Data transmission system for multiplexing a plurality of pieces of data in a layered division multiplexing (ldm) method and transmitting multiplexed data, reception device used in the data transmission system, and data transmission method therefor

Abstract

[Problem] To propose a technology capable of appropriately demodulating, in a receiving device, a plurality of pieces of data multiplexed through the quasi-synchronous LDM method. [Solution] A transmission device generates a UL modulated signal by using an IFFT process of Npoints, generates an LL modulated signal by using an IFFT process of Npoints different from the Npoints, and transmits signals obtained by timing-adjusting the modulated signals such that the start timings thereof coincide with each other in a predetermined cycle, and combining the timing-adjusted signals at a predetermined power ratio. In addition, the receiving device performs an Npoint FFT process on the reception signal from the transmitting device, reproduces UL and generates UL reception replica, on the basis of the result, and performs an Npoint FFT process on a signal obtained by subtracting the UL reception replica from the reception signal, and reproduces LL on the basis of the result.