WO2025194433A1

WO2025194433A1 - Registration method, store and forward (s＆f) paging method, and related devices

Info

Publication number: WO2025194433A1
Application number: PCT/CN2024/082973
Authority: WO
Inventors: Peng Tan; Cong SHI
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2024-03-21
Filing date: 2024-03-21
Publication date: 2025-09-25
Anticipated expiration: 2026-09-21

Abstract

A Store and Forward (S&F) paging method, including storing a paging message by a satellite; and forwarding the paging message to a terminal device once the satellite re-establishes visibility or connectivity with the terminal device. This ensures that the terminal device eventually receives the intended paging message.

Description

REGISTRATION METHOD, STORE AND FORWARD (S＆F) PAGING METHOD, AND RELATED DEVICES

TECHNICAL FIELD

The present application relates to wireless communication, and more particularly, to a registration method, a Store and Forward (S&F) paging method, and related devices.

BACKGROUND ART

Paging is a mechanism used by the mobile network to notify a user equipment (UE) about incoming calls, SMS, or data services when the UE is in idle mode. When initiating a paging procedure, the network needs to know the last known area (e.g., Tracking Area in LTE or Registration Area in 5G) where the UE signaled its presence.

In 4G (LTE) , the MME (Mobility Management Entity) checks the last known Tracking Area (TA) of the UE. MME then sends a paging message to all eNBs serving the cells within that TA. The eNBs broadcast the paging message on the PCCH (Paging Control Channel) .

In 5G, the AMF (Access and Mobility Management Function) checks the last known Registration Area of the UE. The AMF then sends a paging message to all gNBs (or NG-RAN nodes) in that area. The gNBs broadcast the paging message on an appropriate channel.

If the UE receives the paging message and recognizes its own identity (usually sent as a temporary identity like TMSI (Temporary Mobile Station Identifier) in LTE) , it initiates a service request procedure to move from idle to connected mode. This involves sending a service request to the network indicating its readiness to receive the incoming call or data.

If the UE doesn't respond to the initial paging message (maybe because it was out of coverage or turned off) , the network might retry the paging message a few more times before giving up.

Integration of satellite components into EPS (Evolved Packet System) and 5GS (5G System) has been studied in 3GPP Rel 16, Rel 17 and Rel 18, focusing on transparent payloads where satellite-enabled NG-RAN is located on ground. The satellite is equivalent to a RU (Remote Unit) and is fully transparent to the 3GPP protocols.

Most recently, 3GPP SA work group 2 has approved a Rel-19 study item on integration of satellite components in the 5G architecture Phase III. In this phase, the satellite is regenerative where the satellite payload implements an eNB/gNB and necessary core network components.

When the eNB/gNB is on a satellite with a regenerative payload mode, the paging procedures will inherently have unique challenges and considerations due to the nature of satellite communications.

Standard 3GPP core network components typically assume continuous connectivity between its elements. However, satellite connectivity can sometimes be intermittent, particularly when the satellite's visibility doesn't align concurrently with both the UE (User Equipment) and the ground station. Consequently, there may be moments when a satellite OTB (On-Board Transceiver) receives a paging message but cannot promptly relay it to the UE, leaving the message undelivered.

Furthermore, it's worth noting that a satellite's coverage far exceeds that of a terrestrial gNB. This extensive coverage can lead to inefficiencies, as a paging message might be broadcast over an unnecessarily vast area. While strategies such as beamforming or spot beams can pinpoint specific areas, determining the precise beam or spot where the UE resides remains a challenge.

SUMMARY

In a first aspect, some embodiments of the present application provide a registration method, which includes registering a satellite Store and Forward (S&F) operation mode to a network in a registration procedure, wherein a satellite stores a paging message and then forwards the paging message when the satellite operates in the satellite S&F operation mode.

In a second aspect, some embodiments of the present application provide a Store and Forward (S&F) paging method, which includes storing a paging message by a satellite; and forwarding the paging message to a terminal device once the satellite re-establishes visibility or connectivity with the terminal device.

In a third aspect, some embodiments of the present application provide a paging method, which includes using a dedicated Tracking Area Identity (TAI) list for satellite-access in Store and Forward (S&F) mode for paging, wherein the dedicated TAI list contains TAI for a satellite in S&F operation mode coverage areas.

In a fourth aspect, some embodiments of the present application provide a communication device, which includes a processor, configured to call and run program instructions stored in a memory, to execute any of the above-mentioned methods.

