In the era when smartphones were just popularized, Wi-Fi was a popular search term on major shopping platforms.
That's because 4G traffic is expensive in the early days, consumers with smartphones have begun to use mobile phones to chat, shop, and watch videos, Wi-Fi has become a good choice in the family, but the Wi-Fi router will have a poor signal across one or two walls, and a large number of consumers need routers with better signals.
In the 5G era, traffic is cheaper, but Wi-Fi still has irreplaceable value, and with the increase in the frequency of watching live broadcasts and online videos, the requirements for Wi-Fi are higher.
Consumers still need a router with excellent signal coverage.
However, you will hear a statement that the signal of the router is limited by national regulations on the power of the router.
This is actually a misleading statement, and it is not impossible for a single router to achieve full coverage of 200 square meters.
A small team of dozens of people led by two engineers took 5 years to bring about disruptive changes.
"You're very laymen." This is the evaluation received by Wang Ziming, founder and CEO of Deyi Communications, and Petri Manninen, co-founder and CTO of Deyi Communications, two experts in Nokia's base station chip department when they started their businesses in 2019.
What may be the next moment for the "layman" to bring a 10-fold increase in RF performance and revolutionize the industry.
Poor Wi-Fi signal coverage is not due to power limitations
At a time when consumers are enthusiastic about Wi-Fi routers, there is also a heated discussion about the radiation problems that may be caused by boosting the Wi-Fi signal. Therefore, many people have come to the conclusion that the reason for the poor performance of Wi-Fi routers through walls is the limitation of router power by regulations.
This is a false conclusion.
"In fact, the poor signal of the router is the reason for the slow development of materials." Wang Ziming said, "In 2023, the power standard of mainland routers will be the same as that of the United States and Europe, and the upper limit will no longer be at the milliwatt level but at the watt level, but the output of Wi-Fi6 routers will only be 100 milliwatts at high network speeds." ”
Before explaining that materials are limitations, it is important to understand that whether it is a mobile phone or a router, the main communication is the baseband chip and the RF chip. The baseband chip handles throughput, security, and bearer users, while the RF chip is responsible for the transmission and reception of signals, so the signal coverage is mainly determined by the RF chip.
The key to determining the performance of RF chips is the material, the RF devices of 2G Nokia mobile phones used gallium arsenide materials decades ago, and the RF devices in 5G mobile phones today also use gallium arsenide.
Because there has been no breakthrough in RF device materials for so many years, even if you add money, you can't buy better RF devices, and today's mobile phones and routers are already products produced from the best materials.
The improvement of a single RF device has been limited over the years, and the superposition of two RF devices cannot achieve the effect of 1+1 equals 2.
"With two 100 milliwatt RF devices, you may get 150 milliwatts of power, and the combination of the two devices will make the signal quality worse, and the more RF devices are added, the power will slowly increase while the signal quality will drop sharply, and the signal coverage problem cannot be solved." Wang Ziming said that it was like connecting more carriages together to get a train.
And by increasing the coverage area of RF devices, the cost increase is exponential, such as more than 2 times the cost increase, which can be exchanged for a 35% performance improvement, because the RF device of gallium arsenide has reached the limit, and more redundant designs are needed to work stably.
The only solution to the signal coverage problem of Wi-Fi router - the "engine" of the macro base station
To solve the problem of router signal coverage, it is necessary to jump out of the limitations of existing RF devices.
RF signals have always pursued more power saving while transmitting with larger bandwidth and higher power. However, the physical characteristics of these three indicators contradict each other, and the contradiction between using higher power transmission and power saving is easy to understand.
For digital chips, Moore's Law enables higher performance and lower power consumption. However, RF chips do not have a similar law to solve the contradiction, and with the popularization of live broadcast and high-definition video, consumers' requirements for network experience are also increasing, especially with the development of generative AI, consumers' requirements for network throughput and real-time performance will further increase.
"The performance of RF devices lags behind user needs by 10 times or more." Wang Ziming said, "This is the problem of RF devices that we have defined. ”
This definition is critical, "The problem we define is that the performance of RF devices is far less than what consumers need, which was not the industry consensus in 2019, and it is not necessarily today. Wang Ziming told Leifeng.com, "We have defined this problem, that is, to provide users with imperceptible connection, which needs to achieve a 10-fold performance improvement, and the only way is to use the macro base station to compensate for it." ”
The macro base station compensation method introduces a digital compensation chip to achieve high-quality network signals with the largest possible power while reducing power consumption.
