System Performance of Outband D2D Gateway for Wireless Sensor Networks

The application of device-to-device (D2D) technology has increased recently to cover various types of communication networks due to its potential improvements in system throughput and energy efficiency. The integration between D2D and Wireless Sensor Networks (WSN) in the Unlicensed spectrum (D2D-U), allows D2D users to transmit and receive on the unlicensed spectrum, i.e., outband. This enable D2D users to work as a gateway for the WSN networks to collect the data from sensors nodes and forward it to another D2D user or base station. Moreover, in D2D-U networks, D2D users can share the licensed spectrum, i.e., inband, with the existing cellular users as well as sharing the unlicensed spectrum with WSN networks. In this paper, within the framework of D2D-U and the duty cycle-based unlicensed spectrum access, we propose the application of the auction algorithm to minimize the overall interference that cellular and WSN nodes suffer from the D2D communications while guaranteeing the signal-to-noise-and-interference ratio requirements of all these heterogeneous users. Theoretical analysis and numerical simulation show that the use of unlicensed spectrum can significantly reduce interference by D2D users on both cellular users and WSN nodes.