Timing alignment in integrated access and backhaul
Apparatuses, methods, and systems are disclosed for timing alignment in integrated access and backhaul. A method includes receiving, at an integrated access and backhaul (“IAB”) node of a wireless communication network, a first configuration for receiving a downlink reference signal and a second configuration for receiving an uplink reference signal. The method includes determining timing alignment information associated with the downlink reference signal and the uplink reference signal. The method includes determining, based on the timing alignment information, a timing misalignment value. The method includes computing a second reception time based on a first reception time and the timing misalignment value, the first reception time determined based on the downlink reference signal. The method includes applying the second reception time to the TAB node for receiving the uplink reference signal.
1 . A method, comprising:
receiving, at an integrated access and backhaul (“IAB”) node, a first reference signal according a first configuration;
determining a first reception time based on the first reference signal;
receiving a timing misalignment value;
computing a second reception time based on the first reception time and the timing misalignment value;
applying the second reception time to the IAB node for receiving a second reference signal according to a second configuration; and
performing measurement on the second reference signal received at the second reception time.
2 . The method of claim 1 , further comprising:
transmitting a report comprising information from the performed measurement, the measurement comprising a reference signal received power (“RSRP”) measurement.
3 . The method of claim 1 , wherein computing the second reception time comprises:
obtaining a start time of a first slot, wherein the first slot comprises the first reference signal; and
computing a start time of a second slot as the timing misalignment value minus the start time of the first slot plus an integer multiple of a slot duration, the second slot comprising the second reference signal, the integer multiple obtained based on the first configuration and the second configuration.
4 . The method of claim 1 , wherein the second reception time is further based on a second timing misalignment value received from a serving cell.
5 . The method of claim 1 , wherein the second reception time is further based on a received third configuration of a timing alignment mode.
6 . The method of claim 5 , wherein computing the second reception time comprises, in response to determining that the timing alignment mode is a transmission timing alignment mode, computing the second reception time as the first reception time plus an integer multiple of a symbol time.
7 . The method of claim 1 , wherein:
the first configuration is a synchronization signal block (“SSB”) measurement timing configuration (“SMTC”);
the first reference signal is a synchronization signal and physical broadcast channel (“SS/PBCH”) block;
the second configuration is a sounding reference signal reference signal receive power (“SRS-RSRP”) configuration; and
the second reference signal is a sounding reference signal (“SRS”).
8 . An apparatus, comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the apparatus to:
receive, at an integrated access and backhaul (“IAB”) node, a first reference signal according a first configuration;
determine a first reception time based on the first reference signal;
receive a timing misalignment value;
compute a second reception time based on the first reception time and the timing misalignment value;
apply the second reception time to the IAB node for receiving a second reference signal according to a second configuration; and
perform measurement on the second reference signal received at the second reception time.
9 . The apparatus of claim 8 , wherein the at least one processor is configured to cause the apparatus to:
transmit a report comprising information from the performed measurement, the measurement comprising a reference signal received power (“RSRP”) measurement.
10 . The apparatus of claim 8 , wherein the at least one processor is configured to cause the apparatus to compute the second reception time by:
obtaining a start time of a first slot, wherein the first slot comprises the first reference signal; and
computing a start time of a second slot as the timing misalignment value minus the start time of the first slot plus an integer multiple of a slot duration, the second slot comprising the second reference signal, the integer multiple obtained based on the first configuration and the second configuration.
11 . The apparatus of claim 8 , wherein the second reception time is further based on a second timing misalignment value received from a serving cell.
12 . The apparatus of claim 8 , wherein the second reception time is further based on a received third configuration of a timing alignment mode.
13 . The apparatus of claim 12 , wherein the at least one processor is configured to cause the apparatus to compute the second reception time by, in response to determining that the timing alignment mode is a transmission timing alignment mode, computing the second reception time as the first reception time plus an integer multiple of a symbol time.
14 . The apparatus of claim 8 , wherein:
the first configuration is a synchronization signal block (“SSB”) measurement timing configuration (“SMTC”);
the first reference signal is a synchronization signal and physical broadcast channel (“SS/PBCH”) block;
the second configuration is a sounding reference signal reference signal receive power (“SRS-RSRP”) configuration; and
the second reference signal is a sounding reference signal (“SRS”).
15 . An apparatus, comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the apparatus to:
receive a first configuration for transmitting a first reference signal and a second configuration for transmitting second reference signal;
determine timing alignment information based on a first transmission time of the first reference signal and a second transmission time of the second reference signal; and
compute, based on the timing alignment information, a timing misalignment value associated with the first transmission time and the second transmission time of;
transmit the first reference signal at the first transmission time;
transmit the timing misalignment value; and
transmit the second reference signal at the second transmission time.
16 . The apparatus of claim 15 , wherein the timing misalignment value equals a second start time of a second slot comprising the second reference signal minus a first start time of a first slot comprising the first reference signal minus an integer multiple of a slot duration.
17 . The apparatus of claim 16 , wherein the integer multiple is obtained based on the first configuration and the second configuration.
18 . The apparatus of claim 15 , wherein the at least one processor is configured to cause the apparatus to, in response to determining that a timing alignment mode is a transmission timing alignment mode, compute a second reception time as a first reception time plus an integer multiple of a symbol time.
19 . The apparatus of claim 15 , wherein the at least one processor is configured to cause the apparatus to transmit the timing misalignment value in a system information block (“SIB”) associated with the first reference signal or to a serving cell.
20 . The apparatus of claim 15 , wherein the at least one processor is configured to cause the apparatus to obtain the timing alignment information by receiving a third configuration for a timing alignment scheme or receiving a timing alignment control message from a serving cell.