Method and device for estimating time and frequency offsets in communication system
The present disclosure relates to: a communication technique merging IoT technology with a 5G communication system for supporting a data transmission rate higher than that of a 4G system; and a system therefor. The present disclosure can be applied to intelligent services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security- and safety-related services, and the like), emergency communication services (emergency rescue signal transmission services), and the like on the basis of 5G communication technology, IoT-related technology and satellite communication. Proposed in the present disclosure is a method for performing a correlation operation on the basis of a reception signal and a PRACH preamble, and estimating a frequency offset on the basis of a first peak value and/or a second peak value in accordance with the correlation operation result.
1 . A method of a network entity in a wireless communication system, the method comprising:
receiving, from a user equipment (UE) via a satellite, a physical random access channel (PRACH) preamble;
obtaining, based on a correlation operation, correlation values for the PRACH preamble and identifying a first peak value that includes a largest value among the correlation values and a second peak value that includes a second largest value among the correlation values;
estimating a frequency offset based on the first peak value, the second peak value, and a length of the PRACH preamble; and
transmitting, to the UE via the satellite, the frequency offset, a unit of the frequency offset, and a change rate of the frequency offset,
wherein the unit of the frequency offset is determined based on a radius of a beam and a center frequency provided by the satellite, and
wherein the change rate of the frequency offset is a variation in the frequency offset to be applied at a specific time.
2 . The method of claim 1 , further comprising: transmitting, to the UE via the satellite, a signal obtained, by correcting a frequency, based on the frequency offset during a communication with the UE via the satellite.
3 . The method of claim 1 , wherein the first peak value is a value with a largest absolute value among the correlation values and the second peak value is a value with a second largest absolute value among the correlation values.
4 . The method of claim 1 , further comprising:
transmitting, via a medium access control control element (MAC CE) or a radio resource control (RRC) signaling, at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset to the UE via the satellite.
5 . The method of claim 1 , further comprising:
transmitting, to the UE via the satellite, downlink control information (DCI) including at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset.
6 . The method of claim 1 , further comprising:
transmitting, to the UE via the satellite, a random access response (RAR) message or a message B (msg B) including at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset.
7 . A method of a user equipment (UE) in a wireless communication system, the method comprising:
transmitting, to a network entity via a satellite, a physical random access channel, (PRACH) preamble; and
receiving, from the network entity via the satellite, a frequency offset, a unit of the frequency offset, and a change rate of the frequency offset,
wherein the frequency offset is estimated based on a first peak value, a second peak, and a length of the PRACH preamble,
wherein the first peak value comprises a largest value among correlation values obtained based on a correlation operation for the PRACH preamble, and a second peak value comprises a second largest value among the correlation values obtained based on the correlation operation for the PRACH preamble,
wherein the unit of the frequency offset is determined based on a radius of a beam and a center frequency provided by the satellite, and
wherein the change rate of the frequency offset is a variation in the frequency offset to be applied at a specific time.
8 . The method of claim 7 , further comprising:
transmitting, to the network entity via the satellite, a signal obtained, by correcting a frequency, based on the frequency offset during a communication with the network entity via the satellite.
9 . The method of claim 7 , wherein the first peak value is a value with a largest absolute value among the correlation values and the second peak value is a value with a second largest absolute value among the correlation values.
10 . The method of claim 7 , wherein the frequency offset, the unit of the frequency offset, and the change rate of the frequency offset are received via a medium access control control element (MAC CE) or a radio resource control (RRC) signaling.
11 . The method of claim 7 , wherein the frequency offset, the unit of the frequency offset, and the change rate of the frequency offset are received via downlink control information (DCI).
12 . The method of claim 7 , wherein the frequency offset, the unit of the frequency offset, and the change rate of the frequency offset are received via a random access response (RAR) message or a message B (msg B).
13 . A network entity in a wireless communication system, the network entity comprising:
a transceiver; and
a controller operably coupled with the transceiver, the controller configured to:
receive, from a user equipment (UE) via a satellite, a physical random access channel (PRACH) preamble,
obtain, based on a correlation operation, correlation values for the PRACH preamble and identify a first peak value that includes a largest value among the correlation values and a second peak value that includes a second largest value among the correlation values,
estimate a frequency offset based the first peak value, the second peak value, and a length of the PRACH preamble, and
transmit, to the UE via the satellite, the frequency offset, a unit of the frequency offset, and a change rate of the frequency offset,
wherein the unit of the frequency offset is determined based on a radius of a beam and a center frequency provided by the satellite, and
wherein the change rate of the frequency offset is a variation in the frequency offset to be applied at a specific time.
14 . The network entity of claim 13 , wherein the controller is further configured to transmit, to the UE via the satellite, a signal obtained, by correcting a frequency, based on the frequency offset during a communication with the UE via the satellite.
15 . The network entity of claim 13 , wherein the first peak value is a value with a largest absolute value among the correlation values and the second peak value is a value with a second largest absolute value among the correlation values.
16 . The network entity of claim 13 , wherein the controller is further configured to:
transmit, via medium access control control element (MAC CE) or radio resource control (RRC) signaling, at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset to the UE via the satellite.
17 . The network entity of claim 13 , wherein the controller is further configured to:
transmit, to the UE via the satellite, downlink control information (DCI) including at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset.
18 . The network entity of claim 13 , wherein the controller is further configured to:
transmit, to the UE via the satellite, a random access response (RAR) message or a message B (msg B) including at least one of the frequency offset, the unit of the frequency offset, or the change rate of the frequency offset.
19 . A user equipment (UE) in a wireless communication system, the UE comprising:
a transceiver; and
a controller operably coupled with the transceiver, the controller configured to:
transmit, to a network entity via a satellite, a physical random access channel (PRACH) preamble, and
receive, from the network entity via the satellite, a frequency offset, a unit of the frequency offset, and a change rate of the frequency offset,
wherein the frequency offset is estimated based on a first peak value, a second peak value, and a length of the PRACH preamble,
wherein the first peak value comprises a largest value among correlation values obtained based on a correlation operation for the PRACH preamble, and the second peak value comprises a second largest value among the correlation values obtained based on the correlation operation for the PRACH preamble,
wherein the unit of the frequency offset is determined based on a radius of a beam and a center frequency provided by the satellite, and
wherein the change rate of the frequency offset is a variation in the frequency offset to be applied at a specific time.
20 . The UE of claim 19 , wherein the controller is further configured to:
transmit, to the network entity via the satellite, a signal obtained, by correcting a frequency, based on the frequency offset during a communication with the network entity via the satellite.