一种多出口的WiMAX Mesh回程网络资源调度算法

由于WiMAX Mesh网络可以有效保证网络的QoS,因此有可能将其应用于电信级的回程网络.本文分析了WiMAX Mesh网络的调度机制和单出口 WiMAX Mesh网络存在的问题,提出了一种多出口WiMAX Mesh网络组网方案,在该方案的基础上提出了全局最优的调度算法,并给出了把该算法应用到实际WiMAX Mesh网络中的详细步骤.本文对具有20个和50个SS节点的Mesh网络进行了仿真,对算法的性能和效果进行了验证.仿真结果表明,本算法可以把调度效率提高53%～70%.     

A Novel High Performance Routing Algorithm for Mobile Multi-hop Tunneling Networks

Wireless Personal Communications - In recent years, the social internet of things (SIoT) has become a research hot topic in the field of wireless networks, which are inseparable relationships...     

Multi-Hop WiMAX Networks: A New Opportunistic Algorithm Using AMC and PUSC Mode for Different Mobility Users

Resource allocation algorithms play the main role in provisioning high throughput in broad band wireless communications. The previous studies in WiMAX networks have considered either AMC or PUSC techniques for the resource allocation algorithms. In this way, AMC based algorithms have presented high throughput for low speed users. Conversely, PUSC based algorithms have not been affected by users’ speed, whilst the throughput is low. To date, the importance of presenting proportional fair and maintaining the network throughput for the users with different speeds has not been acknowledged yet. This paper presents a novel opportunistic algorithm which is suitable for the users with different mobility speeds. The new algorithm uses two modes of AMC and PUSC simultaneously. The simulation results reveal that in comparison to similar algorithms, the proposed algorithm presents more proportional fair throughput when there are both high and low speed users.     

一种跨层设计的WiMAX上行链路调度算法

本文研究了WiMAX系统PMP(point to multi-point)模式下的调度算法,并综合考虑MAC层的队列状况/物理层的信道条件以及业务流的QoS要求,跨层设计了一种能够动态适应调制编码方案和信道干扰的上行链路调度算法--DMIA(dynamic MCS and intederence aware scheduling algorithm),最后利用NS2建模仿真,结果表明,与RR、WRR以及PQ+PF算法相比,本文提出的算法具有更高的吞吐量,更小的时延、时延抖动和丢包率,能满足各类业务的QoS要求.     

WiMAX网络的自适应切换算法

宽带无线通信由于载频的不断提高使得覆盖网络的半径越来越小,切换将变的更加频繁。针对不同移动用户,提出了一种基于移动速度的自适应切换算法,在切换过程中目标基站通过自适应的调整切换的延时时间来提高切换质量,降低了切换的掉话率。仿真表明,该策略可以有效降低切换掉话率,得到了一个比较完善的切换机制,可广泛用于将来宽带无线通信融合网络的切换中。     

一种适用于宽带无线IP网络的分组调度算法

自适应调制技术在许多新型的无线分组网络如WCDMA HSDPA、HiperLAN/2中得到广泛采用.本文在充分考虑自适应调制系统链路带宽随时隙呈不平均分布特点的基础上,提出一种全新的调度算法,自适应区分补偿公平队列(ADCFQ).该算法采用了基于工作量的分析方法,设计了不同功能的多个子队列,可以为系统所有待发流提供基本的QoS保证,为各个流公平共享剩余带宽,并能够通过合理的补偿机制克服无线环境中突发错误影响.分析和仿真结果表明,这一算法可以满足目标要求.此外,仿真中,针对自适应链路的特点,本文还提出了一种基于多状态Markov链的信道建模方法.     

