Timing and frequency adjustments in non-terrestrial networks
Apparatuses, methods, and systems are disclosed for timing and frequency adjustments in non-terrestrial networks. One apparatus includes a processor that determines a first frequency from one of a first reference signal received from a mobile wireless communication network and a configuration message received from the mobile wireless communication network. The processor determines a second frequency from a second reference signal received from the mobile wireless communication network. The processor computes a second timing advance value based on a first timing advance value, the first determined frequency, and the second determined frequency, the first timing advance value received as part of a control message. The apparatus includes a transceiver that transmits, to the mobile wireless communication network, an uplink signal using the second timing advance value.
1 . A user equipment (UE), comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the UE to:
determine a first frequency from one of a first reference signal received from a mobile wireless communication network and a configuration message received from the mobile wireless communication network;
determine a second frequency from a second reference signal received from the mobile wireless communication network;
compute a second timing advance value based on a first timing advance value, the first determined frequency, and the second determined frequency, the first timing advance value received as part of a control message, wherein computing the second timing advance value comprises computing a difference between a first time and a second time, the first time associated with a time when the first timing advance value is received, and the second time associated with a time when an uplink signal is transmitted; and
transmit, to the mobile wireless communication network, an uplink signal using the second timing advance value.
2 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to receive an indication that the second reference signal is not altered for a Doppler pre-compensation, the Doppler pre-compensation comprising a frequency shift in a transmitter.
3 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to compute the second timing advance value by computing a ratio of the second determined frequency to the first determined frequency.
4 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to compute the second timing advance value as a function of the first timing advance value plus a delta timing advance value, wherein:
the delta timing advance value is equal to two times a coefficient times a time difference value;
the coefficient comprises a ratio of the second frequency to the first frequency minus one;
the time difference value comprises a difference between a first time and a second time;
the first time is associated with a time when the first timing advance value is received; and
the second time is associated with a time when the uplink signal is transmitted.
5 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to cause the UE to compute the second time advance value according to a pre-defined time function that considers the first timing advance value, the first determined frequency, and the second determined frequency.
6 . The UE of claim 1 , wherein the control message further comprises an expiration timer value such that transmitting the uplink signal using the second timing advance value is performed in response to determining that a first time associated with a time when the control message is received plus the expiration timer value is larger than a second time associated with a time when the uplink signal is transmitted.
7 . The UE of claim 6 , wherein the at least one processor is configured to cause the UE to transmit the uplink signal using the second timing advance value in response to receiving at least one of:
an indication of a quasi-collocation relationship between the first reference signal and the second reference signal;
an indication of a quasi-collocation relationship between the first reference signal and the first timing advance value; and
an indication of a quasi-collocation relationship between the second reference signal and the first timing advance value.
8 . The UE of claim 1 , wherein the first reference signal comprises a first synchronization signal and the second reference signal comprises a second synchronization signal.
9 . The UE of claim 1 , wherein the first frequency comprises at least one of a carrier frequency, a carrier frequency without a Doppler pre-compensation, a carrier frequency with a Doppler pre-compensation, and a Doppler pre-compensation frequency.
10 . The UE of claim 1 , wherein at least a portion of the mobile wireless communication network comprises a non-terrestrial network that provides a wireless connection between a user equipment (“UE”) and a gateway of a terrestrial network.
11 . A method performed by a user equipment (UE), the method comprising:
determining a first frequency from one of a first reference signal received from a mobile wireless communication network and a configuration message received from the mobile wireless communication network;
determining a second frequency from a second reference signal received from the mobile wireless communication network;
computing a second timing advance value based on a first timing advance value, the first determined frequency, and the second determined frequency, the first timing advance value received as part of a control message, wherein computing the second timing advance value comprises computing a difference between a first time and a second time, the first time associated with a time when the first timing advance value is received, and the second time associated with a time when an uplink signal is transmitted; and
transmitting, to the mobile wireless communication network, an uplink signal using the second timing advance value.
12 . The method of claim 11 , further comprising receiving an indication that the second reference signal is not altered for a Doppler pre-compensation, the Doppler pre-compensation comprising a frequency shift in a transmitter.
13 . The method of claim 11 , further comprising computing the second timing advance value by computing a ratio of the second determined frequency to the first determined frequency.
14 . The method of claim 11 , further comprising computing the second timing advance value as a function of the first timing advance value plus a delta timing advance value, wherein:
the delta timing advance value is equal to two times a coefficient times a time difference value;
the coefficient comprises a ratio of the second frequency to the first frequency minus one;
the time difference value comprises a difference between a first time and a second time;
the first time is associated with a time when the first timing advance value is received; and
the second time is associated with a time when the uplink signal is transmitted.
15 . The method of claim 11 , further comprising computing the second time advance value according to a pre-defined time function that considers the first timing advance value, the first determined frequency, and the second determined frequency.
16 . The method of claim 11 , wherein the control message further comprises an expiration timer value such that transmitting the uplink signal using the second timing advance value is performed in response to determining that a first time associated with a time when the control message is received plus the expiration timer value is larger than a second time associated with a time when the uplink signal is transmitted.
17 . The method of claim 16 , further comprising transmitting the uplink signal using the second timing advance value in response to receiving at least one of:
an indication of a quasi-collocation relationship between the first reference signal and the second reference signal;
an indication of a quasi-collocation relationship between the first reference signal and the first timing advance value; and
an indication of a quasi-collocation relationship between the second reference signal and the first timing advance value.
18 . A base station, comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the base station to:
transmit, to a user equipment (“UE”) device, one of a first reference signal and a configuration message;
transmit, to the UE device, a second reference signal;
transmit, to the UE device, a control message comprising a first timing advance value; and
receive, from the UE device, an uplink signal that is transmitted using a second timing advance value, the second timing advance value determined based on:
a first frequency determined from one of the first reference signal and the configuration message;
a second frequency determined from the second reference signal; and
the first timing advance value, wherein the second timing advance value comprises a difference between a first time and a second time, the first time associated with a time when a first timing advance value is transmitted, and the second time associated with a time when an uplink signal is received.
19 . A processor for wireless communication, comprising:
at least one controller coupled with at least one memory and configured to cause the processor to:
determine a first frequency from one of a first reference signal received from a mobile wireless communication network and a configuration message received from the mobile wireless communication network;
determine a second frequency from a second reference signal received from the mobile wireless communication network;
compute a second timing advance value based on a first timing advance value, the first determined frequency, and the second determined frequency, the first timing advance value received as part of a control message, wherein computing the second timing advance value comprises computing a difference between a first time and a second time, the first time associated with a time when the first timing advance value is received, and the second time associated with a time when an uplink signal is transmitted; and
transmit, to the mobile wireless communication network, an uplink signal using the second timing advance value.