US 9253428

US Patent 9253428: Concise Summary

Title: Broadcasting system with digital television signals and metadata that modulate respective sets of OFDM carriers

Assignee: CERINET USA Inc (Current Assignee, as of 2021-12-10). The original assignee was listed as "Individual."

Inventors: Arthur Webb Allison, III; Allen LeRoy Limberg

Filing Date: 2015-05-20

Issue Date: 2016-02-02

Abstract: The patent describes a digital television (DTV) broadcasting system utilizing coded orthogonal frequency-division multiplexed (COFDM) modulation. This system is designed to modulate mid-band OFDM carriers with metadata, which includes synchronization signals and transmission-mode signals. Concurrently, DTV signals modulate other OFDM carriers positioned in frequency spectrum portions both below and above these mid-band carriers. A key aspect is the use of the mid-band OFDM carriers to signal the introduction of new broadcast services. This signaling is achieved by modulating these carriers with specific "signature sequences," which are comprised of Zadoff-Chu sequences and repetitive pseudo-random sequences that are scrambled by a Zadoff-Chu sequence.

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim outlines a broadcasting system for digital television (DTV) signals that uses COFDM (coded orthogonal frequency-division multiplexed) carrier waves. The system comprises a DTV signal generator that modulates a first set of COFDM carriers with DTV signals, where these carriers are located in frequency bands both below and above the central portion of a radio-frequency (RF) channel. Additionally, a metadata generator modulates a second, distinct set of COFDM carriers, located specifically in the central portion of the RF channel, with metadata that includes synchronization and transmission-mode information. A distinctive feature is that these central, metadata-carrying carriers are used to signal the introduction of a new broadcast service, different from the current one. This signaling is accomplished by modulating these central carriers with unique "signature sequences," each composed of Zadoff-Chu sequences and pseudo-random noise (PN) sequences scrambled by a Zadoff-Chu sequence.

• Independent Claim 13: This claim details a DTV receiver designed to operate with the broadcasting system described in Claim 1. The receiver includes a front-end tuner for converting incoming RF COFDM signals into digitized baseband samples, and a Discrete Fourier Transform (DFT) computer for demodulating the COFDM carriers from these samples to extract DTV signals and metadata. A QAM de-mapper then processes the demodulated central COFDM carriers to recover the baseband metadata signals. Crucially, a controller within the receiver is configured to receive these metadata signals and identify the presence of a new broadcast service by detecting the specific signature sequences (made up of Zadoff-Chu sequences and scrambled pseudo-random sequences) that modulate the central COFDM carriers.

• Independent Claim 14: This claim describes a method for broadcasting digital information. The method involves generating digital television signals and using them to modulate a first set of OFDM carrier waves located in frequency bands both below and above the center of a radio-frequency (RF) channel. It also involves generating metadata, including synchronization and transmission-mode signals, and using this metadata to modulate a second, different set of OFDM carrier waves, which are positioned in the central part of the RF channel. These modulated first and second sets of OFDM carrier waves are then transmitted. The method further specifies that the central OFDM carriers, carrying metadata, are specifically modulated with signature sequences (derived from Zadoff-Chu sequences and pseudo-random sequences scrambled by a Zadoff-Chu sequence) to signal the introduction of a new broadcast service.

CAFC 2026 Dockets:
A search of the U.S. Court of Appeals for the Federal Circuit (CAFC) dockets for 2026 concerning patent number 9253428 did not identify any specific case filings or ongoing litigation as of April 26, 2026. The search results provided general information about the CAFC. Therefore, no authoritative information on active litigation for this patent was found for the specified period.