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The design and evaluation of unified cellular and ad hoc networks

IEEE TRANSACTIONS ON MOBILE COMPUTING 2007年第9期6卷 1060-1074页

作者： Luo, Haiyun Meng, Xiaqiao Ramjee, Ram Sinha, Prasun Li, Li (Erran) Univ Illinois Dept Comp Sci Urbana IL 61801 USA NEC Labs Amer Auton Survivable Distributed Syst Grp Princeton NJ 08540 USA Bell Labs Murray Hill NJ 07974 USA Ohio State Univ Dept Comp Sci & Engn Columbus OH 43210 USA

In third-generation (3G) wireless data networks, providing service to low data-rate users is required for maintaining fairness, but at the cost of reducing the cell's aggregate throughput. In this paper, we propose the Unified Cellular and Ad Hoc Network (UCAN) architecture for enhancing cell throughput while maintaining fairness. In UCAN, a mobile client has both 3G interface and IEEE 802.11-based peer-to-peer links. The 3G base station forwards packets for destination clients with poor channel quality to proxy clients with better channel quality. The proxy clients then use an ad hoc network composed of other mobile clients and IEEE 802.11 wireless links to forward the packets to the appropriate destinations, thereby improving cell throughput. We refine the 3G base station scheduling algorithm so that the throughput gains are distributed in proportion to users' average channel rates, thereby maintaining fairness. With the UCAN architecture in place, we propose novel greedy and on-demand protocols for proxy discovery and ad hoc routing that explicitly leverage the existence of the 3G infrastructure to reduce complexity and improve reliability. We further propose secure crediting mechanisms to motivate users that are not actively receiving to participate in relaying packets for others. Through both analysis and extensive simulations with HDR and IEEE 802.11b, we show that the UCAN architecture can increase individual user's throughput by more than 100 percent and the aggregate throughput of the HDR downlink by up to 50 percent.

关键词： wireless algorithm/protocol design and analysis mobile communication systems

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Adaptive application-driven WLAN power management

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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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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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Impact of human mobility on opportunistic forwarding algorithms

Impact of human mobility on opportunistic forwarding algorit...

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IEEE INFOCOM 2006 Conference/25th IEEE International Conference on Computer Communications

作者： Chaintreau, Augustin Hui, Pan Crowcroft, Jon Diot, Christophe Gass, Richard Scott, James Thomson Res F-92648 Boulogne France Univ Cambridge Cambridge CB3 0FD England Microsoft Res Cambridge CB3 0FB England Intel Res Pittsburgh PA 15213 USA

We study data transfer opportunities between wireless devices carried by humans. We observe that the distribution of the intercontact time (the time gap separating two contacts between the same pair of devices) may be well approximated by a power law over the range [10 minutes;1 day]. This observation is confirmed using eight distinct experimental data sets. It is at odds with the exponential decay implied by the most commonly used mobility models. In this paper, we study how this newly uncovered characteristic of human mobility impacts one class of forwarding algorithms previously proposed. We use a simplified model based on the renewal theory to study how the parameters of the distribution impact the performance in terms of the delivery delay of these algorithms. We make recommendations for the design of well-founded opportunistic forwarding algorithms in the context of human-carried devices.

关键词： computer systems organization communication/networking and information technology mobile computing algorithm/protocol design and analysis mobile environments mathematics of computing probability and statistics

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Impact of human mobility on opportunistic forwarding algorithms

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2007年第6期6卷 606-620页

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Cluster Overlay Broadcast (COB): MANET routing with complexity polynomial in source-destination distance

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第6期5卷 653-667页

作者： Ritchie, L Yang, HS Richa, AW Reisslein, M Arizona State Univ Dept Elect Engn Goldwater Ctr Tempe AZ 85287 USA Kyungnam Univ Div Elect & Elect Engn Masan 631701 South Korea Arizona State Univ Dept Comp Sci & Engn Tempe AZ 85287 USA

Routing algorithms with time and message complexities that are provably low and independent of the total number of nodes in the network are essential for the design and operation of very large scale wireless mobile ad hoc networks (MANETs). In this paper, we develop and analyze Cluster Overlay Broadcast (COB), a low-complexity routing algorithm for MANETs. COB runs on top of a one-hop cluster cover of the network, which can be created and maintained using, for instance, the Least Cluster Change (LCC) algorithm. We formally prove that the LCC algorithm maintains a cluster cover with a constant density of cluster leaders with minimal update cost. COB discovers routes by flooding (broadcasting) route requests through the network of cluster leaders with a doubling radius technique. Building on the constant density property of the network of cluster leaders, we formally prove that, if there exists a route from a source to a destination node with a minimum hop count of Delta, then COB discovers a route with at most O(Delta) hops from the source to the destination node in at most O(Delta) time and by sending at most O(Delta(2)) messages. We prove this result for arbitrary node distributions and mobility patterns and also show that COB adapts asymptotically optimally to the mobility of the nodes. In our simulation experiments, we examine the network layer performance of COB, compare it with Dynamic Source Routing, and investigate the impact of the MAC layer on COB routing.

