[GP-1111] mPower R. Apr 2021: +CEMODE shall be set to CEMODE=2

Fixed the `CellularRadio::getCarrier` implementation to use MCC/MNC
combination from the SIM intead of the serving cell.

Historically the implementation used MCC/MNC data from the cell that
is currently serving the device and provides the registration. This
MCC/MNC code is different from those of the home network in case of
a roaming - the network/carrier that provided the SIM is different
from the one who serves the device at the moment.

The more correct way to determine home carrier for GSM/UMTS/LTE devices
is to read first 5 or 6 digits of the SIM IMSI than encode the carrier.
This commit updates the implementation to use SIM IMSI as a source of
truth for the home network/carrier code.

1 files changed, 11 insertions, 16 deletions

diff --git a/src/MTS_IO_CellularRadio.cpp b/src/MTS_IO_CellularRadio.cpp
index 03baf48..1850a60 100644
--- a/src/MTS_IO_CellularRadio.cpp
+++ b/src/MTS_IO_CellularRadio.cpp
@@ -425,26 +425,21 @@ ICellularRadio::CODE CellularRadio::getType(std::string& sType) {
 
 ICellularRadio::CODE CellularRadio::getCarrier(std::string& sCarrier) {
     printTrace("%s| Get Carrier", m_sName.c_str());
-    if(m_sCarrier == "") {
-        Json::Value jData;
-        if(getNetworkStatus(jData) == SUCCESS) {
-            if(jData.isMember(ICellularRadio::KEY_MCC) && jData.isMember(ICellularRadio::KEY_MNC)) {
-                std::string sMcc = jData[ICellularRadio::KEY_MCC].asString();
-                std::string sMnc = jData[ICellularRadio::KEY_MNC].asString();
-                Json::Value jLookup = MccMncTable::getInstance()->lookup(sMcc, sMnc);
-                printTrace("%s| MCC-MNC Lookup: [%s][%s][%s]", m_sName.c_str(),
-                           sMcc.c_str(), sMnc.c_str(), jLookup.toStyledString().c_str());
-                if(jLookup.isMember(ICellularRadio::KEY_CARRIER)) {
-                    m_sCarrier = jLookup[ICellularRadio::KEY_CARRIER].asString();
-                } else {
-                    printWarning("%s| MCC-MNC Lookup did not contain carrier", m_sName.c_str());
-                    return FAILURE;
-                }
+    if (m_sCarrier == "") {
+        std::string sMcc;
+        std::string sMnc;
+        if (getSimMccMnc(sMcc, sMnc) == CODE::SUCCESS) {
+            Json::Value jLookup = MccMncTable::getInstance()->lookup(sMcc, sMnc);
+            printTrace("%s| MCC-MNC Lookup: [%s][%s][%s]", m_sName.c_str(),
+                       sMcc.c_str(), sMnc.c_str(), jLookup.toStyledString().c_str());
+            if (jLookup.isMember(ICellularRadio::KEY_CARRIER)) {
+                m_sCarrier = jLookup[ICellularRadio::KEY_CARRIER].asString();
             } else {
-                printWarning("%s| Network Status did no contain MCC or MNC", m_sName.c_str());
+                printWarning("%s| MCC-MNC Lookup did not contain carrier", m_sName.c_str());
                 return FAILURE;
             }
         } else {
+            printWarning("%s| SIM did no contain MCC or MNC", m_sName.c_str());
             return FAILURE;
         }
     }