DESCRIPTION OF DRAWINGS

In order to more clearly illustrate the embodiments of the present application or related art, the following figures that will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present application, a person having ordinary skill in this field can obtain other figures according to these figures without paying the premise.

FIG. 1 is a block diagram of a terminal device and a network device of wireless communication in a communication controlling system according to an embodiment of the present application.

FIG. 2 is a flowchart of a registration method according to an embodiment of the present application.

FIG. 3 is a flowchart of a Store and Forward (S&F) paging method according to an embodiment of the present application.

FIG. 4 is a schematic diagram illustrating S&F paging call flow according to an embodiment of the present application.

FIG. 5 is a flowchart of a paging method according to an embodiment of the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present application are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

In this document, a combination such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” or “A, B, and/or C” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any combination may contain one or more members of A, B, or C.

The following table includes some abbreviations used in some embodiments of the present application:

This invention discloses how the UE registers the network and the store-and-forward paging approach complemented by a suite of advanced paging strategies. These strategies include predictive scheduling, service prioritization, feedback-enhanced paging, location-based paging retry, and more.

The invention also discloses a dedicated tracking lists-based S&F paging mechanism, optimized for UEs under the coverage of both terrestrial NG-RAN (eNB/gNB) and satellite NG-RAN (eNB/gNB) .

A regenerative satellite payload is equipped with an On-Board Processor (OBP) that can actively process incoming signals rather than merely amplifying and relaying them. This capability enables a store-and-forward (S&F) operation within the satellite, allowing it to retain and subsequently dispatch data during periods of interrupted satellite connectivity, especially when there's non-concurrent visibility between the satellite, the UE, and the ground station. The present application introduces a store-and-forward paging mechanism: Upon receiving a paging message from the core network, the eNB/gNB on the satellite stores it. When connectivity or visibility with the UE is re-established, the satellite then forwards the paging message, ensuring that, despite potential delays, the UE eventually receives the intended message.

To enhance efficiency in determining the precise beam or spot for transmission of the paging message, the present application introduces a dual tracking list mechanism, optimized for UEs under the coverage of both terrestrial NG-RAN (eNB/gNB) and satellite NG-RAN (eNB/gNB) .

FIG. 1 illustrates that, in some embodiments, one or more terminal device (e.g., user equipments (UEs) ) 10 and a network device (e.g., a satellite, a base station (e.g., gNB or eNB) ) 20 for wireless communication in a communication network system 30 according to an embodiment of the present application are provided. The communication network system 30 includes the one or more terminal devices 10 and the network device 20.

The network device (e.g., satellite, base station) 10 can be an entity which is used to transmit or receive information. The network device 20 can be satellite NG-RAN, gNB, eNB, On-Board Processor (OBP) , transmission reception point (TRP) , NodeB in next generation communication or access point in WIFI.

The terminal device (e.g., UE) 10 is an entity which is used to transmit or receive information on the user side, such as a cell phone. The UE can also be called a terminal, UE, mobile station, mobile terminal. The UE can be a mobile phone, pad, VR, AR, wireless terminal of industrial control, wireless terminal of self-driving, wireless terminal of remote medical surgery, wireless terminal of smart grid, wireless terminal of transport safety, wireless terminal of smart city, wireless terminal of smart home, etc.

Furthermore, the terminal device 10 and the network device 20 can be deployed in land, including indoor, outdoor, handheld, on-board. They can also be deployed in other environments, including water, air, plane, drone or satellite.

The one or more terminal devices 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12 and the transceiver 13. The network device 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and the transceiver 23. The processor 11 or 21 may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 is operatively coupled with the processor 11 or 21 and stores a variety of information to operate the processor 11 or 21. The transceiver 13 or 23 is operatively coupled with the processor 11 or 21, and the transceiver 13 or 23 transmits and/or receives a radio signal. The network device 20 and a next generation core network (5GCN) may also communicate with each other either wirelessly or in a wired way. When the communication network system 30 complies with the New Radio (NR) standard of the 3rd Generation Partnership Project (3GPP) , the next generation core network is a backend serving network system and may include an Access and Mobility Management Function (AMF) , User Plane Function (UPF) , and a Session Management Function (SMF) . In one aspect, the terminal device 10 can include almost any consumer electronic device or appliance that can connect to a radio access network and a core network for the releases of 3GPP and further, such as, but not limited to NR networks.

