Sectors, Cells, Multi-Beam Technology in Cellular Coverage Systems
Apr 08, 2016
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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I hate to say it when I can’t understand something but that’s the case here. Some of your blogs take complicated concepts and turn them into easy-to-understand ones, but I’m completely lost here. I detect something about improving cellular coverage here, but that’s about as far as I got. Ha ha.
I am plunging into a distributed antennae systems (DAS) as a PM. One problem I am having understanding this technology is in fact the notion of “sectoring” as it pertains to an in-building base-transceiver-station (BTS). The BTS when used in a DAS network connects the carrier’s network (via incoming fiber to the BTS) to the DAS headend facility onsite in the building. The DAS headend combines the incoming signals and distributes the over the in-building DAS network using a distribution network consisting of CWDM muxes, fiber, remote radios, coax, and ceiling mounted antennaes. A carrier-neutral configuration is setup to process incoming signals from 4 major carriers with distribution to campus buildings that eventually cover about 8500 employees. Each headend can manage up to 64 outgoing ports that connect to the remote radio units spread throughout the buildings that transfer (bi-directionally) the signal to the various remote radio units. My problem is that I have a system that needs 110 ports and therefore I am wondering if a 2-sectored BTS solves my problem by providing me with 128 output ports.
This may sound ridiculous, but I’ve actually heard of cell sectoring in cellular networks. Just about everyone would agree our cellular carriers don’t give us the speed, clarity of calls, and connectivity we truly desire. However, I can understand a cellular system architecture has to keep up with our changing times (which translates into “Give me more” when it comes to cell phone power) and it’s encouraging to hear of things like sectored directional antennas and sector panel antennas being used and tweak to maximize the signals we get. I imagine the combination of this and a good cell phone booster will satisfy my hunger for more data and call power.
I knew cell phone carriers had odd ways of mapping out their networks, but this helps me understand things better, particularly in terms of using antennas to strengthen the cell phone signals. There are cell phone boosters and there are DAS installations that use a specifically designed array of antennas to power up signals, correct? I like how there are different signals too including directional, etc. It sounds like this gives people a number of strategies to make sure they can get clear cell phone calls and avoid dropped calls.
What exactly is cellular radio? I’m confused about this term. Is it something different than cell phones? Is it something that could be enhanced by a cell phone booster or is it something that would be enhanced by a DAS installation?