New mixed broadcast scheduling approach using neural networks and graph coloring in wireless sensor network

Due to the mutual interference and sharing of wireless links in TDMA wireless sensor networks, conflicts will occur when data messages are transmitting between nodes. The broadcast scheduling problem （BSP） is aimed to schedule each node in different slot of fixed length frame at least once, and the objective of BSP is to seek for the optimal feasible solution, which has the shortest length of frame slots, as well as the maximum node transmission. A two-stage mixed algorithm based on a fuzzy Hopfield neural network is proposed to solve this BSP in wireless sensor network. In the first stage, a modified sequential vertex coloring algorithm is adopted to obtain a minimal TDMA frame length. In the second stage, the fuzzy Hopfleld network is utilized to maximize the channel utilization ratio. Experimental results, obtained from the running on three benchmark graphs, show that the algorithm can achieve better performance with shorter frame length and higher channel utilizing ratio than other exiting BSP solutions.

Network Coding-based Reliable Broadcast Transmission in Wireless Networks

Recently, network coding has been applied to the loss recovery of reliable broadcast transmission in wireless networks. Since it was proved that fi nding the optimal set of lost packets for XOR-ing is a complex NP-complete problem, the available time-based retransmission scheme and its enhanced retransmission scheme have exponential computational complexity and thus are not scalable to large networks. In this paper, we present an efficient heuristic scheme based on hypergraph coloring and also its enhanced heuristic scheme to improve the transmission efficiency. Basically, our proposed schemes fi rst create a hypergraph according to the packet-loss matrix. Then our schemes solve the problem of generating XORed packets by coloring the edges of hypergraph. Extensive simulation results demonstrate that, the heuristic scheme based on hypergraph coloring and its enhanced scheme can achieve almost the same transmission efficiency as the available ones, but have much lower computational complexity, which is very important for the wireless devices without high computation capacity.

Impact of small-world topologies on broadcasting for wireless sensor networks

Broadcasting is an important operation and been widely used in wireless sensor networks （WSNs）. These networks are power constrained as nodes operate with limited battery power. Wireless sensor networks are spatial graphs that have much more clustered and much high path-length characteristics. After considering energy- efficient broadcasting in such networks, by combining the small-world characteristic of WSNs and the properties of ant algorithm to quickly identify an optimal path, small-world power-aware broadcast algorithm is introduced and evaluated. Given different densities of network, simulation results show that our algorithm significantly improves life of networks and also reduces communication distances and power consumption.

A Preamble-Based Broadcasting Technique for Wireless Ad Hoc Sensor Networks

Broadcasting is a fundamental operation in any wireless networks, more so in wireless ad hoc sensor networks, where each sensor node has limited transmission range as well as battery power. Although broadcasting in wireless ad hoc sensor networks has many advantages but it can cause serious problems like-broadcast storm, which could cause a lot of contention, redundant retransmission, collision and most importantly, drain immense amount of energy from limited battery powered sensor nodes. In this work, our objective is to reduce the number of retransmission and energy consumption of sensor nodes by using the duty cycle property of wireless ad hoc sensor networks. We propose a preamble-based broadcasting technique for wireless ad hoc sensor networks. We show that in dense wireless ad hoc sensor networks a small size preamble can give maximum network-wide data dissemination rather than using the large preamble, which will only consume immense amount of energy during packet reception.

Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks

Wireless sensor networks （WSNs） consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization （BACRIL） in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500.

On the Mathematical Nature of Wireless Broadcast Trees

Trees are arguably one of the most important data structures widely used in information theory and computing science. Different numbers of intermediate nodes in wireless broadcast trees may exert great impacts on the energy consumption of individual nodes, which are typically equipped with a limited power supply in a wireless sensor network; this limitation may eventually determine how long the given wireless sensor network can last. Thus, obtaining a deep understanding of the mathematical nature of wireless broadcast trees is of great importance. In this paper, we give new proof of Cayley＇s well-known theorem for counting labeled trees. A distinct feature of this proof is that we purely use combinatorial structures instead of constructing a bijection between two kinds of labeled trees, which is in contrast to all existing proofs. Another contribution of this work is the presentation of a new theorem on trees based on the number of intermediate nodes in the tree. To the best of our knowledge,this work is the first to present a tree enumeration theorem based on the number of intermediate nodes in the tree.

