From 4dd21b151c465ff46d011e069782ee8ba518a96b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Deronne?= <sebastien.deronne@gmail.com>
Date: Fri, 13 Jan 2017 20:10:40 +0100
Subject: [PATCH] wifi: (fixes #2601) HT stations use 40 MHz channel width if
 the configured channel width is set to 80 or 160 MHz

---
 RELEASE_NOTES                      |  1 +
 src/wifi/model/regular-wifi-mac.cc |  4 +--
 src/wifi/model/wifi-mode.cc        | 46 +++++++++++++++++++++---------
 3 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 5f0dac292..ed9c41df6 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -61,6 +61,7 @@ Bugs fixed
 - Bug 2590 - Minor enhancements in red-queue-disc{.h, .cc}
 - Bug 2591 - 802.11e Block Ack mechanism cannot be enabled on HT/VHT stations
 - Bug 2594 - vht-wifi-network provides very low throughtput at MCS 6, 160 MHz, SGI
+- Bug 2601 - HT stations should use 40 MHz channel width if the configured channel width is set to 80 or 160 MHz
 - Bug 2605 - A HT/VHT station transmitting to a legacy access point results in a null throughput
 - Bug 2607 - Minstrel HT manager results in an endless loop when a 802.11ac station is transmitting to a 802.11a access point
 - Bug 2614 - RIP header version should be set to 2
diff --git a/src/wifi/model/regular-wifi-mac.cc b/src/wifi/model/regular-wifi-mac.cc
index 1dc35ffe4..d28e60008 100644
--- a/src/wifi/model/regular-wifi-mac.cc
+++ b/src/wifi/model/regular-wifi-mac.cc
@@ -146,9 +146,9 @@ RegularWifiMac::GetHtCapabilities (void) const
       capabilities.SetHtSupported (1);
       capabilities.SetHtSupported (1);
       capabilities.SetLdpc (m_phy->GetLdpc ());
-      capabilities.SetSupportedChannelWidth (m_phy->GetChannelWidth () == 40);
+      capabilities.SetSupportedChannelWidth (m_phy->GetChannelWidth () >= 40);
       capabilities.SetShortGuardInterval20 (m_phy->GetGuardInterval ());
-      capabilities.SetShortGuardInterval40 (m_phy->GetChannelWidth () == 40 && m_phy->GetGuardInterval ());
+      capabilities.SetShortGuardInterval40 (m_phy->GetChannelWidth () >= 40 && m_phy->GetGuardInterval ());
       capabilities.SetGreenfield (m_phy->GetGreenfield ());
       capabilities.SetMaxAmsduLength (1); //hardcoded for now (TBD)
       capabilities.SetLSigProtectionSupport (!m_phy->GetGreenfield ());
diff --git a/src/wifi/model/wifi-mode.cc b/src/wifi/model/wifi-mode.cc
index b7642d8c1..71d369a25 100644
--- a/src/wifi/model/wifi-mode.cc
+++ b/src/wifi/model/wifi-mode.cc
@@ -210,21 +210,39 @@ WifiMode::GetDataRate (uint8_t channelWidth, bool isShortGuardInterval, uint8_t
           symbolRate = (1 / 3.6) * 1e6;
         }
 
-      switch (channelWidth)
+      if (item->modClass == WIFI_MOD_CLASS_HT)
         {
-        case 20:
-        default:
-          usableSubCarriers = 52;
-          break;
-        case 40:
-          usableSubCarriers = 108;
-          break;
-        case 80:
-          usableSubCarriers = 234;
-          break;
-        case 160:
-          usableSubCarriers = 468;
-          break;
+          switch (channelWidth)
+            {
+            case 20:
+            default:
+              usableSubCarriers = 52;
+              break;
+            case 40:
+            case 80:
+            case 160:
+              usableSubCarriers = 108;
+              break;
+            }
+        }
+      else //WIFI_MOD_CLASS_VHT
+        {
+          switch (channelWidth)
+            {
+            case 20:
+            default:
+              usableSubCarriers = 52;
+              break;
+            case 40:
+              usableSubCarriers = 108;
+              break;
+            case 80:
+              usableSubCarriers = 234;
+              break;
+            case 160:
+              usableSubCarriers = 468;
+              break;
+            }
         }
 
       switch (GetCodeRate ())