made SINR threshold check bidirectional

@miSim/constrainMotion.m

@@ -169,11 +169,11 @@ function [obj] = constrainMotion(obj)
             end
         end
     else
-        % SINR comms: keep the SINR of each maintained link above threshold via
+        % SINR comms: a link is feasible only if each agent receives the other
-        % the barrier h = SINR - gammaLin. Per the connectivity convention the
+        % above threshold, so every maintained pair is held with TWO barrier
-        % lower-index agent (ii) receives the higher-index transmitter (jj). The
+        % rows, h = SINR - gammaCbf, one per receiver direction. Each gradient
-        % gradient couples the receiver, transmitter, and every interferer, so
+        % couples the receiver, transmitter, and every interferer, so the QP
-        % the QP row is dense across all agent blocks.
+        % rows are dense across all agent blocks.
         % Maintain SINR a margin above the connectivity threshold so that
         % discrete-time overshoot of the (convex) SINR does not transiently
         % drop a maintained link below threshold. Mirrors the fixed-radius
@@ -188,19 +188,33 @@ function [obj] = constrainMotion(obj)
         for ii = 1:(nAgents - 1)
             for jj = (ii + 1):nAgents
                 if obj.constraintAdjacencyMatrix(ii, jj)
-                    [sinr, grad] = obj.sinrLink(lastPositions, ii, jj); % receiver ii, transmitter jj
+                    % Direction 1: lower-index agent (ii) receives higher (jj).
-                    hComms(ii, jj) = sinr - gammaCbf;
+                    % Upper triangle of hComms stores this direction's barrier.
-
+                    [sinr1, grad1] = obj.sinrLink(lastPositions, ii, jj);
+                    hComms(ii, jj) = sinr1 - gammaCbf;
                     % CBF row: A = -grad(h), b = h/dt (one-step forward invariance)
                     for aa = 1:nAgents
-                        A(kk, (3 * aa - 2):(3 * aa)) = -grad(aa, :);
+                        A(kk, (3 * aa - 2):(3 * aa)) = -grad1(aa, :);
                     end
                     if norm(A(kk, :)) < 1e-9
                         b(kk) = 0;
                     else
                         b(kk) = hComms(ii, jj) / obj.timestep;
                     end
+                    kk = kk + 1;
 
+                    % Direction 2: higher-index agent (jj) receives lower (ii).
+                    % Lower triangle of hComms stores this direction's barrier.
+                    [sinr2, grad2] = obj.sinrLink(lastPositions, jj, ii);
+                    hComms(jj, ii) = sinr2 - gammaCbf;
+                    for aa = 1:nAgents
+                        A(kk, (3 * aa - 2):(3 * aa)) = -grad2(aa, :);
+                    end
+                    if norm(A(kk, :)) < 1e-9
+                        b(kk) = 0;
+                    else
+                        b(kk) = hComms(jj, ii) / obj.timestep;
+                    end
                     kk = kk + 1;
                 end
             end
@@ -208,7 +222,15 @@ function [obj] = constrainMotion(obj)
     end
 
     if coder.target('MATLAB')
-	obj.barriers(idx:(idx + length(hComms(triu(true(size(hComms)), 1))) - 1), obj.timestepIndex) = hComms(triu(true(size(hComms)), 1));
+        if obj.useSinrComms
+            % Both directions are maintained: log the upper triangle
+            % (lower-index receiver) then the lower triangle (higher-index
+            % receiver), matching the doubled comms-barrier allocation.
+            commsLog = [hComms(triu(true(size(hComms)), 1)); hComms(tril(true(size(hComms)), -1))];
+        else
+            commsLog = hComms(triu(true(size(hComms)), 1));
+        end
+        obj.barriers(idx:(idx + numel(commsLog) - 1), obj.timestepIndex) = commsLog;
     end
 
     % Double-integrator: transform QP from velocity to acceleration space.

@miSim/initialize.m

@@ -143,8 +143,13 @@ function [obj] = initialize(obj, domain, agents, barrierGain, barrierExponent, m
     % Comms barriers: size to the upper bound (full mesh) rather than the initial
     % constraint-adjacency count. Connectivity is dynamic (lesser-neighbor and,
     % especially, SINR) and can later maintain more pairs than at init; sizing to
-    % nAAPairs prevents the QP A/b matrices from overflowing mid-run.
+    % nAAPairs prevents the QP A/b matrices from overflowing mid-run. SINR mode
+    % enforces both directions per link, so it needs two barrier rows per pair.
+    if obj.useSinrComms
+        nLNAPairs = 2 * nAAPairs;
+    else
         nLNAPairs = nAAPairs;
+    end
     obj.numBarriers = nAAPairs + nAOPairs + nADPairs + nLNAPairs;
 
     if coder.target('MATLAB')

