A/321, “System Discovery and Signaling”Approved: 3 April 2024

This document describes the system discovery and signaling architecture for the ATSC 3.0 physical layer. Broadcasters anticipate providing multiple wireless-based services, in addition to conventional broadcast television in the future. Such services may be time-multiplexed together within a single RF channel. The bootstrap provides a universal entry point into a broadcast waveform. The bootstrap employs a fixed configuration (e.g., sampling rate, signal bandwidth, subcarrier spacing, time-domain structure) known to all receiver devices and carries information to enable processing and decoding the wireless service associated with a detected bootstrap. This capability ensures that broadcast spectrum can be adapted to carry new services and/or waveforms for the public interest to continue to be served in the future.

Download current version: A/321:2024-04, “System Discovery and Signaling”, 3 April 2024. This version of the Standard is normatively referenced in A/300:2024-04.

Previous Versions

There are multiple versions of this document. Please be sure to download the desired version. For amendments, the text includes a list of changes, the rationale for the changes, and compatibility considerations.

Download A/321:2016, “System Discovery and Signaling”, approved 23 March 2016. This Standard is normatively referenced by A/300:2019, A/300:2020, and A/300:2021.

A/321:2016, dated 23 March 2016, was approved and adopted by reference into the U.S. FCC Rules 47 CFR § 73.682. In subsequent versions of A/321, normative and informative references to other ATSC standards and recommended practices have been updated to reference current version documents. No other changes have been made.

Download A/321:2022-03, “System Discovery and Signaling”, 31 March 2022. This version of the Standard is normatively referenced in A/300:2022-04.

Download A/321:2023-03, “System Discovery and Signaling”, 31 March 2022. This version of the Standard is normatively referenced in A/300:2023-03.