TD-SCDMA R4与HSDPA的混合组网

为适应越来越高的数据业务需求，原有的TD-SCDMA的峰值速率已经无法满足需求，HSDPA技术的发展为更高的数据速率和更高容量提供了一条平稳演进的途径。在TD-SCDMA系统组网方案的基础上，如何引入HSDPA越来越受到人们的重视。随着移动通信和互联网的迅速发展，视频、流媒体等许多对流量和延迟性能要求较高的数据业务对移动通信系统提出了更高的要求。在这种情况下，第三代移动通信系统原来所提出的的2Mbit／s的峰值速率目标已经无法满足市场的需求，因此，3GPP在R5以后的版本中引入了新的分组接入增强技术HSDPA，将TD-SCDMA的峰值速率提高到2．8Mbit／s。考虑建设成本和经济效益的结合，HSDPA可以采用和R4版本系统的混合组网方式。本文在讨论TD—SCDMA HSDPA关键技术发展的基础上，对R4版本和HSDPA系统的混合组网方案进行了研究。[编者按]     

LTE-A引领MBB新纪元

1引言2011年一季度,3GPP发布了第一个LTE-A协议版本R10。LTE-A是LTE的演进技术,满足IMT-A第4代移动通信系统的所有需求。LTE-A技术大大提高了无线通信系统的峰值速率、峰值频谱效率、平均速率、平均频谱效率、小区边缘用户性能,也能提高整个网络的组网效率,将成为未来无线通信技术发展的主流,引领MBB...     

TD-SCDMA多载波HSDPA技术

HSDPA技术是提高3G网络下行容量和数据业务速率的一种重要技术。为了使TD—SCDMA系统与其它系统相比具有相当的竞争优势，提出了多载波HSDPA技术，将HSDPA技术与多频点技术相结合，通过多载波捆绑提高TD—SCDMAHSDPA系统中单用户峰值速率。介绍了多载波技术方案的设计原则和URAN侧设计和TD—SCDMA多载波HSDPA标准化情况。     

5G RedCap技术的演进和应用

作为3GPP R17版本中极其重要的技术，RedCap凸显了填补中高速物联网领域的重要技术创新。文中介绍了Rel-17 RedCap在典型应用场景中的应用，分析了其关键技术，估算了RedCap在不同频段的峰值速率，并研究了其在不同频段中应用的特点，最后对5G RedCap的商用前景进行了分析和展望。     

HSDPA技术特点及其部署策略

HSDPA（High Speed Download Packet Access）即高速下行分组接入，它是3GPP在R5协议中为了满足上／下行数据业务不对称的需求而提出的一种技术。HSDPA基本上继承了3GPPR99定义的许多性能，且又大大地增强了移动数据传输下行链路的峰值速率和吞吐量并降低了传输时延，它把下行数据业务速率提高到10Mbiffs。该技术是WCDMAR99／R4网络提高下行容量和数据业务速率的一种重要技术。     

LTE-A下行单用户MIMO增强技术研究

无线通信系统中,基站可以针对信道空间特性采用不同的下行传输模式获得空间复用增益和波束成形增益以提升系统性能。LTE-A中的下行单用户MIMO增强技术,采用了基于码本以及非码本的预编码技术优化性能,有必要分析其技术特点和增益来源以指导产品设计。分析了LTE-A中单用户MIMO技术演进的新特点,着重研究了新的双码本结构,在对信道属性匹配、码本搜索运算复杂度和UE上报载荷方面的改进。针对LTE-A预编码技术性能问题,通过计算机链路级仿真比较了LTE—A中基于码本以及非码本预编码技术的吞吐量性能,仿真结果表明码本技术较非码本技术具有一定优势。     

TD-HSDPA技术及其对网络规划的影响

3GPP在R5版本中提出了HSDPA(高速下行分组接入)。HSDPA通过采用AMC、HARQ、高阶调制(16QAM)等技术,在基站侧实现快速调度,从而可以快速自适应地反映用户信道的变化,获得较高的用户峰值速率和小区数据吞吐量。HSDPA的单载波(上下行时隙比例为1:5)理论峰值速率可达2.8Mb/s。烽火     

