Arbitrary Precision Multiple Description Coding for Wireless Channels
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Solution Overview
Problem
Conventional multiple description coding techniques are inefficient in adapting to variable channel conditions, leading to suboptimal bit rate and signal quality, and often result in wasted bandwidth or failure to receive signals due to fixed bit rate and quality settings, and require additional bandwidth for error detection and correction.
Innovation Solution
Arbitrary precision multiple description coding dynamically adjusts bit rate and signal quality based on channel conditions by using an encoder that processes signals with matrices selected according to available transmission resources, eliminating the need for quantization and additional channel coding, and allowing flexible subcarrier allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multiple description coding uses fixed quantization levels, then the bit rate and signal quality remain constant, but this leads to wasted bandwidth in good channels and failure to receive signals in poor channels
Solution Approach 1:
The patent implements dynamic adaptation by allowing the receiver to select from multiple pre-defined quantization matrices (different precision levels) based on actual channel conditions. The transmitter sends multiple descriptions encoded with different precision levels, and the receiver chooses the appropriate precision level dynamically, transforming the static fixed-quantization system into a dynamic adaptive one that matches channel conditions.
Solution Approach 2:
The patent changes the quantization parameter (precision level) based on channel conditions. Multiple quantization matrices with different precision levels are prepared in advance, and the appropriate one is selected according to channel quality. This parameter change allows the system to optimize between bit rate and signal quality dynamically, resolving the contradiction between adaptability and reliability.
2Reliability
If FEC and CRC codes are added for error detection and correction, then error handling capability improves, but bandwidth is wasted in channels without errors
Solution Approach 1:
The patent extracts the error handling function from separate FEC/CRC codes and integrates it into the multiple description coding structure itself. By encoding multiple descriptions with different precision levels, the system inherently provides error resilience without needing additional dedicated error correction codes, thus eliminating bandwidth waste while maintaining reliability.
Solution Approach 2:
The multiple description coding structure serves multiple functions simultaneously: it provides compression, enables adaptability to channel conditions, and offers inherent error resilience. The same encoded descriptions that enable adaptive precision selection also provide redundancy for error handling, making the system multi-functional and eliminating the need for separate error correction mechanisms.
3Ease of manufacture
If the number of transmission subcarriers must match the number of coefficients, then system implementation is simplified, but application flexibility is unduly limited
Solution Approach 1:
The patent segments the coefficient transmission into multiple descriptions with different precision levels. This segmentation allows flexible allocation of subcarriers to different description sets, enabling the system to adapt to various application requirements without requiring a strict one-to-one mapping between subcarriers and coefficients, thus enhancing application flexibility while maintaining implementation feasibility.
Data Source
AI summary
In one aspect, an encoder comprises arbitrary precision multiple description generation circuitry configured to produce multiple descriptions of a given signal by processing the signal using at least one matrix having a dimension which is selected as a function of a designated number of transmission resources, such as OFDM subcarriers or TDM time slots, that are allocated for transmission of the multiple descriptions. For example, the signal may comprise a vector x of dimension N and the arbitrary precision multiple description generation circuitry may be configured to generate M descriptions of the vector x where the value of M is selected to satisfy a particular one of three possible cases M=N, M>N and M<N depending on the number of subcarriers or time slots allocated for transmission of the multiple descriptions. Other aspects include a decoder, encoding and decoding methods, and associated computer program products.