Table of Contents

Wireless Standards

This article lists common standards and basic features that are relevant to OpenWrt.

802.11a

Old standard that operates in 5GHz frequency band

IEEE_802.11a-1999

802.11b

IEEE_802.11b-1999 Operates in 2.4GHz Band Old standard.

802.11g

IEEE_802.11g-2003 Operates in 2.4GHz Band Old standard.

802.11n

IEEE_802.11n-2009

802.11ac

IEEE_802.11ac Also called “Wifi 5”

IEEE_802.11ad Not very common in OpenWrt.

802.11ax

IEEE_802.11ax

Also called “Wifi 6”

Features in Drivers

Each hardware has certain features that can be queried in OpenWrt by using 

iw phy <phy interface> info

Mismatching features result in compatibility problems and possibly reduced data transfer rates.

example: 

RX LDPC
HT20/HT40
SM Power Save disabled
RX HT20 SGI
RX HT40 SGI
TX STBC
RX STBC 1-stream
Max AMSDU length: 3839 bytes
DSSS/CCK HT40

MIMO multiple-input and multiple-output

Technology that uses multiple antennas to increase data transfer rates. see also MCS tables

STBC is part of MIMO.

MU-MIMO

HT, VHT, HE

Required for higher throughput - 802.11n, 802.11ac, 802.11ax standards. HT ... 802.11n , VHT ... 802.11ac, HE ... 802.11ax

HT20 : 20 MHz wide channels HT40: 40 MHz VHT80 : 80 MHz VHT160: 160MHz

see also MCS table

MCS Modulation and Coding Scheme

often visualized as a table. The MCS Index is a value that the hardware supports and uses when communicating.

:!: Low data rates mean the higher indexes are not used. Reasons might be configuration or interference.

RSDB DBDC

Acronym for Radio Simultan Dual Band, Dual Band Dual Concurrent

Use two frequency bands at the same time by one endpoint.

Supported by: mt76 and potentially brcmfmac ( BCM4359 )

Normally radios operate in Single Band Single Concurrent (SBSC) (OpenWrt: 802.11an, 802.11bgn) or are capable of Dual Band Single Concurrent (DBSC): having 2 frequency bands selectable (OpenWrt: 802.11abgn capable).

WOW Wake On Wlan

Wake-on-LAN

some MCS Tables