802.11n MCS Guide
MCS (Modulation and Coding Scheme)
The configuration of the 802.11n radio frequency rate is implemented by the MCS index value. The MCS modulation coding table is a representation proposed by 802.11n to characterize the communication rate of the WLAN. The MCS takes the factors affecting the communication rate as the columns of the table, and uses the MCS index as a row to form a rate table.
Therefore, each MCS index actually corresponds to the physical transmission rate under a set of parameters. Tables 1-4 and 1-5 list MCS rate tables with a bandwidth of 20 MHz and a bandwidth of 40 MHz, respectively.
(For a description of the full rate, see the 20.6 Parameters for HT MCSs section of the document 802.11n-2009.)
From the table below, it can be concluded that MCS 0-7 uses a single spatial stream, and when MCS=7, the rate value is the largest. MCS 8~15 uses two spatial streams. When MCS=15, the rate value is the largest.
MCS is divided into two categories: basic MCS sets, and supports MCS sets.
l Basic MCS set: The basic MCS is the MCS rate set that the AP must support. The client must meet the basic MCS rate configured by the AP to be associated with the AP.
l Supporting the MCS set: Supporting the MCS rate set is based on the basic MCS set of the AP. The AP can support a higher rate set. The user can configure the MCS rate set to allow the client to select the basic MCS. A high rate is associated with the AP.
It should be noted that when the MCS index value is configured, the input MCS index value indicates a range, that is, 0 to the configuration value. For example, if 5 is input, it indicates that the set MCS value is 0 to 5.
