Embodiments of the present invention refer to a wireless communication system, to a cell network controller for a wireless communication system and to a user equipment. Further embodiments refer to a method for localization management and the respective computer program. Preferred embodiments refer to an approach for localization management / tracking area management for non-terrestrial networks. In general, embodiments of the present invention are applied in connection with non-terrestrial networks, like satellite networks or other non-terrestrial networks, e.g. being based on high-altitude platforms.

Location management (LM) is a function of mobile cellular networks, which allows the network to locate the user. Especially when the UE is not active, this function ensures the knowledge of the rough position of the UE to establish the connection for an incoming call to the UE (paging), if needed.

Before discussing localization management, especially localization management approaches in the context of GSM or UMTS, the principal structure of a terrestrial network and a non-terrestrial network will be discussed.

Fig. 8 below is a schematic representation of an example of a terrestrial wireless network 100 including a core network 102 and a radio access network 104.

The radio access network 104 may include a plurality of base stations gNBi to gNB5l each serving a specific area surrounding the base station schematically represented by respective cells 108i to 106s. The base stations are provided to serve users within a cell. The term base station, BS, refers to as gNB in 5G networks, eNB in UMTS/LTE/LTE-A/ LTE-A Pro, or just BS in other mobile communication standards. A user may be a stationary device or a mobile device. Further, the wireless communication system may be accessed by mobile or stationary loT devices which connect to a base station or to a user. The mobile devices or the loT devices may include physical devices, ground based vehicles, such as robots or cars, aerial vehicles, such as manned or unmanned aerial vehicles (UAVs), the latter also referred to as drones, buildings and other items or devices having embedded therein electronics, software, sensors, actuators, or the like as well as network connectivity that enable these devices to collect and exchange data across an existing network infrastructure. Fig. 8a shows an exemplary view of only five cells, however, the wireless communication system may include more such cells. Fig. 8a shows two users UEi and UE2, also referred to as user equipment, UE, that are in cell IO62 and that are served by base station gNB2. Another user UE3 is shown in cell 1064 which is served by base station gNB4. The arrows IO81, IO82 and IO83 schematically represent uplink/downlink connections for transmitting data from a user UE1, UE2 and UE3 to the base stations gNB2, gNB4 or for transmitting data from the base stations gNB2, gNB4 to the users UE1, UE2, UE3. Further, Fig. 8a shows two loT devices 110i and 1102 in cell 1064, which may be stationary or mobile devices. The loT device 110i accesses the wireless communication system via the base station gNB4 to receive and transmit data as schematically represented by arrow 112i. The loT device 1102 accesses the wireless communication system via the user UE3 as is schematically represented by arrow 1122. The respective base station gNBi to gNBs may be connected to the core network 102, e.g. via the S1 interface, via respective backhaul links 114i to 1145, which are schematically represented in Fig. 8a by the arrows pointing to“core”. The core network 102 may be connected to one or more external networks. Further, some or all of the respective base station gNBi to gNBs may connected, e.g. via the S1 or X2 interface or Xn interface in NR, with each other via respective backhaul links 1161 to 1165, which are schematically represented in Fig. 8 by the arrows pointing to "gNBs”. The wireless network or communication system depicted in Fig. 8a may by a heterogeneous network having two distinct overlaid networks, a network of macro cells with each macro cell including a macro base station, like base station gNBi to gNBs, and a network of small cell base stations (not shown in Fig. 8a), like femto or pico base stations.

For data transmission a physical resource grid may be used. The physical resource grid may comprise a set of resource elements to which various physical channels and physical signals are mapped. For example, the physical channels may include the physical downlink and uplink shared channels (PDSCH, PUSCH) carrying user specific data, also referred to as downlink and uplink payload data, the physical broadcast channel (PBCH) carrying for example a master information block (MIB) and a system information block (SIB), the physical downlink and uplink control channels (PDCCH, PUCCH) carrying for example the downlink control information (DCI), etc. For the uplink, the physical channels may further include the physical random access channel (PRACH or RACH) used by UEs for accessing the network once a UE synchronized and obtained the MIB and SIB. The

physical signals may comprise reference signals (RS), synchronization signals and the like. The resource grid may comprise a frame or radio frame having a certain duration, like 10 milliseconds, in the time domain and having a given bandwidth in the frequency domain. The frame may have a certain number of subframes of a predefined length, e.g., 2 subframes with a length of 1 millisecond. Each subframe may include two slots of 6 or 7 OFDM symbols depending on the cyclic prefix (CP) length. A frame may also consist of a smaller number of OFDM symbols, e.g. when utilizing shortened transmission time intervals (sTTI) or a mini-slot/non-slot-based frame structure comprising just a few OFDM symbols.

