Base on the Public Scientific Quality Improvement Research on Risk Early Warning of Online Shopping

LTE-A network offers data rates up to 1 Gbps which is 10?×?faster than LTE catering to growing demand of users. LTE improves user experience by reducing latency and increasing bandwidth efficiency. The emerging services and key enhancements such as Further Enhancement of Downlink Multiple-Input Multiple-Output (MIMO), Heterogeneous Networks, and Carrier Aggregation (CA) in LTE-A has improved performance of LTE-A networks. Scheduling optimization still remains one of the biggest challenges in high speed data transmission network. Scheduling in LTE-A networks are performed at various levels; User Equipment (UE), Serving Gateway (SGW), Air Interface and eNodeB. Remote Radio Head (RRH) is an extremely specialized device installed at antenna of eNodeB for optical to electrical signal conversion, amplification of signals and Uplink and Downlink Scheduling. Resource scheduling at Antenna of eNodeB module is constituted as a significant research optimization area. This paper proposes a soft computing based scheduler for RRH. Results of proposed technique are evaluated on Fairness Index, Throughput, Spectral Efficiency and Rank Indicator Distribution. The proposed algorithm aims to improve performance of scheduling. From experimental results, it is observed that proposed model succeeds to achieve significantly better performance as compared to state-of-art algorithms.

     

Improving quality of experience in wireless VoIP through novel call scheduling

In the last few years we have experienced a dramatic increase in the use of IP networks for voice applications (VoIP) over wireless networks due to increased bandwidth availability and enhanced device capabilities. Since demand often exceeds available capacity, Call Admission Control mechanisms are in place to prevent the uncontrolled usage of bandwidth. Through the use of an intermediary gateway, VoIP calls are in many cases terminated to a normal landline or cellphone; the capacity of such a gateway is also a finite resource since the number of users can vary significantly as many are mobile. In this article we propose an enhanced scheme that aims to manage access to the lines available so that they are used in a fair manner and utilized to the highest degree possible. This management is facilitated by enhancing a proxy implementation with a number of call scheduling policies. The ability to satisfy pending call requests as soon as lines become available, results in increased user service satisfaction. Moreover, it increases line utilization which is crucial from an economic viewpoint. The ultimate goal is to improve Quality of Experience which is deemed as highly important especially considering that wireless network users experience opportunistic and intermittent connectivity.     

IPv6-based dynamic coordinated call admission control mechanism over integrated wireless networks

Many wireless access systems have been developed recently to support users mobility and ubiquitous communication. Nevertheless, these systems always work independently and cannot simultaneously serve users properly. In this paper, we aim to integrate IPv6-based wireless access systems and propose a coordinated call admission control mechanism to utilize the total bandwidth of these systems to minimize the call blocking probabilities, especially the handoff call dropping probabilities. First, we propose an integrated hierarchical wireless architecture over IPv6-based networks to combine the wireless access systems including cellular systems (second-generation, General Packet Radio Service, or third-generation), IEEE 802.11 a/b/g WLAN, and Bluetooth. In the proposed architecture, mobile user can request a call with quality-of-service (QoS) requirements by any wireless network interfaces that can be accessed. When the proposed coordinated call admission control (CCAC) mechanism receives a request, it takes the QoS requirements of the incoming call and the available and reserved bandwidth of this wireless system into consideration to accept or reject this request. Besides, the mechanism can coordinate with other wireless systems dynamically to adjust the bandwidth reserved for handoff calls at each wireless system in this architecture so as to reduce the call blocking probabilities. Once the call is admitted, the mobile user is able to access heterogeneous wireless access networks via multiple interfaces simultaneously. Finally, we evaluate this system to show that the CCAC on the proposed architecture outperforms other mechanisms proposed before.     

