Application-controlled handover for heterogeneous multiple radios over fibre networks

The wired-wireless integration network can be categorised as fixed mobile convergence (FMC). FMC means the convergence of the existing wired network and wireless network. Therefore a mobile device needs the function of connection and control to the FMC infrastructure. An application-controlled handover is developed, which keeps channel continuity in the wired-wireless synergy network environment that consists of 3G (UMTS) t WLAN t WPAN (UWB) and optical fibre network. A handover mechanism transmits and receives data by using the proposed application selection criteria. It maintains the channel and the seamless transmission from mobile device to the remote optical fibre network, to provide real-time service continuity for multimedia traffic. The results show that application-controlled handover has a reduction up to 83% in packet drop, 74% reduction in bit error rate, 85% reduction in power consumption and 100% enhancement in application response time (delay) as compared with the network without handover technique.     

EAP-FAST在公共无线局域网安全接入控制中的研究及实现

Cisco公司于2004年提出基于隧道的灵活认证协议（EAP-FAST）以替代存在安全漏洞的LEAP认证协议，该协议具有安全性和易部署性的特点。文章论述了基于8021x协议的EAP-FAST认证协议及其实现技术，并在公共无线局域网(PWLAN)综合实验平台上实现了EAP-FAST认证的客户端、认证者、认证服务器端功能。     

基于接入控制器模式的公共无线局域网安全体系设计

公共无线局域网面临网络安全、用户数据保护、身份认证、移动管理及网络服务等多方面的挑战。将现有的公共无线局域网分为WISP—owned,Operator—owned以及for Enterprise 3种类型,并分别讨论了各种类型的特征及其架构。在此基础上提出一种基于接入控制器模式的通用安全体系,可应用于目前大多数类型的公共无线局域网。提出了一种802．1X和Web认证的混合型认证协议,该协议在进行Web认证时将利用802．1X协商后产生的密钥进行,可有效地抵抗窃取服务、基站伪装、消息窃听等攻击,并与现有公共无线局域网Web认证相兼容。     

Adaptive Cell Zooming Strategy Toward Next-Generation Cellular Networks with Joint Transmission

The Internet subscribers are expected to increase up to 69.7% (6 billion) from 45.3% and 25 billion Internet-of-things connections by 2025. Thus, the ubiquitous availability of data-hungry smart multimedia devices urges research attention to reduce the energy consumption in the fifth-generation cloud radio access network to meet the future traffic demand of high data rates. We propose a new cell zooming paradigm based on joint transmission (JT) coordinated multipoint to optimize user connection by controlling the cell coverage in the downlink communications with a hybrid power supply. The endeavoring cell zooming technique adjusts the coverage area in a given cluster based on five different JT schemes, which will help in reducing the overall power consumption with minimum inter-cell interference. We provide heuristic solutions to assess wireless network performances in terms of aggregate throughput, energy efficiency index (EEI), and energy consumption gain under a different scale of network settings. The suggested algorithm allows efficient allocation of resource block and increases energy and spectral efficiency over the conventional location-centric cell zooming mechanism. Extensive system-level simulations show that the proposed framework reduces energy consumption yielding up to 17.5% and increases EEI by 14%. Subsequently, a thorough comparison among different JT-based load shifting schemes is pledged for further validation of varying system bandwidths.     

WiFi6 Dynamic Channel Optimization Method for Fault Tolerance in Power Communication Network

As the scale of power networks has expanded, the demand for multi-service transmission has gradually increased. The emergence of WiFi6 has improved the transmission efficiency and resource utilization of wireless networks. However, it still cannot cope with situations such as wireless access point (AP) failure. To solve this problem, this paper combines orthogonal frequency division multiple access (OFDMA) technology and dynamic channel optimization technology to design a fault-tolerant WiFi6 dynamic resource optimization method for achieving high quality wireless services in a wirelessly covered network even when an AP fails. First, under the premise of AP layout with strong coverage over the whole area, a faulty AP determination method based on beacon frames (BF) is designed. Then, the maximum signal-to-interference ratio (SINR) is used as the principle to select AP reconnection for the affected users. Finally, this paper designs a dynamic access selection model (DASM) for service frames of power Internet of Things (IoTs) and a scheduling access optimization model (SAO-MF) based on multi-frame transmission, which enables access optimization for differentiated services. For the above mechanisms, a heuristic resource allocation algorithm is proposed in SAO-MF. Simulation results show that the method can reduce the delay by 15% and improve the throughput by 55%, ensuring high-quality communication in power wireless networks.     

