Mobility-based Physical-layer Key Generation Scheme for D2D Communications Underlaying Cellular Network

Due to extreme confidentiality and low computational load, physical-layer key has set off a revolution in security encryption. However, existing physical layer-key key researches rarely pay attention to the potential value of speed in random source selection. In this paper, we take the mobility characteristics of D2D devices as a random source to design physical-layer key. First of all, we establish a uniform scattering environment model in the cellular network and analyze the impact of D2D device’s speed on the parameters of the wireless channel. On this basis, we propose a mobility-based physical-layer key generation scheme and use Gaussian random vector for key extraction and analysis. Then, we analyze the performance of our scheme, derive the expressions such as key capacity and average key length(ASKL), and compare them with existing solutions through simulation. Finally, the relative results confirm the theoretical derivation and the advantages of our scheme.