无线Mesh网中基于信道感知的多径路由判据

无线Mesh网是一种新型的宽带无线接入网络,其中路由算法的设计是一个非常活跃的研究领域。WCETT路由判据仅适于单径路由协议,但是多路径路由能够提供负载平衡和较高的总带宽。为了提高网络性能,在综合考虑无线链路质量和信道间干扰的基础上,提出了一种新的多径路由判据CAM-WCETT。仿真结果表明,该方案能显著提高网络的吞吐量。     

Smart heterogeneous networks: a 5G paradigm

An exponential growth in data demand on wireless networks and wireless link capacity approaching its theoretical limits, bound us to find new solutions and innovative network designs to handle the enormous amount of traffic. In this paper, we discuss long term evolution-advance (LTE-A) heterogeneous networks (HetNets) being a most effective solution to break this wireless cellular capacity crunch. LTE-A HetNets provide adequate increase in capacity by utilizing multi-tier architecture consisting of different type of cells i.e macro cell, small cell, relay and device to device. However this increase in capacity comes with certain challenges in HetNets outlined in this article. Considering inter cell interference coordination (ICIC) as biggest challenge in LTE-A HetNets, this article surveys state of the art LTE-A HetNets deployments with focus on ICIC. Effective ICIC techniques allow further substantial capacity increase. We give state of the art ICIC on air-interface as well as backhaul strategies for effective ICIC in LTE-A HetNets. Operators perspective of LTE-A HetNets with some insight to future of 5G LTE-A HetNets is provided. We also provide simulation results to show how LTE-A HetNets lead to realize ambitious targets of 5G technology in terms of capacity.     

Optimal DLC protocol configuration for realistic broadband fixed wireless access networks based on ATM

DLC protocols, scheduling, and multiplexing issues for broadband fixed wireless access networks based on ATM are discussed. The established DSA++ mac protocol has been developed at ComNets and has been widely applied within the German project ATMmobil. It has been a fundamental contribution to the etsi bran standardisation of HIPERLAN /2. The DSA++ is here modified to perform optimal within the fixed wireless access network environment. Therefore, realistic traffic as well as radio channel models for the respective scenarios are introduced. Simulation results are presented, showing the feasibility of the respective protocol stack for offering broadband multimedia services with reasonable quality of service. In addition to this advanced protocol approach, two systems are discussed which are currently under standardisation process. The IEEE 802.16 as well as the European hiperaccess systems are both proposed for fixed wireless access networks. Expected scenarios and applications are presented and basic requirements the standards have to fulfil are derived. As another aspect of access networks, their impact on the global information society is discussed.     

TCP traffic performance improving in LTE-A networks

This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.     

Prediction-based secured handover authentication for mobile cloud computing

Mobile cloud computing (MCC) is a new technology that brings cloud computing and mobile networks together. It enhances the quality of service delivered to mobile clients, network operators, and cloud providers. Security in MCC technology, particularly authentication during the handover process, is a big challenge. Current vertical handover authentication protocols encounter different problems such as undesirable delays in real-time applications, the man in the middle attack, and replay attack. In this paper, a new authentication protocol for heterogeneous IEEE 802.11/LTE-A mobile cloud networks are proposed. The proposed protocol is mainly based on the view of the 3GPP access network discovery and selection function, which uses the capacities given by the IEEE 802.11 and the 3GPP long term evolution-advanced (LTE-A) standards interconnection. A prediction scheme, with no additional load over the network, or the user is utilized to handle cloud computing issues arising during authentication in the handover process. The proposed handover authentication protocol outperformed existing protocols in terms of key confidentiality, powerful security, and efficiency which was used to reduce bandwidth consumption.

     

Dynamic spectrum access — concepts and future architectures

New trends and developments in radio technology are enhancing the future capabilities of devices to access electromagnetic spectrum using the full range of dimensions associated with the spectrum. This increased capability, together with current developments towards liberalisation of spectrum management regulations, are opening up opportunities to exploit an emerging paradigm in wireless communications and networking known as dynamic spectrum access (DSA). The key characteristic of DSA networks is their ability to exploit knowledge of their electromagnetic environment to adapt their operation and access to spectrum. Their key promise is that they open the possibility of highly efficient (re)use of spectrum. This paper introduces the main concepts behind DSA, reviews the proposed architectures for future DSA systems, and outlines some of the key research challenges associated with this new paradigm. Particular emphasis will be given to autonomous cognitive radio DSA.     

