Optimal joint utility based load balancing algorithm for heterogeneous wireless networks

The rapid development of mobile broadband services with continuously increasing traffic volumes has resulted in a number of challenges, including ubiquitous network coverage, high bandwidth, and reliable services for reasonable price, etc. To address these challenges, evolved packet system (EPS) is proposed as the evolution of the packet core network. While resource management and load balancing issues in EPS are discussed in 3GPP standardization, relatively few research works consider mechanism design for load information monitoring and evaluation. Furthermore, even though some load balancing algorithms have been proposed for integrated networks, the load balancing scheme design which achieves the optimization of joint system performance has not been extensively studied. In this paper, an inter-access system anchor based load balancing mechanism is introduced which performs load monitoring and evaluation for access gateways and networks, and an optimal load balancing algorithm is proposed for heterogeneous integrated networks. To characterize the performance of integrated networks, the concept of utility function is introduced and the comprehensive performance of integrated networks which support both single type service and multimedia service is modeled mathematically. Applying vertical handoff as an efficient mechanism for achieving load balancing, the optimal number of handoff users is obtained through solving the optimization problem. Numerical results demonstrate that load balancing between access networks can be achieved, and the optimal number of handoff users corresponding to the maximal joint network utility can be obtained.     

基于软交换的网络智能化方案

电信固网运营商的网优网改、无线市话（PHS）网络与公共交换电话网（PSTN）等网络的融合、通信网络宽带化和多媒体化、PSTN网络与第3代移动通信（3G）网络融合等催生了固网网络智能化的需求。通过软交换技术来满足这一需求是切实可行的方法。基于软交换的网络智能化解决方案丰富了通信业务，促进了固网和移动网的融合，是极具优势的网络智能化方案。     

LTE网络中多目标优化的动态负载均衡算法

小区间动态负载均衡算法的优劣对网络性能有很大的影响,现有算法大都顾此失彼,难以保证网络关键性能指标(如呼叫阻塞率等)达到最佳。为解决这个问题,该文将负载均衡问题建模为多目标优化问题,分别对不同服务质量要求用户建模其相应目标优化函数,对有服务质量要求用户的目标函数是负载均衡指示函数和网络平均负载函数的联合优化函数,而对没有服务质量要求用户(BE用户)的目标函数是所有BE用户吞吐量的总效用函数,并将小区可用资源数和用户服务质量要求作为约束条件。另外,考虑到在实际系统中运行的计算复杂度问题,提出一种复杂度较低的分布式负载均衡算法。包括资源调度策略,用户切换条件和呼叫接入控制。仿真结果表明,该文算法可达到较好的负载均衡效果,能有效降低有服务质量要求用户的呼叫阻塞率,提高网络资源利用率。     

Load balancing and its performance evaluation for layer 3 and IEEE 802.21 frameworks in PMIPv6‐based wireless networks

Mobile IP (MIP) requires mobile nodes (MNs) to register with the home agents (HAs) whenever the MNs change their point of attachment (PoA: access point (AP) or base station (BS)) in different subnets. Thus, such registrations cause excessive signaling overhead and long service delay. To solve this problem, proxy mobile IPv6 (PMIPv6) has been proposed by the IETF NETLMM working group. In PMIPv6, a new entity called mobile access gateway (MAG) performs the mobility‐related signaling with the local mobility anchor (LMA) on behalf of the MN and establishes a tunnel with the LMA. However, a number of MNs must be associated with an MAG, which means that the MAG can be easily overloaded. Therefore, in this paper, we propose a load balancing mechanism among the MAGs in the PMIPv6 network. The PMIPv6 handover signaling procedure is extended to support the proposed load balancing mechanism. We also discuss using IEEE 802.21 Media Independent Handover (MIH) protocol for load balancing to determine the load status at the candidate PoAs, in addition to the load status at the candidate MAGs. To evaluate the performance, we analyze the average waiting time in the queue at the MAG. Through simulations and numerical analysis, we show that the proposed load balancing mechanism can produce less queueing delay at the MAG and a higher data transmission rate at the PoA than when a load balancing operation is not performed in the PMIPv6 network. Copyright © 2009 John Wiley & Sons, Ltd.     

