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Performance Evaluation of Impulse Radio UWB Networks Using Common or Private Acquisition Preambles

IEEE TRANSACTIONS ON MOBILE COMPUTING 2009年第7期8卷 865-879页

作者： Merz, Ruben Le Boudec, Jean-Yves Deutsch Telekom Labs Networking Grp D-10587 Berlin Germany Ecole Polytech Fed Lausanne Sch Comp & Commun Sci CH-1015 Lausanne Switzerland

For impulse-radio ultrawideband (IR-UWB) networks without global synchronization, the first step for correct packet reception is packet detection and timing acquisition: Before recovering the payload of the packet, the destination must detect that the packet is on the medium and determine when exactly the payload begins. Packet detection and timing acquisition rely on the presence of an acquisition preamble at the beginning of each packet. How this preamble is chosen is a network design issue and it may have quite an impact on the network performance. A simple design choice of the network is to use a common acquisition preamble for the whole network. A second design choice is to use an acquisition preamble that is private to each destination. The throughput with the latter choice is likely to be much higher, albeit at the cost of learning the private acquisition preamble of a destination. In this paper, we evaluate how using a common or private acquisition preambles affects the network throughput. Our analysis is based on analytical modeling and simulations. Using our analytical model, we show that a private acquisition preamble yields a tremendous increase in throughput compared to a common acquisition preamble. The throughput difference grows with the number of concurrent transmitters and interferers. This result is confirmed by simulations. Furthermore, additional simulations on multihop topologies with TCP flows demonstrate that a network using private acquisition preambles has a stable throughput. On the contrary, using a common acquisition preamble exhibits the presence of a compounding effect similar to the exposed terminal issue in IEEE 802.11 networks: The throughput is severely degraded and complete flow starvation may occur.

关键词： Ultrawideband impulse radio modeling techniques algorithm/protocol design and analysis

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Bluetooth inquiry time characterization and selection

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第9期5卷 1173-1187页

作者： Peterson, Brian S. Baldwin, Rusty O. Kharoufeh, Jeffrey P. USAF Inst Technol AFIT ENG Dept Elect & Comp Engn Wright Patterson AFB OH 45433 USA

The Bluetooth discovery process requires use of the inquiry substate which not only consumes significant power, but prevents normal data traffic flow and simultaneously acts as a potential noise source for neighboring networks. Therefore, the inquiry substate dwell time should be limited to discovering an acceptable number of neighboring devices. Although an estimate of the probability density function of the time to discover scanning devices is straightforward, the complex temporal and spectral interactions between two devices make precise inquiry time characterization difficult. We characterize these interactions and derive detailed analytical expressions for the probability distribution of the inquiry time for a Bluetooth-enabled device that follows v1.1 of the Bluetooth specification and uses the default 11.25 ms inquiry scan window that opens every 1.28 s. Subsequently, we show a single inquirer will locate 99 percent of all scanning devices within transmission range in 5.12 seconds rather than the 10.24 s recommended in the specification. Using specification v1.2, we show that the inquiry time can be reduced to 3.84 seconds and 1.28 seconds using the standard and interlaced inquiry scan modes, respectively. Substantial inquiry time reduction results in reduced power requirements and increased throughput by increasing data traffic and reducing interference with neighboring piconets. Our results are validated via comparison with existing simulation models and measurement studies. The models used to derive the distribution also lend themselves to characterizing the discovery time with variations in the discovery process.

关键词： mobile computing algorithm/protocol design and analysis mobile communication systems (Bluetooth inquiry probability distribution)

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Security and QoS self-optimization in mobile ad hoc networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2008年第9期7卷 1138-1151页

作者： Shen, ZhengMing Thomas, Johnson P. Oklahoma State Univ Dept Comp Sci Tulsa OK 74106 USA Univ Reading Reading RG6 2AH Berks England Pace Univ New York NY USA

Network quality of service (QoS) and network security have been considered as separate entities and research in these areas have largely proceeded independently. However, security impacts overall QoS and it is therefore essential to consider both security and QoS together when designing protocols for ad hoc environments as one impacts the other. In this paper, we propose a mechanism for a distributed dynamic management system which aims to maximize QoS and/or security while maintaining a minimum user acceptable level of QoS and/or security even as network resource availability changes. In order to achieve this objective, we propose three basic frameworks: a policy-based plug-in security framework, multilayer QoS guided routing, and a proportional, integral, derivative (PID) controller. Simulation results indicate the proposed PID optimized security and the QoS algorithm produces similar performance to nonsecure QoS routing protocols under various traffic loads.

