In-flight Entertainment Bluetooth Broadcast Rate Control
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Solution Overview
Problem
The proliferation of Bluetooth devices in aircraft cabins leads to communication interference, degrading or intermittently preventing the operation of in-flight entertainment systems due to unsynchronized use of shared radio resources.
Innovation Solution
Implementing a system where seat video display units (SVDUs) receive a master time reference from satellite or ground networks and adjust their Bluetooth broadcast rates based on user terminal requests, transmitting time messages at scheduled intervals to minimize interference and ensure accurate time reference distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Bluetooth devices transmit time messages at high broadcast rates to ensure accurate time reference distribution, then time accuracy is improved, but radio frequency interference increases
Solution Approach 1:
The system implements periodic time message broadcasts at scheduled intervals rather than continuous transmission. The Bluetooth controller determines a scheduled time broadcast rate and transmits time messages at specific time instances based on this rate, reducing overall radio frequency interference while maintaining adequate time accuracy for user terminal applications.
Solution Approach 2:
The system dynamically adjusts the time broadcast rate parameter based on user terminal requests and current interference conditions. The Bluetooth controller receives rate request messages from user terminals indicating desired time broadcast rates, then determines an optimal scheduled rate that balances time accuracy requirements with radio frequency interference mitigation.
2Loss of information
If multiple Bluetooth devices transmit simultaneously without synchronization to provide time references, then time reference availability is improved, but communication interference increases
Solution Approach 1:
The system merges the time message transmission function into a coordinated network operation where multiple SVDU Bluetooth controllers synchronize their broadcasts. Rather than independent simultaneous transmissions, the controllers operate as a coordinated system that provides comprehensive time reference coverage while minimizing interference through synchronized scheduling.
Solution Approach 2:
The system implements feedback mechanisms where Bluetooth controllers receive rate request messages from user terminals indicating their time accuracy needs. This feedback information is used to adjust the scheduled time broadcast rate, ensuring adequate time reference availability while optimizing transmission frequency to reduce communication interference.
Data Source
AI summary
An inflight entertainment system includes video display units that communicate with user terminals through Bluetooth signaling and include a network interface communicating with a content server and a satellite network interface and/or a ground network interface. A time reference message is received which contains a master time reference from the satellite network interface and/or the ground network interface. A local time generator is updated based on the master time reference. Rate request messages are received from the user terminals containing indications of time broadcast rates requested by the user terminals. A scheduled time broadcast rate is determined based on the indications of the time broadcast rates requested by the user terminals. The video display unit transmits, through a Bluetooth transceiver at time instances which are determined based on the scheduled time broadcast rate, broadcast time messages that each contain an indication of a present local time of the video display unit.