Research on Coverage Enhancement of Narrowband M2M Communications Based on Unlicensed Spectrum

It can be seen that Machine-to-Machine (M2M) devices will be widely deployed in the near future. However, because of the scarce spectrum, it is difficult to support such a large number of devices only depending on the licensed spectrum. On the contrary, unlicensed spectrums are a better choice for many enterprises which prefer to build M2M networks independently. In this paper, we present a narrowband M2M communications system on the unlicensed spectrum (U-NB-M2M). The key principles of the system design are reduced energy consumption, low complexity, high feasibility and reliability. In addition, this article provides several schemes on how to improve the coverage of our proposed M2M system. An experimental platform is built to evaluate the performance of the proposed system by various metrics and the simulation results prove that our proposed schemes achieve significant coverage enhancement.