Detecting Intelligent Jamming on Physical Broadcast Channel in 5G NR

In fifth generation (5G) new radio (NR), since the synchronization signal blocks are unencrypted during the initial access, an intelligent adversary can detect these signals to obtain the full physical cell identity (PCI) by sniffing, and then use the PCI to attack physical broadcast channel (PBCH) extraction by targeted jamming. Such kind of PBCH intelligent jamming (PBCH-IJ) will cause the failure of the master information block (MIB) decoding, and further result in severe denial of services for those users who want to access this PCI cell. In this letter, we propose to exploit the principal direction of PBCH demodulation reference signal space to detect PBCH-IJ at the user side, which is motivated by the fact that such principal direction under the low mobility scenarios will be significantly impacted if PBCH-IJ happens. Numeric results evaluate and confirm the effectiveness of our detection method.