Low-Latency Bluetooth Connectivity via Same-Interval Retransmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Bluetooth Low Energy (BLE) systems experience increased communication latency due to retry mechanisms, which affect user responsiveness in battery-powered devices, as they wait for multiple connection intervals to reestablish communication after packet loss.
Innovation Solution
Implementing a low-latency Bluetooth connectivity method where a central node and peripheral node use fixed-length packets, allowing retransmissions within the same connection interval, reducing retry latency from 20 milliseconds to less than 1 millisecond by synchronizing communication and omitting acknowledgement packets when initial packets are not received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional BLE retry mechanisms with increasing time delays are used, then power consumption is reduced, but communication latency increases
Solution Approach 1:
The patent implements preliminary action by pre-synchronizing the peripheral node to the central node's connection events before data transmission. The peripheral node adjusts its clock and transmission timing based on synchronization packets from the central node, ensuring it is ready to transmit and receive immediately when needed. This eliminates the need for multiple connection interval waits and enables same-interval retransmissions, reducing latency while maintaining low power consumption.
Solution Approach 2:
The patent applies dynamics by making the peripheral node's transmission timing adaptive rather than fixed. The peripheral node dynamically adjusts its transmission events to occur immediately after detecting the central node's synchronization packet, rather than waiting for predetermined connection intervals. This dynamic timing adjustment enables same-interval retransmissions and reduces communication latency while maintaining low-power operation.
2Productivity
If variable packet lengths are used in conventional BLE, then packet efficiency is improved, but retransmission latency increases to the next connection interval
Solution Approach 1:
The patent implements preliminary action by pre-establishing a fixed packet length for data transmissions. Both the central and peripheral nodes agree on the packet length during connection setup, eliminating the need for variable length negotiations. This fixed-length approach allows the peripheral node to immediately transmit data in the same connection interval without waiting for acknowledgment of variable-length packets, enabling same-interval retransmissions and reducing latency.
3Reliability
If acknowledgement packets are transmitted for every data packet, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies the extraction principle by removing the explicit acknowledgement packet mechanism from the communication protocol. Instead of transmitting separate ACK packets for every data packet, the system uses the presence or absence of the next synchronization packet from the central node as implicit acknowledgment. If the peripheral node receives the next sync packet, it knows its transmission was successful; if not, it performs same-interval retransmission. This eliminates the need for additional acknowledgement transmissions, reducing power consumption while maintaining reliability.
Data Source
AI summary
This document describes low-latency Bluetooth connectivity in a wireless network in which a central node and a peripheral node establish a connection. During a first connection interval, the peripheral node receives a packet from the central node to synchronize communication with the central node, and based on receiving the packet, the peripheral node transmits a first fixed-length packet. If the first fixed-length packet fails to reach the central node, the peripheral node does not receive an acknowledgement, ACK, from the central node during the first connection interval and retransmits the first fixed-length packet during the first connection interval.