TD-SCDMA HSUPA技术

时分同步码分多址（TD—SCDMA）上行增强技术的主要目的是改善上行性能，显著提高上行分组数据的峰值传输速率，以及提高上行分组数据的总体吞吐量，同时减少传输延迟。为了改善上行性能，高速上行分组接入（HSUPA）主要考虑的技术包括自适应调制编码（AMC）、混合自动重传（HARQ）、节点B（NodeB）快速调度，以及用户终端（UE）如何共享上行信道资源，同时包括增加增强的媒体访问控制（MAC—e／es）实体，对协议进行增强和优化。对上述技术的可行性进行研究和评估后，结果表明可以显著改善系统性能（包括峰值速率、吞吐量和时延）。     

HSDPA数据业务优化案例分析

HSDPA(高速下行分组接入)技术是WCDMA系统R5协议中引入的无线增强技术,它可以为下行提供高达13.9Mbps的峰值速率,提高了小区吞吐量、服务质量,改善了下行分组数据业务的频谱效率。然而新的应用对无线网络运营产生了很高的要求,有效的网络优化可以解决网络的通信忙点和盲点,保证网络稳定高效运行。文章给出HSDPA数据业务优化的实际案例,对案例中的现象进行分析和优化,使得HSDPA数据业务性能得以改善。     

HSDPA数据业务优化案例分析

HSDPA（高速下行分组接入）技术是WCDMA系统R5协议中引入的无线增强技术,它可以为下行提供高达13.9Mbps的峰值速率,提高了小区吞吐量、服务质量,改善了下行分组数据业务的频谱效率。然而新的应用对无线网络运营产生了很高的要求,有效的网络优化可以解决网络的通信忙点和盲点,保证网络稳定高效运行。文章给出HSDPA数据业务优化的实际案例,对案例中的现象进行分析和优化,使得HSDPA数据业务性能得以改善。     

A Generic Framework for Mobility Modeling and Performance Analysis in Next-Generation Heterogeneous Wireless Networks

Integration of different wireless radio cellular technologies is emerging as an effective approach to accommodate the increasing demand of next-generation multimedia-based applications. In such systems user roaming among different technologies, commonly known as vertical handoff, will significantly affect different aspects of network design and planning due to the characteristically wide-ranging diversity in access technologies and supported applications. Hence, the development of new mobility models that accurately depict vertical mobility is crucial for studying different design problems in these heterogeneous systems. This article presents a generic framework for mobility modeling and performance analysis of integrated heterogeneous networks using phase-type distributions. This framework realizes all modeling requirements in next-generation user mobility including accuracy, analytical tractability, and accommodating the correlation between different residence times within different access technologies. Additionally, we present general guidelines to evaluate application performance based on the new mobility models introduced in this article. We show the accuracy of our modeling approach through simulation and analysis given different applications.     

Thorough empirical analysis of the IETF FMIPv6 protocol over IEEE 802.11 networks [architectures and protocols for mobility management in all-IP mobile networks]

The development of network technologies such as wireless LAN have made it possible for users to benefit from Internet connectivity almost anywhere and at anytime. In order to improve user experience, the IETF has defined the Mobile IPv6 protocol which allows mobile nodes to maintain their communication uninterrupted while roaming across various IPv6 subnets. However, the mechanisms this protocol defines may cause undesired connection disruption and/or substantial packet loss which may significantly degrade the quality of real-time media streams. To address the problems of handover latency, the Mipshop IETF working group has adopted and developed the FMIPv6 protocol. Previous analysis, including some of our own, has shown that the protocol is particularly efficient in reducing both the duration of handovers and the number of lost packets. However, these previous works are often based on theoretical studies and simulations, or do not analyze all FMIPv6 operations and features. We therefore present in this article a thorough experimental evaluation of FMIPv6 over wireless LANs. This article extends our previous work by evaluating all aspects of FMIPv6: predictive handovers, reactive handovers, and network-initiated handovers. We also evaluate the benefits of FMIPv6 on layer 2 only handovers. All experiments are conducted with unmodified versions of the popular conferencing and video streaming applications Gnomemeeting and VLC.     