The processor 11 or 21 may include application-specific integrated circuit (ASIC) , other chipset, logic circuit and/or data processing device. The memory 12 or 22 may include read-only memory (ROM) , random access memory (RAM) , flash memory, memory card, storage medium and/or other storage device. The transceiver 13 or 23 may include baseband circuitry to process radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 can be implemented within the processor 11 or 21 or external to the processor 11 or 21 in which case those can be communicatively coupled to the processor 11 or 21 via various means as is known in the art.

FIG. 2 is a flowchart of a registration method according to an embodiment of the present application. Referring to FIG. 2 in conjunction with FIG. 1, the method 200 includes the followings. In Step 210, a satellite Store and Forward (S&F) operation mode is registered to a network in a registration procedure, wherein a satellite stores a paging message and then forwards the paging message when the satellite operates in the satellite S&F operation mode. With this method, satellite S&F paging can be achieved.

In some embodiments, when a terminal device supports the satellite S&F operation mode, a message carries a terminal device operation mode including the satellite S&F operation mode to the network. In some embodiments, the satellite S&F operation mode is determined based on information received from base stations. In some embodiments, multiple access-specific Registration Management (RM) contexts for a terminal device are provided when satellite access in the satellite S&F operation mode and other types of access are registered, and in the multiple access-specific RM contexts, a Globally Unique Temporary Identifier (GUTI) is common to both satellite access in the satellite S&F operation mode and other types of access, a registration state is provided per access type, and a Registration Area is provided per access type. In some embodiments, a dedicated Registration Area is provided for the satellite S&F operation mode. In some embodiments, a dedicated Tracking Area Identity (TAI) list is provided for a terminal device when the terminal device registers over satellite only. In some embodiments, TAI used for the satellite S&F operation mode is dedicated to S&F mode access. In some embodiments, information about the satellite S&F operation mode in Unified Data Management (UDM) .

During registration procedures, e.g. in an Initial Registration, a Mobility Registration Update, a Periodic Registration Update, an Emergency Registration, a Disaster Roaming Initial Registration, or a Disaster Roaming Mobility Registration Update, the UE might notify to the network that it supports one of the following operation modes:

· Store and Forward (S&F) satellite-access only mode. For example, the UE is only covered by satellite operating in S&F mode.

· Integrated/mixed mode where the UE supports Terrestrial NG-RAN, Satellite-enabled NG-RAN and Satellite regenerative NG-RAN in S&F mode. For example, the UE is covered by one or multiple access technologies, including Terrestrial NG-RAN, Satellite-enabled NG-RAN and/or Satellite regenerative NG-RAN in S&F mode, and other Satellite or Terrestrial 3GPP or non-3GPP access technologies.

· Normal mode only or deemed as default mode in certain cases. For example, the UE is covered only by Terrestrial 3GPP or non-3GPP access technologies or Satellite-enabled NG-RAN. This might also include Satellite-enabled Terrestrial technologies, e.g. Satellite-enabled NG-RAN.

Specifically, the above-mentioned UE operation mode could be provided to the network by using registration request message, the indication of UE support for in UE policy Container, or UE MM Core Network Capability. Various messages could carry the UE operation mode to the network.

In the other embodiment, in the absence of the above-mentioned UE operation mode, AMF may also determine RAT Type information, including satellite S&F operation mode based on further information received from the NG-RAN, eNB, or gNB on-board Satellite. In addition to the existing RAT Type for NR satellite access, i.e. NR (LEO) , NR (MEO) , NR (GEO) and NR (OTHERSAT) , satellite access types could include NR (LEO S&F) , NR (MEO S&F) , NR (GEO S&F) and NR (OEHTERSAT S&F) , or in other notation which indicates the satellite access operates in S&F mode.

RM contexts in satellite-access S&F operation mode could be associated with RM contexts in other operation modes. Specifically, when a UE registers with the network over both satellite-access S&F operation mode and other 3GPP or non-3GPP access, the AMF associates multiple access-specific RM contexts for a UE following the method specified in Clause 5.3.2.4 of TS 23.501, i.e., the AMF associates multiple access-specific RM contexts for a UE with:

· a 5G-GUTI that is common to both satellite-access S&F operation mode and other 3GPP or Non-3GPP accesses. This 5G-GUTI is globally unique.

· Registration state per access type (satellite-access S&F operation mode, other 3GPP or Non-3GPP access types)

· a Registration Area per access type: one Registration Area for satellite-access S&F operation mode, another Registration Area for other 3GPP access and another Registration Area for non 3GPP access. These Registration Areas are independent. That is, a dedicated Registration Area is provided for satellite access S&F operation mode.

