Physical layer security in heterogeneous cellular network

The heterogeneous cellular network is believed to be a promising deployment of cellular networks in 5G. This chapter comprehensively studies physical layer security in a multitier HCN where BSs, authorized users and eavesdroppers are all randomly located. We first propose a truncated average received signal power-based secrecy mobile association policy. Under this policy, we investigate and provide tractable expressions for the connection probability and secrecy probability of a randomly located user. We further evaluate the network-wide secrecy throughput and the minimum secrecy throughput per user under both connection and secrecy probability constraints. We prove that the proposed mobile association policy significantly enhances the secrecy throughput performance of the HCN.