基于最大完全子图与最小树形图的无线定向网络广播算法

现有关于无线定向网络广播的研究主要集中于如何选择中继节点或计算转发概率以提升分组递交率,减少广播冗余,但未对中继节点选择及波束指向计算开展联合设计,导致源节点及中继节点在广播过程中存在冗余指向,增加了消息转发次数。为提升无线定向网络广播效率,提出一种基于最大完全子图与最小树形图的无线定向网络广播算法(maximum complete subgraph and minimum arborescence based directional broadcasting algorithm,MCSMA)。算法首先利用最大完全子图理论计算源节点或中继节点波束指向,使单个波束指向覆盖的邻居节点数量最多,然后利用最小树形图理论选择中继节点,使中继节点使用少量波束覆盖全网所有节点,降低广播过程中的消息转发次数。仿真表明,所提算法可有效减少广播过程中源节点和中继节点的波束指向次数,提升定向广播效率。

扩音对讲系统在LNG接收站的应用及发展综述

分析适用于LNG接收站的扩音对讲系统设计方法。从系统结构、工作原理、传输方式、功能特点等方面详细论述了无主机型扩音对讲系统、有主机型扩音对讲系统、全数字IP型扩音对讲系统和5G型扩音对讲系统这四种扩音对讲系统的功能特点和差异性。通过对四种扩音对讲系统在LNG接收站中应用的优缺点和发展局限性分析对比,提出了在我国现阶段LNG接收站中应用最为广泛的扩音对讲系统设计方案为全数字IP型扩音对讲系统。通过介绍扩音对讲系统的功能和全数字IP型扩音对讲系统在LNG接收站应用案例,详细介绍了数字IP型扩音对讲系统在LNG接收站中的设计方法。阐述了基于5G网络技术的5G型扩音对讲系统在LNG接收站应用的局限性并对其发展进行了展望。

数字化时代广播电视无线发射技术的发展研究

在数字化时代,开发广播电视无线发射技术时,需要根据技术执行特征和需求更新原有技术模式,贯彻因地制宜的工作原则。同时,对传统广播电视无线发射中出现的各种问题进行有效处理,并深度优化现有工作方案,确保广播电视无线发射技术的执行效果,提高广播电视产业发展水平。针对数字时代背景下广播电视发射信号中心构成和广播电视无线发射技术的特点进行研究,为广播电视相关工作提供借鉴。

无线数字覆盖技术在广播工程中的应用

阐述无线数字覆盖技术的特点,探讨基于无线数字覆盖技术的广电工程系统架构,包括前端系统、单频网络调试系统、卫星传输系统、多频网络系统、地面数字广播系统,分析无线数字覆盖技术在广电工程中的应用。

广播信号无线发射技术的运用研究

为进一步提高广播信号传输质量,要结合广播信号应用运行环境要求,合理调控运行空间,发挥广播发射机等设备的重要作用,为广播传媒工作稳定发展提供保障。文章简要分析广播信号无线发射技术工作原理,并对关键技术内容展开讨论,针对广播信号无线发射技术应用提出相应建议。

无线发射台站智慧运维支撑管理系统审计日志模块的设计与实现

阐述应用于广播电视无线发射台站智慧运维支撑管理系统审计日志模块的总体设计思路和实现要点。该模块通过对系统操作和事件进行全面收集、存储、分析和告警通知,旨在提高广播电视的安全播出和网络安全水平。

Multimedia Streaming for Ad Hoc Wireless Mesh Networks Using Network Coding

Over the past years, we have witnessed an explosive growth in the use of multimedia applications such as audio and video streaming with mobile and static devices. Multimedia streaming applications need new approaches to multimedia transmissions to meet the growing volume demand and quality expectations of multimedia traffic. This paper studies network coding which is a promising paradigm that has the potential to improve the performance of networks for multimedia streaming applications in terms of packet delivery ratio (PDR), latency and jitter. This paper examines several network coding protocols for ad hoc wireless mesh networks and compares their performance on multimedia streaming applications with optimized broadcast protocols, e.g., BCast, Simplified Multicast Forwarding (SMF), and Partial Dominant Pruning (PDP). The results show that the performance increases significantly with the Random Linear Network Coding (RLNC) scheme.

