2 research outputs found
Reconfigurable Intelligent Surface Assisted High-Speed Train Communications: Coverage Performance Analysis and Placement Optimization
Reconfigurable intelligent surface (RIS) emerges as an efficient and
promising technology for the next wireless generation networks and has
attracted a lot of attention owing to the capability of extending wireless
coverage by reflecting signals toward targeted receivers. In this paper, we
consider a RIS-assisted high-speed train (HST) communication system to enhance
wireless coverage and improve coverage probability. First, coverage performance
of the downlink single-input-single-output system is investigated, and the
closed-form expression of coverage probability is derived. Moreover, travel
distance maximization problem is formulated to facilitate RIS discrete phase
design and RIS placement optimization, which is subject to coverage probability
constraint. Simulation results validate that better coverage performance and
higher travel distance can be achieved with deployment of RIS. The impacts of
some key system parameters including transmission power, signal-to-noise ratio
threshold, number of RIS elements, number of RIS quantization bits, horizontal
distance between base station and RIS, and speed of HST on system performance
are investigated. In addition, it is found that RIS can well improve coverage
probability with limited power consumption for HST communications.Comment: 14 figures, accepted by IEEE Transactions on Vehicular Technolog