Method for validating the positioning of a user terminal in a 5G cell network

Abstract

The invention relates to a 5G communication system comprising a 5G cellular radio network, each cell of said 5G cellular radio network comprising at least one base station, each base station being adapted to communicate with a 5G-compatible user terminal (UE). The communication system comprises a satellite (Sat), said satellite (Sat) being adapted to exchange service frames (TS) with the user terminal (UE), a gateway (GW), said gateway (GW) being adapted to exchange feeder link frames (TLF) with the satellite (Sat), a 5G core network (5GC), said core network (5GC) being connected to the gateway (GW), said core network (5GC) being capable of communicating with the base stations. The user terminal (UE) is capable of communicating at any given time with several base stations, referred to as proximity base stations (gNB1,…, gNBi, …, gNBn). Figure for the abstract: Fig. 4

Description

Title of the invention: Method for validating the positioning of a user terminal in a 5G cell network Technical field

[0001] The present invention relates to the implementation of 5G communications between a terminal (called User Equipment in English or UE) using and a central network (called 5G Core in English or 5GC) via at least one communication satellite. Prior art

[0002] Satellite systems for user terminals are currently proprietary and have little or no interoperability between different satellite systems or with terrestrial mobile networks. Existing user terminals and network equipment are expensive and specific. This limits them to niche markets and does not allow them to create a solution for the mainstream market.

[0003] The 3GPP (3rd Generation Partnership Project) mobile network standardization organization is attempting to address this problem by proposing modifications to the 5G standard, known as the fifth generation of mobile networks, to make it compatible from a satellite perspective. Modifications are then expected across all system components. To this end, a new version of the 3GPP standard is being developed in version 17 (i.e. Release-17 or Rel-17) to enable the use of 5G via satellite within the framework of a 3GPP NTN (Non-Terrestrial Networks) working group. This version provides for modifications to the various components of the communication system. It is known that a communication system for 5G communication includes a core network and at least one base station belonging to a 5G cell.In a satellite system, the communication system also comprises at least one gateway arranged between the satellite and the core network. The communication system thus enables 5G communication between user terminals and said core network.

[0004] The user terminal in communication with the core network is present in a cell of the 5G cell network. In order to ensure certain functionalities, such as, for example, billing functionalities, it is necessary to have good knowledge of the position of the user terminal in the 5G cell network, at all times.

[0005] It is known to use at the user terminal level, the coordinates of a satellite positioning system called GNSS coordinates for Geolocation and Navigation by a Satellite System. By GNSS, we understand any system or combination of satellite navigation systems such as, for example, GPS, GALILEO, BEIDOU, GLONASS, EGNOS, NavIC, QZSS (or Michibiki), etc. The user terminal thus sends its GNSS coordinates back to the central network. The user terminal also uses its GNSS coordinates / information to synchronize with the 5G NTN satellite network (known as Non-Terrestrial Networks in English or NTN), for example to perform Doppler pre-compensation and / or a Timing Advance procedure.

[0006] However, the user terminal can easily misleadingly modify its geographical position, i.e. the measurement carried out or the GNSS measurement report sent to the core network. Therefore, a 5G network cannot consider the GNSS position transmitted to it by the user terminal as totally reliable. This 5G network must therefore have a verification / validation mechanism by the network. This verification mechanism is necessary to know the position of the user terminal in order to apply the correct routing policy and the correct tariff. This mechanism is also necessary to allow legal interceptions (Lawful Interception in English) in order to be able to intercept the user terminal by a competent authority of the country in which said user terminal is located. Finally, such a verification mechanism makes it possible to refuse access by satellite e.g. in countries which are not served by the satellite operator.

[0007] To carry out a verification mechanism at the 5G network level, it is known to use conventional positioning techniques, such as positioning techniques used for terrestrial networks. It is thus possible to use positioning signals or any other type of pilot signal. However, the problem is that satellite cells are very large and the geographical areas are not necessarily covered by several cells at the same time as in a terrestrial cellular radio network. It is also possible to introduce new pilots (called Service Link in English or SL), in particular reference signals for positioning (called Positioning Reference Signals in English or PRS) and measurement reports from user terminals UEs on the PRS, or a use of SRS pilots (called Sounding Reference Signals) transmitted by UE to the satellite and / or the satellite access network.However, these solutions are difficult to implement, especially if there is only one available satellite and / or only one NTN cell covering the service area. In addition, in version 17 of the 3GPP standard, the user terminal pre-compensates the Timing Advance and the Doppler in UpLink and this before and after the first transmission and / or initial access to the satellite. GNSS information and ephemeral communication satellites are used. However, it is not possible to use conventional location methods unless a power level received by several 5G NR (so-called "New Radio" satellites) is required, if . several of these satellites cover the same area. Finally, such a solution does not solve the validation issues for a geostationary deployment with cells / spots of about e.g. 300-500 km width on the ground. There are also other known solutions for satellite communications, such as proprietary solutions e.g. Iridium with an "Earth Moving Cell" implementation. For this type of implementation, the beams / cells / spots on the ground move with the satellite, the terminals stay relatively short time in the cell (especially in low altitude constellations with satellites moving at high speed) and it is possible to have an estimate of the terminal's position at the moment the terminal leaves the cell / connects to another cell, even if the solution is not very precise.However, in the case of LEO / MEO satellites, it is also possible to use an active antenna on the satellite to cover a single area on the ground ("Earth Fixed Cell" as opposed to "Earth Moving Cell"), but the cells / spots on the ground still have a significant width of around 50-90 km and the positioning accuracy remains very low. No solution is available today for 5G NTN technologies of the "Earth Fixed Cell" type.

[0008] Also known are the LPP and NRPPa protocols. These protocols are described in different versions of the 3GPP standard such as: - 3GPP TS 23.271 V15.2.0 (2019-12), Functional stage 2 description of Location Services (LCS) (Release 15); - 3GPP TS 23.273 V16.2.0 (2019-12), 5G System (5GS) Location Services (LCS); Stage 2 (Release 16); - 3GPP TS 38.305 V15.5.0 (2019-12), Stage 2 functional specification of User Equipment (UE) positioning in NG-RAN (Release 15); - 3GPP TS 38.455 V15.2.1 (2019-01), NR Positioning Protocol A (NRPPa); (Release 15); - 3GPP TR 38.855 V16.0.0 (2019-03), Study on NR positioning support (Release 16); - 3GPP TR 38.856 V16.0.0 (2019-12) Study on local NR positioning in NG-RAN (Release 16).

