Adaptive Energy Detection Based Solution for Fronthaul Problem in C-RAN

It hasbeen anticipated that the fifth generation (5G) wireless systems will deliver an efficient growth of the energy and spectral efficiency. To accomplish these goals, centralized radio access networks (C-RAN) is presented as the advanced wireless access networks paradigm with centralized baseband units (BBUs) and remote radio heads (RRHs). Although it is affected by Common Public Radio Interface (CPRI) limitations which requires high bandwidth for existing BBU/RRH interfaces. Moreover, the fronthaul links the BBU and RRH. But CPRI limits the deployment of C-RAN for fronthaul networking due to its fixed-rate fronthaul interface which transmit CPRI streams even in the absence of traffic load. However, this causes data transmission inefficient. So, the classical fronthauling method demands high bandwidth and the failure of fronthaul will cause losing a very high bandwidth. The purpose of this paper is to develop energy detection (ED) based algorithm which permits the secondary users to use the channel without interfering the primary users, so that the bandwidth in the fronthaul can be used in an efficient manner. A dynamic threshold with noise uncertainty based ED algorithm is proposed in this paper. It compares the fixed threshold with dynamic threshold by comparing probability of detection with probability of false alarm. Finally, by using this proposed algorithm, it can be concluded that performance of the probability of detection improves even with the presence of noise uncertainty.     

A virtualized resource management scheme for heterogeneous cellular networks

Because of random deployment patterns of femtocells, interference scenarios in a heterogeneous cellular network can be very complicated because of its changing network topology. Especially when each eNodeB occupies a fixed bandwidth, interference management becomes much more difficult. The benefit of dynamic management for local resource optimation is limited. Recently, resource virtualization has been proposed as a dynamic resource management scheme to optimize network performance. In fact, resource virtualization is viewed as a more flexible model, in which mobile network service providers can control physical resources in a global scope. This paper presents a joint resource virtualization and allocation scheme for its applications in heterogeneous macro‐femto‐cellular networks. The proposed scheme involves two major processes. First, it virtualizes physical resources as logical resources. Second, it carries out logical resource allocation optimization globally and aggregates logical and physical resources for resource allocation. The proposed scheme takes into account spectrum reuse and frequency domain interference jointly in order to achieve a high spectral efficiency and provide rate‐on‐demand services to all users. Simulation results demonstrate the effectiveness of the proposed scheme. Copyright © 2016 John Wiley & Sons, Ltd.     

虚拟网络功能资源容量自适应调整方法

为了实现网络功能虚拟化平台中物理资源的动态按需分配,该文提出一种虚拟网络功能资源容量自适应调整方法。该方法首先利用长短期记忆网络预测平台流量的变化趋势,然后结合流量预测结果设计了一种基于多层前馈神经网络的虚拟网络功能资源需求预测方法,最后根据资源需求预测结果,设计了一种基于动态编码遗传算法的虚拟网络功能动态部署方法,实现虚拟网络功能资源容量的自适应调整。实验结果表明,与现有的资源容量调整方法相比,该文提出的资源容量自适应调整方法能够降低流量预测误差对资源需求预测结果的影响,降低资源需求预测的相对误差,减少虚拟网络功能实例占用的服务器数量。     

基于改进遗传算法的C-RAN网络动态无线资源分配

针对云无线网络(Cloud Radio Access Network,C-RAN)中传统静态资源分配效率低下以及动态无线资源分配中资源种类单一的问题,提出了一种基于用户服务质量(Qulity of Service,QoS)约束的动态无线资源分配方案,对无线资源从无线射频单元(Remote Radio Head,RRH)选择、子载波分配和RRH功率分配三个维度进行研究.首先,根据传统的C-RAN系统传输模型和QoS约束在时变业务环境下建立了以发射功率为变量,以吞吐量最大为优化目标的优化问题;然后,基于改进的遗传算法,将原优化方案转变为通过优化RRH选择、子载波分配和RRH功率分配来达到提高系统吞吐量的目的;最后,将改进的遗传算法与其他智能算法在种群规模变化下进行了时间复杂度对比.实验结果表明,所提算法具有较低时间复杂度,所提资源分配方案下的平均吞吐量增益为17％.     

