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Mobile Computing, IEEE Transactions on

Issue 1 • Date Jan-Feb 2004

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Displaying Results 1 - 15 of 15
  • On using peer-to-peer communication in cellular wireless data networks

    Publication Year: 2004 , Page(s): 57 - 72
    Cited by:  Papers (58)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1065 KB) |  | HTML iconHTML  

    A recent class of approaches for enhancing the performance of cellular wireless data networks has focused on improving the underlying network model. It has been shown that using the peer-to-peer network model, a mode of communication typically seen in ad hoc wireless networks, can result in performance improvements such as increased data rate, reduced transmission power, better load balancing, and enhanced network coverage. However, the true impact of adopting the peer-to-peer network model in such an environment is yet to be fully understood. In this paper, we investigate the performance benefits and drawbacks of using the peer-to-peer network model for Internet access in cellular wireless data networks. We find that, although the peer-to-peer network model has significantly better spatial reuse characteristics, the improved spatial reuse does not translate into better throughput performance. Instead, we observe that using the peer-to-peer network model as-is might actually degrade the throughput performance of the network. We identify and discuss the reasons behind these observations. Using the insights gained through the performance evaluations, we then propose two categories of approaches to improve the performance of the peer-to-peer network model: approaches that leverage assistance from the base station and approaches that leverage the relaying capability of multihomed hosts. Through simulation results, we show that using the peer-to-peer network model in cellular wireless data networks is a promising approach when the network model is complemented with appropriate mechanisms. View full abstract»

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  • Self-coordinating localized fair queueing in wireless ad hoc networks

    Publication Year: 2004 , Page(s): 86 - 98
    Cited by:  Papers (38)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1106 KB) |  | HTML iconHTML  

    Distributed fair queueing in a multihop, wireless ad hoc network is challenging for several reasons. First, the wireless channel is shared among multiple contending nodes in a spatial locality. Location-dependent channel contention complicates the fairness notion. Second, the sender of a flow does not have explicit information regarding the contending flows originated from other nodes. Fair queueing over ad hoc networks is a distributed scheduling problem by nature. Finally, the wireless channel capacity is a scarce resource. Spatial channel reuse, i.e., simultaneous transmissions of flows that do not interfere with each other, should be encouraged whenever possible. In this paper, we reexamine the fairness notion in an ad hoc network using a graph-theoretic formulation and extract the fairness requirements that an ad hoc fair queueing algorithm should possess. To meet these requirements, we propose maximize-local-minimum fair queueing (MLM-FQ), a novel distributed packet scheduling algorithm where local schedulers self-coordinate their scheduling decisions and collectively achieve fair bandwidth sharing. We then propose enhanced MLM-FQ (EMLM-FQ) to further improve the spatial channel reuse and limit the impact of inaccurate scheduling information resulted from collisions. EMLM-FQ achieves statistical short-term throughput and delay bounds over the shared wireless channel. Analysis and extensive simulations confirm the effectiveness and efficiency of our self-coordinating localized design in providing global fair channel access in wireless ad hoc networks. View full abstract»

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  • Hierarchical routing overhead in mobile ad hoc networks

    Publication Year: 2004 , Page(s): 46 - 56
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (567 KB) |  | HTML iconHTML  

    Hierarchical techniques have long been known to afford scalability in networks. By summarizing topology detail via a hierarchical map of the network topology, network nodes are able to conserve memory and link resources. Extensive analysis of the memory requirements of hierarchical routing was undertaken in the 1970s. However, there has been little published work that assesses analytically the communication overhead incurred in hierarchical routing. This paper assesses the scalability, with respect to increasing node count, of hierarchical routing in mobile ad hoc networks (MANETs). The performance metric of interest is the number of control packet transmissions per second per node (Φ). To derive an expression for Φ, the components of hierarchical routing that incur overhead as a result of hierarchical cluster formation and location management are identified. It is shown here that Φ is only polylogarithmic in the node count. View full abstract»

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  • Analysis of adaptive bandwidth allocation in wireless networks with multilevel degradable quality of service

    Publication Year: 2004 , Page(s): 5 - 17
    Cited by:  Papers (59)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1591 KB) |  | HTML iconHTML  

    A wireless/mobile network supporting multilevel quality of service (QoS) is considered. In such a network, users or applications can tolerate a certain degree of QoS degradation. Bandwidth allocation to users can, therefore, be adjusted dynamically according to the underlying network condition so as to increase bandwidth utilization and service provider's revenue. However, arbitrary QoS degradation may be unsatisfactory or unacceptable to the users, hence resulting in their subsequent defection. Instead of only focusing on bandwidth utilization or blocking/dropping probability, two new user-perceived QoS metrics, degradation ratio and upgrade/degrade frequency, are proposed. A Markov model is then provided to derive these QoS metrics. Using this model, we evaluate the effects of adaptive bandwidth allocation on user-perceived QoS and show the existence of trade offs between system performance and user-perceived QoS. We also show how to exploit adaptive bandwidth allocation to increase system utilization (for the system administrator) with controlled QoS degradation (for the users). By considering various mobility patterns, the simulation results are shown to match our analytical results, demonstrating the applicability of our analytical model to more general cases. View full abstract»

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  • CLTC: a cluster-based topology control for ad hoc networks

    Publication Year: 2004 , Page(s): 18 - 32
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1618 KB) |  | HTML iconHTML  

