RIS-Assisted Scheduling for High-Speed Railway Secure Communications

With the rapid development of high-speed railway systems and wireless communication, application ultra-wideband millimeter wave band is an inevitable trend. However, channel has large propagation loss easy to be blocked. Moreover, there are many problems such as eavesdropping between base station (BS) train. As emerging technology, reconfigurable intelligent surface (RIS) can achieve effect passive beamforming by controlling incident electromagnetic in desired direction. We propose a RIS-assisted scheduling scheme for interrupt flows improving quality service (QoS). In propsed scheme, RIS deployed BS multiple mobile relays (MRs). By jointly optimizing vector discrete phase shift RIS, constructive interference direct link signals reflected achieved, capacity eavesdroppers guaranteed within controllable range. Finally, purpose maximizing number successfully scheduled satisfying their QoS requirements practically realized. Extensive simulations demonstrate that proposed superior performance regarding completed system secrecy over four baseline schemes literature.