In the past two years, with the maturity and popularity of Wi-Fi 6 and Mesh networking technology, the price of high-end routers has gradually become close to the people, from technology enthusiasts to ordinary families have used wireless routers that support a new generation of Wi-Fi technology. Especially in 2022, routers using Wi-Fi 6E technology began to enter the market, and many manufacturers also named their routers the title of "10 Gigabit Wireless Router". Such publicity will naturally make many consumers think that wireless networks are just around the corner to replace wired networks.
But is this really the case, and how fast can the so-called 10 Gigabit wireless router run? After reading this article, you should be able to have a new understanding of these questions.
Wireless network speed depends on what
The home wireless router is a highly integrated all-in-one that integrates:
Routers and Firewalls: Provides layer-three capabilities, including network access and protection from outside intrusions.
Switches: Multiple LAN ports provide Layer 2, which is a local area network (LAN) function.
Wireless access point: Access Point is abbreviated as AP, which is the function of transmitting Wi-Fi signals and allowing wireless devices to access the network.
This article focuses on the wireless access point features in home wireless routers, referred to simply as AP. Before we can talk about actual speed, we need to understand the various factors that determine Wi-Fi speed.
Wi-Fi protocol
The Wi-Fi protocol is the most recently mentioned because in the Wi-Fi 5 era and before, protocol names were named by the IEEE's 802.11 protocol rule standard, rather than simply numbers representing algebra. Until the introduction of the Wi-Fi 6 protocol in 2018, 802.11n and 802.11ac were renamed Wi-Fi 4 and Wi-Fi 5 together, so everyone's perception may not be strong.
The current generations of wi-Fi communication protocols and their corresponding 802.11 standards are as follows:
Wi-Fi 6：IEEE 802.11ax
Wi-Fi 5：IEEE 802.11ac
Wi-Fi 4：IEEE 802.11n
One of the main factors that affect Wi-Fi speed is the Wi-Fi protocol used between the AP and the terminal.
At the limits of both protocols, Wi-Fi 5 is capped at a theoretical rate of 3466 Mbps, while Wi-Fi 6 can reach up to 9600 Mbps.
Using the same terminal and wireless access point, respectively, using the Wi-Fi 5/6 protocol connection, the theoretical rate of Wi-Fi 6 is about 38% higher than that of Wi-Fi 5.
frequency
The transmission of a Wi-Fi signal depends on a certain frequency of radio waves. The Wi-Fi 6 protocol currently supports wireless signals in three frequency bands, while the Wi-Fi 6E protocol supports one more high-frequency radio wave at 6GHz:
2.4GHz: The 2.4GHz band is used in IEEE 802.11a, and 2.4GHz can achieve good coverage due to the lower frequency. It is worth noting that 2.4GHz is only supported by the Wi-Fi 4 and Wi-Fi 6 protocols.
5.2GHz/5.8GHz: These two frequency bands are generally referred to as 5GHz, and are also the most commonly used high-speed Wi-Fi frequencies, compared to 2.4GHz, the 5GHz coverage area is greatly reduced, but the speed increase is huge and has a larger frequency range, and less interference.
6GHz: 6GHz is the new frequency assigned to Wi-Fi under the Wi-Fi 6E standard, compared to 5GHz, the 6GHz band under the Wi-Fi 6E protocol does not increase in speed, but adds a large number of frequency bands, reduces the same frequency interference, and the coverage area is slightly reduced compared to 5GHz.
The higher the frequency, the greater the amount of information per unit time radio wave load, and therefore the faster the speed, with the theoretical rate of 5GHz at the same bandwidth about doubling that of 2.4GHz.
Bandwidth and MIMO
2.4GHz and 5GHz not only produce speed differences in frequency, but also in the width of the bandwidth that can be used.
Bandwidth refers to the width of the frequency band occupied by the signal. Here you can simply think of the frequency bandwidth as the number of lanes on the highway, and the more lanes there are, the greater the amount of traffic that can be driven per unit of time.
2.4GHz only supports 20Mhz and 40MHz bandwidths, while at 5GHz/6GHz, it can additionally support larger 80Mhz and 160Mhz (160Mhz only 5.2 GHz support); bandwidth and theoretical speed are linearly increasing, and the wider the bandwidth, the greater the theoretical rate.
MIMO is relatively complex to understand, but it can be simply imagined as the number of antennas, Wi-Fi technology, each antenna can be responsible for the transmission of data on a link, the more antenna transmission rate is faster. As with bandwidth, miMO can be imagined as a "stereoscopic" lane, and doubling the number of antennas will also double the throughput of Wi-Fi speeds.
Quadrature amplitude modulation QAM
In the process of wi-fi 5 to Wi-Fi 6 protocol advancements, the maximum supported protocol has increased from 256-QAM to 1024-QAM, an increase in speeds of approximately 25%.
