Packet Buffer Clock Control for Power Reduction

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Solution Overview

Problem

Packet communication devices face high power consumption due to constant clock signal supply even when no packet processing is required, leading to increased standby power consumption and reduced throughput during low traffic periods.

Innovation Solution

A packet processing apparatus that includes a clock control unit that measures the time when no packet data is accumulated in the buffer and adjusts the clock signal supply accordingly, either suspending it or reducing its frequency, to minimize power consumption without affecting data processing throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If clock signal is constantly supplied to packet processing unit, then data processing throughput is maintained, but power consumption increases significantly during low traffic periods

Engineering Contradiction:
Improvedata processing throughputVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the clock signal supply adjustable rather than fixed. The clock control unit dynamically changes the clock supply state based on buffer occupancy detection - providing full clock signals when packets are present and suspending or reducing clock supply when the buffer is empty, thereby adapting the system state to actual workload conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback through the buffer occupancy detection unit that continuously monitors packet buffer status and provides information to the clock control unit. This feedback loop enables the system to automatically adjust clock supply based on real-time packet processing needs, resolving the contradiction between maintaining throughput and reducing power consumption

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If clock signal supply is suspended when no packet data is present, then power consumption is reduced, but data processing throughput may be affected

Engineering Contradiction:
Improvepower consumptionVSAvoiddata processing throughput
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent applies preliminary action by having the buffer occupancy detection unit continuously monitor packet buffer status before clock supply suspension occurs. This advance detection allows the system to prepare for potential packet arrivals and ensure that clock supply can be quickly restored when needed, preventing throughput degradation while maintaining power savings

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If asynchronous circuit configuration is adopted, then power consumption is reduced in both normal operation and standby state, but development tools and verification capabilities are insufficient

Engineering Contradiction:
Improvepower consumptionVSAvoiddevelopment and verification capability
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the operational parameters of the clock signal based on buffer occupancy conditions. Instead of adopting a completely asynchronous configuration, the system changes clock supply parameters (frequency, presence/absence) dynamically based on actual packet processing needs, achieving power reduction while maintaining compatibility with existing synchronous design tools and methodologies

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2113823B1Packet processing apparatus
Publication Date: 2021.04.21 RAKUTEN GROUP INC
  • EP2113823B1 patent drawingFigure 1
  • EP2113823B1 patent drawingFigure 2
  • EP2113823B1 patent drawingFigure 3

AI summary

A packet processing apparatus includes a packet buffer unit that temporarily holds packet data, a packet processing unit that processes packet data output from the packet buffer unit, a clock supply unit that supplies a clock signal to the packet processing unit, and a control unit that detects a buffer vacant time indicating a time during which no packet data exists in the packet buffer unit based on an accumulation amount of the packet data in the packet buffer unit, and controls an operational state of the clock supply unit in accordance with the buffer vacant time.