多模可重构终端的无线接入管理

本文给出了多模可重构终端(RT)的概念,并且设计了RT的基本功能结构模型,使其能够与各类异种无线接入网络(RANs)进行通信.文中针对RT如何选择RANs和无线接入技术(RATs)的问题,提出了一种具体的解决方案.该方案由终端和无线接入网络分工合作完成,终端方面是建立或者改变连接的发起方,负责与本地无线环境密切相关的信息处理,向网络传递用户需求等通信参数.文中通过RT接入管理的三层贝叶斯网络运算模型来实现上述功能.网络方面负责解决网络间合作的问题,拥有选择RANs和RATs的最终决策权.文中给出了网络方面为RT选择最佳RATs的流程图和算法.最后,仿真结果验证了上述方案的有效性.     

Intelligent framework for radio access network design

Wireless Networks - The evolution of 5G networks over the last few years has introduced a variety of technologies for more efficient radio access networks (RANs), which end up in ultra-dense...     

Evaluation of signalling loads in a cognitive network management architecture

Future networks will need to accommodate a significantly augmented user demand, mainly stemming from the wireless and mobile domains. In general, the emerging radio landscape will comprise multiple, collaborating radio access networks (RANs) able to operate a plethora of diverse radio access technologies (RATs), variant types of mobile terminals (MTs), with the ability to choose among various supported RANs/RATs and, in addition, both devices and networks with dynamic spectrum access capabilities that allow the sharing and/or optimization of spectrum usage among different systems. The above will stress network operators for developing mechanisms to confront the challenges and to leverage the opportunities posed by such a versatile radio environment. In particular, the situation calls for adaptive and flexible management paradigms that are able to dynamically manage network elements and terminals, thus ensuring the great availability and efficient usage of spectrum and other radio resources. Framed within the above, this paper considers a cognitive network management architecture, which is destined for optimized management of future wireless networks operating in versatile radio environments, and presents a performance evaluation methodology, which was set up for measuring the signalling loads that the operation of the architecture will bring to the managed network. The methodology is analytically described, and useful results with respect to the signalling load produced for management signalling purposes in an indicative scenario are presented and analysed. Copyright © 2011 John Wiley & Sons, Ltd.     

4G无线接入网拓扑结构展望

第四代移动通信(4G)系统的无线接入网如果沿用传统蜂窝结构,很难满足设计要求.为此文章介绍了可能用于4G系统的改进蜂窝结构,如光纤无线电(RoF)、分布式接收站、多跳无线接入蜂窝、簇-蜂窝,以及全新设计的非蜂窝结构,如Ad hoc和分布无线通信系统.在对这些结构进行了分析对比后,文章认为采用分布式处理/控制和多跳技术的无线接入网比传统蜂窝接入网更符合4G系统的要求.     

Inter-operator spectrum sharing scheme for reconfigurable system

Bargaining based mechanism for sharing spectrum between radio access networks (RANs) belonging to multioperators is studied, to improve spectrum utilization efficiency and maximize network revenue.By introducing an intelligent agent, each RAN has the ability, which includes trading information exchanging, final decision making, and so on, to trade the spectrum with other RANs.The proposed inter-operator spectrum sharing mechanism is modeled as an infinite-horizon bargaining game with incomplete information, and the resulting bargaining game has unique sequential equilibrium.Consequently, the implementation is refined based on the analysis.Simulation results show that the proposed mechanism outperforms the conventional fixed spectrum management (FSM) method in network revenue, spectrum efficiency, and call blocking rate.     

Diffserv extensions for QoS provisioning in IP mobility environments

We focus on DiffServ for QoS provisioning in radio access networks (RANs). We first give short explanations of the DiffServ model. We then investigate the problems of DiffServ under IP mobility environments. We also present several DiffServ proposals in IP-based access networks. We finally propose a mobility-aware drop precedence scheme for flows experiencing handover events.     

Middleware Architecture for Next Generation Heterogeneous Networks

In this paper we present a framework, called Futon, which provides a platform to integrate heterogeneous radio access networks. Futon is a hybrid fibre-radio network that replaces legacy base stations with simple remote antenna units, which are connected to a central unit. As a part of the Futon framework, a generic middleware architecture is discussed in detail, which provides interoperability, cooperative management and service provisioning to both underlying radio access networks (RANs) and IP layer for a heterogeneous network scenario. One of the middleware??s functionality is to provide vertical handover between heterogeneous IP-based radio access technologies and to ensure seamless mobility and service continuity, which is implemented on top of an IPv4/IPv6 Mobile IP (MIP) core. In this paper, the Futon framework and a generic middleware architecture as a part of Futon framework for heterogeneous RANs is discussed. The main modules of the middleware, namely common radio resource management (CRRM), media independent handover, Service/Connection Manager and link selection are explained in detail. Radio over fibre (RoF) Manager is an important part of Central unit, which does performance, fault and security management of network elements. RoF manager helps middleware during handoff, by providing the status of fibre optic links. The implementation of Security management module as a part of RoF manager, and results of authentication with AAA protocol are explained. The CRRM as part of middleware is simulated and the results of experimental evaluation are presented.     

