diff --git a/lib/include/srslte/interfaces/enb_interfaces.h b/lib/include/srslte/interfaces/enb_interfaces.h
index 84d96cf01..1b614713b 100644
--- a/lib/include/srslte/interfaces/enb_interfaces.h
+++ b/lib/include/srslte/interfaces/enb_interfaces.h
@@ -160,6 +160,9 @@ public:
   /**
    * Informs MAC about a received PUSCH transmission for given RNTI, TTI and eNb Cell/carrier.
    *
+   * This function does not deallocate the uplink buffer. The function push_pdu() must be called after this
+   * to inform the MAC that the uplink buffer can be discarded or pushed to the stack
+   *
    * @param tti the given TTI
    * @param rnti the UE identifier in the eNb
    * @param cc_idx the eNb Cell/Carrier identifier
@@ -169,6 +172,18 @@ public:
    */
   virtual int crc_info(uint32_t tti, uint16_t rnti, uint32_t cc_idx, uint32_t nof_bytes, bool crc_res) = 0;
 
+  /**
+   * Pushes an uplink PDU through the stack if crc_res==true or discards it if crc_res==false
+   *
+   * @param tti the given TTI
+   * @param rnti the UE identifier in the eNb
+   * @param pdu_ptr pointer to the uplink buffer
+   * @param nof_bytes the number of grants carrierd by the PUSCH message
+   * @param crc_res the CRC check, set to true if the message was decoded succesfully
+   * @return SRSLTE_SUCCESS if no error occurs, SRSLTE_ERROR* if an error occurs
+   */
+  virtual int push_pdu(uint32_t tti_rx, uint16_t rnti, const uint8_t* pdu_ptr, uint32_t nof_bytes, bool crc_res) = 0;
+
   virtual int  get_dl_sched(uint32_t tti, dl_sched_list_t& dl_sched_res)                = 0;
   virtual int  get_mch_sched(uint32_t tti, bool is_mcch, dl_sched_list_t& dl_sched_res) = 0;
   virtual int  get_ul_sched(uint32_t tti, ul_sched_list_t& ul_sched_res)                = 0;
diff --git a/lib/include/srslte/mac/pdu_queue.h b/lib/include/srslte/mac/pdu_queue.h
index 89c9bfa39..0bf94f9ae 100644
--- a/lib/include/srslte/mac/pdu_queue.h
+++ b/lib/include/srslte/mac/pdu_queue.h
@@ -37,8 +37,8 @@ public:
   void init(process_callback* callback, log_ref log_h_);
 
   uint8_t* request(uint32_t len);
-  void     deallocate(uint8_t* pdu);
-  void     push(uint8_t* ptr, uint32_t len, channel_t channel = DCH);
+  void     deallocate(const uint8_t* pdu);
+  void     push(const uint8_t* ptr, uint32_t len, channel_t channel = DCH);
 
   bool process_pdus();
 
diff --git a/lib/src/mac/pdu_queue.cc b/lib/src/mac/pdu_queue.cc
index 6d90ceed7..bd8628b0e 100644
--- a/lib/src/mac/pdu_queue.cc
+++ b/lib/src/mac/pdu_queue.cc
@@ -42,7 +42,7 @@ uint8_t* pdu_queue::request(uint32_t len)
   return pdu->ptr;
 }
 
