The theoretical OTA data rate could refer to How to Calculate Wi-Fi Data Rate?
But actually the Wi-Fi data rate in our real-world use case is always lower than the OTA rate. Why?
● Signal Strength
Wi-Fi signal strength correlates with speed — the better the signal, the higher the speed. In real-world use, however, signal quality is inevitably degraded by the surrounding environment, due to factors such as obstruction by physical barriers and distance.
Signal Strength is the most key parameter from the Wi-Wi signal TX souce to signal RX sink, including TX power, the path distance and the physical barriers between transimitter and receiver, the sensitivity of the receivers.
● Signal Interference
In the real circumstance, other wireless devices, electronic equipment, and metal objects can all generate electromagnetic interference that affects the stability of the wireless network. Specially the interference’s frequency is close to 2.4GHz and 5.8GHz of Wi-Fi working frequecny. The more interference sources there are, the more easily network stability is compromised.
● Bandwidth Provided by the ISP
If the broadband service provided by your ISP is only 100M, then the Wi-Fi speed available in your home cannot possibly exceed 100M. The 300M or 450M wireless transmission rates we often hear about refer to throughput within the local network; your actual internet speed is determined primarily by the external bandwidth supplied by your ISP.
So ISP bandwidth will determine what WAN bitrate during you choose the Router. If ISP broadband is only 100Mbps, then 100Mbps WAN & LAN router is enough. If ISP broadband is about 300Mbps/500Mbps/1000Mbps, then 1Gbps WAN & LAN router is necessary.
● Limitations of the Client Device’s Wireless NIC
When a wireless device (such as a smartphone or laptop) connects to a Wi-Fi signal, it negotiates a wireless transmission rate with the optical modem (ONT) or router. The higher the rate supported by the device’s wireless NIC, the higher the negotiated transmission rate will be.
For example, if the smartphones currently have wireless NICs supporting 150Mbit/s, while most laptops come with wireless NICs supporting 300Mbit/s. This means that even when connected to a 450M wireless router, the theoretical maximum wireless transmission rate a laptop can achieve is 150 Mbit/s.
In addition, the age of the wireless NIC driver may also affect the transmission rate.
● Network Congestion
When many users connect to the same network simultaneously, the network can become congested, resulting in slower speeds. This is especially true when the number of connected users exceeds the network’s capacity, which can cause noticeable lag and stuttering.
The simultaneous connecting devices/users are determined by the routers antennas’ Qty (nTnR) and Its RU (Resource Units of Subcarrier) in WiFi6.