimeter wave heterogeneous network, which suggests that Gbps user data rates are achievable with sufficient beamforming gains. However, the millimeter wave cellular extensions will require architectural changes to address the technical issues spanning from the transceivers design to the operational procedures in both access and backhaul network parts.

Performance Analysis of Storage-Based Routing for Circuit-Switched Networks

Circuit-switching technology has been widely used for bulky data transfers due to its advantages over packet switching, such as deterministic delay, guaranteed bandwidth, and low jitter. However, the traditional end-to-end circuit provisioning mechanism may be bottlenecked by the link that has the least amount of available bandwidth. To solve this problem, this paper proposes to deploy storage capacity at intermediate nodes along a path for circuit-switched networks and introduces an efficient routing algorithm that allows different bandwidth allocations from link to link along a path. The simulation results demonstrate that our storage-based approach can efficiently reduce the blocking rate and improve average link utilization and is well suited for delay-insensitive applications.

Mobile Data Offloading Through Caching in Residential 802.11 Wireless Networks

As the ever growing mobile data traffic challenges the economic viability and performance of cellular networks, innovative solutions that harvest idle user-owned network resources are gaining increasing interest. In this work, we propose leasing wireless bandwidth and cache space of residential 802.11 (WiFi) access points (APs) for offloading mobile data. This solution not only reduces cellular network congestion, but, due to caching, improves also the user-perceived network performance without overloading the backhaul links of the APs. To encourage residential users to contribute their bandwidth and cache resources, we design monetary incentive (reimbursement) schemes. The offered reimbursements directly determine the amounts of available bandwidth and cache space in every AP, which in turn affect the caching policy (where to cache each content file) and the routing policy (where to route each mobile data request). In order to reduce operator’s total cost for serving mobile data requests and leasing resources, we introduce a framework for the joint optimization of incentive, caching, and routing policies. Using a novel WiFi usage dataset collected from 167 residences, we show that in densely populated areas with relatively costly network capacity upgrades, our proposal can halve operator’s total cost, while reimbursing up to 9€ per month each residential user.

Network Layer Support for Gigabit TCP Flows in Wireless Mesh Networks

Next generation wireless networks (WMNs) are designed to provide better performance than other existing personal, local, and metropolitan wireless networks, such as Wireless Local Area Networks and WiFi. In WMNs, each link has different amount of available bandwidth, and the bandwidth fluctuates dynamically based on the wireless environment. When the available bandwidth fluctuates, Transmission Control Protocol (TCP) flows experience packet losses, packet re-ordering, and timeouts, resulting in low end-to-end throughput. To alleviate the problem of low TCP throughput, we propose a Spare-bandwidth Rate-adaptive Network Coding (SRNC) scheme. In SRNC scheme, each gateway node forwards packets after network coding. Each intermediate node also adaptively uses network coding before forwarding the packets to the outgoing links. Each mesh access node decodes the network coded packets before forwarding them to the destinations. The key feature of SRNC is that each node adapts its network coding rate based on the available bandwidth on the outgoing links, such that the access nodes can decode the packets with higher probability without significantly affecting the cross-traffic. Effectiveness of the proposed scheme is evaluated using simulation. The simulation results show that the proposed scheme uses the available bandwidth on each link efficiently and it significantly improves end-to-end throughput of TCP flows.

Network virtualization based seamless networking scheme for fiber-wireless (FiWi) networks

In order to reduce cost and complexity, fiber-wireless (FiWi) networks emerge, combining the huge amount of available bandwidth of fiber networks and the flexibility, mobility of wireless networks. However, there is still a long way to go before taking fiber and wireless systems as fully integrated networks. In this paper, we propose a network virtualization based seamless networking scheme for FiWi networks, including hierarchical model, service model, service implementation and dynamic bandwidth assignment (DBA). Then, we evaluate the performance changes after network virtualization is introduced. Throughput for nodes, bandwidth for links and overheads leaded by network virtualization are analyzed. The performance of our proposed networking scheme is evaluated by simulation and real implementations, respectively. The results show that, compared to traditional networking scheme, our scheme has a better performance.