Recently, there have also been 4k-QAM endpoints with early support, which is 20% faster than 1024-QAM.
summary
We can think of Wi-Fi as an urban road – 2.4GHz is the main road of the city, which is seriously disturbed and therefore inefficient in the center of the city; 5GHz is the city's ring highway, with fewer vehicles and no speed limit, so the data can go fast; bandwidth and MIMO are a set of three-dimensional multi-lanes, which directly increase traffic.
We integrate the above parameters to get a wireless rate formula for a wireless access point.
At 5GHz:
Wi-Fi 5 3x3 MIMO 80Mhz 256 QAM wireless access point supporting up to 1300 Mbps
Wi-Fi 6 4x4 MIMO 160Mhz 1024 QAM wireless access point supporting up to 4804 Mbps
If you increase or decrease the number of MIMO or the width of the bandwidth, the maximum rate is also proportionally reduced:
Wi-Fi 5 Wave 2 2x2 MIMO 160Mhz 256 QAM supports up to 1733 Mbps
Wi-Fi 6 4x4 MIMO 80Mhz 1024 QAM supports up to 2402 Mbps
What the parameters of the wireless router represent
Before deciphering the actual rate of the wireless network, we need to explain what the parameters of the wireless router represent.
First of all, let's take a flagship wireless router "Xiaomi AX9000" as an example:
The product name is: AX9000, where:
AX: Represents support for the highest Wi-Fi specification for IEEE 802.11ax, which is the Wi-Fi 6 protocol.
9000: Represents a maximum supported aggregate connection rate of 9000 Mbps, or 1125 MB/s transfer rate, for their hardware.
And 9000 = 4804 + 2402 + 1196 + 576, I believe this string of numbers you are not strangers, in the above has been explained in detail the Wi-Fi 6 protocol can achieve the various rates, here in detail to explain:
4804Mbps: The theoretical rate achievable at 4x4 MIMO 160MHz 1024-QAM at 5.2GHz
2402 Mbps: The theoretical rate achievable at 4x4 MIMO at 5.8GHz at 80MHz 1024-QAM
1196 Mbps: The theoretical rate achievable at 4x4 MIMO at 2.4GHz at 40MHz 1024-QAM
576 Mbps: AIoT antenna rate that cannot be used by terminals.
9000 megabytes is summed by the highest rates supported by the hardware in all supported frequency bands of the router, and is named in accordance with IEEE regulations, but this does not mean that the wireless router can run at a rate of 9000 Mbps.
The actual handshake rate is supported with the terminal
In addition, we need to pay attention to two points, one is that high-speed Wi-Fi not only requires AP support, but also terminal device support. Another point is that Wi-Fi terminals can only work in one frequency band at a time, so the maximum rate that my device can theoretically achieve on this wireless router is to choose a terminal that uses 160Mhz in the 5.2GHz band and uses 4x4 MIMO, so that the Wi-Fi rate can be negotiated to 4804Mbps under hardware conditions.
Since there is no Wi-Fi 6 terminal on the market that supports 4x4 MIMO, and the mainstream device is still 2x2 MIMO, our rate will be another discount, if you use a 160MHz-enabled mobile terminal such as the Xiaomi Mi 12 Pro, you can reach 2402Mbps.
End devices such as the iPhone, after the iPhone 11 series, all support the Wi-Fi 6 protocol, but only support 2x2 MIMO 80Mhz, so the use of iPhone 11 after the Wi-Fi 6 support terminal device, can only reach 1201Mbps.
Older devices like the MacBook Pro 16-inch 2019, which only supports 3x3 Wi-Fi 5, can only reach 1300Mbps for Wi-Fi 5.
The above rates are negotiated rates between the terminal and the router, or also known as the PHY rate or handshake rate, which must be greater than the wireless network rate that can run out in a real-world environment.
Some other "costs" of Wi-Fi
The handshake rate or PHY rate can be understood as the NEDC range of the electric vehicle, and the rate will also be discounted according to the actual environment.
Due to the complexity of Wi-Fi overhead, this article will not delve into any of the most obvious types of overhead:
TCP/IP overhead: Across all wired or wireless networks, the overhead for a TCP/IP connection is approximately 5%. That 5% comes from all the data needed to set up the connection and resolve the packets and frames being exchanged. At standard frame sizes, the TCP throughput of a wired 1Gbps connection is approximately 940-950 Mbps.
Beacon frame: This is how the AP advertises the network to the client device. To ensure that all devices in range understand them, the AP sends management traffic, such as beacon frames, at the lowest supported data rate. This expands the range of broadcasts, reduces the rate at which speeds are transmitted, and consumes valuable broadcast time.
