Indoor/Dense Urban Neutral Host

Martin James
2 days ago
2 min read

Designing timing resilience when GNSS is weak even near windows

Sector: Dense urban in-building neutral host (multi-tenant property)

Challenge: GNSS multipath/attenuation made reception unreliable; roof route complex and slow

Forward-looking requirement: Architecture ready to adopt indoor LEO PNT when available

Starting position

The building had:

A shared comms room in the basement
Risers and fibre to each floor’s radio zones
Limited access to the roof and strict façade rules

Even “window GNSS” was unreliable due to urban canyon effects.

Timebeat deployment strategy

1) Near-term: engineered PTP as the primary distribution method

Timebeat deployed a timing appliance in the comms room. Absolute time was obtained via the best available reference (initially GNSS from a nearby accessible point / managed feed), and PTP was distributed internally with aggressive stability controls for PDV and asymmetry.

2) Resilience: holdover + redundancy philosophy

Because absolute reference could be intermittent, the system was designed to:

ride through short reference interruptions via disciplined holdover
alarm clearly when reference quality degraded
maintain stable local time so the RAN didn’t “flap”

3) Future-ready: plan for LEO indoor timing input

The customer wanted a path away from roof GNSS entirely.

Timebeat positioned the design to accept LEO-based PNT inputs as they mature:

Xona Pulsar is positioned as a LEO PNT service focused on robust timing/positioning.
Iridium STL is marketed as a resilient time/location service with strong signals that can penetrate indoors, reducing antenna installation friction.

Result (operational outcomes)

The neutral host deployment proceeded without waiting for roof work.
The building owner accepted a clean indoor infrastructure model.
The timing architecture was positioned for an upgrade path: swap/augment the timing input when LEO reception becomes part of the customer’s standard.

Why this matters

This is the future of neutral host: timing designed for indoor reality, not retrofitted from macro-site assumptions.