Recently, OpenSignal, a foreign research institute, compared the download speed of Wi-Fi and mobile network around the world, found that the average download speed of mobile network in 33 countries, such as Australia, Germany, Greece, Myanmar, exceeded the download speed of local Wi-Fi. Based on this, some people even give the judgment of "Wi-Fi is dying".
So where is Wi-Fi going in an era when mobile speeds are constantly refreshing records?
"Wi-Fi is dying" is not alarmist
Wi-Fi is essentially an alternative to wireless Internet access. In the case of high mobile network fees and difficult access, Wi-Fi converts cable signal into wireless signal, which improves access convenience and reduces access cost, thus providing an ideal wireless access scheme for users.
"These advantages of Wi-Fi will be weakened with the landing of 5G applications and the reduction of corresponding fees. To some extent, the judgment that'Wi-Fi is going to die'is not alarmist." Zhao Zhenying, a researcher at the National Engineering Laboratory of Electronic Commerce Transaction Technology and an Internet of Things observer, said.
In an interview with a reporter from Science and Technology Daily, Xiang Ligang, CEO of the communications portal Feixiang Network, said whether Wi-Fi would be replaced should be seen in different application scenarios. "Public Wi-Fi may be replaced, but household Wi-Fi is not likely to be replaced at present." Xiang Ligang said.
Because the public Wi-Fi network is slow and unstable. "In public places, dozens of people usually connect to the same router, because too many connecting devices will inevitably lead to slower network speed. In addition, wireless network has limited coverage and does not support continuous use. Its signal strength will decrease with the increase of distance between devices and nodes. For example, Wi-Fi technology itself has 11 MB/s transmission speed, but as distance increases, the network speed of user terminals is only 1 MB/s. At the same time, wireless signals are vulnerable to interference from buildings.
At airports or stations, users generally do not stay at the same place for a long time, and they are likely to move frequently. If the mobile distance is too long, the device in the user's hand is likely to be disconnected from one router and reconnected to another. "If in the mobile network environment, users do not have to switch between different routers, at any time connected to the network." According to Xiang Ligang, the number of users in public places is huge, and the speed of Wi-Fi accessing the Internet rarely exceeds 10 MB/s, but the theoretical speed of 4G can be as high as 300 MB/s, and at least 20 MB/s-30 MB/s is guaranteed. With the coming of 5G era, Wi-Fi in public places is likely to be replaced.
"But at the moment, I see no sign of Wi-Fi being replaced at home or at work." Xiang Ligang said that the mobile range of users in the home and office is relatively fixed, and people who use the same router are not as many as in other occasions, at this time the speed of using Wi-Fi to access the Internet is more guaranteed. From a realistic point of view, the possibility of connecting home computers, televisions and tablets to mobile networks is unlikely.
Zhao Zhenying believes that this is not the competition between Wi-Fi and mobile networks, but the competition between wired and wireless networks. "Wi-Fi is nothing more than signal conversion. When the mobile network is fast enough, there is no need to convert wired network signals into wireless signals. So Wi-Fi has no value in existence. Zhao Zhenying said that this is like when the mobile phone has the function of short message, the BP machine has no value and quickly disappears.
Mobile network has more advantages in spectrum resources
What determines the speed of the network? First of all, we need to mention the concept of "spectrum". Spectrum resource is the lifeblood of mobile communication, and the spectrum range basically determines the characteristics of a wireless technology.
"Spectrum is to communication as land is to real estate. Without land, we can't build a house. Without spectrum, we can't achieve communication transmission. According to Xiang Ligang, spectrum resource is the carrier of wireless communication to transmit information and the essential basic resource of mobile communication system.
Xiang Ligang said that there are good and bad land, as well as good and bad spectrum. The spectrum penetration in low frequency band is stronger and the transmission distance is farther. But spectrum resources are limited, and good land is often acquired first-come. Unlike the vast majority of countries, China uses the way of distribution rather than auction to supply spectrum. High-quality spectrum resources have been allocated to the army, scientific research institutes and radio and television stations as early as possible.
