基于移动锚节点的无线传感网络节点定位算法

在无线传感网络定位算法中,锚节点位置决定了节点定位精度。为此,提出基于高斯-Markov模型的移动锚节点的节点定位(GM-MAL)算法。GM-MAL算法基于高斯-Markov移动模型,提出自适应锚节点的移动路径规划,通过速度调整策略、垂直平分线策略、虚斥力策略以及虚引力策略规划路径。在定位阶段,将非凸优化问题转化为双凸形式,再利用交替最小算法(AMA)求解,进而获取更短的锚节点移动路径。实验数据表明,引入虚引力策略提高了路径规划精度,覆盖了更多的监测区域。此外,相比于线性算法,GM-MAL的定位精度得到提高。     

Dynamic clustering approach with ACO-based mobile sink for data collection in WSNs

Enhancing the network lifetime of wireless sensor networks is an essential task. It involves sensor deployment, cluster formation, routing, and effective utilization of battery units. Clustering and routing are important techniques for adequate enhancement of the network lifetime. Since the existing clustering and routing approaches have high message overhead due to forwarding collected data to sinks or the base station, it creates premature death of sensors and hot-spot issues. The objective of this study is to design a dynamic clustering and optimal routing mechanism for data collection in order to enhance the network lifetime. A new dynamic clustering approach is proposed to prevent premature sensor death and avoid the hot spot problem. In addition, an Ant Colony Optimization (ACO) technique is adopted for effective path selection of mobile sinks. The proposed algorithm is compared with existing routing methodologies, such as LEACH, GA, and PSO. The simulation results show that the proposed cluster head selection algorithm with ACO-based MDC enhances the sensor network lifetime significantly.

     

一种改进的应用于无线传感器网络的拜占庭容错方案

研究了传统拜占庭容错方案并针对无线传感器网络的特定环境加以改进,减少了传统方案中网络节点间消息交换轮数,提高了效率并降低了通信开销和能量消耗,仿真结果表明:设计的方案在使所有正常网络节点达成一致的同时,其使用的消息交换轮数与传统拜占庭方案相比有显著的下降.     

A multicast mechanism for mobile networks

This letter proposes a multicast table approach to support GSM/UMTS multicast that minimizes the paging cost. The implementation and execution of the multicast tables are very efficient. The costs for updating these tables can be ignored compared with the costs of standard location update procedures. Furthermore, our mechanism can be implemented within the mobility databases without modifying the standard location update messages. We show that our mechanism always outperforms the existing GSM/UMTS multicast mechanisms     

An Improved PSOGSA for Clustering and Routing in WSNs

Wireless Personal Communications - Wireless sensor network (WSN) is an integration of sensing, communicating, computing in a board range environment. Efficient energy consumption becomes the most...     

An energy-efficient overlapping clustering protocol in WSNs

Wireless Networks - The limited battery power supply system makes energy efficiency a major concern in WSNs. An effective method is to organize the sensors into clusters to avoid redundancy and...     

A multicast mechanism for mobile multimedia messaging service

Based on the cell broadcast service architecture, this paper proposes an efficient multicast mechanism for the universal mobile telecommunications system to support multimedia messaging service (MMS). We define a new interface between the serving GPRS support node and the cell broadcast center to track the current locations of the multicast members. Then we describe the location tracking procedures (including attach, detach, and location update) of the multicast members and the multicast message delivery procedure. We use an analytic model to investigate the performance of our approach. This paper indicates that our MMS multicast mechanism outperforms the previous proposed approaches.     

An efficient authentication protocol for mobile communications

In this paper, a new Global System of Mobile Communications (GSM) authentication protocol is proposed to improve some drawbacks of the current GSM authentication protocol for roaming users including: (a) communication overhead between VLR; (b) huge bandwidth consumption between VLR and HLR; (c) storage space overhead in VLR; (d) overloaded in HLR with authentication of mobile stations; and (e) not supporting bilateral authentication. The main contribution of this paper is that it does not only improve the drawbacks listed above but also fits the needs of roaming users. In addition, the proposed protocol does not change the existing architecture of GSM, and the robustness of the proposed protocol is the same as that of the original GSM, which is based on security algorithms A3, A5, and A8.     