[0009] These LPP and NRPPa protocols are also described in TS 37.355 and TS 38.455.

[0010] The operation of all or part of these protocols is illustrated in particular in Figures 1 to 3.

[0011] There is therefore a need to improve the mechanism for verifying the GNSS coordinates of the user terminal in a 5G network while minimizing the impacts on the different equipment used. Statement of the invention

[0012] The present invention aims to at least partially address this need.

[0013] More particularly, the invention aims to improve the determination of the position of a user terminal in a 5G cell network.

[0014] For this purpose, a first object of the invention relates to a method for validating a positioning of a 5G-compatible user terminal in a 5G cell network. The user terminal is adapted to exchange service frames with a satellite. The satellite is adapted to exchange feeder link frames with a gateway. The gateway is connected to a 5G core network, each 5G cell of the 5G network comprising at least one base station, each base station being able to communicate with the 5G core network. The user terminal is able to communicate at a given time with several base stations of the 5G cells, called proximity base stations.The validation method comprises a step of determining first positioning data of the user terminal, said first positioning data being a GNSS position of the user terminal, said first positioning data being sent by the user terminal to the 5G core network via the satellite. The validation method comprises a step of sending by the user terminal second positioning data of the user terminal to the 5G core network, said second positioning data being based on all or part of propagation channel measurements carried out by the user terminal on the proximity base stations, said sending step being carried out via the satellite.The validation method comprises a step of sending by the proximity base stations third positioning data of the user terminal to the 5G core network, said third positioning data being based on propagation channel measurements carried out by the proximity base stations on the user terminal, said sending step being carried out without going through the satellite. Finally, the method comprises a step of comparing, in the 5G core network, the second positioning data with the third positioning data, the first positioning data of the user terminal being validated if the second positioning data are compatible with the third positioning data.

[0015] The 5G core network thus compares the second positioning data with the third positioning data and decides whether the user terminal can be accepted into the 5G network or not.

[0016] In a particular embodiment, the second positioning data are measurements of the propagation channels carried out by the user terminal on the transmissions of one or more proximity base stations.

[0017] In a particular embodiment, the second positioning data are particular secret keys of the user terminal, said particular secret keys being calculated from the propagation channels by the user terminal on the emissions of the nearby base stations.

[0018] In a particular embodiment, the second positioning data is a global secret key calculated from the particular secret keys.

[0019] The global secret key corresponds to an electromagnetic fingerprint. Once the authentication of the positioning of the user terminal is carried out, the user terminal and / or the satellite and / or the gateway can use the global secret key to secure the link.

[0020] In a particular embodiment, the third positioning data are the measurements of the propagation channels by the proximity base stations on the transmissions of the user terminal.

[0021] In a particular embodiment, the third positioning data are particular secret keys of the proximity base stations, said secret keys being calculated from the channel measurements of said proximity stations on the transmissions of the user terminal.

[0022] In a particular embodiment, the third positioning data is a global base station secret key calculated from the particular secret keys.

[0023] In a particular embodiment, the secret keys are added to LPP / NRPPa protocols in their transmission to the 5G core network.

[0024] In a particular embodiment, the method initially comprises a step of authenticating the user terminal in the 5G central network.

[0025] Another object of the invention relates to a 5G communication system comprising: - a 5G cell network, each cell of said 5G cell network comprising a base station, each base station being adapted to communicate with a 5G compatible user terminal; - a satellite, said satellite being adapted to exchange service frames with the user terminal; - a gateway, said gateway being adapted to exchange feeder link frames with the satellite; - a 5G core network, said core network being connected to the gateway, said core network being able to communicate with the base stations; - said user terminal being able to communicate at a given time with several base stations, called proximity base stations; said 5G communication system being capable of implementing the steps of a method for validating a positioning of the user terminal in the 5G cell network, according to the invention.

[0026] Another subject of the invention relates to a method for exchanging first positioning data and second positioning data intended to be implemented by a 5G compatible user terminal for validation of a positioning of said user terminal in a 5G cell network, said user terminal being adapted to exchange service frames with a satellite, said satellite being adapted to exchange feeder link frames with a gateway, said gateway being connected to a 5G core network, each 5G cell of the 5G cell network comprising a base station, each base station being able to communicate with the 5G core network, said user terminal being able to communicate at a given time with several base stations, called proximity base stations. The data exchange method comprises: - a step of determining the first positioning data of the user terminal, said first positioning data being a GNSS position of the user terminal, said first positioning data being sent by the user terminal to the 5G central network via the satellite; - a step of sending by the user terminal the second positioning data of the user terminal to the 5G central network, said second positioning data being based on all or part of the propagation channel measurements carried out by the user terminal on the proximity base stations, said sending step being carried out via the satellite, said second positioning data being able to be compared with third positioning data, said third positioning data being adapted to be sent by the proximity base stations without going through the satellite, said third positioning data being based on propagation channel measurements carried out by the proximity base stations on the user terminal,the first positioning data of the user terminal being validated if the second positioning data is compatible with the third positioning data.

[0027] Another object of the invention relates to a 5G compatible user terminal, said user terminal being capable of implementing the steps of a method for exchanging first positioning data and second positioning data according to the invention for validating a positioning of said user terminal in a 5G cell network.

[0028] Another subject of the invention relates to a computer program comprising program instructions usable by a 5G compatible user terminal according to the invention, which when executed or interpreted by said user terminal trigger the implementation of a method for exchanging first positioning data and second positioning data according to the invention for a validation of the positioning of said user terminal in a 5G cell network.

