wifi: Implement function to retrieve secondary band for a given width

src/wifi/model/phy-entity.cc

@@ -1042,6 +1042,13 @@ PhyEntity::GetPrimaryBand (uint16_t bandWidth) const
   return m_wifiPhy->GetBand (bandWidth, m_wifiPhy->m_operatingChannel.GetPrimaryChannelIndex (bandWidth));
 }
 
+WifiSpectrumBand
+PhyEntity::GetSecondaryBand (uint16_t bandWidth) const
+{
+  NS_ASSERT (m_wifiPhy->GetChannelWidth () >= 40);
+  return m_wifiPhy->GetBand (bandWidth, m_wifiPhy->m_operatingChannel.GetSecondaryChannelIndex (bandWidth));
+}
+
 uint16_t
 PhyEntity::GetRxChannelWidth (const WifiTxVector& txVector) const
 {

src/wifi/model/phy-entity.h

@@ -805,6 +805,16 @@ protected:
    * \return a pair of start and stop indexes that defines the band
    */
   WifiSpectrumBand GetPrimaryBand (uint16_t bandWidth) const;
+  /**
+   * If the channel bonding is used, return the start band index and the stop band index
+   * for the secondary channel of the given bandwidth (which must be a multiple of 20 MHz
+   * and not exceed the operating channel width).
+   *
+   * \param bandWidth the width of the band to be returned (MHz)
+   *
+   * \return a pair of start and stop indexes that defines the band
+   */
+  WifiSpectrumBand GetSecondaryBand (uint16_t bandWidth) const;
 
   /**
    * Return the channel width used to measure the RSSI.

src/wifi/model/wifi-phy-operating-channel.cc

@@ -437,10 +437,20 @@ WifiPhyOperatingChannel::GetPrimaryChannelIndex (uint16_t primaryChannelWidth) c
       index /= 2;
       width *= 2;
     }
-  NS_LOG_LOGIC ("Return " << +index);
+  NS_LOG_LOGIC ("Return primary index " << +index);
   return index;
 }
 
+uint8_t
+WifiPhyOperatingChannel::GetSecondaryChannelIndex (uint16_t secondaryChannelWidth) const
+{
+  NS_LOG_FUNCTION (this << secondaryChannelWidth);
+  const uint8_t primaryIndex = GetPrimaryChannelIndex (secondaryChannelWidth);
+  const uint8_t secondaryIndex = (primaryIndex % 2 == 0) ? (primaryIndex + 1) : (primaryIndex - 1);
+  NS_LOG_LOGIC ("Return secondary index " << +secondaryIndex);
+  return secondaryIndex;
+}
+
 void
 WifiPhyOperatingChannel::SetPrimary20Index (uint8_t index)
 {

src/wifi/model/wifi-phy-operating-channel.h

@@ -141,6 +141,17 @@ public:
    * \return the index of the requested primary channel within the operating channel
    */
   uint8_t GetPrimaryChannelIndex (uint16_t primaryChannelWidth) const;
+
+  /**
+   * If the operating channel width is made of a multiple of 20 MHz, return the index of the
+   * secondary channel of the given width within the operating channel (0 indicates
+   * the 20 MHz subchannel with the lowest center frequency). Otherwise, return 0.
+   *
+   * \param secondaryChannelWidth the width of the secondary channel in MHz
+   * \return the index of the requested secondary channel within the operating channel
+   */
+  uint8_t GetSecondaryChannelIndex (uint16_t secondaryChannelWidth) const;
+
   /**
    * Set the index of the primary 20 MHz channel (0 indicates the 20 MHz subchannel
    * with the lowest center frequency).