diff --git a/srsenb/hdr/stack/mac/mac.h b/srsenb/hdr/stack/mac/mac.h
index 796b6aa24..994352fe9 100644
--- a/srsenb/hdr/stack/mac/mac.h
+++ b/srsenb/hdr/stack/mac/mac.h
@@ -130,8 +130,8 @@ private:
   sched_interface::dl_pdu_mch_t mch = {};
 
   /* Map of active UEs */
-  std::map<uint16_t, ue*> ue_db;
-  uint16_t                last_rnti = 0;
+  std::map<uint16_t, std::unique_ptr<ue> > ue_db;
+  uint16_t                                 last_rnti = 0;
 
   uint8_t* assemble_rar(sched_interface::dl_sched_rar_grant_t* grants,
                         uint32_t                               nof_grants,
diff --git a/srsenb/hdr/stack/mac/ue.h b/srsenb/hdr/stack/mac/ue.h
index f91087bd3..7074313bb 100644
--- a/srsenb/hdr/stack/mac/ue.h
+++ b/srsenb/hdr/stack/mac/ue.h
@@ -46,6 +46,7 @@ public:
      rlc_interface_mac*       rlc,
      phy_interface_stack_lte* phy_,
      srslte::log_ref          log_,
+     uint32_t                 nof_cells_,
      uint32_t                 nof_rx_harq_proc = SRSLTE_FDD_NOF_HARQ,
      uint32_t                 nof_tx_harq_proc = SRSLTE_FDD_NOF_HARQ * SRSLTE_MAX_TB);
   virtual ~ue();
@@ -101,7 +102,7 @@ public:
   void metrics_cnt();
 
   bool is_phy_added = false;
-  int  read_pdu(uint32_t lcid, uint8_t* payload, uint32_t requested_bytes);
+  int  read_pdu(uint32_t lcid, uint8_t* payload, uint32_t requested_bytes) final;
 
 private:
   uint32_t allocate_cc_buffers(const uint32_t num_cc = 1); ///< Add and initialize softbuffers for CC
@@ -138,9 +139,8 @@ private:
   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
 
-  // For DL there are two buffers, one for each Transport block
-  std::array<std::array<std::array<srslte::unique_byte_buffer_t, SRSLTE_MAX_TB>, SRSLTE_FDD_NOF_HARQ>,
-             SRSLTE_MAX_CARRIERS>
+  // 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;
 
   srslte::block_queue<uint32_t> pending_ta_commands;
diff --git a/srsenb/src/stack/mac/mac.cc b/srsenb/src/stack/mac/mac.cc
index e038a7fa3..9110fccea 100644
--- a/srsenb/src/stack/mac/mac.cc
+++ b/srsenb/src/stack/mac/mac.cc
@@ -100,9 +100,7 @@ void mac::stop()
 {
   srslte::rwlock_write_guard lock(rwlock);
   if (started) {
-    for (uint32_t i = 0; i < ue_db.size(); i++) {
-      delete ue_db[i];
-    }
+    ue_db.clear();
     for (int i = 0; i < NOF_BCCH_DLSCH_MSG; i++) {
       srslte_softbuffer_tx_free(&bcch_softbuffer_tx[i]);
     }
@@ -200,7 +198,7 @@ int mac::ue_cfg(uint16_t rnti, sched_interface::ue_cfg_t* cfg)
     Error("User rnti=0x%x not found\n", rnti);
     return SRSLTE_ERROR;
   }
-  ue_ptr = it->second;
+  ue_ptr = it->second.get();
 
   // Add RNTI to the PHY (pregenerate signals) now instead of after PRACH
   if (not ue_ptr->is_phy_added) {
@@ -240,7 +238,6 @@ int mac::ue_rem(uint16_t rnti)
   }
   srslte::rwlock_write_guard lock(rwlock);
   if (ue_db.count(rnti)) {
-    delete ue_db[rnti];
     ue_db.erase(rnti);
     Info("User rnti=0x%x removed from MAC/PHY\n", rnti);
   } else {
@@ -457,7 +454,8 @@ void mac::rach_detected(uint32_t tti, uint32_t enb_cc_idx, uint32_t preamble_idx
 
     // Create new UE
     if (ue_db.count(rnti) == 0) {
-      ue_db[rnti] = new ue(rnti, args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, log_h, SRSLTE_FDD_NOF_HARQ);
+      ue_db[rnti] =
+          std::unique_ptr<ue>{new ue(rnti, args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, log_h, cells.size())};
     }
 
     // Set PCAP if available
@@ -884,7 +882,8 @@ void mac::write_mcch(sib_type2_s* sib2_, sib_type13_r9_s* sib13_, mcch_msg_s* mc
   mcch.pack(bref);
   current_mcch_length = bref.distance_bytes(&mcch_payload_buffer[1]);
   current_mcch_length = current_mcch_length + rlc_header_len;
-  ue_db[SRSLTE_MRNTI] = new ue(SRSLTE_MRNTI, args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, log_h);
+  ue_db[SRSLTE_MRNTI] =
+      std::unique_ptr<ue>{new ue(SRSLTE_MRNTI, args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, log_h, cells.size())};
 
   rrc_h->add_user(SRSLTE_MRNTI, {});
 }
diff --git a/srsenb/src/stack/mac/ue.cc b/srsenb/src/stack/mac/ue.cc
index 3acad9cfd..b11998ba6 100644
--- a/srsenb/src/stack/mac/ue.cc
+++ b/srsenb/src/stack/mac/ue.cc
@@ -41,6 +41,7 @@ ue::ue(uint16_t                 rnti_,
        rlc_interface_mac*       rlc_,
        phy_interface_stack_lte* phy_,
        srslte::log_ref          log_,
+       uint32_t                 nof_cells_,
        uint32_t                 nof_rx_harq_proc_,
        uint32_t                 nof_tx_harq_proc_) :
   rnti(rnti_),
@@ -59,6 +60,7 @@ ue::ue(uint16_t                 rnti_,
   ta_fsm(this)
 {
   srslte::byte_buffer_pool* pool = srslte::byte_buffer_pool::get_instance();
+  tx_payload_buffer.resize(nof_cells_);
   for (auto& carrier_buffers : tx_payload_buffer) {
     for (auto& harq_buffers : carrier_buffers) {
       for (srslte::unique_byte_buffer_t& tb_buffer : harq_buffers) {