基于非正交多址接入的网络切片联合用户关联和功率分配算法

为了满足网络切片多样化需求,实现无线虚拟资源的动态分配,该文提出在C-RAN架构中基于非正交多址接入的联合用户关联和功率资源分配算法。首先,该算法考虑在不完美信道条件下,以切片和用户最小速率需求及时延QoS要求、系统中断概率、前传容量为约束,建立在C-RAN场景中最大化长时平均网络切片总吞吐量的联合用户关联和功率分配模型。其次,将概率混合优化问题转换为非概率优化问题,并利用Lyapunov优化理论设计一种基于当前时隙的联合用户调度和功率分配的算法。最后采用贪婪算法求得用户关联问题次优解;基于用户关联的策略,将功率分配的问题利用连续凸逼近方法将其转换为凸优化问题并采用拉格朗日对偶分解方法获得功率分配策略。仿真结果表明,该算法能满足各网络切片和用户需求的同时有效提升系统时间平均切片总吞吐量。     

Physical layer security strategies for downlink heterogeneous cloud radio access networks

Cloud radio access networks （C-RANs） were proposed as promising solutions to increase both spectrum and energy efficiency performance in next generation wireless communication systems. Much works discussed the concrete implementation technology to justify the huge development potential of C-RAN. However, only a few litterateurs focused on characterizing the physical layer security in the downlink. The authors studied the physical layer security in downlink heterogeneous C-RAN systems in the article. To characterize the random deployment of remote radio units （RRUs） with single antenna configuration, the stochastic geometry is based to evaluate the proposals＇ secrecy transmission capacity performances, where the closed-form expressions are derived. Furthermore, two security strategies based on eavesdropper neutralization region to protect the target RRU user against eavesdropping were presented and analyzed. Simulation illustrates the secrecy transmission capacity performance limits on different system parameters. The presented security strategies show a significant enhancement on the secrecy performance.     

An Elastic Sub-carrier and Power Allocation Algorithm Enabling Wireless Network Virtualization

Wireless mobile network virtualization enables physical mobile network operators (PMNO) to partition their network resources into smaller slices and assign each slice to an individual virtual mobile network operator and then manages these virtual networks in a more dynamic and cost-effective fashion. How a PMNO allocates resources to individual slices while ensuring resource elasticity is a key issue. This paper presents a resource allocation algorithm in such a network virtualization scenario where resource considered here includes both sub-carriers and transmission power. The overall algorithm involves the following two major processes: firstly to virtualize a physical wireless network into multiple slices each representing a virtual network, where resources are allocated elastically based on traffic loads and channel state information during virtualization; secondly, to carry out physical resource allocation within each virtual network (or slice). In particular the paper adopts orthogonal frequency division multiplexing as its physical layer to achieve more efficient resource utilization. A multi-step dynamic optimization approach is proposed to achieve sub-carrier allocation using binary integer programming and power allocation using nonlinear programming. The aim is to achieve the following design goals: virtual network isolation, and resource efficiency. The simulation results show that the above goals have been achieved.     

C-RAN：面向绿色的未来无线接入网演进

 在高速发展的移动业务和日趋激烈的竞争环境下,移动运营商面临着多方面的挑战：高额的能耗、高涨的建设和运维成本、紧张的频谱资源、快速增长的业务流量以及日趋严峻的成本压力。为解决这些挑战并追求未来可持续的增长,根据现网条件和技术进步的趋势,提出了面向绿色演进的新型无线接入网构架C-RAN。C-RAN是基于集中化处理(Centralized),协作式无线电(Cooperative Radio)和实时云计算构架(Real-time Cloud Infrastructure)的无线接入网构架, 集中式基带处理可以大大减少覆盖同样区域所需基站的数量;面向协作的无线远端模块和天线可以提高系统频谱效率;基于开放平台的实时云型基础设施和基站虚拟化技术可以降低成本,共享处理资源,减少能源消耗,提高基础设施利用率。这些特点能够很好地解决移动运营商所面临的上述挑战,并满足营收和未来移动互联网业务同步发展要求。     

An elastic resource allocation algorithm enabling wireless network virtualization

Following the wired network virtualization, virtualization of wireless networks becomes the next step aiming to provide network or infrastructure providers with the ability to manage and control their networks in a more dynamic fashion. The benefit of the wireless mobile network virtualization is a more agile business model where virtual mobile network operators (MNOs) can request and thus pay physical MNOs in a more pay‐as‐you‐use manner. This paper presents some resource allocation algorithms for joint network virtualization and resource allocation of wireless networks. The overall algorithm involves the following two major processes: firstly, to virtualize a physical wireless network into multiple slices, each representing a virtual network, and secondly, to carry out physical resource allocation within each virtual network (or slice). In particular, the paper adopts orthogonal frequency division multiplexing (OFDM) as its physical layer to achieve more efficient resource utilization. Therefore, the resource allocation is conducted in terms of sub‐carriers. Although the motivation and algorithm design are based on IEEE 802.16 or WiMAX networks, the principle and algorithmic essence are also applicable to other OFDM access‐based wireless networks. The aim was to achieve the following design goals: virtual network isolation and resource efficiency. The latter is measured in terms of network throughput and packet delivery ratio. The simulation results show that the aforementioned goals have been achieved. Copyright © 2012 John Wiley & Sons, Ltd.     

