Extends R6.2 from 2D ellipse to 3D ellipsoid + 3D target zones (bed at
z=0.3-0.6, chair at z=0.5-1.2, standing at z=1.0-1.7 in a 5x5x2.5 m
room).
Counter-intuitive headline:
| Strategy | Coverage |
|-------------------------------------------|---------:|
| Desk-height (0.8 m walls) | 22.2% |
| Wall-mount (1.5 m walls) | 17.4% |
| Ceiling-only (2.5 m grid) | 0.0% | <-- FAILS
| Mixed walls + ceiling | 25.7% | <-- BEST
Ceiling-only fails because both antennas at 2.5 m create a Fresnel
ellipsoid sitting AT ceiling height (2.1-2.9 m vertically). Target
zones at 0.3-1.7 m are below the envelope by 0.4-2.0 m. The 39 cm
transverse radius is symmetric around LOS, so a flat horizontal link
at any height misses targets at any OTHER height.
This is the 3D version of R6.1's on-LOS-degeneracy finding. A
horizontal link at any single height has its envelope concentrated
at that height.
Why mixed wins: best placement is Tx (5.0, 4.0, 0.8) + Rx (0.0, 4.0, 1.5).
The diagonal-in-z link tilts the ellipsoid through multiple elevations.
Covers chair AND standing AND bed simultaneously.
Vertical link diversity is the 3D insight 2D analysis missed.
Installation-guide updates:
- Single pair: one low (0.8 m) + one high (1.5 m), opposite walls
- 4-anchor: 2x low corners + 2x high opposite corners
- 5-anchor knee: mix 0.8 / 1.5 / one ceiling
- Bed-only: both LOW
- Standing-only: both HIGH
- NEVER: both ceiling without a low anchor
Coverage numbers are lower than R6.2's 2D 51% because 3D volumetric
coverage is inherently lower than 2D area coverage -- honest 3D physics.
Composes:
- R6.2 (2D) -- incomplete; height matters as much as horizontal
- R6.2.2 (N-anchor) -- N=5 knee should distribute across heights
- R6.1 (multi-scatterer) -- needs 3D body model for proper composition
- R14 V1/V2/V3 -- each vertical needs height-recipe
- ADR-029 -- placement is (x, y, z), not (x, y)
- R12 PABS -- detects intruders standing/sitting/lying with mixed heights
Honest scope: 3-zone discrete approximation, single-pair only, no
furniture occlusion, 0.1 m resolution, greedy search.
Coordination: ticks/tick-21.md, no PROGRESS.md edit.
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