diff --git a/lib/include/srsran/interfaces/gnb_interfaces.h b/lib/include/srsran/interfaces/gnb_interfaces.h
index aad2b4072..9de1488a2 100644
--- a/lib/include/srsran/interfaces/gnb_interfaces.h
+++ b/lib/include/srsran/interfaces/gnb_interfaces.h
@@ -223,8 +223,8 @@ public:
   };
 
   struct pdsch_t {
-    srsran_sch_cfg_nr_t                 sch  = {}; ///< PDSCH configuration
-    std::array<uint8_t*, SRSRAN_MAX_TB> data = {}; ///< Data pointer
+    srsran_sch_cfg_nr_t                               sch  = {}; ///< PDSCH configuration
+    std::array<srsran::byte_buffer_t*, SRSRAN_MAX_TB> data = {}; ///< Data pointer
   };
 
   struct ssb_t {
diff --git a/srsenb/hdr/stack/mac/nr/sched_nr_harq.h b/srsenb/hdr/stack/mac/nr/sched_nr_harq.h
index 22c21f1f8..0689bd24d 100644
--- a/srsenb/hdr/stack/mac/nr/sched_nr_harq.h
+++ b/srsenb/hdr/stack/mac/nr/sched_nr_harq.h
@@ -85,11 +85,13 @@ public:
   dl_harq_proc(uint32_t id_, uint32_t nprb);
 
   tx_harq_softbuffer& get_softbuffer() { return *softbuffer; }
-  uint8_t*            get_tx_pdu() { return pdu->msg; }
+  srsran::unique_byte_buffer_t* get_tx_pdu() { return &pdu; }
 
+  // clear and reset softbuffer and PDU for new tx
   bool set_tbs(uint32_t tbs)
   {
     softbuffer->reset();
+    pdu->clear();
     return harq_proc::set_tbs(tbs);
   }
 
diff --git a/srsenb/hdr/stack/mac/nr/ue_nr.h b/srsenb/hdr/stack/mac/nr/ue_nr.h
index 355d9a6ed..0e644cb9e 100644
--- a/srsenb/hdr/stack/mac/nr/ue_nr.h
+++ b/srsenb/hdr/stack/mac/nr/ue_nr.h
@@ -48,13 +48,8 @@ public:
   void     set_active(bool active) { active_state.store(active, std::memory_order_relaxed); }
   bool     is_active() const { return active_state.load(std::memory_order_relaxed); }
 
-  uint8_t* generate_pdu(uint32_t                              enb_cc_idx,
-                        uint32_t                              harq_pid,
-                        uint32_t                              tb_idx,
-                        const sched_interface::dl_sched_pdu_t pdu[sched_interface::MAX_RLC_PDU_LIST],
-                        uint32_t                              nof_pdu_elems,
-                        uint32_t                              grant_size);
-  int      process_pdu(srsran::unique_byte_buffer_t pdu);
+  int generate_pdu(srsran::byte_buffer_t* pdu, uint32_t grant_size);
+  int process_pdu(srsran::unique_byte_buffer_t pdu);
 
   std::mutex metrics_mutex = {};
   void       metrics_read(mac_ue_metrics_t* metrics_);
diff --git a/srsenb/src/phy/nr/slot_worker.cc b/srsenb/src/phy/nr/slot_worker.cc
index 1b92dc3f4..138659e94 100644
--- a/srsenb/src/phy/nr/slot_worker.cc
+++ b/srsenb/src/phy/nr/slot_worker.cc
@@ -295,8 +295,16 @@ bool slot_worker::work_dl()
 
   // Encode PDSCH
   for (stack_interface_phy_nr::pdsch_t& pdsch : dl_sched.pdsch) {
+    // convert MAC to PHY buffer data structures
+    uint8_t* data[SRSRAN_MAX_TB] = {};
+    for (uint32_t i = 0; i < SRSRAN_MAX_TB; ++i) {
+      if (pdsch.data[i] != nullptr) {
+        data[i] = pdsch.data[i]->msg;
+      }
+    }
+
     // Put PDSCH message
-    if (srsran_gnb_dl_pdsch_put(&gnb_dl, &dl_slot_cfg, &pdsch.sch, pdsch.data.data()) < SRSRAN_SUCCESS) {
+    if (srsran_gnb_dl_pdsch_put(&gnb_dl, &dl_slot_cfg, &pdsch.sch, data) < SRSRAN_SUCCESS) {
       logger.error("PDSCH: Error putting DL message");
       return false;
     }
diff --git a/srsenb/src/stack/mac/nr/mac_nr.cc b/srsenb/src/stack/mac/nr/mac_nr.cc
index b6c270f4f..843f63250 100644
--- a/srsenb/src/stack/mac/nr/mac_nr.cc
+++ b/srsenb/src/stack/mac/nr/mac_nr.cc
@@ -272,7 +272,21 @@ int mac_nr::get_dl_sched(const srsran_slot_cfg_t& slot_cfg, dl_sched_t& dl_sched
     pdsch_slot++;
   }
 
