Overlapping OFDMA Channels for Mid-Split and High-Split Coexistence
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Solution Overview
Problem
Cable operators face challenges in managing mixed deployments of high-split and mid-split cable modems due to frequency constraints, leading to capacity loss and interference, as existing systems lack efficient methods to utilize the full upstream spectrum without additional hardware or software modifications.
Innovation Solution
A CMTS-based solution that configures overlapping OFDMA channels by creating a 'Long Channel' for high-split modems and a 'Short Channel' for mid-split modems, using identical UCDs and MAPs below a predetermined frequency, allowing a single burst receiver to manage both types without hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-split frequency plan is implemented to increase upstream capacity, then bandwidth for uploads and video conferencing is improved, but legacy mid-split cable modems cannot operate above their frequency limit causing interference and capacity loss
Solution Approach 1:
The patent segments the upstream channel into two distinct channels: a first upstream channel for high-split cable modems and a second upstream channel for mid-split cable modems. This segmentation allows high-split modems to utilize higher frequencies for increased capacity while mid-split modems operate on lower frequencies without causing interference, resolving the contradiction between improving upstream capacity and preventing interference.
Solution Approach 2:
The patent applies local quality by assigning different frequency ranges to different cable modem types. The first upstream channel uses higher frequencies (above the split frequency) for high-split modems, while the second upstream channel uses lower frequencies (at or below the split frequency) for mid-split modems. This localized frequency allocation optimizes performance for each device type while preventing harmful interference.
2Adaptability or versatility
If frequency plans are made complex to support legacy devices, then compatibility is improved, but system complexity increases and capacity is lost
Solution Approach 1:
The patent segments the frequency spectrum into dedicated bands for different cable modem capabilities. By creating separate first and second upstream channels with defined frequency ranges, the system achieves compatibility with both high-split and mid-split modems without requiring complex frequency planning or dynamic adjustment, thus improving compatibility while maintaining simplicity.
Solution Approach 2:
The CMTS is configured to support both high-split and mid-split cable modems through a universal design that incorporates multiple upstream channels. This multi-functional approach allows a single CMTS to serve diverse device types without requiring separate systems, thereby improving adaptability while avoiding the complexity that would arise from trying to accommodate all devices on a single frequency plan.
3Productivity
If additional hardware or software modifications are made to support high-split frequencies, then upstream capacity is improved, but deployment cost and complexity increase
Solution Approach 1:
The patent segments the upstream spectrum to allow high-split cable modems to operate on a first upstream channel above the split frequency without requiring modifications to existing mid-split modems. The mid-split modems continue to operate on the second upstream channel at or below the split frequency using their existing hardware. This segmentation enables upstream capacity improvement through high-split frequencies without mandating hardware or software modifications to legacy devices, thereby reducing deployment complexity.
Solution Approach 2:
The patent extracts the high-frequency operation requirement from the general upstream channel and creates a separate first upstream channel specifically for high-split cable modems. This extraction allows high-split modems to utilize the additional bandwidth above the split frequency without forcing modifications onto mid-split modems, thus improving upstream capacity while maintaining ease of deployment for legacy devices.
Data Source
AI summary
In some aspects, the disclosure is directed to methods and systems for overlapping orthogonal frequency-division multiple-access (OFDMA) channels for coexistence of devices and legacy devices, including DOCSIS 3.1 mid-split and high-split cable modems (CMs). Described are systems and methods for providing a CMTS with capability for managing overlapping OFDMA channels to support mid-split and high-split CMs, without modification to legacy CMs.