Is there any way to disable or bypass CSMA/CA in esp8266? I don't want my packets to wait for channel to be clear. I want them to be transmitted at predefined time. If it is not possible to completely disable it, can we change random back-off period (so that we can transmit packets sooner rather than waiting for long time)? If not in esp8266 is there such functionality (of disabling CSMA/CA) in any other IC implementing WiFi protocol in 2.4 GHz band?

Edit: http://www.osbridge.com/download/OSBRiDGE_5G.pdf allows disabling CSMA/CA but it works in 5 GHz band. MikroTik also allows disabling CSMA/CA https://wiki.mikrotik.com/wiki/Manual:Interface/Wireless.

  • \$\begingroup\$ Is it mentioned in the datasheet? \$\endgroup\$
    – Eugene Sh.
    Aug 14, 2017 at 14:18
  • \$\begingroup\$ no, its not mentioned. \$\endgroup\$
    – Ashutosh
    Aug 14, 2017 at 14:19
  • \$\begingroup\$ Why do you want that? If the channel is not clear it won't be received. \$\endgroup\$ Aug 14, 2017 at 14:23
  • \$\begingroup\$ we are more concerned about transmitting packets at regular intervals than receiving them correctly. Even if some packets get dropped, it does not matter much in our application. \$\endgroup\$
    – Ashutosh
    Aug 14, 2017 at 14:30
  • 1
    \$\begingroup\$ Once you do that, it's no longer WiFi. Note that if you transmit without waiting you will not only lose your packet but jam someone else's! \$\endgroup\$
    – pjc50
    Aug 14, 2017 at 14:51

1 Answer 1


There is a way to disable it using rom_chip_v5_disable_cca() function defined at address 0x400060d0 in the boot ROM of esp8266 (/tools/sdk/ld/eagle.rom.addr.v6.ld file in esp8266 Arduino core gives idea about it ).

Although option to disable CCA is provided by some 802.11 chipsets and some operating systems, I would recommend not to disable it. It's one of the most important feature of WiFi protocol and disabling it just increases the number of packet drops as experiments suggest. The other functionalities of the wifi also become unpredictable.


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