124 lines
3.2 KiB
JavaScript
124 lines
3.2 KiB
JavaScript
// RF Coverage Calculation Web Worker
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// Runs in a separate thread for parallel processing
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self.onmessage = function (e) {
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const { type, sites, points, rsrpThreshold } = e.data;
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if (type === 'calculate') {
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try {
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const results = [];
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for (let i = 0; i < points.length; i++) {
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const point = points[i];
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let bestRSRP = -Infinity;
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let bestSiteId = '';
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for (let j = 0; j < sites.length; j++) {
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const site = sites[j];
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const rsrp = calculatePointRSRP(site, point);
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if (rsrp > bestRSRP) {
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bestRSRP = rsrp;
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bestSiteId = site.id;
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}
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}
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if (bestRSRP >= rsrpThreshold) {
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results.push({
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lat: point.lat,
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lon: point.lon,
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rsrp: bestRSRP,
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siteId: bestSiteId,
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});
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}
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}
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self.postMessage({ type: 'complete', results });
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} catch (error) {
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self.postMessage({ type: 'error', message: error.message });
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}
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}
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};
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/**
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* Calculate RSRP at a specific point (universal formula)
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*/
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function calculatePointRSRP(site, point) {
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var distance = haversineDistance(site.lat, site.lon, point.lat, point.lon);
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// Minimum distance to prevent -Infinity
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if (distance < 0.01) distance = 0.01;
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// Free space path loss (universal)
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var fspl =
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20 * Math.log10(distance) + 20 * Math.log10(site.frequency) + 32.45;
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// Link budget: RSRP = P_tx + G_tx - FSPL
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var rsrp = site.power + site.gain - fspl;
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// Apply sector antenna pattern loss
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if (site.antennaType === 'sector' && site.azimuth !== undefined) {
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var bearing = calculateBearing(site.lat, site.lon, point.lat, point.lon);
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var relativeAngle = Math.abs(bearing - site.azimuth);
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var normalizedAngle =
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relativeAngle > 180 ? 360 - relativeAngle : relativeAngle;
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var patternLoss = calculateSectorPatternLoss(
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normalizedAngle,
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site.beamwidth || 65
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);
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rsrp -= patternLoss;
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}
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return rsrp;
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}
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/**
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* Haversine distance in km
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*/
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function haversineDistance(lat1, lon1, lat2, lon2) {
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var R = 6371;
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var dLat = ((lat2 - lat1) * Math.PI) / 180;
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var dLon = ((lon2 - lon1) * Math.PI) / 180;
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var a =
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Math.sin(dLat / 2) * Math.sin(dLat / 2) +
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Math.cos((lat1 * Math.PI) / 180) *
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Math.cos((lat2 * Math.PI) / 180) *
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Math.sin(dLon / 2) *
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Math.sin(dLon / 2);
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var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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return R * c;
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}
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/**
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* Calculate bearing from A to B in degrees (0-360)
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*/
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function calculateBearing(lat1, lon1, lat2, lon2) {
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var dLon = ((lon2 - lon1) * Math.PI) / 180;
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var lat1Rad = (lat1 * Math.PI) / 180;
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var lat2Rad = (lat2 * Math.PI) / 180;
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var y = Math.sin(dLon) * Math.cos(lat2Rad);
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var x =
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Math.cos(lat1Rad) * Math.sin(lat2Rad) -
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Math.sin(lat1Rad) * Math.cos(lat2Rad) * Math.cos(dLon);
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var bearing = (Math.atan2(y, x) * 180) / Math.PI;
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return (bearing + 360) % 360;
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}
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/**
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* Sector antenna pattern loss (3GPP model)
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*/
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function calculateSectorPatternLoss(angleOffBoresight, beamwidth) {
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var theta3dB = beamwidth / 2;
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var sideLobeLevel = 20;
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return Math.min(
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12 * Math.pow(angleOffBoresight / theta3dB, 2),
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sideLobeLevel
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);
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}
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