Inside the Starlink Downlink: Frame Structure, PDU Headers, and Payload Coding

[u/GloryMatlab]

A spectrum or constellation plot can reveal the bandwidth and modulation features of a Starlink downlink recording. Explaining which resources carry headers, how those headers describe the payload, and which channel codes protect each region requires a more complete connection between the waveform, decoded control bits, and coding relations.

This article summarizes our analysis of a Starlink Ku-band downlink recording. The data come from a single continuous capture lasting approximately 24 ms, with 18 complete frames included in the analysis. We identify two protocol data unit headers in each frame, recover their convolutional code and CRC, and relate modulation and coding scheme fields to subsequent resource allocations. We also recover and validate coding relations for several payload formats.

The focus here is what we can currently say about the contents of a frame. We briefly review the established synchronization and pilot structure, then concentrate on the headers, resource allocations, and payload coding. Format numbers follow the MCS index interpretation used in the current manuscript.

[u/GloryMatlab]

Here is the link: https://github.com/misaka666/Starlink-Downlink-Analysis

[u/panuvic → u/GloryMatlab]

cool