From 9db609a973ee476b9378d012457ea93296dcf65a Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Mon, 5 Jan 2026 16:50:47 +0100
Subject: [PATCH 01/11] drivers/netdev_ieee802154_submac: remove softack

---
 cpu/native/Makefile.dep                       |  1 -
 cpu/nrf52/Makefile.dep                        |  1 -
 .../netdev_ieee802154_submac/Makefile.include |  1 -
 .../netdev_ieee802154_submac.c                | 25 +------------------
 4 files changed, 1 insertion(+), 27 deletions(-)
 delete mode 100644 drivers/netdev_ieee802154_submac/Makefile.include

diff --git a/cpu/native/Makefile.dep b/cpu/native/Makefile.dep
index 217f00ada2d9..54a9b085416f 100644
--- a/cpu/native/Makefile.dep
+++ b/cpu/native/Makefile.dep
@@ -43,7 +43,6 @@ ifneq (,$(filter socket_zep,$(USEMODULE)))
   USEMODULE += ieee802154
   ifneq (,$(filter netdev,$(USEMODULE)))
     USEMODULE += netdev_ieee802154_submac
-    USEMODULE += netdev_ieee802154_submac_soft_ack
   endif
 endif
 
diff --git a/cpu/nrf52/Makefile.dep b/cpu/nrf52/Makefile.dep
index e474509e6aae..52a3444b4fdc 100644
--- a/cpu/nrf52/Makefile.dep
+++ b/cpu/nrf52/Makefile.dep
@@ -14,7 +14,6 @@ ifneq (,$(filter nrf802154,$(USEMODULE)))
   USEMODULE += luid
   ifneq (,$(filter netdev,$(USEMODULE)))
     USEMODULE += netdev_ieee802154_submac
-    USEMODULE += netdev_ieee802154_submac_soft_ack
   endif
 endif
 
diff --git a/drivers/netdev_ieee802154_submac/Makefile.include b/drivers/netdev_ieee802154_submac/Makefile.include
deleted file mode 100644
index 3b3230fef92c..000000000000
--- a/drivers/netdev_ieee802154_submac/Makefile.include
+++ /dev/null
@@ -1 +0,0 @@
-PSEUDOMODULES += netdev_ieee802154_submac_soft_ack
diff --git a/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c b/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
index 0205f605f620..3d37367526f7 100644
--- a/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
+++ b/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
@@ -303,30 +303,7 @@ static int _recv(netdev_t *netdev, void *buf, size_t len, void *info)
 
         netdev_rx_info->lqi = rx_info.lqi;
     }
-#if IS_USED(MODULE_NETDEV_IEEE802154_SUBMAC_SOFT_ACK)
-    const uint8_t *mhr = buf;
-    if ((mhr[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
-        (mhr[0] & IEEE802154_FCF_ACK_REQ)) {
-        ieee802154_filter_mode_t mode;
-        if (!ieee802154_radio_has_capability(&submac->dev, IEEE802154_CAP_AUTO_ACK) &&
-            (ieee802154_radio_get_frame_filter_mode(&submac->dev, &mode) < 0
-                || mode == IEEE802154_FILTER_ACCEPT)) {
-            /* send ACK if not handled by the driver and not in promiscuous mode */
-            uint8_t ack[IEEE802154_ACK_FRAME_LEN - IEEE802154_FCS_LEN]
-                = { IEEE802154_FCF_TYPE_ACK, 0x00, ieee802154_get_seq(mhr) };
-            iolist_t io = {
-                .iol_base = ack,
-                .iol_len = sizeof(ack),
-                .iol_next = NULL
-            };
-            DEBUG("IEEE802154 submac: Sending ACK\n");
-            int snd = _send(netdev, &io);
-            if (snd < 0) {
-                DEBUG("IEEE802154 submac: failed to send ACK (%d)\n", snd);
-            }
-        }
-    }
-#endif
+
     return res;
 }
 

From 55d81be2acbe626939010886af5a60a9bb19d22f Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Mon, 5 Jan 2026 16:52:22 +0100
Subject: [PATCH 02/11] sys/net/link_layer/ieee802154/submac: add tx ack logic

---
 sys/net/link_layer/ieee802154/submac.c | 78 +++++++++++++++++---------
 1 file changed, 51 insertions(+), 27 deletions(-)

diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index d5f5a9a2cad5..ed67e4f54ccb 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -67,6 +67,11 @@ static inline bool _does_handle_ack(ieee802154_dev_t *dev)
            ieee802154_radio_has_irq_ack_timeout(dev);
 }
 
