The military-industrial scientific research system of the academic master.

After hearing this, Wu Wei's eyes revealed a clear look of confusion.

However, after today's round of ups and downs, his mentality has now been tempered to be as solid as a rock.

Therefore, even though he didn't understand at all, he didn't show it and just waited for Chang Haonan's further explanation.

After all, the latter has just mentioned that it involves changes at the hardware level, so in the end it still has to be implemented by their 54th Institute.

Sure enough, after a brief thought, Chang Haonan spoke again:

"In theory, as long as the mapping relationship between the superimposed waveform and the information can be established, the superimposed waveform can be demodulated directly without demodulating each user's information separately... Only one XOR operation is required to eliminate the self-interference caused by the broadcast effect, and it will not add too much additional computing power and power consumption to the system."

"In addition, a typical single-hop two-way relay communication will only have two time slots in the middle, instead of three in the traditional transmission strategy, which is equivalent to increasing the theoretical throughput by about one third..."

The leap in this deduction was indeed quite large, but it made Wu Wei's eyes clearer.

Looking at the other party's expression, Chang Haonan knew that he probably didn't explain the two paragraphs he had just said, so he had to return to car number one and take out the notebook.

While waiting for the results of those rounds of experiments, he had already written down some ideas.

"Under the half-duplex condition, the system needs to perform two stages, uplink and downlink, to complete a two-way relay communication. In the uplink stage, node 1 and node 2 simultaneously send their own data frames S1 and S2 to node R. In the downlink stage, node R demodulates and performs network coding mapping based on the received superimposed electromagnetic wave signal to form a network coding data frame SR and broadcast it to nodes 1 and 2."

As Chang Haonan spoke, he found a page with relevant content in his notebook and handed it to Wu Wei:

"Because there is a mapping relationship between the superimposed waveform and the information, the node can recover another data frame by using the coded data frame SR and a data frame it already has. At this point, the entire two-way communication process has been completed, and there is no need for a third time slot."

"Of course, the key point of this process lies in the specific scheme of the relay node R for processing the received superimposed electromagnetic wave signal. I haven't thought about how to design this yet..."

While listening to Chang Haonan's explanation, Wu Wei quickly scanned the contents of the notebook.

Although the illustrations were a bit abstract and the handwriting was rather flamboyant, he was not a beginner with zero basic knowledge. Besides, there was the note-taker teaching on the spot, so he quickly understood the content.

after that……

He couldn't help but watch it again.

Although the above does not involve engineering implementation methods, even if we only look at it from the perspective of ideas, it is enough to make people applaud.

It’s a pity that the two of them were standing in a Gobi desert and had no table to use.

So Wu Wei had to settle for the next best thing and slapped the hood next to him:

"Mr. Chang, isn't this just another implementation of network coding at the physical level?"

This summary is indeed insightful, and can even be said to penetrate the essence through the phenomenon.

Even Chang Haonan couldn't help but look at him differently.

"That's really the case from a principle perspective..."

He nodded:

"In my opinion, this technology should be called physical layer network coding technology..."

"..."

……

Just as Chang Haonan was busy developing a two-way communication relay system.

Another key project of the Aviation Power Group has also achieved important interim results.

After about two years of research and development, the first SeA650 prototype in complete technical status was finally assembled and rolled off the production line at the Snecma Group's factory in Villaroche.

Moreover, a few days earlier, Snecma's wholly-owned subsidiary, the Herrero-Dubois Group, had already produced two sets of engine nacelles for the first prototype according to the design provided by the Chinese side.

This means that the power system of the entire Falcon Z project has officially entered the actual machine testing stage.

Of course, since the entire SeA series of engines uses the M88-3 core engine, which has previously undergone a total of thousands of hours of single-item experiments in China and France, the entire process will not be as long as a brand new engine.

If everything goes well, the model will surely be able to catch up with its maiden flight early next year.

There will definitely be risks when a new aircraft is equipped with a new engine.

Especially when both sides use a lot of new technologies.

However, thanks to their good aviation technology and excellent basic industrial level, Europeans do not have too much psychological burden about this kind of thing.