Sensor-based architecture for QoS provisioning and fast handoff management in WLANs

As wireless local area networks gain popularity from network access providers and customers, supporting multimedia applications becomes a crucial yet unresolved challenge. The need to maintain quality-of-service in the presence of bandwidth limitations, increasing traffic volume and user mobility entails radical rethinking in resource management design in WLANs. The unique capabilities of wireless sensor networks constitute a promising research direction to tackle these issues. In this paper, we present a new sensor-based resource management architecture for enhanced QoS provisioning and handoff management in WLANs. Through theoretical analysis and simulations, we show that the framework can maximize bandwidth utilization while satisfying applications’ QoS requirements and significantly reduce handoff latency.     

Convergence of ethernet PON and IEEE 802.16 broadband access networks and its QoS-aware dynamic bandwidth allocation scheme

IEEE 802.16 and Ethernet Passive Optical Network (EPON) are two promising broadband access technologies for high-capacity wireless access networks and wired access networks, respectively. They each can be deployed to facilitate connection between the end users and the Internet but each of them suffers from some drawbacks if operating separately. To combine the bandwidth advantage of optical networks with the mobility feature of wireless communications, we propose a convergence of EPON and 802.16 networks in this paper. First, this paper starts with presenting the converged network architecture and especially the concept of virtual ONU-BS (VOB). Then, it identifies some unique research issues in this converged network. Second, the paper investigates a dynamic bandwidth allocation (DBA) scheme and its closely associated research issues. This DBA scheme takes into consideration the specific features of the converged network to enable a smooth data transmission across optical and wireless networks, and an end-toend differentiated service to user traffics of diverse QoS (Quality of Service) requirements. This QoS-aware DBA scheme supports bandwidth fairness at the VOB level and class-of-service fairness at the 802.16 subscriber station level. The simulation results show that the proposed DBA scheme operates effectively and efficiently in terms of network throughput, average/maximum delay, resource utilization, service differentiation, etc.     

Enabling seamless multimedia wireless access through QoS‐based bandwidth adaptation

Effective support of real‐time multimedia applications in wireless access networks, viz. cellular networks and wireless LANs, requires a dynamic bandwidth adaptation framework where the bandwidth of an ongoing call is continuously monitored and adjusted. Since bandwidth is a scarce resource in wireless networking, it needs to be carefully allocated amidst competing connections with different Quality of Service (QoS) requirements. In this paper, we propose a new framework called QoS‐adaptive multimedia wireless access (QoS‐AMWA) for supporting heterogeneous traffic with different QoS requirements in wireless cellular networks. The QoS‐AMWA framework combines the following components: (i) a threshold‐based bandwidth allocation policy that gives priority to handoff calls over new calls and prioritizes between different classes of handoff calls by assigning a threshold to each class, (ii) an efficient threshold‐type connection admission control algorithm, and (iii) a bandwidth adaptation algorithm that dynamically adjusts the bandwidth of an ongoing multimedia call to minimize the number of calls receiving lower bandwidth than the requested. The framework can be modeled as a multi‐dimensional Markov chain, and therefore, a product‐form solution is provided. The QoS metrics—new call blocking probability (NCBP), handoff call dropping probability (HCDB), and degradation probability (DP)—are derived. The analytical results are supported by simulation and show that this work improves the service quality by minimizing the handoff call dropping probability and maintaining the bandwidth utilization efficiently. Copyright © 2006 John Wiley & Sons, Ltd.     

