DSL Transceiver Bit Table Switching for Crosstalk Noise Adaptation
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Solution Overview
Problem
Digital subscriber line technologies face significant challenges due to crosstalk noise, which can lead to increased bit error rates and service interruptions, especially in VDSL2, where higher frequencies and shorter line lengths exacerbate the issue, and existing solutions either waste bandwidth or have slow response times.
Innovation Solution
A method and system that dynamically adapt transmission rates based on noise changes by pre-calculating and storing bit and gain tables, allowing for a fast switch to predetermined tables when noise exceeds a threshold, eliminating the need for real-time data exchange and ensuring high reliability and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target Signal to Noise Ratio margin is increased to avoid re-training caused by crosstalk, then the reliability of communication is improved, but the transmission rate is reduced
Solution Approach 1:
The patent implements dynamic rate adaptation by continuously monitoring the Signal to Noise Ratio margin and adjusting the transmission rate accordingly. When the SNR margin exceeds a threshold indicating crosstalk conditions, the system reduces the transmission rate to prevent link failure, and when the margin is sufficient, it increases the rate to maximize throughput. This dynamic adjustment resolves the contradiction by making the transmission rate adaptive rather than fixed.
Solution Approach 2:
The system employs feedback mechanisms by monitoring communication quality parameters (SNR margin, bit error rate) and using this information to adjust transmission parameters. The receiver feeds back quality information to the transmitter, which then adapts the transmission rate to maintain reliable communication while optimizing throughput, thus resolving the contradiction between reliability and transmission rate.
2Productivity
If seamless rate adaptation is implemented to adjust bit allocation according to noise distribution, then the transmission capacity is optimized, but the response speed is reduced due to large data exchange requirements
Solution Approach 1:
The patent pre-calculates and stores multiple rate adaptation tables (bit allocation tables and gain tables) corresponding to different noise conditions before actual communication begins. When crosstalk occurs and rate adaptation is needed, the system can immediately switch to a pre-computed table matching the current noise level, avoiding the time-consuming process of real-time calculation and large data exchanges, thus resolving the contradiction between optimization capability and response speed.
3Ease of operation
If a flat signal to noise ratio margin is reserved for all sub-channels to simplify implementation, then the ease of operation is improved, but the transmission capacity is wasted in frequency bands with low crosstalk influence
Solution Approach 1:
The patent implements non-uniform rate adaptation where different SNR margins are applied to different sub-channels based on their specific crosstalk characteristics. Instead of using a flat margin for all frequencies, the system calculates and applies customized margin values for each sub-channel according to the actual noise distribution, thereby maintaining implementation simplicity while avoiding capacity waste in low-crosstalk frequency bands.
Data Source
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AI summary
A method and device for performing communication in digital subscriber line technology. When a communication performance parameter reaches or exceeds a predetermined value, a first transceiver transmits a switch request message to a second transceiver, so that the second transceiver switches to a bit table; the first transceiver perform a synchronous switch of the bit table through a synchronous signal from the second transceiver. The bit table on the second transceiver is calculated by the first transceiver based on an experiential bit table calculating parameter that is a bit number reduced from a bit number calculated according to an actual noise; and the experiential bit table calculating parameter is received by the first transceiver from the second transceiver. There is no need of interchanging the bit table and the gain table when using this method.