When a UE registers with the network over satellite-access S&F operation mode or other means using satellite access, the AMF allocates to the UE a registration area that only includes the TAI received from the serving satellite access. A dedicated TAI list is provided for a UE when the UE registers over satellite only.

Furthermore, when the UE operates in S&F mode or the UE is only served by satellite access in S&F mode operation, the UE registers with the network in S&F mode where the AMF allocates a set of tracking areas in TAI List to the UE, considering various information, including mobility pattern and allowed/non-allowed area. The TAI used for S&F mode shall be dedicated to S&F mode access.

AMF or MME stores the S&F mode information in the Unified Data Management (UDM) /Unified Data Repository (UDR) . Alternatively, if the UE is entering into a satellite coverage area, the Tracking Area Updating or Registration Area updating process will automatically update the UE’s profile with S&F mode. The UE mode information is stored in the UDM/UDR.

FIG. 3 is a flowchart of a Store and Forward (S&F) paging method according to an embodiment of the present application. Referring to FIG. 3 in conjunction with FIG. 1, the method 300 includes the followings. In Step 310, a satellite stores a paging message. In Step 320, the satellite forwards the paging message to a terminal device once the satellite re-establishes visibility or connectivity with the terminal device. This ensures that, despite potential delays, the terminal device eventually receives the intended paging message.

In some embodiments, the method further includes returning a S&F paging status message to indicate if the paging message has been successfully received and stored in the satellite. In some embodiments, the method further includes leveraging expected terminal device behavior to determine the time when the satellite forwards the paging message. In some embodiments, the paging message is relayed over Inter Satellite Link (ISL) . In some embodiments, the paging message for S&F paging is priority-based. In some embodiments, the method further includes determining paging strategy based on priority of the paging message. In some embodiments, the method further includes sending a notification back to core network (CN) if the satellite cannot page the terminal device immediately in S&F paging. In some embodiments, if the paging message for S&F paging fails, a terrestrial network is used as a backup for paging the terminal device.

The core network initiates Store and Forward (S&F) paging procedures for the UE. Upon receiving this message from the core network, the NG-RAN, eNB or gNB, or specific components of the OBP on the satellite, stores the paging message. Once the satellite re-establishes visibility or connectivity with the UE, the message is then forwarded to the UE.

The Satellite might return a S&F paging status message to the AMF to indicate if the S&F paging has been successfully received and stored in the Satellite S&F function.

The ideal time for the satellite to forward the paging message can be ascertained from the UE's historical data or movement patterns. Leveraging expected UE behavior, components like the satellite NG-RAN, eNB, gNB, or certain OBP elements can forecast when the UE will be receptive to signals. In a specific embodiment, should a UE discern that it's transitioning into a zone of interrupted satellite visibility, it can, if feasible, transmit a feedback message to the satellite's NG-RAN, eNB, gNB, or select OBP components. This feedback aids these components in refining the paging approach for that specific UE. That is, it is possible to leverage Expected UE Behavior to assist Satellite OBP and/or NG-RAN to determine the time when the S&F satellite operation forwards the S&F paging message.

In another embodiment, if the location of the UE is known, and is covered by the other satellite NG-RAN, eNB, gNB or specific components of the OBP, the paging messages could be delivered to this “the other” or “secondary” satellite through an Inter Satellite Link (ISL) . If the satellite NG-RAN, eNB, gNB or certain components of the OBP has the approximate location information of the UE, it can calculate when the UE will come under visible satellite coverage and retry paging accordingly.

In the other embodiment, if there are multiple paging messages are buffered/stored on the satellite NG-RAN, eNB, gNB or specific components of the OBP due to satellite visibility issues, the NG-RAN, eNB, gNB or certain components of the OBP can prioritize them based on factors like urgency, service type, or QoS requirements. This ensures that when connectivity is resumed, the most critical messages get delivered first.

In the priority-based S&F paging, the paging priority indication could be added in the Paging Message as described in Clause 5.4.3.3 of TS 23.501. That is, priority-based S&F paging is provided for regenerative Satellite payloads.

If the satellite NG-RAN, eNB, gNB or specific components of the OBP recognizes that it cannot page the UE immediately, it can send a notification back to the core network. This allows the network to make informed decisions, like delaying certain non-urgent data transfers or notifying the service provider. That is, notification is sent to core network if it cannot page the UE immediately in S&F paging for regenerative Satellite payloads.