+static inline bool _does_send_ack(ieee802154_dev_t *dev)
+{
+    return ieee802154_radio_has_capability(dev, IEEE802154_CAP_AUTO_ACK);
+}
+
 static inline bool _does_handle_csma(ieee802154_dev_t *dev)
 {
     return ieee802154_radio_has_frame_retrans(dev) ||
@@ -185,26 +190,55 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
         return IEEE802154_FSM_STATE_PREPARE;
     case IEEE802154_FSM_EV_RX_DONE:
         /* Make sure it's not an ACK frame */
-        while (ieee802154_radio_set_idle(&submac->dev, false) < 0) {}
-        if (ieee802154_radio_len(&submac->dev) > (int)IEEE802154_MIN_FRAME_LEN) {
+        while (ieee802154_radio_set_idle(dev, false) < 0) {}
+        if (ieee802154_radio_len(dev) > (int)IEEE802154_MIN_FRAME_LEN) {
+            /* An ACK is sent synchronous to prevent that the upper layer (IPv6)
+               can initiate the next transmission which would fail because the transceiver
+               is still busy. */
+            if (_does_send_ack(dev)) {
+                return IEEE802154_FSM_STATE_IDLE;
+            }
+            uint8_t buf[IEEE802154_FRAME_LEN_MAX];
+            ieee802154_radio_read(dev, buf, IEEE802154_FRAME_LEN_MAX, NULL);
+            ieee802154_filter_mode_t mode;
+            if ((buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
+                (buf[0] & IEEE802154_FCF_ACK_REQ) &&
+                (ieee802154_radio_get_frame_filter_mode(dev, &mode) < 0 ||
+                mode == IEEE802154_FILTER_ACCEPT)) {
+
+                uint8_t ack[IEEE802154_ACK_FRAME_LEN - IEEE802154_FCS_LEN]
+                    = { IEEE802154_FCF_TYPE_ACK, 0x00, ieee802154_get_seq(buf) };
+                iolist_t iolist = {
+                    .iol_base = ack,
+                    .iol_len = sizeof(ack),
+                    .iol_next = NULL
+                };
+                submac->wait_for_ack = 0;
+                submac->psdu = &iolist;
+                submac->retrans = 0;
+                submac->csma_retries_nb = 0;
+                submac->backoff_mask = (1 << submac->be.min) - 1;
+                DEBUG("IEEE802154 submac: Sending ACK\n");
+                _handle_fsm_ev_tx_ack(submac);
+            }
             submac->cb->rx_done(submac);
             return IEEE802154_FSM_STATE_IDLE;
         }
         else {
-            ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
+            ieee802154_radio_read(dev, NULL, 0, NULL);
 
             /* If the radio doesn't support RX Continuous, go to RX */
-            res = ieee802154_radio_set_rx(&submac->dev);
+            res = ieee802154_radio_set_rx(dev);
             assert(res >= 0);
 
             /* Keep on current state */
             return IEEE802154_FSM_STATE_RX;
         }
     case IEEE802154_FSM_EV_CRC_ERROR:
-        while (ieee802154_radio_set_idle(&submac->dev, false) < 0) {}
-        ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
+        while (ieee802154_radio_set_idle(dev, false) < 0) {}
+        ieee802154_radio_read(dev, NULL, 0, NULL);
         /* If the radio doesn't support RX Continuous, go to RX */
-        res = ieee802154_radio_set_rx(&submac->dev);
+        res = ieee802154_radio_set_rx(dev);
         assert(res >= 0);
         /* Keep on current state */
         return IEEE802154_FSM_STATE_RX;
@@ -231,16 +265,7 @@ static ieee802154_fsm_state_t _fsm_state_idle(ieee802154_submac_t *submac, ieee8
 
     switch (ev) {
     case IEEE802154_FSM_EV_REQUEST_TX:
-        /* An ACK is sent synchronous to prevent that the upper layer (IPv6)
-           can initiate the next transmission which would fail because the transceiver
-           is still busy. */
-        if (submac->psdu->iol_len == IEEE802154_ACK_FRAME_LEN - IEEE802154_FCS_LEN &&
-            (((uint8_t *)submac->psdu->iol_base)[0] & IEEE802154_FCF_TYPE_ACK) &&
-            submac->psdu->iol_next == NULL) {
-            _handle_fsm_ev_tx_ack(submac);
-            return IEEE802154_FSM_STATE_IDLE;
-        }
-        else if (_handle_fsm_ev_request_tx(submac) < 0) {
+        if (_handle_fsm_ev_request_tx(submac) < 0) {
             return IEEE802154_FSM_STATE_IDLE;
         }
         return IEEE802154_FSM_STATE_PREPARE;
@@ -257,7 +282,7 @@ static ieee802154_fsm_state_t _fsm_state_idle(ieee802154_submac_t *submac, ieee8
          * and TX_DONE. We simply discard the frame and keep the state as
          * it is
          */
-        ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
+        ieee802154_radio_read(dev, NULL, 0, NULL);
         return IEEE802154_FSM_STATE_IDLE;
     default:
         break;
@@ -299,7 +324,7 @@ static ieee802154_fsm_state_t _fsm_state_prepare(ieee802154_submac_t *submac,
          * and TX_DONE. We simply discard the frame and keep the state as
          * it is
          */
-        ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
+        ieee802154_radio_read(dev, NULL, 0, NULL);
         return IEEE802154_FSM_STATE_PREPARE;
     default:
         break;
@@ -319,13 +344,13 @@ static ieee802154_fsm_state_t _fsm_state_tx_process_tx_done(ieee802154_submac_t
 