-void pdu_queue::deallocate(uint8_t* pdu)
+void pdu_queue::deallocate(const uint8_t* pdu)
 {
   if (!pool.deallocate((pdu_t*)pdu)) {
     log_h->warning("Error deallocating from buffer pool in deallocate(): buffer not created in this pool.\n");
@@ -53,7 +53,7 @@ void pdu_queue::deallocate(uint8_t* pdu)
  * This function enqueues the packet and returns quicly because ACK
  * deadline is important here.
  */
-void pdu_queue::push(uint8_t* ptr, uint32_t len, channel_t channel)
+void pdu_queue::push(const uint8_t* ptr, uint32_t len, channel_t channel)
 {
   if (ptr) {
     pdu_t* pdu   = (pdu_t*)ptr;
diff --git a/srsenb/hdr/stack/enb_stack_lte.h b/srsenb/hdr/stack/enb_stack_lte.h
index 719b835b7..cd0c88cf6 100644
--- a/srsenb/hdr/stack/enb_stack_lte.h
+++ b/srsenb/hdr/stack/enb_stack_lte.h
@@ -81,6 +81,10 @@ public:
   {
     return mac.crc_info(tti, rnti, enb_cc_idx, nof_bytes, crc_res);
   }
+  int push_pdu(uint32_t tti, uint16_t rnti, const uint8_t* pdu_ptr, uint32_t nof_bytes, bool crc_res) final
+  {
+    return mac.push_pdu(tti, rnti, pdu_ptr, nof_bytes, crc_res);
+  }
   int get_dl_sched(uint32_t tti, dl_sched_list_t& dl_sched_res) final { return mac.get_dl_sched(tti, dl_sched_res); }
   int get_mch_sched(uint32_t tti, bool is_mcch, dl_sched_list_t& dl_sched_res) final
   {
diff --git a/srsenb/hdr/stack/mac/mac.h b/srsenb/hdr/stack/mac/mac.h
index e3e4beaf1..06b4b4619 100644
--- a/srsenb/hdr/stack/mac/mac.h
+++ b/srsenb/hdr/stack/mac/mac.h
@@ -56,6 +56,7 @@ public:
   int ta_info(uint32_t tti, uint16_t rnti, float ta_us) override;
   int ack_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t tb_idx, bool ack) override;
   int crc_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t nof_bytes, bool crc_res) override;
+  int push_pdu(uint32_t tti, uint16_t rnti, const uint8_t* pdu_ptr, uint32_t nof_bytes, bool crc_res) override;
 
   int  get_dl_sched(uint32_t tti_tx_dl, dl_sched_list_t& dl_sched_res) override;
   int  get_ul_sched(uint32_t tti_tx_ul, ul_sched_list_t& ul_sched_res) override;
diff --git a/srsenb/hdr/stack/mac/ue.h b/srsenb/hdr/stack/mac/ue.h
index 7127c088b..f8e9b7b9f 100644
--- a/srsenb/hdr/stack/mac/ue.h
+++ b/srsenb/hdr/stack/mac/ue.h
@@ -71,10 +71,10 @@ public:
   srslte_softbuffer_rx_t* get_rx_softbuffer(const uint32_t ue_cc_idx, const uint32_t tti);
 
   bool     process_pdus();
-  uint8_t* request_buffer(const uint32_t ue_cc_idx, const uint32_t tti, const uint32_t len);
+  uint8_t* request_buffer(const uint32_t len);
   void     process_pdu(uint8_t* pdu, uint32_t nof_bytes, srslte::pdu_queue::channel_t channel) override;
-  void     push_pdu(const uint32_t ue_cc_idx, const uint32_t tti, uint32_t len);
-  void     deallocate_pdu(const uint32_t ue_cc_idx, const uint32_t tti);
+  void     push_pdu(const uint8_t* pdu_ptr, uint32_t len);
+  void     deallocate_pdu(const uint8_t* pdu_ptr);
 
   void metrics_read(mac_ue_metrics_t* metrics_);
   void metrics_rx(bool crc, uint32_t tbs);
@@ -118,9 +118,6 @@ private:
                                        cc_softbuffer_rx_list_t; ///< List of Rx softbuffers for all HARQ processes of one carrier
   std::vector<cc_softbuffer_rx_list_t> softbuffer_rx;           ///< List of softbuffer lists for Rx
 
-  typedef std::vector<uint8_t*> cc_buffer_ptr_t; ///< List of buffer pointers for RX HARQ processes of one carrier
-  std::vector<cc_buffer_ptr_t>  pending_buffers; ///< List of buffer pointer list for Rx
-
   // One buffer per TB per HARQ process and per carrier is needed for each UE.
   std::vector<std::array<std::array<srslte::unique_byte_buffer_t, SRSLTE_MAX_TB>, SRSLTE_FDD_NOF_HARQ> >
       tx_payload_buffer;
diff --git a/srsenb/src/phy/lte/cc_worker.cc b/srsenb/src/phy/lte/cc_worker.cc
index b72197248..0c568d39b 100644
--- a/srsenb/src/phy/lte/cc_worker.cc
+++ b/srsenb/src/phy/lte/cc_worker.cc
@@ -373,7 +373,8 @@ void cc_worker::decode_pusch(stack_interface_phy_lte::ul_sched_grant_t* grants,
     if (ul_grant.data != nullptr) {
       // Inform MAC about the CRC result
       phy->stack->crc_info(tti_rx, rnti, cc_idx, ul_cfg.pusch.grant.tb.tbs / 8, pusch_res.crc);
-
+      // Push PDU buffer
+      phy->stack->push_pdu(tti_rx, rnti, grants[i].data, ul_cfg.pusch.grant.tb.tbs / 8, pusch_res.crc);
       // Logging
       if (log_h->get_level() >= srslte::LOG_LEVEL_INFO) {
         char str[512];
diff --git a/srsenb/src/stack/mac/mac.cc b/srsenb/src/stack/mac/mac.cc
index 0d6d9fb98..d7ce68e09 100644
--- a/srsenb/src/stack/mac/mac.cc
+++ b/srsenb/src/stack/mac/mac.cc
@@ -320,24 +320,28 @@ int mac::crc_info(uint32_t tti_rx, uint16_t rnti, uint32_t enb_cc_idx, uint32_t
   ue_db[rnti]->set_tti(tti_rx);
   ue_db[rnti]->metrics_rx(crc, nof_bytes);
 
