Non-cooperative spectrum access in cognitive radio networks: A game theoretical model
Non-cooperative spectrum access in cognitive radio networks: A game theoretical model
复制标题
DOI：
10.1016/j.comnet.2011.07.022
复制
发表时间：
2011-12
期刊：
影响因子：
--
通讯作者：
J. Elias;F. Martignon;A. Capone;E. Altman
中科院分区：
文献类型：
--
作者：
J. Elias;F. Martignon;A. Capone;E. Altman
认知无线网络提供了与许可（主要）用户以机会方式共享无线信道的能力。主用用户具有某一频段的操作许可；它们的访问只能由主运营商控制，不受任何其他未授权（次要）用户的影响。另一方面，从用户没有频谱许可证，他们试图利用主用户空闲的频谱间隙。本文从博弈论的角度研究了认知无线电网络中的频谱接入问题。该问题被建模为一个非合作频谱接入博弈，次要用户同时接入主用户剩余的多个可用频谱，并在考虑可用频谱上的拥塞程度的情况下优化其目标函数。作为对现有作品的一个关键创新特征，我们准确地模拟了单元之间的干扰，捕捉了空间再利用的效果。此外，我们考虑了非弹性和弹性用户流量，以模拟实时和数据传输应用程序。最后，我们考虑了频谱接入问题的另一种表述，其中参与者使用复制因子动态来调整他们的策略，我们推导了纳什平衡点的收敛条件。我们证明了纳什均衡的存在性，并推导了均衡流设置。最后，给出了几种认知无线电场景下频谱接入博弈的数值结果，并研究了单元间的干扰对博弈效率的影响。我们的研究结果表明，本文提出的拥塞成本函数在所有考虑的网络场景中导致纳什均衡和最优解之间的差距很小，从而代表了设计定价机制以获得网络的社会最优使用的起点。
Cognitive radio networks provide the capability to share the wireless channel with licensed (primary) users in an opportunistic manner. Primary users have a license to operate in a certain spectrum band; their access can only be controlled by the primary operator and is not affected by any other unlicensed (secondary) user. On the other hand, secondary users (SUs) have no spectrum license, and they attempt to exploit the spectral gaps left free by primary users. This work studies the spectrum access problem in cognitive radio networks from a game theoretical perspective. The problem is modeled as a non-cooperative spectrum access game where secondary users access simultaneously multiple spectrum bands left available by primary users, optimizing their objective function which takes into account the congestion level observed on the available spectrum bands. As a key innovative feature with respect to existing works, we model accurately the interference between SUs, capturing the effect of spatial reuse. Furthermore, we consider both non-elastic and elastic user traffic, to model real-time as well as data transfer applications. Finally, we consider an alternative formulation of the spectrum access problem, where players use replicator dynamics to adjust their strategies, and we derive convergence conditions to Nash equilibrium points. We demonstrate the existence of the Nash equilibrium, and derive equilibrium flow settings. Finally, we provide numerical results of the proposed spectrum access game in several cognitive radio scenarios, and study the impact of the interference between SUs on the game efficiency. Our results indicate that the congestion cost functions we propose in this paper lead to small gaps between Nash equilibria and optimal solutions in all the considered network scenarios, thus representing a starting point for designing pricing mechanisms so as to obtain a socially optimal use of the network.