Experimental validation of resource allocation in transport network slicing using the ADRENALINE testbed

Transport network virtualization provides the necessary data and control plane technologies as key enablers of future networks. The interaction between network slicing and optical transport network virtualization architectures is under study to automate effective network resource orchestration. In this paper, we present an harmonized network slicing and transport network virtualization architecture, including a network slice planner tool, which is designed and implemented enabling in-operation execution of network slice resource allocation algorithms. We validate the proposed architecture by providing a novel resource allocation algorithm, evaluating its performance and deploying two different slices on top of the ADRENALINE testbed, while measuring both slices key performance indicators.

     

异构无线网络资源管理与切换控制技术

随着通信技术的发展,新型业务逐渐增多,传统的通信网络无法满足各种业务之间巨大的性能需求差异,未来的通信网络逐渐向异构网络进行发展。针对异构网络中资源调配与垂直切换的问题,利用虚拟网络技术与资源虚拟化技术设计了异构网络中的无线资源管理方法,并设计了子网间垂直切换算法。该算法利用层次分析法与熵权法得到各网络参数的综合权值,加权得到各网络的效用值并依此选择最优网络。通过搭建系统平台验证了设计的异构无线网络的有效性,为后续异构无线网络的研究提供了参考。     

虚拟化云无线接入网络下基于在线学习的网络切片虚拟资源分配算法

针对现有研究中缺乏云无线接入网络(C-RAN)场景下对网络切片高效的动态资源分配方案的问题,该文提出一种虚拟化C-RAN网络下的网络切片虚拟资源分配算法。首先基于受限马尔可夫决策过程(CMDP)理论建立了一个虚拟化C-RAN场景下的随机优化模型,该模型以最大化平均切片和速率为目标,同时受限于各切片平均时延约束以及网络平均回传链路带宽消耗约束。其次,为了克服CMDP优化问题中难以准确掌握系统状态转移概率的问题,引入决策后状态(PDS)的概念,将其作为一种“中间状态”描述系统在已知动态发生后,但在未知动态发生前所处的状态,其包含了所有与系统状态转移有关的已知信息。最后,提出一种基于在线学习的网络切片虚拟资源分配算法,其在每个离散的资源调度时隙内会根据当前系统状态为每个网络切片分配合适的资源块数量以及缓存资源。仿真结果表明,该算法能有效地满足各切片的服务质量(QoS)需求,降低网络回传链路带宽消耗的压力并同时提升系统吞吐量。     

A Novel Immune Optimization Algorithm for Fairness Resource Allocation in Cognitive Wireless Network

Cognitive wireless network (CWN) is a novel concept for improving the utilization of scarce wireless spectrum resources. Dynamic resource allocation is an important task in such systems. In this paper, a novel resource allocation algorithm for multi-user OFDM-based CWN is presented. It is formulated into a constraint problem, and an optimization algorithm based on novel immune clonal is proposed. The proposed algorithm fully takes into account the maximum tolerable interferences of primary user and the proportional fairness for secondary user. The suitable operators for solving the problem are designed, such as clonal, mutation, Baldwin learning, selection and so on. The simulation results show that the proposed algorithm achieves high system throughput with proportional fairness among the secondary users.     

Towards efficient dynamic surface gateway deployment for underwater network

In underwater acoustic sensor network, deploying multiple surface-level radio capable gateways is an efficient way to alleviate the burdens of high propagation delay and high error probability during transmission. However, the locations of gateways need to be carefully selected to maximize the benefit in a cost-effective way. In this paper, we present our formulation of the surface gateway deployment problem as an integer linear programming (ILP) and we solve the problem with heuristic approaches to provide a realtime solution for large scale deployment problems. By applying the proposed heuristic algorithms to a variety of deployment scenarios, we show that they are nearly optimal for practical cases, which opens the door for dynamic deployment. Therefore, we extend our solution to a dynamic case and propose a modified framework that integrates Aqua-sim, a NS2-based underwater wireless sensor network simulator. Our simulation result shows the benefits of dynamic gateway redeployment over static deployment.     

