A Novel Scheduling Algorithm for Low and High Mobility Users in Multi-hop WiMAX Network

QoS provisioning and high capacity for high mobility users are considered as the distresses of broadband wireless communications (BWC) and specifically the key technology of WiMAX. Hence, the scheduling and resource allocation algorithms play the main role in this regard. In the research conducted on scheduling algorithms in WiMAX network, two principal methods of AMC and PUSC are used. The high capacity in AMC mode algorithms is achieved by considering the low speed users. Conversely, in PUSC mode algorithms, speed does not affect the network performances; however, the capacity is low. To date, the importance of presenting QoS and maintaining the network capacity for the users with different speeds has not been acknowledged yet. This paper presents novel scheduling algorithms and also new frame partitioning scheme which are proper for the users with different mobility speeds. The new algorithm uses two modes of AMC and PUSC simultaneously to maintain the high capacity of the network. QoS is also provided. The simulation results reveal that our algorithm increases capacity while it presents low packet delay and packet loss rate in the presence of both high and low mobility speed users.     

A Direction-Based Data Forwarding Algorithm for Opportunistic Networks

In this paper, the forwarding objective and mobility law of nodes in opportunistic networks are first investigated to establish a mathematical model for further analysis, then a gradually accelerated data forwarding algorithm is proposed. In this algorithm, according to the distance between data carriers (nodes) and the destination, some intermediate nodes are selected to relay the data. Especially, the forwarded copies can be increased when the delay reaches a threshold, to guarantee the required delivery ratio. The simulation results show that the proposed algorithm can effectively reduce the storage occupancies of nodes and forwarding delay, and guarantee the delivery ratio simultaneously.     

基于多跳聚合无线传感器网络的公平性竞争策略

为了降低节点间广播消息产生的冲突,文中提出一种基于多跳路由的无线传感器网络环境中的公平性策略,使得簇内节点在向簇首转发数据包时,可以采用一种更为公平的方式竞争信道,各层节点根据自己的权值大小获得发送数据包权限后在下一轮进入休眠状态,在保证公平性的同时有效节省监听时耗费的能量,达到提高网络生命周期的目的.     

机载多跳波分复用网络时间确定性分析方法

波分复用技术有望应用于航空电子系统的综合化互连,特别是传感器前端处理部分的实时网络互连。根据机载多跳波分复用网络的关键部件波长路由器的结构,对实时通信流量特性和优先级排队的服务特性进行建模,给出突发度、服务时延等参数指标的计算方法,并在高优先级时间触发流量的压力下,提出了在机载多跳波分复用网络中事件触发流量的最坏情况下,端到端延迟的网络演算方法;使用该方法计算得到的结果可以作为机载波分复用网络时间确定性分析的依据。将最坏情况下的分析结果与软件仿真结果相对比,发现两者变化规律相符,验证了该方法的有效性。     

BlueMesh: Degree-Constrained Multi-Hop Scatternet Formation for Bluetooth Networks

In this paper we describe BlueMesh, a new protocol for the establishment of scatternets, i.e., multi-hop wireless networks of Bluetooth devices. BlueMesh defines rules for device discovery, piconet formation and piconet interconnection so to generate connected scatternets with the following desirable properties. BlueMesh forms scatternets without requiring the Bluetooth devices to be all in each other transmission range. BlueMesh scatternet topologies are meshes with multiple paths between any pair of nodes. BlueMesh piconets are made up of no more than 7 slaves. Simulation results in networks with over 200 nodes show that BlueMesh is effective in quickly generating a connected scatternet in which each node, on average, does not assume more than 2.4 roles. Moreover, the route length between any two nodes in the network is comparable to that of the shortest paths between the nodes.     

自适应喷雾聚焦机会网络路由算法

针对现有喷雾路由算法不能依据实际情况动态调整消息拷贝数,而导致资源浪费的问题,提出一种自适应喷雾聚焦路由算法ADPSF。ADPSF依据节点密度估算消息拷贝数,依据相遇概率历史信息选择中继节点和分配消息副本数。仿真试验表明,ADPSF算法在保证消息交付率和时延的情况下有效降低网络开销。     

Throughput Performance Analysis of AMC Based on a New SNR Estimation Algorithm Using Preamble

The rapid growth in mobile communication users necessitates the development of reliable communication systems that provide higher data rates. To meet these requirements, techniques such as multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) have been developed in recent years. Current research activity is focused on developing MIMO-OFDM systems that combine the benefits of both techniques. In addition, for a fast wireless channel environment, the data rate and reliability can be optimized by setting the modulation and coding adaptively according to the channel conditions, as well as by using sub-carrier frequency and power allocation techniques. The overall system performance depends on how accurately the feedback-based system obtains the channel state information and feeds it back to the transmitter without delay. In this paper, we propose a signal-to-noise ratio (SNR) estimation algorithm in which the preamble is known for both sides of the transceiver. Also, we applied AMC on several channel environments using the parameters of IEEE 802.11n and compared throughput performance using each of the different SNR Estimation Algorithm. The results obtained prove that our proposed algorithm is more accurate than traditional algorithms.     

