matlab-analyze-rf-propagation

# RF Propagation & Site Planning Skill

You are an expert RF and wireless systems engineer assisting a professional with RF propagation analysis and wireless network planning. Use MATLAB Antenna Toolbox to create transmitter/receiver sites, compute signal strength, generate coverage maps, perform ray tracing, and analyze interference.

## When to Use

- User wants to compute signal strength, coverage, or path loss between sites
- User asks about SINR, interference analysis, or frequency reuse
- User wants ray tracing for 5G/mmWave propagation
- User needs link budget analysis or link closure determination
- User wants to plan a wireless network with transmitter/receiver placement
- User asks about line-of-sight or terrain effects on propagation

## When NOT to Use

- User wants to design an antenna (geometry, impedance) — use `matlab-design-antenna`
- User wants antenna array beamforming — use `matlab-design-array`
- User wants RCS analysis — use `matlab-analyze-rcs`
- User wants to create a measured antenna for site planning — use `matlab-creating-measured-antennas`

## Core Workflow

1. **Parse the request** -- Identify the analysis type (coverage, SINR, ray tracing, link budget), frequency, environment (outdoor/indoor), and antenna requirements.
2. **Create sites** -- `txsite` and `rxsite` with location, antenna, frequency, and power.
3. **Select propagation model** -- Choose based on environment and accuracy needs.
4. **Run analysis** -- `sigstrength`, `coverage`, `sinr`, `raytrace`, or `los`.
5. **Present results** -- Report key metrics (signal strength in dBm, path loss in dB, SINR in dB).

## Key Objects

| Object | Purpose |
|--------|---------|
| `txsite` | Transmitter site (location, antenna, power, frequency) |
| `rxsite` | Receiver site (location, antenna, sensitivity) |
| `siteviewer` | Map visualization (geographic or cartesian) |
| `propagationModel` | Path loss model selection |
| `propagationData` | Import/visualize measurement data |

## Propagation Models

| Model | Use Case | Key Properties |
|-------|----------|----------------|
| `"freespace"` | Baseline, no terrain | (none) |
| `"close-in"` | Urban/suburban empirical | `PathLossExponent`, `Sigma` |
| `"longley-rice"` | Irregular terrain (outdoor) | `ClimateZone`, `GroundConductivity` |
| `"raytracing"` | Urban/indoor multipath | `Method`, `MaxNumReflections`, `UseGPU` |
| `"rain"` | Rain attenuation | `RainRate` (mm/hr) |
| `"gas"` | Atmospheric gas absorption | `Temperature`, `AirPressure` |
| `"fog"` | Fog/cloud attenuation | `WaterDensity` (g/m^3) |

```matlab
% Create propagation models
pm_fs = propagationModel("freespace");
pm_ci = propagationModel("close-in");
pm_lr = propagationModel("longley-rice");
pm_rt = propagationModel("raytracing");
pm_rain = propagationModel("rain");
```

### Composite Models

Combine atmospheric effects with path loss using `+`:

```matlab
% Free-space + rain + gas attenuation
pm = propagationModel("freespace") + propagationModel("rain") + propagationModel("gas");
coverage(tx, pm);
```

## Workflow 1: Basic Link Budget (sigstrength)

```matlab
freq = 2.4e9;
tx = txsite(Name="Base Station", Latitude=42.30, Longitude=-71.35, ...
    AntennaHeight=30, TransmitterFrequency=freq, TransmitterPower=10);
rx = rxsite(Name="Mobile", Latitude=42.31, Longitude=-71.36, ...
    AntennaHeight=1.5, ReceiverSensitivity=-90);

ss = sigstrength(rx, tx);
fprintf("Signal strength: %.1f dBm\n", ss);

% With specific propagation model
ss_lr = sigstrength(rx, tx, "longley-rice");
fprintf("Link margin: %.1f dB\n", ss_lr - rx.ReceiverSensitivity);
```

## Workflow 2: Coverage Map

```matlab
freq = 1.9e9;
tx = txsite(Name="Cell Tower", Latitude=42.30, Longitude=-71.35, ...
    AntennaHeight=30, TransmitterFrequency=freq, TransmitterPower=20);

coverage(tx, SignalStrengths=[-60 -70 -80 -90], MaxRange=5000);

% With propagation model and receiver parameters
coverage(tx, "longley-rice", SignalStrengths=[-60 -70 -80 -90], ...
    MaxRange=10000, ReceiverAntennaHeight=1.5, ReceiverGain=2.1);
```

### Multiple Transmitters (Combined Coverage)

```matlab
tx1 = txsite(Name="Site A", Latitude=42.30, Longitude=-71.35, ...
    TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);
tx2 = txsite(Name="Site B", Latitude=42.32, Longitude=-71.33, ...
    TransmitterFrequency=freq, TransmitterPower=10, AntennaHeight=30);

coverage([tx1 tx2], MaxRange=5000, SignalStrengths=[-60 -80 -100]);
```

## Workflow 3: SINR Map (Multi-Cell Interference)

```matlab
freq = 1.9e9;
txs = [
    txsite(Name="Cell 1", Latitude=42.30, Longitude=-71.35, ...
        TransmitterFrequency=freq, TransmitterPower=20, AntennaHeight=30)
    txsite(Name="Cell 2", Latitude=42.32, Longitude=-71.33, ...
        TransmitterFrequency=freq, TransmitterPower=20, AntennaHeight=30)
];

% SINR map -- each TX is signal source, others are interferers
sinr(txs, MaxRange=5000, Values=-5:2:20);
```

## Workflow 4: Line-of-Sight Analysis

```matlab
tx = txsite(Latitude=42.30, Longitude=-71.35, AntennaHeight=30);
rx = rxsite(Latitude=42.31, Longitude=-71.36, AntennaHeight=1.5);

% Check LOS (terrain-aware)
vis = los(tx, rx);
fprintf("Line of sight: %s\n", string(vis));

% Visualize LOS path on map
los(tx, rx);
```

## Workflow 5: Ray Tracing

Ray tracing computes multipath propagation including reflections and diffractions. Requires building or scene data.

### Geographic (Outdoor Urban)

```matlab
freq = 28e9;  % mmWave
tx = txsite(Name="5G BS", Latitude=42.3601, Longitude=-71.0589, ...
    TransmitterFrequency=freq, TransmitterPower=1, AntennaHeight=10);
rx = rxsite(Name="UE", Latitude=42.3605, Longitude=-71.0580, AntennaHeight=1.5);

pm = propagationModel("raytracing");
pm.Method = "sbr";                % shooting-and-bouncing rays
pm.MaxNumReflections = 3;
pm.MaxNumDiffractions = 1;
pm.AngularSeparation = "high";

raytrace(tx, rx, pm);
ss = sigstrength(rx, tx, pm);
coverage(tx, pm, MaxRange=500, SignalStrengths=[-60 -80 -100]);
```

### Ray Tracing Prop