diff --git a/srsue/hdr/stack/upper/pcsc_usim.h b/srsue/hdr/stack/upper/pcsc_usim.h
index d0dd9f1e8..3694bf446 100644
--- a/srsue/hdr/stack/upper/pcsc_usim.h
+++ b/srsue/hdr/stack/upper/pcsc_usim.h
@@ -56,6 +56,9 @@ public:
                                                  int*     res_len,
                                                  uint8_t* k_asme);
 
+  // Helpers
+  virtual std::string get_mnc_str(const uint8_t* imsi_vec, std::string mcc_str) final;
+
 private:
   // Smartcard sub-class which is a port of the PC/SC smartcard implementation
   // of WPA Supplicant written by Jouni Malinen <j@w1.fi> and licensed under BSD
diff --git a/srsue/hdr/stack/upper/usim.h b/srsue/hdr/stack/upper/usim.h
index 72a6d81be..519559a91 100644
--- a/srsue/hdr/stack/upper/usim.h
+++ b/srsue/hdr/stack/upper/usim.h
@@ -62,7 +62,10 @@ private:
                                  uint8_t* res,
                                  int*     res_len,
                                  uint8_t* k_asme);
-  void          str_to_hex(std::string str, uint8_t* hex);
+
+  // Helpers
+  virtual std::string get_mnc_str(const uint8_t* imsi_vec, std::string mcc_str) final;
+  void                str_to_hex(std::string str, uint8_t* hex);
 
   // User data
   auth_algo_t auth_algo = auth_algo_milenage;
diff --git a/srsue/hdr/stack/upper/usim_base.h b/srsue/hdr/stack/upper/usim_base.h
index 9a2360ba1..3349ef372 100644
--- a/srsue/hdr/stack/upper/usim_base.h
+++ b/srsue/hdr/stack/upper/usim_base.h
@@ -101,6 +101,10 @@ public:
   void store_keys_before_ho(const srslte::as_security_config_t& as_ctx) final;
   void restore_keys_from_failed_ho(srslte::as_security_config_t* as_ctx) final;
 
+  // Helpers
+  std::string         get_mcc_str(const uint8_t* imsi_vec);
+  virtual std::string get_mnc_str(const uint8_t* imsi_vec, std::string mcc_str) = 0;
+
 protected:
   bool initiated = false;
 
@@ -113,7 +117,6 @@ protected:
   uint64_t    imei = 0;
   std::string imsi_str;
   std::string imei_str;
-  uint32_t    mnc_length = 0;
 
   // Security variables
   uint8_t ck[CK_LEN]             = {};
diff --git a/srsue/src/stack/upper/pcsc_usim.cc b/srsue/src/stack/upper/pcsc_usim.cc
index b5eb2af81..304d54eed 100644
--- a/srsue/src/stack/upper/pcsc_usim.cc
+++ b/srsue/src/stack/upper/pcsc_usim.cc
@@ -91,10 +91,6 @@ int pcsc_usim::init(usim_args_t* args)
     return ret;
   }
 
-  // Get MNC length
-  mnc_length = sc.get_mnc_len();
-  log->debug("MNC length %d\n", mnc_length);
-
   initiated = true;
   ret       = SRSLTE_SUCCESS;
 
@@ -163,6 +159,19 @@ auth_result_t pcsc_usim::generate_authentication_response(uint8_t* rand,
   return ret;
 }
 
+std::string pcsc_usim::get_mnc_str(const uint8_t* imsi_vec, std::string mcc_str)
+{
+  uint32_t           mcc_len = 3;
+  uint32_t           mnc_len = sc.get_mnc_len();
+  std::ostringstream mnc_oss;
+
+  for (uint32_t i = mcc_len; i < mcc_len + mnc_len; i++) {
+    mnc_oss << (int)imsi_vec[i];
+  }
+
+  return mnc_oss.str();
+}
+
 /*********************************
  * PC/SC class
  ********************************/
diff --git a/srsue/src/stack/upper/usim.cc b/srsue/src/stack/upper/usim.cc
index 496b744f7..3895f876b 100644
--- a/srsue/src/stack/upper/usim.cc
+++ b/srsue/src/stack/upper/usim.cc
@@ -248,6 +248,25 @@ auth_result_t usim::gen_auth_res_xor(uint8_t* rand,
   return result;
 }
 
+std::string usim::get_mnc_str(const uint8_t* imsi_vec, std::string mcc_str)
+{
+  uint32_t           mcc_len = 3;
+  uint32_t           mnc_len = 2;
+  std::ostringstream mnc_oss;
+
+  // US MCC uses 3 MNC digits
+  if (!mcc_str.compare("310") || !mcc_str.compare("311") || !mcc_str.compare("312") || !mcc_str.compare("313") ||
+      !mcc_str.compare("316")) {
+    mnc_len = 3;
+  }
+
+  for (uint32_t i = mcc_len; i < mcc_len + mnc_len; i++) {
+    mnc_oss << (int)imsi_vec[i];
+  }
+
+  return mnc_oss.str();
+}
+
 void usim::str_to_hex(std::string str, uint8_t* hex)
 {
   uint32_t    i;
diff --git a/srsue/src/stack/upper/usim_base.cc b/srsue/src/stack/upper/usim_base.cc
index a2ab22c30..b50cff94e 100644
--- a/srsue/src/stack/upper/usim_base.cc
+++ b/srsue/src/stack/upper/usim_base.cc
@@ -96,6 +96,16 @@ bool usim_base::get_imei_vec(uint8_t* imei_, uint32_t n)
   return true;
 }
 
+std::string usim_base::get_mcc_str(const uint8_t* imsi_vec)
+{
+  std::ostringstream mcc_oss;
+  uint32_t           mcc_len = 3;
+  for (uint32_t i = 0; i < mcc_len; i++) {
+    mcc_oss << (int)imsi_vec[i];
+  }
+  return mcc_oss.str();
+}
+
 bool usim_base::get_home_plmn_id(srslte::plmn_id_t* home_plmn_id)
 {
   if (!initiated) {
@@ -106,18 +116,11 @@ bool usim_base::get_home_plmn_id(srslte::plmn_id_t* home_plmn_id)
   uint8_t imsi_vec[15];
   get_imsi_vec(imsi_vec, 15);
 
-  std::ostringstream plmn_str;
+  std::string mcc_str = get_mcc_str(imsi_vec);
+  std::string mnc_str = get_mnc_str(imsi_vec, mcc_str);
 
-  uint mcc_len = 3;
-  for (uint i = 0; i < mcc_len; i++) {
-    plmn_str << (int)imsi_vec[i];
-  }
-
-  for (uint i = mcc_len; i < mcc_len + mnc_length; i++) {
-    plmn_str << (int)imsi_vec[i];
-  }
-
-  if (home_plmn_id->from_string(plmn_str.str())) {
+  std::string plmn_str = mcc_str + mnc_str;
+  if (home_plmn_id->from_string(plmn_str)) {
     log->error("Error reading home PLMN from SIM.\n");
     return false;
   }