NeTS: Small: Dynamic Spectrum Access under Uncertainty: Theory, Algorithm Development, and Evaluation

对无线频谱的需求预计将在未来继续增长，这只会加剧目前感受到的频谱紧张。将无线频谱的独家和永久使用权授予承租人的严格许可政策进一步加剧了这种稀缺。著名的2002年FCC研究已经发现了这一缺陷，该研究估计，根据时间和地点的不同，许可频谱的利用率在15-85%之间，因此，强调了对频谱共享新方法的迫切需要。由于用户流量需求、频谱可用性、无线信道条件和用户位置等固有的不确定性，这些新方法的开发非常具有挑战性，称为动态频谱接入（DSA）技术。因此，该项目的首要目标是在存在这些不确定性的情况下有效地管理动态频谱访问。在这个项目中开发的算法最终鼓励联邦和商业频谱持有者参与DSA系统。额外的无线带宽正在被释放出来，用于将基本服务迁移到无线领域，这大大降低了目前被排除在这个市场之外的很大一部分人访问无线网络的成本。这些新兴系统还创造了新的基于通信的商业模式，开发了社区资源，并改善了公共安全。管理动态频谱接入面临以下三个主要挑战：(1)从二级提供商/用户的角度来看，频谱资源的动态性和可能的相关性；(2)频谱可用性在长期信道统计和实时信道状态方面的不确定性；(3)二次流量的不确定性和二次用户的异构性能/定价需求。本课题设计了有效的信息共享、频谱感知和调度策略。由于上述三个维度的联合优化是一项艰巨的挑战，因此该项目分为两个相互关联的重点。在第一个推力中，假设给定的频谱不确定性水平，并为二级提供商设计有效的调度策略以满足各种QoS需求。在第二部分中，考虑了二级供应商通过协调单元感知信道来控制信息不准确性的情况，并研究了联合感知和调度问题。所开发的算法通过仿真和测试平台实现进行了验证。通过发展结合随机优化、近似算法和博弈论的分析技术来研究不确定性的影响。所得到的联合感知和资源分配策略具有低复杂度和可证明的效率。该项目将吸引代表性不足的学生和K-12学生。

The demand for wireless spectrum is projected to continue growing well into the future, and will only worsen the currently felt spectrum crunch. Rigid licensing policies that give exclusive and permanent right of use of wireless spectrum to lessees further exacerbate this scarcity. This shortcoming has been identified in the famous 2002 FCC study, which estimates the utilization of licensed spectrum between 15-85% depending on time and location, thus, underscoring the critical need for new methods of spectrum sharing. Development of these new methods, coined as Dynamic Spectrum Access (DSA) techniques, is very challenging due to the inherent uncertainty in user traffic demand, spectrum availability, wireless channel conditions, and user locations. Thus, the overarching goal of this project is to efficiently manage dynamic spectrum access in the presence of these uncertainties. The algorithms developed in this project ultimately encourage both federal and commercial spectrum holders to participate in DSA systems. Additional wireless bandwidth is being freed up for essential services to be migrated to the wireless domain, significantly lowering the cost of access to wireless networks for a significant fraction of the society currently shut out of this market. These emerging systems also create new communication-based business models, develop community resources, and improve public safety.Managing dynamic spectrum access faces three major challenges induced by: (1) the dynamics and the possibly correlated nature of spectrum resource from a secondary provider/user's perspective; (2) uncertainty about spectrum availability in terms of long-term channel statistics and real-time channel states; (3) uncertainty of secondary traffic and heterogeneous performance/pricing requirements of secondary users. In this project, efficient information sharing, spectrum sensing, and scheduling policies are designed that take all these three aspects into account. Since jointly optimizing across the three dimensions outlined above is a daunting challenge, the project is organized across two inter-related thrusts. In the first thrust, a given level of spectrum uncertainty is assumed, and efficient scheduling policies are designed for a secondary provider to meet various QoS requirements. In the second thrust, the case where a secondary provider can control information inaccuracy by coordinating SUs to sense channels is considered and the joint sensing and scheduling problem investigated. The developed algorithms are validated through simulations and via testbed implementations. The effect of uncertainties is investigated by developing analytical techniques that combine stochastic optimization, approximation algorithms and game theory. The resulting joint sensing and resource allocation policies are low-complexity and provably efficient. This project will engage underrepresented students and K-12 students.