Timing advance for satellite-based communications
Various arrangements are presented for using an estimated timing advance for user equipment communications. A location of an instance of user equipment may be determined. A first estimated distance between the user equipment and a communication satellite may be determined using the determined location of the user equipment and an estimated satellite location. A second estimated distance between the communication satellite and a communication network gateway may be determined. An estimated timing offset using the calculated first estimated distance and the determined second estimated distance may be determined. An uplink data frame may be transmitted by the user equipment to the satellite such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset.
1. A method for using an estimated timing advance for user equipment communications, the method comprising:
determining, by user equipment, a location of the user equipment using a global navigation satellite system;
calculating, by the user equipment, a first estimated distance between the user equipment and a communication satellite using the determined location of the user equipment and an estimated satellite location, wherein the estimated satellite location indicates an estimated orbital location of the communication satellite;
determining, by the user equipment, a second estimated distance between the communication satellite and a communication network gateway, wherein communications between the user equipment and a communication network are to be routed through the communication network gateway and the communication satellite;
calculating, by the user equipment, an estimated timing offset using the calculated first estimated distance and the determined second estimated distance;
transmitting, by the user equipment, to the communication satellite, an uplink data frame such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset;
receiving, by the user equipment, a TA command that comprises a timing advance (TA) value to the user equipment transmitting by the communication network gateway via the communication satellite;
adjusting, by the user equipment, the calculated estimated timing offset based on the received TA value to create a corrected TA value; and
transmitting, by the user equipment, to the communication satellite, data such that a timing of transmission of the data is based on the corrected TA value.
2. The method for using the estimated timing advance for the user equipment communications of claim 1 , wherein the uplink data frame transmitted to the communication satellite comprises a physical random access channel (PRACH) preamble.
3. The method for using the estimated timing advance for the user equipment communications of claim 2 , further comprising:
determining, by the communication network gateway, an amount of timing error due to the first estimated distance and the second estimated distance being estimated;
determining, by the communication network gateway, the timing advance (TA) value based on the amount of timing error; and
transmitting, by the communication network gateway, a timing advance command that comprises the TA value to the user equipment via the communication satellite.
4. The method for using the estimated timing advance for the user equipment communications of claim 3 , wherein the TA value is twelve bits in length.
5. The method for using the estimated timing advance for the user equipment communications of claim 4 , wherein the TA value has a defined maximum value of 3846.
6. The method for using the estimated timing advance for the user equipment communications of claim 3 , wherein the TA value allows for a timing correction of less than 2.5 ms.
7. The method for using the estimated timing advance for the user equipment communications of claim 1 , wherein the communication satellite is in geosynchronous orbit of the earth.
8. The method for using the estimated timing advance for the user equipment communications of claim 7 , wherein a maximum amount of error of a total distance is 100 km, wherein the total distance is the calculated first estimated distance summed with the determined second estimated distance.
9. The method for using the estimated timing advance for the user equipment communications of claim 1 , wherein determining the second estimated distance between the communication satellite and the communication network gateway comprises accessing the second estimated distance from a local data storage arrangement.
10. The method for using the estimated timing advance for the user equipment communications of claim 9 , wherein determining the second estimated distance between the communication satellite and the communication network gateway comprises receiving a system information broadcast message that indicates the second estimated distance.
11. The method for using the estimated timing advance for the user equipment communications of claim 1 , further comprising:
accessing locally-stored orbital information of the communication satellite, wherein the communication satellite is in low earth orbit (LEO) or middle earth orbit (MEO); and
calculating the estimated satellite location based on the locally-stored orbital information.
12. The method for using the estimated timing advance for the user equipment communications of claim 1 , wherein the communication network gateway comprises a gNodeB.
13. A device for using an estimated timing advance for satellite-based communications, the device comprising:
a satellite antenna for communicating directly with a communication satellite that relays communications to a satellite gateway system;
a global navigation satellite system (GNSS) component; and
one or more processors in communication with the satellite antenna and the GNSS component, the one or more processors configured to:
determine a location of the device using the GNSS component;
calculate a first estimated distance between the device and the communication satellite using the determined location of the device and an estimated satellite location, wherein the estimated satellite location indicates an estimated orbital location of the communication satellite;
determine a second estimated distance between the communication satellite and a communication network gateway, wherein communications between the device and a communication network are to be routed through the communication network gateway and the communication satellite;
calculate an estimated timing offset using the calculated first estimated distance and the determined second estimated distance;
transmit, to the communication satellite, via the satellite antenna, an uplink data frame such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset;
receive a TA command that comprises a timing advance (TA) value transmitted by the communication network gateway via the communication satellite;
adjust the calculated estimated timing offset based on the received TA value to create a corrected TA value; and
transmit to the communication satellite, data such that a timing of transmission of the data is based on the corrected TA value.
14. The device for using the estimated timing advance for satellite-based communications of claim 13 , wherein the uplink data frame transmitted to the communication satellite comprises a physical random access channel (PRACH) preamble.
15. A system for using an estimated timing advance for satellite-based communications, the system comprising:
a communication satellite;
a communication network gateway system that communicates with the communication satellite; and
user equipment, comprising:
a satellite antenna for communicating with the communication satellite that relays communications to the communication network gateway system;
a global navigation satellite system (GNSS) component; and
one or more processors in communication with the satellite antenna and the GNSS component, the one or more processors configured to:
determine a location of the user equipment using the GNSS component;
calculate a first estimated distance between the user equipment and the communication satellite using the determined location of the user equipment and an estimated satellite location, wherein the estimated satellite location indicates an estimated orbital location of the communication satellite;
determine a second estimated distance between the communication satellite and the communication network gateway system, wherein communications between the user equipment and a communication network are to be routed through the communication network gateway system and the communication satellite;
calculate an estimated timing offset using the calculated first estimated distance and the determined second estimated distance; and
transmit, to the communication satellite, via the satellite antenna, an uplink data frame such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset;
receive a TA command that comprises a timing advance (TA) value transmitted by the communication network gateway system via the communication satellite;
adjust the calculated estimated timing offset based on the received TA value to create a corrected TA value; and
transmit to the communication satellite, data such that a timing of transmission of the data is based on the corrected TA value.
16. The system of claim 15 , wherein the communication network gateway system is configured to:
determine an amount of timing error due to the first estimated distance and the second estimated distance being estimated;
determine the timing advance (TA) value based on the amount of timing error; and
transmit the TA command that comprises the TA value to the user equipment via the communication satellite.
17. The system of claim 16 , wherein the communication satellite is in geosynchronous orbit of the earth and a maximum amount of error of a total distance is 100 km, wherein the total distance is the calculated first estimated distance summed with the determined second estimated distance.