Baseband Repeater for Mobile TV Signal Integrity
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Solution Overview
Problem
Current digital transmission repeaters either lose mobile/handheld data when decoding signals or are limited in the number of repeaters due to noise and multipath degradation in mobile environments, as they are not robust enough to handle doppler shifts and multipath radio interference.
Innovation Solution
A repeater system that includes a receiver for demodulating VSB television signals, a processor with frame registration, trellis coding, and upconversion capabilities to identify and maintain the structure of mobile/handheld data frames, allowing for robust signal retransmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a repeater decodes the received signal to baseband and recodes the baseband data, then the signal quality is improved, but mobile/handheld data is lost
Solution Approach 1:
The patent segments the received signal into main data and mobile/handheld data components. The main data is decoded to baseband while the mobile/handheld data is extracted and preserved separately, then both are recoded together to maintain signal quality and preserve mobile data integrity
Solution Approach 2:
The patent introduces an intermediary processing stage that separates mobile/handheld data from the main data stream before baseband decoding. This intermediary step allows the mobile data to be protected from loss while still enabling the signal quality improvements from baseband recoding
2Stability of the object's composition
If a repeater steps down the received signal to IF for filtering and steps up the signal at IF to RF, then the signal structure is maintained, but noise and multipath degradation accumulate
Solution Approach 1:
The patent replaces the traditional RF/IF signal processing chain with a baseband digital signal processing approach. By converting the signal to baseband, performing digital filtering and processing, then recoding, the system achieves better noise rejection and multipath mitigation while maintaining signal structure through digital rather than analog processing
3Reliability
If additional channel coding mechanisms are introduced to protect against doppler shift and multipath interference, then mobile reception robustness is improved, but system complexity increases
Solution Approach 1:
The patent implements a universal baseband processing framework that handles both main data and mobile/handheld data through the same decoding and recoding mechanisms. This multi-functional approach provides robust protection against doppler shift and multipath interference for all data types without requiring separate complex coding systems
Solution Approach 2:
The patent changes the processing parameters from RF/IF domain to baseband domain, enabling the use of advanced channel coding and decoding techniques that are optimized for mobile reception. This parameter change allows efficient implementation of robust coding mechanisms that protect against doppler shift and multipath effects
Data Source
AI summary
A repeater receives an input signal containing mobile/handheld (M/H) data received in an M/H frame equivalent in size to 20 VSB data frames. Each VSB frame contains an odd VSB field and an even VSB field, and each of the VSB fields includes one field sync segment and 312 data segments. The M/H frame includes main data and M/H data, and the M/H data has more robust coding than the main data. The received input signal is demodulated to produce an MPEG transport steam. Frame registration is used to find data and field syncs in the MPEG transport steam. The trellis encoder is reset prior to M/H training data in to the mobile data stream. The data is VSB modulated, the field syncs are added to the modulated data to reconstruct the M/H frame, and the M/H frame upconverted to an RF output signal, which is retransmitted.