Besides, there are no other alternatives available on the market at this moment.

Only the BR700 series, developed jointly by Rolls-Royce and BMW, is in the same league.

However, Dassault Business Jets has never used Rolls-Royce products in the past, and the Falcon Z has integrated flight and propulsion control. If the engine control system needs to be replaced, it may even have to modify a special version of the flight control.

In short, no matter from the market or technical level, it is better to go directly to SeA650.

Anyway, judging from the situation of M88, there shouldn't be any major mistakes.

As the main designer of SeA650, Aviation Power Corporation of China naturally sent a team, led by Liu Yongquan, to France to participate in the delivery ceremony.

When important partners come to visit, the reception style is similar whether they are Chinese or foreign, unless there are special needs such as confidentiality.

First, there is a round of eating and drinking, and then an introduction to the company's development history (if the company history is too short, it will be skipped, or replaced with the boss's history of making a fortune), then a tour of different areas of the factory or R&D center will be arranged according to the specifications, and finally there is another round of eating and drinking.

The formal ceremony will be held the next day.

This is basically the process that Liu Yongquan and others faced.

It must be said that as a veteran aviation company, Snecma's final assembly plant is indeed worth a visit.

Although China has approached or even achieved the international leading level in many individual technologies thanks to its rapid progress in recent years, there is still much room for improvement in the overall organization and management of factories and basic skills such as mechanical processing and manufacturing.

Apart from anything else, just in terms of the workshop working environment and worker safety protection, Liu Yongquan has found many details worth learning from the Liming Factory during his walk around.

Of course, he came here to visit today, not to study.

Therefore, the group went around in circles and soon arrived at the engine that would not be officially delivered until tomorrow but had actually undergone several rounds of test runs on the test bench.

As a small engine with a medium bypass ratio, SeA650 is not large in size.

It is even shorter than the M88 because the afterburner has been removed.

So much so that if thirty or so people wanted to watch, they had to split into two layers, inner and outer.

However, with Liu Yongquan's identity, he could of course have direct and close contact with him.

He leaned down slightly, put his head in front of the tail nozzle, and looked at the turbine structure inside.

It is not difficult to see from the light coming from behind that the turbine blades used on this prototype are still those produced and exported by the Liming Factory.

As for the turbine disc...

Although the view is blocked, the results are obvious.

Since March this year, Snecma has been trying to mass-produce turbine components for the SeA650 at its parts manufacturing plant in Gennevilliers.

But the trial production workshop in Paris is a pilot environment, which is quite different from the actual factory.

In the end, after more than two months, we still failed to produce a complete batch of qualified products.

In desperation, they had to place a new order with China before final assembly, for the production of a total of four prototypes.

To this day, Snecma has not publicly acknowledged that it will use components provided by the Liming factory in its mass-produced products.

But everyone already knows it tacitly——

The yield rate after two months is 0, which shows that there are big problems in the process technology and even the process route, which cannot be solved by simply adjusting the parameters.

Whether it is completely upgrading the existing process or developing a new process from scratch, the cycle is basically calculated in years.

According to the plan, your Falcon Z will make its maiden flight early next year and will be delivered the year after next at the latest.

Where do you get so much time to slowly study new technology?

We can only use imported parts for now and make long-term plans later.

Just like when China introduced the Arriel 1C engine from France.

It’s just that the offense and defense have changed now.

But then again.

With this approach, the next move is almost obvious.

As an important partner, AVIC Aero Engine Corporation of China cannot just wait for Snecma to complete its technical research and development and then kick itself out of the supplier list.

Therefore, it is necessary to sign a contract that guarantees a minimum supply quantity and a minimum delivery time.

That is to say, regardless of whether Snecma has solved the process problem or not, you need to order no less than a certain quantity of products every year for at least x years.

Or simply put, within the entire life cycle of the entire series of engines, no less than xx% of the turbine components must be supplied by China.

In fact, in addition to attending the delivery ceremony, another important task for Liu Yongquan to lead the team here was to communicate with Snecma and reach such an agreement.