DQN-Based Proactive Trajectory Planning of UAVs in Multi-Access Edge Computing

The main aim of future mobile networks is to provide secure, reliable, intelligent, and seamless connectivity. It also enables mobile network operators to ensure their customer’s a better quality of service (QoS). Nowadays, Unmanned Aerial Vehicles (UAVs) are a significant part of the mobile network due to their continuously growing use in various applications. For better coverage, cost-effective, and seamless service connectivity and provisioning, UAVs have emerged as the best choice for telco operators. UAVs can be used as flying base stations, edge servers, and relay nodes in mobile networks. On the other side, Multi-access Edge Computing (MEC) technology also emerged in the 5G network to provide a better quality of experience (QoE) to users with different QoS requirements. However, UAVs in a mobile network for coverage enhancement and better QoS face several challenges such as trajectory designing, path planning, optimization, QoS assurance, mobility management, etc. The efficient and proactive path planning and optimization in a highly dynamic environment containing buildings and obstacles are challenging. So, an automated Artificial Intelligence (AI) enabled QoS-aware solution is needed for trajectory planning and optimization. Therefore, this work introduces a well-designed AI and MEC-enabled architecture for a UAVs-assisted future network. It has an efficient Deep Reinforcement Learning (DRL) algorithm for real-time and proactive trajectory planning and optimization. It also fulfills QoS-aware service provisioning. A greedy-policy approach is used to maximize the long-term reward for serving more users with QoS. Simulation results reveal the superiority of the proposed DRL mechanism for energy-efficient and QoS-aware trajectory planning over the existing models.     

MIMO-Terahertz in 6G Nano-Communications: Channel Modeling and Analysis

With the development of wireless mobile communication technology, the demand for wireless communication rate and frequency increases year by year. Existing wireless mobile communication frequency tends to be saturated, which demands for new solutions. Terahertz (THz) communication has great potential for the future mobile communications (Beyond 5G), and is also an important technique for the high data rate transmission in spatial information network. THz communication has great application prospects in military-civilian integration and coordinated development. In China, important breakthroughs have been achieved for the key techniques of THz high data rate communications, which is practically keeping up with the most advanced technological level in the world. Therefore, further intensifying efforts on the development of THz communication have the strategic importance for China in leading the development of future wireless communication techniques and the standardization process of Beyond 5G. This paper analyzes the performance of the MIMO channel in the Terahertz (THz) band and a discrete mathematical method is used to propose a novel channel model. Then, a channel capacity model is proposed by the combination of path loss and molecular absorption in the THz band based on the CSI at the receiver. Simulation results show that the integration of MIMO in the THz band gives better data rate and channel capacity as compared with a single channel.     

Quintuple Band Antenna for Wireless Applications with Small Form Factor

A coplanar waveguide-fed quintuple band antenna with a slotted circular-shaped radiator for wireless applications with a high isolation between adjacent bands is presented in this paper. The proposed antenna resonates at multiple frequencies with corresponding center frequencies of 2.35, 4.92, 5.75, 6.52, and 8.46 GHz. The intended functionality is achieved by introducing a circular disc radiator with five slots and a U-shaped slot in the feed. The proposed antenna exhibits coverage of the maximum set of wireless applications, such as satellite communication, worldwide interoperability for microwave access, wireless local area network (WLAN), long-distance radio telecommunications, and X-band/Satcom wireless applications. The simulation and measurement results of the proposed fabricated antenna demonstrate the high isolation between adjacent bands. A stable realized gain with an advantageous radiation pattern is achieved at the operating frequency bands. The proposed simple design, compact structure, and simple feeding technique make this antenna suitable for integration in several wireless communication applications, where the portability of devices is a significant concern. The proposed antenna is anticipated to be an appropriate candidate for WLAN, long-term evolution, and fifth-generation mobile communication because of its multi-operational bands and compact size for handheld devices.     

A privacy-preserving authentication protocol with secure handovers for the LTE/LTE-A networks

Long-Term Evolution/Long-Term Evolution Advanced (LTE/LTE-A) is the latest mobile communication technology that is offering high data rates and robust performance to the subscribers. Since LTE/LTE-A standards are established on the Internet Protocol (IP) connectivity and provide compatibility with the heterogeneous networks, these new features create availability of the new security challenges in the LTE/LTE-A networks. Taking into consideration the issues of serious signalling congestion and security loopholes in LTE/LTE-A networks, the authors propose an Efficient Authentication and Key Agreement Protocol for Evolved Packet System (EAKA-EPS) with secure handover procedures. The proposed protocol achieves outstanding results in terms of the optimization of computation and signalling overhead. With this, the protocol guarantees the needed security requirements like protected wireless interface and strong mutual authentication between the entities, and ensures access stratum secrecy at the time of handovers. The formal verification results of the proposed scheme over the security verification and simulation tool “Automated Validation of Internet Security Protocols and Applications (AVISPA)” show that the suggested protocol is safe against various malicious attacks, which are still possible in LTE/LTE-A networks. To the best of the authors’ knowledge, the suggested approach is the first approach that provides perfect secrecy with less computation and communication overhead in the LTE/LTE-A networks.     