An active networking based service for media transcoding in multicast sessions

Active networking is one of the suggested technologies to introduce additional intelligence and programmability in the network and its services. In this paper, the use of active networking to support advanced multicast services providing media transcoding inside the network is investigated. In the multicast service different versions of the streamed data are made available and customers can select a specific version according to their wishes or their capabilities. Based on the active networking facilities of the underlying framework the different versions of the streamed data can be created inside the network, through transformations or transcodings of the original data. Both design and performance issues of the detailed service are discussed. A new multicast tree set-up protocol, taking into account the required transcodings, is introduced. A number of different strategies are discussed optimizing the location of the transcodings as well as the use of bandwidth in the network, while considering the availability of sufficient processing power in the nodes. The performance analysis is done for a voice stream multicast service, addressing the efficiency of the tree set-up strategies, the optimization of network resource utilization, the use of processing power for transcodings, and the resulting quality of streamed voice signals after multiple transcodings.     

ELAKA: Energy-Efficient and Lightweight Multi-Server Authentication and Key Agreement Protocol Based on Dynamic Biometrics

Authentication and key agreement (AKA) provides flexible and convenient sercices. Most traditional AKA protocols are designed to apply in single-server environment, where a user has to register at different servers to access different types of network services and the user have to remember or manage a large number of usernames and passwords. Later, multi-server AKA protocols resolve the repeated registration problem of single-server AKA protocols, where a user can access different servers to get different services using a single registration and the same username and password. Recently, in 2015, Lu et al proposed a light-weight ID based authentication and key agreement protocol for multi-server architecture, referred to as LAKA protocol. They claimed their protocol can overcome all shortcomings which existed in Xue et al’s protocol. Unfortunately, our further research shows that LAKA protocol still suffers from server spoofing attack, stolen smart card attack etc. To overcome the weakness of LAKA protocol, an energy-efficient and lightweight authentication and key agreement protocol for multi-server architecture is proposed (abbreviated to ELAKA). The ELAKA protocol not only provides the security features declared by LAKA protocol, but also has some other advantages. First, the ELAKA protocol can realize authentication and key agreement just by three handshakes with extremely low communication cost and computation cost between users and servers, which can achieve a delicate balance of security and performance. Second, ELAKA protocol can enable the user enjoy the remote services with privacy protection. Finally the ELAKA protocol is proved secure against known possible attacks by using BAN logic. As a result, these features make ELAKA protocol is very suitable for computation-limited mobile devices (such as smartphone, PAD, tablets) in comparison to other related existing protocols.     

An efficient and secure 3‐factor user‐authentication protocol for multiserver environment

In the last decade, the number of web‐based applications is increasing rapidly, which leads to high demand for user authentication protocol for multiserver environment. Many user‐authentication protocols have been proposed for different applications. Unfortunately, most of them either have some security weaknesses or suffer from unsatisfactory performance. Recently, Ali and Pal proposed a three‐factor user‐authentication protocol for multiserver environment. They claimed that their protocol can provide mutual authentication and is secure against many kinds of attacks. However, we find that Ali and Pal's protocol cannot provide user anonymity and is vulnerable to 4 kinds of attacks. To enhance security, we propose a new user‐authentication protocol for multiserver environment. Then, we provide a formal security analysis and a security discussion, which indicate our protocol is provably secure and can withstand various attacks. Besides, we present a performance analysis to show that our protocol is efficient and practical for real industrial environment.     