[0029] Another subject of the invention relates to a method for exchanging third positioning data intended to be implemented by a base station for validating a positioning of a 5G compatible user terminal in a 5G cell network, said base station, called proximity base station, being able to communicate at a given instant with said user terminal, said user terminal being adapted to exchange service frames with a satellite, said satellite being adapted to exchange feeder link frames with a gateway, said gateway being connected to a 5G central network, the base station being able to communicate with said 5G central network. The data exchange method comprises: - a step of sending third partial positioning data to the 5G core network without going through the satellite, said third positioning data being based on propagation channel measurements carried out by the base station, said third partial positioning data being adapted to be combined with third partial positioning data based on propagation channel measurements carried out by other nearby base stations in communication with the user terminal at the given time to form third positioning data, said third positioning data being adapted to be compared with second positioning data, said second positioning data having been sent by the user terminal to the 5G core network via the satellite,said second positioning data being based on the propagation channel measurements carried out by the user terminal on the proximity base stations, first positioning data of the user terminal in the 5G cell network being validated if the second positioning data is compatible with the third positioning data, said first positioning data being a GNSS position of the user terminal, said first positioning data being sent by the user terminal to the 5G core network via the satellite.

[0030] Another object of the invention relates to a base station capable of implementing the steps of a method for exchanging third positioning data according to the invention for validating the positioning of a user terminal in a 5G cell network.

[0031] Another subject of the invention relates to a computer program comprising program instructions usable by a base station according to the invention, which when executed or interpreted by said base station trigger the implementation of a method for exchanging third positioning data. according to the invention for validating the positioning of a user terminal in a 5G cell network.

[0032] Another subject of the invention relates to a method for processing first positioning data, second positioning data and third positioning data of a 5G compatible user terminal in a 5G cell network, said user terminal being adapted to exchange service frames with a satellite, said satellite being adapted to exchange feeder link frames with a gateway, said gateway being connected to a 5G core network, each 5G cell of the 5G cell network comprising a base station, each base station being able to communicate with the 5G core network, said user terminal being able to communicate at a given time with several base stations of the 5G cells, called proximity base stations. The processing method comprises: - a step of receiving the first positioning data from the user terminal, said first positioning data being a GNSS position of the user terminal, said first positioning data being sent by the user terminal via the satellite; - a step of receiving second positioning data from the user terminal, said second positioning data being based on all or part of the propagation channel measurements carried out by the user terminal on the proximity base stations, said second positioning data being sent by the user terminal via the satellite; - a step of receiving third positioning data, said third positioning data being based on propagation channel measurements carried out by the proximity base stations on the user terminal, said sending step being carried out by the proximity base stations without going through the satellite; - a step of comparing the second positioning data with the third positioning data, the first positioning data of the user terminal being validated if the second positioning data are compatible with the third positioning data.

[0033] Another object of the invention relates to a 5G central network capable of implementing the steps of a method for processing positioning data according to the invention for validating the positioning of a user terminal in a 5G cell network.

[0034] Another subject of the invention relates to a computer program comprising program instructions usable by a 5G access network according to the invention, which when executed or interpreted by said 5G access network trigger the implementation of a method for processing positioning data according to the invention for validating the positioning of a user terminal in a 5G cell network.

[0035] The present invention will be better understood on reading the detailed description of embodiments taken as non-limiting examples and illustrated by the appended drawings in which:

[0036] [Fig-1] [Fig.l] illustrates a software architecture of a communication system 5G according to the prior art;

[0037] [Fig.2] [Fig.2] illustrates data exchanges between elements of the software architecture of [Fig.l];

[0038] [Fig.3] [Fig.3] illustrates a method for determining a positioning of a user terminal via the software architecture of [Fig.l].

[0039] [Fig.4] [Fig.4] illustrates a 5G communication system according to the invention;

[0040] [Fig.5] [Fig.5] illustrates the steps of a positioning validation process of a user terminal implemented by the 5G communication system of [Fig.4] according to a first embodiment;

[0041] [Fig.6] [Fig.6] illustrates a Release 17 control plane and satellite architecture;

[0042] [Fig.7] [Fig.7] illustrates a first example of an organization of information SKG with 8-bit quantization per subcarrier;

[0043] [Fig.8] [Fig.8] illustrates a second example of an organization of information SKG with 4-bit quantization per subcarrier;

[0044] [Fig.9] [Fig.9] illustrates a third example of an organization of information SKG with 8-bit quantization per subcarrier;

[0045] [Fig. 10] [Fig. 10] illustrates a third example of an organization of a SKG information with 16-bit quantization per subcarrier;

[0046] [Fig. 11] [Fig. 11] illustrates the steps of a validation process for a positioning of a user terminal implemented by the 5G communication system of [Fig.4] according to a second embodiment;

[0047] [Fig. 12] [Fig. 12] illustrates the steps of a validation process for a positioning of a user terminal implemented by the 5G communication system of [Fig.4] according to a third embodiment;

[0048] [Fig. 13] [Fig. 13] illustrates a first example of modifications to the procedure E- CID within the framework of NRPPa TS 38.455;

[0049] [Fig. 14] [Fig. 14] illustrates a second example of modifications to the procedure E- CID within the framework of NRPPa TS 38.455;

[0050] [Fig. 15] [Fig. 15] illustrates a third example of modifications to the procedure E-CID within the framework of NRPPa TS 38.455;

[0051] [Fig. 16] [Fig. 16] illustrates examples of modification NRPPa TS 38.455;

[0052] [Fig. 17] [Fig. 17] illustrates a first example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355;

[0053] [Fig. 18] [Fig. 18] illustrates a second example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355;

[0054] [Fig. 19] [Fig. 19] illustrates a third example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355;

[0055] [Fig.20] [Fig.20] illustrates a first example of procedure modification if a measurement on LTE E-CID is carried out, according to LPP TS 37.355;

[0056] [Fig.21] [Fig.21] illustrates a second example of procedure modification if a measurement on LTE E-CID is carried out, according to LPP TS 37.355.

[0057] The invention is not limited to the embodiments and variants presented and other embodiments and variants will become clear to those skilled in the art.

[0058] [Fig.4] illustrates a 5G communication system 1 for 5G communication with a user terminal UE.

[0059] The 5G communication system comprises: - a 5G cell network; - proximity base stations (gNBl,..., gNBi, ..., gNBn); - a Sat satellite; - a GW gateway; - a gNB satcom base station; - a 5GC central network.

[0060] The 5G cell network comprises a plurality of 5G cells defining coverage areas where connection with the user terminal UE is possible. Each 5G cell comprises at least one base station adapted to transmit and receive data on said 5G cell. When the user terminal UE moves in the 5G cell network, it is connected, at a given moment, with a plurality of base stations of different 5G cells called proximity base stations gNBl,..., gNBi,..., gNBn.

