Multicell Topology

In system-level simulations with 3GPP channel modeling, it is customary to place cells on a spiral hexagonal grid. The grid is defined by the inter-site distance, determining the distance between any two adjacent hexagonal cell centers, and the number of rings of the grid, typically 1 or 2 (corresponding to 7 and 19 cells, hence 21 and 57 base stations, respectively).

To eliminate edge effects that would result in users at the cell borders experiencing reduced interference levels, the grid is usually wrapped around to create a seamless topology.

To learn how to place base stations and drop users on a hexagonal grid in Sionna, refer to the Hexagonal Grid Topology notebook.

Hexagon(radius, coord[, coord_type, ...])	Class defining a hexagon placed in a hexagonal grid.
HexGrid(num_rings[, cell_radius, ...])	Creates a hexagonal spiral grid of cells, drops users uniformly at random and computes wraparound distances and base station positions.
gen_hexgrid_topology(batch_size, num_rings, ...)	Generates a batch of topologies with hexagonal cells placed on a spiral grid, 3 base stations per cell, and user terminals (UT) dropped uniformly at random across the cells.
get_num_hex_in_grid(num_rings)	Computes the number of hexagons in a spiral hexagonal grid with a given number of rings \(N\).
convert_hex_coord(coord, conversion_type[, ...])	Converts the center coordinates of a hexagon within a grid between any two of the types {"offset", "axial", "euclid"}.