Passive Precision Time over BLE: V14 Boundary Clocks, Causal Timestamping, and Prospective One-Relay Validation

Overview

The V14 paper documents the path to the protocol revision and its one-relay PPS-shadow experiment. A T096 relay regenerates timing for another receiver; a separately captured pulse-per-second (PPS) edge evaluates the clock map that receiver had already published. The witness does not train the BLE clock.

What this paper covers

• The distinction between a regenerated timing train and forwarding an original packet.
• How an independent PPS witness evaluates an already-published map.
• Why frozen calibration, unavailable observations and nominal boundaries belong with the reported error.

Research scope

The 12 October population has 62.504 ns RMS including bias, with 436 usable comparisons out of 602 nominal boundaries. It is historical one-intermediary evidence, not calibrated absolute UTC, output-pin accuracy or qualification of current firmware and additional hops.

Read it in context

Read the online relay record alongside the paper to keep the signed bias, tail statistics, calibration and observation-gap accounting together. The original 2 October direct experiments remain a separate archive.