     switch (info->status) {
     case TX_STATUS_FRAME_PENDING:
-        assert(_does_handle_ack(&submac->dev));
+        assert(_does_handle_ack(dev));
     /* FALL-THRU */
     case TX_STATUS_SUCCESS:
         submac->csma_retries_nb = 0;
         /* If the radio handles ACK, the TX_DONE event marks completion of
         * the transmission procedure. Report TX done to the upper layer */
-        if (_does_handle_ack(&submac->dev) || !submac->wait_for_ack) {
+        if (_does_handle_ack(dev) || !submac->wait_for_ack) {
             return _tx_end(submac, info->status, info);
         }
         /* If the radio doesn't handle ACK, set the transceiver state to RX_ON
@@ -341,7 +366,7 @@ static ieee802154_fsm_state_t _fsm_state_tx_process_tx_done(ieee802154_submac_t
         }
         break;
     case TX_STATUS_NO_ACK:
-        assert(_does_handle_ack(&submac->dev));
+        assert(_does_handle_ack(dev));
         submac->csma_retries_nb = 0;
         return _handle_tx_no_ack(submac);
     case TX_STATUS_MEDIUM_BUSY:
@@ -349,7 +374,7 @@ static ieee802154_fsm_state_t _fsm_state_tx_process_tx_done(ieee802154_submac_t
          * procedure failed. We finish the SubMAC operation and report
          * medium busy
          */
-        if (_does_handle_csma(&submac->dev)
+        if (_does_handle_csma(dev)
             || submac->csma_retries_nb++ >= submac->csma_retries) {
             return _tx_end(submac, info->status, info);
         }
@@ -493,10 +518,9 @@ int ieee802154_send(ieee802154_submac_t *submac, const iolist_t *iolist)
         DEBUG("IEEE802154 submac: ieee802154_send(): Tx frame failed %s\n", str_states[current_state]);
         return -EBUSY;
     }
-    if (is_ack && ieee802154_submac_process_ev(submac, IEEE802154_FSM_EV_REQUEST_TX)
-             != IEEE802154_FSM_STATE_IDLE) {
-        DEBUG("IEEE802154 submac: ieee802154_send(): Tx ACK failed %s\n", str_states[current_state]);
-        return -EBUSY;
+    if (is_ack) {
+        DEBUG("IEEE802154 submac: ieee802154_send(): Tx ACK not permitted \n");
+        return -EPERM;
     }
     return 0;
 }

From a07216b37491107a8fe7011c9373a15a23db31aa Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Tue, 6 Jan 2026 16:12:47 +0100
Subject: [PATCH 03/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/net/link_layer/ieee802154/submac.c | 37 +++++++++++++-------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index ed67e4f54ccb..2f369e76051e 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -153,7 +153,7 @@ static ieee802154_fsm_state_t _fsm_state_prepare(ieee802154_submac_t *submac,
 static ieee802154_fsm_state_t _fsm_state_tx(ieee802154_submac_t *submac,
                                             ieee802154_fsm_ev_t ev);
 
-static int _handle_fsm_ev_tx_ack(ieee802154_submac_t *submac)
+static int _handle_fsm_ev_tx_ack(ieee802154_submac_t *submac, uint8_t seq_num)
 {
     ieee802154_dev_t *dev = &submac->dev;
 
@@ -165,6 +165,19 @@ static int _handle_fsm_ev_tx_ack(ieee802154_submac_t *submac)
     if ((res = ieee802154_radio_write(dev, submac->psdu)) < 0) {
         return res;
     }
+    uint8_t ack[]
+         = { IEEE802154_FCF_TYPE_ACK, 0x00,  seq_num };
+    iolist_t iolist = {
+        .iol_base = ack,
+        .iol_len = sizeof(ack),
+        .iol_next = NULL
+    };
+    submac->wait_for_ack = 0;
+    submac->psdu = &iolist;
+    submac->retrans = 0;
+    submac->csma_retries_nb = 0;
+    submac->backoff_mask = (1 << submac->be.min) - 1;
+    DEBUG("IEEE802154 submac: Sending ACK\n");
     /* skip async Tx request */
     _fsm_state_prepare(submac, IEEE802154_FSM_EV_BH, IEEE802154_FCF_TYPE_ACK);
     /* wait for Tx done */
@@ -192,9 +205,6 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
         /* Make sure it's not an ACK frame */
         while (ieee802154_radio_set_idle(dev, false) < 0) {}
         if (ieee802154_radio_len(dev) > (int)IEEE802154_MIN_FRAME_LEN) {
-            /* An ACK is sent synchronous to prevent that the upper layer (IPv6)
-               can initiate the next transmission which would fail because the transceiver
-               is still busy. */
             if (_does_send_ack(dev)) {
                 return IEEE802154_FSM_STATE_IDLE;
             }
@@ -205,21 +215,10 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
                 (buf[0] & IEEE802154_FCF_ACK_REQ) &&
                 (ieee802154_radio_get_frame_filter_mode(dev, &mode) < 0 ||
                 mode == IEEE802154_FILTER_ACCEPT)) {
-
-                uint8_t ack[IEEE802154_ACK_FRAME_LEN - IEEE802154_FCS_LEN]
-                    = { IEEE802154_FCF_TYPE_ACK, 0x00, ieee802154_get_seq(buf) };
-                iolist_t iolist = {
-                    .iol_base = ack,
-                    .iol_len = sizeof(ack),
-                    .iol_next = NULL
-                };
-                submac->wait_for_ack = 0;
-                submac->psdu = &iolist;
-                submac->retrans = 0;
-                submac->csma_retries_nb = 0;
-                submac->backoff_mask = (1 << submac->be.min) - 1;
-                DEBUG("IEEE802154 submac: Sending ACK\n");
-                _handle_fsm_ev_tx_ack(submac);
+                /* An ACK is sent synchronously to prevent that the upper layer (IPv6)
+                   can initiate the next transmission which would fail because the transceiver
+                   is still busy. */
+                _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(buf));
             }
             submac->cb->rx_done(submac);
             return IEEE802154_FSM_STATE_IDLE;