"In the past, mobile communication resources mainly served the telephone business, not the Internet business. Telephone calls do not require a lot of spectrum, so mobile communications can get very little spectrum." According to Xiang Ligang, this leads to poor spectrum resources in mobile communication networks.
If good land is divided in advance, we must find ways to maximize the use of existing land. "With the technological updating, the utilization rate of mobile communication spectrum resources has been continuously improved, and the network deployment capability has been gradually enhanced." Xiang Ligang said.
Cellular technology of mobile communication is a way to improve land use efficiency. Cellular mobile communication system is composed of mobile service switching center, base station equipment, mobile station (user equipment) and transmission line from switching center to base station. According to Xiang Ligang, cellular technology has such advantages as better service performance, higher spectrum utilization, compact user terminals and low radiation. "When using mobile network to communicate, the mobile device connects to the next base station and then cuts off the connection with the previous base station. This soft handoff ensures that users can use the network smoothly." But Wi-Fi technology does not have such a mechanism.
Wi-Fi technology, which started in 1999, has used two bands since its inception, one is 2.4 GHz and the other is 5 GHz, of which 2.4 GHz is the main push. However, the bandwidth of the 2.4 GHz band is less than 100 MHz, which limits its transmission rate. Another band of 5GHz is idle due to poor diffraction and penetration capabilities and high deployment costs.
Later generations should work on safety
The essence of Wi-Fi is to convert wired network signals into radio networks. Common routers are used to achieve this conversion. The mobile network directly connects to the base station, and the base station connects to the wired network. From a technical point of view, mobile network has more advantages in security than Wi-Fi.
Zhao Zhenying said that 5G transmission rate could theoretically reach 10GB/s. At present, the three major domestic operators have announced the timetable for the construction of 5G network, and it is not a problem to achieve commercial use by 2019. "In theory, mobile network speed has basically surpassed Wi-Fi, and practical application will begin to land in 2019." Zhao Zhenying said.
"The development of mobile network has experienced an evolutionary process from analog to digital, from 2G, 3G to 4G and 5G. In this process, Wi-Fi is only an alternative solution to solve the mobile network relative to the fixed network is not mobile, slow access speed and high fees. Zhao Zhenying emphasized that if these three problems of mobile network can be solved, the corresponding alternatives will accomplish their mission. So it is not the mobile network that replaces Wi-Fi, but the mobile network that solves its own problems and makes the "patch" of Wi-Fi worthless.
Zhao Zhenying believes that after 5G is fully commercialized, users'demand for high-quality network speed can be basically met. "If there is any new technology, I think it should be moving towards a safer direction, such as quantum transmission." Zhao Zhenying said.
With the acceleration of mobile network iteration, the traditional access technology is also breeding a "revolution" and trying to widen the spectrum resources. Previously, some researchers proposed to use green energy-saving LED lights as the communication mode of transmission base station, which is called Visible Light Communication (VLC).
Visible light communication refers to the use of fluorescent lamp or light emitting diode emitted by high-speed light and dark signal to transmit information. Compared with radio communication, visible light communication has opened up new spectrum resources. Its transmission rate, security and privacy are very high. It has no electromagnetic interference and radiation, and does not need Band permission authorization. It can realize high-speed wireless communication at low cost with the help of LED lights. "When the light is turned on, it's Wi-Fi, but the light doesn't have the ability to diffract and penetrate. This means that you can surf the Internet in front of the light bulb and drop the line as soon as you turn around. Maybe in the future, he said, reflections and other technologies could be used to improve it.
"Generally speaking, Wi-Fi has the characteristics of flexible networking, and there is no real alternative to Wi-Fi in specific areas, especially in indoor local environment, so Wi-Fi will survive in the short term." Xiang Ligang said, but it is undeniable that Wi-Fi technology is being marginalized because of its security risks, large power consumption, small coverage area and poor network stability.
Source: Science and Technology Daily