    The topology of an ad hoc network has a significant impact on its performance in that a dense topology may induce high interference and low capacity, while a sparse topology is vulnerable to link failure and network partitioning. Topology control aims to maintain a topology that optimizes network performance while minimizing energy consumption. Existing topology control algorithms utilize either a purely centralized or a purely distributed approach. A centralized approach, although able to achieve strong connectivity (k-connectivity for k ≥ 2), suffers from scalability problems. In contrast, a distributed approach, although scalable, lacks strong connectivity guarantees. We propose a hybrid topology control framework, cluster-based topology control (CLTC) that achieves both scalability and strong connectivity. By varying the algorithms utilized in each of the three phases of the framework, a variety of optimization objectives and topological properties can be achieved. In this paper, we present the CLTC framework; describe topology control algorithms based on CLTC and prove that k-connectivity is achieved using those algorithms; analyze the message complexity of an implementation of CLTC, namely, CLTC-A, and present simulation studies that evaluate the effectiveness of CLTC-A for a range of networks. View full abstract»

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  • DESP: a distributed economics-based subcontracting protocol for computation distribution in power-aware mobile ad hoc networks

    Publication Year: 2004 , Page(s): 33 - 45
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1289 KB) |  | HTML iconHTML  

    In this paper, we present a new economics-based power-aware protocol, called the distributed economic subcontracting protocol (DESP) that dynamically distributes task computation among mobile devices in an ad hoc wireless network. Mobile computation devices may be energy buyers, contractors, or subcontractors. Tasks are transferred between devices via distributed bargaining and transactions. When additional energy is required, buyers and contractors negotiate energy prices within their local markets. Contractors and subcontractors spend communication and computation energy to relay or execute buyers' tasks. Buyers pay the negotiated price for this energy. Decision-making algorithms are proposed for buyers, contractors, and subcontractors, each of which has a different optimization goal. We have built a wireless network simulator, called ESIM, to assist in the design and analysis of these algorithms. When the average communication energy required transferring a task is less than the average energy required to execute a task, our experimental results indicate that markets based on our protocol and decision-making algorithms fairly and effectively allocate energy resources among different tasks in both cooperative and competitive scenarios. View full abstract»

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  • Stationary distributions for the random waypoint mobility model

    Publication Year: 2004 , Page(s): 99 - 108
    Cited by:  Papers (180)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (905 KB) |  | HTML iconHTML  

    In simulations of mobile ad hoc networks, the probability distribution governing the movement of the nodes typically varies over time and converges to a "steady-state" distribution, known in the probability literature as the stationary distribution. Some published simulation results ignore this initialization discrepancy. For those results that attempt to account for this discrepancy, the practice is to discard an initial sequence of observations from a simulation in the hope that the remaining values will closely represent the stationary distribution. This approach is inefficient and not always reliable. However, if the initial locations and speeds of the nodes are chosen from the stationary distribution, convergence is immediate and no data need be discarded. We derive the stationary distributions for location, speed, and pause time for the random waypoint mobility model. We then show how to implement the random waypoint mobility model in order to construct more efficient and reliable simulations for mobile ad hoc networks. Simulation results, which verify the correctness of our method, are included. In addition, implementation of our method for the NS-2 simulator is available. View full abstract»

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  • QoS-oriented packet scheduling for wireless multimedia CDMA communications

    Publication Year: 2004 , Page(s): 73 - 85
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (671 KB) |  | HTML iconHTML  

    In the third-generation (and beyond) wireless communication systems, there will be a mixture of different traffic classes, each having its own transmission rate characteristics and quality-of-service (QoS) requirements. In this paper, a QoS-oriented medium access control (MAC) protocol with fair packet loss sharing (FPLS) scheduling is proposed for wireless code-division multiple access (CDMA) communications. The QoS parameters under consideration are the transmission bit error rate (BER), packet loss, and delay requirements. The MAC protocol exploits both time-division and code-division statistical multiplexing. The BER requirements are guaranteed by properly arranging simultaneous packet transmissions and controlling there transmit power levels, whereas the packet loss and delay requirements are guaranteed by proper packet scheduling. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users under the QoS constraints. Simulation results demonstrate effectiveness of the FPLS scheduler, in comparison with other previously proposed scheduling algorithms. View full abstract»

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  • Editorial: state of the transactions

    Publication Year: 2004 , Page(s): 1 - 4
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    Freely Available from IEEE
  • 2003 Reviewers list

    Publication Year: 2004 , Page(s): 109 - 111
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    Freely Available from IEEE
  • IEEE Transactions on Mobile Computing - Table of contents

    Publication Year: 2004 , Page(s): 01
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    Freely Available from IEEE
  • IEEE Trans. on Mobile Computing

    Publication Year: 2004 , Page(s): 0_2
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    Freely Available from IEEE
  • Call for papers

    Publication Year: 2004 , Page(s): 112
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    Freely Available from IEEE
  • Information for authors

    Publication Year: 2004 , Page(s): 03
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    Freely Available from IEEE
  • Cosponsors

    Publication Year: 2004 , Page(s): 0_4
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    Freely Available from IEEE

Aims & Scope

Mobile Computing, as proposed in this Transactions, focuses on the key technical issues related to (a) architectures, (b) support services, (c) algorithm/protocol design and analysis, (d) mobile environments, (e) mobile communication systems, (f) applications, and (g) emerging technologies.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Prasant Mohapatra
Interim Vice-Provost and CIO
Professor, Dept. Computer Science
University of California, Davis, USA
pmohapatra@ucdavis.edu