An access-aware pricing strategy for the evolved packet system

The evolved packet system (EPS) integrates third generation partnership project (3GPP) and non-3GPP wireless access networks to provide mobile users with ubiquitous access to a diverse set of multimedia services. As we know, 3GPP and non-3GPP access networks differ significantly with respect to bandwidth capacity, coverage range, and service cost. It is crucial to enable efficient load balancing between 3GPP and non-3GPP access networks to improve resource utilization, and still maximize revenue generation. From an economic point of view, pricing plays an important role in achieving load balancing in the EPS. This paper proposes an access-aware pricing strategy for the EPS to achieve load balancing between 3GPP and non-3GPP access networks and to maximize revenue generation for network operators. In addition, this paper develops an analytical model for the system using the proposed access-aware pricing strategy. With the analytical model, this paper also proposes an iterative method for determining the optimal pricing that maximizes revenue generation in the EPS. The analytical model is verified by simulation.     

Reliability and Mobility Load Balancing in Next Generation Self-organized Networks: Using Stochastic Learning Automata

Self-organizing networking (SON) is an automation technology designed to make the planning, configuration, management, optimization and healing of mobile radio access networks simpler and faster. Most current self-organization networking functions apply rule-based recommended systems to control network resources which seem too complicated and time-consuming to design in practical conditions. This research proposes a cognitive cellular network empowered by an efficient self-organization networking approach which enables SON functions to separately learn and find the best configuration setting. An effective learning approach is proposed for the functions of the cognitive cellular network, which exhibits how the framework is mapped to SON functions. One of the main functions applied in this framework is mobility load balancing. In this paper, a novel Stochastic Learning Automata has been suggested as the load balancing function in which approximately the same quality level is provided for each subscriber. This framework can also be effectively extended to cloud-based systems, where adaptive approaches are needed due to unpredictability of total accessible resources, considering cooperative nature of cloud environments. The results demonstrate that the function of mobility robustness optimization not only learns to optimize HO performance, but also it learns how to distribute excess load throughout the network. The experimental results demonstrate that the proposed scheme minimizes the number of unsatisfied subscribers (N_us) by moving some of the edge users served by overloaded cells towards one or more adjacent target cells. This solution can also guarantee a more balanced network using cell load sharing approach in addition to increase cell throughput outperform the current schemes.

     

移动Sink传感网中基于IEEE 802.15.4的拓扑控制与路由

针对查询驱动的移动Sink无线传感器网络,基于IEEE 802.15.4标准,提出了一个联合簇树组网和移动路由的跨层协议设计方案。以能耗、网络连通度、负载均衡和子树深度等指标为评价因子,在多目标优化模型下定义了一个拓扑综合评价函数,构建稳定的最优簇树网络结构;改进了IEEE 802.15.4 MAC中基于信标帧调度的分布式睡眠同步算法,维护较低占空比下的网络同步与拓扑修正;利用拓扑形成过程中依"最早信标帧"、"最好链路"、"最小层次"3种准则确立的父子关系,建立移动Sink与N-Hop范围内节点的双向路由路径。最终将上述MAC层的拓扑控制方案与网络层的查询路由方法完整实现于TinyOS协议栈中。实验结果表明,评价函数能够有效地反映组网质量,N-Hop后验式路由结合睡眠同步机制,在"最好链路"拓扑下表现出较高的能量效率。     

A distributed implementation of mobility load balancing with power control and cell reselection in 4G network

We consider a self‐organizing network (SON) capability of mobility load balancing in a 4G network, which determines the transmission power level for individual base stations and cell reselection for individual mobile stations such that the network‐wide load is minimized while satisfying the minimum signal‐to‐noise and interference ratio (SINR) requirement of individual users. Both centralized and distributed schemes are proposed. The centralized scheme is based on the greedy algorithm, serving as a performance bound to the distributed scheme. The distributed scheme is to solve the system‐wide optimization problem in the flat network model, i.e. no central control node. Furthermore, it requires relatively low inter‐cell exchange information among neighboring cells over an inter‐cell channel, e.g. X2 interface in the LTE network. The proposed design objective is to minimize the number of mobile users that do not satisfy the specified average throughput, while distributing the user traffic load as uniformly as possible among the neighboring cells. Our simulation results for a uniform user distribution demonstrate that the proposed scheme can achieve up to almost 80% of a load balancing gain that has been achieved by a greedy algorithm in the centralized optimization. Copyright © 2014 John Wiley & Sons, Ltd.     