Adaptive bandwidth sharing mechanism for quality of service administration in infrastructure wireless networks

In infrastructure wireless networks, the wireless hop can be considered as another hop of the transmission path. With the rapid growth of wireless traffics, the future wireless network is expected to provide services for heterogeneous data traffics with different quality of service (QoS) requirements. Most proposed schemes do not have adaptive mechanisms to deal with the environment changes. In real situation, bandwidths, error rates and loss rates of wireless links vary frequently. We will base on the differentiated service model and propose a wireless differentiation (WD) scheme for user datagram protocol (UDP) flows and a wireless differentiation with prioritised ACK scheme for connections with transmission control protocol (TCP) flows. Both schemes provide QoS support for IEEE 802.11b and do not change the basic access mechanism of IEEE 802.11b.     

A Blockchain-Based Authentication Protocol for WLAN Mesh Security Access

In order to deploy a secure WLAN mesh network, authentication of both users and APs is needed, and a secure authentication mechanism should be employed. However, some additional configurations of trusted third party agencies are still needed on-site to deploy a secure authentication system. This paper proposes a new block chain-based authentication protocol for WLAN mesh security access, to reduce the deployment costs and resolve the issues of requiring key delivery and central server during IEEE 802.11X authentication. This method takes the user’s authentication request as a transaction, considers all the authentication records in the mesh network as the public ledger and realizes the effective monitoring of the malicious attack. Finally, this paper analyzes the security of the protocol in detail, and proves that the new method can solve the dependence of the authentication node on PKI and CA.     

无线接入点WAPI认证机制的研究与实现

随着无线局域网技术的广泛应用，新的无线局域网安全标准被提出以增强无线局域网的安全性能。在分析WAPI(WLAN Authentication and Privacy Infrastructure)标准的技术特征和基本架构的基础上，介绍了无线接入点对WAPI认证机制的实现机理和具体流程，并对WAPI认证机制的性能进行测试分析。     

Transmission Control under Multi-Service Disciplines in Wireless Sensor Networks

The wireless sensor network (WSN), as the terminal data acquisition system of the 5G network, has attracted attention due to advantages such as low cost and easy deployment. Its development is mainly restricted by energy. The traditional transmission control scheme is not suitable for WSNs due to the significant information interaction. A switchable transmission control scheme for WSNs based on a queuing game (SQGTC) is proposed to improve network performance. Considering that sensor nodes compete for the resources of sink nodes to realize data transmission, the competitive relationship between nodes is described from the perspective of a game. Different types of sensor node requests require a sink node to provide different service disciplines. Mathematical models of social welfare are established for a sink node under the service disciplines of first-come, first-served (FCFS), egalitarian processor sharing (EPS), and shortest service first (SSF). The optimal service strategies are obtained by maximizing social welfare. The sensor nodes provide the expected benefits and satisfy the service requirements of the requests, and the sink node switches the transmission control strategy for the service. Simulation results show that the proposed scheme improves the data transmission efficiency of WSNs and achieves the optimal allocation of resources.     

Proxy handoff support for multi-ISP heterogeneous networks

Due to the reusable characteristic of cache, proxy servers are widespread to improve the quality of network services. As popularity and maturity of wireless access technologies continue to grow, 3G/3.5G, Wi-Fi, or WiMAX mobile nodes (MNs) may keep moving across heterogeneous networks. It is unreasonable to let MNs retrieve cached data from the same proxy server along their traveling routes. Hence, proxy handoff is meant to help MNs switch their proxies dynamically. Regarding the realistic network environment, most proxies are provided by Internet service providers (ISP). Once a MN moves across the domain of one ISP, it can not access the data cached in the proxy. This kind of proxy access limitation obstructs cache cooperation and forwarding among proxies. This article is motivated to utilize the Session Initiation Protocol and the mobile agent concept to propose a proxy handoff framework for multi-ISP heterogeneous networks. Different strategies are designed to overcome proxy access limitation. The simulation results compare and analyze the differentiation among three proxy handoff strategies.     

