Know the base station
As the most numerous mobile communication devices, base stations are almost everywhere.
However, base stations come in many different types.
The antenna of the base station is also divided into many types.
Really distinguishable people?
Actually not much.
â–¼ Imagine this scene â–¼
When you and your partner walk hand in hand on the road (provided you have one), a base station appears in the distance.
You tell her (or him):
"Look! That’s a China Mobile 4G TD-LTE Directional Polarized Smart Antenna for Three-Sector Base Station."
What the hell? How high is the battle!
Deeply hidden, there is wood! ! !
Imagine the worship of your partner. There are also passersby's horror and praise.
You are simply a godly existence!
If you don’t want to be late, start quickly!
What is a "base station"?
Base station, or Base Station, is generally referred to as the "public mobile communication base station."
Everyone knows that the base station provides signals to the mobile phone.
â–¼ For example, Dongdong â–¼
But in fact, the above is just an iron tower and an antenna — just an integral part of the base station.
In addition to these visible parts, the base station also includes many invisible components.
In the 2G and 3G era, the base station was divided into two layers, as shown below:
By the 4G LTE era, it was streamlined into one layer, becoming a separate eNodeB.
Take eNodeB as an example. It generally includes the following components:
The names are smooth and easy to remember: BBU = 哔哔哟, RRU = ah ah åµ, Antenna feed = antenna + feeder.
BBU
The image below shows the front view of the BBU.
At first glance, it looks like something that can't be rained on. So, usually, the BBU is placed indoors (in the machine room).
About the computer room, you need to explain: The base station usually has a computer room. Some are in an inconspicuous corner of the building, while others are outdoors, like the one below.
Field base station room (pheasant) â–¼
Everyone usually sees such a small house under the tower.
I specifically found a wild station and took a real photo â–¼
(A bit like the Millennium Tomb...)
The former base station was built by the operator. Not very troublesome. Now it's changed to an integrated station.
That’s it ▼
Bring your own base, find a place to put it, and you're done. (Some even bring their own wheels, you can pull them away.)
What do you ask me in the computer room? No key, can't get in...
I can only find an online photo. Probably like this â–¼
(Most of the computer rooms are not so clean, spacious, and bright...)
Back to topic
BBU is stuffed in the cabinet of the machine room.
There may be cabinet power supply and transmission equipment in the cabinet. Very easy to identify: There are a lot of red, black, and blue lines (power cords), with many switches. Generally, power supply equipment. There are many fiber ports and network ports, plugged in a lot of yellow fiber optic lines, generally transmission equipment.
After talking for a long time, what is the BBU doing?
BBU — Building Baseband Unit, baseband processing unit. Mainly complete channel codec, baseband signal modulation and demodulation, protocol processing, etc.
It doesn't matter if you don't understand, PASS!
RRU
Next talk about RRU.
â–¼This is RRUâ–¼
Is it a bit like a radiator and a suitcase?
Don't underestimate it. This stuff is especially heavy. I tried a person to move it. As a result, the old waist was flashed.
But I heard that the RRU is now lighter.
RRU — Radio Remote Unit. Mainly completes the RF signal modulation and demodulation, RF analog signal power amplification, and transmission to the antenna.
RRU is mainly pole or wall mounted.
â–¼Holding rod installation â–¼
â–¼ Wall mounting â–¼
Forgot to say, BBU occasionally hangs on the wall, saving space. Unlike the BBU, the RRU is installed outdoors.
Antenna system
Next is the antenna feed. Antennas include antennas and feeders. Everyone often mentions "antenna," but the base station antenna may not be what you think.
The most used antenna now is this kind of â–¼
It’s a board, so it’s also called a “plate antenna.†Very easy to install by pole. Also saves money and space. A pillar is fixed. A “board†is a sector. It belongs to directional antenna. Usually installed at a high position with the board facing the direction of coverage. Will tilt down a certain angle.
The following figure is a standard three-sector base station.
(I found the RRU installed on the pole below the antenna?)
There are many types of antennas... According to the wavelength: medium wave antenna, short wave antenna, ultra short wave antenna, microwave antenna... According to performance points: high gain antenna, medium gain antenna... According to the point: omnidirectional antenna, directional antenna, sector antenna... According to the purpose: base station antenna, TV antenna, radar antenna, radio antenna... According to the structure: line antenna, plane antenna... According to system type: unit antenna, antenna array... ......
Mobile communication base station is mainly a plate-shaped directional antenna.