基于MIH的WLAN/WiMAX宏移动性研究

下一代无线网络将是异构IP网络,为了提供无缝切换服务,结合IETF提议的移动IPv6(MIPv6)协议与IEEE802.21工作组提出介质独立切换(MIH)标准,设计出一种基于MIH异构网络宏移动性的垂直切换方案。在NS-2仿真环境中,验证了此方案的可用性,详细分析了网络切换时延和丢包率,并根据分析结果提出进一步研究方向。     

EGPRS中新的调度算法

EGPRS（Enhanced GPRS）网络中，为不同用户分配物理信道PDCH（Packet Data Channel）的传统调度算法是PF（Proportionally Fair）算法。文中介绍了一种新的调度算法OHA（Opportunistic Handling Algorithm），该算法可以根据用户使用的不同服务类别为用户提供不同的服务质量；最后对OHA算法和PF算法的性能进行了比较。     

A Novel SIP-Based Route Optimization for Network Mobility

With the provision of various wireless services, e.g., third-generation (3G) and wireless local area network (WLAN), more and more people request to access the Internet anywhere at anytime. For example, people want to check their e-mails on the bus or watch online news while traveling in the train. For this purpose, the Internet Engineering Task Force (IETF) proposed the concept of network mobility, i.e., a set of users move as a unit. We motivate the network mobility problem by considering the state-of-the-art scenario of the network mobility (NEMO) basic support protocol that is extended from the Mobile IPv6 (MIPv6). In order to avoid the same problems suffered by MIPv6, a new session initiation protocol (SIP)-based network mobility management scheme called SIP-NEMO is designed and proposed in this paper. The proposed SIP-NEMO not only copes with the movement of a mobile network but also achieves the route optimization between two SIP clients without too many signaling messages over wireless links, even if the mobile network is nested. In this paper, we also analytically compute and simulate the performance of SIP-NEMO with the NEMO basic support protocol proposed by the IETF.     

一种低功耗的多跳无线传感网时间同步算法

高精度低功耗的时间同步对于无线传感网络至关重要,文中重点分析了高精度时间同步算法,发现其在多跳网络时间同步过程中由于每跳范围内所有节点均要广播时间同步包,会产生大量的冗余信息。为降低同步功耗,提出了一种新方法,通过调节发射功率,筛选出每一跳范围内的周边节点,使其完成下一跳范围的时间同步,而非周边节点只接受却不发送时间同步包。最后,针对改进的算法在OMNet++上进行了仿真实验,仿真结果表明,改进后的算法能够有效地降低全网能量消耗。     

一种EPON-WiMAX融合网络带宽分配算法

文中提出了一种应用于EPON和WiMAX的融合网络,实现用户多优先级业务区分并保证用户QoS的动态带宽分配算法。算法让EPON网络和WiMAX网络协同分配带宽,在EPON网络带宽分配的过程中加入WiMAX网络的带宽分配。整体算法使得因得不到足够带宽而受到影响的用户数保持在最小,同时加入令牌机制兼顾了用户之间的公平性。文中在现有融合网络框架的基础上提出算法,并给出了算法的具体设计步骤,详细分析了带宽申请和分配的过程,讨论了算法的优越性。     

CoMP系统低复杂度集中式调度算法研究

在3GPPLTE—A网络中,可以使用CoMP（多点协作）技术来提高边缘用户的性能。为了最大化全网边缘用户的总吞吐量,关键是要确定在每个PRB（物理资源块）中同时被服务的用户集合、每个被调度用户所对应的协作基站、以及各基站的传输功率。基于每个边缘用户的RSRP（参考信号接收功率）,提出一种低复杂度的集中式传输调度算法,针对每个PRB中被服务的边缘用户和相应的协作基站进行动态选择,并通过仿真实验验证算法的性能增益。     

A Novel Battery-Aware Task Scheduling Algorithm for Multiprocessor Systems

In battery-powered portable devices, the most important design goal is maximizing the battery lifetime. This paper addresses the problem of battery- aware task scheduling on multiprocessor systems to extend the battery lifetime, and proposed a Critical-path based battery-aware task scheduling （CPbBATS） algorithm with a novel efficient flow. Experiments on hundreds of task graphs each having 10 to 100 tasks show that, compared with algorithm that simply sequences tasks with their highest voltages and utilizes the slack by the latest possible task, the CPbBATS achieved 3.3%-6.1% reduction on apparent charge lost which means longer battery lifetime, 3.6%-8.3% reduction on actual charge lost which means lower energy consumption, and average 31.99% reduction on the CPU runtime which means much lower computa- tional complexity.     