WLAN 802.11/11b数据加密机制的安全分析

在802.11标准中的加密采用WEP协议，用于提供链路层数据传输的安全保护。目前，在原有EP的基础上提出了一些改进方案，能提高WEP的安全性能，但理论上缺少严密的安全分析。笔者通过数学模型对这些解决方案以及原有WEP协议进行量化分析，推导出机制内各模块与整个安全机制间安全性能的对应函数关系，并比较了这些方案间安全性能的差异，证明这些安全机制可以提高原有WEP的安全性能，在理论上为用户提供如何构造满足所需安全性能的WLAN数据加密增强机制。     

Mobility model for heterogeneous wireless networks and its application in common radio resource management

User distribution and mobility behaviour vary based on environment types and characteristics. Heterogeneous wireless networks (HWNs) are deployed to utilise these characteristics and serve users with better quality. For efficient resource management in HWN environment, an understanding of multi-mode user mobility behaviour is paramount. Here, a multi-mode user mobility model is proposed in the context of wireless local area network (WLAN) coverage in the hotspot, overlaid on a macrocell of wireless wide area network (WWAN). An expression for microcell residence time of multi-mode users in HWNs is derived, based on the cell residence time in the constituting WLAN and WWAN. The boundary-crossing probabilities of moving into microcell, moving out of microcell and moving out of macrocell during a call for different types of hotspot topologies are also derived analytically. The numerical results obtained using the analytical expressions for boundary-crossing probability are validated by simulation results. The significance of the proposed mobility model is demonstrated through its application in common radio resource management (CRRM). Numerical results show that the mobility-based CRRM scheme exhibits a lower rate of unnecessary vertical handoffs than that achieved by the dasiaWLAN' if coveragedasia scheme that does not use mobility information for resource management.     

Job partition and allocation using the prediction model in non-dedicated heterogeneous wireless network environments

Adapting wireless devices to communicate within grid networks empower users. This makes deployment of a wide range of applications possible within appropriate limits, including intermittent network connectivity and non-dedicated heterogeneous system capacity. The performance prediction model is used to improve the performance of the mobile grid job scheduling algorithm (MG-JSA). The proposed algorithm predicts the response time for processing the distributed application in each mobile node, although considering wireless network environments and inherent non-dedicated heterogeneous system capacity. Using this prediction model, the algorithm partitions and allocates the distributed jobs to available mobile nodes for rapid job processing. The efficiency of the MG-JSA model is demonstrated by evaluating its performance.     

基于安全Web服务的网络管理技术的性能研究

实现了基于安全Web服务(WS)的网络管理的原型.研究了在读取不同对象数的情况下,由于消息认证和加密而增加的计算负担对网络性能的影响,并获得了WS在不同的安全等级以及是否压缩的情况下性能与读取对象数之间的关系.同时,对安全WS和SNMPv3在带宽使用情况和往返时延方面的性能进行了深入研究,结果表明,WS由于加入了安全(认证和加密)机制而增加了计算负担,但是在读取大量对象数时,压缩的安全WS的性能优于SNMPv3的性能,而且安全功能所增加的负担并不会影响网络的正常运行.     

Novel web agent framework to support seamless mobility for data networks

In this study, the authors address a mobile web agent framework based on stream control transmission protocol (SCTP) to overcome the deficiencies, which the typical mobile web agent framework based on transmission control protocol (TCP) suffers from, such as performance degradation, head-of-line blocking and unsupported mobility in mobile wireless environment. The proposed SCTP-based mobile web agent framework supports seamless transport layer mobility in a ubiquitous environment. It consists of an application engine and a transport engine, to use the hypertext transfer protocol and to deploy SCTP with dynamic address reconfiguration, respectively. The authors explore and describe the components necessary to implement the proposed mobile web agent framework in an ubiquitous environment. The performance of the proposed SCTP-based mobile web agent is compared with that of a typical TCP-based mobile web agent using ns-2 simulator. The simulation results show that the proposed web agent based on SCTP has a remarkably lower mean response time than a typical web agent based on TCP.     

VoIP原理及其在无线局域网中的QoS保障

VoIP技术现正成为一项构建语音网络的重要技术。本文介绍了VoIP的基本原理,以及VoIP在无线局域网中的应用,分析了无线VoIP业务质量中的问题及解决方法。通过某VoIP无线局域网实例说明了WLAN VoIP的结构和配置,并结合VoIP话音质量评价标准,从无线VoIP传送话音所存在的问题出发,着重探讨了解决这些问题的方法。