As we all know, although the communication industry is collectively referred to as “communication” externally, in fact, it is divided into three subdivisions internally, namely wireless , transmission , and core network .

Between the three plates, the technical differences are huge, which is equivalent to interlacing. Most communicators are usually only good at one of them.

If someone can understand both at the same time, it is a rare talent. Knowing three at the same time is rare.

Mr. Xiaozao is a core network professional. I used to only understand core networks, not wireless, nor transmission. Later, because of work needs, I started from scratch and gradually mastered some fur.

As I continue to learn more, I often compare wireless, transmission and core network, trying to find the answer to the previous question, that is to say: “core network, wireless and transmission, which one is the most difficult? Where is the difficulty?”

To put it bluntly, this problem is also a problem of the chain of contempt in the communication industry .

When working on a project, the project team includes wireless engineers, transmission engineers, and core network engineers. Everyone quarreled a lot—

“I have no problem here, it’s all your problem!”
“You have the problem, your whole family has the problem!”
“Can you do it? You can’t solve such a simple problem!”
“Your wireless is a lot of shit! ”
“Have a problem? Find the transmission!”
“Your core network is too perverted, and our wireless is not so complicated!”
…
Arguing and arguing will always return to the core of the problem: “My technology is the most difficult in this field. Understood, don’t blind BB.”

So, among the three major fields, who is the most difficult? Let me put aside the background of the core network and make a fair and just comment.

let’s look at it separately

first look at wireless

Although the wireless thing is called wireless, it essentially includes multiple processes of encoding, modulation, and radio frequency. Each process is independently a specialty, and the content is extremely complicated.

The basic process of the physical layer of 5G NR

From the perspective of the air interface only, wireless channels, signals, physical layer frame structures, scheduling algorithms, and signal measurement switching are key and difficult points. There are too many contents that need to be memorized forcibly, and a lot of basic theoretical knowledge of mathematics is involved, which requires a high IQ. Most people just give up before getting started.

Especially after the arrival of 5G, wireless technology has become even more perverted. High-order modulation, Massive MIMO, and beam management are all brain-burning knowledge points that seriously threaten the hairline.

The coexistence of 2/3/4/5G on the existing network has also increased the difficulty of learning and working for wireless engineers, and the situation that needs to be dealt with is very complicated.

I personally think that from the perspective of technical principles, wireless is much more difficult than transmission and core networks.

It should be noted that although the technical principle of wireless is difficult, the division of labor is meticulous.

From the perspective of R&D, each wireless R&D engineer only studies his own subdivision field, and those who learn algorithms work on algorithms, and those who learn radio frequency work on radio frequency, which reduces the ability requirements to some extent (but it is still difficult).

Moreover, from the perspective of engineering execution and equipment activation and maintenance, the difficulty of wireless is further reduced.

Because product activation does not involve too many underlying technologies. Products and solutions have already formed standards, and they have been determined to death. You can just follow them. You don’t need to know why you do this, which reduces the ability requirements for engineers.

The difficulty of field wireless engineers lies in the workload. In other words, it is tiring and hard work.

There are many wireless sites, and there are many places to run. As a wireless engineer, if something goes wrong, I often have to get off the station, or even drive hundreds of kilometers, which is much harder than the core network.

There is also a theology of wireless, which is network planning and optimization, which is commonly known as “network planning and network optimization”.

When I was engaged in the core network before, I never understood that our core network business trips are always done by one person. Why does wireless always have “one wireless + one network optimization” every time? Isn’t it over if one person handles it?

It was only later that I realized that network planning and network optimization is really a metaphysics, and I can’t do it part-time. For things like wireless network coverage optimization, doing or not doing it, doing it blindly and doing it seriously are completely different things.

It looks like adjusting the antenna and changing the parameters, but the effect is very different.

Next, let’s talk about the core network

Mr. Xiaozao has worked on the core network for more than 10 years, and he really loves and hates this thing.

Back then, the core network was recognized as the most difficult of all the company’s products.

This difficulty does not refer to technical principles, but project delivery.

Among the product lines of the company, the core network product line has the most product categories – CS circuit domain, PS packet domain, IMS domain, etc., with dozens of product subcategories and hundreds of product models, which is dazzling.

Feel free to send a product category list, let everyone feel:

The above table does not include 5G, nor is it specific to product models (about a few hundred).