关键词： one-hop clustering algorithm/protocol design and analysis message complexity routing protocol scalability time complexity wireless mobile ad hoc network

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Energy and spatial reuse efficient network-wide real-time data broadcasting in mobile ad hoc networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第10期5卷 1297-1312页

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

In this paper, we present NB-TRACE, which is an energy-efficient network-wide voice broadcasting architecture for mobile ad hoc networks. In the NB-TRACE architecture, the network is organized into overlapping clusters through a distributed algorithm, where the clusterheads create a nonconnected dominating set. Channel access is regulated through a distributed TDMA scheme maintained by the clusterheads. The first group of packets of a broadcast session is broadcast through flooding, where each data rebroadcast is preceded by an acknowledgment to the upstream node. Nodes that do not get an acknowledgment for a predetermined time, except the clusterheads, cease to rebroadcast, which prunes the redundant retransmissions. The connected dominating set formed through this basic algorithm is broken in time due to node mobility. The network responds to the broken links through multiple mechanisms to ensure the maintenance of the connected dominating set. We compare NB-TRACE with four network layer broadcast routing algorithms ( Flooding, Gossiping, Counter-based broadcasting, and Distance-based broadcasting) and three medium access control protocols ( IEEE 802.11, SMAC, and MH-TRACE) through extensive ns-2 simulations. Our results show that NB-TRACE outperforms other network/MAC layer combinations in minimizing energy dissipation and optimizing spatial reuse, while producing competitive QoS performance.

关键词： low-power design energy-aware systems data communications distributed protocols network communications network topology wireless communication network protocols protocol architecture protocol verification routing protocols access schemes mobile computing algorithm/protocol design and analysis mobile communication systems

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Bandwidth aggregation for real-time applications in heterogeneous wireless networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第4期5卷 388-403页

作者： Chebrolu, K Rao, RR Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

A variety of wireless interfaces are available for today's mobile user to access Internet content. When coverage areas of these different technologies overlap, a terminal equipped with multiple interfaces can use them simultaneously to improve the performance of its applications. In this paper, we motivate the advantages that can be had through simultaneous use of multiple interfaces and present a network layer architecture that enables diverse multiaccess services. In particular, we explore in depth one such service provided by the architecture: Bandwidth Aggregation (BAG) for real-time applications. An important aspect of the architecture when providing BAG services for real-time applications is the scheduling algorithm that partitions the traffic onto different interfaces such that the QoS requirements of the application are met. We propose one such algorithm Earliest Delivery Path First (EDPF), that ensures packets meet their playback deadlines by scheduling packets based on the estimated delivery time of the packets. We show through analysis that EDPF performs close to an idealized Aggregated Single Link (ASL) discipline, where the multiple interfaces are replaced by a single interface with same aggregated bandwidth. A prototype implementation and extensive simulations carried using video and delay traces show the performance improvement BAG with EDPF scheduling offers over using just the Highest Bandwidth Interface (HBI) and other scheduling approaches based on weighted round robin.

关键词： network architecture and design video scheduling algorithm/protocol design and analysis implementation simulation

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A theory of network localization

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第12期5卷 1663-1678页

作者： Aspnes, James Eren, Tolga Goldenberg, David K. Morse, A. Stephen Whiteley, Walter Yang, Yang Richard Anderson, Brian D. O. Belhumeur, Peter N. Yale Univ Dept Comp Sci New Haven CT 06520 USA Yale Univ Dept Elect Engn Lab Control Sci & Engn New Haven CT 06520 USA York Univ Dept Math & Stat N York ON M3J 1P3 Canada Natl ICT Australia Ltd Canberra ACT 2601 Australia Columbia Univ Dept Comp Sci New York NY 10029 USA

In this paper, we provide a theoretical foundation for the problem of network localization in which some nodes know their locations and other nodes determine their locations by measuring the distances to their neighbors. We construct grounded graphs to model network localization and apply graph rigidity theory to test the conditions for unique localizability and to construct uniquely localizable networks. We further study the computational complexity of network localization and investigate a subclass of grounded graphs where localization can be computed efficiently. We conclude with a discussion of localization in sensor networks where the sensors are placed randomly.

关键词： computer systems organization communication/networking and IT mobile computing algorithm/protocol design and analysis architectures theory of computation analysis of algorithms and problem complexity nonnumerical algorithms and problems geometrical problems and computation mathematics of computing discrete mathematics graph theory network problems computer applications mobile applications location-dependent and sensitive wireless sensor networks

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Optimal resource allocation in overlay multicast

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2006年第8期17卷 808-823页

作者： Cui, Yi Xue, Yuan Nahrstedt, Klara Vanderbilt Univ Dept Elect Engn & Comp Sci Nashville TN 37325 USA Univ Illinois Dept Comp Sci Urbana IL 61801 USA

Although initially proposed as the deployable alternative to IP multicast, the overlay network actually revolutionizes the way network applications can be built. In this paper, we study the rate allocation problem in overlay-based multirate multicast, which can be understood as a utility-based resource allocation problem. Each receiver is associated with a utility defined as a function of its streaming rate. Our goal is to maximize the aggregate utility of all receivers, subject to network capacity constraint and data constraint. The latter constraint is unique in overlay multicast, mainly due to the dual role of end hosts as both receivers and senders. We use a price-based approach to address this problem. Two types of prices, network price and data price, are generated with regard to the two constraints of the problem. A distributed algorithm is proposed, where each receiver adjusts its flow rate according to the associated network price and data price. The algorithm is proved to converge to the optimal point, where the aggregate utility of all receivers is maximized. We implement our algorithm using an end-host-based protocol. Our protocol purely relies on the coordination of end hosts to accomplish tasks originally assigned to network routers, which makes it directly deployable to the existing network infrastructure.

关键词： multicast algorithm/protocol design and analysis nonlinear programming

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