Have you ever taken a look at the Wi-Fi logs generated by your router?
Or if you are on a Mac computer, have you seen the details of the Wi-Fi connection by pressing and holding the Option key while you click on the Wi-Fi icon?
Do you wonder about what do those terms that you see in those places mean? In this article, we will look at 10 Wi-Fi terms that you may come across.
HT is short for High Throughput and is the alternative name for 802.11n (Wi-Fi 4). The reason behind the name was due to the speeds improvements, which can range from anywhere between 72mbps to 600mbps, thus making it a lot faster than 802.11g (Wi-Fi 3).
The new technologies introduced with Wi-Fi 4 enable support for more antennas which in turn enable higher data rates, adding 40 MHz channel width, 5GHz band and standardising Multiple Input and Multiple Output (MIMO).
VHT or Very High Throughput is the alternative name for 802.11ac (Wi-Fi 5). It is designed to be the successor to HT. With Wi-Fi 5, wireless communication over the 5GHz band is improved with new technologies, enabling speeds ranging from anywhere between 433mbps to 6933mbps.
Some of the new technologies for Wi-Fi 5 include support for optional 160 MHz channel width and mandatory 80 MHz channel width, increasing the number of MIMO streams from 4 to 8 and 256-QAM support.
HE is short for High Efficiency and is the alternative name for 802.11ax. The reason behind this name stemmed from new technologies that improve efficiency and performance. Some of these new technologies include OFDMA and MU-MIMO. For more information about Wi-Fi 6, check out this explainer.
4. MCS Index
MCS Index or Modulation and Coding Scheme Index is a unique reference value that identifies the combination of the following:
- Number of Spatial Stream
- Modulation Type
- Coding Rate
When this value is combined with the Wi-Fi channel width, it allows you to quickly calculate the likely data rate of a given connection. Naturally, the larger the MCS index value, the better as it indicates a faster Wi-Fi connection.
NSS or Number of Spatial Stream refers to the independently and separately coded data signals that are transmitted from multiple antennas of an Access Point (AP). MIMO wireless communication use this technique to increase the throughput of a communication channel by sending and receiving multiple data signals simultaneously.
RSSI or Received Signal Strength Indication in the Wi-Fi context refers to the relative received signal strength in some arbitrary units. It is calculated from the perspective of the receiving radio. Generally, the greater the value, the stronger the signal. Therefore, it is common to see them represented in a negative form since the closer the value is to zero, the stronger the signal strength.
7. Tx Rate
Tx Rate or Transmission Rate refers to the transmission speed of the wireless communication channel from the perspective of the client device. Naturally, the higher the value, the faster the connection since more data can be sent from the client.
8. Rx Rate
Rx Rate or Receive Rate refers to the receiving speed of the wireless communication channel from the perspective of the client device. Naturally, the higher the value, the faster the connection since more data can be received by the client.
DFS or Dynamic Frequency Selection allows a wireless network to use 5GHz frequencies that are reserved for use by radar stations. Without this feature, ApPs are limited to the following 20 MHz channels:
- Channel 36
- Channel 40
- Channel 44
- Channel 48
- Channel 149
- Channel 153
- Channel 157
- Channel 161
- Channel 165
In environments such as an apartment building where multiple APs can be deployed, this can slow down network performance due to the increased wait time brought on by congestion.
With DFS, the issue of congestion is mostly resolved as APs can use 16 additional channels on the 5 GHz band, thus leading to improved performance. These 16 channels are known as DFS channels.
However, if there is a radar station nearby using any of the DFS channels, the AP will detect that and switch to one of the non-DFS channel. When that happens, client devices will temporarily lose internet connection while they re-establish connection.
MUBF or Multi-User Beam-Forming is an extension of beam-forming to support multiple receiver devices.
And what is beam-forming then?
Beamforming is a technique that allows an AP to focus radio signals towards a receiver. The AP does this by transmitting multiple radio signals from its antenna array in a manner that results in both constructive and destructive radio interferences. The destructive radio interference will cancel the transmission in the directions that have no receiver while constructive radio interference will increase the power of the transmission towards the receiver, thus improving the transmission quality and range.