What are the advantages and disadvantages of 2.4G Wi-Fi and 5G Wi-Fi?

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What are the advantages and disadvantages of 2.4G Wi-Fi and 5G Wi-Fi? [Copy link]

At present, mobile phone and router manufacturers often use concepts such as "dual-band" in their promotions. When we connect to WiFi networks, we often see the words 2.4G and 5G. At the same time, whether 5G WiFi is supported has become an important reference for people to choose a certain mobile phone in many cases. Perhaps in many people's cognition, the 5GHz band can crush the 2.4GHz band in all aspects, but the actual situation may not be the case.
　　So let's talk about the 2.4GHz band and the 5GHz band of the router, and discuss their respective advantages and disadvantages, and in which environment they are suitable for use.
　　According to the provisions of IEEE 802.11 and its improved standards, the carrier frequency used by the wireless local area network is divided into two parts, the 2.4GHz band and the 5GHz band, and each part is divided into several channels at a certain frequency interval. These channels are called WLAN channels, and the frequency corresponding to each channel is actually the center frequency of the channel. As for the use and allocation of channels, each country formulates its own policies. Compared with the 2.4GHz band, the 5GHz band has a larger bandwidth, lower latency, and a more stable network. So why don't we just remove the 2.4GHz band? Actually, it is not entirely true, otherwise there would not be so many dual-band routers on the market.
　　The 2.4GHz band can be divided into 14 WLAN channels. Except for the 12MHz interval between the 14th channel and the 13th channel, the interval between the remaining channels is 5MHz. The IEEE 802.11 standard stipulates that each signal needs to occupy 20MHz (actually 22MHz) of bandwidth, which is equivalent to 5 WLAN channels. Therefore, when a wireless router occupies a channel in the 2.4GHz band, a total of 5 WLAN channels centered on this channel will be included in the range used by the router. For example, when the router occupies the 4th channel in the 2.4GHz band, it has actually occupied a total of 5 channels from 2 to 6. Therefore, the channels actually occupied in the 2.4GHz band are more than the channels that need to be used, so the 2.4GHz band is easier to be filled.

　　The range of the 5GHz band
　　is undoubtedly much wider than that of the 2.4GHz band, and the coverage range is actually from 4.9GHz to 5.8GHz. The division of channels is also more diverse, but there is one standard that remains unchanged, that is, when the center frequency of the channel increases by 5MHz, the channel number increases by 1, which is basically consistent with the standard of channel division in the 2.4GHz band. Currently, most wireless routers that support the 5GHz band use the low 36th channel to the 165th channel, corresponding to the frequency of 5.17GHz to 5.825GHz. In terms of the number of channels alone, even if the compatibility of regions and devices is taken into consideration, the actual number of channels that can be used in 5GHz is much more than that in 2.4GHz.

　　5GHz band
　　However, the wall penetration ability of 5GHz is weaker than that of 2.4Ghz. Generally speaking, it is determined by the physical characteristics of electromagnetic waves. The longer the wavelength, the smaller the attenuation, and it is also conducive to bypassing obstacles and continuing to propagate. The 5G band can carry more data due to its higher frequency, but the wavelength is short, so the attenuation of 5GHz is greater when it passes through obstacles. Of course, there is nothing wrong with your understanding, but we have a more scientific explanation. The
　　main propagation mode of electromagnetic waves in the 2.4GHz and 5GHz bands is linear propagation. When encountering obstacles, they will produce various phenomena such as penetration, reflection, and diffraction. Among them, penetration is the main phenomenon, and only a small part of the signal will be reflected and diffracted. However, electromagnetic wave signals will lose a lot of energy when penetrating obstacles. Sometimes the energy has been exhausted before penetrating the obstacles. As a result, the receiving end receives the signal through reflection and diffraction. In short, the signal bypasses the obstacle.
　　The electromagnetic waves in the 5GHz band have stronger penetration than those in the 2.4GHz band, but the reflection and diffraction capabilities are not as good as the latter. When electromagnetic waves of the two frequency bands encounter obstacles, almost all the energy of the 5GHz signal will be used for penetration, while part of the 2.4GHz signal will be reflected and diffracted, bypassing the obstacle and continuing to propagate. Therefore, although the 5GHz signal chooses the shortest transmission path, there will be a lot of energy loss during the transmission process. The 2.4GHz signal will take a longer path, but it retains more energy, which in our opinion means that the signal strength is stronger.
　　In short, if the router and the device are separated by a thick wall, the signal of the 5GHz band may be very weak, and the 2.4GHz band can be used normally. If there are two walls between them, the 2.4GHz band may be barely usable, but the 5GHz signal may not be found.

　　Image: Xiaomi Mall Router Introduction Page
　　When both 2.4GHz and 5GHz bands can be used normally, the 5GHz band will perform better. As mentioned earlier, the 5GHz band has a higher frequency, so it can carry more information, and because the network environment is better, it can provide a wider bandwidth and more stable network. The 2.4GHz band has a lower frequency, and there are many devices using the 2.4GHz band. Many dual-band routers also use the 2.4GHz band and the 5GHz band at the same time. So if there are many people using the 2.4GHz band, the network stability will be poor. In addition, the 2.4GHz has better wall penetration performance, so there will be more network interference in apartments and other usage scenarios. To put it simply, it is better to use the 5GHz band when downloading, streaming, voice and online games.

　　Image: TP-Link official website
　　To summarize the above, the 5GHz band has a better wireless environment, stable network speed, and can support higher rates; the 2.4GHz band has a poorer wireless environment. If there are too many devices around, the network speed may not be stable, but it can cover a longer distance.
　　In terms of specific usage scenarios, if you do not have high network requirements for mobile phones and computers, the 2.4GHz band is completely sufficient, and it is also sufficient for IoT devices such as refrigerators and table lamps; but if you need to play 4K videos, or the call quality of Internet calls and prefer to play online games, it is recommended to use the 5GHz band.
　　If your router is placed in the bedroom and there is no need for wall penetration, the 5GHz band will be better, and if the indoor area is large and more rooms need to be covered, the 2.4GHz band is more practical. But if you need to meet both coverage area and network quality requirements, you need to consider a multi-route solution.

　　Image: Xiaomi Mall router introduction page
　　However, dual-band routers currently support both 5GHz and 2.4GHz bands, so you don’t have to worry too much when buying a router. In addition, based on the current actual situation, the network itself will have a greater impact on the user experience.