In yet another embodiment, in integrated/mixed terrestrial-satellite networks, if satellite paging fails, the network can attempt to page the UE using the terrestrial network as a backup. That is, terrestrial NG-RAN is used as backup for S&F paging.

The call flow of the S&F paging is illustrated in FIG. 4.

FIG. 5 is a flowchart of a paging method according to an embodiment of the present application. Referring to FIG. 5 in conjunction with FIG. 1, the method 500 includes the followings. In Step 510, a dedicated Tracking Area Identity (TAI) list for satellite-access in Store and Forward (S&F) mode is used for paging, wherein the dedicated TAI list contains TAI for a satellite in S&F operation mode coverage areas. This may minimize unnecessary satellite signaling.

In some embodiments, a Terrestrial TAI list contains tracking area for a terrestrial network. In some embodiments, a criterion is set to determine which of the dedicated TAI list and the Terrestrial TAI list is used for the paging. In some embodiments, a criterion is set to determine which of the dedicated TAI list and the Terrestrial TAI list is used for the paging for a terminal device in hybrid coverage with both terrestrial and satellite. In some embodiments, the criterion includes at least one of the following: the type of service requested; user preference; mobility mode; transition mode; and the Terrestrial TAI list first. In some embodiments, closed-loop feedback is provided for the paging.

Building a dedicated TAI List for satellite-access in S&F mode can be a viable solution for efficient paging in integrated terrestrial-satellite networks. This approach would essentially segment the service areas and allow more targeted paging based on the last known or expected position of the UE.

The Terrestrial TAI list contains tracking area for terrestrial eNB/gNBs, while the dedicated Satellite-access in S&F mode TAI list contains TAI for satellite in S&F operation mode coverage areas.

When the UE reports its location or performs a Tracking Area Update (TAU) , it would indicate whether it is currently under the dedicated S&F TAI list or other types of TAI lists. Depending on the service requirements, mobility pattern, and other factors, the network might determine to switch between these tracking area lists.

A criterion is set to determine which TA lists to use. For example, if the UE’s last known location was a terrestrial network, the core network uses the Terrestrial tracking area list for paging. If the UE was last detected under satellite-only coverage and in S&F mode, the Satellite-access in S&F mode TAI list will be used.

If the UE is in the hybrid coverage with both Terrestrial and Satellite, the AMF could determine which TAI list to use based on the following factors:

· Depending on the type of service requested (e.g. real-time communication) , AMF chooses the appropriate gNB for paging. Real-time services might prioritize terrestrial networks due to lower latency.

· Based on user preference, e.g., always terrestrial, always satellite, or service based, etc.

· If the UE is in high mobility mode, e.g. on airplane, considering using Satellite TAI list.

· If UE is in high transition mode, it transitions between terrestrial and satellite coverage frequently, e.g. while airplane taking off or landing. And if the frequent transitions are detected, multiple TAI list paging might be necessary, or alternatively using these TAI lists in a certain pattern sequentially.

· Start with the terrestrial network if the UE was last seen there. If no response, page via the satellite network. This reduces unnecessary satellite paging while ensuring reachability.

In the other embodiment, if a feedback loop is possible, after each successful paging, the UE provides feedback about the perceived paging efficiency. This feedback aids the network in refining its paging decisions over time. For example, reinforcement learning algorithm could be used to let network gradually learn the most efficient paging strategy based on historical successes and failures. The closed-loop feedback can improve paging decision accuracy.

The disclosure including S&F paging and dedicated TAI list for the S&F paging leads to reduced signaling overhead and faster response times.

Mobility management can be more efficient with clear indication of S&F mode, integrated Satellite and Terrestrial mode or mixed mode as the UE and network have clearer contexts.

Satellite bandwidth is precious. By paging only when the UE is expected to be under satellite coverage, unnecessary satellite signaling can be minimized.

The dedicated S&F TAI list approach also allows to keep some UEs (e.g., high-mobility UEs like vehicles) registered in this dedicated S&F TAI list and other TAI lists or prioritize one over the other based on usage patterns.

The embodiment of the present application further provides a computer readable storage medium for storing a computer program. The computer readable storage medium enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again.

The embodiment of the present application further provides a computer program product including computer program instructions. The computer program product enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again.

The embodiment of the present application further provides a computer program. The computer program enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again.

Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The methods, sequences and/or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

It should be understood that any embodiments disclosed herein as being “non-transitory” do not exclude any physical storage medium, but rather exclude only the interpretation that the medium can be construed as a transitory propagating signal.

The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term ‘comprising’ does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather indicates that the feature is equally applicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to ‘a’ , ‘an’ , ‘first’ , ‘second’ , etc. do not preclude a plurality.

Above all, while the preferred embodiments of the present application have been illustrated and described in detail, various modifications and alterations can be made by persons of ordinary skill in the art. The embodiment of the present application is therefore described in an illustrative but not restrictive sense. It is intended that the present application should not be limited to the particular forms as illustrated, and that all modifications and alterations which maintain the spirit and realm of the present application are within the scope as defined in the appended claims.

Claims

A registration method, comprising:

registering a satellite Store and Forward (S&F) operation mode to a network in a registration procedure, wherein a satellite stores a paging message and then forwards the paging message when the satellite operates in the satellite S&F operation mode.
The method of claim 1, wherein when a terminal device supports the satellite S&F operation mode, a message carries a terminal device operation mode including the satellite S&F operation mode to the network.
The method of claim 1, wherein the satellite S&F operation mode is determined based on information received from base stations.
The method of claim 1, wherein access type of the satellite comprises at least one of NR (LEO S&F) , NR (MEO S&F) , NR (GEO S&F) and NR (OEHTERSAT S&F) , or in other notation which indicates satellite access operates in the S&F operation mode.
The method of claim 1, wherein multiple access-specific Registration Management (RM) contexts for a terminal device are provided when satellite access in the satellite S&F operation mode and other types of access are registered, and wherein in the multiple access-specific RM contexts, a Globally Unique Temporary Identifier (GUTI) is common to both satellite access in the satellite S&F operation mode and other types of access, a registration state is provided per access type, and a Registration Area is provided per access type.
The method of claim 1, wherein a dedicated Registration Area is provided for the satellite S&F operation mode.
The method of claim 1, wherein a dedicated Tracking Area Identity (TAI) list is provided for a terminal device when the terminal device registers over satellite only.
The method of claim 1, wherein TAI used for the satellite S&F operation mode is dedicated to S&F mode access.
The method of claim 1, wherein information about the satellite S&F operation mode in Unified Data Management (UDM) /Unified Data Repository (UDR) .
A Store and Forward (S&F) paging method, comprising:

storing a paging message by a satellite; and

forwarding the paging message to a terminal device once the satellite re-establishes visibility or connectivity with the terminal device.
The method of claim 10, further comprising:

returning a S&F paging status message to indicate if the paging message has been successfully received and stored in the satellite.
The method of claim 10, further comprising:

leveraging expected terminal device behavior to determine the time when the satellite forwards the paging message.
The method of claim 10, wherein the paging message is relayed over Inter Satellite Link (ISL) .
The method of claim 10, wherein the paging message for S&F paging is priority-based.
The method of claim 10, further comprising:

determining paging strategy based on priority of the paging message.
The method of claim 10, further comprising:

sending a notification back to core network (CN) if the satellite cannot page the terminal device immediately in S&F paging.
The method of claim 10, wherein if the paging message for S&F paging fails, a terrestrial network is used as a backup for paging the terminal device.
A paging method, comprising:

using a dedicated Tracking Area Identity (TAI) list for satellite-access in Store and Forward (S&F) mode for paging, wherein the dedicated TAI list contains TAI for a satellite in S&F operation mode coverage areas.
The method of claim 18, wherein a Terrestrial TAI list contains tracking area for a terrestrial network.
The method of claim 19, wherein a criterion is set to determine which of the dedicated TAI list and the Terrestrial TAI list is used for the paging.
The method of claim 19, wherein a criterion is set to determine which of the dedicated TAI list and the Terrestrial TAI list is used for the paging for a terminal device in hybrid coverage with both terrestrial and satellite.
The method of claim 21, wherein the criterion comprises at least one of the following:

the type of service requested;

user preference;

mobility mode;

transition mode; and

the Terrestrial TAI list first.
The method of claim 18, wherein closed-loop feedback is provided for the paging.
A communication device, comprising a processor, configured to call and run program instructions stored in a memory, to execute the method of any of claims 1 to 9.
A communication device, comprising a processor, configured to call and run program instructions stored in a memory, to execute the method of any of claims 10 to 17.
A communication device, comprising a processor, configured to call and run program instructions stored in a memory, to execute the method of any of claims 18 to 23.