异构无线系统中基于博弈的动态频谱管理

为提高频谱使用率并增加异构无线网络收益,用微观经济学的无限期轮流出价讨价还价博弈模型进行了异构网络间动态频谱管理的研究,提出了基于讨价还价理论的动态频谱管理(BDSM)方案。根据相关博弈理论,引入讨价还价耐心因子后BDSM存在唯一的均衡点。基于此,提出了实现BDSM方案的简化流程。仿真结果显示,BDSM能有效地提高频谱使用率、扩大单个运营商的利润并提高用户满意度。     

Genetic algorithm‐based content distribution strategy for F‐RAN architectures

Fog radio access network (F‐RAN) architectures provide markedly improved performance compared to conventional approaches. In this paper, an efficient genetic algorithm‐based content distribution scheme is proposed that improves the throughput and reduces the transmission delay of a F‐RAN. First, an F‐RAN system model is presented that includes a certain number of randomly distributed fog access points (F‐APs) that cache popular content from cloud and other sources. Second, the problem of efficient content distribution in F‐RANs is described. Third, the details of the proposed optimal genetic algorithm‐based content distribution scheme are presented. Finally, simulation results are presented that show the performance of the proposed algorithm rapidly approaches the optimal throughput. When compared with the performance of existing random and exhaustive algorithms, that of the proposed method is demonstrably superior.     

Throughput reliability analysis of cloud‐radio access networks

This paper develops a stochastic geometry‐based analytical approach for calculating the throughput reliability of a cloud‐radio access network (C‐RAN) comprising randomly distributed remote radio heads (RRHs) and randomly located users. A tunable distance‐based RRH transmit power control mechanism along with cooperative joint transmissions by the RRHs is employed to achieve power savings and high throughput reliability. The analytical result for the throughput reliability serves as input to analysis of per user achievable average rate and C‐RAN network‐level performance metrics of spectral efficiency and energy efficiency. The analytical results are validated by Monte Carlo simulation results with good agreement, thus confirming the accuracy of the developed analytical approach. The key finding from the analysis is that by carefully tuning the RRH transmit power and cooperation parameter (cluster radius), it is possible to realize a threefold improvement in the energy efficiency along with 108% enhancement in the spectral efficiency of C‐RANs. Copyright © 2016 John Wiley & Sons, Ltd.     

Connectivity, performance, and resiliency of IP-based CDMA radio access networks

IP-based radio access networks (RAN) are expected to be the next generation access networks in UMTS and CDMA networks. The question of connectivity, i.e., how best to connect base stations to the radio network controllers (RNC) in an IP-based RAN, has not been addressed by researchers. Furthermore, given a connection configuration, an RNC selection algorithm that assigns an incoming call to an RNC is also necessary. This paper examines RAN connectivity and its impact on the performance and resiliency of the wireless network using different RNC selection algorithms. For homogeneous networks, we show that the proposed min-load-1 algorithm, which allows at most one hard handoff in order to accommodate each incoming call request, delivers performance close to the optimal algorithm. We also show that allowing a few base stations to connect to two RNCs (a 10 percent increase in the number of links in our network) results in resiliency to RNC failures that is comparable to the resiliency of RANs with full-mesh connectivity. Finally, for heterogeneous networks, we show that the min-load-k algorithm (with at most k hard handoffs per call) is effective in handling load imbalances. These results provide strong motivation for deploying IP-based RAN, as they suggest that enhancing current point-to-point RAN with few additional links and allowing a few hard handoffs to accommodate incoming calls can result in significant gains in performance and resiliency.     

TOPSIS‐based approach for network slice selection in 5G mobile systems

Fifth‐generation (5G) mobile networks can be perceived as highly manageable systems that provide increased performance while supporting a variety of services with widely diverse requirements. Recently, network slicing has been proposed by academia and industry as a resource provisioning technique capable to meet these requirements with reduced operating costs while opening new horizons for network efficiency. The aim of network slice selection function (NSSF) is an optimal selection of network instances serving the users, based on local configuration, and other available information including radio access networks (RANs) performances in the registration area. In this paper, NSSF based on Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is proposed. Here, the network slices are treated as alternatives while their performance indicators are considered as the criteria for decision making. The influences of various alternative techniques, taking into account all the three stages of decision making process, that is, normalization, weighting, and ranking, are analyzed through the rank reversal phenomenon and computational complexity. Simulation results reveal that the proposed techniques can significantly improve the network slice selection procedure.     

Requirements and Algorithms for Cooperation of Heterogeneous Radio Access Networks

This paper defines the requirements for cooperation of heterogeneous radio access networks (RANs) and proposes a novel radio resource management (RRM) framework for support of mobility and quality of service (QoS) in a heterogeneous communication environment comprising IMT-Advanced and legacy systems. The reference IMT-Advanced system is the one developed within the IST project WINNER (IST-2003-507581 Project Wireless Initiative New Radio, ). The RRM mechanisms are evolved from traditional ones to comply with the requirements imposed by a simplified new (RAN) architecture as proposed for IMT-Advanced systems. The RRM mechanisms are evaluated for the scenario of intra-RAN and inter-RAN user mobility. The RRM framework incorporates as novelty improved triggering mechanisms, a network-controlled mobility management scheme with policy enforcement on different levels in the RAN architecture, and a distributed handover and admission control mechanism for fast decision polling at different levels of the RAN. The RRM framework is further enhanced with computational intelligence based on fuzzy logic algorithms to enhance the process of handover. The RRM framework has been evaluated in terms of reduced user blocking probabilities.

