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EP-4738726-A1 - EXCHANGE OF SATELLITE INFORMATION FOR TRANSFERRING USER DATA

EP4738726A1EP 4738726 A1EP4738726 A1EP 4738726A1EP-4738726-A1

Abstract

The invention provides a method of processing user data in a first satellite of a Non-Terrestrial Network, NTN, wherein the first satellite stores user data from at least one user equipment located in a first cell served by the first satellite, the method comprising the following steps: - transmitting (205) a request message to a second satellite of the NTN, the request message requesting satellite information related to a second satellite; - receiving (207) a response message from the second satellite, the response message comprising satellite information related to the second satellite; - deciding (217) to transfer a set of stored user data to the second satellite, based at least on the satellite information related to the second satellite; - transferring (218) the set of stored user data to the second satellite.

Inventors

  • PANAITOPOL, DORIN
  • RONTEIX-JACQUET, Flavien
  • EL JAAFARI, Mohamed
  • CHUBERRE, NICOLAS
  • FINE, JEAN-YVES

Assignees

  • THALES DIS FRANCE SAS
  • THALES

Dates

Publication Date
20260506
Application Date
20250312

Claims (14)

  1. A method of processing user data in a first satellite (100.1) of a Non-Terrestrial Network, NTN, wherein the first satellite stores user data from at least one user equipment (110.1) located in a first cell (101) served by the first satellite, the method comprising the following steps: - transmitting (205) a request message to a second satellite of the NTN, the request message requesting satellite information related to a second satellite (100.2); - receiving (207) a response message from the second satellite, the response message comprising satellite information related to the second satellite; - deciding (217) to transfer a set of stored user data to the second satellite, based at least on the satellite information related to the second satellite; - transferring (218) the set of stored user data to the second satellite.
  2. The method according to claim 1, further comprising establishing (202) an Inter-Satellite Link (160.12), ISL, between the first satellite (100.1) and the second satellite (100.2) before transmitting the request message.
  3. The method according to claim 2, further comprising, after establishing (202) the ISL (160.12) between the first satellite (100.1) and the second satellite (100.2), activating (203) a 5G New Radio, NR, Xn interface, or a Long Term Evolution, LTE, X2 interface, between the first satellite and the second satellite, wherein the request message is transmitted (205) on the X2 or Xn interface and wherein the response message is received (207) on the X2 or Xn interface.
  4. The method according to one of the preceding claims, wherein the first satellite (100.1) decides (217) to transfer the set of user data to the second satellite (100.2) if at least one predetermined overload condition and/or predetermined delay condition is met, and if no link to a terrestrial gateway (120) is accessible to the first satellite.
  5. The method according to one of the preceding claims, wherein the satellite information related to the second satellite (100.2) is representative of storage and/or processing capabilities of the second satellite, of an inter-satellite link (160.12), ISL, between the first satellite and the second satellite, and/or of a link (150.2) between the second satellite and a terrestrial gateway (120).
  6. The method according to claim 5, wherein the satellite information related to the second satellite comprises one or several of the following information: - an updated ISL time interval of the ISL (160.12) between the first satellite (100.1) and the second satellite (100.2); and/or the throughput capacity of the link and/or - at least one link time interval describing an availability of a link (150.2) between the second satellite and a terrestrial gateway (120); and/or - at least one satellite capacity information, describing maximum or current storage capacity or maximum or current processing capacities of the second satellite; and/or - a satellite type of the second satellite; and/or - position and speed information related to the second satellite; and/or - feeder link latency indicating a latency associated with the link between the second satellite and the terrestrial gateway; and/or - a current load and/or used capacity of the second satellite. and/or amount of data received (and/or to be transmitted) from (to) the second satellite.
  7. The method according to one of the preceding claims, further comprising, storing (208), by the first satellite (100.1), the satellite information related to the second satellite (100.2) in a connectivity table.
  8. The method according to claim 7, further comprising, after receiving (207) the response message comprising the satellite information related to the second satellite (100.2), receiving (215) an update message comprising satellite information update related to the second satellite, and updating (216) the satellite information related to the second satellite stored in the connectivity table based on the satellite information update.
  9. The method according to claim 7 or 8, wherein the first satellite (100.1) transmits (205) request messages to a plurality of other satellites including the second satellite (100.2), receives (207) response messages from the plurality of other satellite, each response message comprising satellite information related to the other satellite from which the response message is received, and wherein the first satellite stores (208) the received satellite information for the plurality of other satellites in the connectivity table.
  10. The method according to claim 9, wherein the decision (217) to transfer user data to the second satellite (100.2) comprises selecting the second satellite among the plurality of other satellites based on the satellite information stored in the connectivity table.
  11. The method according to one of the preceding claims, wherein the decision (217) to transfer user data to the second satellite (100.2) comprises a comparison of satellite information related to the first satellite with the satellite information related to the second satellite.
  12. A computer program comprising instructions arranged for implementing the method according to one of claims 1 to 11, when said instructions are executed by a processor (301).
  13. A satellite (100.1) of a Non-Terrestrial Network, NTN, comprising a memory (302) storing user data from at least one user equipment (110.1) located in a first cell (101) served by the first satellite, the satellite further comprising a processor (301) configured for: - transmitting, via a radio interface or optical interface (304), a request message to a second satellite (100.2) of the NTN, the request message requesting satellite information related to another satellite; - receiving, via the radio interface or optical interface, a response message from the other satellite, the response message comprising satellite information related to the second satellite; - deciding to transfer a set of stored user data to the second satellite, based at least on the satellite information related to the other satellite; - transferring, via the radio interface or optical interface, the set of stored user data to the other satellite.
  14. A telecommunications system comprising several satellites (100.1; 100.2; 100.3) according to claim 13, and at least one terrestrial gateway (120) configured to communicate with the satellites via respective radio links, wherein the terrestrial gateway is connected to a core network (121) of a non-terrestrial and terrestrial network.

