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Personal Communications, IEEE

Issue 1 • Date Feb. 2001

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Displaying Results 1 - 9 of 9
  • Author Index

    Publication Year: 2001 , Page(s): 72 - 74
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  • Subject index

    Publication Year: 2001 , Page(s): 74 - 80
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  • On the relaying capability of next-generation GSM cellular networks

    Publication Year: 2001 , Page(s): 40 - 47
    Cited by:  Papers (111)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    The latest developments and experimentation in mobile ad hoc networks show that MANETs will be an alternative candidate in many private and public multimedia networks. Current interest in MANET systems has grown considerably because they can rapidly and economically extend the boundaries of any terrestrial network; integrating MANET and GSM offers a great number of benefits (e.g., increasing capacity, improving coverage) at the cost of increasing the complexity of the mobile terminal and its battery consumption. The objective of this article is to address new concepts in the GSM system, dealing with both standardized features as well as theoretically and technologically feasible improvements, which contribute to evolutionary changes in general. Dynamic evolution of GSM presents a platform for Universal Mobile Telecommunication System introduction and major trends in GSM development are addressed, in particular progress towards a generic platform to accommodate relaying capability in GSM cellular networks. A GSM simulation tool has been constructed for quantifying the integrated system characteristics View full abstract»

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  • Technology advances from Small Unit Operations Situation Awareness System development

    Publication Year: 2001 , Page(s): 30 - 33
    Cited by:  Papers (4)  |  Patents (1)
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    The SUO SAS system is developing new technologies that have the potential of significantly advancing the use of personal communications systems. Technologies being developed offer more capable ad hoc networking to accommodate large numbers of mobile users, higher performance modems, and protocols that maintain link connectivity in adverse environments, and increased flexibility for spectral utilization View full abstract»

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  • Geographical routing using partial information for wireless ad hoc networks

    Publication Year: 2001 , Page(s): 48 - 57
    Cited by:  Papers (122)  |  Patents (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    We present an algorithm for routing in wireless ad hoc networks using information about the geographical location of the nodes. We assume each node knows its geographical position and the position of the node to which it wants to send a packet. Initially, the nodes know only their neighbors. But over time they discover other nodes in the network. The routing table at a node S is a list <(pi,Si)>, where pi is a geographical position and Si is a neighbor of node S. When node S receives a packet for a node D at position pos(D), it finds the p i in its routing table which is closest to pos(D) and forwards the packet to the neighbor Si. We prove the correctness of the algorithm and show that our algorithm naturally aggregates the nodes so that the routing tables remain small. We show that the mean routing table size is O(L¯logn), where L¯ is the average number of hops between two nodes and n is the number of nodes in the network. We also present methods for taking positional errors, node failures and mobility into account. We justify the results through simulation View full abstract»

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  • A feedback-based scheme for improving TCP performance in ad hoc wireless networks

    Publication Year: 2001 , Page(s): 34 - 39
    Cited by:  Papers (71)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (104 KB)  

    Ad hoc networks are completely wireless networks of mobile hosts, in which the topology rapidly changes due to the movement of mobile hosts. This frequent topology change may lead to sudden packet losses and delays. Transport protocols like TCP, which have been designed for reliable fixed networks, misinterpret this packet loss as congestion and invoke congestion control, leading to unnecessary retransmissions and loss of throughput. To overcome this problem, a feedback scheme is proposed so that the source can distinguish between a route failure and network congestion. When a route is disrupted, the source is sent a route failure notification packet, allowing it to invalidate its timers and stop sending packets. When the route is reestablished, the source is informed through a route reestablishment notification packet, upon which it resumes packet transmissions. Simulation experiments show that in the event of route failures, as the route reestablishment time increases, the use of feedback provides significant improvements in performance View full abstract»

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  • IrDA-VFIr (16 Mb/s): modulation code and system design

    Publication Year: 2001 , Page(s): 58 - 71
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    Devices for convenient information exchange over the wireless infrared channel are commonly found in many of today's mobile platforms for computing, communicating, and imaging. Most devices comply with the international standards promoted by the Infrared Data Association for data rates of up to 4 Mb/s. With the approval of a 16 Mb/s data rate option called Very Fast Infrared, IrDA's point-to-point usage model is extendable to applications requiring wireless connectivity beyond 4 Mb/s. We describe the design and the properties of a new modulation code specifically developed for VFIr, and discuss related system design aspects. After defining basic system requirements and modulation constraints imposed by the WIrC, we introduce a rate-2/3 run-length-limited code designed to meet these criteria. The Boolean expressions for encoding and decoding are given, and their implementation is discussed together with various aspects of system design such as scrambling, invalid sequence detection, and error propagation. Furthermore, it is shown that the specific composite nature of the new RLL modulation code enables simple and efficient generation of VFIr packet frames by encoding an equivalent packet frame assembled entirely in the code's input data domain View full abstract»

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  • Performance comparison of two on-demand routing protocols for ad hoc networks

    Publication Year: 2001 , Page(s): 16 - 28
    Cited by:  Papers (265)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Ad hoc networks are characterized by multihop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols. We compare the performance of two prominent on-demand routing protocols for mobile ad hoc networks: dynamic source routing (DSR) and ad hoc on-demand distance vector routing (AODV). A detailed simulation model with MAC and physical layer models is used to study interlayer interactions and their performance implications. We demonstrate that even though DSR and AODV share similar on-demand behavior, the differences in the protocol mechanics can lead to significant performance differentials. The performance differentials are analyzed using varying network load, mobility, and network size. Based on the observations, we make recommendations about how the performance of either protocol can be improved View full abstract»

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  • Lessons from a full-scale multihop wireless ad hoc network testbed

    Publication Year: 2001 , Page(s): 8 - 15
    Cited by:  Papers (65)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    This article describes our experiences building a multihop wireless ad hoc network of eight nodes driving around a 700 m by 300 m site. Each node runs the dynamic source routing protocol and interfaces seamlessly with existing Internet infrastructure and the Mobile IP protocol. We present quantitative results from data collected during runs of our testbed under a composite workload including voice, bulk data, and real-time data. Based on careful analysis of our data, we highlight radio propagation issues that network protocols will need to address in the future View full abstract»

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Aims & Scope

This Magazine ceased publication in 2001. The current retitled publication is IEEE Wireless Communications.

Full Aims & Scope