-  std::array<int, SRSLTE_MAX_CARRIERS> enb_ue_cc_map = scheduler.get_enb_ue_cc_map(rnti);
-  if (enb_ue_cc_map[enb_cc_idx] < 0) {
-    Error("User rnti=0x%x is not activated for carrier %d\n", rnti, enb_cc_idx);
+  // Scheduler uses eNB's CC mapping
+  return scheduler.ul_crc_info(tti_rx, rnti, enb_cc_idx, crc);
+}
+
+int mac::push_pdu(uint32_t tti_rx, uint16_t rnti, const uint8_t* pdu_ptr, uint32_t nof_bytes, bool crc)
+{
+  srslte::rwlock_read_guard lock(rwlock);
+
+  if (not check_ue_exists(rnti)) {
     return SRSLTE_ERROR;
   }
-  uint32_t ue_cc_idx = enb_ue_cc_map[enb_cc_idx];
 
   // push the pdu through the queue if received correctly
   if (crc) {
     Info("Pushing PDU rnti=0x%x, tti_rx=%d, nof_bytes=%d\n", rnti, tti_rx, nof_bytes);
-    ue_db[rnti]->push_pdu(ue_cc_idx, tti_rx, nof_bytes);
+    ue_db[rnti]->push_pdu(pdu_ptr, nof_bytes);
     stack_task_queue.push([this]() { process_pdus(); });
   } else {
-    ue_db[rnti]->deallocate_pdu(ue_cc_idx, tti_rx);
+    Debug("Discarting PDU rnti=0x%x, tti_rx=%d, nof_bytes=%d\n", rnti, tti_rx, nof_bytes);
+    ue_db[rnti]->deallocate_pdu(pdu_ptr);
   }
-
-  // Scheduler uses eNB's CC mapping
-  return scheduler.ul_crc_info(tti_rx, rnti, enb_cc_idx, crc);
+  return SRSLTE_SUCCESS;
 }
 
 int mac::ri_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t ri_value)
@@ -894,8 +898,7 @@ int mac::get_ul_sched(uint32_t tti_tx_ul, ul_sched_list_t& ul_sched_res_list)
             if (sched_result.pusch[n].current_tx_nb == 0) {
               srslte_softbuffer_rx_reset_tbs(phy_ul_sched_res->pusch[n].softbuffer_rx, sched_result.pusch[i].tbs * 8);
             }
-            phy_ul_sched_res->pusch[n].data =
-                ue_db[rnti]->request_buffer(sched_result.pusch[i].dci.ue_cc_idx, tti_tx_ul, sched_result.pusch[i].tbs);
+            phy_ul_sched_res->pusch[n].data = ue_db[rnti]->request_buffer(sched_result.pusch[i].tbs);
             phy_ul_sched_res->nof_grants++;
             n++;
           } else {
diff --git a/srsenb/src/stack/mac/ue.cc b/srsenb/src/stack/mac/ue.cc
index 44ae26200..d0e99c2a9 100644
--- a/srsenb/src/stack/mac/ue.cc
+++ b/srsenb/src/stack/mac/ue.cc
@@ -94,15 +94,6 @@ void ue::reset()
       srslte_softbuffer_tx_reset(&buffer);
     }
   }
-
-  for (auto& cc_buffers : pending_buffers) {
-    for (auto& harq_buffer : cc_buffers) {
-      if (harq_buffer) {
-        pdus.deallocate(harq_buffer);
-        harq_buffer = nullptr;
-      }
-    }
-  }
 }
 