关键词： mobile computing algorithm/protocol design and analysis network-level security and protection

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Rate Adaptation in Congested Wireless Networks through Real-Time Measurements

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2010年第11期9卷 1535-1550页

作者： Acharya, Prashanth A. K. Sharma, Ashish Belding, Elizabeth M. Almeroth, Kevin C. Papagiannaki, Konstantina (Dina) Univ Calif Santa Barbara Dept Comp Sci Santa Barbara CA 93106 USA Intel Res Pittsburgh PA 15213 USA

Rate adaptation is a critical component that impacts the performance of IEEE 802.11 wireless networks. In congested networks, traditional rate adaptation algorithms have been shown to choose lower data-rates for packet transmissions, leading to reduced total network throughput and capacity. A primary reason for this behavior is the lack of real-time congestion measurement techniques that can assist in the identification of congestion-related packet losses in a wireless network. In this work, we first propose two real-time congestion measurement techniques, namely an active probe-based method called Channel Access Delay, and a passive method called Channel Busy Time. We evaluate the two techniques in a testbed network and a large WLAN connected to the Internet. We then present the design and evaluation of Wireless cOngestion Optimized Fallback (WOOF), a rate adaptation scheme that uses congestion measurement to identify congestion-related packet losses. Through simulation and testbed implementation we show that, compared to other well-known rate adaptation algorithms, WOOF achieves up to 300 percent throughput improvement in congested networks.

关键词： Wireless communication access schemes algorithm/protocol design and analysis

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UACAP: A Unified Auxiliary Channel Authentication protocol

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2013年第4期12卷 710-721页

作者： Mayrhofer, Rene Fuss, Juergen Ion, Iulia Univ Appl Sci Upper Austria A-4232 Hagenberg Im Austria Univ Appl Sci Upper Austria Dept Secure Informat Syst A-4232 Hagenberg Im Austria Google Inc Mountain View CA 94043 USA

Authenticating spontaneous interactions between devices and users is challenging for several reasons: the wireless (and therefore invisible) nature of device communication, the heterogeneous nature of devices, and lack of appropriate user interfaces in mobile devices, and the requirement for unobtrusive user interaction. The most promising approach that has been proposed in literature involves the exploitation of the so-called auxiliary channels for authentication to bridge the gap between usability and security. This concept has spawned the independent development of various authentication methods and research prototypes, that, unfortunately, remain hard to compare and interchange and are rarely available to potential application developers. We present a novel, unified cryptographic authentication protocol framework (UACAP) to unify these approaches on using auxiliary channels and analyze its security properties. This protocol and a selection of auxiliary channels aimed at authentication of mobile devices has been implemented and released in an open-source ubiquitous authentication toolkit (OpenUAT). We also present an initial user study evaluating four of these channels.

关键词： Network architecture and design/wireless communication security and protection/authentication information systems applications/miscellaneous algorithm/protocol design and analysis ubiquitous computing mobile environments human-centered computing mobile applications

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Reliable packet transmissions in multipath routed wireless networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2006年第5期5卷 548-559页

作者： Djukic, P Valaee, S Univ Toronto Dept Elect & Comp Engn Toronto ON Canada

We study the problem of using path diversification to provide low probability of packet loss (PPL) in wireless networks. Path diversification uses erasure codes and multiple paths in the network to transmit packets. The source uses Forward Error Correction (FEC) to encode each packet into multiple fragments and transmits the fragments to the destination using multiple disjoint paths. The source uses a load balancing algorithm to determine how many fragments should be transmitted on each path. The destination can reconstruct the packet if it receives a number of fragments equal to or higher than the number of fragments in the original packet. We study the load balancing algorithm in two general cases. In the first case, we assume that no knowledge of the performance along the paths is available at the source. In such a case, the source decomposes traffic uniformly among the paths;we call this case blind load balancing. We show that for low PPL, blind load balancing outperforms single-path transmission. In the second case, we assume that a feedback mechanism periodically provides the source with information about the performance along each path. With that information, the source can optimally distribute the fragments. We show how to distribute the fragments for minimized PPL, and maximized efficiency given a bound on PPL. We evaluate the performance of the scheme through numerical simulations.

关键词： wireless communication fault tolerance network monitoring algorithm/protocol design and analysis linear programming

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Network Coding as a Performance Booster for Concurrent Multi-Path Transfer of Data in Multi-Hop Wireless Networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2017年第4期16卷 1047-1058页

作者： Arianpoo, Nasim Aydin, Ilknur Leung, Victor C. M. Univ British Columbia Dept Elect Engn Vancouver BC V6T 1Z4 Canada Farmingdale State Coll Comp Syst Dept Farmingdale NY 11735 USA

The emerging use of multi-homed wireless devices along with simultaneous multi-path data transfer offers tremendous potentials to improve the capacity of multi-hop wireless networks. The use of simultaneous data transfer over separate disjoint paths in multi-hop wireless networks to increase network capacity is a less explored subject, mainly because of the challenges it triggers for the reliable transport layer protocols. Reliable transport layer protocols generally use packet sequence number as a mean to ensure delivery. As such, the out-of-order packet arrival in reliable transport layer protocols triggers receiver buffer blocking that causes throughput degradation and prevents the reliable multi-path transport layer protocol to realize its vast potential. This paper focuses on integrating network coding with a reliable multi-path transport layer protocol to resolve the receiver buffer blocking problem. We propose an adaptive network coding mechanism to desensitize the receiver against packet reordering and consequently eliminate the receiver buffer blocking problem. Our state-of-the-art network coding scheme uses a combination of Q-learning and logistic regression for rare data events to control the number of redundant packets based on the network dynamics. We confirmed the veracity of our proposed scheme by a queuing theory based mathematical model. Moreover, the effectiveness of the proposed scheme is demonstrated through simulations and testbed experiments.