-  return sched.get_dl_sched(pdsch_slot, 0, dl_sched);
+  int ret = sched.get_dl_sched(pdsch_slot, 0, dl_sched);
+  for (pdsch_t& pdsch : dl_sched.pdsch) {
+    for (auto& tb_data : pdsch.data) {
+      if (tb_data != nullptr) {
+        // TODO: exclude retx from packing
+        uint16_t                  rnti = pdsch.sch.grant.rnti;
+        srsran::rwlock_read_guard rw_lock(rwlock);
+        if (not is_rnti_active_unsafe(rnti)) {
+          continue;
+        }
+        ue_db[rnti]->generate_pdu(tb_data, pdsch.sch.grant.tb->tbs / 8);
+      }
+    }
+  }
+  return SRSRAN_SUCCESS;
 }
 
 int mac_nr::get_ul_sched(const srsran_slot_cfg_t& slot_cfg, ul_sched_t& ul_sched)
diff --git a/srsenb/src/stack/mac/nr/sched_nr_rb_grid.cc b/srsenb/src/stack/mac/nr/sched_nr_rb_grid.cc
index 7080cbf0d..1eb31ae58 100644
--- a/srsenb/src/stack/mac/nr/sched_nr_rb_grid.cc
+++ b/srsenb/src/stack/mac/nr/sched_nr_rb_grid.cc
@@ -230,7 +230,7 @@ alloc_result bwp_slot_allocator::alloc_pdsch(slot_ue& ue, const prb_grant& dl_gr
   bool ret     = ue.cfg->phy().get_pdsch_cfg(slot_cfg, pdcch.dci, pdsch.sch);
   srsran_assert(ret, "Error converting DCI to grant");
   pdsch.sch.grant.tb[0].softbuffer.tx = ue.h_dl->get_softbuffer().get();
-  pdsch.data[0]                       = ue.h_dl->get_tx_pdu();
+  pdsch.data[0]                       = ue.h_dl->get_tx_pdu()->get();
   if (ue.h_dl->nof_retx() == 0) {
     ue.h_dl->set_tbs(pdsch.sch.grant.tb[0].tbs); // update HARQ with correct TBS
   } else {
diff --git a/srsenb/src/stack/mac/nr/ue_nr.cc b/srsenb/src/stack/mac/nr/ue_nr.cc
index 42ff4710e..e2d8f5108 100644
--- a/srsenb/src/stack/mac/nr/ue_nr.cc
+++ b/srsenb/src/stack/mac/nr/ue_nr.cc
@@ -16,6 +16,7 @@
 #include <string.h>
 
 #include "srsenb/hdr/stack/mac/nr/ue_nr.h"
+#include "srsran/common/buffer_pool.h"
 #include "srsran/common/string_helpers.h"
 #include "srsran/interfaces/gnb_interfaces.h"
 
@@ -28,7 +29,13 @@ ue_nr::ue_nr(uint16_t                rnti_,
              rlc_interface_mac*      rlc_,
              phy_interface_stack_nr* phy_,
              srslog::basic_logger&   logger_) :
-  rnti(rnti_), sched(sched_), rrc(rrc_), rlc(rlc_), phy(phy_), logger(logger_)
+  rnti(rnti_),
+  sched(sched_),
+  rrc(rrc_),
+  rlc(rlc_),
+  phy(phy_),
+  logger(logger_),
+  ue_rlc_buffer(srsran::make_byte_buffer())
 {}
 
 ue_nr::~ue_nr() {}
@@ -82,47 +89,35 @@ uint32_t ue_nr::read_pdu(uint32_t lcid, uint8_t* payload, uint32_t requested_byt
   return rlc->read_pdu(rnti, lcid, payload, requested_bytes);
 }
 
