Efficient unicast super frame communications
In some examples, a vehicular battery management system (BMS) comprises a set of battery cells and a secondary network node coupled to the set of battery cells. The secondary network node is configured to wirelessly receive, in a first slot of a super frame, a unicast downlink packet from a primary network node, the unicast downlink packet addressed to the secondary network node. The secondary network node is also configured to wirelessly transmit, in a second slot of the super frame and responsive to the unicast downlink packet, an uplink packet to the primary network node.
1 . A vehicular battery management system (BMS), comprising:
a set of battery cells; and
a secondary network node coupled to the set of battery cells, the secondary network node configured to:
wirelessly receive, in a first slot of a super frame, a unicast downlink packet from a primary network node, the unicast downlink packet addressed to the secondary network node; and
wirelessly transmit, in a second slot of the super frame and responsive to the unicast downlink packet, an uplink packet to the primary network node.
2 . The BMS of claim 1 , wherein the first and second slots are consecutive slots.
3 . The BMS of claim 1 , wherein the secondary network node is configured to receive, in a third slot of the super frame, another unicast downlink packet from the primary network node, the other unicast downlink packet addressed to another secondary network node coupled to another set of battery cells.
4 . The BMS of claim 1 , wherein the secondary network node is configured to receive, in a third slot of the super frame, a broadcast downlink packet from the primary network node.
5 . The BMS of claim 4 , wherein the secondary network node is configured to refrain from transmitting another uplink packet to the primary network node in the super frame in response to the broadcast downlink packet.
6 . The BMS of claim 5 , wherein the secondary network node is configured to transmit the other uplink packet in a second super frame in response to a second broadcast downlink packet, the second super frame consecutive with the super frame.
7 . The BMS of claim 6 , wherein the second broadcast downlink packet is transmitted in the second super frame and has a payload identical to that of the broadcast downlink packet.
8 . The BMS of claim 6 , wherein the secondary network node is configured to transmit the other uplink packet in the second super frame responsive to the second broadcast downlink packet indicating that the other uplink packet was not received from the secondary network node in the super frame.
9 . The BMS of claim 5 , wherein the secondary network node is configured to:
determine a time slot in the super frame for the other uplink packet based on a default schedule; and
determine that the time slot has already occurred in the super frame,
wherein the secondary network node is configured configurable to, based on determining that the time slot has already occurred in the super frame, refrain from transmitting the other uplink packet to the primary network node in the super frame.
10 . A method, comprising: a primary network node transmitting, in a first super frame, a unicast downlink packet to a first secondary network node of a set of secondary network nodes and a broadcast downlink packet to the set of secondary network nodes; the primary network node receiving, in the first super frame and responsive to the unicast downlink packet, an uplink packet from the first secondary network node; and the primary network node receiving, in the first super frame and responsive to the broadcast downlink packet, additional uplink packets from fewer than all of the secondary network nodes in the set of secondary network nodes.
11 . The method of claim 10 , further comprising the primary network node transmitting, in a second super frame, a second broadcast downlink packet having a payload identical to a payload of the broadcast downlink packet.
12 . The method of claim 11 , wherein the second broadcast downlink packet includes an acknowledgement code indicating secondary network nodes in the set of secondary network nodes from which uplink packets were not received in the first super frame.
13 . The method of claim 12 , further comprising the primary network node receiving, in the second super frame, uplink packets from the secondary network nodes identified by the acknowledgement code.
14 . The method of claim 13 , wherein a timing of the uplink packets received from the secondary network nodes in the second super frame is based on the acknowledgement code.
15 . The method of claim 10 , wherein a timing of the uplink packets received from the secondary network nodes in the first super frame is based on a default schedule.
16 . A method, comprising:
a secondary network node transmitting, in a first super frame, a first uplink packet to a primary network node responsive to a unicast downlink packet received from the primary network node in the first super frame;
the secondary network node receiving, in the first super frame, a broadcast downlink packet from the primary network node and not transmitting a response to the broadcast downlink packet in the first super frame; and
the secondary network node transmitting, in a second super frame following the first super frame, a second uplink packet to the primary network node responsive to the broadcast downlink packet of the second super frame.
17 . The method of claim 16 , wherein the broadcast downlink packet of the second super frame has a payload identical to that of the broadcast downlink packet of the first super frame.
18 . The method of claim 16 , further comprising the secondary network node transmitting the second uplink packet in a slot of the second super frame determined based on an acknowledgement code in the broadcast downlink packet of the second super frame.
19 . The method of claim 18 , wherein the acknowledgement code indicates that the primary network node did not receive the response in the first super frame.
20 . The method of claim 16 , further comprising:
determining a time slot in the first super frame for the second uplink packet based on a default schedule; and
determining that the time slot has already occurred in the first super frame,
wherein not transmitting the response to the broadcast downlink packet in the first super frame is based on determining that the time slot has already occurred in the first super frame.