TCP Window Control for Variable Bandwidth in Wireless Cellular Networks

Most of TCP schemes in wireless networks assume that the bandwidth of the bottleneck link remains constant over time. However, in wireless cellular networks, to effectively manage the limited resources, the bandwidth is controlled based on radio condition over time. Such varying bandwidth can cause the networks congestion or underutilization. In this letter, we propose a new window control algorithm to improve TCP performance in wireless cellular networks with variable bandwidth. Simulation results illustrate that our proposal improves the performance of TCP in terms of fairness and link utilization     

Proxy‐RED: an AQM scheme for wireless local area networks

Wireless access points (APs) act as bridges between wired and wireless networks. Since the actually available bandwidth in wireless networks is much smaller than the bandwidth in wired networks, there is a disparity in channel capacity which makes the access point a significant network congestion point in the downstream direction. A current architectural trend in wireless local area networks (WLAN) is to move functionality from APs to a centralized gateway in order to reduce cost and improve features. In this paper, we study the use of RED, a well known active queue management (AQM) scheme, and explicit congestion notification (ECN) to handle bandwidth disparity between the wired and the wireless interface of an access point. Then, we propose the Proxy‐RED scheme, as a solution for reducing the AQM overhead from the access point. Simulations‐based performance analysis indicates that the proposed Proxy‐RED scheme improves the overall performance of a network. In particular, the Proxy‐RED scheme significantly reduces packet loss rate and improves goodput for a small buffer, and minimizes delay for a large buffer size. Copyright © 2006 John Wiley & Sons, Ltd.     

Analysis of Phase Noise Issues in Millimeter Wave Systems for 5G Communications

Many varieties of technologies have been introduced for mobile communication and data traffic plays a major role in each generation of communication systems. 5G is termed as Next Generation Wireless Mobile Networks that has higher bandwidth, maximum spectral efficiency, super-speed connection, minimum energy consumption, when compared to 4G wireless networks. Next Generation of Mobile communication will use mmWave frequency bands for 5G systems. Millimeter wave transmission is one of the greatest technology in 5G mobile communication systems having higher bandwidth. It is also considered to be having high user demands and have a mobile growth in coming years. It is a promising technology having a non-shortage bandwidth and traffic demands. The major drawback in this system is Phase noise, In-phase and Quadrature timing mismatch, PAPR, local oscillator noise and blockage effects. The phase noise occurs due to the imperfections in local oscillators. In this paper, we discuss the Phase noise issues in millimeter wave systems. This review will act as guide for researchers to compare the various emerging phase noise problems and mitigation techniques for future 5G wireless networks.

     

On utilization efficiency of backbone bandwidth for a heterogeneous wireless network operator

To provide a comprehensive network access service to wireless users, a network operator may operate different types of wireless networks (such as GPRS, Wi-Fi, HSDPA, UMTS, WiMAX and 3GPP LTE) simultaneously to become a heterogeneous wireless network operator, such as Vodafone and T-Mobile. With convenience of accessing wireless networks, ubiquitous services would stimulate the bandwidth expenditure in the network backbone. Lots of various demanded traffic from heterogeneous access networks may converge toward Internet through the common backbone in the operator. Efficiently utilizing the common backbone can offer a better quality of service to users and maximize the revenues for the operator. To our best knowledge, few studies had ever been made in such a contemporary wireless network environment in the past. In this study, we propose solutions to efficiently allocate the bandwidth for user requests and fully utilize the unused bandwidth in the network backbone owned by the heterogeneous wireless network operator. Our simulation results show that our scheme can increase the utilization of the backbone bandwidth, shorten the request completion time for users and generate more revenue for the operator.     

基于多门限预留机制的自适应带宽分配算法

针对异构无线网络融合环境提出了一种基于多门限预留机制的自适应带宽分配算法,从而为多业务提供QoS保证。该算法采用多宿主传输机制,通过预设各个网络中不同业务的带宽分配门限,并基于各个网络中不同业务和用户的带宽分配矩阵,根据业务k支持的传输速率等级需求和网络状态的变化,将自适应带宽分配问题转化为一个动态优化问题并采用迭代方法来求解,在得到各个网络中不同业务和用户优化的带宽分配矩阵的同时,在带宽预留门限和网络容量的约束条件下实现网络实时吞吐量的最大化,以提高整个异构网络带宽的利用效率。数值仿真结果显示,所提算法能够支持满足QoS需求的传输速率等级,减小了新用户接入异构网络的阻塞概率,提高了平均用户接入率并将网络吞吐量最大提高40%。     

