Internet of Things (IoT) is considered as the future network to support machine-to-machine communications. To realize IoT network, a large number of IoT devices need to be deployed, which will lead a problem of allocating sufficient spectrum for the rapidly increasing devices. Through cooperative spectrum sharing, the unlicensed IoT devises (UIDs) help forward the signal of primary users (PUs) to exchange for dedicated spectrum to transmit their signals, which can effectively improve the spectrum utilization for the IoT network. However, UIDs are selfish and rational. They may not be willing to take participate in the cooperative spectrum sharing after considering the potential costs. It is necessary to provide effective incentives to encourage them to take part in the cooperative spectrum sharing. In this paper, we use contract theory to model the incentive mechanism in OFDM-based cognitive IoT network under a practical scenario with incomplete information, where UIDs’ private information (i.e., transmission cost and wireless channel characteristics) are not known by PUs. By using contract theory, the negotiations between PUs and UIDs are modeled as a labor market, where PUs and UIDs act as the employer and employees, respectively. We first study the optimal contract design to maximize PUs’ utility as well as the social welfare, in which the contract consists of a menu of expected signal-to-ratios and payments over each subcarrier. Then, we propose heuristic UIDs’ selection method with a finite PUs’ budget. Finally, simulation results demonstrate the efficiency of our proposed contract design and UIDs selection method.

中文翻译：

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基于激励机制的OFDM认知物联网网络协作频谱共享

物联网 (IoT) 被认为是支持机器对机器通信的未来网络。为了实现物联网网络，需要部署大量的物联网设备，这将导致为快速增长的设备分配足够频谱的问题。通过协作频谱共享，免许可的物联网设备（UID）帮助转发主用户（PU）的信号以交换专用频谱来传输他们的信号，这可以有效地提高物联网网络的频谱利用率。然而，UID 是自私和理性的。考虑到潜在成本后，他们可能不愿意参与合作频谱共享。有必要提供有效的激励措施，鼓励他们参与合作频谱共享。在本文中，我们使用契约理论对基于 OFDM 的认知物联网网络中的激励机制进行建模，该网络在信息不完整的实际场景中，其中 PU 不知道 UID 的私有信息（即传输成本和无线信道特性）。通过使用合同理论，PU 和 UID 之间的谈判被建模为劳动力市场，其中 PU 和 UID 分别充当雇主和雇员。我们首先研究了使 PU 的效用和社会福利最大化的最佳合同设计，其中合同由每个子载波上的预期信号比和付款菜单组成。然后，我们提出了具有有限 PU 预算的启发式 UID 选择方法。最后，仿真结果证明了我们提出的合同设计和 UID 选择方法的效率。