Bluetooth Controller Packet Retransmission Mechanism
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Solution Overview
Problem
Conventional Bluetooth communication systems experience a high probability of packet retransmission, especially when devices are far apart or communication is obstructed, leading to inefficiencies in audio packet transmission.
Innovation Solution
A Bluetooth device controller employs flags and counters to track successful packet receptions and acknowledgments between primary and secondary devices, sending negative acknowledgments when a threshold of unreceived packets is reached, thereby reducing unnecessary retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Bluetooth communication is used, then devices can communicate wirelessly, but the number of packet retransmissions increases significantly
Solution Approach 1:
The patent implements a feedback mechanism where the primary device monitors packet reception status and sends negative acknowledgments (NACK) to the audio gateway when packets are lost. The gateway then retransmits only the specific lost packets rather than all packets, improving reliability while maintaining efficiency through selective retransmission based on actual reception status feedback.
Solution Approach 2:
The patent employs preliminary error detection at the primary device before forwarding audio to the secondary device. By detecting packet loss in advance and triggering selective retransmission requests, the system prevents propagation of lost packets to the secondary device, thereby improving overall communication reliability without requiring full retransmission sequences.
2Adaptability or versatility
If devices are farther away or communication is obstructed, then wireless communication flexibility is maintained, but packet reception success rate decreases
Solution Approach 1:
The patent implements dynamic adaptive retransmission where the system adjusts its behavior based on real-time reception conditions. When packet loss is detected (indicating poor reception conditions due to distance or obstruction), the system activates selective retransmission mechanisms. This dynamic response allows the system to maintain reliability in challenging wireless environments while preserving the flexibility of wireless communication.
3Reliability
If audio packets are retransmitted frequently, then packet delivery reliability improves, but system performance and communication efficiency deteriorate
Solution Approach 1:
The patent extracts and identifies only the specific lost packets that require retransmission, rather than retransmitting all audio packets. The primary device compares received packet sequences, identifies gaps, and sends NACK messages containing only the indices of lost packets. The audio gateway then retransmits only those specific packets, significantly reducing unnecessary retransmissions and maintaining system performance while ensuring reliable delivery.
Solution Approach 2:
The patent changes the retransmission parameter from 'retransmit all packets' to 'retransmit only lost packets identified by packet index'. This parameter change in the retransmission strategy reduces the volume of retransmitted data from potentially all packets to only the specific lost ones, thereby improving system performance while maintaining packet delivery reliability.
Data Source
AI summary
A method applied into a controller of a Bluetooth device includes: providing a first flag and a second flag which are configured as a default value respectively; changing the first flag from the default value when the controller successfully receives the particular packet transmitted from the audio gateway; changing the second flag from the default value when the controller successfully receives an acknowledgement from a secondary device wherein a reception of the acknowledgement indicates that the secondary device successfully receives the particular packet; and transmitting an acknowledgement of a particular packet to an audio gateway when detecting that either the first flag or the second flag changes and becomes different from the default value.