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  • 1.
    Chaltseva, Anna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Network state estimation in wireless multi-hop networks2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Multi-hop wireless networks in general and those built upon IEEE 802.11 standard in particular are known for their highly dynamic and unstable performance. The commonly accepted way for improving the situation is to jointly optimize the performance of protocols across different communications layers. Being able to characterize a state of the network is essential to enable the cross-layer optimization. This licentiate thesis investigates methods for passive characterization of network state at medium access control and transport layers based on information accessible from the corresponding layers below.Firstly, the thesis investigates a possibility for characterizing traffic intensity relying solely on the statistics of measurements from the physical layer. An advantage of this method is that it does not require decoding of the captured packets, by this accounting for the effect from long-range interferences introduced by transmissions at the border of the communication range of a receiver.Secondly, a question of predicting TCP throughput over a multi-hop wireless path is addressed. The proposed predictor is a practically usable function of statistically significant parameters at transport, medium access control and physical communication layers. The presented model is able to predict the TCP throughput with 99% accuracy, which provides an essential input for various cross-layer optimization processes.Finally, during the course of the experimental work the issues of accuracy of simulation-based modeling of communication processes were investigated. The thesis is concluded by presenting a comparative study of the performance characteristics measured in a single channel multi-hop wireless network test-bed and the corresponding measurements obtained from popular network simulators ns-2 and ns-3 when configured with identical settings. The thesis presents the evaluation of the mismatch between the results obtained in the test-bed and the simulators with their standard empirical radio models.

  • 2.
    Chaltseva, Anna
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Empirical cross-layer model of TCP throughput in multihop wireless chain2010Rapport (Annet vitenskapelig)
    Abstract [en]

    Analysis of TCP throughput in multihop wireless networks is a continuously important research topic. Yet a neat and practically useful formula for the TCP transfer rate similar to the macroscopic model of TCP in the Internet, however, capturing the cross-layer dependencies is unavailable for wireless networks. In this paper we statistically analyze the significance of parameters on physical, MAC and transport layers in a multihop wireless chains and derive a practically usable cross-layer throughput formula. The resulting model allows estimation of the throughput with less than 2% error.

  • 3.
    Chaltseva, Anna
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Empirical predictor of TCP throughput on a multihop wireless path2010Inngår i: Smart spaces and next generation Wired/Wireless networking: third Conference on Smart Spaces, ruSMART 2010, and 10th international conference, NEW2AN 2010, St. Petersburg, Russia, August 23-25, 2010 ; proceedings / [ed] Sergey Balandin; Roman Dunaytsev; Yevgeni Koucheryavy, Encyclopedia of Global Archaeology/Springer Verlag, 2010, s. 323-334Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses a question of predicting TCP throughput over a multihop wireless path. Since it is useful for a variety of applications it is desirable that TCP throughput prediction technique introduces low-overhead while avoiding active measurement techniques. Analytical derivation of the throughput predictor for multihop wireless networks is difficult if not impossible at all due to complex cross-layer dependencies. In this article we statistically analyze the significance of parameters on physical, MAC and transport layers in a multihop wireless chain and empirically derive a practically usable throughput predictor. The resulting model allows prediction of the throughput with less than 2% error.

  • 4.
    Chaltseva, Anna
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    On passive characterization of aggregated traffic in wireless networks2011Rapport (Annet vitenskapelig)
    Abstract [en]

    We present a practical measurement-based model of aggregated traffic intensity on microseconds time scale for wireless networks. The model allows estimating the traffic intensity for the period of time required to transmit data structures of different size (short control frames and a data packet of the maximum size). The presented model opens a possibility to mitigate the effect of interferences in the network by optimizing the communication parameters of the MAC layer (e.g. size of contention window, retransmission strategy, etc.) for the forthcoming transmission to minimize the packet collision probability and further increase network's capacity. We also discuss issues and challenges associated with PHY-layer characterization of the network state.

  • 5.
    Chaltseva, Anna
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    On passive characterization of aggregated traffic in wireless networks2012Inngår i: Wired/Wireless Internet Communication: 10th International Conference, WWIC 2012, Proceedings, New York: Encyclopedia of Global Archaeology/Springer Verlag, 2012, s. 282-289Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present a practical measurement-based characterization of the aggregated traffic on microseconds time scale in wireless networks. The model allows estimating the channel utilization for the period of time required to transmit data structures of different sizes (short control frames and a data packet of the maximum size). The presented model opens a possibility to mitigate the effect of interferences in the network by optimizing the communication parameters of the MAC layer (e.g. the size of contention window, retransmission strategy, etc.) for the forthcoming transmission. The article discusses issues and challenges associated with the PHY-layer characterization of the network state.

  • 6. Granlund, Daniel
    et al.
    Gylling, Arne
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, CDT.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Jacquier, Anna
    Elkotob, Muslim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, CDT.
    Åhl, Anneli
    Project: BASICNET2008Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Broadband Access Services In Converging NETworks

  • 7.
    Khattak, Rabiullah
    et al.
    Luleå tekniska universitet.
    Chaltseva, Anna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Riliskis, Laurynas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Comparison of wireless network simulators with multihop wireless network testbed in corridor environment2011Inngår i: Wired/wireless internet communications: 9th IFIP TC 6 International Conference, WWIC 2011, Vilanova i la Geltrú, Spain, June 15-17, 2011 ; proceedings / [ed] Xavier Masip-Bruin, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2011, s. 80-91Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a comparative study between results of a single channel multihop wireless network testbed and the network simulators ns-2 and ns-3. We explore how well these simulators reflect reality with their standard empirical radio modeling capabilities. The environment studied is a corridor causing wave-guiding propagation phenomena of radio waves, which challenges the radio models used in the simulators. We find that simulations are roughly matching with testbed results for single flows, but clearly deviate from testbed results for concurrent flows. The mismatch between simulations and testbed results is due to imperfect wireless propagation channel modeling. This paper reveals the importance of validating simulation results when studying single channel multihop wireless network performance. It further emphasizes the need for validation when using empirical radio modeling for more complex environments such as corridors.

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