Security and Communication Networks

Research Article

Geometry-Based Stochastic Model and Statistical Characteristic Analysis of Cell-Free Massive MIMO Channels

The specific process to establish a GBSM.

	Step 1: Take the q-th AP and user as the centers of circles to establish a double-ring model. Take the center of the connection line as the center of the sphere to establish a hemisphere model and Cartesian coordinate system.
	Step 2: Randomly generate the distribution of scatterers, generate AAoD/EAoD/AAoA/EAoA for each single scattering path and double scattering path, and calculate the distance of each path.
	Step 3: Obtain the time delays , , and for each LoS path, single scattering path, and double scattering path.
	Step 4: Allocate the normalized power coefficients and for the single scattering path and double scattering path, respectively.
	Step 5: Combine Step 2–Step 4 to obtain the normalized channel expression, i.e., , between the q-th AP p-th antenna and user.
	Step 6: Repeat Step 1–Step 5 to build the channel matrix .