The wireless communication system may be any single-tone or multicarrier system using frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, e.g. DFT-s-OFDM. Other waveforms, like non-orthogonal waveforms for multiple access, e.g. filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) or universal filtered multi carrier (UFMC), may be used. The wireless communication system may operate, e.g., in accordance with the 4G LTE, 4.5G LTE-Advanced pro or the 5G NR, New Radio, standard.

In the wireless communication network as shown in Fig. 8a the radio access network 104 may be a heterogeneous network including a network of primary cells, each including a primary base station, also referred to as a macro base station. Further, a plurality of secondary base stations, also referred to as small cell base stations, may be provided for each of the macro cells.

In addition to the above described terrestrial wireless network also non-terrestrial wireless communication networks exist. Fig. 8b below is a schematic representation of an example of a non-terrestrial wireless communication network 150 including a core network 152 and a radio access network 154. Other than the terrestrial wireless network of Fig. 8b, the nonterrestrial wireless network 150 includes a plurality of transceivers 156, like satellites, and/or airborne transceivers 158, like unmanned aircraft systems. The respective or airborne transceivers 156, 158 may be implemented in respective space borne or airborne vehicles, like the above mentioned satellites or unmanned aircraft systems. The transceivers 156 and 158 are provided to serve one or more users, like the UE or the loT device 1 10 shown in Fig. 8b, which are provided on or above ground 160. The UE and the IoT device may be devices as described above with reference to Fig. 8a. The arrows 158i to 1584 schematically represent uplink/downlink connections for communicating data between the user UE, 110 and the respective transceiver 156, 158. The transceivers 156, 158 are connected to the core network 152 as is schematically represented by the arrows 162i, 1622. The above described non-terrestrial wireless communication network or system may operate in a similar way as the terrestrial system described above with reference to Fig. 8a, for example in accordance with the 4G LTE, 4.5G LTE-advanced pro or the 5G NR, new radio, standard.

Data communicated between the users UE, 1 10 and the transceivers 106, 156, 158 of the above described communication networks may be overlaid with noise while being transmitted over the channel 108, 1 12, 158 so that the data may not be processed correctly or may not be processed at all at the receiver. For example, when the data to be transmitted is encoded using a predefined code, the encoded data is generated at the transmitter and forwarded to the receiver over the channel. During the transmission, the encoded data may be overlaid with noise to such an extent that decoding of the encoded data is not possible, e.g., because of noisy channel situations. To address such a situation, a retransmission mechanism may be employed. For example, when the receiver detects that the encoded data cannot be decoded, a retransmission from the transmitter or sender is requested. For example, a hybrid automatic repeat request, HARQ, may be used to request a retransmission from the transmitter, like the UE, to correct decoding failures. At the transmitter, encoding the data includes generating redundancy that may include redundant bits that are added to the data to be transmitted. During a first transmission only a part of the redundancy may be transmitted. When a retransmission is requested, further parts of the redundancy, also referred to as additional or incremental redundancy, may be send to the receiver. For example, HARQ may employ chase combining (every re-transmission contains the same information - data and parity bits), or incremental redundancy (every re-transmission contains different parity bits than the previous one). The retransmission, however, causes a delay due to the additional round-trip time (RTT) which includes the propagation delays over the network and the processing delays at the UE and the receiver.

It is noted that the information in the above section is only for enhancing the understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

The demand for (worldwide) connectivity is dramatically increasing due to a rising number of different services and data demands in a more and more connected world. This also includes connectivity anytime and everywhere. Even if the number of connected areas around the world dramatically increases, it will not be possible to serve every spot on the entire earth (underserved areas, maritime, planes, etc.) by stationary/terrestrial cellular networks.

In order to support these needs, cellular networks need to be supported by non-stationary networks as well. These networks could consist of e.g. drones, airplanes, high altitude platforms, low earth orbit satellites, medium earth orbit satellites. By adding non-stationary base stations to the networks of the future the coverage and also the reliability could be easily and dramatically enhanced, which would be necessary for many future services and applications.

(Connectivity between all these different types of platforms will be necessary to support the quality of service (QoS) needs and to ensure service sustainability, e.g. in disaster relief situations)

Claims

1. A wireless communication system (150) comprising;

at least a first terrestrial or non-terrestrial base station (10, 10’, 156), the first base station (10, 10', 156) configured to generate one or more beams (1 Obi, 10bi’, 10b2’) for covering at least a first beam coverage area;

wherein the first base station (10, 10’, 156) is configured to broadcast at least to the first beam coverage area (12) a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b).