Dynamic inter-domain MDS approach with secure seamless handover based on IEEE 802.21 MIH

The accessibility of available wireless access technologies with increasing demand for real time multimedia application becomes an essential part for mobile communication. Mobile users resourcefully utilize the heterogeneous environment for best quality of service (Qos) anywhere and anytime. Efficient handover optimization and intelligent mobility management is a key requirement for designing next generation wireless networks. Therefore, a novel IEEE 802.21 media independent handover (MIH) standard is adopted to provide an associated service for intelligent handover procedures. In addition, dynamic mobility management decision server (MDS) and IEEE 802.21a security extension for MIH services are also integrated in the proposed architectures to support fast, seamless and secure handover optimization in inter-domain mobility. Simulation results prove that the presented work resourcefully minimizes the packet loss, unnecessary handover probability and vertical handover delay by avoiding time consuming scanning process for target network discovery. The system thus achieves Qos guarantee by balancing the network load and throughput improvement for different applications with Proxy MIPv6 mobility management protocol.     

移动软交换中越区切换实现研究

软交换是下一代网络控制层中的核心实体,越区切换是移动软交换的重要功能之一。该文分析了越区切换的功能特点,研究了移动软交换中越区切换与呼叫控制和接入协议的关系。对越区切换进行了功能分解和分析,提出了一种可扩展性强、易于向3G演进的越区切换模块构建方式和越区切换状态机的实现方法。     

WLAN_MESH中一种基于负载均衡的接入点选择方法

针对WLAN Mesh网络进行接入点选择方法设计时,传统的接入方法以RSSI强度作为接入判断准则存在的缺陷问题,本文提出一种基于负载均衡的接入点选择方法,通过在负载均衡器中添加负载控制模块对网络和节点的负载进行实时监控,并建立网络效用模型,确定联合网络收益最大所对应的每个网络的接入用户数量,使得网络之间负载均衡且联合收益最大化。     

Active overload prevention based adaptive MAP selection in HMIPv6 networks

Multi-level mobile anchor points (MAP) architecture is deployed in large-scale wireless/mobile networks using HMIPv6 to achieve better mobility service, while selecting the most suitable serving MAP for the mobile nodes (MNs) to enhance the whole network performance has been a critical issue. An adaptive MAP selection based on active overload prevention (MAP-AOP) hence is proposed. The MAP periodically evaluates the load status by using dynamic weighted load evaluation algorithm, and then sends the load information to the covered access routers (AR) by using the expanded routing advertisement message in a dynamic manner. Taking achieving the load balancing among the available MAPs, the current serving AR executes the active overload prevention to select MAP candidates for the MN pending a handover, and then adaptively selects an optimal one from the candidates by comprehensively considering the system cost and the average handover latency caused by each candidate. The simulation conducted on the NS-2 platform indicates that MAP-AOP outperforms the comparative MAP selection schemes with the optimized system cost and average handover latency, and better load balancing.     

Multicasting streaming media to mobile users

Content distribution in general, and multicasting in particular, over a wired network to static hosts can be realized by placing proxies and gateways at several parts of the network. However, if the end hosts are mobile over heterogeneous wireless access networks, one needs to consider many operational issues such as network detection, handoff, join and leave latency, and desired level of quality of service, as well as caching and load balancing. This article surveys a set of protocols and technologies that offer multicast-based services for streaming multimedia in a mobile environment. It also brings forth some of the issues related to mobile content distribution in the wireless Internet that may be helpful during its deployment by application service providers.     

基于离散多目标优化粒子群算法的多移动代理协作规划

无线传感器网络中多移动代理协作能快速高效地完成感知数据汇聚任务,但是随着移动代理访问数据源节点数的增加,移动代理携带的数据分组会逐渐增大,导致传感器节点能量负载不均衡,部分数据源节点能耗过快,网络生存期缩短。目前,针对该问题所设计的能耗均衡算法,多以降低多移动代理总能耗为目标,却未充分考虑部分数据源节点能量消耗过快对网络生存期造成的影响。提出离散多目标优化粒子群算法,以网络的总能耗和移动代理负载均衡作为适应度函数,在多移动代理协作路径规划中寻求近似最优解。通过仿真实验验证,所提出的多移动代理协作路径规划,在网络总能耗和网络生存期方面的性能优于同类其他算法。     

基于FAHP的hadoop平台移动终端云存储优化研究

Hadoop云存储架构的设计初衷是实现大文件的高效存储处理,但在处理移动终端下诸如图片等小文件时会引起名称节点索引提取速度过慢和数据节点存储空间利用率不高等问题.针对这一问题,提出一种小文件归档的方案FHAR.方案综合考虑移动终端用户访问的实时性、名称节点服务器内存使用率、数据节点存储空间利用率等方面,利用双层索引的归档技术结合FAHP（模糊多属性决策理论）的系统负载预测算法实现系统的负载均衡,提高服务效率.同时利用数据预取机制对访问操作进行优化.仿真结果表明,该方案有效提高了节点的存储效率与用户访问的实时体验性.     

