Title: Wireless Communications Basics --- Uplink/Downlink Rates, Negotiated Rate, and Actual Rate [Print this page] Author: GTAC-Sophia Time: 2023-5-29 15:17 Title: Wireless Communications Basics --- Uplink/Downlink Rates, Negotiated Rate, and Actual Rate (1) Uplink rate
The uplink rate is the rate at which data is uploaded, that is, the speed at which local information is uploaded to the network. Or, it can be seen as the transmitting rate of a terminal. (2) Downlink rate
The downlink rate is the rate at which data is downloaded, that is, the speed at which data on the network is downloaded to the local terminal. Or, it can be seen as the receiving rate of a terminal. (3) Negotiated rate
Communications entail two peer parties. The negotiated rate, as its name suggests, is the rate negotiated and agreed upon by the router and terminal. What do the router and the terminal negotiate?
They negotiate factors that affect the wireless rate, including the Wi-Fi technology (wireless protocol), modulation method, bandwidth, spatial streams, and code rate. If a router supports Wi-Fi 6, dual-band, and 4 x 4 MIMO while a phone supports Wi-Fi 6, dual-band, and 2 x 2 MIMO, the negotiation results are Wi-Fi 6, dual-band, and 2 x 2 MIMO. Whereas the negotiated rate is calculated based on these factors, it is still a theoretical rate
. (4) Actual rate
Wireless communications use the half-duplex mode which allows only data transmission or receiving at a given time. For example, the negotiated rate can be seen as the sum of the uplink and downlink rates. And in most cases, the downlink rate is greater than the uplink rate. Therefore, if the negotiated rate is 1200 Mbps, the uplink and downlink rates may be 200 and 1000 Mbps respectively. (This example is for reference only.)
That is why the measured actual rate is less than the negotiated rate. In addition, the prerequisite of the assumed negotiated, downlink and uplink rates above is that the conditions are optimal, which is nearly impossible because there are other factors affecting transmission rates as well.
Signal strength (number of walls between the router and terminal)
Interference of other router signals in the environment
Interference of other devices such as microwave ovens and refrigerators if the 2.4 GHz band is used
Other terminals connected to the router, which may occupy more resources
Messages in wireless transmission mechanisms that take up resources
These factors may reduce the theoretical rates by 10% to 40%. Therefore, if the negotiated rate is 1200 Mbps, the most possible downlink rate is about 600 Mbps. The rate may reach 800 Mbps and over if the wireless environment is very clean. In addition, the network cable specifications, port specifications, and extranet bandwidth also play a part. If the extranet bandwidth is 100 Mbps, the negotiated rate 800 Mbps is useless. (5) Rate conversion
You may wonder why your download rate is less than the labeled 100 Mbps bandwidth.
That is because of the differences between units. The differences are as follows:
1. Mb indicates megabit. 1 Mb equals 1024 Kb, just as 1 km equals 1000 m and 1 Kg equals 1000 g.
Other common conversions include: 1 Tb = 1024 Gb, 1 Gb = 1024 Mb, 1 Mb = 1024 Kb, and 1 Kb = 1024 b.
2. The letter b indicates bits. Eight bits equal one byte (B). 8 Mb/s equals 1 MB/s.
Based on these conversions, we can conclude:
100 Mb/s = (100 x 1024) Kb/s = 102400 Kb/s = (102400/8) KB/s = 12800 KB/s = (12800/1024) MB/s = 12.5 MB/s.
Common download rate units are KB/s and MB/s. Your actual download rate may be less than the labeled rate because the rate units are different.
Note: The rates raised above are theoretical values. The actual values depend on the network environment and may be less than the theoretical values.
Welcome to Ruijie Community (https://community.ruijienetworks.com/)