Overlapping OFDMA Channels for Mid-Split and High-Split Cable Modems
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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 range limitations, leading to capacity loss and interference, as existing systems struggle to efficiently utilize the entire upstream spectrum without additional hardware costs.
Innovation Solution
A CMTS system configures channel allocations using a 'Long Channel' and a 'Short Channel' for high-split and mid-split cable modems, respectively, with identical parameters below a predetermined frequency, allowing a single receiver to manage both types without additional hardware, by generating separate UCDs and MAPs with different identifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the upstream spectrum is split into different frequency ranges to support both high-split and mid-split cable modems, then compatibility with legacy devices is improved, but the frequency plan becomes complex and capacity is lost
Solution Approach 1:
The upstream spectrum is segmented into two distinct channel sets: a first set of channel allocations for high-split cable modems and a second set of channel allocations for mid-split cable modems. This segmentation allows each device type to operate on its designated channels without interference, resolving the complexity issue while maintaining compatibility.
Solution Approach 2:
Different quality attributes are assigned to different channel sets based on device capabilities. High-split cable modems receive access to higher frequency channels with greater bandwidth, while mid-split cable modems are assigned lower frequency channels. This local differentiation optimizes performance for each device type without requiring a completely separate frequency plan.
2Productivity
If separate channel allocations are created for high-split and mid-split cable modems, then capacity utilization is improved, but additional hardware and complexity are required
Solution Approach 1:
The CMTS receiver is designed with multi-functionality to handle both high-split and mid-split cable modems through a single receiver instance. The system universally manages both channel sets using the same receiver infrastructure, eliminating the need for separate hardware receivers for each device type while maintaining full capacity utilization.
Solution Approach 2:
The system dynamically allocates channels based on device capability rather than requiring static hardware configurations. The CMTS can flexibly assign either the first or second set of channel allocations to different cable modems based on their operational characteristics, allowing dynamic adaptation without additional hardware.
3Device complexity
If a single receiver is used for both high-split and mid-split cable modems, then hardware costs are reduced, but interference between channel sets may occur
Solution Approach 1:
The receiver processes signals from both channel sets by maintaining separate reception paths in the signal processing domain. The first set of channel allocations and second set of channel allocations are processed as distinct signal streams, preventing interference between them while using a single physical receiver hardware instance.
Data Source
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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.