Wireless Sync Code Keying for Bluetooth Power Savings

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Solution Overview

Problem

Current wireless communication devices face inefficiencies in power savings modes due to prolonged sync packet exchanges and unnecessary energy consumption during synchronization, particularly in Bluetooth systems, where devices often listen for sync packets across multiple frames even after receiving them.

Innovation Solution

Implementing a power savings mode where devices transmit and receive short synchronization packets within specific time slots, using codes derived from device identities to synchronize, and entering a reduced power state until the next cycle, with mechanisms to handle missed packets and clock drift, thereby minimizing energy expenditure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If devices listen for sync packets across multiple frames to ensure reliable synchronization, then synchronization reliability is improved, but energy consumption increases

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic synchronization where devices alternate between active listening periods and sleep periods. Instead of continuously listening for sync packets across all frames, devices listen only during designated synchronization intervals and then enter low-power sleep mode, reducing energy consumption while maintaining reliable synchronization through periodic checks.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent establishes synchronization parameters and time slots in advance before actual data transmission begins. Devices pre-negotiate and store synchronization timing information, allowing them to enter sleep mode confidently without needing to continuously monitor for sync packets, thus reducing energy consumption while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If devices transmit and receive sync packets frequently to maintain synchronization, then synchronization accuracy is improved, but energy consumption increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic synchronization where devices alternate between active listening periods and sleep periods. Instead of continuously listening for sync packets across all frames, devices listen only during designated synchronization intervals and then enter low-power sleep mode, reducing energy consumption while maintaining reliable synchronization through periodic checks.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses minimal sync packet transmissions at strategically chosen intervals rather than continuous transmissions. By sending sync packets only when necessary to correct drift and using short duration transmissions, the system achieves adequate synchronization accuracy with reduced energy consumption compared to frequent or continuous sync packet exchange.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If devices remain in active state to handle missed sync packets, then synchronization reliability is improved, but power savings are reduced

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidpower savings
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent incorporates error tolerance and recovery mechanisms that are pre-configured and stored in memory before devices enter sleep mode. When a sync packet is missed, devices can autonomously recover using pre-stored synchronization parameters and timing information without needing to remain actively powered on, thus maintaining reliability while achieving significant power savings.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent implements feedback mechanisms where devices monitor for sync packets during active periods and use the received timing information to adjust their sleep-wake cycles. This feedback allows devices to synchronize their sleep schedules with the actual transmission patterns of their counterparts, ensuring they wake up at the correct times to receive sync packets while maximizing power savings during idle periods.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2245887B1Code keying in a power savings mode
Publication Date: 2011.10.26 SONY ERICSSON MOBILE COMMUNICATIONS AB
  • EP2245887B1 patent drawingFigure 1
  • EP2245887B1 patent drawingFigure 2
  • EP2245887B1 patent drawingFigure 3

AI summary

A device may include logic to enter a power savings mode and wirelessly transmit a first synchronization packet to a remote device within a first transmission time slot in a first power savings cycle, the first synchronization packet including a code that is a member of a set consisting of a predetermined number of codes. In addition, the logic may be configured to sleep after transmitting the first synchronization packet to save energy, awake at a first receive time slot in the first power savings cycle, and receive a reply synchronization packet, the reply synchronization packet including a code is that is a member of the set from the remote device. The logic may be further configured to sleep until a start of a second power savings cycle that follows the first power savings cycle to save energy.