能耗和时延感知的虚拟化云无线接入网络资源分配机制

针对现有虚拟化云无线接入网络(C-RAN)资源利用率低、能耗高、用户服务质量无法得到保证等问题,该文提出一种能耗和时延感知的虚拟化资源分配机制。根据虚拟化C-RAN的网络特点及业务流量特征,考虑资源约束和比例公平,建立能耗和时延优化模型。进而,利用启发式算法为不同类型虚拟C-RAN和用户虚拟基站分配资源,完成资源的全局优化配置。仿真结果表明,所提资源分配机制在提高网络资源利用率的同时,不但使能耗节省了62.99%,还使时延降低了32.32%。     

时分波分无源光网络与云无线接入网联合架构中负载平衡的用户关联与资源分配策略

在时分波分无源光网络(TWDM-PON)与云无线接入网(C-RAN)的联合架构中,由于无线域的负载不均衡问题,限制了网络整体的传输效率。为了充分利用TWDM-PON与C-RAN联合架构的网络资源,并保证用户的服务质量(QoS),该文提出一种负载平衡的用户关联与资源分配算法(LBUARA)。首先根据不同用户的服务质量需求以及分布式无线射频头端(RRH)的负载对用户的影响,构建用户收益函数。进而,在保证用户服务质量的前提下,根据网络状态建立随机博弈模型,并基于多智能体Q学习提出负载均衡的用户关联和资源分配算法,从而获得最优的用户关联与资源分配方案。仿真结果表明,所提的用户关联和资源分配策略能够实现网络的负载均衡,保证用户的服务质量,并提高网络吞吐量。     

MIMO Based Radio Resource Management for UMTS Multicast Broadcast Multimedia Services

MIMO systems promise high performance gains over conventional single antenna systems. To accomplish high data rates over wireless links the use of multiple transmit and receive antennas is an alternative that does not require any extra bandwidth. It has the potential to address the unprecedented demand for wireless services, particularly for the Multimedia Broadcast Multicast Service (MBMS). This service supports downlink streaming and download-and-play type services to large groups of users. From the radio perspective, MBMS includes point-to-point (PtP) and point-to-multipoint (PtM) modes. New proposed MBMS related enhancements in the physical layer specifications and their effects on resource requirements are presented in this paper, such as the use of High Speed Downlink Packet Access (HSDPA) to broadcast/multicast video streaming using the Deficit Round Robin (DRR) scheduler algorithm as a way to maintain an acceptable QoS for all the users. Other improvements, based on the use of MIMO including macro-diversity, are independent of the mode used and are dependent on deployment scenarios, but can yield substantial reduction in resource demand.     

Radio resource management in wireless LANs

Some chief information officers and information technology managers are reluctant to deploy wireless LANs. Among their concerns are reliability, availability, performance, and deployment. Each of these concerns can be directly addressed through the radio resource management techniques used in a new generation of wireless LAN equipment. The new capabilities include dynamic channel assignment, dynamic power control, and load sharing. Changing from the relatively static radio resource management techniques generally in use today to dynamic methods like those highlighted in this article helps to increase the capacity and improve the performance of large-scale wireless LANs.     

基于固件虚拟的承载网络资源重构模型研究

结合三网融合的异构网络环境,提出了一种基于固件虚拟的承载网络资源重构模型,并对异构环境下动态可重构网络的关键技术——资源分配算法进行研究,提出了一种基于动态重构的资源分配算法.该模型基于平台化支撑、构件化处理的思想,设计基于底层承载网络中核心节点虚拟化的可重构网络,支持异构网络环境下的动态重构,从而构建更为灵活的高速率、可定制、多服务提供网络.     

Dynamic process location management in 5G

5G, as the next generation of wireless networks, promises very high throughput and low latency to mobile users that calls for a substantial innovation in computing management platforms to attend QoS metrics. Thanks to emerging technologies such as software‐defined networking (SDN)/network function virtualization (NFV), many features are available in 5G design to detect and control two types of latency caused by computation and communication. In this paper, taking features of caching mechanisms and SDN into the account, a platform is proposed to minimize latency in 5G via caching big flows intelligently and avoiding bottlenecks that may cause by virtualized computing components. First, the pioneering idea of compromising between the cloud radio access network (CRAN) and mobile edge computing (MEC)/information‐centric network (ICN) via dynamic processing location management platform is investigated. Accordingly, a mathematical optimization problem to minimize the average latency is formulated. Due to the problem complexity, a heuristic algorithm is proposed to treat the latency via dynamic orchestration of processing functionalities. Through numerical results, the performance of the proposed algorithm is analyzed, and the simulations corroborate our analytical results and illustrate the superior performance of the proposed algorithm with acceptable optimality gap.