OFDM Profile Selection via MER Margin Averaging
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Solution Overview
Problem
Current DOCSIS 3.1 specification methods for selecting OFDM profiles result in inaccurate Code Error Rate (CER) estimation, leading to inefficient communications and decreased customer satisfaction due to incorrect profile selection.
Innovation Solution
A method that calculates a score value for each profile based on the Mean Error Ratio (MER) margin vector, employing linear domain averaging and hysteresis checks to select the optimal profile, ensuring low data error rates and increased data capacity by choosing profiles with the highest capacity and lowest error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the DOCSIS 3.1 specification algorithm is used to select OFDM profiles, then profile selection can be automated, but the Code Error Rate estimation becomes inaccurate
Solution Approach 1:
The patent changes the selection criterion from SNR-based to CER-based. Instead of using the DOCSIS 3.1 specification's SNR algorithm, the invention calculates Code Error Rate (CER) for each profile and selects the profile with the lowest CER. This parameter change from SNR to CER directly addresses the inaccuracy in CER estimation while maintaining automation.
Solution Approach 2:
The patent implements a feedback mechanism where the system monitors actual communication performance and uses this information to refine profile selection. By calculating CER based on actual received signals and comparing it across profiles, the system creates a feedback loop that continuously optimizes profile selection accuracy.
2Ease of operation
If profiles are selected based on SNR alone, then the selection process is simple, but communication efficiency decreases due to incorrect profile selection
Solution Approach 1:
The patent replaces the SNR parameter with CER parameter for profile selection. While this adds a calculation step, it significantly improves communication efficiency by selecting profiles that actually minimize error rates rather than just maximizing signal strength. The CER calculation is based on measurable signal parameters, keeping the process relatively simple while dramatically improving outcomes.
3Productivity
If higher capacity profiles are selected, then data throughput increases, but error rates increase leading to retransmissions
Solution Approach 1:
The patent changes the selection metric from capacity-only to CER-based selection. Instead of automatically choosing the highest capacity profile, the system calculates CER for each profile and selects the one with the lowest error rate. This may sometimes mean choosing a lower capacity profile that is more reliable for current channel conditions, thereby reducing retransmissions and improving overall effective throughput.
Solution Approach 2:
The patent uses actual signal measurement feedback to determine the optimal trade-off between capacity and reliability. By measuring CER on actual received signals and using this feedback for profile selection, the system adapts to current channel conditions and selects profiles that optimize the balance between throughput and error rates rather than always maximizing capacity.
Data Source
AI summary
Assigning an appropriate modulation profile for an orthogonal frequency-division multiplexing (OFDM) channel. The current modulation profile assigned to a specific OFDM modem for communicating over a specific OFDM channel is examined to determine whether to consider reassigning the specific OFDM modem to a different modulation profile. Only upon determining consideration should be given, an assessment is made as to which modulation profile, of a set of candidate modulation profiles available to that OFDM modem for communicating over the specific OFDM channel, should be assigned to the specific OFDM modem using linear domain averaging over the OFDM subcarriers of the ratios between a Mean Error Rate (MER) threshold per subcarrier for the specific OFDM modem and the MER reported by the specific OFDM modem per subcarrier. A new modulation profile is assigned to the specific modem based on the assessment.