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Adaptive application-driven WLAN power management

PERVASIVE AND MOBILE COMPUTING 2007年第3期3卷 255-275页

作者： Jiao, Yu Hurson, Ali R. Shirazi, Behrooz Penn State Univ Dept Comp Sci & Engn University Pk PA 16802 USA Washington State Univ Sch Elect Engn & Comp Sci Pullman WA 99164 USA

In this paper we present an adaptive application-driven power management (AADPM) strategy with online idle period length distribution learning capability for the IEEE 802.11b WLAN. We discuss its design and evaluate the performance in comparison with other power management strategies using the network simulator NS2. We simulated both the single user and multiple user scenarios. Experimental results have shown that, compared with other power management methods examined in this paper, AADPM achieved the highest energy saving in all cases and it demonstrated strong adaptability to network congestion. (C) 2007 Elsevier B.V. All rights reserved.

关键词： Energy-aware systems Mobile communication systems algorithm/protocol design and analysis

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Energy efficiency and error resilience in coordinated and non-coordinated medium access control protocols

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COMPUTER COMMUNICATIONS 2006年第17期29卷 3493-3506页

作者： Numanoglu, Tolga Tavli, Bulent Heinzelman, Wendi Univ Rochester Dept Elect & Comp Engn Rochester NY 14627 USA

Energy efficiency of a MAC protocol is one of the most important performance metrics, especially in mobile ad hoc networks, where the energy sources are limited. Two key factors in achieving energy efficiency for a MAC protocol are coordination among the nodes and schedule-based channel access. In order to achieve a sufficient level of coordination among the nodes, and hence to achieve energy efficiency, the exchange of control information via control packets is vital. As such, coordinated MAC protocols, which regulate channel access through scheduling, have been shown to achieve very high energy efficiencies when compared to non-coordinated MAC protocols, which do not employ scheduling. However, due to their increased vulnerability to channel errors, the performance of coordinated MAC protocols is affected more by the channel bit error rate (BER) than non-coordinated MAC protocols, which lack such control packets. In this paper, we investigate the energy efficiency and resilience against channel errors for coordinated and non-coordinated MAC protocols. Our results reveal that it is possible to achieve better system performance with coordinated MAC protocols even in lossy channels, provided that the BER level is not extremely high. (c) 2006 Elsevier B.V. All rights reserved.

关键词： energy-aware systems distributed networks wireless communication network protocols error resilience protocol verification algorithm/protocol design and analysis mobile communication systems access schemes

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Shake Well Before Use: Intuitive and Secure Pairing of Mobile Devices

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2009年第6期8卷 792-806页

作者： Mayrhofer, Rene Gellersen, Hans Univ Vienna A-1010 Vienna Austria Univ Lancaster Dept Comp Lancaster LA1 4WA England

A challenge in facilitating spontaneous mobile interactions is to provide pairing methods that are both intuitive and secure. Simultaneous shaking is proposed as a novel and easy-to-use mechanism for pairing of small mobile devices. The underlying principle is to use common movement as a secret that the involved devices share for mutual authentication. We present two concrete methods, ShaVe and ShaCK, in which sensing and analysis of shaking movement is combined with cryptographic protocols for secure authentication. ShaVe is based on initial key exchange followed by exchange and comparison of sensor data for verification of key authenticity. ShaCK, in contrast, is based on matching features extracted from the sensor data to construct a cryptographic key. The classification algorithms used in our approach are shown to robustly separate simultaneous shaking of two devices from other concurrent movement of a pair of devices, with a false negative rate of under 12 percent. A user study confirms that the method is intuitive and easy to use, as users can shake devices in an arbitrary pattern.

关键词： algorithm/protocol design and analysis ubiquitous computing mobile environments authentication human-centered computing mobile applications

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Sum Rate Increase via Variable Interference Protection

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2012年第12期11卷 2121-2132页

作者： Sinanovic, Sinan Burchardt, Harald Haas, Harald Auer, Gunther Univ Edinburgh Sch Engn Inst Digital Commun IDCOM Edinburgh EH9 3JL Midlothian Scotland Univ Edinburgh Joint Res Inst Signal & Image Proc Edinburgh EH9 3JL Midlothian Scotland DOCOMO Commun Labs Europe GmbH Wireless Technol Res D-80687 Munich Germany