Error Resilient Video Streaming with BCH Code Protection in Wireless Sensor Networks

Video streaming in Wireless Sensor Networks (WSNs) is a promising and challenging application for enabling high-value services. In such a context, the reduced amount ofavailable bandwidth, as well as the low-computational power available for acquiring and processing video frames, imposes the transmission of low resolution images at a low frame rate. Considering the aforementioned limitations, the amount of information carried by each video frame must be considered of utmost importance and preserved, as much as possible, against network losses that could introduce possible artifacts in the reconstructed dynamics of the scene.In this paper we first evaluate the impact of the bit error rate on the quality of the received video stream in a real scenario, then we propose a forward error correction technique based on the use of BCH codes with the aim of preserving the video quality. The proposed technique, against already proposed techniques in the WSN research field, has been specially designed to maintain a full back-compatibility with the IEEE802.15.4 standard in order to create a suitable solution aiming at accomplishing the Internet of Things (IoT) vision. Performance results evaluated in terms of Peak Signal-to-Noise Ratio (PSNR) show that the proposed solution reaches a PSNR improvement of 4.16 dB with respect to an unprotected transmission, while requiring an additional overhead equal to 22.51% in number of transmitted bits, and minimal impact on frame rate reduction and energy consumption. When higher protection levels have been imposed, bigger PSNR values have been experienced at the cost of an increased additional overhead, lower frame rates, and bigger energy consumption values.

Performance evaluation of the survivability schemes in WOBAN: a quality of recovery (QoR) method

SummaryThe hybrid wireless optical broadband access network (WOBAN) is a combination of an optical backhaul and a wireless front‐end, which combine the huge amount of available bandwidth of optical networks and the ubiquity and mobility of wireless access networks with the objective of reducing their cost and complexity. Survivability is one of the most important issues in WOBAN. In this paper, the survivability schemes in WOBAN are addressed from a particular point of view of the quality of recovery (QoR) method. The QoR is a comprehensive measure to evaluate the survivability schemes in terms of availability, recovery time, redundancy, and bandwidth of backup path. The specific procedures to set up the analytical models for the survivability schemes in WOBAN are given based on the QoR concept, including abstract, normalization, and application. Besides, the weights assignment is provided to calculate the QoR value for the operators, home users, or business users with different requirements, which in turn offers the user‐perceptive quality of service. To verify the performance of the survivability schemes by the QoR method, extensive simulations are made under different WOBAN configurations. Numerical results show that for the intra‐domain survivability schemes, the wireless and optical mixed protection scheme is the best choice for failure recovery in WOBAN. The wireless scheme is the second choice for the solution, which emphasizes cost control, while for the solution that emphasizes the network performance, the 1:1 scheme is the second choice. The 1:N scheme obtains the worst QoR value as the splitter ratios increase. For the inter‐domain survivability schemes, optimizing backup optical networking units selection and backup fibers deployment scheme outperforms maximum protection with minimum cost scheme from the point of view of QoR. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Spectrum survey for reliable communications of cognitive radio based smart grid network

The smart grid (SG) system is expected to involve huge amount of data with different levels of priorities to different applications or users. The traditional grid which tend to deploy propriety networks with limited coverage and bandwidth, is not sufficient to support large scale SG network. Cognitive radio (CR) is a promising communication platform for SG network by utilizing potentially all available spectrum resources, subject to interference constraint. In order to develop a reliable communication framework for CR based SG network, thorough investigations on the current radio spectrum are required. This paper presents the spectrum utilization in Malaysia, specifically in the UHF/VHF bands, cellular (GSM 900, GSM 1800 and 3G), WiMAX, ISM and LTE band. The goal is to determine the potential spectrum that can be exploit by the CR users in the SG network. Measurements was conducted for 24 hours to quantify the average spectrum usage and the amount of available bandwidth. The findings in this paper are important to provide insight of actual spectrum utilization prior to developing a reliable communication platform for CR based SG network.

