wifi: (fixes #1104) Fix computation of reordering buffer start SeqN

Reported and fix suggested by Charles Huang

RELEASE_NOTES.md

@@ -61,6 +61,7 @@ The required Doxygen version for documentation generation is version 1.11.
 - (wifi) Fix S-MPDU TX duration computation with BlockAck ack policy
 - (wifi) Fix missing DSSS Param Set in Probe Request sent over 2.4 GHz links
 - (spectrum) Trigger 3GPP channel updates after changes to antenna attributes
+- (wifi) #1104 - Fix wrong calculation of start sequence number
 
 ## Release 3.43
 

src/wifi/model/recipient-block-ack-agreement.cc

@@ -159,8 +159,10 @@ RecipientBlockAckAgreement::NotifyReceivedMpdu(Ptr<const WifiMpdu> mpdu)
         // MAC process in order of increasing Sequence Number subfield value. Gaps may
         // exist in the Sequence Number subfield values of the MSDUs or A-MSDUs that are
         // passed up to the next MAC process.
-        PassBufferedMpdusWithSeqNumberLessThan(mpdu->GetHeader().GetSequenceNumber() - m_winSizeB +
-                                               1);
+        const uint16_t newWinStartB =
+            (mpdu->GetHeader().GetSequenceNumber() - m_winSizeB + 1 + SEQNO_SPACE_SIZE) %
+            SEQNO_SPACE_SIZE;
+        PassBufferedMpdusWithSeqNumberLessThan(newWinStartB);
 
         // 5. Pass MSDUs or A-MSDUs stored in the buffer up to the next MAC process in
         // order of increasing value of the Sequence Number subfield starting with