Display link score instead of RSSI

Author: floppyhammer

src/gui/player_rect.cpp

@@ -189,11 +189,11 @@ void PlayerRect::custom_ready() {
         }
 
         for (int i = 0; i != GuiInterface::Instance().links_.size(); ++i) {
-            auto rssi = GuiInterface::Instance().links_[i]->get_rssi();
+            auto link_score = GuiInterface::Instance().links_[i]->get_link_score();
 
             for (int j = 0; j != ANTENNA_COUNT; ++j) {
                 lq_bars_[i * 2 + j]->set_visibility(true);
-                lq_bars_[i * 2 + j]->set_value(rssi[j]);
+                lq_bars_[i * 2 + j]->set_value(link_score[j]);
             }
         }
 

src/wifi/signal_quality.cpp

@@ -78,12 +78,13 @@ SignalQualityCalculator::SignalQuality SignalQualityCalculator::calculate_signal
     auto avg_snr = get_average(snr_data_);
 
     // Map the RSSI from range 0..126 to 0..100
-    avg_rssi.first = map_range(avg_rssi.first, 0.f, 126.f, 0.f, 100.f);
-    avg_rssi.second = map_range(avg_rssi.second, 0.f, 126.f, 0.f, 100.f);
+    float rssi0 = map_range(avg_rssi.first, 0.f, 126.f, 0.f, 100.f);
+    float rssi1 = map_range(avg_rssi.second, 0.f, 126.f, 0.f, 100.f);
+
+    // Map the SNR from range 0..60 to 0..100
+    float snr0 = map_range(avg_snr.first, 0.f, 60.f, 0.f, 100.f);
+    float snr1 = map_range(avg_snr.second, 0.f, 60.f, 0.f, 100.f);
 
-    // Return final clamped quality
-    // formula: quality = avg_rssi - p_recovered * 5 - p_lost * 100
-    // clamp between -1024 and 1024
     auto [p_recovered, p_lost, p_total] = get_accumulated_fec_data();
 
     ret.lost_last_second = p_lost;
@@ -96,6 +97,10 @@ SignalQualityCalculator::SignalQuality SignalQualityCalculator::calculate_signal
     ret.snr[1] = avg_snr.second;
     ret.idr_code = idr_code_;
 
+    // Link Quality = (w1 * RSSI) + (w2 * SNR)
+    ret.link_score[0] = 0.3f * rssi0 + 0.7f * snr0;
+    ret.link_score[1] = 0.3f * rssi1 + 0.7f * snr1;
+
     return ret;
 }
 

src/wifi/signal_quality.h

@@ -21,8 +21,9 @@ class SignalQualityCalculator {
         int lost_last_second;
         int recovered_last_second;
         int total_last_second;
-        float rssi[2]; // [0, 100]
-        float snr[2];  // Signal to noice ratio
+        float rssi[2];       // Received signal strength indicator
+        float snr[2];        // Signal to noice ratio
+        float link_score[2]; // Based on RSSI and SNR [0, 100]
         std::string idr_code;
     };
 

src/wifi/wfbng_link.cpp

@@ -442,8 +442,13 @@ void WfbngLink::start_link_quality_thread() {
         while (!this->alink_should_stop) {
             auto quality = signal_quality_calculator->calculate_signal_quality();
 
-            float best_rssi = std::max(quality.rssi[0], quality.rssi[1]);
+            // Best values of the antennas.
+            float best_rssi = round(std::max(quality.rssi[0], quality.rssi[1]));
             float best_snr = std::max(quality.snr[0], quality.snr[1]);
+            float best_lq = std::max(quality.lq[0], quality.lq[1]);
+
+            // Map to 1000..2000
+            int lq_for_uplink = round(map_range(best_lq, 0, 100, 1000, 2000));
 
             if (quality.total_last_second != 0) {
                 packet_loss_ =
@@ -454,9 +459,6 @@ void WfbngLink::start_link_quality_thread() {
 
             time_t currentEpoch = time(nullptr);
 
-            // Map to 1000..2000
-            best_rssi = map_range(best_rssi, 0, 100, 1000, 2000);
-
             // Prepare & send a message
             {
                 uint32_t len;
@@ -510,8 +512,8 @@ void WfbngLink::start_link_quality_thread() {
                          sizeof(message) - sizeof(len),
                          "%ld:%d:%d:%d:%d:%d:%f:0:-1:%d:%s\n",
                          static_cast<long>(currentEpoch),
-                         best_rssi,
-                         best_rssi,
+                         lq_for_uplink,
+                         lq_for_uplink,
                          quality.recovered_last_second,
                          quality.lost_last_second,
                          best_rssi,
@@ -660,8 +662,8 @@ void WfbngLink::handle_80211_frame(const Packet &packet) {
 #endif
 
         const auto quality = signal_quality_calculator->calculate_signal_quality();
-        rssi_[0] = quality.rssi[0];
-        rssi_[1] = quality.rssi[1];
+        link_score_[0] = quality.link_score[0];
+        link_score_[1] = quality.link_score[1];
     }
     // MAVLink frame
     else if (frame.MatchesChannelID(mavlink_channel_id_be8)) {
@@ -688,8 +690,8 @@ void WfbngLink::handle_80211_frame(const Packet &packet) {
     }
 }
 
-std::array<float, ANTENNA_COUNT> WfbngLink::get_rssi() const {
-    return rssi_;
+std::array<float, ANTENNA_COUNT> WfbngLink::get_link_score() const {
+    return link_score_;
 }
 
 float WfbngLink::get_packet_loss() const {

src/wifi/wfbng_link.h

@@ -73,7 +73,7 @@ class WfbngLink {
     /// Process a 802.11 frame.
     void handle_80211_frame(const Packet &packet);
 
-    std::array<float, ANTENNA_COUNT> get_rssi() const;
+    std::array<float, ANTENNA_COUNT> get_link_score() const;
 
     float get_packet_loss() const;
 
@@ -107,8 +107,8 @@ class WfbngLink {
 #endif
 
     std::shared_ptr<SignalQualityCalculator> signal_quality_calculator;
-    std::array<float, ANTENNA_COUNT> rssi_ = {}; // Percentage
-    float packet_loss_ = 0;                      // Percentage
+    std::array<float, ANTENNA_COUNT> link_score_ = {}; // Percentage
+    float packet_loss_ = 0;                            // Percentage
 
 #ifndef _WIN32
     // --------------- Adaptive link