[0061] It will be noted that the user terminal UE is 5G compatible and more particularly compatible with version no. 17 of the 3GPP standard so that this terminal has an NTN functionality (for “Non-Terrestrial Network” in English).

[0062] The communication system 1 also comprises the satellite Sat. This satellite Sat is suitable for exchanging service frames Ts with the user terminal UE. The satellite Sat is also suitable for exchanging feeder link frames TLF with the gateway GW. The satellite Sat is, for example, a satellite moving in a non-geostationary orbit called an NGSO satellite (for “Non-Geostationary Orbit” in English), such as a LEO satellite (for “Low-Earth Orbit” in English), vLEO (for “very Low-Earth Orbit” in English) or MEO satellite (for “Medium-Earth Orbit” in English). The reference point of this satellite moves relative to the proximity base stations gNBl,..., gNBi, ..gNBn and this delay is highly variable, for example it can be between 2 and 5 ms with a variation rate of up to 25 ppm in the case where the satellite is in an orbit at 600 km (LEO@600km). [Fig.6] illustrates a control plane ("Control Plane" in English or CP) and an architecture of the satellite Sat according to Release-17 5G NR. This architecture is compatible with the version TR 38.821 disclosing a CP 5G NR NTN protocol stack for a non-regenerative satellite (repeater satellite, with a relay at the RF level, "RF Repeater" or "Bend-pipe" satellite).

[0063] The GW gateway makes it possible to enable communication between a wired environment and the radio environment associated with the SAT satellite. Thus, the GW gateway is adapted to communicate with the 5GC core network. In the embodiment of [Fig.4], the GW gateway communicates with the 5G core network via the gNB satcom base station.

[0064] The 5GC central network here comprises an NGC module (for “Next Generation Core” in English) and which is connected to a public data network (PDN).

[0065] The user terminal UE is adapted to determine first positioning data Posl via communication with one or more satellites Sat. These first positioning data Posl correspond to a GNSS position of the user terminal UE. The first positioning data Posl are transmitted to the 5G core network via the satellite Sat.

[0066] The user terminal UE is also adapted to determine second positioning data Pos2. These second positioning data Pos2 are based on all or part of channel measurements carried out by the proximity base stations gNBl,..., gNBi,..., gNBn. The user terminal UE is thus capable of communicating with the different base stations via different radio channels i. The information CHi originating from a radio channel i may be the impulse response of the channel i or the values ​​of this response for certain multipaths only, the frequency response of the channel i or the values ​​of this response for certain subcarriers only. The information transmitted may be transmitted in a periodic, aperiodic, event-driven, etc. manner.

[0067] Each impulse response or frequency response of the radio channel can be evaluated on a given band configuration related to GSM, CDMA, HSDPA, HSUPA, LTE, WiMax, WiFi, 802.11 or other technology (not only 5G NR) when connected with the 5G Core.

[0068] It is also possible to consider operation with a non-roaming or roaming architecture / scenario.

[0069] Each impulse response or frequency response of the radio channel (single-path or multi-path) can be evaluated on a subcarrier, on several subcarriers, on a group of subcarriers (generally a multiple of 12 subcarriers).

[0070] The size of a subcarrier (e.g. 7.5 kHz, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz or 480 kHz) may change with numerology or depending on the technology used.

[0071] For a fiat fading type channel (in OFDM 5G, for example), the value of the channel CHi can be translated by a simple amplitude, which can be quantifiable on, for example, 8 bits, 16 bits, 32 bits, 64 bits, 128 bits or 256 bits.

[0072] The concept of subcarrier and variation of the received signal on a subcarrier is related to the OFDM waveform. This waveform results from orthogonal frequency division multiplexing. Cyclic prefix OFDM (CP-OFDM) technology has become the preferred choice for 5G NR.

[0073] In the context of cellular standards, "numerology" refers to the symbol duration and subcarrier spacing of the physical layer. 3GPP has established a flexible numerology that adjusts the spacing between orthogonal subcarriers and starts with the 15 kHz spacing of LTE technology.

[0074] [Fig.7] illustrates a first example of an organization of SKG information with quantification on 8 bits per subcarrier.

[0075] [Fig.8] illustrates a second example of an organization of SKG information with a quantification on 4 bits per subcarrier (16 values / subcarrier).

[0076] [Fig.9] illustrates a third example of an organization of SKG information with a quantification on 8 bits per subcarrier with an estimation on a multiple of 12 subcarriers SP / Resource Blocks RBs (fixed value) or possibly a multiple of 2 subcarriers out of 12.

[0077] [Fig. 10] illustrates a fourth example of an organization of SKG information with a quantization on 16 bits / subcarrier with an estimation on a multiple of 2 subcarriers out of 12 (1RB). In this alternative a “security key IE” (IE corresponds to “Information Element” in English, information element for the security key) on NG-AP is defined on 256 bits.

[0078] From its channel measurements on the emissions of the proximity base stations gNB 1,..., gNBi, ..., gNBn, the user terminal UE can determine particular secret keys SKG; associated respectively with the proximity base stations gNBl, ..., gNBi, ..., gNBn. These different secret keys are sent to the central network 5GC via the satellite Sat.

[0079] Preferably, the user terminal UE is able to determine a global secret key SKG calculated from the different particular secret keys SKG;. This global secret key SKG is, for example, a summation or concatenation of the different particular secret keys SKG;

[0080] It will be noted that when the user terminal UE transmits particular secret keys SKGi, the central network 5GC is able to reconstitute a global secret key SKG from said different particular keys SKG;.

[0081] The use of particular secret keys SKG; or a global secret key SKG makes it possible to limit the quantity of information sent via the Sat satellite to the central network 5GC.

[0082] It will be noted that in the transmission of the particular secret keys SKG;, it is possible to define new information elements in existing messages such as in the message pairs: - MEASUREMENT INITIATION REQUEST and MEASUREMENT INITIATION RESPONSE, or - MEASUREMENT UPDATE and MEASUREMENT REPORT, or - INFORMATION REQUEST and INFORMATION RESPONSE, or - INFORMATION UPDATE, or - MEASUREMENT REQUEST and MEASUREMENT RESPONSE.