From ec68e3a75035945c6fea689a0906f7443c5e23ad Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Fri, 9 Jan 2026 10:05:14 +0100
Subject: [PATCH 04/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/include/net/ieee802154/submac.h    | 20 ++++++++++++--------
 sys/net/link_layer/ieee802154/submac.c | 14 +++++++++-----
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 6c340d459374..7425f675f77e 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -208,6 +208,9 @@ struct ieee802154_submac {
     ieee802154_fsm_state_t fsm_state;    /**< State of the SubMAC */
     ieee802154_phy_mode_t phy_mode;     /**< IEEE 802.15.4 PHY mode */
     const iolist_t *psdu;               /**< stores the current PSDU */
+    uint8_t rx_buf[IEEE802154_FRAME_LEN_MAX]; /**< stores received frame */
+    size_t rx_len;                      /**< stores length of received frame */
+    ieee802154_rx_info_t rx_info;       /**< stores lqi and rssi of received frame */
 };
 
 /**
@@ -410,16 +413,13 @@ static inline int ieee802154_set_tx_power(ieee802154_submac_t *submac,
 /**
  * @brief Get the received frame length
  *
- * @pre this function MUST be called either inside @ref ieee802154_submac_cb_t::rx_done
- *      or in SLEEP state.
- *
  * @param[in] submac pointer to the SubMAC
  *
  * @return length of the PSDU (excluding FCS length)
  */
 static inline int ieee802154_get_frame_length(ieee802154_submac_t *submac)
 {
-    return ieee802154_radio_len(&submac->dev);
+    return submac->rx_len;
 }
 
 /**
@@ -427,9 +427,6 @@ static inline int ieee802154_get_frame_length(ieee802154_submac_t *submac)
  *
  * This functions reads the received PSDU from the device (excluding FCS)
  *
- * @pre this function MUST be called either inside @ref ieee802154_submac_cb_t::rx_done
- *      or in SLEEP state.
- *
  * @param[in] submac pointer to the SubMAC descriptor
  * @param[out] buf buffer to write into. If NULL, the packet is discarded
  * @param[in] len length of the buffer
@@ -441,7 +438,14 @@ static inline int ieee802154_get_frame_length(ieee802154_submac_t *submac)
 static inline int ieee802154_read_frame(ieee802154_submac_t *submac, void *buf,
                                         size_t len, ieee802154_rx_info_t *info)
 {
-    return ieee802154_radio_read(&submac->dev, buf, len, info);
+    if (submac->rx_len > len) {
+        return -ENOBUFS;
+    }
+    if (info != NULL) {
+        memcpy(info, &submac->rx_info, sizeof(ieee802154_rx_info_t));
+    }
+    memcpy(buf, submac->rx_buf, submac->rx_len);
+    return submac->rx_len;
 }
 
 /**
diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index 2f369e76051e..c8957ea4a402 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -208,17 +208,16 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
             if (_does_send_ack(dev)) {
                 return IEEE802154_FSM_STATE_IDLE;
             }
-            uint8_t buf[IEEE802154_FRAME_LEN_MAX];
-            ieee802154_radio_read(dev, buf, IEEE802154_FRAME_LEN_MAX, NULL);
+            submac->rx_len = ieee802154_radio_read(dev, submac->rx_buf, IEEE802154_FRAME_LEN_MAX, &submac->rx_info);
             ieee802154_filter_mode_t mode;
-            if ((buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
-                (buf[0] & IEEE802154_FCF_ACK_REQ) &&
+            if ((submac->rx_buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
+                (submac->rx_buf[0] & IEEE802154_FCF_ACK_REQ) &&
                 (ieee802154_radio_get_frame_filter_mode(dev, &mode) < 0 ||
                 mode == IEEE802154_FILTER_ACCEPT)) {
                 /* An ACK is sent synchronously to prevent that the upper layer (IPv6)
                    can initiate the next transmission which would fail because the transceiver
                    is still busy. */
-                _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(buf));
+                _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(submac->rx_buf));
             }
             submac->cb->rx_done(submac);
             return IEEE802154_FSM_STATE_IDLE;
@@ -734,6 +733,11 @@ int ieee802154_submac_init(ieee802154_submac_t *submac, const network_uint16_t *
 
     submac->fsm_state = IEEE802154_FSM_STATE_RX;
 
+    submac->rx_len = 0;
+    submac->rx_info.rssi = 0;
+    submac->rx_info.lqi = 0;
+    memset(submac->rx_buf, 0, sizeof(submac->rx_buf));
+
     int res;
 
     if ((res = ieee802154_radio_request_on(dev)) < 0) {

From 4a88e62ff804c35688128b2c7a0f1d78a20be19a Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Fri, 9 Jan 2026 13:10:19 +0100
Subject: [PATCH 05/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/net/link_layer/ieee802154/submac.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index c8957ea4a402..e538f8efd219 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -208,7 +208,10 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
             if (_does_send_ack(dev)) {
                 return IEEE802154_FSM_STATE_IDLE;
             }
-            submac->rx_len = ieee802154_radio_read(dev, submac->rx_buf, IEEE802154_FRAME_LEN_MAX, &submac->rx_info);
+            submac->rx_len = ieee802154_radio_len(dev);
+            assert(submac->rx_len < IEEE802154_FRAME_LEN_MAX);
+            res = ieee802154_radio_read(dev, submac->rx_buf, submac->rx_len, &submac->rx_info);
+            assert(res == (int)submac->rx_len);
             ieee802154_filter_mode_t mode;
             if ((submac->rx_buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
                 (submac->rx_buf[0] & IEEE802154_FCF_ACK_REQ) &&