2. A wireless communication system (150) according to one of the previous claims, wherein the first base station (10, 10’, 156) is configured to broadcast at least to the first beam coverage area (12) a first tracking area ID belonging to a first tracking region (12a) or a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b) just during a limited predetermined first time period.

3. A wireless communication system (150) comprising:

at least a first terrestrial and/or non-terrestrial base station (10, 10’, 156), the first base station (10, 10’, 156) configured to generate one or more beams (10bl, 10bi’, 10b2’) for covering at least a first beam coverage area (12);

wherein the first base station (10, 10’, 156) is configured to broadcast at least to the first beam coverage area (12) first tracking area ID belonging to a first tracking region (12a) or a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b) just during a limited predetermined first time period.

4. A wireless communication system (150) according to claim 2 or 3, wherein the first base station (10, 10’, 156) is configured to broadcast at least to a second beam

coverage area (12) another tracking area ID belonging to another tracking region during a limited predetermined second time period subsequent to the first time period and/or to adapt the list of tracking area IDs for the limited predetermined second time period subsequent to the first time period.

5. A wireless communication system (150) according to claim 4, wherein the communication system (150) comprises a core network controller configured to control the first base station (10, 10’, 156) with regard to the broadcasted tracking area ID and/or with regard to adapting the list of tracking area IDs.

6. A wireless communication system (150) according to claim 4 or 5, wherein the instruction to adapt the list of tracking area IDs ahead of time is performed by defining validity time window information for each list entry of list of tracking area IDs.

7. A wireless communication system (150) according to claim 4, 5 or 6, wherein the list of tracking area IDs of the second time period comprises the second tracking area ID belonging to the second tracking region (12b) and a third tracking area ID belonging to a third tracking region (12c); and /or

wherein the list of tracking area IDs of the second time period comprises the second tracking area ID belonging to the second tracking region (12b), but not the first tracking area ID belonging to a first tracking region (12a); and/or

wherein the list of tracking area IDs of the second time period comprises the third tracking area ID belonging to a third tracking region and a fourth tracking area ID belonging to a fourth tracking region.

8. A wireless communication system (150) according to one of the previous claims, further comprising a user equipment being configured to receive the coverage beam and to determine its tracking region by comparing a tracking area ID assigned with the first and second tracking area IDs of the received list.

9. A wireless communication system (150) according to claim 8, wherein the equipment is configured

to report a single tracking area ID to the core network controller, e.g. the first entry; and/or

to report UE reports multiple tracking area IDs to the core network controller with or without the beam/satellite ID;

to report intersecting tracking area IDs from multiple beams/satellites back to the core network controller;

to report multiple tracking area IDs in combination with time information.

10. A wireless communication system (150) according to one of the previous claims, wherein first base station (10, 10’, 156) is a moving or Earth fixed beam footprint LEO satellite or an Earth fixed beam footprint GEO satellite, and/or

wherein first base station (10, 10’, 156) comprises single or multispot beam satellite or transparent or regenerative satellite; or

wherein first base station (10, 10’, 156) is a moving base station (10, 10’, 156) e.g. a Drone or High-Altitude Platform (HAPS); or

wherein the wireless communication system (150) is formed by a terrestrial network and/or wherein the wireless communication system supports heterogeneous networks.

11. A wireless communication system (150) according to one of the previous claims, wherein the communication system (150) comprises a second base station (10, 10’, 156) which is configured to broadcast at least to the first beam coverage area (12), the first tracking area ID belonging to a first tracking region (12a) or a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b) during a limited predetermined further time period.

12. A wireless communication system (150) according to one of the previous claims, wherein the first beam coverage area (12) comprises at least during the first time period at least two tracking regions, each assigned to a fixed tracking area ID.

13. A wireless communication system (150) according to one of the previous claims, wherein a wireless communication system (150) routes a paging message to the

one or more beams (1 Obi, 10bi’, 10b2’) that currently broadcast the first tracking area ID if the paging message is dedicated to a user equipment within the first tracking region (12a), and/or routes paging messages to the one or more beams (1 Obi, 10b!’, 10b2’) that currently broadcast the second tracking area ID if the paging message is dedicated to a user equipment within the second tracking region (12b).

14. Core network controller for the wireless communication system (150) according to one of the previous claims, which is configured to control the first base station (10, 10’, 156) with regard to the broadcasted tracking area ID, with regard to the list of broadcasted tracking area IDs, with regard to adapting the broadcasted tracking area ID and/or with regard to adapting the list of tracking area IDs.