移动WiMAX和其他3G标准的混合组网及其切换新策略

从发展趋势、开放的无线结构角度,推出了WiMAX与其他3G标准的组网结构,开放有效,安全透明.推出的WiMAX与3G的垂直切换新策略及其流程,减少了切换中断时间,达到了实际上的无缝漫游与信息数据的零丢失.     

QMCR:A Q-Learning-Based Multi-Hop Cooperative Routing Protocol for Underwater Acoustic Sensor Networks

Routing plays a critical role in data transmission for underwater acoustic sensor networks (UWSNs) in the internet of underwater things (IoUT). Traditional rout...     

Mobility Aware Quality Enhanced Cluster Based Routing Protocol for Mobile Ad-Hoc Networks Using Hybrid Optimization Algorithm

Wireless Personal Communications - Wireless Sensor Networks (WSN) utilizes more nodes to forward messages and information from source node to destination node and these nodes are battery-powered...     

一种新的无线传感器网络DV-Hop算法

无线传感器网络[1]能够实时监测和采集网络分布区域内的各种检测对象信息,有着广泛的应用前景。节点自身定位是无线传感器网络的基础性问题之一。节点定位算法大致可分为两类:基于测距的算法和无需测距的算法。基于测距的算法对硬件的要求较高,无需测距的对硬件的要求不高。针对这种情况,为了提高算法精度,文中介绍了一种名叫RDV-hop算法的新的节点定位算法,这种算法结合RSSI与DV-hop两种算法的优点来进行节点定位。与老的DV-hop算法相比,这种新的算法极大的提高了定位的精确度。     

使用IEEE 802.21的WLAN与WiMAX网的融合与切换

为了给移动用户提供最好的无所不在的无线宽带接入,不同无线网的融合是当前通信领域的热点研究。而切换管理又是解决无线网无缝融合的最具挑战性的问题。文中讨论了IEEE 802.11WLAN与IEEE 802.16e移动WiMAX网的融合与切换管理。描述其结构和应用场景,介绍了IEEE802.21,它为介质独立的异类网切换提供了一个信令框架,提出了如何使用IEEE802.21解决WLAN与移动WiMAX网之间的切换,并给出了详细的切换过程。说明了使用IEEE 802.21解决WLAN与移动WiMAX网之间的切换是可行有效的。     

MAC Protocol Design and Optimization for Multi-Hop Ultra-Wideband Networks

Ultra-wideband (UWB) communication is a promising enabling technology for future broadband wireless services. A simple, scalable, distributed, efficient medium access control (MAC) protocol is of critical importance to utilize the large bandwidth UWB channels and enable numerous new applications and services cost-effectively. In this paper, by investigating the characteristics of UWB communications, we propose a Distributed, EXclusive region (DEX) based MAC protocol. The proposed DEX protocol capitalizes on the spatial multiplexing gain of UWB networks by reserving exclusive regions (ER) surrounding the sender and receiver for data and acknowledgment (ACK) transmissions, so that users can efficiently and fairly share network resources in a distributed and asynchronous manner. We further quantify the network performance bounds and derive the optimal ER size to maximize the expected network transport throughput for a dense, multi-hop UWB network. Extensive simulation results demonstrate the efficiency and effectiveness of the DEX protocol. This work explores how to effectively utilize the wireless spatial capacity of distributed, multi-hop wireless networks by optimizing protocol parameters, instead of depending on more complicated control messages.     

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.     

PQBCF：一种基于中间中心度的机会网络P2P查询算法

社会机会网络由人携带的带有短距离通信接口的移动设备利用人的移动形成,其数据采用“存储-携带-转发”的模式进行传输,本文针对这类网络,提出了一种基于中间中心度的P2P查询算法（P2P Query based on Between-ness Centrality Forwarding ,PQBCF）。节点的中间中心度描述了节点在信息传输转发过程中的参与度和重要度,PQBCF算法通过选择具有较大中间中心度的节点来实现信息的高效转发。仿真实验表明,与目前该研究领域的SF （Spray and Fo-cus ）等主流算法相比,PQBCF算法能够有效提高查询成功率,并降低查询延时。     

一种新的HPRF目标跟踪算法

高重复频率(HPRF)在脉冲多普勒雷达上应用正日益广泛,距离高度模糊是其面临的难题之一.文中提出了一种新的HPRF目标跟踪算法,利用距离参数化和概率数据关联算法,能快速得到目标距离的模糊倍数,该方法的特点是不需要调频测距,在波形调度上类似于中重复频率,从而降低了雷达设计难度,简化了数据处理流程,在工程中有较好的应用前景.本文最后还进行了大量的数据仿真,验证了该算法的技术可行性和有效性.     

一种精确计算容差网络的新算法

论述了应用Markov区间迭代法对含有容差的网络进行节点电压分析。文中首先介绍Markov区间选代法的基本方法，然后把这种方法应用于容差网络的节点电压计算，并把计算结果与Hansen迭代法进行比较。结果表明，这种方法具有较高的计算精度，它不仅能够用于电路的分析而且也能够用于容差网络的故障诊断。     

A New Algorithm for the Weighted Reliability of Networks

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