The sum rate of spectrum-sharing in decentralized and self-organizing wireless networks is investigated in this paper. Such networks pose the following two fundamental challenges: 1) cochannel interference and 2) the hidden node problem. For a slotted shared wireless medium, where resources are partitioned into time-frequency slots, time-multiplexed receiver initiated busy burst (BB) transmissions solve these problems by establishing an exclusion region around an active receiver by means of receiver feedback. The size of this exclusion region is controlled by an interference threshold that determines whether a user is allowed to transmit on a specific time-frequency resource unit. We propose a novel approach for setting the interference thresholds based on a heuristic derived for a two-link network. First, for two-links, the optimum threshold value is derived that maximizes the sum rate. Second, for multiple links, the new heuristic threshold that only relies on locally available information is derived. It is demonstrated via simulations that heuristic thresholding achieves superior sum rate compared to a fixed system-wide threshold. To complement simulation results, an analytical approach is developed to approximate the probability density function (pdf) of the sum of the interferers in BB setting with fixed threshold with a cumulant-based shifted log normal fitting method.

关键词： Wireless communication algorithm/protocol design and analysis

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On the Multihop Performance of Synchronization Mechanisms in High Propagation Delay Networks

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IEEE TRANSACTIONS ON COMPUTERS 2009年第5期58卷 577-590页

作者： Huang, Pai-Han Desai, Maulik Qiu, Xiaofan Krishnamachari, Bhaskar Univ So Calif Dept Elect Engn Syst Viterbi Sch Engn Los Angeles CA 90089 USA Columbia Univ Dept Elect Engn New York NY 10562 USA Texas Instruments Inc Dallas TX 75206 USA

We analyze the single and multihop performance of time synchronization mechanisms for challenging environments characterized by high propagation delays, low duty-cycle operation, and imprecise clocks, such as underwater acoustic sensor networks. We find that receiver-receiver-based schemes are unsuitable for such environments, and therefore focus primarily on sender-receiver schemes. According to our analysis, a one-way dissemination approach provides good clock skew estimation but poor offset estimation while a two-way exchange approach provides accurate offset estimation but imprecise clock skew estimation. In average, using one-way scheme can result in significant cumulative propagation error over multiple hops, and using two-way can lead to high variance of propagation error. We develop and analyze a hybrid one-way dissemination/two-way exchange technique, and verify the performance of our hybrid scheme through trace-based experiments. The results suggest that this hybrid approach can provide bounded average error propagation in multihop settings and significantly lower variance of propagation error.

关键词： Wireless communications formal models data communications protocol verification sensor networks algorithm/protocol design and analysis

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Improving source routing reliability in mobile ad hoc networks

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2005年第4期16卷 362-373页

作者： Guo, S Yang, O Shu, Y Univ Ottawa Ottawa ON K1N 6N5 Canada Tianjin Univ Tianjin 300073 Peoples R China

In this paper, we propose a novel on-demand routing protocol called Backup Source Routing (BSR) to establish and maintain backup routes that can be utilized after the primary path breaks. The key advantage of BSR is the reduction of the frequency of route discovery flooding, which is recognized as a major overhead in on-demand protocols. We define a new routing metric, called the route reliability, and use it to provide the basis for the backup path selection. We use a heuristic cost function to develop an analytical model and an approximation method to measure this metric. Various algorithms for our BSR protocol in the route discovery phase and route maintenance phase have been designed based on this cost function. Extensive simulations demonstrated that our routing strategy has two interesting features: 1) In less stressful situations of lower mobility, BSR has similar performance to DSR. 2) In more challenging situations of high mobility, BSR can improve the performance significantly.

关键词： mobile communication system wireless communication routing protocol algorithm/protocol design and analysis multihop ad hoc network

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Mathematical evaluation of environmental monitoring estimation error through energy-efficient wireless sensor networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2007年第7期6卷 790-802页

作者： Dardari, Davide Conti, Andrea Buratti, Chiara Verdone, Roberto Univ Bologna Dipartimento Elettron Informat & Sistemist WiLAB I-40136 Bologna Italy CNR IEIITBO I-40136 Bologna Italy Univ Ferrara ENDIF I-44100 Ferrara Italy

In this paper, the estimation of a scalar field over a bidimensional scenario (e.g., the atmospheric pressure in a wide area) through a self-organizing wireless sensor network (WSN) with energy constraints is investigated. The sensor devices (denoted as nodes) are randomly distributed;they transmit samples to a supervisor by using a clustered network. This paper provides a mathematical framework to analyze the interdependent aspects of WSN communication protocol and signal processing design. Channel modelling and connectivity issues, multiple access control and routing, and the role of distributed digital signal processing (DDSP) techniques are accounted for. The possibility that nodes perform DDSP is studied through a distributed compression technique based on signal resampling. The DDSP impact on network energy efficiency is compared through a novel mathematical approach to the case where the processing is performed entirely by the supervisor. The trade-off between energy conservation (i.e., network lifetime) and estimation error is discussed and a design criterion is proposed as well. Comparison to simulation outcomes validates the model. As an example result, the required node density is found as a trade-off between estimation quality and network lifetime for different system parameters and scalar field characteristics. It is shown that both the DDSP technique and the MAC protocol choice have a relevant impact on the performance of a WSN.