Grid-based directed diffusion for wireless sensor networks

Directed diffusion is a data dissemination protocol for wireless sensor networks.In directed diffu-sion,flooding is used for dissemination of interest and exploratory data,which will bring broadcast stormresulting in substantial energy consumption of networks.A grid-based directed diffusion is presented toimprove the energy efficiency of directed diffusion.Virtual geographic grid clusters are constructed byself-organization of nodes using geographic location information.The flooding of interest and exploratorydata of original directed diffusion is limited in cluster head nodes.The simulation results and testhed ex-periments show that the method effectively reduces the network energy consumption.This gain is notachieved at the cost of either delivery ratio or the delay.Importantly,the decreased load also leads to abetter delivery ratio and lower delay.

An Analytical Study of Variable Preamble Length-Based Broadcasting Scheme for WSNs

In this paper, we present a detailed analytical study of previously proposed variable preamble length-based broadcasting scheme for wireless sensor networks (WSNs). Analytical results show that in dense wireless sensor networks, broadcasting a packet with a small size preamble can significantly improve the energy conservation on already limited battery powered sensor nodes. For fairer comparison with variable preamble length-based broadcasting scheme, a comprehensive analytical study for an existing probability-based broadcasting scheme is also presented. Analytically calculated results show that variable preamble length-based broadcasting scheme is more energy-efficient than the probability-based broadcasting scheme.

数字技术在广播电视无线覆盖中的运用研讨

数字技术所具备的通用性强、保密性高,以及存储时间长等一系列优势,使其在广播电视无线覆盖中得到广泛应用,可确保广播电视信号的稳定性,同时使音视频传播更为清晰与流畅。尝试侧重对数字技术在广播电视无线覆盖中的应用问题进行分析与探讨,概括完善无线数字化覆盖工程技术框架、科学掌握传输频率、数字音频调音与云技术、合理降低传输损耗以及合理降低传输损耗这5个方面的内容,对广播电视节目影响力以及覆盖范围的进一步拓展有重要意义,值得引起业内关注与重视。

广播电视无线数字化覆盖工程信号源传输功能实现方法

科技发展越来越快,广播电视、手机、电脑、平板等电子设备随处可见,我国的广播也开始迈向一个全新的阶段.广播电视数字化技术不断发展,广播电视无线数字化覆盖工程信号源传输方案需要不断优化才能适应时代发展的需要.介绍了工程信号源传输的概念,分析并总结了广播电视无线数字化覆盖工程信号源传输的实施方案,探讨了广播电视无线数字化覆盖工程信号源传输功能的实现方法以及新的发展方向.

数字时代的广播电视无线发射技术

数字时代的到来,推动了广播电视无线发射技术的迅猛发展。探讨数字化技术在广播电视无线发射中的应用以及新型无线发射技术的发展趋势。首先,概述无线传输技术的定义、原理及其在数字时代的演变和发展;其次,重点分析数字音频传输技术和数字视频传输技术在广播电视领域的应用;最后,探讨新型无线发射技术的未来发展趋势。

基于定向天线的无线Mesh网络广播技术

本文研究基于微时隙划分的时分复用,选择适用于多接口定向天线的空分复用共享技术,实现无线Mesh网络广播时延、可靠性、冗余率以及耗时等相关性能指标的优化,进而提升无线广播综合性能。研究结果表明,基于定向天线的无线Mesh广播技术可以在很大程度上提升广播效率,达到了广播按需分配的目的。