ISDB-T Segment Detection Using Carrier Power Before TMCC Decode
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Solution Overview
Problem
Current ISDB-T receivers require approximately 408 symbols for segment type detection, leading to significant channel changeover time when switching between channels, necessitating a method for early detection of segment type in BPSK and DBPSK modulated carriers to minimize this delay.
Innovation Solution
The proposed receiver system includes a Frequency Domain Synchronization (FDS) block that calculates carrier powers using scattered pilots, TMCC, and Auxiliary Channel carriers to detect segment type, allowing channel estimation and correction before TMCC decoding, thereby reducing channel changeover time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TMCC carrier decoding is performed for segment type detection, then accurate segment type detection is achieved, but channel changeover time increases significantly
Solution Approach 1:
The patent performs preliminary channel estimation and signal analysis before TMCC decoding to detect segment type. By calculating carrier powers and performing initial channel characterization in advance, the system prepares necessary information that enables faster segment type detection without waiting for the full 408-symbol TMCC decoding process, thus reducing channel changeover time while maintaining detection accuracy
Solution Approach 2:
The patent extracts segment type information from channel characteristics and carrier power measurements rather than relying solely on TMCC decoding. By taking out the essential detection function from the lengthy decoding process and implementing it through independent channel estimation and power calculation, the system achieves rapid segment type identification that is not constrained by the 408-symbol decoding requirement
2Loss of time
If channel estimation is performed before TMCC decoding, then channel changeover time is reduced, but decoding robustness may be compromised
Solution Approach 1:
The patent performs preliminary channel estimation before TMCC decoding to establish initial channel characteristics. This preliminary action provides a head start for subsequent decoding operations, enabling the system to use the pre-estimated channel information as a foundation that improves decoding convergence and reliability rather than compromising it
Solution Approach 2:
The patent implements feedback mechanisms where the preliminary channel estimation results are continuously refined and updated during the TMCC decoding process. The initial channel estimates serve as feedback inputs that are adjusted and improved based on actual received signals, ensuring that the final decoding uses accurate, robust channel information while still benefiting from the time savings of early estimation
Data Source
AI summary
A receiver system for early detection of a segment type of an input signal based on BPSK and DBPSK modulated carriers is provided. The receiver system includes a tuner that converts the input signal into an intermediate frequency (IF) signal, a signal conditioning module that converts the IF signal into a baseband signal, a Frequency Domain Synchronization (FDS) block that detects the segment type of the input signal based on a carrier powers, a Transmission and Multiplexing Configuration Control (TMCC) decode block that performs a decoding operation on the received signal, a channel estimation block that estimates a channel and obtains a channel information. The TMCC decode block uses the channel information obtained from channel estimation block to correct a fast-frequency selective fading on the received signal before the decoding operation.