Description

This invention is related to the field of telecommunications network, in particular of Non-Terrestrial Network(s) (NTN). The invention is useful in particular, but not exclusively, in the context of offloading or transfer of user data from a first satellite to a second satellite in an NTN to optimize resources in the NTN. Non-Terrestrial Networks may be based on satellites, high altitude platforms (HAPS) or other aircraft systems located at high altitudes, or even drones/UAV, which may be used as relay stations or base stations of a telecommunications network. In particular, NTN can be used starting with the fifth Generation mobile communication system, 5G (and future generations such as 6G), telecommunications network in cooperation with a 5G Terrestrial Network, 5G TN. Currently 5G NTN has two potential trends: for NB-loT/loT-like communications (using LTE technology starting with Release-18) or for smartphones and VSAT broadband communications (using 5G NR New Radio technology starting with Releases 17 and 18). Satellites can therefore be used as relay nodes (in the case of transparent satellites) or as base stations, called gNB in a 5G-like network (in the case of regenerative satellites), or eNB in an LTE-like network, potentially xNB for 6G networks. The use of NTN satellites enable to expand the coverage of 5G TN, as some areas cannot be served by the 5G TN, such as oceans or isolated rural areas for example. Some NTN satellites, called Store and Forward, S&F, satellites, are able to receive user data from user equipments, UEs, store the data and forward it/transfer the user data to the 5G ground system via a link with a terrestrial gateway, said link being called "feeder link" in what follows. In several applications, 5G NTN can be interfaced with the 5G TN (e.g. at core network level) allowing data transfer/communication between 5G NTN system/UE and 5G TN system/UE. User equipments encompass cellular devices such as mobile phones and other SIM-enabled devices such as tablets, smartwatches and Internet of Things, IoT, devices, and/or High Power UEs (HPUEs) and/or VSAT (Very Small Antenna Aperture) equipments mounted on drones/airplanes/vehicles etc.. The terrestrial gateway is linked to the 5G or 4G core network, so as to be able to forward the user data received from the satellites, to the respective recipients of the user data, via the TN. S&F satellites are therefore regenerative satellites that can form base stations of a New Generation Radio Access Network, NG RAN. However, because the number of terrestrial gateways (GWs) is currently low, and/or because some satellites may be in relative motion compared to earth and/or because radio conditions may vary over time, the feeder link of a satellite that is non stationary (NGSO satellite) is intermittent (e.g. the satellite is not always connected to a GW). This causes, that the satellite cannot forward the user data that is accumulating/stored (e.g. in the satellite memory), to a terrestrial gateway, during a given period where the feeder link is not available. In some cases, depending on the geographical zone (or area), the user traffic, the user density and coverage of the satellite, this may cause an overload of the satellite that is not able to receive new user data because its storage capacity is full. This also increases the delay associated with the forwarding of the user data, which, in some applications, may deteriorate the quality of service. In some other cases, due to energy limitations, memory or CPU, data cannot be stored indefinitely while waiting for a feeder link availability. In such case, satellite (current or future) available/remaining energy can also be part of the required inputs for a more reliable and more optimized routing between satellites or/and between satellites and ground segment to improve the network performance. There is therefore a need to improve the quality of service for UEs in radiocommunication with an S&F satellite of an NTN, for processing user data, storing it and/or transferring it to another network (TN or NTN) or another NTN system component. The invention aims at improving the situation. A first aspect of the invention concerns a method of processing user data in a first satellite of a Non-Terrestrial Network, NTN, wherein the first satellite stores user data from at least one user equipment located in a first cell served by the first satellite, the method comprising the following steps: transmitting a request message to a second satellite of the NTN, the request message requesting satellite information related to a second satellite;receiving a response message from the second satellite, the response message comprising satellite information related to the second satellite;deciding to transfer a set of stored user data to the second satellite, based at least on the satellite information related to the second satellite;transferring the set of stored user data to the second satellite. Therefore, satellit