15. Core network controller for the wireless communication system (150) configured to route paging messages to the one or more base stations (10, 10’, 156) selected for currently broadcasting using one or more beams (1 Obi, 10bi’, 10b2’) the first tracking area ID if the paging message is dedicated to a user equipment within the first tracking region (12a) and/or to the one or more base stations (10, 10’, 156) selected for currently broadcasting using one or more beams (1 Obi, 10bl·, 10b2’) the second tracking area ID if the paging message is dedicated to a user equipment within the second tracking region (12b).

16. A user equipment for the wireless communication system (150) according to one of the claims 1 - 13, which is configured to receive the coverage beam and the list broadcasted using the coverage beam and to determine its tracking region by comparing a tracking area ID assigned to the user equipment with the tracking area IDs comprised by the list.

17. A user equipment according to claim 16, wherein the user equipment receiving another coverage beam from another base station (10, 10', 156) during another subsequent time period, wherein the user equipment is configured to determine its tracking region independently due to which base station (10, 10’, 156) the assigned tracking area ID or the list comprising the assigned tracking area ID has been received.

18. A method for location management, the method comprises:

broadcasting at least to the first beam coverage area (12) - using a first terrestrial or non-terrestrial base station, the first base station (10, 10’, 156) generating one or more beams (1 Obi, 10b!’, 10b2’) for covering a first beam coverage area - a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b).

19. A method for location management, the method comprises:

broadcasting at least to the first beam coverage area - using a first terrestrial or non-terrestrial base station (10, 10’, 156), the first base station (10, 10’, 156) generating one or more beams (1 Obi, 10b!’, 10b2’) for covering a first beam coverage area (12) - the first tracking area ID belonging to a first tracking region (12a) or a list of tracking area IDs comprising a first tracking area ID belonging to a first tracking region (12a) and a second tracking area ID belonging to a second tracking region (12b) just during a limited predetermined first time period; and/or

broadcasting at least to the second beam coverage area (12) - using a second terrestrial or non-terrestrial base station, the second base station (10, 10’, 156) generating one or more beams (1 Obi, 10bi’, 10b2’) for covering a second beam coverage area (12) - the first tracking area ID belonging to a first tracking region (12a) or another list of tracking area IDs comprising the first tracking area ID belonging to the first tracking region (12a) just during a limited predetermined second time period subsequent to the first time period.

20. A method for location management according to claim 19, further comprising controlling the first base station (12a) with regard to the broadcasted tracking area ID and/or with regard to adapting the list of tracking area IDs.

21. A method for location management according to claim 20, wherein the controlling is performed by defining the list of tracking area IDs for the first time period and another list of tracking area IDs for the second time period or by adapting the list of tracking area IDs ahead of time / for the second time period or by defining validity time window information for each list entry of list of tracking area IDs.

22. Computer-readable digital storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method according to one of claims 18-21.

23. The wireless communication system of any one of the claims 1- 17,

wherein the user equipment comprises one or more of

- a mobile terminal, or

- stationary terminal, or

- cellular IoT-UE, or

- vehicular UE, or

- an loT or narrowband loT, NB-loT, device, or

a ground based vehicle, or

- an aerial vehicle, or

- a drone, or

- a moving base station, or

road side unit, or

- a building, or

- any other item or device provided with network connectivity enabling the item/device to communicate using the wireless communication network, e.g., a sensor or actuator, and/or

wherein the terrestrial or non-terrestrial base station comprises one or more of

a macro cell base station, or

a small cell base station, or

a central unit of a base station, or

a distributed unit of a base station, or

a road side unit, or

a UE, or

a remote radio head, or

an AMF, or

an SMF, or

a core network entity, or

a network slice as in the NR or 5G core context, or

a spaceborne vehicle, like a satellite or a space vehicles at a specific altitude and orbital period or plane, e.g., a low earth orbit (LEO), a medium earth orbit (MEO), a geosynchronous orbit (GSO), a geostationary orbit (GEO), or a high earth orbit (HEO), or

an airborne vehicle, like an unmanned aircraft system (UAS), e.g., a tethered UAS, a lighter than air UAS (LTA), a heavier than air UAS (HTA) and a high altitude UAS platforms (HAPs), or

any transmission/reception point, TRP, enabling an item or a device to communicate using the wireless communication network, the item or device being provided with network connectivity to communicate using the wireless communication network.

24. The wireless communication system of any one of the claims 1-13, comprising a core network or a core network entity and a RAN network, like an AMF, the core network or the core network entity configured to page a UE in the wireless communication system only via those transmission points indicated in the UE’s list; and/or

wherein the wireless communication system includes

- a terrestrial network, or

- a non-terrestrial network, or

- networks or segments of networks using as a terminal an airborne vehicle or a spaceborne vehicle, or

- a combination thereof.