When discussing cellular radio, a basic hexagon is used to symbolize a complex object, which in this case is the physical area capable of being covered by cellular radio antennas. These hexagonal areas are known as "cells". Using a hexagonal shape allows us to visualize the idea of cells on a map, because the idea is to show an area, without gaps, that is completely covered by radio.
We know there will be coverage gaps in a cellular system, but using a hexagonal shape allows us to clearly see how the system is laid out, if only in theory. A "cell site" is a point or location that gives radio coverage to a cell, whereas the cell is the geographical, or physical, area.
Illustration at the top shows the cell structure. We don’t refer to a "three-sectored cell" - We now refer to the three cells connected to one base station, where each is a sector. Each cell is denoted by its own hexagon, rather than the three cells being enclosed in one hexagon. This means that, in a three-sector situation, cells and sectors are the same thing. In the future, there will be challenges to this "sectors and cells" terminology with the implementation of new antenna technology for systems like 4G and LTE.
The concept of optimizing capacity and coverage with an antenna system is dependent upon concentrating the beam in certain areas and adjusting to a user's equipment, which by nature are not uniformly located. The even distribution of a user's equipment would obviously support the notion of the structure and same cell size of the hexagon honeycomb. However, with today’s technologies like beam tilt, beams are altered to be different directions and sizes in order to support real user patterns.
Multi-beam technologies (which are used in six-sector deployments), active antennas, and adaptive array, mean that the coverage area of antennas can be formed and shaped to fit the coverage and capacity requirements of users.
So, whether a six-sector deployment is actually two sectors per cell or not, suggests that we shouldn't be too concerned about defining a sector or a cell. Instead, we should be focusing on both the size and beam-shape of the antenna, and how effectively it handles user coverage and covers the environment.
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