Internetworking of Multiwavelength Local Optical Networks Based on a Wavelength-Tolerant Receiver Technology*

Robust-WDM is a technique to realize wavelength division multiplexed (WDM) local area networks (LANs) in the presence of laser wavelength drifts. Various medium access control (MAC) protocols have been proposed for Robust-WDM LANs. Among these protocols, the one with Aperiodic Reservation and Lenient Token-Passing control channel (the AR/LTP protocol) is the most promising. We discuss three internetworking strategies for AR/LTP Robust-WDM LANs. The aim is to explore the possibility to scale the AR/LTP Robust-WDM concepts to the metropolitan domain by looking at some basic medium-access arrangements and specifying the advantages and limitations of each. Special Remote Access Nodes (RANs) are proposed to facilitate interconnection. It is shown that by some modifications in the basic AR/LTP local area protocol and by parallel processing of connection requests, commands and control signals, the waiting time performance of a Robust-WDM interconnection can be improved. The improvement would be accomplished at the expense of some control sophistication. Further improvement can be achieved by designing a set of point-to-point links among the RANs of different Robust-WDM stars. In this case, control is relatively simplified, but the design of a RAN is made more complex and expensive.     

泛在无线环境中多无线接入网协同的业务分配策略

This paper introduces an adaptive traffic allocation scheme with cooperation of multiple Radio Access Networks (RANs) in universal wireless environments. The different cooperation scenarios are studied, and based on the scenario of cooperation in both network layer and terminal layer, an open queuing system model, which is aiming to depict the characteristics of packet loss rate of wireless communication networks, is proposed to optimize the traffic allocation results. The analysis and numerical simulations indicate that the proposed scheme achieves internetworking load balance to minimize the whole transmission delay and expands the communication ability of single-mode terminals to support high data rate traffics.     

Joint resource optimization for nonorthogonal multiple access-enhanced scalable video coding multicast in unmanned aerial vehicle-assisted radio-access networks

A joint resource-optimization scheme is investigated for nonorthogonal multiple access (NOMA)-enhanced scalable video coding (SVC) multicast in unmanned aerial vehicle (UAV)-assisted radio-access networks (RANs). This scheme allows a ground base station and UAVs to simultaneously multicast successive video layers in SVC with successive interference cancellation in NOMA. A video quality-maximization problem is formulated as a mixed-integer nonlinear programming problem to determine the UAV deployment and association, RAN spectrum allocation for multicast groups, and UAV transmit power. The optimization problem is decoupled into the UAV deployment–association, spectrum-partition, and UAV transmit-power–control subproblems. A heuristic strategy is designed to determine the UAV deployment and association patterns. An upgraded knapsack algorithm is developed to solve spectrum partition, followed by fast UAV power fine-tuning to further boost the performance. The simulation results confirm that the proposed scheme improves the average peak signal-to-noise ratio, aggregate video-reception rate, and spectrum utilization over various baselines.     

常见的无线电干扰及其规避措施探讨

无线电干扰查处工作,是无线电管理工作中的一项重要的任务,作为无线电管理工作者对监测设备的工作原理、功能、技术性能、指标要深刻领会理解,要求掌握电磁环境随地形、频率、天气、距离等外部条件的变化规律。掌握各类干扰的成因及其规避措施,是有效降低无线电干扰发生率的主要途径。如何科学有效地规避频率间的干扰,介绍常见的无线电干扰类型、特征、危害性及其抑制干扰采取的措施。     

GSM与GPRS无线网络协调优化分析

GPRS无线网络以GSM无线网络作为其承载网,这决定了GPRS网络优化具有与GSM网络优化相互关联、相互制约的特点.本文介绍GPRS无线网络优化的主要流程和内容,综合考虑对现有GSM无线网络的影响,合理利用现有无线网资源,以效益最大化为目标,实现两个网络的优化平衡.     

网络技术在广播电视工程中的应用

随着网络技术的不断发展和普及,广播电视工程领域也在逐步应用网络技术,以提高广播电视行业的效率和服务质量。文中论述了网络技术与广播电视工程的联系、网络技术在广播电视传输中的应用、网络技术在广播电视制作中的应用、网络技术在广播电视服务中的应用以及网络技术在广播电视工程中的未来应用方向,旨在全面探讨网络技术在广播电视工程中的应用情况,为广播电视工程的发展提供参考。     

新的无线通信技术：软件无线通信

无线通信技术近年来有了飞快的发展，正从第一代的模拟无线通信迈向第二代数字无线通信，现在新一代无线通信技术：软件无线通信正在兴起。本文就什么是软件无线通信？它的主要特点是什么？它和数字无线通信有何区别？有何优越性？等问题作了一些介绍。