From 87b185e45028c0bb358aae7eaa70ac7e8acda296 Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Fri, 9 Jan 2026 13:51:23 +0100
Subject: [PATCH 06/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c | 2 +-
 sys/include/net/ieee802154/submac.h                         | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c b/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
index 3d37367526f7..aa48fbf6bcfa 100644
--- a/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
+++ b/drivers/netdev_ieee802154_submac/netdev_ieee802154_submac.c
@@ -286,7 +286,7 @@ static int _recv(netdev_t *netdev, void *buf, size_t len, void *info)
                                                              netdev_ieee802154_submac_t,
                                                              dev);
     ieee802154_submac_t *submac = &netdev_submac->submac;
-    ieee802154_rx_info_t rx_info;
+    ieee802154_rx_info_t rx_info = { 0 };
 
     if (buf == NULL && len == 0) {
         return ieee802154_get_frame_length(submac);
diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 7425f675f77e..6c95df152814 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -442,7 +442,8 @@ static inline int ieee802154_read_frame(ieee802154_submac_t *submac, void *buf,
         return -ENOBUFS;
     }
     if (info != NULL) {
-        memcpy(info, &submac->rx_info, sizeof(ieee802154_rx_info_t));
+        info->rssi = submac->rx_info.rssi;
+        info->lqi = submac->rx_info.lqi;
     }
     memcpy(buf, submac->rx_buf, submac->rx_len);
     return submac->rx_len;

From 39b35fa84193d7cdc20bc626799ab0761f63d5db Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Thu, 15 Jan 2026 14:34:55 +0100
Subject: [PATCH 07/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/include/net/ieee802154/submac.h    |  1 +
 sys/net/link_layer/ieee802154/submac.c | 97 +++++++++++++++-----------
 2 files changed, 57 insertions(+), 41 deletions(-)

diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 6c95df152814..7a3a0531c4ec 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -167,6 +167,7 @@ typedef enum {
    IEEE802154_FSM_STATE_PREPARE,        /**< The SubMAC is preparing the next transmission */
    IEEE802154_FSM_STATE_TX,             /**< The SubMAC is currently transmitting a frame */
    IEEE802154_FSM_STATE_WAIT_FOR_ACK,   /**< The SubMAC is waiting for an ACK frame */
+   IEEE802154_FSM_STATE_TX_ACK,         /**< The SubMAC is transmitting an ACK frame */
    IEEE802154_FSM_STATE_NUMOF,          /**< Number of SubMAC FSM states */
 } ieee802154_fsm_state_t;
 
diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index e538f8efd219..f7b27f410f25 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -48,6 +48,7 @@ static char *str_states[IEEE802154_FSM_STATE_NUMOF] = {
     "PREPARE",
     "TX",
     "WAIT_FOR_ACK",
+    "TX_ACK",
 };
 
 static char *str_ev[IEEE802154_FSM_EV_NUMOF] = {
@@ -155,16 +156,6 @@ static ieee802154_fsm_state_t _fsm_state_tx(ieee802154_submac_t *submac,
 
 static int _handle_fsm_ev_tx_ack(ieee802154_submac_t *submac, uint8_t seq_num)
 {
-    ieee802154_dev_t *dev = &submac->dev;
-
-    /* Set state to TX_ON */
-    int res;
-    if ((res = ieee802154_radio_set_idle(dev, false)) < 0) {
-        return res;
-    }
-    if ((res = ieee802154_radio_write(dev, submac->psdu)) < 0) {
-        return res;
-    }
     uint8_t ack[]
          = { IEEE802154_FCF_TYPE_ACK, 0x00,  seq_num };
     iolist_t iolist = {
@@ -177,14 +168,10 @@ static int _handle_fsm_ev_tx_ack(ieee802154_submac_t *submac, uint8_t seq_num)
     submac->retrans = 0;
     submac->csma_retries_nb = 0;
     submac->backoff_mask = (1 << submac->be.min) - 1;
+
     DEBUG("IEEE802154 submac: Sending ACK\n");
-    /* skip async Tx request */
-    _fsm_state_prepare(submac, IEEE802154_FSM_EV_BH, IEEE802154_FCF_TYPE_ACK);
-    /* wait for Tx done */
-    while (_fsm_state_tx(submac, IEEE802154_FSM_EV_TX_DONE) == IEEE802154_FSM_STATE_INVALID) {
-        DEBUG("IEEE802154 submac: wait until ACK sent\n");
-    }
-    return 0;
+
+    return _handle_fsm_ev_request_tx(submac);
 }
 
