Synchronization of bluetooth low energy isochronous transmissions
View Patent ↗Mechanisms and methods are provided for improving wireless audio transmission and synchronization for multi-channel Bluetooth® Low Energy (BLE) systems. In various embodiments, mechanisms and methods may include generating transmissions having a plurality of Protocol Data Units (PDUs) to BLE-compliant slave devices. The plurality of PDUs may be stored in a buffer. When an error is determined to have occurred in transmitting one of the PDUs, a re-transmission to the slave device may be generated, which may include the PDU in error and any subsequent PDUs of the plurality of PDUs.
1. A method of synchronizing transmissions for multiple audio channels, the method comprising:
generating a first transmission to a first Bluetooth Low Energy compliant (BLE-compliant) slave device in a first Connected Isochronous Stream (CIS) event of a first Connected Isochronous Group (CIG), the first transmission including a first set of Protocol Data Units (PDUs);
generating a second transmission to a second BLE-compliant slave device in a second CIS event of the first CIG, the second transmission including a second set of PDUs;
determining, based upon detecting a lost PDU of the first set of PDUs, whether to generate a first re-transmission to the first BLE-compliant slave device in a first CIS event of a second CIG, the first re-transmission including the lost PDU of the first set of PDUs and one or more subsequent PDUs of the first set of PDUs; and
determining, based upon detecting a lost PDU of the second set of PDUs, whether to generate a second re-transmission to the second BLE-compliant slave device in a second CIS event of the second CIG, the second re-transmission including the lost PDU of the second set of PDUs and one or more subsequent PDUs of the second set of PDUs.
2. The method of claim 1 , further comprising:
storing the first set of PDUs in a first buffer; and
storing the second set of PDUs in a second buffer.
3. The method of claim 2 ,
wherein at least one of a size in PDUs of the first buffer and a size in PDUs of the second buffer is dynamically adjustable.
4. The method of claim 3 ,
wherein the dynamic adjustment is based upon a frequency of flushing the buffer.
5. The method of claim 1 ,
wherein each PDU of the first set of PDUs carries audio data for a first audio channel; and
wherein each PDU of the second set of PDUs carries audio data for a second audio channel.
6. The method of claim 5 ,
wherein the first audio channel and the second audio channel are channels of a set of True Wireless Stereo (TWS) audio channels.
7. The method of claim 1 ,
wherein the detection of a lost PDU is based on one of: receiving a Negative Acknowledgement (NAK) transmission from the BLE-compliant slave device; or an absence of a received Acknowledgement (ACK) transmission from the BLE-compliant slave device.
8. A wireless personal area network master device, comprising:
one or more antennas;
one or more processors; and
a memory storing a plurality of instructions that, when executed, cause the one or more processors to:
generate a first transmission to a first Bluetooth Low Energy compliant (BLE-compliant) slave device, the first transmission including a first plurality of Protocol Data Units (PDUs);
generate a second transmission to a second BLE-compliant slave device, the second transmission including a second plurality of PDUs;
determine, based upon detecting a lost PDU of the first plurality of PDUs, whether to generate a first re-transmission to the first BLE-compliant slave device, the first re-transmission including the lost PDU of the first plurality of PDUs and any subsequent PDUs of the first plurality of PDUs; and
determine, based upon detecting a lost PDU of the second plurality of PDUs, whether to generate a second re-transmission to the second BLE-compliant slave device, the second re-transmission including the lost PDU of the second plurality of PDUs and any subsequent PDUs of the second plurality of PDUs.
9. The BLE-compliant master device of claim 8 ,
wherein the first plurality of PDUs carries audio data for a first audio channel of a set of True Wireless Stereo (TWS) audio channels; and
wherein the second plurality of PDUs carries audio data for a second audio channel of the set of TWS audio channels.
10. The BLE-compliant master device of claim 8 , the processors further to:
storing the first plurality of PDUs in a first buffer; and
storing the second plurality of PDUs in a second buffer.
11. The BLE-compliant master device of claim 10 ,
wherein at least one of a size in PDUs of the first buffer and a size in PDUs of the second buffer is dynamically adjustable.
12. The BLE-compliant master device of claim 8 ,
wherein the detection of a lost PDU is based on one of: a received Negative Acknowledgement (NAK) transmission from a BLE-compliant slave device; or an absence of a received Acknowledgement (ACK) transmission from the BLE-compliant slave device.