关键词： wireless sensor networks modeling techniques algorithm/protocol design and analysis environmental monitoring energy efficiency

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Cooperative Positive Orthogonal Code-Based Forwarding for Multi-Hop Vehicular Networks

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第7期13卷 3914-3925页

作者： Zhang, Le Hassanabadi, Behnam Valaee, Shahrokh Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

Reliable multi-hop forwarding in vehicular networks is required by many critical intelligent transportation system (ITS) safety applications. Cooperative vehicular multi-hop schemes achieve reliability using broadcast transmissions and multiple forwarding relays at each hop. However, packet duplication must be controlled to circumvent the broadcast storm problem. This paper presents the cooperative POC-based forwarding (CPF) protocol for highway vehicular networks, which extends the repetition-based POC-MAC protocol for multi-hop transmissions. At each forwarding hop, multiple cooperating relays form a virtual relay and schedule their transmissions to correspond to a single POC codeword, thereby adhering to the POC-MAC. CPF exploits spatial diversity while mitigating the effect of hidden terminals. By allocating separate POC-based schedules for multi-hop packets and the periodic broadcast of safety heartbeat packets, the CPF protocol reduces the interference between the two. The performance of the CPF protocol is studied through analysis using a Markov model and through ns-2 simulations.

关键词： algorithm/protocol design and analysis wireless communication routing protocols

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Maximizing network lifetime of broadcasting over wireless stationary ad hoc networks

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MOBILE NETWORKS & APPLICATIONS 2005年第6期10卷 879-896页

作者： Kang, I Poovendran, R Univ Washington Dept Elect Engn Seattle WA 98195 USA

We investigate the problem of extending the network lifetime of a single broadcast session over wireless stationary ad hoc networks where the hosts are not mobile. We define the network lifetime as the time from network initialization to the first node failure due to battery depletion. We provide through graph theoretic approaches a polynomial-time globally optimal solution, a variant of the minimum spanning tree (MST), to the problem of maximizing the static network lifetime. We make use of this solution to develop a periodic tree update strategy for effective load balancing and show that a significant gain in network lifetime over the optimal static network lifetime can be achieved. We provide extensive comparative simulation studies on parameters such as update interval and control overhead and investigate their impact on the network lifetime. The simulation results are also compared with an upper bound to the network lifetime.

关键词： broadcast energy efficient routing protocols ad hoc network network topology graphs and networks algorithm/protocol design and analysis

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Performance study of link layer and MAC layer protocols to support TCP in 3G CDMA systems

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2005年第5期4卷 489-501页

作者： Lin, HT Das, SK Univ Texas Dept Comp Sci & Engn Ctr Res Wireless Mobil & Networking Arlington TX 76019 USA

Providing support for TCP with good quality link connection is a key issue for future wireless networks in which Internet access is going to be one of the most important data services. A number of schemes have been proposed in literature to improve the TCP performance over wireless links. In this paper, we study the performance of a particular combination of link layer protocol (e.g., Radio Link protocol or RLP) and MAC retransmissions to support the TCP connections over third generation (3G) wireless CDMA networks. We specifically investigate two metrics - the packet error rate and the delay provided by RLP and MAC retransmissions - both of which are important for TCP performance. For independent and identically distributed (i.i.d) error channels, we propose an analytical model for RLP performance with MAC retransmission. The segmentation of TCP/IP packets into smaller RLP frames, as well as the RLP buffering process, are modeled using a Markov chain. For correlated fading channels, we introduce an analytical metric called RLP retransmission efficiency. We show that: 1) the RLP frame size has significant impact on the overall 3G system performance, 2) MAC layer retransmissions significantly improve the TCP performance, and 3) the RLP retransmission scheme (1,1,1,1,1,1) performs better in highly correlated channels, while scheme (1,2,3) performs better in low correlated channels. Simulation results also confirm these conclusions.

关键词： wireless communication network protocols protocol architecture algorithm/protocol design and analysis modeling techniques

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