 static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802154_fsm_ev_t ev)
@@ -202,25 +189,26 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
         }
         return IEEE802154_FSM_STATE_PREPARE;
     case IEEE802154_FSM_EV_RX_DONE:
-        /* Make sure it's not an ACK frame */
         while (ieee802154_radio_set_idle(dev, false) < 0) {}
+        submac->rx_len = ieee802154_radio_len(dev);
+        assert(submac->rx_len < IEEE802154_FRAME_LEN_MAX);
+        res = ieee802154_radio_read(dev, submac->rx_buf, submac->rx_len, &submac->rx_info);
+        assert(res == (int)submac->rx_len);
+        /* Make sure it's not an ACK frame */
         if (ieee802154_radio_len(dev) > (int)IEEE802154_MIN_FRAME_LEN) {
-            if (_does_send_ack(dev)) {
-                return IEEE802154_FSM_STATE_IDLE;
-            }
-            submac->rx_len = ieee802154_radio_len(dev);
-            assert(submac->rx_len < IEEE802154_FRAME_LEN_MAX);
-            res = ieee802154_radio_read(dev, submac->rx_buf, submac->rx_len, &submac->rx_info);
-            assert(res == (int)submac->rx_len);
-            ieee802154_filter_mode_t mode;
-            if ((submac->rx_buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
-                (submac->rx_buf[0] & IEEE802154_FCF_ACK_REQ) &&
-                (ieee802154_radio_get_frame_filter_mode(dev, &mode) < 0 ||
-                mode == IEEE802154_FILTER_ACCEPT)) {
-                /* An ACK is sent synchronously to prevent that the upper layer (IPv6)
-                   can initiate the next transmission which would fail because the transceiver
-                   is still busy. */
-                _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(submac->rx_buf));
+            if (!_does_send_ack(dev)) {
+                ieee802154_filter_mode_t mode;
+                if ((submac->rx_buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
+                    (submac->rx_buf[0] & IEEE802154_FCF_ACK_REQ) &&
+                    (ieee802154_radio_get_frame_filter_mode(dev, &mode) < 0 ||
+                    mode == IEEE802154_FILTER_ACCEPT)) {
+                        res = _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(submac->rx_buf));
+                        submac->cb->rx_done(submac);
+                        if (res < 0) {
+                            return IEEE802154_FSM_STATE_IDLE;
+                        }
+                        return IEEE802154_FSM_STATE_TX_ACK;
+                }
             }
             submac->cb->rx_done(submac);
             return IEEE802154_FSM_STATE_IDLE;
@@ -451,6 +439,35 @@ static ieee802154_fsm_state_t _fsm_state_wait_for_ack(ieee802154_submac_t *subma
     return IEEE802154_FSM_STATE_INVALID;
 }
 
+static ieee802154_fsm_state_t _fsm_state_tx_ack(ieee802154_submac_t *submac,
+                                                ieee802154_fsm_ev_t ev)
+{
+    ieee802154_tx_info_t info;
+    int res;
+
+    /* This is required to prevent unused variable warnings */
+    (void) res;
+
+    switch (ev) {
+    case IEEE802154_FSM_EV_TX_DONE:
+        if ((res = ieee802154_radio_confirm_transmit(&submac->dev, &info)) >= 0) {
+            return _fsm_state_tx_process_tx_done(submac, &info);
+        }
+        break;
+    case IEEE802154_FSM_EV_CRC_ERROR:
+        /* This might happen in case there's a race condition between ACK_TIMEOUT
+         * and TX_DONE. We simply discard the frame and keep the state as
+         * it is
+         */
+        ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
+        return IEEE802154_FSM_STATE_TX_ACK;
+    default:
+        break;
+    }
+
+    return IEEE802154_FSM_STATE_INVALID;
+}
+
 ieee802154_fsm_state_t ieee802154_submac_process_ev(ieee802154_submac_t *submac,
                                                     ieee802154_fsm_ev_t ev)
 {
@@ -477,6 +494,10 @@ ieee802154_fsm_state_t ieee802154_submac_process_ev(ieee802154_submac_t *submac,
         DEBUG("IEEE802154 submac: ieee802154_submac_process_ev(): IEEE802154_FSM_STATE_WAIT_FOR_ACK + %s\n", str_ev[ev]);
         new_state = _fsm_state_wait_for_ack(submac, ev);
         break;
+    case IEEE802154_FSM_STATE_TX_ACK:
+        DEBUG("IEEE802154 submac: ieee802154_submac_process_ev(): IEEE802154_FSM_STATE_TX_ACK + %s\n", str_ev[ev]);
+        new_state = _fsm_state_tx_ack(submac, ev);
+        break;
     default:
         DEBUG("IEEE802154 submac: ieee802154_submac_process_ev(): INVALID STATE\n");
         new_state = IEEE802154_FSM_STATE_INVALID;
@@ -505,8 +526,6 @@ int ieee802154_send(ieee802154_submac_t *submac, const iolist_t *iolist)
 
     uint8_t *buf = iolist->iol_base;
     bool cnf = buf[0] & IEEE802154_FCF_ACK_REQ;
-    bool is_ack = iolist->iol_len == IEEE802154_ACK_FRAME_LEN - IEEE802154_FCS_LEN &&
-                  (buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_ACK;
 
     submac->wait_for_ack = cnf;
     submac->psdu = iolist;
@@ -514,15 +533,11 @@ int ieee802154_send(ieee802154_submac_t *submac, const iolist_t *iolist)
     submac->csma_retries_nb = 0;
     submac->backoff_mask = (1 << submac->be.min) - 1;
 
-    if (!is_ack && ieee802154_submac_process_ev(submac, IEEE802154_FSM_EV_REQUEST_TX)
+    if (ieee802154_submac_process_ev(submac, IEEE802154_FSM_EV_REQUEST_TX)
         != IEEE802154_FSM_STATE_PREPARE) {
         DEBUG("IEEE802154 submac: ieee802154_send(): Tx frame failed %s\n", str_states[current_state]);
         return -EBUSY;
     }
-    if (is_ack) {
-        DEBUG("IEEE802154 submac: ieee802154_send(): Tx ACK not permitted \n");
-        return -EPERM;
-    }
     return 0;
 }
 

From b3bdb3bf78cd27a197e0a09448a64f0ebed7c523 Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Thu, 22 Jan 2026 10:19:26 +0100
Subject: [PATCH 08/11] fixup! drivers/netdev_ieee802154_submac: remove softack

