LE connected isochronous channels latency improvements
Disclosed are techniques to temporarily deactivate or activate the ACL link associated with an isochronous link between a central and a peripheral device of a BLE piconet. The central and peripheral devices may agree to enter into an ACL parked mode after an isochronous link is established between the devices. In the parked mode, the ACL link is in a dormant state without any ACL events. If the central or the peripheral device wants to activate the ACL link to transmit one or more control or data packets, the device may use a CIS subevent on the isochronous link to transmit an LL control PDU. The LL control PDU may contain ACL timing information that specifies the timing of the future ACL event. The device may specify the ACL timing information to avoid or reduce chances of collisions of the future ACL event with CIS packets on the isochronous link.
1 . A method for communication between a first device and a second device of a communication network, comprising:
configuring, by the first device, an inactive state for a first link between the first device and the second device, the first link configured to transport asynchronous events and share airtime with a second link that is configured to transport isochronous events between the first device and the second device;
transmitting, by the first device to the second device over the second link, a control packet, the control packet comprising a link layer control protocol data unit (PDU) that indicates an intention to activate the first link;
receiving, by the first device from the second device over the second link, an acknowledgement of the control packet;
communicating, by the first device with the second device, over an asynchronous event of the first link; and
configuring, by the first device, the first link back to the inactive state.
2 . The method of claim 1 , wherein during the inactive state of the first link, the first device is refrained from communicating with the second device over the first link.
3 . The method of claim 1 , wherein configuring an inactive state for the first link comprises:
establishing, by the first device with the second device, the second link based on the first link being in an active state; and
agreeing, between the first device and the second device, to refrain from transmitting over the first link after establishing the second link.
4 . The method of claim 1 , wherein transmitting the control packet over the second link comprises:
transmitting, by the first device to the second device, the control packet during an isochronous event of the second link, wherein the control packet includes timing information to indicate timing of the asynchronous event of the first link intended for communicating between the first device and the second device.
5 . The method of claim 4 , wherein the timing information comprises an offset of a start of the asynchronous event of the first link from an end of the isochronous event of the second link.
6 . The method of claim 4 , wherein communicating over the asynchronous event of the first link comprises:
scheduling, by the first device, the timing of the asynchronous event of the first link based on the timing information; and
transmitting, by the first device to the second device, a packet over the first link during the asynchronous event.
7 . The method of claim 4 , further comprising:
determining, by the first device, the timing of the asynchronous event to avoid a collision between the asynchronous event of the first link and any isochronous events of the second link.
8 . The method of claim 4 , wherein communicating over the asynchronous event of the first link comprises:
scheduling, by the first device, periodic asynchronous events of the first link, wherein the timing of a first asynchronous event of the periodic asynchronous events is based on the timing information; and
exchanging, between the first device to the second device, a plurality of packets over the first link during the periodic asynchronous events.
9 . The method of claim 1 , further comprising:
retransmitting, by the first device to the second device, the control packet over the second link when the first device fails to receive the acknowledgement of the control packet from the second device.
10 . The method of claim 1 , wherein configuring the first link back to the inactive state comprises:
transmitting, by the first device to the second device, a second control packet over the second link, the second control packet indicating an intention to deactivate the first link;
receiving, by the first device from the second device, an acknowledgement of the second control packet; and
agreeing, between the first device and the second device, to refrain from transmitting over the first link.
11 . The method of claim 1 , wherein the communication network comprises a Bluetooth Low Energy (BLE) network, wherein the first device comprises a central device of the BLE wireless network, wherein the second devices comprises a peripheral device of the BLE wireless network, wherein the first link comprises a BLE asynchronous connection-oriented logical transport (ACL) link, and wherein the second link comprises an isochronous link for a BLE connected isochronous stream (CIS).
12 . The method of claim 1 , wherein the communication network comprises a Bluetooth Low Energy (BLE) network, wherein the first device comprises a peer device of the BLE wireless network, wherein the second devices comprises a central device of the BLE wireless network, wherein the first link comprises a BLE asynchronous connection-oriented logical transport (ACL) link, and wherein the second link comprises an isochronous link for a BLE connected isochronous stream (CIS).
13 . An apparatus comprising:
a transceiver configured to transmit or receive packets over a first link and a second link with a peer device, the first link configured to transport asynchronous events, the second link configured to transport isochronous events, the first link and the second link sharing airtime;
a processing system configured to:
configure the transceiver to stop communication over the first link;
transmit to the peer device, via the transceiver, a control packet over the second link, the control packet comprising a link layer control protocol data unit (PDU) that indicates an intention to activate the first link;
receive from the peer, device via the transceiver, an acknowledgement of the control packet over the second link;
communicate with the peer device, via the transceiver, over an asynchronous event of the first link; and
configure the transceiver to again stop communicating over the first link.
14 . The apparatus of claim 13 , wherein to transmit to the peer device the control packet over the second link, the processing system is configured to:
transmit to the peer device, via the transceiver, the control packet during an isochronous event of the second link, wherein the control packet includes timing information to indicate timing of the asynchronous event of the first link.
15 . The apparatus of claim 14 , wherein the timing information comprises an offset of a start of the asynchronous event of the first link from an end of the isochronous event of the second link.
16 . The apparatus of claim 14 , wherein to communicate with the peer device over an asynchronous event of the first link, the processing system is configured to:
schedule the timing of the asynchronous event of the first link based on the timing information; and
transmit to the peer device, via the transceiver, a packet over the first link during the asynchronous event.
17 . The apparatus of claim 14 , wherein to communicate with the peer device over an asynchronous event of the first link, the processing system is configured to:
determine the timing of the asynchronous event to avoid a collision between the asynchronous event of the first link and any isochronous events of the second link.
18 . The apparatus of claim 14 , wherein to communicate with the peer device over an asynchronous event of the first link, the processing system is configured to:
schedule periodic asynchronous events of the first link, wherein the timing of a first asynchronous event of the periodic asynchronous events is based on the timing information; and
exchange with the peer device, via the transceiver, a plurality of packets over the first link during the periodic asynchronous events.
19 . The apparatus of claim 13 , wherein to configure the transceiver to again stop communicating over the first link, the processing system is configured to:
transmit to the peer device, via the transceiver, a second control packet over the second link, the second control packet indicating an intention to deactivate the first link;
receive from the peer, device via the transceiver, an acknowledgement of the second control packet over the second link; and
agree with the peer device to stop communicating over the first link.
20 . The apparatus of claim 13 , wherein the apparatus comprises a peer device of a Bluetooth Low Energy (BLE) wireless network, wherein the second devices comprises a central device of the BLE wireless network, wherein the first link comprises a BLE asynchronous connection-oriented logical transport (ACL) link, and wherein the second link comprises an isochronous link for a BLE connected isochronous stream (CIS).