Energy and Latency-Aware Scheduling Under Channel Uncertainties in LTE Networks for Massive IoT

The machine-to-machine (M2M) communication is an enabler technology for internet of things (IoT) that provides communication between machines and devices without human intervention. One of the main challenges in IoT is managing a large number of machine-type communications co-existing with the human to human (H2H) or human type communications. Long term evolution (LTE) and LTE-advanced (LTE-A) technologies due to their inherent characteristics like high capacity and flexibility in data access management are appropriate choices for M2M/IoT systems. In this paper, a two-phase intelligent scheduling mechanism based on interval type-2 fuzzy logic to (1) satisfy QoS requirements, (2) ensure fair resource allocation and (3) control energy level of devices for coexistence of M2M/H2H traffics in LTE-A networks, is presented. The proposed interval type-2 fuzzy Logic mechanism enhances data traffic efficiency by predicting and handling the network uncertainties. The performance of the proposed algorithm is evaluated in terms of various metrics such as delay, throughput, and bandwidth utilization.     

Providing secondary access to licensed spectrum through coordination

Most wireless systems receive a license that gives them exclusive access to a block of spectrum. Exclusivity guarantees adequate quality of service, but it also leads to inefficient use of spectrum. Even when the license holder is idle, no other device can use the spectrum. This paper explores an alternative paradigm for secondary access to spectrum, where a secondary device can transmit when and only when the primary license holder grants permission. In this spectrum usage paradigm, each secondary device makes a request for temporary access to spectrum by providing a primary license holder with information such as its required bandwidth, its required signal to interference ratio, its transmit power, and its location, which is essential for a primary license holder in making an admission decision. This explicit coordination makes it possible to protect the quality of service of both primary and secondary, while gaining the efficiency of spectrum sharing. In this paper, we consider the case where the primary license holder is a GSM-based cellular carrier. We show that our proposed sharing scheme works well even with simple admission control and primitive frequency assignment algorithms. Moreover, imprecise location information does not significantly undermine the performance of our scheme. We also demonstrate that our scheme is attractive to a license holder by showing that a cellular carrier can profit from offering a secondary device access to spectrum at a price lower than it would normally charge a cellular call. Sooksan Panichpapiboon is currently a Ph.D. candidate in the Electrical and Computer Engineering (ECE) Department at Carnegie Mellon University (CMU), Pittsburgh, PA. He received both B.S. and M.S. degrees in electrical and computer engineering from CMU in 2000 and 2002, respectively. His research interests include wireless networks, sensor networks, and performance modeling. Home page: www.andrew.cmu.edu/~sooksan Jon M. Peha (M 87, SM 96) is Associate Director of the CMU Center for Wireless and Broadband Networking at Carnegie Mellon University, and a Full Professor in the Department of Engineering and Public Policy and the Department of Electrical and Computer Engineering. He has served as Chief Technical Officer of successful networking start-ups with products related to wireless networks, video and voice over IP, and secure network payment systems. He has been a member of Legislative Staff in the US Congress, and a member of technical staff at SRI International, AT&T Bell Laboratories, and Microsoft. Dr. Peha also launched a US Government program to assist developing countries with information infrastructure. He holds a Ph.D. in electrical engineering from Stanford. Home page: www.ece.cmu.edu/~peha     

LTE-A系统异构网中的定位技术研究

随着全球移动通信技术的迅猛发展,人们对定位业务的需求日益增强,研究无线定位技术具有很强的实际意义。为了达到4G标准中用户上下行峰值速率,带宽等系统性能要求,引入了长期演进项目的后续演进（LTE-A,Long Term Evolution,Advanced）。目前,LTE-A系统的标准制订工作正在稳步进行中,其中包括了无线定位技术的标准制订,涉及定位方法和重要参量的精度要求。这里对LTE-A系统中宏基站和无线中继设备共存的异构网络中的无线定位技术进行了研究,并结合标准进展提出了一种改进方法。