关键词： Machine learning wireless coding and information theory Markov processes algorithm/protocol design and analysis SCTP-CMT

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Stochastic Power Adaptation with Multiagent Reinforcement Learning for Cognitive Wireless Mesh Networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2013年第11期12卷 2155-2166页

作者： Chen, Xianfu Zhao, Zhifeng Zhang, Honggang VTT Tech Res Ctr Finland FI-90571 Oulu Finland Zhejiang Univ Dept Informat Sci & Elect Engn Hangzhou 310027 Zhejiang Peoples R China

As the scarce spectrum resource is becoming overcrowded, cognitive radio indicates great flexibility to improve the spectrum efficiency by opportunistically accessing the authorized frequency bands. One of the critical challenges for operating such radios in a network is how to efficiently allocate transmission powers and frequency resource among the secondary users (SUs) while satisfying the quality-of-service constraints of the primary users. In this paper, we focus on the noncooperative power allocation problem in cognitive wireless mesh networks formed by a number of clusters with the consideration of energy efficiency. Due to the SUs' dynamic and spontaneous properties, the problem is modeled as a stochastic learning process. We first extend the single-agent Q-learning to a multiuser context, and then propose a conjecture-based multiagent Q-learning algorithm to achieve the optimal transmission strategies with only private and incomplete information. An intelligent SU performs Q-function updates based on the conjecture over the other SUs' stochastic behaviors. This learning algorithm provably converges given certain restrictions that arise during the learning procedure. Simulation experiments are used to verify the performance of our algorithm and demonstrate its effectiveness of improving the energy efficiency.

关键词： Cognitive radio resource allocation algorithm/protocol design and analysis reinforcement learning

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Bandwidth-constrained routing problem in wireless ad hoc networks

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2008年第1期19卷 4-14页

作者： Chiu, Chun-Yuan Kuo, Yu-Liang Wu, Eric Hsiao-Kuang Chen, Gen-Huey Natl Taiwan Univ Dept Comp Sci & Informat Engn Taipei 10764 Taiwan Natl Cent Univ Dept Comp Sci & Informat Engn Chungli 320 Taiwan

The bandwidth-constrained routing problem (BCRP) asks for a route that has sufficient bandwidth for data transmission. When BCRP is defined for wired networks, it can be solved in polynomial time. On the other hand, when it is defined for wireless ad hoc networks, it is NP-complete if the underlying MAC protocol is TDMA-based or CDMA-over-TDMA-based. In this paper, we show that BCRP is still NP-complete, even if CSMA-based or contention-based CDMA MAC protocols are used. Besides, we show that BCRP is polynomial-time solvable if the channel model is collision-free and the scheduling policy is FIFO. In wireless ad hoc networks, no MAC protocol was designed before, which would lead to a polynomial-time solution to BCRP. The results of this paper suggest a design principle for MAC protocols that can support QoS routing well.

关键词： algorithm/protocol design and analysis mobile communication systems reducibility and completeness routing protocols

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An efficient and scalable loss-recovery scheme for video multicast

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IEEE TRANSACTIONS ON MULTIMEDIA 2005年第2期7卷 356-365页

作者： Peng, J Sikdar, B Rensselaer Polytech Inst Dept Elect Comp & Syst Engn Troy NY 12180 USA

With the increased popularity of multimedia services on the Internet, efficient video multicast strategies that can scale easily are of critical importance. This paper addresses the issue of video multicast loss recovery and presents an efficient and scalable scheme: Active Injection Recovery (AIR). The proposed scheme has three distinguishing features: active injection of repair packets into loss regions, on-demand construction of loss-recovery structures, and unique rate control over repair traffic. All of these features can save considerable network resources in a large-scale video multicast session. In addition, the proposed scheme simultaneously meets the three well-known requirements for efficiency and scalability in multicast loss recovery: request suppression, local recovery, and retransmission scoping. Another important feature of the proposed scheme is its low recovery latency, which is essential for video multicast. Our results show that the proposed scheme achieves significantly better overall performance as compared to existing multicast loss recovery schemes.

关键词： algorithm/protocol design and analysis error control loss recovery multicast

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