The specific implementation is to let the RF device be responsible for the output of high power, which will distort the signal, but adding a RF compensator can compensate for the distortion part, and the cooperation between the RF device and the RF compensation chip can make the output of the signal clean, high power and low power consumption.
This has long been a common practice for macro base station providers, RF devices can be purchased, and then self-developed digital front-end chip DFE, 80%-90% of the digital front-end chip is a predistortion chip that compensates for RF.
To apply this idea to products including routers, it is necessary to add a chip, which is difficult to accept in the cost-sensitive RF industry, so some people think that Wang Ziming's entrepreneurship is "very layman".
"Not only to achieve the compensation performance at the macro base station level, but also to achieve the cost of router consumer electronics, which is what we have done in the past five years." Wang Ziming introduced that the RPU of Deyi Communication is not only suitable for the scenario of low-power but high-modulation 1024/4096QAM of Wi-Fi router, but also suitable for the scenario of 100W and 400M bandwidth macro base station.
The RPU of Deyi Communication is an analog RF incoming and outlet, which does not require any digital signal, which is equivalent to a small power amplifier and has strong compatibility.
RPU allows one router to top three, covering the whole house of 200 square meters
Practical testing is the best way to test this method. The test data given by Deyi Communication, in the comparative test done in the laboratory of the head operator, the three curves represent the three routers, the green is the router provided by the operator, the blue is the performance data of the RPU chip added to the operator's router, and the red is one of the most expensive routers that can be bought online.
It can be seen very obviously that with the attenuation of the signal, the router with the RPU chip can increase more than a dozen DB, that is, 10 times the coverage area and transmit power, taking into account power saving.
Ordinary routers output tens of milliwatts of power at the maximum network speed, and at least 500 milliwatts of power at low network speeds, so they can connect but cannot connect to the network. With the addition of the RPU chip and the compensation system, it can be at full speed at 500 milliwatts of power, without the need to switch to the low-speed network.
The compensation algorithm is the core of the RPU.
"Our RPU not only has a digital predistortion algorithm, but also a series of various compensation algorithms, so macro base station customers can also use our chips." Wang Ziming further said, "The difficulty of pure algorithm chips is to use good performance and compensation capabilities to make Wi-Fi high-power output, and higher performance and consumer-grade low cost are a contradiction. ”
It is a system to solve the problem of good and contradictory cheapness, especially the RPU is a digital-analog RF hybrid chip, which is equipped with a large number of complex algorithms, and the difficulties must be broken one by one, and there is a lot of trivial and cost-reducing work in the middle.
"Many professional chip companies pay attention to hitting the right shot, but we have repeated trial and error in order to have today's comprehensive cost reduction." Wang Ziming said.
The RPU also uses an advanced AI architecture, unlike large models that do not require expert knowledge, Digyi Communication fully uses expert knowledge to build a set of AI closed-loop control under the goal of pursuing extreme performance and cost.
All outputs of the RF device are collected back into the training processor to update the physical inverse model, so it can cope with real-time changes in RF signals due to temperature, environment, and interference, and the speed is in the microsecond range.
"The predistortion processing capability of the base station makes the signal extremely clean and free of interference, and we have RPU chips with the same function to make the signal of the router and base station better than the indicators required by 3GPP, greatly reducing the signal interference between the drone and the router." Wang Ziming also said, "The power consumption of the RPU is also very low. ”
Compared with the 10% efficiency of traditional RF devices at full speed, the efficiency of RPU will have 20%-40% efficiency in different frequency bands, achieving the effect of low power consumption.
The RF revolution is coming
At the same time, it can achieve larger bandwidth, larger power transmission, and low-power RPU, which is currently being poured into the head customer and is expected to be put into production by the end of this year.
In the future, the RPU of Deyi Communication will evolve in the direction of being smaller and more cost-effective. This includes the direct integration of peripheral supporting chips, such as power supplies, into the RPU.
On the router side, Deyi Communication will also carry out reception enhancement compensation, so that even if there is no RPU chip in the mobile phone, the router can "hear farther" to further improve the experience.
Now that the core challenges and solutions of router signal coverage are clear, it can be found that Deyi Communication uses the idea of macro base stations to small base stations, drones, routers, etc.
This is the great value of Deyi communication, macro base station providers can develop digital compensation chips, but to make it miniaturized and lightweight, it is a technical and engineering problem, and it is also a system problem, from this dimension, Deyi communication is a pioneer.
The engineers of Deyi Communications have the vision of digital RF, and they are also using RF to change the lives of ordinary people.
After the leading router companies, operators, and drone manufacturers have all accepted this RPU, which seems "a little weird" at first, the change will soon come.