diff --git a/CHANGES.md b/CHANGES.md
index 535ae0a96..3a097f6b6 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -37,6 +37,7 @@ Changes from ns-3.36 to ns-3.37
 * Adds support for **LrWpanMac** active and passive scan.
 * Add supporting association structures: parameters, callbacks and the pending transaction list to **LrWpanMac**.
 * The **TxopTrace** trace source of wifi `QosTxop` now has an additional argument (the third one) indicating the ID of the link the TXOP refers to (for non-MLDs, this value is zero).
+* The maximum allowed channel width (in MHz) for a data transmission is passed to the **GetDataTxVector** method of the `WifiRemoteStationManager`.
 
 
 ### Changes to build system
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 371e960b6..f1093006c 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -21,6 +21,7 @@ Release 3-dev
 - (internet) !996 - IPv6 Router Solicitations (RS) are now retransmitted up to 4 times, following RFC 5779.
 - (lr-wpan) !997 - Adds MAC ACTIVE and PASSIVE scan support
 - (wifi) CCA has been reworked to report the channel type in the CCA-BUSY indication and the per-20 MHz CCA bitmap for 802.11ax.
+- (wifi) PPDUs are transmitted on the largest primary channel that is found to be idle (according to the CCA-BUSY indication provided by the PHY) when gaining a TXOP.
 
 ### Bugs fixed
 
diff --git a/src/wifi/doc/source/wifi-design.rst b/src/wifi/doc/source/wifi-design.rst
index 477a3f26e..00074776b 100644
--- a/src/wifi/doc/source/wifi-design.rst
+++ b/src/wifi/doc/source/wifi-design.rst
@@ -838,6 +838,14 @@ a result, the backoff timer has a zero value, the EDCAF cannot immediately
 transmit, but it has to wait for another slotTime of idle medium before transmission
 can start.
 
+When the Channel Access Manager determines that channel access can be granted, it
+determines the largest primary channel that is considered idle based on the CCA-BUSY
+indication provided by the PHY. Such an information is passed to the Frame Exchange
+Manager, which in turn informs the Multi-User Scheduler (if any) and the Wifi Remote
+Station Manager. As a result, PPDUs are transmitted on the largest idle primary channel.
+For example, if a STA is operating on a 40 MHz channel and the secondary20 channel
+is indicated to be busy, transmissions will occur on the primary20 channel.
+
 The higher-level MAC functions are implemented in a set of other C++ classes and
 deal with: