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.

The 3GPP TR 38.901 calibration helpers additionally provide the indoor-office and indoor-factory drops used by the InH and InF channel models. Their results are tuple-compatible and can be passed directly to the corresponding set_topology method. The indoor-factory helper returns an IndoorFactoryTopology, which also records the resolved InF sub-scenario and hall dimensions. For non-default hall dimensions, configure InF with this metadata and call topology.set_topology(channel_model) to validate the channel-statistics geometry before applying the deployment.

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.
IndoorFactoryTopology(values, ...[, ...])	Tuple-compatible indoor-factory topology with InF configuration metadata.
gen_hexgrid_topology(batch_size, num_rings, ...)	Generates UMi/UMa/RMa hexagonal-grid topologies using Tables 7.2-1 and 7.2-3 of [TR38901V1920].
gen_tr38901_multicell_topology(scenario, ...)	Generates a TR 38.901 multi-cell topology using Tables 7.8-1 and 7.8-2 for UMi/UMa and Table 7.2-3 for RMa of [TR38901V1920].
gen_tr38901_indoor_office_topology(...[, ...])	Generates a TR 38.901 indoor-office topology using Tables 7.2-2 and 7.8-1 of [TR38901V1920].
gen_tr38901_indoor_factory_topology(...[, ...])	Generates a TR 38.901 indoor-factory topology using Tables 7.2-4 and 7.8-7 of [TR38901V1920].
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"}.