A Novel Distributed Scheduling Algorithm for Downlink Relay Networks

To extend network coverage and to possibly increase data packet throughput, the future wireless cellular networks could adopt relay nodes for multi-hop data transmission. This letter proposes a novel distributed scheduling algorithm for downlink relay networks. Soft-information indicating the probability of activating each network link is exchanged iteratively among neighboring network nodes to determine an efficient schedule. To ensure collision-free simultaneous data transmissions, collision-avoiding local constraint rules are enforced at each network node. To increase resource utility, the soft-information is weighted according to the urgency of data transmission across each link, which also helps maintain throughput fairness among network users.     

一种分层多跳无线网中的移动性管理策略

该文介绍一种分层多跳无线网与其他骨干网络互连情况下的网络层移动性管理方案。它使用了包含逻辑家乡代理的宏移动性管理和将位置管理与路由和寻呼机制结合起来的微移动性管理的思想,以提高网络在战场等特殊情况下使用的可靠性和抗毁性,减小位置管理的开销,节省无线信道的带宽。     

一种适应信道的WiMAX分级调度架构

针对无线信道中与时间和位置相关性错误,文章简要介绍了IEEE 802.16d协议[1]的QoS服务模型,在对WiMAX的QoS机制和调度策略进行了深入的研究后,提出了一种新的MAC层分级分组调度架构.该架构主要由调度控制器、流量监控和两级分组调度组成,并给出了关键调度的算法模型.对算法的仿真表明,这个调度架构能够有效地区分对待实时业务、非实时业务和BE业务,满足不同类型业务的QoS需求,解决了无线信道特殊性带来的调度问题.     

一种用于前向分组数据业务的新调度算法

该文通过分析前向分组数据业务中应用的各种调度算法的性能,指出调度算法的吞吐量和公平性之间必然存在着折衷关系.在满足给定的公平性要求的情况下,吞吐量累积分布函数曲线越靠近公平性准则,吞吐量越高.基于这个认识,该文提出一种新的调度算法,它可以通过调节参数来改变吞吐量和公平性曲线的关系.而且,从吞吐量和公平性曲线折衷的角度出发,可以比较容易地找出一种近似最优解.     

一种新的基于HSDPA系统的分组调度算法

传统的HSDPA分组调度算法利用信道状态的变化来选择信道质量相对较好的用户,以此来达到吞吐量最大化.然而,由于信道质量较差的用户无法获得服务而被"饿死",因而这将引起公平性的问题.文章在分析了传统调度算法的基础上,提出了一种新的M-LWDF算法,并通过了计算机仿真,论证了新的算法在公平性方面较改进前有了较大的提高.     

A Novel Technique for Channel Estimation and Equalization for High Mobility OFDM Systems

Orthogonal frequency division multiplexing (OFDM) technique, when used in wireless environments, is known to be robust against frequency selective fading. However, when the channel shows time selective fading, rapid variations destroy the subcarrier orthogonality and introduce inter-carrier interference (ICI). The use of ICI mitigation schemes requires the availability of channel state information (CSI) at the receiver, which is a non-trivial task in fast fading systems. In our work, we have addressed the problem of estimation of rapidly varying channels for OFDM systems. The channel is modeled using complex exponentials as basis functions and the estimation process makes use of the cyclic prefix (CP) part available in OFDM symbols as training. The system is viewed as a state space model and Kalman filter is employed to estimate the channel. Following this, a time domain ICI mitigation filter that maximizes the received SINR (signal to interference plus noise ratio) is employed for equalization. This method performs considerably well in terms of MSE as well as BER at very high Doppler spreads.