Dynamic Preamble Length Adjustment for DOCSIS Burst Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication systems in DOCSIS face challenges in efficiently adapting to distortion changes in the network, leading to data loss and increased overhead due to the need for longer preambles in both pre-equalization and post-equalization methods, particularly affecting VoIP and other data types.
Innovation Solution
An apparatus and method that dynamically adjust preamble lengths based on distortion characteristics, using a microprocessor to determine changes in network distortion and instruct adjustments in pre-equalization coefficients, allowing for shorter preambles in most data bursts while maintaining longer preambles only for Initial Maintenance and Station Maintenance bursts, thereby reducing overhead and quickly responding to distortion dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer preambles are used for all data types to allow post-equalizer convergence, then equalization reliability is improved, but overhead increases and productivity decreases
Solution Approach 1:
The patent applies local quality by differentiating preamble lengths based on data type characteristics. Initial Maintenance and Station Maintenance bursts receive long preambles (256 symbols) to ensure equalizer convergence, while Short Data, Long Data, Advanced Short, Advanced Long, and UGS bursts receive short preambles (64 symbols) to minimize overhead. This selective approach ensures adequate equalization for maintenance traffic while optimizing throughput for data traffic.
Solution Approach 2:
The patent implements dynamics by making preamble length adaptive rather than static. The CMTS dynamically selects preamble length based on the IUC value of each burst, allowing the system to optimize between convergence reliability and transmission efficiency in real-time according to traffic requirements.
2Productivity
If pre-equalization is used to reduce overhead, then productivity is improved, but adaptability to distortion changes deteriorates
Solution Approach 1:
The patent applies preliminary action by having the CMTS pre-compute equalizer coefficients during Station Maintenance bursts using long preambles, then store these coefficients for later use. This allows the system to prepare equalization parameters in advance during maintenance intervals, enabling efficient pre-equalization during data bursts without requiring real-time adaptation.
Solution Approach 2:
The patent implements feedback by monitoring post-equalizer convergence status and distortion changes during data transmission. When distortion changes are detected or convergence is inadequate, the system triggers a Station Maintenance burst to re-compute and update equalizer coefficients, ensuring continuous adaptability to network conditions.
3Adaptability or versatility
If post-equalization is used to adapt to distortion changes, then adaptability is improved, but overhead increases due to longer preambles for all bursts
Solution Approach 1:
The patent applies local quality by providing enhanced equalization resources (long preambles) only where needed for Station Maintenance bursts, while using minimal preambles for data bursts. This selective resource allocation ensures distortion compensation capability is maintained for maintenance traffic while minimizing overhead for data traffic.
Solution Approach 2:
The patent applies preliminary action by pre-computing equalizer coefficients during Station Maintenance bursts and storing them for subsequent use. This allows the system to perform the computationally intensive equalization adaptation during maintenance intervals rather than during data transmission, reducing real-time overhead while maintaining adaptability.
Data Source
AI summary
Preamble length of burst communication signals dynamically changed to compensate in changes to linear distortion of a communication channel. Pre-equalization coefficients are provided to network element which pre-equalize communications with the CMTS. Long preamble lengths are used for a select few communications while short preamble lengths are used for the rest of the communication signals. When change in distortion characteristics is detected, a station maintenance is performed on the affected network element and new pre-equalization coefficients are determined and provided to the network element. Alternatively, all communications may be provided with long preamble lengths and communications may continue while the CMTS determines new pre-equalization coefficients.