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Selfish Dynamic Spectrum Access in Multichannel Wireless Networks: Complete and incomplete information analysis
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.
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The increasing popularity and widespread deployment of wireless data systems fuel the increasing demand for more spectrum. On the other hand, various studies measuring spectrum utilization show that there is a huge variation in spectrum utilization at different times and locations. In view of this, various dynamic spectrum access (DSA) methods have been proposed in order to achieve more efficient utilization of spectrum resources by virtue of exploiting the variations in spectrum demand over time and space. Implementing DSA systems in a centralized way can lead to complexity and scalability problems due to the extensive control signaling involved. Therefore distributed implementations of DSA systems in which the users can access the system resources at their own discretion have been proposed. These distributed mechanisms typically incorporate cognitive radio systems which act as agents on behalf of users to measure the radio environment and make decisions based on these measurements. On the other hand, the freedom of the users in distributed systems to form their actions can lead each user to try to maximize its benefit from the system without regard the overall performance of the DSA system. Therefore, selfish behavior can prevail in distributed systems, which is likely to degrade the system performance.In this thesis we investigate the implications of selfish decision making in dynamic spectrum access systems. To address this broad problem, we focus our analysis on a particular system which can represent the essential properties of DSA systems and thus can shed light on the performance of the broad class of DSA systems with selfish users. Specifically, we model a DSA system as a multichannel random access system which uses ALOHA for medium access, and we analyze the behavior of the selfish users by modeling the system as a non-cooperative game. In this analysis we incorporate the effect of channel state information on the decision making of the users; we consider both cases when the users act on global (complete) and on local (incomplete) information. We determine the behavior of the selfish users at the Nash equilibria of the non-cooperative game and measure the performance of the system in terms of sum and individual utilities for various user loads and amount of available resources. We try to identify how the performance of the DSA system with selfish users compares with its cooperative counterpart. By performing these analyses we provide insights into the broader question of whether selfish users can utilize spectrum resources in a DSA system as well as cooperative users.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. , xi, 109 p.
Series
Trita-ICT-COS, ISSN 1653-6347 ; 1108
Keyword [en]
Game theory, Multichannel random access, Bayesian game, Nash equilibrium Heterogeneous channels
National Category
Telecommunications Communication Systems
Research subject
SRA - ICT
Identifiers
URN: urn:nbn:se:kth:diva-50738OAI: oai:DiVA.org:kth-50738DiVA: diva2:462581
Presentation
2011-12-14, Sal C1, Electrum 1, Isafjordsgatan 26, Kista, Stockholm, 14:00 (English)
Opponent
Supervisors
Projects
MultiOperator Dynamic Spectrum access (MODyS)
Funder
Wireless@kth
Note

QC 20111208

Available from: 2011-12-08 Created: 2011-12-07 Last updated: 2013-11-08Bibliographically approved
List of papers
1. Distributed multichannel random access networks with selfish users
Open this publication in new window or tab >>Distributed multichannel random access networks with selfish users
2010 (English)In: Proceedings of the Fifth International Conference on Cognitive Radio Oriented Wireless Networks Communications (CROWNCOM), 2010, 2010, 5577687- p.Conference paper, Published paper (Refereed)
Abstract [en]

Dynamic spectrum access (DSA) schemes allow the users to share spectrum resources by taking advantage of the variations in spectrum demand over time and space. Carrying out dynamic spectrum allocation centrally, however, can be a complex task. For this reason, distributed schemes in which users can access the available channels independently may be preferable to centralized DSA schemes. Cognitive radio systems, which enable user terminals to sense their environment and form their action accordingly, are particularly well-suited for distributed systems. On the other hand, the freedom in distributed schemes gives the users the option to act selfishly, which has decisive effects on system performance. In this paper we consider a distributed multichannel wireless random access system where users selfishly access the channels in the system. We analyze the behavior of the selfish users by modeling the system as a non-cooperative game and we identify all stable operating points (Nash equilibria) of this game. We then compare the performance of this system with a number of cooperative distributed DSA schemes in terms of user utilities. Our results show that the performance of the selfish multichannel random access system can be comparable to cooperative schemes.

Keyword
Cognitive radio, Complex task, Cooperative schemes, Distributed schemes, Distributed systems, Dynamic spectrum access, Dynamic spectrum allocations, Multi-channel, Multichannel random access, Nash equilibria, Noncooperative game, Operating points, Random access systems, Selfish users, Spectrum demand, Time and space, User terminals, User utility
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:kth:diva-50683 (URN)10.4108/ICST.CROWNCOM2010.9284 (DOI)2-s2.0-77958165163 (Scopus ID)978-1-4244-5885-1 (ISBN)
Conference
2010 5th International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CROWNCom 2010; Cannes; France; 9 June 2010 through 11 June 2010
Note

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
2. Distributed Dynamic Spectrum Access in Multichannel Random Access Networks with Selfish Users
Open this publication in new window or tab >>Distributed Dynamic Spectrum Access in Multichannel Random Access Networks with Selfish Users
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
Keyword
Cognitive radio, Communications Society, Cooperative systems, Degradation, Game theory, Narrowband, Nash equilibrium, Resource management, Space technology, System performance
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:kth:diva-50684 (URN)10.1109/WCNC.2010.5506420 (DOI)000299203101103 ()2-s2.0-77955027345 (Scopus ID)978-1-4244-6396-1 (ISBN)
Conference
Wireless Communications and Networking Conference (WCNC), 2010
Note

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
3. Selfish multi-channel random access in heterogeneous channels
Open this publication in new window or tab >>Selfish multi-channel random access in heterogeneous channels
(English)Manuscript (preprint) (Other academic)
Abstract [en]

We analyze the behavior of selfish users in a multichannel random access system in which the propagation characteristics of the available channels in the system exhibit different statistics. We formulate the behavior of the selfish users as a Bayesian game and identify the transmission strategies at the Nash equilibria. Following this, we propose a simple iterative algorithm to obtain the transmission probabilities of the selfish uses at the Nash equilibria and investigate the convergence properties of this algorithm. Using the transmission probabilities of the selfish users at the Nash equilibria, we analyze the performance of the MRA system with selfish users in terms of sum and per-user utilities and compare this system with its cooperative and scheduling system counterparts. We find that selfish behavior results in significant performance loss compared to scheduling and cooperative systems, which increases as the system load increases.

National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:kth:diva-51071 (URN)
Note

QC 20120328

Available from: 2011-12-09 Created: 2011-12-09 Last updated: 2016-06-20Bibliographically approved

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