Why are cell sites often represented by hexes?
Q. Why are cell sites often represented by hexes?
A. This shape dates back to the original cellular radio memorandum written by Young and Ring of Bell Labs. Among other things it discusses in print for the first time, the idea of frequency reuse in a small zone system. You can download a copy of this important 1947 paper by clicking here.
Take a look a the graphic below, from that paper. In this example there are nine sets of frequencies. See how the center of each cell site lines up to form a hex? It was then a natural thing to depict smaller areas as hexes. Also note how the same frequency set is never used in an adjacent cell. This idea applied to all cellular radio schemes until Qualcomm's CDMA based system (IS-95) allowed all frequencies to be used in all cells, greatly increasing capacity.
Be cautioned! Cell sites do not lie at the center of each cell, as you might think from this illustration. Read the excerpt from this IEEE interview (external link) below to see why cell sites transmitt to the inside of a cell, not the outside:
Hochfelder: Going back to your work at Bell Labs, you mentioned Phil Porter and Dick Frenkiel as two people you worked with to develop the idea for first generation mobile telephones. Would you tell me a ittle about them? I’d also like to hear about any other talented engineers that you worked with at Bell Labs.
Engel: There were very many talented engineers, and I’ll only be able to mention a few. . . Phil Porter never got the credit he deserved. Many of the features in system we developed were his brainchild. In most radio systems, the transmitter is at the center of the coverage area, radiating in all directions, and when people thought of cellular systems with hexagons they thought of the same thing. Phil came up with the concept of putting the base stations at the corners of the cells with directional antennas aiming inward. That gives further isolation from the other antennas, the other cells further away, and that’s the way they’re all built these days. That is only one of his innovations.
Hochfelder: Simple, yet brilliant.