[0083] It is also possible to create a new message for SKG global secret keys in message pairs: - SKG MEASUREMENT INITIATION REQUEST and SKG MEASUREMENT INITIATION RESPONSE, or - SKG MEASUREMENT UPDATE and SKG MEASUREMENT REPORT, or - SKG INFORMATION REQUEST and SKG INFORMATION RESPONSE, or - SKG INFORMATION UPDATE, or - SKG MEASUREMENT REQUEST and SKG MEASUREMENT RESPONSE.

[0084] The proximity base stations gNB 1,..., gNBi, ..., gNBn are adapted to transmit third positioning data Pos3 to the central network 5GC, and more particularly to the module NGC. This transmission of third positioning data Pos3 is done without going through the satellite Sat. For example, the third positioning data Pos3 is transmitted to the central network 5G via an optical fiber. The third positioning data is based on channel measurements carried out by the proximity base stations gNBl,..., gNBi, ..., gNBn on the emissions of the user terminal UE. Preferably, each proximity base station gNBl,..., gNBi, ..., gNBn is adapted to calculate a particular secret key SKG'i which it sends to the central network 5GC.Alternatively, a nearby base station can collect all channel measurements made by the nearby base stations and calculate a global secret key. S KG' corresponding, for example, to a summation or concatenation of the particular secret keys SKG';. This global secret key SKG' is then transmitted to the central network 5GC.

[0085] Following the reception of the second positioning data Pos2 and the third positioning data Pos3, the central network 5GC is adapted to compare these data. It can thus check their compatibility. For example, it can compare the particular secret keys SKGi, SKG'i. Alternatively, the central network 5GC compares the general secret keys SKG, SKG'. If the positioning data Pos2 and Pos3 are compatible, the central network 5GC validates the first positioning data Posl of the user terminal UE and the terminal can continue to use the 5G network.

[0086] [Fig.5] illustrates the steps of a method for validating the positioning of a user terminal.

[0087] In a first step E1, an LMF entity (for “Location Management Function” in English) sends to the user terminal UE a message indicating a number of sources to be measured.

[0088] In a second step E2, the user terminal UE makes a selection of the most powerful sources, i.e. the proximity base stations closest to the user terminal UE.

[0089] In a third step E3, the user terminal UE determines the second positioning data Pos2 from measurements carried out at the PHY layer (L1). This user terminal UE can for this purpose obtain the different particular secret keys SKG from different proximity base stations and transmit them. Alternatively, it can perform an operation on these particular secret keys SKG, such as a summation, to deduce therefrom a general secret key SKG.

[0090] In a fourth step, the user terminal UE transmits the second positioning data Pos2 via an LPP layer (for “LTE Positioning Protocol” in English). In a particular embodiment, the second positioning data Pos2 are transmitted to the central network 5GC with the positioning data Pos1.

[0091] In a fifth step, one of the proximity base stations gNBi sends the third positioning data Pos3. As a reminder, these third positioning data may be channel measurements by the proximity base station gNBi on the transmissions of the user terminal UE or a particular secret key SKG'i produced from these measurements.

[0092] Upon receipt of the second positioning data Pos2 and the third positioning data Pos3, the LMF module can validate the GNSS position of the user terminal UE in a step E6. In the event that there is no validation, the 5G network rejects the user terminal UE in a step E7.

[0093] In an alternative embodiment illustrated in [Fig.l 1], the different steps for a Decision / Reconciliation are presented. In this embodiment, the message may be generated by LCS entities, the AMF, the LMF. The UE SKGi and NG-RAN SKG reconciliation; may be in the LMF or the AMF. The decision may be in the AMF and the LMF. The result may be: - An Invalid Position message (for invalid position); - A UE Rejection message (for rejection of the user terminal); - A UE Restriction message (for a user terminal restriction); - A Valid Position message (for a valid position / validated by the network); - A decision to continue communication and no message.

[0094] In the alternative embodiment illustrated in [Fig.l 1], the 5GC LCS entity can optionally transmit a request for information or a request for a secret key SKG to the AMF, or quite simply the 5GC LCS entity can request the activation of the method based on the notion of a secret key SKG for validation of the positioning of the user terminal. This request can be encapsulated in a field of the message “la. Location Service Request ([Optional] SKG Info Request)”. Following this message, the AMF can carry out step “1b. Location Service Request” and will send to the LMF a message “2. Location Service Request” to specify to the LMF in specific fields that the AMF needs to know the secret keys SKG; for the user terminal (with the proximity base stations) and the secret keys SKG'i for NG-RAN or one or more proximity base stations (with the user terminal) for eg validation of the UE positioning.These requests can be encapsulated in specific fields of the message "2. Location Service Request". Once the exchanges with messages 3al, 3a2, 3a3 are performed between the LMF and NG-RAN Node (e.g. using the NRPPa protocol with the proximity base stations, in step "3a. NG-RAN Node Procedures") and the exchanges with messages 3b 1, 3b2, 3b3 are performed between the LMF and the UE (e.g. using the LPP protocol with the UE, and e.g. using the satellite link, in step "3b. UE Procedures"), the LMF can perform the reconciliation of keys SKG; and SKG'i (Alt 1) and can send in a first alternative (Altl) the message "4. Location Service Response" with a specific field that contains the result(s) for the reconciliation of secret keys SKG; and SKG'i with the UE. In a first alternative (Altl) the message “4.Location Service Response" presents a specific field that contains the result(s) for the reconciliation of SKG secret keys; and SKG'i with the UE. In a second alternative (Alt2) the message "4. Location Service Response" presents a . field or several specific fields with the (complete) results of SKGi and SKG'i secret keys with the UE, and this can be in the form of a report or an update. Following the transmission of the "4. Location Service Response" message, the AMF can perform in a second alternative (Alt2) the reconciliation of SKGi and SKG'i secret keys or simply take one or several decisions (Altl and Alt2) with what to do next (e.g. validate the position of the UE user terminal, reject the UE user terminal from the satellite network, make a restriction of the UE user terminal in the network e.g. in terms of services, invalidate the position of the UE user terminal, or simply continue the communication), including whether to activate the security / encryption between the UE and the satellite link / gNB Satcom with an SKG secret key. Optionally, the AMF can transmit a "5a.Location Services Response » to 5GC LCS entities with information about SKG secret keys or simply the response with activation of the SKG procedure.