Half-duplex: OFDM-based Wi-Fi is half-duplex, which means that only one device can be transmitted at a time, and only in one direction. Metaphorically, Wi-Fi is a walkie-talkie, not a phone, which means that only one person can talk at a time. Ethernet is full-duplex, allowing simultaneous transmission to two directions. Being Wi-Fi is half-duplex doesn't mean throughput is halved, but it does mean that Wi-Fi devices can't multitask. When downloading large files, client devices must spend many short protection intervals to transmit TCP acknowledgment frames back to their AP or allow others to transmit them. Wi-Fi devices cannot download and upload data at the same time, nor can they communicate in transit on their terminals. MU-MIMO and OFDMA technologies partially solve this problem.
Interference and retransmission: In addition to being (mostly) half-duplex, Wi-Fi is also a shared medium. When one device is transmitted over a channel, all other devices in range must wait for their turn. If multiple devices transmit at the same time, collisions may occur, resulting in chaotic transmission. When a collision occurs, the device needs to wait randomly for a period of time before it can retransmit. Coordinating the use of shared media and handling collisions consumes valuable broadcast time, resulting in lower effective throughput for everyone. For example, Bluetooth and 2.4GHz Wi-Fi will interfere with each other, and USB 3.0 will also affect 5GHz Wi-Fi signals.
Modulation differences between frames: When you see a link rate of 1200Mbps, it does not mean that each frame is sent in 1024-QAM modulation during transmission. The link rate is more like the average speed limit. As channel conditions change or transmission fails, individual frames may be sent above or below the current link rate value.
EIRP: Wireless signal transmission capability
EIRP is a parameter that describes the ability of an AP to transmit signals:
Equivalent isotropically radiated power (EIRP), or effective isotropically radiated power (EIRP), is a common concept in the field of radio communications, which refers to the radiated power of the antenna in a specified direction. Ideally equal to the transmitter's transmit power multiplied by the gain of the antenna.
Usually the signal strength is expressed in logarithmic units dBm, so EIRP = transmit power + antenna gain - loss value
The transmission power can be simply understood as how loud a person shouts, and the antenna gain can be simply understood as how much a "microphone + speaker" can amplify the sound; EIRP can be simply understood as how loud a person shouts at the microphone, and how loud the sound coming out of the speaker is.
EIRP can describe the wireless signal transmission capability of an AP to some extent. The Ministry of Industry and Information Technology of the Mainland has clear restrictions on EIRP for Wi-Fi:
At 2.4 GHz, EIRP is limited to 100mW, which is 20dBm
At 5 GHz, the EIRP is limited to less than 200mW, which is 23dBm
It should be noted that the power limit here is the total power of all the antennas of the AP, so when multiple antennas are working at the same time, the transmit power of each antenna will be reduced accordingly. The effect is that Wi-Fi reduces the rate of the connection.
Wall barrier, distance and signal strength
Signal strength is also one of the important reasons that affect the actual Wi-Fi speed, and the signal received by our terminal is also expressed in logarithmic units dBm like EIRP, but because the actual signal received is very depreciated, the 5GHz signal of -30 ~ -25 dBm can generally be accepted within one meter (no occlusion) around the AP.
In the space, you can refer to the following figure:
Non-load-bearing concrete walls in domestic houses cause 12-20dBm attenuation of the signal, while load-bearing walls are more:
The sensitivity of wireless network bandwidth and modulation technology is as follows:
So these factors affect the Wi-Fi rate, we don't have to do too much combined calculation, just need to know that in an ideal environment, the actual connection speed is up to about 70%-80% of the theoretical speed, in normal environment:
A 2x2 device on an 80 MHz channel can achieve a maximum negotiation rate of 1201 Mbps, with an actual throughput of approximately 800-900 Mbps.
A 2x2 device on a 160 MHz channel can achieve a maximum negotiation rate of 2402 Mbps, with an actual throughput of approximately 1400-1600 Mbps.
See here I believe that you have a certain concept of the actual transmission rate with Wi-Fi, back to the beginning of this article, 10 Gigabit wireless router can really run out of 10 Gigabit, the answer is definitely no: now the wireless routers on the market due to their naming rules, are aggregation rates, in actual use of the best terminal equipment with the best AP can only reach 1.4Gbps-1.6Gbps transmission speed in the ideal environment.
When multiple devices (2x2 160Mhz Wi-Fi 6) use the same AP for switching throughput at the same time, they are also limited by the switching capacity of the AP and the limitation of antenna power consumption, and can only reach 1Gbps speed.
All of the scenarios discussed in this article are in a more ideal environment, where the real-life Wi-Fi transmission process is more complex than the ideal environment, and more frequency band interference and more signal-to-noise ratios are significant factors affecting Wi-Fi speed.
In the next article, I will talk about how to optimize the home Wi-Fi environment and how to optimize the roaming efficiency between multiple APs, and I believe that it can solve common wireless network problems such as HomePod stereo disconnection and game dropout to a certain extent.
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