Omnidirectional antenna
Everyone pays attention to this stuff in the red box below.
We often see it on the tower, but it is not the antenna of the base station! It is a microwave antenna.
Parabolic antenna. Dish antenna.
Sometimes, this base station is relatively remote. The signal will be sent to the telecommunications equipment elsewhere by microwave. Emergency communication vehicles also generally have microwaves (because it has no fixed line).
(Look at the top of the antenna)
In addition to the microwave antenna, there are many other antennas for other purposes.
â–¼ Eighty antenna â–¼
â–¼ Whip antenna â–¼
Connecting the antenna to the RRU — Feeder.
Generally black, relatively thick, and the number of roots is more. The joint is also very large.
In addition, people often see a small white hat on the side of the antenna. This is the GPS mushroom head for positioning and clock synchronization.
Tower
The antenna is mounted on the tower. The tower is also divided into many kinds.
The base station has a large base station and a small base station. Large base station is called macro base station (macro station). Small base station, in addition to macro base stations and micro base stations, to solve the signal coverage problem at a lower cost, there is also a common device — repeater.
Repeater
The following is a repeater. Looks like RRU.
There is such a
The repeater is actually a signal repeater (Repeater). Amplify the uplink and downlink RF signals. Used to solve the coverage problem of the weak zone of the signal blind spot.
Repeaters are mainly cheap, and the cost is much lower than that of a base station.
Indoor distribution system
Indoor signal coverage has always been a big problem. Base stations are generally built on the top of the building and the like. Once the person entered the building, mobile phone is easy to have no signal. Especially the basement and parking lot. There is an elevator (Standard iron box, the shielding effect is proper).
and so
For indoor environment, an indoor distribution system will be specially set up. It is also the “room division†often said in the industry. “Room†is actually the secondary relay and enhanced coverage of the signal. Receiving feeders from sources such as microcell base stations or repeaters, then to each room or passage, reuse the antenna to send a signal.
It’s similar to the WiFi that everyone often uses.
Everyone who often sees this on the top of the office, dongdong like a pacifier, is the ceiling of the “roomâ€.
â–¼ There are many types of models â–¼
Miniaturized base station
Nowadays, base stations are developing towards miniaturization. On the one hand because it does not take up space (provincial rent = save money). On the other hand, it is also energy-saving and environmentally friendly (power saving = saving money). The final deployment is more convenient and convenient (saving labor = saving money).
If it is miniaturized, is the BBU and RRU fit? Or RRU and Tianshen fit? Simply, BBU, RRU, and Tianqi together.
â–¼ Nokia's "Backpack Base Station" â–¼
I used to hit the back radio station and later hit the back "base station." Hey~
All in all, how small can be, how small and this
Is it very similar to a home WiFi router? It is called Femto. English means "one-billionth of a billion, femto." It is a low-power small-range coverage home base station.
Base station identification
Ok! The introduction is introduced! As the saying goes, "the insider looks at the doorway, and the layman looks at the excitement." For a variety of base stations, it is difficult for ordinary people to distinguish which carrier they belong to. But real "senior" communication Wang can be judged by some details.
Long long ago, each operator had its own base station. The style and characteristics of each base station were still relatively easy to distinguish. E.g., China Mobile generally GSM900 and DSC1800 two G network bands. So if you see the base station tower, there are two layers. Or only one layer (there are only a few people, only G900, no D1800). Then this base station is likely to be China Mobile. In addition, the DSC1800's antenna is twice as short as the GSM900 antenna. Do you know why?
China Unicom has added another CDMA network. So there will be another layer. If you see a base station with a three-layer antenna, it is very likely that it is the base station of China Unicom. In addition, China Mobile compares local tyrants. The base stations are all beautifully decorated and will be tiled. And the base station house is broken. Generally it is Unicom. You ask me the base station of the telecommunications? Hold the grass. China Telecom did not have a mobile business before. Telecom used to have PHS. It is "half mobile business" (Do you still remember?).
PHS antenna is very good. That's it.
No need to count, a total of eight. Eight channels corresponding to PHS. But now PHS has retired. Some of these base stations are transformed into LTE base stations by telecommunications because if the major operators build their own base stations, it is easy to cause high cost and waste of resources. So China established the "China Tower," specialized in infrastructure construction for base station sites. The three major operators leased the site to it. Avoid duplicate construction and malicious competition. Save a lot of money and things. Base station co-location (that is, many base stations are piled together) is more common now.
Base station co-location (that is, many base stations are piled together) is more common now.
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