[0095] [Fig. 12] illustrates another embodiment showing the different steps for a Decision / Reconciliation with a reconciled SKG activation for communication. [Fig. 12] also illustrates the activation of an encrypted communication between the user terminal UE and the Satcom gNB, using a reconciliation result of SKG secret keys, a global SKG key, a particular secret key, or a general secret key. The SKG secret key can be transmitted by the AMF to the Satcom gNB using an NG-AP protocol.

[0096] Figures 13 to 15 illustrate examples of modifications to the E-CID procedure within the framework of NRPPa TS 38.455.

[0097] [Fig. 13] thus illustrates a first example of modifications to the E-CID procedure within the framework of NRPPa TS 38.455.

[0098] [Fig. 14] illustrates a second example of modifications to the E-CID procedure within the framework of NRPPa TS 38.455.

[0099] [Fig. 15] illustrates a third example of modifications to the E-CID procedure within the framework of NRPPa TS 38.455.

[0100] [Fig. 16] illustrates examples of modification NRPPa TS 38.455;

[0101] [Fig. 17] illustrates a first example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355.

[0102] [Fig. 18] illustrates a second example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355;

[0103] [Fig. 19] illustrates a third example of procedure modification if a measurement on NR E-CID is carried out, according to LPP TS 37.355;

[0104] [Fig.20] illustrates a first example of procedure modification if a measurement on LTE E-CID is carried out, according to LPP TS 37.355;

[0105] [Fig.21] illustrates a second example of procedure modification if a measurement on LTE E-CID is carried out according to LPP TS 37.355.

[0106] The invention thus proposes: - the use of SKG keys to validate geographic positioning for a 5G satellite connection; - SKG information is added to LPP / NRPPa protocols; - this is therefore a second-order SKG use, to validate the transmitted GNSS data / the position obtained by GNSS / the geographic coordinates transmitted by the user terminal; - SKG keys correspond to a digital fingerprint; - the 5GC core network compares the fingerprints and decides whether the user terminal UE will be accepted into the network or not; - once the position authentication is performed, the user terminal and / or the satellite and / or the gateway can use the SKG key to secure the link.

[0107] The invention is not limited to the embodiments described.

[0108] Thus, it is possible to optimize the results depending on who is used as pilot / number of subcarriers and the granulometry / quantization required.

[0109] Thus, the SKG exchange can be periodic or aperiodic.

[0110] Thus, depending on the bandwidth, the SKG size configurations may vary.

[0111] Thus, the invention is applicable in TDD if the uplink and the downlink use the same carrier frequency (reciprocal channel UE->gNBi in UpLink or gNBi ->UE in DownLink for CHi determination, to ensure an estimation of the reciprocal propagation channel at the gNBi level and at the UE level and similar key generations) but also potentially in FDD.

[0112] Thus, the invention may involve the use of a g-SMLC (next-generation Serving Mobile Location Centre) and / or e-SMLC and / or GMLC (Gateway Mobile Location Centre), and / or SLP (SUPL Location Platform, potentially using a Subscriber LCS privacy Profile, for a user-plane based solution) and using a SUPL (Secure User Plane Location), and / or LBS (location-based service) and / or LCS (Location Service), and / or LPP (LTE Positioning Protocol) & NRPPa (NR Positioning Protocol A) protocols, which are specific entities / services / protocols at the core network level. The invention may also use one of these entities / functions: Access and Mobility Management Function (AMF), LMF (Location Management Function), etc.

[0113] In an alternative implementation, the proximity base station may be, for example, a macro cell, a small cell, a pico cell, a wide area BS or any other type of BS (Base Station), or an IAB (Integrated Access Backhaul) node, a Remote Radio Head (RRH), a Transmission Point (TP), an Access Point or a trusted WiFi / WLAN Access Point (AP).

[0114] In another example, instead of using the LPP protocol to transmit the particular secret key SKG; or the general secret key SKG, the UE can use another transmission means, see for example the RRC protocol (for "Radio Resource Control" in English) to transmit the key(s) to the Satcom gNB, and then the Satcom gNB can use a NRPPa type protocol for transmitting the SKG data to the 5GC and / or to LMF / 5G LCS.

[0115] As alternatives for key reconciliation and possible alternatives, the initial SKG usage message can be generated for example by the 5GC, the 5GC LCS entities, the AMF, the LMF, the gNB etc.; the key reconciliation (Pos2, Pos3) can be done for example at the LMF, AMF, etc. level; the decision which concerns the action performed by the 5GC can be for example at the AMF, LMF, etc. level; the result of the decision may be for example a UE rejection message (eg UE Rejection Message to eg UE and / or PCF for the “Policy and Charging Function” function), a UE restriction message (eg UE Restriction Message to eg NG-RAN and / or PCF), an invalid position message (eg Invalid Position Message to eg LMF or 5GC LCS or other 5GC entity(ies)), a valid position message (eg to the LMF or 5GC LCS entities), a decision to continue the communication and without any message transmitted to the different 5GC / NG-RAN / UE entities.

[0116] Other implementation alternatives may use a NAS message (see TS 24.501) which could contain a SKG secret key or the result of the key reconciliation (e.g. a global SKG secret key) between the AMF and the UE or e.g. a REGISTRATION ACCEPT message with SKG information, or possibly a SECURITY MODE COMMAND which informs the UE that the encryption algorithm will be based on SKG (1 bit of information added in the encryption algorithm type). The AMF may also communicate the SKG secret key to the Satcom NG-RAN (or Satcom gNB) in a NG-AP type message (see TS 38.413) with the result of the key reconciliation (e.g. a global SKG secret key) or e.g. a UE CONTEXT MODIFICATION REQUEST message with the "Security Key IE" field equal to e.g. the key / a global SKG secret key. Optionally, the invention may implement securing / encrypting the link between the UE and the 5G NR satellite access network with the secret key SKG.Link encryption / security can be done in one direction or in both directions of communication.

[0117] As an alternative, 5G and especially 5GC implementation can be carried out using Software Defined Network or SDN implementation and / or concepts.

