Wireless networks have seen tremendous growth recently: wireless communications are available anytime, anywhere perhaps at different Quality-of-Service (QoS) levels. Dense heterogeneous networks can be formed in an ad hoc manner and devices need to coexist and utilize efficiently limited radio resources. This trend is expected to continue towards the forthcoming 5G era (and beyond), where next generation multi-tier cellular networks (consisting of traditional cellular networks, small cell networks, device-to-device networks, etc.) will be the norm and new communication paradigms are expected to arise and be exploited. In general, devices on these networks are expected to be autonomous in the sense of controlling transmission parameters (radio channel, power level) rather than have them dictated by the system. Then, the choices of each device have a direct impact on the performance of (some of) the devices that share the same portion of the spectrum (and the network as whole).
Motivated by the above state of affairs, the fundamental goal of our work is to design efficient distributed radio resource management methods for the smooth deployment of such heterogeneous networks. We focus on two of the most powerful resource allocation methods: power control, i.e., which transmission power a device should choose, and channel access, i.e., when to transmit. After providing a thorough review of the state-of-the-art, we analyse these methods under the prism of game theory, which is a natural choice for modelling scenarios where players with conflicting interests interact with each other. In various emerging wireless networks and under different practical constraints, we formulate games focusing on the solution concept of the Nash Equilibrium (NE). We explore the existence and uniqueness of NE, we devise distributed schemes that converge to them and we study their performance through analysis and simulations. In parallel, we discuss techniques (e.g., bargaining) that may create incentives to the devices to change their transmission parameters leading to operating points that are more efficient than the NE points obtained without these techniques.
In this setting, key problems that we study include the coexistence of small cells and traditional macro cells with different QoS targets, the channel access competition in multihop device-to-device networks (where devices communicate directly without a Base Station or Access Point) and licensed spectrum sharing scenarios, where operators share their spectrum combining power control with bargaining to improve their revenues.
- V.G. Douros, S. Toumpis and G.C. Polyzos, "Channel Access Competition in Linear Multihop Device-to-Device Networks," Proc. International Wireless Communications and Mobile Computing Conference (IWCMC), Nicosia, Cyprus, August 2014. [PDF] [PPTx]
- V.G. Douros, S. Toumpis and G.C. Polyzos, "On the Nash Equilibria of Graphical Games for Channel Access in Multihop Wireless Networks," Proc. Wireless Evolution Beyond 2020 Workshop, in conjunction with IEEE Wireless Communications and Networking Conference (WCNC), Istanbul, Turkey, April 2014. [PDF] [PPTx]
- V.G. Douros, S. Toumpis and G.C. Polyzos, "Power Control Under Best Response Dynamics for Interference Mitigation in a Two-Tier Femtocell Network," Proc. 8th International Workshop on Resource Allocation and Cooperation in Wireless Networks (RAWNET), Paderborn, Germany, May 2012. [PDF] [PPT]
An extended version is available as Technical Report [PDF]
- V.G. Douros and G.C. Polyzos, "Review of Some Fundamental Approaches for Power Control in Wireless Networks," Elsevier Computer Communications, vol. 34, no. 13, pp. 1580-1592, August 2011. [PREPRINT] [Digital Object Identifier-DOI]
- V.G. Douros, G.C. Polyzos and S. Toumpis, "Negotiation-Based Distributed Power Control in Wireless Networks with Autonomous Nodes," Proc. 73rd IEEE Vehicular Technology Conference (VTC2011-Spring), Budapest, Hungary, May 2011. [PDF] [PPT] [DOI]
- V.G. Douros and G.C. Polyzos, "Utility-based power control for interference mitigation in a mixed femtocell-macrocell environment," Proc. 26th Wireless World Research Forum (WWRF26), Doha, Qatar, April 2011. [PDF] [PPT]
- V.G. Douros, G.C. Polyzos and S. Toumpis, "A Bargaining Approach to Power Control in Networks of Autonomous Wireless Entities," Proc. 8th ACM International Symposium on Mobility Management and Wireless Access (MobiWAC), Bodrum, Turkey, October 2010. [PDF] [PPT].
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