-uint8_t* ue_nr::generate_pdu(uint32_t                              enb_cc_idx,
-                             uint32_t                              harq_pid,
-                             uint32_t                              tb_idx,
-                             const sched_interface::dl_sched_pdu_t pdu[sched_interface::MAX_RLC_PDU_LIST],
-                             uint32_t                              nof_pdu_elems,
-                             uint32_t                              grant_size)
+int ue_nr::generate_pdu(srsran::byte_buffer_t* pdu, uint32_t grant_size)
 {
   std::lock_guard<std::mutex> lock(mutex);
-  uint8_t*                    ret = nullptr;
-  if (enb_cc_idx < SRSRAN_MAX_CARRIERS && harq_pid < SRSRAN_FDD_NOF_HARQ && tb_idx < SRSRAN_MAX_TB) {
-    srsran::byte_buffer_t* buffer = nullptr; // TODO: read from scheduler output
-    buffer->clear();
-
-    mac_pdu_dl.init_tx(buffer, grant_size);
-
-    // read RLC PDU
-    ue_rlc_buffer->clear();
-    int lcid    = 4;
-    int pdu_len = rlc->read_pdu(rnti, lcid, ue_rlc_buffer->msg, grant_size - 2);
-
-    // Only create PDU if RLC has something to tx
-    if (pdu_len > 0) {
-      logger.info("Adding MAC PDU for RNTI=%d", rnti);
-      ue_rlc_buffer->N_bytes = pdu_len;
-      logger.info(ue_rlc_buffer->msg, ue_rlc_buffer->N_bytes, "Read %d B from RLC", ue_rlc_buffer->N_bytes);
-
-      // add to MAC PDU and pack
-      mac_pdu_dl.add_sdu(4, ue_rlc_buffer->msg, ue_rlc_buffer->N_bytes);
-      mac_pdu_dl.pack();
-    }
-
-    if (logger.info.enabled()) {
-      fmt::memory_buffer str_buffer;
-      // mac_pdu_dl.to_string(str_buffer);
-      logger.info("0x%x %s", rnti, srsran::to_c_str(str_buffer));
-    }
-  } else {
-    logger.error(
-        "Invalid parameters calling generate_pdu: cc_idx=%d, harq_pid=%d, tb_idx=%d", enb_cc_idx, harq_pid, tb_idx);
+
+  mac_pdu_dl.init_tx(pdu, grant_size);
+
+  // read RLC PDU
+  ue_rlc_buffer->clear();
+  int lcid    = 4;
+  int pdu_len = rlc->read_pdu(rnti, lcid, ue_rlc_buffer->msg, grant_size - 2);
+
+  // Only create PDU if RLC has something to tx
+  if (pdu_len > 0) {
+    logger.info("Adding MAC PDU for RNTI=%d", rnti);
+    ue_rlc_buffer->N_bytes = pdu_len;
+    logger.info(ue_rlc_buffer->msg, ue_rlc_buffer->N_bytes, "Read %d B from RLC", ue_rlc_buffer->N_bytes);
+
+    // add to MAC PDU and pack
+    mac_pdu_dl.add_sdu(lcid, ue_rlc_buffer->msg, ue_rlc_buffer->N_bytes);
+  }
+
+  mac_pdu_dl.pack();
+
+  if (logger.info.enabled()) {
+    fmt::memory_buffer str_buffer;
+    // mac_pdu_dl.to_string(str_buffer);
+    logger.info("0x%x %s", rnti, srsran::to_c_str(str_buffer));
   }
-  return ret;
+  return SRSRAN_SUCCESS;
 }
 
 /******* METRICS interface ***************/
diff --git a/test/phy/dummy_gnb_stack.h b/test/phy/dummy_gnb_stack.h
index 73bb8d258..46abca3ce 100644
--- a/test/phy/dummy_gnb_stack.h
+++ b/test/phy/dummy_gnb_stack.h
@@ -202,7 +202,7 @@ private:
 
     // Set TBS
     // Select grant and set data
-    pdsch.data[0] = tx_harq_proc[slot_cfg.idx].get_tb(pdsch.sch.grant.tb[0].tbs).data();
+    pdsch.data[0] = tx_harq_proc[slot_cfg.idx].get_tb(pdsch.sch.grant.tb[0].tbs);
 
     // Set softbuffer
     pdsch.sch.grant.tb[0].softbuffer.tx = &tx_harq_proc[slot_cfg.idx].get_softbuffer(dci.ndi);
@@ -422,7 +422,7 @@ public:
       for (pdsch_t& pdsch : dl_sched.pdsch) {
         // Set TBS
         // Select grant and set data
-        pdsch.data[0] = tx_harq_proc[slot_cfg.idx].get_tb(pdsch.sch.grant.tb[0].tbs).data();
+        pdsch.data[0] = tx_harq_proc[slot_cfg.idx].get_tb(pdsch.sch.grant.tb[0].tbs);
         pdsch.data[1] = nullptr;
       }
 
diff --git a/test/phy/dummy_tx_harq_proc.h b/test/phy/dummy_tx_harq_proc.h
index d3a1631d2..c2fcb14fa 100644
--- a/test/phy/dummy_tx_harq_proc.h
+++ b/test/phy/dummy_tx_harq_proc.h
@@ -49,12 +49,12 @@ public:
     srsran_random_free(random_gen);
   }
 
-  srsran::byte_buffer_t& get_tb(uint32_t tbs_)
+  srsran::byte_buffer_t* get_tb(uint32_t tbs_)
   {
     std::unique_lock<std::mutex> lock(mutex);
     tbs = tbs_;
     srsran_random_byte_vector(random_gen, data.msg, tbs / 8);
-    return data;
+    return &data;
   }
 
   srsran_softbuffer_tx_t& get_softbuffer(uint32_t ndi_)
diff --git a/test/phy/dummy_ue_stack.h b/test/phy/dummy_ue_stack.h
index d2307ebed..70e555466 100644
--- a/test/phy/dummy_ue_stack.h
+++ b/test/phy/dummy_ue_stack.h
@@ -86,7 +86,7 @@ public:
       return;
     }
     action->tb.enabled    = true;
-    action->tb.payload    = &tx_harq_proc[grant.pid].get_tb(grant.tbs);
+    action->tb.payload    = tx_harq_proc[grant.pid].get_tb(grant.tbs);
     action->tb.softbuffer = &tx_harq_proc[grant.pid].get_softbuffer(grant.ndi);
   }
   void prach_sent(uint32_t tti, uint32_t s_id, uint32_t t_id, uint32_t f_id, uint32_t ul_carrier_id) override {}