Securing Uplink Transmission for Lightweight Single-Antenna UEs in the Presence of a Massive MIMO Eavesdropper

With the coming of the Internet of Things (IoT) and the fifth generation (5G) wireless communication era, more and more lightweight user equipments (UEs) appear in our life. The private information they gather and transmit on the uplink will likely face security risks, since the lightweight UEs are probably with limited number of antennas, e.g., only one antenna, limited power and low signal processing and data computing capabilities, which may inherently weaken the corresponding secrecy performance. As a consequence, traditional cryptographic techniques and complex physical layer security techniques with favorable secrecy performance may not be suitable for lightweight UEs due to high implementation complexity. Moreover, it is highly plausible that the unauthorized nodes can utilize much more powerful large antenna array, i.e., massive multiple-input multiple-output (MIMO) technology, to intercept the uplink information sent by the lightweight UEs due to the maturity of massive MIMO technology by then. Considering the possibility of facing massive MIMO eavesdropper, we propose to adopt the uplink original symbol phase rotated (UOSPR) scheme to secure the uplink transmission for lightweight single-antenna UEs in this paper. By employing the UOSPR secure transmission scheme, the lightweight UEs will randomly rotate the original information bearing symbols before they are transmitted to the BS on the uplink. This can be viewed as a symbol encryption process. The BS is then assured to be able to infer the accurate phase rotation and recover the original symbols while the massive MIMO eavesdropper can learn little useful information about the randomly rotated phase. The corresponding secrecy analysis of the UOSPR scheme on the uplink transmission is presented in detail. Furthermore, we show that the UOSPR scheme is with low complexity from the perspective of the lightweight UEs, which potentially makes it a candidate uplink secure transmission scheme in IoT and 5G scenarios. Simulation results are provided to further corroborate the effectiveness of the UOSPR secure transmission scheme.