Machine Learning Protocol for Secure 5G Handovers

The fifth generation (5G) networks are characterized with ultra-dense deployment of base stations with limited footprint. Consequently, user equipment’s handover frequently as they move within 5G networks. In addition, 5G requirements of ultra-low latencies imply that handovers should be executed swiftly to minimize service disruptions. To preserve security and privacy while at the same time maintaining optimal performance during handovers, numerous schemes have been developed. However, majority of these techniques are either limited to security and privacy or address only performance aspect of the handover mechanism. As such, there is need for a novel handover authentication protocol that addresses security, privacy and performance simultaneously. This paper presents a machine learning protocol that not only facilitates optimal selection of target cell but also upholds both security and privacy during handovers. Formal security analysis using the widely adopted Burrows–Abadi–Needham (BAN) logic shows that the proposed protocol achieves all the six formulated under this proof. As such, the proposed protocol facilitates strong and secure mutual authentication among the communicating entities before generating the shares session key. The derived session key protected the exchanged packets to avert attacks such as forgery. In addition, informal security evaluation of the proposed protocol shows that it offers perfect forward key secrecy, mutual authentication any user anonymity. It is also demonstrated to be robust against attacks such as denial of service (DoS), man-in-the-middle (MitM), masquerade, packet replays and forgery. In terms of performance, simulation results shows that it has lower packets drop rate and ping–pong rate, with higher ratio of packets received compared with improved 5G authentication and key agreement (5G AKA’) protocol. Specifically, using 5G AKA’ as the basis, the proposed protocol reduces the handover rate by 94.4%, hence the resulting handover signaling is greatly minimized.

     

Mobility support in wireless Internet

The tremendous advancement and popularity of wireless access technologies necessitates the convergence of multimedia (audio, video, and text) services on a unified global (seamless) network infrastructure. Circuit-switched proprietary telecommunication networks are evolving toward more cost-effective and uniform packet-switched networks such as those based on IP. However, one of the key challenges for the deployment of such wireless Internet infrastructure is to efficiently manage user mobility. To provide seamless services to mobile users, several protocols have been proposed over the years targeting different layers in the network protocol stack. In this article we present a cross-layer perspective on the mobility protocols by identifying the key features of their design principles and performance issues. An analysis of the signaling overhead and handoff delay for some representative protocols in each layer is also presented. Our conclusion is that although the application layer protocol is worse than the protocols operating in the lower layers, in terms of handoff delay and signaling overhead, it is better suited as a potential mobility solution for the next-generation heterogeneous networks, if we consider such factors as protocol stack modification, infrastructure change, and inherent operational complexity.     

用于万网互联的网络层协议体系

通过对现有网络协议技术演进历史的分析,试图提出适用于未来数据网络统一协议体系的创新指导原则。通过将网络功能本质划分到网元和网元之间的联系,提出了数据面、控制面、用户面、管理控制类与内生网络安全等协议创新的 5 个领域,并分析了该协议体系在众多异构场景网络中的体现与应用。最后,通过分析确定性网络转发技术中的协议创新过程验证了协议体系创新指导原则的合理性。     

个人通信系统中的一种移动用户登记认证协议

假冒和窃听攻击是无线通信面临的主要威胁。在个人通信系统中,为了对无线链路提供安全保护,必须对链路上所传送的数据/话音进行加密,而且在用户与服务网络之间必须进行相互认证。近年来,人们在不同的移动通信网络(如GSM,IS-41,CDPD,Wireless LAN等)中提出了许多安全协议。然而,这些协议在个人通信环境中应用时存在不同的弱点。本文基于个人通信系统的双钥保密与认证模型,设计了用户位置登记认证协议;并采用BAN认证逻辑对协议的安全性进行了形式化证明,也对协议的计算复杂性进行了定性分析。分析表明,所提出的协议与现有的协议相比具有许多新的安全特性。     

Reactive routing for mobile cognitive radio ad hoc networks

Although more than a decade has passed from the proposal of the Cognitive Radio paradigm, in these years the research has mainly focused on physical and medium access issues, and few recent works focused on the problem of routing in cognitive networks. This paper addresses such a problem by evaluating the feasibility of reactive routing for mobile cognitive radio ad hoc networks. More specifically, we design a reactive routing protocol for the considered scenario able to achieve three goals: (i) to avoid interferences to primary users during both route formation and data forwarding; (ii) to perform a joint path and channel selection at each forwarder; (iii) to take advantage of the availability of multiple channels to improve the overall performance. Two different versions of the same protocol, referred to as Cognitive Ad-hoc On-demand Distance Vector (CAODV), are presented. The first version exploits inter-route spectrum diversity, while the second one exploits intra-route spectrum diversity. An exhaustive performance analysis of both the versions of the proposed protocol in different environments and network conditions has been carried out via numerical simulations. The results state the suitability of the proposed protocol for small mobile cognitive radio ad hoc networks.