Multicast IUC3 Regions for Cable Modem Timing Offset Adjustment
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Solution Overview
Problem
Cable modems in low power mode lack a mechanism to quickly reacquire timing offset when waking up before the end of their scheduled sleep cycle, leading to inefficiencies in upstream data transmission due to the lack of suitable timing adjustment mechanisms.
Innovation Solution
The introduction of reduced multicast IUC3 regions allows cable modems to adjust their timing offset quickly upon waking by allocating smaller, more frequent timing adjustment opportunities, reducing contention backoff delays and bandwidth wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cable modems use traditional sleep mode with pre-determined periodic cycles, then power consumption is reduced, but timing offset reacquisition becomes inefficient when waking up early due to lack of mechanism
Solution Approach 1:
The patent segments the sleep cycle into multiple wake-up opportunities, allowing cable modems to wake up at predetermined intervals rather than at a single fixed time. This segmentation enables the modem to reacquire timing offset efficiently when events occur during sleep mode, resolving the contradiction between power saving and timing reacquisition efficiency.
Solution Approach 2:
The patent establishes predetermined periodic wake-up cycles before the cable modem enters sleep mode. These pre-planned wake-up opportunities ensure that when early wake-up events occur, the modem can quickly reacquire timing offset without ad-hoc delays, thus maintaining both low power consumption and high productivity.
2Speed
If cable modems wake up early from sleep mode due to events, then responsiveness to events is improved, but timing offset adjustment becomes problematic due to lack of mechanism
Solution Approach 1:
The patent makes the wake-up schedule dynamic by allowing cable modems to wake up at predetermined periodic intervals rather than at a fixed time. This dynamic approach enables fast response to events while keeping the timing adjustment mechanism simple, as the modem only needs to follow the pre-established periodic wake-up schedule.
3Measurement precision
If cable modems use standard IUC3 regions for timing adjustment, then timing offset can be adjusted, but bandwidth is wasted due to larger region sizes and contention backoff delays
Solution Approach 1:
The patent changes the parameters of the IUC3 regions by reducing their size and increasing their frequency. Instead of using large, infrequent IUC3 regions, the system employs smaller, more frequent regions that allow cable modems to quickly adjust timing offset with minimal bandwidth consumption and no contention backoff delays.
Data Source
AI summary
A method in a cable modern (CM) to adjust its timing offset when waking up prior to the termination of its sleep cycle is provided. The method includes the step of receiving a service identifier (SID) for a multicast maintenance region, receiving a message from a cable modem termination system (CMTS) to enter a sleep cycle, waking up from the sleep cycle before the end of the sleep cycle in response to an event, and sending a message to the cable modem termination system (CMTS) to adjust the CM's timing offset during the multicast maintenance region.