An innovative drive for wheeled mobile robots

Introduced In this work is an innovative drive for wheeled mobile robots, that is based on two identical, coaxial wheels, independently driven by two identical motors. The common axis is capable of rotating about a vertical axis. The drive, termed dual-wheel transmission (DWT), is composed of two identical epicyclic gear trains, lying at two different levels and coupled by a common planet carrier. The latter can turn freely with respect to the robot platform carrying the motors, the transmission having as a stand-alone unit, three degrees of freedom and only two motors, which makes it underactuated. Upon coupling this drive with two other wheel units, which is the minimum required for static support, a robot with mobility of three is produced with the underactuation thereby disappearing. Finally, the dimensioning of the DWT is reported for robustness against manufacturing, actuation, and sensing errors.     

An integrated circuit for GSM mobile communications

An integrated circuit for the Pan European GSM mobile communications system is described which performs GMSK digital modulation and front-end functions for both base and mobile stations. The circuit includes, as main functional blocks, a 10-bit D/A converter, a 13-MHz switched-capacitor interpolating filter, and a power buffer. A fully differential approach was used. The circuit has been fabricated using a 2-m CMOS process. The chip size is 6.7×5.3 mm². The overall circuit performance fully meets GSM specifications.     

An MIMO-OFDM technique for high-speed mobile channels

In this letter, a new orthogonal frequency-division multiplexing (OFDM) technique for multiple-input multiple output (MIMO) channels is proposed to reduce interchannel interference (ICI) caused by high-speed mobiles in cellular environments. After analyzing the ICI caused by high-speed mobile channels using a simple curve fitting technique, the weighting factor for group transmission is optimized. Then, a new MIMO-OFDM technique, based on the weighting factor optimization, is proposed for reducing ICI caused by time-varying channels. Performances of the proposed technique are verified by using the I-METRA channel, proposed for an MIMO channel to 3GPP, and a MIMO-OFDM simulator designed for macrocellular mobile communication. It is shown by computer simulation that the proposed MIMO-OFDM technique is effective in reducing ICI and noise as well as in obtaining diversity gain even under highly-correlated fast fading channels, compared with the conventional MIMO-OFDM schemes.     

A Coverage-Based Scheduling Algorithm for WSNs

Node scheduling in wireless sensor networks (WSNs) plays a vital role in conserving energy and lengthening the lifetime of networks, which are considered as prime design challenges. In large-scaled WSNs, especially where sensor nodes are deployed randomly, 100 % coverage is not possible all the times. Additionally, several types of applications of WSNs do not require 100 % coverage. Following these facts, in this paper, we propose a coverage based node scheduling algorithm. The algorithm shows that by sacrificing a little amount of coverage, a huge amount of energy can be saved. This, in turns, helps to increase the lifetime of the network. We provide mathematical analysis, which verifies the correctness of the proposed algorithm. The proposed algorithm ensures balanced energy consumption over the sensor networks. Moreover, simulation results demonstrate that the proposed algorithm almost doubles the lifetime of a wireless sensor network by sacrificing only 5–8 % of coverage.     

Systematic energy-balanced cooperative transmission scheme in wireless sensor networks

Energy efficiency is a critical issue in wireless sensor networks(WSNs).In order to minimize energy consumption and balance energy dissipation throughout the whole network,a systematic energy-balanced cooperative transmission scheme in WSNs is proposed in this paper.This scheme studies energy efficiency in systematic view.For three main steps,namely nodes clustering,data aggregation and cooperative transmission,corresponding measures are put forward to save energy.These measures are well designed and tightly coupled to achieve optimal performance.A half-controlled dynamic clustering method is proposed to avoid concentrated distribution of cluster heads caused by selecting cluster heads randomly and to get high spatial correlation between cluster nodes.Based on clusters built,data aggregation,with the adoption of dynamic data compression,is performed by cluster heads to get better use of data correlation.Cooperative multiple input multiple output(CMIMO) with an energy-balanced cooperative cluster heads selection method is proposed to transmit data to sink node.System model of this scheme is also given in this paper.And simulation results show that,compared with other traditional schemes,the proposed scheme can efficiently distribute the energy dissipation evenly throughout the network and achieve higher energy efficiency,which leads to longer network lifetime span.By adopting orthogonal space time block code(STBC),the optimal number of the cooperative transmission nodes varying with the percentage of cluster heads is also concluded,which can help to improve energy efficiency by choosing the optimal number of cooperative nodes and making the most use of CMIMO.     

