@mytec: iter3.2.1 start

backend/app/services/dominant_path_service.py

@@ -1,5 +1,6 @@
 import time
 import numpy as np
+from enum import Enum
 from typing import List, Tuple, Optional, Dict, Any, TYPE_CHECKING
 from dataclasses import dataclass
 from app.services.terrain_service import terrain_service
@@ -15,6 +16,38 @@ if TYPE_CHECKING:
     from app.services.spatial_index import SpatialIndex
 
 
+# ── Level of Detail (LOD) for dominant path calculations ──
+
+class LODLevel(Enum):
+    """Distance-based level of detail for dominant path analysis.
+
+    At long distances, building-level multipath contributes minimally
+    to path loss — macro propagation models suffice.
+    """
+    NONE = "none"              # Skip dominant path entirely
+    SIMPLIFIED = "simplified"  # Check only nearest few buildings
+    FULL = "full"              # Full calculation (current behavior)
+
+
+# LOD distance thresholds (meters)
+LOD_THRESHOLD_NONE = 3000        # >3km: skip dominant path
+LOD_THRESHOLD_SIMPLIFIED = 1500  # 1.5-3km: simplified mode
+
+# Simplified mode limits
+SIMPLIFIED_MAX_BUILDINGS = 5
+SIMPLIFIED_MAX_WALLS = 50
+
+
+def get_lod_level(distance_m: float) -> LODLevel:
+    """Determine LOD level based on TX-RX distance."""
+    if distance_m > LOD_THRESHOLD_NONE:
+        return LODLevel.NONE
+    elif distance_m > LOD_THRESHOLD_SIMPLIFIED:
+        return LODLevel.SIMPLIFIED
+    else:
+        return LODLevel.FULL
+
+
 @dataclass
 class RayPath:
     """Single ray path from TX to RX"""