Why We Need Wi-Fi 6 in 5G Era?

From 1999 to 2000, some people proposed that 2G would replace Wi-Fi, from 2008 to 2009, they estimated that 4G would replace Wi-Fi. Now, someone is talking about 5G instead of Wi-Fi. However, the application scenarios of 5G and Wi-Fi are different. Wi-Fi is mainly used in indoor environments, while 5G is a wide area network (WAN) technology that is more applicable to outdoor scenarios. Therefore, it is believed that Wi-Fi and 5G will coexist for a long time.

Further analysis can be made from the following aspects:

Traffic：

If 5G technology replaces Wi-Fi, a package with unlimited traffic must be launched. Otherwise, the cost will be far greater than that of broadband. Additionally, the price of broadband is becoming lower, and is a cost-effective choice.

Network coverage：

5G network technology uses ultra-high frequency spectrum (5G frequency band: 24 GHz–52 GHz; 4G frequency band: 1.8 GHz–2.6 GHz, excluding 2.4 GHz). As mentioned above, a higher frequency indicates the weaker diffraction and weaker capability of traversing obstacles. Therefore, 5G signals are easily weakened. If 5G signal coverage is required, more base stations need to be constructed than 4G networks. If there are several walls inside building, the signal attenuation is even more serious. Another extreme example is the basement. The Wi-Fi network can connect a router to the basement to generate signals through wired connections. However, 5G networks cannot cover the basement of all buildings and therefore cannot replace Wi-Fi networks. In addition, almost all smart devices have Wi-Fi modules, and most IoT devices are equipped with Wi-Fi modules. Only one public IP address is configured for the egress device. A large number of IP addresses are used on the LAN. Users can easily manage these devices on their own Wi-Fi networks. On a 5G network, more public IP addresses will be occupied.

Network capacity：

Bandwidth x Spectrum efficiency x Number of STAs = Total capacity. The advantage of 5G is its carrier aggregation technology, which improves the spectrum utilization and greatly increases the network capacity. In the 3G/4G era, when users use mobile phones to access the Internet in densely populated places such as subways and stations, the Internet access delay becomes longer and the network speed becomes slow. In the 5G era, as the network capacity greatly increases, the impact of the preceding phenomena is greatly reduced. It seems that 5G allows for unlimited access. However, with the advent of the IoT era, the number of network access devices greatly increases. If all Internet access devices are directly connected to base stations in the area, this 5G network will certainly be congested. Wi-Fi is a good choice to reduce the burden on the base stations.

Transmission rate：

The three most important features of 5G promoted by mobile device vendors are high speed, large capacity, and low latency. In fact, the latest generation of Wi-Fi is faster than 5G. The latest 802.11ax (Wi-Fi 6) single-stream peak rate is 1.2 Gbit/s (the peak rate of the 5G network is 1 Gbit/s). On average, the time required for evolution of each Wi-Fi generation is about half of that of the mobile network. Therefore, from the latest Wi-Fi 6, the rate will continue to be higher than that of the mobile network.

Terminal type：

All industries, such as office, logistics, business, and smart home, are heading towards all Wi-Fi. The first step is to connect devices, users, and terminals to the Internet. Assuming that 5G replaces Wi-Fi, all connected terminals in the future need to be equipped with a SIM card to access the Internet. This is a reason why 5G cannot replace Wi-Fi in indoor scenarios. Similar devices include VRs, game consoles, e-readers, and STBs.

Battery power consumption of mobile terminals：

Mobile terminals including mobile phones and tablets use batteries for power supply. In most cases, the service life of batteries is considered to be related to the installed services and usage frequency. However, the access quality of various mobile signals is also related to the power consumption of the battery. When the signal quality deteriorates, a mobile terminal automatically increases the transmit power to improve the signal quality to ensure good user experience. As a result, the power consumption of the battery increases. Sources of Wi-Fi signals are mostly in the indoor range, while those of 5G signals are the outdoor base stations dozens of kilometers away. When a mobile terminal uploads data, the transmission distance of Wi-Fi signals is far less than that of 5G signals. In most cases, the communication distance of 5G is thousands of times that of Wi-Fi. This requires a great increase in the signal strength of mobile terminals, which increases the power consumption. It has been tested that if network data is used for half an hour, Wi-Fi networks can save power by 5% compared with 4G mobile networks. In addition, the latest-generation Wi-Fi 6 (802.11ax) supports the TWT function. This function can automatically wake up devices when services are required and allow the devices to automatically sleep when no service is involved, further saving power.

Nowadays, Wi-Fi is more a necessary infrastructure or central hub for enterprise digital transformation. For example, Wi-Fi networks are the central hubs of most smart retail, smart logistics, and smart office solutions. Therefore, 5G cannot completely replace Wi-Fi and is deeply integrated with Wi-Fi.