End-to-end latency measurement
End-to-end latency measurements for synchronization are described. A first wireless device may determine an uplink latency associated with sending communications to a second wireless device. The first wireless device may determine a downlink latency associated with receiving communications from the second wireless device. Based on the uplink latency being different from the downlink latency, the first wireless device, the second wireless, and/or a base station may perform an alignment (e.g., time-based alignment, channel-based alignment) to modify and/or adjust one or more parameters to make the uplink latency equivalent to the downlink latency.
1 . A method comprising:
receiving, by a base station, a request to measure an end-to-end latency between a first wireless device and a second wireless device;
measuring a first end-to-end latency between the first wireless device and the base station, wherein the first end-to-end latency comprises a first uplink latency and a first downlink latency;
measuring a second end-to-end latency between the second wireless device and the base station, wherein the second end-to-end latency comprises a second uplink latency and a second downlink latency; and
sending, to the first wireless device, a response indicating the end-to-end latency between the first wireless device and the second wireless device, wherein the end-to-end latency is based on the first end-to-end latency and the second end-to-end latency.
2 . The method of claim 1 , further comprising sending, the second wireless device, an indication of the end-to-end latency between the first wireless device and the second wireless device.
3 . The method of claim 1 , wherein the end-to-end latency comprises at least one of:
a duration to deliver a communication from a first network element to a second network element;
a duration to deliver a communication from the first wireless device to the second wireless device; or
a duration to deliver a communication from the first wireless device to the base station.
4 . The method of claim 1 , wherein the request to measure the end-to-end-latency comprises at least one of:
a radio resource control (RRC) message;
a registration request message; or
a protocol data unit (PDU) session request message.
5 . The method of claim 1 , wherein the request to measure the end-to-end-latency comprises at least one of:
an identifier of the first wireless device; or
an identifier of the second wireless device.
6 . The method of claim 1 , wherein the measuring the end-to-end latency between the first wireless device and the second wireless device is based on at least one of:
a data radio bearer for the first wireless device;
a signaling radio bearer for the first wireless device;
a network slice associated with a protocol data unit (PDU) session for the first wireless device;
a Quality-of-Service (QoS) associated with a PDU session for the first wireless device; or
a service data flow associated with a PDU session for the first wireless device.
7 . The method of claim 1 , wherein the response message comprises at least one of:
one or more RRC messages
a registration response message; or
a PDU session response message.
8 . The method of claim 1 , wherein the end-to-end latency is based on a combination of the first end-to-end latency and the second end-to-end latency.
9 . The method of claim 1 , further comprising:
modifying, based on the end-to-end latency between the first wireless device and the second wireless device, one or more first parameters to establish a symmetric uplink communication channel between the first wireless device and the second wireless device; and
modifying, based on the end-to-end latency between the first wireless device and the second wireless device, one or more second parameters to establish a symmetric downlink communication channel between the first wireless device and the second wireless device.
10 . A method comprising:
sending, by a first wireless device to a network element, a request to measure an end-to-end latency between the first wireless device and a second wireless device;
receiving the measured end-to-end latency, wherein the measured end-to-end latency comprises an uplink latency measurement and a downlink latency measurement;
sending, by the first wireless device to the second wireless device, a message indicating an alignment between the first wireless device and the second wireless device; and
performing, based on the measured end-to-end latency, an alignment between the first wireless device and the second wireless device.
11 . The method of claim 10 , wherein the request comprises at least one of:
a radio resource control (RRC) connection; or
a protocol data unit (PDU) session.
12 . The method of claim 10 , wherein the network element comprises at least one of:
a base station;
an access and mobility management function (AMF);
a network function (NEF);
a session management function (SMF); or
a user plane function (UPF).
13 . The method of claim 10 , wherein the alignment comprises at least one of:
channel-based alignment; or
time-based alignment.
14 . The method of claim 10 , wherein the alignment comprises a channel-based alignment for line current differential protection.
15 . A method comprising:
receiving, by a base station, a request to measure an end-to-end latency between a first wireless device and a second wireless device;
measuring a first end-to-end latency between the base station and the first wireless device, wherein the first end-to-end latency comprises a first uplink latency and a first downlink latency;
measuring a second end-to-end latency between the base station and the second wireless device, wherein the second end-to-end latency comprises a second uplink latency and a second downlink latency; and
sending, based on the first end-to-end latency and based on the second end-to-end latency, a response indicating the end-to-end latency between the first wireless device and the second wireless device.
16 . The method of claim 15 , wherein the measuring the first end-to-end latency between the base station and the first wireless device comprises determining a difference between a first timestamp and a second timestamp.
17 . The method of claim 1 , wherein:
the first uplink latency comprises transmissions from the first wireless device to the base station; and
the first downlink latency comprises transmissions from the base station to the second wireless device.
18 . The method of claim 10 , wherein:
the uplink latency measurement comprises transmissions from the wireless device to the network element; and
the downlink latency measurement comprises transmissions from the network element to the second wireless device.
19 . The method of claim 15 , wherein:
the first uplink latency comprises transmissions from the first wireless device to the base station; and
the first downlink latency comprises transmissions from the base station to the second wireless device.
20 . The method of claim 19 , wherein:
the second uplink latency comprises transmissions from the second wireless device to the base station; and
the second downlink latency comprises transmissions from the base station to the first wireless device.