 /**
@@ -123,12 +114,6 @@ uint32_t ue::allocate_cc_buffers(const uint32_t num_cc)
       srslte_softbuffer_rx_init(&buffer, nof_prb);
     }
 
-    pending_buffers.emplace_back();
-    pending_buffers.back().resize(nof_rx_harq_proc);
-    for (auto& buffer : pending_buffers.back()) {
-      buffer = nullptr;
-    }
-
     // Create and init Tx buffers for Pcell
     softbuffer_tx.emplace_back();
     softbuffer_tx.back().resize(nof_tx_harq_proc);
@@ -176,20 +161,14 @@ ue::get_tx_softbuffer(const uint32_t ue_cc_idx, const uint32_t harq_process, con
   return &softbuffer_tx.at(ue_cc_idx).at((harq_process * SRSLTE_MAX_TB + tb_idx) % nof_tx_harq_proc);
 }
 
-uint8_t* ue::request_buffer(const uint32_t ue_cc_idx, const uint32_t tti, const uint32_t len)
+uint8_t* ue::request_buffer(const uint32_t len)
 {
-  uint8_t* ret = nullptr;
   if (len > 0) {
-    if (!pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc)) {
-      ret                                                      = pdus.request(len);
-      pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc) = ret;
-    } else {
-      log_h->error("Requesting buffer for pid %d, not pushed yet\n", tti % nof_rx_harq_proc);
-    }
+    return pdus.request(len);
   } else {
     log_h->warning("Requesting buffer for zero bytes\n");
+    return nullptr;
   }
-  return ret;
 }
 
 bool ue::process_pdus()
@@ -314,25 +293,21 @@ void ue::process_pdu(uint8_t* pdu, uint32_t nof_bytes, srslte::pdu_queue::channe
   Debug("MAC PDU processed\n");
 }
 
-void ue::deallocate_pdu(const uint32_t ue_cc_idx, const uint32_t tti)
+void ue::deallocate_pdu(const uint8_t* pdu_ptr)
 {
-  if (pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc)) {
-    pdus.deallocate(pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc));
-    pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc) = nullptr;
+  if (pdu_ptr) {
+    pdus.deallocate(pdu_ptr);
   } else {
-    srslte::console(
-        "Error deallocating buffer for ue_cc_idx=%d, pid=%d. Not requested\n", ue_cc_idx, tti % nof_rx_harq_proc);
+    Error("Error deallocating PDU: null ptr\n");
   }
 }
 
-void ue::push_pdu(const uint32_t ue_cc_idx, const uint32_t tti, uint32_t len)
+void ue::push_pdu(const uint8_t* pdu_ptr, uint32_t len)
 {
-  if (pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc)) {
-    pdus.push(pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc), len);
-    pending_buffers.at(ue_cc_idx).at(tti % nof_rx_harq_proc) = nullptr;
+  if (pdu_ptr && len > 0) {
+    pdus.push(pdu_ptr, len);
   } else {
-    srslte::console(
-        "Error pushing buffer for ue_cc_idx=%d, pid=%d. Not requested\n", ue_cc_idx, tti % nof_rx_harq_proc);
+    Error("Error pushing PDU: ptr=%p, len=%d\n", pdu_ptr, len);
   }
 }
 
diff --git a/srsenb/test/phy/enb_phy_test.cc b/srsenb/test/phy/enb_phy_test.cc
index 402102c9c..eee341fe8 100644
--- a/srsenb/test/phy/enb_phy_test.cc
+++ b/srsenb/test/phy/enb_phy_test.cc
@@ -289,6 +289,7 @@ private:
   CALLBACK(ta_info);
   CALLBACK(ack_info);
   CALLBACK(crc_info);
+  CALLBACK(push_pdu);
   CALLBACK(get_dl_sched);
   CALLBACK(get_mch_sched);
   CALLBACK(get_ul_sched);
@@ -492,6 +493,13 @@ public:
 
     return 0;
   }
+  int push_pdu(uint32_t tti, uint16_t rnti, const uint8_t* pdu_ptr, uint32_t nof_bytes, bool crc_res) override
+  {
+    log_h.info("Received push_pdu tti=%d; rnti=0x%x; ack=%d;\n", tti, rnti, crc_res);
+    notify_push_pdu();
+
+    return 0;
+  }
   int get_dl_sched(uint32_t tti, dl_sched_list_t& dl_sched_res) override
   {
     // Notify test engine