Concatenated Cluster Delay Line Channel Modelling in Ris-Assisted 6G Wireless Communication Systems

A Cluster Delay Line (CDL) is an advanced, more realistic, and accurate wireless channel model as per 3GPP standards, particularly for mmWave frequency bands. In simulating a complex multipath wireless signal propagation, CDL channel model represents scattered multipath signals as into logical groups called 'clusters' of delayed versions. The multipath signals are from different reflecting surfaces where each signal with a specific delay. In this paper, we generate a 6 G waveform and transmit through a reconfigurable intelligent surfaces (RIS)-assisted channel and evaluate the received signal strength along with its signal constellation. It models the two channels using CDL channels, i.e. between base station (BS) to RIS and RIS to user equipment (UE). In the absence of line of sight (LOS) path, the RIS-assisted channel is simulated using CDL channel model and an algorithm is proposed to control and optimize the phase of individual reflecting elements of RIS through iterative process. This work also models RIS scattering losses and channel path losses with stochastic models. The received signal-to-noise ratio (SNR) and the path loss are evaluated at 4 GHz-42 GHz frequency bands for different modulation schemes.