Tone Ordering for Discrete Multi-Tone Systems
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Solution Overview
Problem
Newer DMT technologies like VDSL, which use a large number of tones, face increased memory requirements and processing time due to tone ordering tables, and grouping consecutive tones can lead to decreased decoder performance from correlated noise.
Innovation Solution
Divide sub-channels into groups and select them in non-sequential order, assigning data bits accordingly, allowing for efficient tone ordering that distributes adjacent bits throughout the frequency band, reducing storage needs and maintaining decoder performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If consecutive tones are grouped together for resource efficiency, then memory storage requirements are reduced, but decoder performance decreases due to correlated noise affecting adjacent bits
Solution Approach 1:
The patent segments the tone-to-bit mapping into multiple separate tables (first tone ordering table and second tone ordering table) instead of using a single comprehensive table. This segmentation allows the system to reduce memory storage by dividing the mapping information into manageable chunks while maintaining the ability to distribute adjacent bits across non-adjacent tones through selective table usage, thereby preventing correlated noise from affecting consecutive bits in the decoded stream.
Solution Approach 2:
The patent applies preliminary action by pre-organizing tone mappings into multiple structured tables with specific patterns before transmission. The transmitter and receiver both store these pre-configured tone ordering tables, which are designed in advance to distribute adjacent bits across non-adjacent tones. This preliminary organization enables efficient memory usage while ensuring that when tones are grouped, the bit assignment pattern prevents correlated noise degradation.
2Productivity
If the number of tones is increased for higher data capacity, then data transmission capability improves, but memory requirements and processing time increase proportionally
Solution Approach 1:
The patent divides the tone ordering information into multiple separate tables rather than storing one large comprehensive table. For systems with many tones (e.g., VDSL with 4096 tones), this segmentation allows the memory to store multiple smaller tables with specific patterns, reducing the overall memory footprint while still supporting high data transmission capacity through efficient bit-to-tone mapping.
Solution Approach 2:
The patent uses partial action by implementing multiple tone ordering tables with different mapping patterns rather than a single exhaustive table. The system can selectively use different tables or combinations of tables depending on the transmission conditions, achieving efficient memory utilization while maintaining the capability to handle large numbers of tones for high data capacity transmissions.
3Reliability
If tone ordering tables are stored in both transmitter and receiver, then correct bit-to-tone mapping is achieved, but device complexity and memory resources are consumed
Solution Approach 1:
The patent segments the tone ordering data into multiple smaller tables that are stored in both transmitter and receiver. This segmentation reduces the memory burden on each device compared to storing a single large comprehensive table, while still ensuring accurate bit-to-tone mapping through the coordinated use of these segmented tables at both ends of the communication link.
Data Source
AI summary
The present disclosure describes a method and system of tone ordering for discrete multi-tone (DMT) systems with tone grouping. Some illustrative embodiments may include a method, comprising, dividing a plurality of sub-channels within a discrete multi-tone symbol into a plurality of groups, selecting each sub-channel of the plurality of sub-channels in non-sequential sub-channel order from the plurality of groups, and assigning data bits in bit order to each sub-channel in the order in which each sub-channel is selected. Each group comprises an equal number of sub-channels, and each sub-channel comprises a frequency bin with a unique center frequency.