IP承载网单平面丢包问题的组网优化

针对移动软交换Mc接口组网中IP承载网单平面丢包问题,分析其在主备接入方式、负荷分担接入方式下对软交换业务的影响,并重点分析了负荷分担接入方式下的相关优化思路,提出了具体的组网优化建议,对移动软交换组网优化及网络安全有一定的参考意义。     

LTE网络多载波自动化智能均衡研究

网络负荷的增加,传统依靠人工调整负荷均衡已不能满足优化需求。自动化智能均衡方案通过穷举影响相邻两个小区覆盖性能的天馈、功率、互操作等类别参数,并进行归一化分析,自动输出负荷均衡调整方案。对无法通过覆盖均衡实现负荷均衡的小区,通过引入迭代算法,在优化边界范围内以固定步长自动输出负荷均衡调整建议,这有利于提高LTE网络容量、提高网络资源利用率、也有利于降低传输时延、降低人工和时间成本。     

Design and operation of energy efficient heterogeneous mobile networks

During the last two decades we have witnessed a rapid growth in wireless communication services, which has dramatically increased the number of necessary radio access components to provide the adequate capacity and acceptable quality of service. The power cost for operating this huge number of radio Base Stations (BSs) is under serious consideration by the mobile communication industry and recent research efforts have focused on energy efficient design and optimization of the radio access network in order to alleviate the energy consumption and mobile network operators OPEX. In this work, we consider a deployment of heterogeneous BSs to serve a given geographical area and propose two energy-aware algorithms to optimally determine the operational mode of those BSs under various traffic load conditions. Performance evaluation results show that the proposed algorithms can provide near optimal solutions and achieve substantial network energy consumption reduction without compromising the efficient operation of the mobile network. We further benefit from the outcome of this formulation framework and propose BS activation schemes that yield proper BS activation profiles for continuous-time operation in the same network deployment. Various traffic loads are investigated in several simulation campaigns and our proposed schemes yield quite satisfactory energy saving gains compared to fully operational topology networks in all scenarios of interest examined.     

WLAN技术在软交换系统中的应用

文章主要讨论无线局域网（WLAN）如何接入软交换系统,通过对WLAN技术标准、网络架构及承载能力的探讨,揭示了软交换系统无线应用面临的挑战,在此基础上给出了一些有前景的应用,如VoWLAN、远程无线监控、无线即时消息和定位服务等的解决方案。文章认为宽带无线接入标准WiMAX有望成为WLAN的升级版,一旦成熟,并与软交换等NGN技术相结合,将会实现人们追求的。网络无所不在,信息随手可得”的美好愿望。     

An Adaptive Fuzzy C Means with Seagull Optimization Algorithm for Analysis of WSNs in Agricultural Field with IoT

In recent years, the environmental monitoring in agriculture field is an essential required application. To achieve the environmental monitoring of agriculture fields, the wireless sense networks (WSN) and internet of things is utilized. In the WSN, the energy consumption is a main issue to access the medium and transfer the networks. Hence, in this paper, adaptive fuzzy C means clustering and seagull optimization algorithm is developed for monitoring environmental conditions in agriculture field. Two main objective functions are utilized to empower the presentation of the WSN such as load balancing and energy efficient operation. The proposed method is a combination of fuzzy C means clustering and seagull optimization algorithm (SOA). The energy efficient and load balancing is achieved by optimal routing scheme by proposed method. The fuzzy C-means clustering is utilized to empower the energy efficient operation and load balancing. In the fuzzy C-means clustering, the SOA is utilized to select the optimal path selection. The proposed method is executed by NS2 simulator and performances are compared with existing methods such as atom search optimization and emperor penguin optimization respectively. The performance metrics are delay, drop, throughput, energy consumption, network lifetime, overhead and delivery ratio.