---
 drivers/netdev_ieee802154_submac/Makefile         | 4 ++++
 drivers/netdev_ieee802154_submac/Makefile.include | 1 +
 makefiles/deprecated_modules.inc.mk               | 1 +
 3 files changed, 6 insertions(+)
 create mode 100644 drivers/netdev_ieee802154_submac/Makefile.include

diff --git a/drivers/netdev_ieee802154_submac/Makefile b/drivers/netdev_ieee802154_submac/Makefile
index 48422e909a47..f4930fec25b2 100644
--- a/drivers/netdev_ieee802154_submac/Makefile
+++ b/drivers/netdev_ieee802154_submac/Makefile
@@ -1 +1,5 @@
+ifneq (,$(filter netdev_ieee802154_submac_soft_ack,$(USEMODULE)))
+  $(warning SubMAC Soft ACK is now on by default and will be deprecated.)
+endif
+
 include $(RIOTBASE)/Makefile.base
diff --git a/drivers/netdev_ieee802154_submac/Makefile.include b/drivers/netdev_ieee802154_submac/Makefile.include
new file mode 100644
index 000000000000..3b3230fef92c
--- /dev/null
+++ b/drivers/netdev_ieee802154_submac/Makefile.include
@@ -0,0 +1 @@
+PSEUDOMODULES += netdev_ieee802154_submac_soft_ack
diff --git a/makefiles/deprecated_modules.inc.mk b/makefiles/deprecated_modules.inc.mk
index 5fe57d31d826..545e0e09234c 100644
--- a/makefiles/deprecated_modules.inc.mk
+++ b/makefiles/deprecated_modules.inc.mk
@@ -2,3 +2,4 @@
 # Keep this list ALPHABETICALLY SORTED!!!!111elven
 DEPRECATED_MODULES += gnrc_nettype_lorawan
 DEPRECATED_MODULES += sema_deprecated
+DEPRECATED_MODULES += netdev_ieee802154_submac_soft_ack

