Wireless AV Transmission with Frequency-Separated Error Correction
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Solution Overview
Problem
Current ATSC digital TV broadcast systems face challenges in providing reliable mobile reception of digital television signals, especially at vehicular speeds, due to difficulties in maintaining signal integrity under adverse conditions such as background noise and deep channel fading.
Innovation Solution
The system employs multiple layers of error correction coding and transmission diversity techniques, including complementary and overlapping error correction patterns transmitted at different times and frequencies, along with control information to associate and process audiovisual information effectively on mobile devices, ensuring robust signal reception and presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ATSC digital TV broadcast is used for mobile reception, then standard definition television can be transmitted, but reliable reception at vehicular speeds cannot be achieved due to signal integrity issues under adverse conditions
Solution Approach 1:
The patent segments the error correction process into multiple distinct layers: inner error correction coding applied to individual packets, outer error correction coding applied to groups of packets, and interleaving that distributes packets across time and frequency. This multi-layer segmentation provides progressive error protection that enables reliable mobile reception at vehicular speeds by addressing different types of signal degradation at each layer.
Solution Approach 2:
The patent applies error correction coding before transmission to cushion against anticipated signal degradation. Inner error correction codes are applied to each packet beforehand, and outer error correction codes are applied to groups of packets, creating a buffer that protects against noise and fading that will occur during mobile transmission at vehicular speeds.
2Reliability
If multiple error correction coding layers are applied to protect against noise and fading, then mobile reception reliability improves, but system complexity increases
Solution Approach 1:
The complexity is managed by segmenting the error correction function into distinct inner and outer coding layers with specialized algorithms for each. The inner code handles packet-level errors while the outer code handles group-level errors, allowing each layer to be optimized independently rather than requiring a single complex coding scheme.
Solution Approach 2:
The patent adds the dimension of time and frequency diversity through interleaving, distributing encoded packets across multiple time slots and frequency channels. This transforms the error protection from a single-dimensional process to a multi-dimensional approach, where errors must occur simultaneously across multiple dimensions to cause failure.
3Reliability
If error correction information is transmitted separately from audiovisual information, then error correction effectiveness improves, but transmission efficiency decreases due to additional packets and processing
Solution Approach 1:
The patent merges the inner error correction coded data with the original audiovisual packets to form augmented packets that contain both the original information and its error correction code. This combining allows the transmitted stream to carry both data and protection simultaneously, improving transmission efficiency while maintaining error correction effectiveness.
Solution Approach 2:
The patent uses interleaving to distribute packets across time and frequency dimensions, allowing error correction information to be transmitted in a structured manner that improves reliability without proportionally increasing overall transmission overhead. The time and frequency diversity enables efficient use of the broadcast channel.
Data Source
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AI summary
A method for transmitting audiovisual information in a wireless manner comprises: generating a first plurality of packets, wherein the first plurality of packets comprise first audiovisual information; generating a second plurality of packets, wherein the second plurality of packets comprise first error correction coding information for the first audiovisual information; generating control information, wherein the control information comprises commands for associating the first error correction coding information with the first audiovisual information; transmitting the first plurality of packets, the second plurality of packets, and the control information in a wireless manner. In order to reduce the susceptibility of the receiving device to specific reception issues, the first plurality of packets and the second plurality of packets are transmitted separated in frequency and the control information indicates that the first plurality of packets and the second plurality of packets are transmitted separated in frequency.