As a core network engineer, you must not only understand the overall architecture of the core network, but also understand the hardware and software knowledge of countless core network devices, and know how to debug, install and connect tests.

The core network has many network elements and devices, so the network architecture is particularly complex. There are many interfaces and protocols between network elements, and the process of implementing services is extremely complicated.

This picture is just a 4G LTE…

In these processes, there are many possible problems, and the investigation process is particularly perverted. At this point, wireless engineers are beyond the reach.

There are many product models of the core network, which will also bring about a problem, that is, there are too many documents, and the learning process is very painful. Especially for newcomers, they are very unfriendly, straightforward and suspicious of life.

There is another abnormal point about the core network, that is, it is very risky.

Once the core network goes down, it will be a major failure, affecting hundreds of thousands, millions or even tens of millions of users. This pressure is unbearable for most people, and it requires extremely high psychological quality.

In terms of working conditions, core network engineers are better than wireless engineers. The core network computer room is generally located in the city, and there is no need to frequently go to remote areas or move around.

I almost forgot to mention that although there are many core network products, they do not take volume, do not make money, and sometimes they are even given away for nothing. Therefore, core network engineers have a high spiritual status and a low material status.

In contrast, wireless is a big money maker. Huawei has a saying that “sacred wireless, god terminal”, which means that wireless is especially profitable. In ZTE, wireless is also the most profitable product line.

The development path of core network engineers is also relatively narrow.

Wireless engineers can work in equipment vendors and operators, as well as mobile phone manufacturers, wearable device manufacturers, and router manufacturers. Core network engineers can’t do it. There is no other place to go except for equipment vendors and operators. Resignation can only change careers.

Finally, let’s look at the transmission

Compared with wireless and core networks, the technical difficulty of transmission is not particularly high, and it is also a bit “small and transparent”.

To put it bluntly, the transmission is divided into two parts, one is the bottom layer (physical layer), and the other is the upper layer (above the physical layer). To be simpler, the former studies how to run fast, and the latter studies where to run.

The bottom layer (physical layer) of transmission only studies one thing, and that is light.

For this thing alone, the difficulty lies in the optical module. Inside the optical module, the laser emits light and the detector receives light. Its difficulty lies in the optical chip. There are not many companies engaged in optical chips, and most people will not have the opportunity to study them.

In addition to the optical module, the interior of the optical communication equipment is to study how to converge and disperse the optical paths, such as optical crossover, ROADM, OXC and the like.

These things, the difficulty lies in the WSS wavelength selective switch. To put it simply, it is to study how to separate the light of different wavelengths in a beam of light and send them to different directions.

Ultimately, WSS is a technical problem, not a communication problem. Therefore, there will not be too many communication people who study, and the research is done by people majoring in optics.

In addition to optical modules and optical devices, optical fibers and optical cables are glass. This stuff is purely based on volume in the market, no different from selling cabbage, and the profit is meager, so it is not worth doing.

Going from the bottom to the top, there are things like FlexE and FlexO. To put it bluntly, it is to study the technology of channel binding and unbinding, small roads into big roads, and big roads into small roads.

Further up, MPLS, SR and the like are not particularly difficult in terms of technical principles.

The upper layer of transmission, to put it bluntly, is routing and switching, and data communication technology.

This stuff is the structure of data packets and advanced routing protocols. Their basic principles are definitely not difficult to talk about. There are only a few routing protocols. If you have a thorough understanding, it’s over. Now the HCIE and CCIE all over the street are basically digital. (In contrast, the core network is a proprietary protocol and a proprietary interface, which is more difficult. Although 5G is now easier, 2/3/4G is still there, and the pain is still there.)

The external working conditions of the transmission engineer are rather harsh.

First, their working environment, sometimes as bad as wireless.

Secondly, their work risks are comparable to those of the core network.

Third, because transmission is the connection between communication devices, and has a close intersection with wireless and core networks, it is easy to be caught in the middle. When there is nothing to do, it is “little transparent”, and when there is something to do, it is released to take the blame.

The employment of transmission engineers is slightly better. In addition to operators and equipment manufacturers, many enterprise private networks and data centers now need transmission talents, and there are more choices.

Well, the above is the comparison of wireless, transmission and core network.

In summary, from the perspective of technical principles, wireless is the most difficult. From the perspective of project work, the core network is the most difficult.