@miSim/plotGraph.m

@@ -36,15 +36,19 @@ function obj = plotGraph(obj)
         for kk = 1:nAgents
             positions(kk, :) = obj.agents{kk}.pos;
         end
-        % Directional convention (matches updateAdjacency/constrainMotion):
+        % A link is feasible only if BOTH directions clear the threshold, so
-        % the lower-index node is the receiver, the higher-index node the
+        % label each edge with the binding (worse) directional SINR: the min of
-        % transmitter, with interference from all other agents at the receiver.
+        % the lower-index-receiver and higher-index-receiver links, with
-        % Labels are bare numbers (no units) so they stay compact; GraphPlot
+        % interference from all other agents at each receiver. Labels are bare
-        % renders them horizontally, left-to-right.
+        % numbers (no units) so they stay compact; GraphPlot renders them
+        % horizontally, left-to-right.
         edgeLabels = strings(size(endNodes, 1), 1);
         for ee = 1:size(endNodes, 1)
-            sinrLin = obj.sinrLink(positions, endNodes(ee, 1), endNodes(ee, 2));
+            lo = endNodes(ee, 1);
-            edgeLabels(ee) = sprintf("%.1f", 10 * log10(sinrLin));
+            hi = endNodes(ee, 2);
+            sinrLoRx = obj.sinrLink(positions, lo, hi); % receiver lo (lower index)
+            sinrHiRx = obj.sinrLink(positions, hi, lo); % receiver hi (higher index)
+            edgeLabels(ee) = sprintf("%.1f", 10 * log10(min(sinrLoRx, sinrHiRx)));
         end
         o(1).EdgeLabel = edgeLabels;
         % Threshold goes in the existing single-line title (not a subtitle) so

@miSim/updateAdjacency.m

@@ -23,9 +23,11 @@ function obj = updateAdjacency(obj)
             end
         end
     else
-        % SINR model: pair (ii, jj) connected iff the lower-index agent (jj)
+        % SINR model: a link between a pair is feasible only if BOTH directional
-        % receives the higher-index agent's (ii) signal above the SINR
+        % SINRs clear the threshold, i.e. each agent receives the other's signal
-        % threshold, with interference from all other agents at the receiver.
+        % above gammaLin (with interference from all other agents at the
+        % receiver). Every ordered pair (permutation) is evaluated; a single
+        % failing direction eliminates the undirected link.
         gammaLin = 10^(obj.sinrThreshold / 10); % dB threshold -> linear
         positions = zeros(nAgents, 3);
         for kk = 1:nAgents
@@ -33,9 +35,10 @@ function obj = updateAdjacency(obj)
         end
         for ii = 2:nAgents
             for jj = 1:(ii - 1)
-                sinr = obj.sinrLink(positions, jj, ii); % receiver jj, transmitter ii
+                sinrLoRx = obj.sinrLink(positions, jj, ii); % receiver jj (lower), transmitter ii
-                if sinr < gammaLin
+                sinrHiRx = obj.sinrLink(positions, ii, jj); % receiver ii (higher), transmitter jj
-                    A(ii, jj) = false; % SINR below threshold
+                if sinrLoRx < gammaLin || sinrHiRx < gammaLin
+                    A(ii, jj) = false; % at least one direction below threshold
                     continue;
                 end
             end

test/test_miSim.m

@@ -857,18 +857,19 @@ classdef test_miSim < matlab.unittest.TestCase
             % fixed-radius variant of this test (so the two agents still cannot
             % reach their objectives without breaking connectivity).
             useSinrComms     = true;
-            txPower          = 0.1;     % transmit power per agent (W)
+            txPower          = [0.01, 0.01];     % transmit power per agent (W)
             pathLossExponent = 2.0;
             ambientTemp      = 290;     % K
             centerFreq       = 2.4e9;   % Hz
             bandwidth        = 20e6;    % Hz
+
             effRange         = 4.0;     % desired effective comms range (m)
             K_pl   = (4 * pi * centerFreq / 3e8)^2;            % free-space path-loss reference
             noiseW = 1.380649e-23 * ambientTemp * bandwidth;   % thermal noise (W)
-            sinrThreshold = 10 * log10(txPower / (K_pl * effRange^pathLossExponent * noiseW)); % dB
+            sinrThreshold = 10 * log10(mean(txPower) / (K_pl * effRange^pathLossExponent * noiseW)); % dB
 
-            tc.agents{1}.txPower = txPower;
+            tc.agents{1}.txPower = txPower(1);
-            tc.agents{2}.txPower = txPower;
+            tc.agents{2}.txPower = txPower(2);
 
             % Initialize the simulation in SINR comms mode
             tc.testClass = tc.testClass.initialize(tc.domain, tc.agents, tc.barrierGain, tc.barrierExponent, tc.minAlt, tc.timestep, tc.maxIter, tc.obstacles, tc.makePlots, tc.makeVideo, tc.useDoubleIntegrator, tc.dampingCoeff, tc.useFixedTopology, tc.optimizeSensorPointing, useSinrComms, sinrThreshold, pathLossExponent, ambientTemp, centerFreq, bandwidth);