[0118] Thus, to measure the CHi channels, the invention can use the following pilots (non-restrictive examples): Demodulation Reference Signal (DM-RS), Sounding Reference Signals (SRS), Channel State Information Reference Signals (CSI-RS), Positioning Reference Signals (PRS), Tracking Reference Signals (TRS), PSS / SSS (Primary / Secondary Synchronization Signals) and potentially others such as PRACH preambles or other types of signals transmitted by the UE or gNB.

[0119] Thus, it is possible to provide other modifications in other messages among those described in TS 37.355 such as section 6.5.9 for NR E-CID, but also NR DL-TDOA, NR DL-AoD or NR Multi-RTT.

[0120] The user terminal UE and the proximity base stations can determine the positioning data (Pos2, respectively Pos3) from measurements carried out at the PHY layer (L1), after the FFT / DFT processing (FFT if direct fast Fourier transform or “Fast Fourier Transform” in English, DFT if discrete Fourier transform or “Discrete Fourier Transform” in English) in reception, and preferably before the equalization of the radio channel.

Claims

1. Claims Method for validating a positioning of a 5G compatible user terminal (UE) in a 5G cell network, said user terminal (UE) being adapted to exchange service frames (Ts) with a satellite (Sat), said satellite (Sat) being adapted to exchange link feeder frames (TLF) with a gateway (GW), said gateway (GW) being connected to a 5G core network (5GC), each 5G cell of the 5G cell network comprising at least one base station, each base station being able to communicate with the 5G core network (5GC), said user terminal (UE) being able to communicate at a given time with several base stations of the 5G cells, called proximity base stations (gNBl,..., gNBi, ..., gNBn), said validation method comprising: - a step of determining first positioning data (Posl) of the user terminal (UE), said first positioning data (Posl) being a GNSS position of the user terminal (UE), said first positioning data (Posl) being sent by the user terminal (UE) to the 5G central network via the satellite (Sat);. - a step of sending by the user terminal (UE) second positioning data (Pos2) of the user terminal (UE) to the 5G core network, said second positioning data (Pos2) being based on all or part of the channel measurements carried out by the user terminal (UE) on the proximity base stations (gNBl,..., gNBi,..., gNBn), said sending step being carried out via the satellite (Sat); - a step of sending by the proximity base stations (gNBl,..., gNBi,..., gNBn) third positioning data (Pos3) of the user terminal (UE) to the 5G core network, said third positioning data being based on channel measurements carried out by the proximity base stations (gNB 1,..., gNBi,..., gNBn) on the emissions of the user terminal (UE), said sending step being carried out without going through the satellite (Sat); - a step of comparing, in the 5G central network, the second positioning data (Pos2) with the third positioning data (Pos3), the first positioning data (Posl) of the user terminal (UE) being validated if the second positioning data (Pos2) are compatible with the third positioning data (Pos3).

2. Validation method according to claim 1, in which the second positioning data are measurements by the user terminal (UE) of the propagation channels carried out on the transmissions of the proximity base stations (gNBl,..., gNBi, ..gNBn).

3. Validation method according to claim 1, in which the second positioning data are particular secret keys (SKG;) generated by the user terminal (UE), said particular secret keys (SKGi) being calculated from measurements of the propagation channels carried out by the user terminal (UE) on the transmissions of the proximity base stations (gNBl,..., gNBi,...,gNBn).

4. Validation method according to claim 3, wherein the second positioning data is a global secret key SKG calculated from the particular secret keys (SKG;).

5. Validation method according to any one of claims 1 to 4, in which the third positioning data are the measurements of the propagation channels carried out by the proximity base stations (gNBl,..., gNBi,..., gNBn) on the emissions of the user terminal (UE).

6. Validation method according to any one of claims 1 to 4, in which the third positioning data are particular secret keys SKG'i generated by the proximity base stations (gNBl,..., gNBi,..., gNBn), said secret keys being calculated from measurements of the propagation channels carried out by said proximity stations (gNBl,..., gNBi,..., gNBn) on the emissions of the user terminal (UE).

7. Validation method according to claim 6, wherein the third positioning data is a global secret key SKG' of base station calculated from the particular secret keys (SKG'i).

8. Validation method according to claims 6 or 7, wherein the secret keys (SKG;, SKG'i) are added on LPP / NRPPa protocols in their transmission to the 5G core network.

9. A validation method according to any one of claims 1 to 8, wherein said method initially comprises a step user terminal (UE) authentication in the 5G core network.

10. A 5G communication system comprising: - a 5G cellular radio network, each cell of said 5G network comprising at least one base station, each base station being adapted to communicate with a 5G compatible user terminal (UE); - a satellite (Sat), said satellite (Sat) being adapted to exchange service frames (Ts) with the user terminal (UE); - a gateway (GW), said gateway (GW) being adapted to exchange link feeder frames (TLF) with the satellite (Sat); - a 5G core network (5GC), said core network (5GC) being connected to the gateway (GW), said core network (5GC) being capable of communicating with the base stations; - said user terminal (UE) being able to communicate at a given time with several base stations, called proximity base stations (gNB 1,..., gNBi,..., gNBn); said 5G communication system (1) being capable of implementing the steps of a method for validating a positioning of the user terminal (UE) in the 5G cell network, according to any one of claims 1 to 9.

11. Method for exchanging first positioning data (Posl) and second positioning data (Pos2) intended to be implemented by a 5G compatible user terminal (UE) for validation of a positioning of said user terminal (UE) in a 5G cellular radio network, said validation being carried out according to a validation method according to any one of claims 1 to 9, said user terminal (UE) being adapted to exchange service frames (Ts) with a satellite (Sat), said satellite (Sat) being adapted to exchange link feeder frames (TLF) with a gateway (GW), said gateway (GW) being connected to a 5G core network (5GC), each 5G cell of the 5G cellular radio network comprising at least one base station, each base station being able to communicate with the 5G core network (5GC), said user terminal (UE) being able to communicate at a given time with several base stations,so-called base stations of,

12.