Video streaming applications in wireless camera networks: A change detection based approach targeted to 6LoWPAN

Video streaming applications in wireless camera networks composed by low-end devices are attractive for enabling new pervasive high value services. When complying with the 6LoWPAN standard, the reduced amount of available bandwidth imposes the transmission of low resolution images. In this paper we present a low-complexity algorithm based on background subtraction and error resilience techniques aimed at reducing the transmission bandwidth of a video stream of uncompressed images thus permitting a higher frame rate. By means of realistic simulation studies, the performance of the presented algorithm is analyzed against state-of-the-art solutions like JPEG. These results can be considered for designing a next generation of smart cameras suited for 6LoWPAN.

Arishtat: auction-based dynamic bandwidth allocation method in Ethernet passive optical networks

The increasing applications of networking have caused limitation of dynamic bandwidth allocation (DBA) in next generation access networks such as Ethernet passive optical network (EPON). In this paper, Arishtat, a novel EPON-based DBA method has been proposed that shows advantages over currently available methods. In Arishtat, which is based on the auction theory, optical line terminal runs an auction-based process to effectively register optical network units bandwidth requests and allocates the highest bidders based on the amount of available bandwidth. Simulation results indicate significant improvements comparing to Fair sharing using dual-service-level agreements, and ‘limited service’ interleaved polling with adaptive cycle time methods regarding quality of service parameters such as packet loss, throughput, line utilisation and the execution time of running method.

Biomedical Cloud Computing With Amazon Web Services

In this overview to biomedical computing in the cloud, we discussed two primary ways to use the cloud (a single instance or cluster), provided a detailed example using NGS mapping, and highlighted the associated costs. While many users new to the cloud may assume that entry is as straightforward as uploading an application and selecting an instance type and storage options, we illustrated that there is substantial up-front effort required before an application can make full use of the cloud's vast resources. Our intention was to provide a set of best practices and to illustrate how those apply to a typical application pipeline for biomedical informatics, but also general enough for extrapolation to other types of computational problems. Our mapping example was intended to illustrate how to develop a scalable project and not to compare and contrast alignment algorithms for read mapping and genome assembly. Indeed, with a newer aligner such as Bowtie, it is possible to map the entire African genome using one m2.2xlarge instance in 48 hours for a total cost of approximately $48 in computation time. In our example, we were not concerned with data transfer rates, which are heavily influenced by the amount of available bandwidth, connection latency, and network availability. When transferring large amounts of data to the cloud, bandwidth limitations can be a major bottleneck, and in some cases it is more efficient to simply mail a storage device containing the data to AWS (http://aws.amazon.com/importexport/). More information about cloud computing, detailed cost analysis, and security can be found in references.

Fiber-wireless (FiWi) access networks: Challenges and opportunities

Hybrid fiber-wireless (FiWi) access networks aim at combining the huge amount of available bandwidth of optical networks and the ubiquity and mobility of wireless access networks with the objective to reduce their cost and complexity. This article highlights key enabling optical as well as wireless technologies and explains their role in emerging FiWi networks. After briefly reviewing previous art, important challenges and imperatives for the design of future FiWi network architectures, protocols, and algorithms are identified and discussed in detail.

Linear quadratic control of service rate allocation in a satellite network

The real-time control of multiple queues handling traffic of different nature is obtaining increasing relevance in both the uplink and downlink of wireless telecommunication networks, characterised by the presence of a central access point. Such is the case of satellite networks, with either on-board processing or double-hop configuration, besides a number of terrestrial local and metropolitan wireless networks. Given a certain amount of available bandwidth, the problem is that of deciding, within a certain time frame, the allocation of bandwidth partitions for each traffic queue, whose packets are awaiting transmission; eventually, this determines the transmission rates to be passed to the scheduler and to the physical layer adaptive coding and modulation devices. In a satellite network, where this task is accomplished by a master station, residing at the access point, it is possible to take such decisions by means of a centralised controller, based on real-time instantaneous (in the downstream direction) or delayed (in the upstream) information on the queues' state. The study derives a control law to be used in this task, by adopting an approach based on optimal linear quadratic regulation. Both cases of un-delayed and delayed information are considered. The control laws are tested in a geo-stationary satellite scenario of digital video broadcasting ' return channel via satellite (DVB-RCS), and the queues are considered at the medium access control level. Simulation results under real-traffic traces are also presented to highlight the effectiveness of the control and to compare alternative solutions.