From e0a3316559d26237690d2318452bc6a04866850b Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Thu, 22 Jan 2026 10:20:11 +0100
Subject: [PATCH 09/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/include/net/ieee802154/submac.h    | 60 +++++++++++++++-----------
 sys/net/link_layer/ieee802154/submac.c | 14 +++---
 2 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 7a3a0531c4ec..91737a6e685e 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -30,22 +30,27 @@
  *  |   RX   |        |PREPARE |<--->|   TX   |
  *  |        |   +--->|        |     |        |
  *  +--------+   |    +--------+     +--------+
- *      ^        |        ^              |
- *      |        |        |              |
- *      |        |        |              |
- *      |        |    +--------+         |
- *      |        |    |        |         v
- *      |        |    |WAIT FOR|<--------+
- *      |        |    |  ACK   |         |
- *      |        |    +--------+         |
- *      |        |         |             |
- *      |        |         |             |
- *      |        |         v             |
- *      |        |     +--------+        |
- *      |        +-----|        |        |
- *      |              |  IDLE  |        |
- *      +------------->|        |<-------+
- *                     +--------+
+ *     |  ^      |        ^              |
+ *     |  |      |        |              |
+ *     |  |      |        |              |
+ *     |  |      |    +--------+         |
+ *     |  |      |    |        |         v
+ *     |  |      |    |WAIT FOR|<--------+
+ *     |  |      |    |  ACK   |         |
+ *     |  |      |    +--------+         |
+ *     |  |      |         |             |
+ *     |  |      |         |             |
+ *     |  |      |         v             |
+ *     |  |      |     +--------+        |
+ *     |  |      +-----|        |        |
+ *     |  |            |  IDLE  |        |
+ *     |  +----------->|        |<-------+
+ *     |               +--------+
+ *     |    +--------+     ^
+ *     |    |        |     |
+ *     +--->| TX ACK |-----+
+ *          |        |
+ *          +--------+
  * ```
  *
  * - IDLE: The transceiver is off and therefore cannot receive frames. Sending
@@ -71,22 +76,25 @@
  *   (either triggered by the radio or a timer), the SubMAC goes to either
  *   IDLE if there are no more retransmissions left or no more CSMA-CA
  *   retries or PREPARE otherwise.
+ * - TX ACK: The received frame requires instantanous acknowledgement. Sending
+ *   further frames in this state is not permitted. After ACK transmission is
+ *   completed, the TX DONE event will be handled as usual.
  *
  * The events that trigger state machine changes are defined in
  * @ref ieee802154_fsm_state_t
  *
  * The following events are valid for each state:
  *
- *  Event/State  | RX | IDLE  | PREPARE | TX | WAIT FOR ACK
- * --------------|----|-------|---------|----|-------------
- * TX_DONE       | -  | -     | -       | X  | -
- * RX_DONE       | X  | X*    | X*      | X* | X
- * CRC_ERROR     | X  | X*    | X*      | X* | X
- * ACK_TIMEOUT   | -  | -     | -       | -  | X
- * BH            | -  | -     | X       | -  | -
- * REQ_TX        | X  | X     | -       | -  | -
- * REQ_SET_RX_ON | -  | X     | -       | -  | -
- * REQ_SET_IDLE  | X  | -     | -       | -  | -
+ *  Event/State  | RX | IDLE  | PREPARE | TX | WAIT FOR ACK | TX ACK |
+ * --------------|----|-------|---------|----|------------------------
+ * TX_DONE       | -  | -     | -       | X  | -            |X
+ * RX_DONE       | X  | X*    | X*      | X* | X            |-
+ * CRC_ERROR     | X  | X*    | X*      | X* | X            |-
+ * ACK_TIMEOUT   | -  | -     | -       | -  | X            |-
+ * BH            | -  | -     | X       | -  | -            |-
+ * REQ_TX        | X  | X     | -       | -  | -            |-
+ * REQ_SET_RX_ON | -  | X     | -       | -  | -            |-
+ * REQ_SET_IDLE  | X  | -     | -       | -  | -            |-
  *
  * *: RX_DONE and CRC_ERROR during these events might be a race condition
  *    between the ACK Timer and the radios RX_DONE event. If this happens, the
diff --git a/sys/net/link_layer/ieee802154/submac.c b/sys/net/link_layer/ieee802154/submac.c
index f7b27f410f25..aa28af486e7b 100644
--- a/sys/net/link_layer/ieee802154/submac.c
+++ b/sys/net/link_layer/ieee802154/submac.c
@@ -97,7 +97,10 @@ static ieee802154_fsm_state_t _tx_end(ieee802154_submac_t *submac, int status,
     res = ieee802154_radio_set_idle(&submac->dev, true);
 
     assert(res >= 0);
-    submac->cb->tx_done(submac, status, info);
+    /* no need to inform upper layer about ACK transmission */
+    if (submac->fsm_state != IEEE802154_FSM_STATE_TX_ACK) {
+        submac->cb->tx_done(submac, status, info);
+    }
     return IEEE802154_FSM_STATE_IDLE;
 }
 
@@ -196,6 +199,7 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
         assert(res == (int)submac->rx_len);
         /* Make sure it's not an ACK frame */
         if (ieee802154_radio_len(dev) > (int)IEEE802154_MIN_FRAME_LEN) {
+            /* sending ACK if radio does not support auto-ACK */
             if (!_does_send_ack(dev)) {
                 ieee802154_filter_mode_t mode;
                 if ((submac->rx_buf[0] & IEEE802154_FCF_TYPE_MASK) == IEEE802154_FCF_TYPE_DATA &&
@@ -205,6 +209,7 @@ static ieee802154_fsm_state_t _fsm_state_rx(ieee802154_submac_t *submac, ieee802
                         res = _handle_fsm_ev_tx_ack(submac, ieee802154_get_seq(submac->rx_buf));
                         submac->cb->rx_done(submac);
                         if (res < 0) {
+                            DEBUG("IEEE802154 submac: Sending ACK failed with status: %d\n", res);
                             return IEEE802154_FSM_STATE_IDLE;
                         }
                         return IEEE802154_FSM_STATE_TX_ACK;
@@ -454,13 +459,6 @@ static ieee802154_fsm_state_t _fsm_state_tx_ack(ieee802154_submac_t *submac,
             return _fsm_state_tx_process_tx_done(submac, &info);
         }
         break;
-    case IEEE802154_FSM_EV_CRC_ERROR:
-        /* This might happen in case there's a race condition between ACK_TIMEOUT
-         * and TX_DONE. We simply discard the frame and keep the state as
-         * it is
-         */
-        ieee802154_radio_read(&submac->dev, NULL, 0, NULL);
-        return IEEE802154_FSM_STATE_TX_ACK;
     default:
         break;
     }

From 8c6dc3425d3ca026d28f46706df5aecddae80479 Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Thu, 22 Jan 2026 12:40:30 +0100
Subject: [PATCH 10/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/include/net/ieee802154/submac.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 91737a6e685e..4cc9150db3ca 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -57,8 +57,9 @@
  *   frames might be triggered using @ref ieee802154_send. The next SubMAC
  *   state would be PREPARE.
  * - RX: The device is ready to receive frames. In case the SubMAC receives a
- *   frame it will call @ref ieee802154_submac_cb_t::rx_done and immediately go
- *   to IDLE. Same as the IDLE state, it's possible
+ *   frame it will transmit an ACK frame if necessary then call
+ *   @ref ieee802154_submac_cb_t::rx_done and immediately go
+ *   to IDLE or TX ACK. Same as the IDLE state, it's possible
  *   to trigger frames using @ref ieee802154_send.
  * - PREPARE: The frame is already in the framebuffer and waiting to be
  *   transmitted.  This state might handle CSMA-CA backoff timer in case the

From 22683b3257a2cfb8591e6a30c38a481d04b1bb32 Mon Sep 17 00:00:00 2001
From: Lukas-Luger <lukas.luger@mailbox.tu-dresden.de>
Date: Thu, 22 Jan 2026 12:42:13 +0100
Subject: [PATCH 11/11] fixup! sys/net/link_layer/ieee802154/submac: add tx ack
 logic

---
 sys/include/net/ieee802154/submac.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/include/net/ieee802154/submac.h b/sys/include/net/ieee802154/submac.h
index 4cc9150db3ca..eebf58b65457 100644
--- a/sys/include/net/ieee802154/submac.h
+++ b/sys/include/net/ieee802154/submac.h
@@ -79,7 +79,7 @@
  *   retries or PREPARE otherwise.
  * - TX ACK: The received frame requires instantanous acknowledgement. Sending
  *   further frames in this state is not permitted. After ACK transmission is
- *   completed, the TX DONE event will be handled as usual.
+ *   completed, the SubMAC will go IDLE.
  *
  * The events that trigger state machine changes are defined in
  * @ref ieee802154_fsm_state_t