13. proximity (gNB 1,..., gNBi, ..., gNBn), said data exchange method comprising: - a step of determining the first positioning data (Posl) of the user terminal (UE), said first positioning data (Posl) being a GNSS position of the user terminal (UE), said first positioning data (Posl) being sent by the user terminal (UE) to the 5G central network via the satellite (Sat); - a step of sending by the user terminal (UE) the second positioning data (Pos2) of the user terminal (UE) to the 5G core network, said second positioning data (Pos2) being based on all or part of channel measurements carried out by the user terminal (UE) on the proximity base stations (gNB 1,..., gNBi, ..., gNBn), said sending step being carried out via the satellite (Sat), said second positioning data (Pos2) being able to be compared with third positioning data (Pos3), said third positioning data (Pos3) being adapted to be sent by the proximity base stations (gNB 1,..., gNBi, ..., gNBn) without going through the satellite (Sat), said third positioning data (Pos3) being based on channel measurements carried out by the proximity base stations (gNB 1,..., gNBi, ..., gNBn) on the emissions of the user terminal (UE), the first positioning data (Posl) of the user terminal (UE) being validated if the second positioning data (Pos2) are compatible with the third positioning data (Pos3). 5G compatible user terminal, said user terminal (UE) being able to implement the steps of a method for exchanging first positioning data (Posl) and second positioning data (Pos2) of claim 11 for validating a positioning of said user terminal (UE) in a 5G cellular radio network. Computer program comprising instructions usable by a 5G compatible user terminal (UE) according to claim 12, which when executed or interpreted by said user terminal (UE) trigger the implementation of a method for exchanging first positioning data (Posl) and second positioning data (Pos2) according to claim

14. 11 for validation of a positioning of said user terminal (UE) in a 5G cell network. Method for exchanging third positioning data (Pos3) intended to be implemented by a base station for validating the positioning of a 5G-compatible user terminal (UE) in a 5G cellular radio network, said validation being carried out according to a validation method according to any one of claims 1 to 9, said base station, called proximity base station, being able to communicate at a given time with said user terminal (UE), said user terminal (UE) being adapted to exchange service frames (Ts) with a satellite (Sat), said satellite (Sat) being adapted to exchange link feeder frames (TLF) with a gateway (GW), said gateway (GW) being connected to a 5G core network (5GC), the base station being able to communicate with said 5G core network (5GC), said data exchange method comprising: - a step of sending third partial positioning data (Pos31, ..., Pos3i, ..., Pos3n) to the 5G core network (5GC) without going through the satellite (Sat), said third positioning data being based on channel measurements carried out by the proximity base station on the emissions of the user terminal (UE), said third partial positioning data (Pos31, ..., Pos3i, ..., Pos3n) being adapted to be combined with third partial positioning data (Pos31, ..., Pos3i, ..., Pos3n) based on channel measurements carried out by the proximity base stations (gNB 1, ..., gNBi, ..., gNBn) on the emissions of the user terminal (UE) at the given time to form third positioning data (Pos3), said third positioning data (Pos3) being adapted to be compared with second positioning data (Pos2), said second positioning data having been sent by the user terminal (UE) to the 5G core network via the satellite (Sat), said second positioning data (Pos2) being based on the channel measurements carried out by the user terminal (UE) on the proximity base stations (gNB 1,..., gNBi, ..., gNBn), the first positioning data (Posl) of the user terminal (UE) in the cellular radio network being validated if. the second positioning data (Pos2) are compatible with the third positioning data (Pos3), said first positioning data (Posl) being a GNSS position of the user terminal (UE), said first positioning data (Posl) being sent by the user terminal (UE) to the 5G core network via the satellite (Sat).

15. Base station capable of implementing the steps of a method for exchanging third positioning data (Pos3) according to claim 14 for validating a positioning of a user terminal (UE) in a 5G cellular radio network.

16. Computer program comprising instructions usable by a base station (gNB 1,..., gNBi,..., gNBn) according to claim 15, which when executed or interpreted by said base station (gNB 1,..., gNBi,..., gNBn) trigger the implementation of a method for exchanging third positioning data (Pos3) according to claim 14 for validating a positioning of a user terminal (UE) in a 5G cellular radio network.

17. Method for processing first positioning data (Posl), second positioning data (Pos2) and third positioning data (Pos3) of a 5G-compatible user terminal (UE) in a 5G cellular radio network, said user terminal (UE) being adapted to exchange service frames (Ts) with a satellite (Sat), said satellite (Sat) being adapted to exchange link feeder frames (TLF) with a gateway (GW), said gateway (GW) being connected to a 5G core network (5GC), each 5G cell of the 5G cellular radio network comprising a base station, each base station being able to communicate with the 5G core network (5GC), said user terminal (UE) being able to communicate at a given time with several base stations of the 5G cells, called proximity base stations (gNBi,..., gNBi,..., gNBn), said processing method comprising: - a step of receiving the first positioning data (Posl) of the user terminal (UE), said first positioning data (Posl) being a GNSS position of the user terminal (UE), said first positioning data (Posl) being sent by the user terminal (UE) via the satellite (Sat);. - a step of receiving second positioning data (Pos2) from the user terminal (UE), said second positioning data (Pos2) being based on all or part of channel measurements carried out by the user terminal (UE) on the proximity base stations (gNBl,..., gNBi, gNBn), said second positioning data (Pos2) being sent by the user terminal (UE) via the satellite (Sat); - a step of receiving third positioning data (Pos3), said third positioning data being based on channel measurements carried out by the proximity base stations (gNBl,..., gNBi,..., gNBn) on the transmissions of the user terminal (UE), said sending step being carried out by the proximity base stations (gNBl,..., gNBi,..., gNBn) without going through the satellite (Sat); - a step of comparing the second positioning data (Pos2) with the third positioning data (Pos3), the first positioning data (Posl) of the user terminal (UE) being validated if the second positioning data (Pos2) are compatible with the third positioning data (Pos3).

18. Access network (RAN) and 5G core network (5GC) capable of implementing the steps of a method for processing positioning data (Posl, Pos2, Pos3) according to claim 17 for validating a positioning of a user terminal (UE) in a 5G cellular radio network.

19. Computer program comprising program instructions operable by an access network (RAN) and a 5G core network (5GC) according to claim 18, which when executed or interpreted by said access network (RAN) and 5G core network (5GC) trigger the implementation of a method for processing positioning data (Posl, Pos2, Pos3) according to claim 17 for validating a positioning of a user terminal (UE) in a 5G cellular radio network.

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