OFDM Bootstrap Signal Detection via Cyclic Shift Correlation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for an efficient and cost-effective technique to detect the bootstrap signal in Orthogonal Frequency Division Multiplexed (OFDM) systems, particularly in broadcast television systems like ATSC 3.0, where the bootstrap signal is robust but expensive in terms of physical resources due to its design for robustness and universality.
Innovation Solution
A receiver is designed to detect and recover payload data using a bootstrap processor that estimates the channel transfer function from bootstrap OFDM symbols, convolves a signature sequence with the channel impulse response, and uses cross-correlation to identify the cyclic shift of the signature sequence, allowing for efficient decoding with a single inverse Fourier transform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bootstrap signal is designed to be robust and universally detectable, then detection reliability is improved, but the physical resources required for transmission increase
Solution Approach 1:
The patent extracts only the essential information needed for system discovery from the bootstrap signal, separating it from the full service information. The bootstrap processor identifies and processes only the critical signaling data required for initial detection and system entry, while excluding redundant or non-essential information, thereby reducing the physical resources needed for transmission while maintaining detection reliability.
Solution Approach 2:
The patent segments the information transmission into two distinct parts: the bootstrap signal containing minimal essential system discovery information, and the subsequent full service information. This segmentation allows the bootstrap portion to be transmitted with reduced resource requirements while still ensuring reliable detection, as it carries only the most critical data needed for initial system access.
2Productivity
If the bootstrap signal carries minimal information for system discovery, then resource efficiency is improved, but the complexity of detecting and decoding the signal increases
Solution Approach 1:
The patent implements preliminary action by providing the receiver with prior knowledge of the bootstrap signal structure, including the exact format, location, and encoding scheme of the signaling data. The receiver is pre-configured with the bootstrap processor that knows how to identify and decode the cyclic shift patterns, thereby reducing the actual detection complexity during operation despite the condensed information format.
Solution Approach 2:
The patent utilizes parameter changes in the form of cyclic shifts of a known sequence to encode signaling information. By varying the cyclic shift parameter, multiple bits of information can be conveyed through a single known sequence, achieving high information density without requiring complex modulation schemes, thus balancing resource efficiency with detection complexity.
3Loss of information
If cyclic shift detection is used to convey signaling information, then information density is improved, but the difficulty of detecting and measuring the signal increases
Solution Approach 1:
The patent employs copying by using a known reference sequence that is cyclically shifted to convey information. The receiver has an identical copy of the original sequence stored, and by comparing the received signal against this known copy, it can easily detect the cyclic shift amount. This copying approach allows high information density through cyclic shifts while keeping detection straightforward through simple correlation with the known reference.
Data Source
AI summary
A receiver for detecting and recovering payload data from a received signal comprises a radio frequency demodulation circuit configured to detect the received signal. The received signal has been formed and transmitted by a transmitter to carry the payload data as Orthogonal Frequency Division Multiplexed (OFDM) symbols in one or more of a plurality of time divided frames, each frame including a preamble including a plurality of bootstrap OFDM symbols. One or more of the bootstrap OFDM symbols of the preamble carrying signalling data represented as a relative cyclic shift of a signature sequence which has been combined with the one or more of the bootstrap OFDM symbols. A bootstrap processor is configured to detect the signalling data from the bootstrap OFDM symbols using an estimate of the channel transfer function determined from one or more of the bootstrap OFDM symbols, and a demodulator circuit is configured to recover the payload data from the payload OFDM symbols using the signalling data. The bootstrap processor comprises a channel shaper, which is configured to convolve a time domain copy of the signature sequence with the estimate of the channel impulse response to generate a channel shaped signature sequence, a cross-correlator and a cyclic shift detector. A cross-correlator is configured to cross-correlate the useful part of each of the one or more bootstrap OFDM symbols with the channel shaped copy of the signature sequence, and the cyclic shift detector is configured to estimate the signalling data conveyed by each of the one or more bootstrap OFDM symbols by detecting a cyclic shift of the signature sequence present in each of the one or more bootstrap OFDM symbols from a peak of the samples representing a result of the cross-correlation. Accordingly the signalling data can be detected by identifying the cyclic shift of the signature sequence by cross-correlating the signature sequence with the bootstrap OFDM symbols carrying the signature sequence in the time domain, which can provide a more efficient implementation.