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Distributed Dynamic Spectrum Access in Multichannel Random Access Networks with Selfish Users
KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.ORCID iD: 0000-0003-4986-6123
2010 (English)In: Wireless Communications and Networking Conference (WCNC), 2010 IEEE, IEEE , 2010, 1-6 p.Conference paper, Published paper (Refereed)
Abstract [en]

Dynamic spectrum allocation schemes enable users to share spectrum resources by exploiting the variations in spectrum demand over time and space. Performing dynamic spectrum allocation centrally can be prohibitively complex. Therefore distributed schemes in which users can access the available channels independently may be preferable to centralized allocation. However, in distributed dynamic spectrum access, the lack of central coordination makes it difficult to utilize the system resources efficiently. Furthermore, if some or all of the users decide to deviate selfishly from the commonly agreed access procedure, this may have a decisive effect on system performance. In this paper we investigate the effect of incomplete information and selfish behavior on system performance in wireless access systems. We extend previous work by studying a distributed multichannel wireless random access system. Using a game-theoretic approach, we analyze the behavior of users in the selfish system and derive the transmission strategies at the Nash equilibrium. Our results show that lack of information leads to substantial degredation in performance of cooperative systems. We also show that there is a large incentive for selfish behavior in such cooperative systems. Selfish behavior of all users, however, causes further performance degradation, particularly in high load settings.

Place, publisher, year, edition, pages
IEEE , 2010. 1-6 p.
Keyword [en]
Cognitive radio, Communications Society, Cooperative systems, Degradation, Game theory, Narrowband, Nash equilibrium, Resource management, Space technology, System performance
National Category
Telecommunications Communication Systems
URN: urn:nbn:se:kth:diva-50684DOI: 10.1109/WCNC.2010.5506420ISI: 000299203101103Scopus ID: 2-s2.0-77955027345ISBN: 978-1-4244-6396-1 (print)OAI: diva2:462401
Wireless Communications and Networking Conference (WCNC), 2010

QC 20111208. © 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. QC 20111207

Available from: 2011-12-07 Created: 2011-12-07 Last updated: 2014-10-20Bibliographically approved
In thesis
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2. Capacity analysis of densely deployed wireless LANs
Open this publication in new window or tab >>Capacity analysis of densely deployed wireless LANs
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wireless LANs (WLANs) based on the IEEE 802.11 standard have become an integral part of today’s indoor wireless communication infrastructure. As WLAN deployments become more prevalent and densely deployed, the nodes in these WLANs start to create congestion and interference with each other. This congestion and interference fundamentally limits the performance of these coexisting WLANs. We analyze the capacity limits of such densely deployed WLANs.

We begin our analysis by investigating the suitability of the attributes of WLANs, namely their cooperative operation based on locally available information, for indoor high-capacity wireless access provisioning. We compare the cooperative class of wireless systems with another class of systems whose users behave selfishly. Following this qualitative assessment, we perform a detailed, qualitative analysis of the capacity of densely deployed WLANs in terms of a number of key environmental and operational parameters. The indoor propagation environment has a significant influence on the congestion and interference that these coexisting WLANs exert on each other. Therefore we investigate the impact of propagation environment on the aggregate throughput of densely deployed WLANs. As WLANs are deployed in close proximity of each other, the transmissions in one WLAN start to influence the outcome of transmissions in other WLANs. The manner in which the access points are deployed, and the manner in which stations associate themselves with the available access points around themselves is shown to be an influential factor in the performance of these coexisting WLANs. Therefore, we investigate the impact of random versus planned access point deployment on performance of densely deployed WLANs. Similarly, we investigate the impact of stations associating with the access point with the strongest signal or with another sufficiently strong access point in their vicinity. Furthermore, we investigate the throughput of densely deployed WLANs when operating with bounded delay. More specifically we examine the case when the input traffic arriving at the transmitters are expected to reach their destination within a certain time period, thus the transmit queues cannot grow without bounded and the system should operate at a stable point.

The indoor propagation environment, creates complex interference relationships between nodes in coexisting WLANs.These complex interference relationships are compounded by the node interactions dictated by the nonlinear algorithms in the IEEE 802.11 MAC protocol, thus the problem of estimating the performance of these coexisting WLANs by means of simple analytical models becomes difficult. In contrast, detailed packet level simulations provide accurate performance estimates, although such analyses are computationally expensive. Therefore we seek to provide a model to estimate the throughput of densely deployed WLANs based on empirical throughput results of detailed simulations of such densely deployed WLANs. In addition, in our effort to develop an empirical throughput model for densely deployed WLANs, we develop a measure which we call “cell congestion” to be able to order and compare different propagation environments, and an “effective density” concept which accounts for the influence of the propagation environment on the congestion and interference experienced by a WLAN deployment of a given density. We expect these concepts to be useful in improving the operation of WLANs to be able to meet the predicted increase in demand for capacity.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. x, 91 p.
TRITA-ICT-COS, ISSN 1653-6347 ; 1410
National Category
Communication Systems
urn:nbn:se:kth:diva-154343 (URN)
Public defence
2014-10-24, Sal A, Electrum 1, KTH, Isafjordsgatan 26, Stockholm, 14:00 (English)

QC 20141020

Available from: 2014-10-20 Created: 2014-10-17 Last updated: 2014-10-23Bibliographically approved

Open Access in DiVA

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