DSL Modem Rate Adaptation for Fast Idle Exit
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Solution Overview
Problem
The existing DSL communication systems face challenges in minimizing the time required for parameter exchange during short initialization, which can lead to noticeable delays in reactivating DSL links, especially in VoIP applications, due to the time-consuming exchange of parameters between the CPE and CO modems.
Innovation Solution
Implementing logic circuitry in DSL modems to sense low or no communications traffic and perform seamless rate adaptation, reducing the data rate before entering a low power or idle state, thereby storing communications parameters that can be used to resume sessions without the need for parameter exchange during short initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the DSL link enters a low power or idle state to save energy, then power consumption is reduced, but the time required for parameter exchange during reactivation increases
Solution Approach 1:
The patent applies preliminary action by performing rate adaptation before the DSL link enters the low power or idle state. The system proactively reduces the data rate and stores the adapted parameters in memory, so that when reactivation is needed, the pre-adapted parameters can be immediately used without time-consuming parameter exchange, thus resolving the contradiction between power savings and reactivation time.
2Reliability
If seamless rate adaptation is performed to reduce data rate before entering idle state, then the operating margin is improved and parameter exchange frequency is reduced, but the device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the DSL modem to automatically perform rate adaptation and store parameters without external intervention or complex control mechanisms. The system monitors traffic conditions, autonomously decides when to adapt rates, executes the adaptation, and stores the parameters in memory, thereby improving reliability while minimizing the need for additional complex device components.
Data Source
AI summary
A digital subscriber line (DSL) system that provides fast exit from an idle state includes a central office (CO) modem for communicating with a customer premises equipment (CPE) modem. Prior to entry into a low-power or idle state for the DSL link between the CO modem and the CPE modem, seamless rate adaptation is performed in order to improve the operating margin from that used in full-on operation, for example by selecting a reduced data rate. Transmission parameters, including data rate, and bits and gains, and corresponding to the improved operating margin are stored at the modems. Upon executing short initialization to return from the idle state, the stored transmission parameters are more likely to be adequate to meet current channel conditions, so the exchange of transmission parameters during short initialization is more likely to be avoided.