Bluetooth Scheduling with Overrule Mechanism for Latency and Airtime

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Solution Overview

Problem

Existing scheduling algorithms for Bluetooth-like communications systems face challenges in efficiently multiplexing low latency and best effort data streams, leading to wasted airtime and increased processing load, as they struggle to prioritize retransmissions and ensure guaranteed latency while maximizing best effort traffic opportunities.

Innovation Solution

A prescheduling strategy that employs an overrule mechanism and allocation windows, where low latency data streams are guaranteed retransmission opportunities without interruption, and unused retransmission frames are allocated to best effort data streams, optimizing airtime usage without increasing the scheduler's processing load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If retransmission opportunities are guaranteed for low latency data streams, then latency reliability is improved, but airtime utilization deteriorates due to unused retransmission frames

Engineering Contradiction:
Improvelatency reliabilityVSAvoidairtime utilization
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent recovers unused retransmission frames by allowing best effort data streams to utilize them. When low latency retransmissions are not needed, the previously wasted airtime is now allocated to best effort traffic, effectively recovering lost resource utilization while maintaining the guaranteed retransmission opportunities when needed.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The scheduling mechanism dynamically adjusts frame allocation based on actual transmission needs. The system transitions from static guaranteed retransmission slots to dynamic allocation where best effort streams can occupy unused retransmission frames, optimizing airtime utilization according to real-time conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If scheduling algorithms prioritize low latency retransmissions, then latency guarantee is improved, but processing load increases

Engineering Contradiction:
Improvelatency guaranteeVSAvoidprocessing load
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses prescheduling to pre-determine retransmission opportunities before they are needed. By establishing the scheduling framework in advance, the system eliminates complex real-time decisions during actual transmission, reducing processing load while maintaining latency guarantees.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If airtime is reserved for retransmissions, then latency reliability is improved, but throughput of best effort traffic deteriorates

Engineering Contradiction:
Improvelatency reliabilityVSAvoidthroughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent recovers airtime previously discarded during retransmission opportunities by allocating it to best effort traffic. This increases overall system throughput by ensuring that airtime not used for guaranteed retransmissions is not wasted but instead utilized for additional data transmission.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2898725B1Scheduling best effort traffic with cuaranteed latency traffic in a communications system having a bluetooth-like packet communication protocol
Publication Date: 2016.10.05 OCT CIRCUIT TECH INT LTD
  • EP2898725B1 patent drawingFigure 1a~1c
  • EP2898725B1 patent drawingFigure 2a~2c
  • EP2898725B1 patent drawingFigure 3a~3c

AI summary

Time frames (TFs) are allocated for performance of transactions of a low latency data stream (LLDS) and a best effort data stream (BEDS) in Bluetooth®-like equipment, wherein payload carrying packets of the different data streams are equal in size, each occupying multiple TFs. An overrule mechanism enables uncompleted transactions of one data stream to continue as needed into TFs allocated to another data stream. Every TF within an allocation window (AW) is individually allocated to the LLDS or the BEDS, and plural TFs immediately following the AW form a guard space between adjacent AWs, the guard space being allocated to neither the LLDDS or the BEDS. Configuration of the AW and of the guard space guarantees the LLDS a first opportunity to transmit a payload carrying packet and continued opportunities to retransmit the packet until successful, after which the BEDS is given an opportunity for transmission and possible retransmissions.