Multi-channel support for DMAC in WSNs

Currently most wireless sensor network applications assume the presence of single-channel medium access control (MAC) protocols. However, lower sensing range result in dense networks, single-channel MAC protocols may be inadequate due to higher demand for the limited bandwidth. In this paper we proposed a method of multi-channel support for DMAC in Wireless sensor networks (WSNs). The channel assignment method is based on local information of nodes. Our multi-channel DMAC protocol implement channel distribution before message collecting from source nodes to sink node and made broadcasting possible in DMAC. Analysis and simulation result displays this multi-channel protocol obviously decreases the latency without increasing energy consumption.     

Key establishment and management for WSNs

Wireless Sensor Networks (WSNs) are composed of a large number of low-cost, low-power, and multi-functional sensor nodes that communicate at short distances through wireless links. Those networks could be deployed in an open and hostile environment where attackers may be present. In this context, it is necessary to guarantee confidentiality, integrity and security services in the network. Those security properties could only be achieved if security associations have been created in the network between pairs of nodes, each node and the base station of groups of nodes. Those associations are created through key management protocols for pairwise or group establishment, distribution, renewing of cryptographic keys. Those protocols must only use information that is available in the network or pre-loaded in each sensor as the WSNs mus be autonomous. Moreover, due to the low-cost nature of each node, an attacker is able to compromise nodes because the nodes are not tamper-resistant. Thus a major challenge of the key management protocols becomes to preserve the general security of the network even if t nodes are compromised. We propose in this article a key management and access control protocol based upon a group deployment model. Moreover, this protocol is t-secure, i.e. t corrupted nodes are not sufficient to corrupt all the keys used in the network.     

An all-IP approach for UMTS third-generation mobile networks

This article describes the UMTS all-IP approach for third-generation mobile systems, with emphasis on the core network architecture. Following the introduction of the core network nodes, we elaborate on application-level registration, circuit-switched call origination, packet-switched call origination, and packet-switched call termination.     

An in-band power-saving protocol for mobile data networks

A new alternative is proposed for reducing the power consumption of the portable (battery-powered) units operating in a mobile packet-data network. First, a review of the current power-saving protocols is given. It is shown that the most common means for conserving power is the intermittent operation of the receivers (at the portable units) and a central administration authority that synchronizes the receivers. Some drawbacks of the synchronous operation lead us to the introduction of an asynchronous power-saving protocol, where no central synchronization is necessary and where each terminal may control its power consumption relative to its current needs. According to the proposed power-saving page-and-answer protocol, an acknowledgment paging procedure is preceding every packet transmission in order to alert mobile terminals with pending traffic. Steady-state performance is evaluated with the aid of simulation. The relationship between the achieved power-saving and the mean packet delay degradation is presented. Finally, we express some notable implementation issues and some considerations regarding the employment of this protocol as a supplementary power-saving service in microcellular mobile data networks and wireless local area networks     

An outband paging protocol for energy-efficient mobile communications

A new protocol is proposed for reducing the power consumption of battery-powered terminals in a mobile computing environment. We exploit the fact that, in a mobile data network, mobile terminals do not continuously receive data and therefore they need not continuously operate their receivers. Nevertheless, they need to check their traffic condition periodically, that is, whether there are pending data for them or not. The proposed energy-efficient protocol is based on a paging procedure wherein a dedicated channel is used to alert (page) terminals with pending traffic. Each terminal may check its traffic condition whenever it decides to by monitoring the paging channel. The protocol is evaluated through an approximated theoretical model and through computer simulation. We focus on deriving approximate formulas for the mean message delay, the message delay variance and the power consumption. It is shown that the proposed protocol can achieve considerable power saving at a cost of increased message delivery delay.     

An Energy Efficient Routing Algorithm for WSNs Using Intelligent Fuzzy Rules in Precision Agriculture

Wireless Personal Communications - Many agricultural activities can be highly enhanced by using sensor networks and data mining techniques. One of these activities is the regulation of the quantity...