Communication method, apparatus and system

Abstract

The embodiments of the present application relate to the technical field of communications. Disclosed are a communication method, apparatus and system, which can support a store and forwarding (S&F) operation by means of a satellite when a service link and a feeder link are not available at the same time, thereby transmitting data from a core network to a terminal device, and enabling the terminal device to reduce power consumption in this scenario. The method comprises: sending a first request by means of a first service link, wherein the first request comprises first information for determining monitoring information; receiving a first response by means of the first service link, wherein the first response comprises a first identifier or first time information, the first identifier corresponds to a first satellite that needs to be monitored, and the first time information corresponds to a first monitoring period; and monitoring at least one satellite on the basis of the first identifier or the first time information, wherein the at least one satellite supports an S&F operation.

Description

Communication method, device and system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 16, 2024, with application number 202410179361.0 and application name “Communication Methods, Devices and Systems”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technologies, and in particular to communication methods, devices, and systems. Background Art

[0003] In a non-terrestrial network (NTN), users (or terminal devices) on the ground communicate with satellites via service links, while satellites can be connected to ground stations on the network side via feeder links, thereby achieving end-to-end connectivity between users, satellites, and networks. Since the satellite is mobile relative to the users on the ground, it provides discontinuous coverage to users on the ground. This situation can also be called discontinuous network coverage for satellite access. Similarly, the satellite is constantly moving relative to the ground station on the network side, so the feeder link between the satellite and the ground station is also discontinuous, which may result in the feeder link and service link in the NTN network not being available at the same time. For example, in some remote areas where there are no ground stations deployed around, when the satellite covers users in this area (the service link is available at this time), it may not be able to connect to an available ground station at the same time (the feeder link is unavailable at this time).

[0004] Since the feeder link and the service link are not available at the same time, users on the ground cannot continuously monitor the satellite and obtain data from the network side in a timely manner. Therefore, monitoring of the satellite by users on the ground may be unnecessary, which is not conducive to meeting the power saving needs of users on the ground. Summary of the Invention

[0005] The embodiments of the present application provide a communication method, apparatus, and system that can transmit data from a core network to a terminal device and reduce the energy consumption requirements of the terminal in a scenario where the feeder link and the service link are not available at the same time.

[0006] The embodiments of this application adopt the following technical solutions:

[0007] In a first aspect, a communication method is provided, comprising: sending a first request via a first service link, the first request including first information for determining monitoring information; receiving a first response via the first service link, the first response including a first identifier or first time information, the first identifier corresponding to a first satellite to be monitored, and the first time information corresponding to a first monitoring period; and monitoring at least one satellite based on the first identifier or the first time information, the at least one satellite supporting a store and forwarding (S&F) operation.

[0008] Based on the communication method provided in the embodiment of the present application, the terminal device can negotiate with the core network to determine the satellites or periods to be monitored, so that the terminal device avoids monitoring all satellites or monitors during the entire period when the service link is available, thereby achieving the effect of saving power consumption. When the feeder link and the service link are not available at the same time, the terminal device can achieve communication with the core network and save power consumption by only monitoring satellites that support S&F operations; because the terminal device does not necessarily have satellite information, it can negotiate with the core network to determine the satellites or monitoring periods to achieve only monitoring of satellites that support S&F operations, and can further screen fewer monitored satellites or shorter monitoring periods to achieve better power saving effects.

[0009] In one possible implementation, the first response includes a first identifier. Accordingly, the first information is used to determine at least one satellite that needs to be monitored, and monitoring at least one satellite according to the first identifier or the first time information is specifically: monitoring the first satellite corresponding to the first identifier according to the first identifier and preset ephemeris information or preset satellite coverage information.

[0010] In this solution, the terminal device determines when to monitor by negotiating the satellites to be monitored. The response message received by the terminal device carries a first identifier. The terminal device can use the first identifier to identify the first satellite and monitor it, thereby avoiding monitoring all satellites and saving energy.

[0011] In a possible implementation manner, the first information includes first auxiliary information, and at least one satellite that needs to be monitored can be determined through the first auxiliary information.

[0012] In this solution, the first information sent by the terminal device includes first auxiliary information. Exemplarily, the first auxiliary information may be monitoring mode information. Based on this first auxiliary information, at least one satellite to be monitored can be determined. The terminal device can use this first auxiliary information to express its satellite selection preference. For example, the terminal device can determine the first auxiliary information based on power conservation requirements, thereby ultimately selecting a satellite to be monitored that better meets the needs of the terminal device.

[0013] In one possible implementation, the first information also includes at least one satellite identification information, including the first identification. In this solution, in addition to the first auxiliary information, the first information sent by the terminal device also includes at least one satellite identification information. This identification information is used to indicate the satellites that the terminal device intends to monitor or does not intend to monitor. By specifically indicating the desired or undesired satellites, the terminal device has a higher probability of monitoring the desired satellite or avoiding monitoring the undesired satellite, better meeting the needs of the terminal device.

[0014] In one possible implementation, the first response includes first time information, which is determined based on second time information included in the first information. The second time information is determined by: determining the second time information based on preset ephemeris information or satellite coverage information, and the second time information indicates that the service link with the satellite is unavailable; and monitoring at least one satellite according to the first identifier or the first time information specifically includes: receiving a paging message from the at least one satellite according to the first time information.

[0015] In this solution, a monitoring period is negotiated to determine when the terminal device monitors the satellite. The terminal device reports the second time information and receives the first time information, and monitors the paging according to the first time information, thus saving power consumption and having simple logic.

[0016] In one possible implementation, the second time information also includes period information corresponding to the period during which the service link with the satellite is unavailable. In this solution, the period information can be used to convey more information about service link unavailability periods, thereby negotiating and determining more monitoring periods, thereby avoiding subsequent signaling overhead.

[0017] In one possible implementation, the first information also includes third time information indicating a desired listening period; the first time information is determined based on the third time information and the second time information. In this solution, by sending the terminal device the desired listening period, the final negotiated listening period is made more consistent with the terminal device's needs.

[0018] In a possible implementation, the method further includes: establishing a second service link with the first satellite; receiving first data from the first satellite; and after receiving the first data, stopping monitoring the first satellite if the second service link is available.

[0019] In this solution, the terminal device stops monitoring in advance, that is, when it is under the coverage of the first satellite, and stops monitoring after determining that the downlink data has been received. The terminal device no longer continues to monitor the first satellite until it is no longer under the coverage of the first satellite, thereby saving power consumption.

[0020] In one possible implementation, the method further includes receiving, from the first satellite, an instruction to stop monitoring, and stopping monitoring of the first satellite in accordance with the instruction. In this solution, by receiving the instruction from the first satellite, the terminal device more reliably determines that downlink data transmission is complete and that monitoring can be stopped, thereby stopping monitoring of the first satellite without compromising communication quality.

[0021] In one possible implementation, the first request is an Attach Request or Tracking Area Update (TAU) Request message; and the first response is an Attach Accept or Tracking Area Update Accept message. This solution uses existing Attach Request or Tracking Area Update Request messages, and Attach Accept or Tracking Area Update Accept messages, thereby saving signaling in the current network and better adapting to the current network architecture.

[0022] In a second aspect, a communication method is provided, the method comprising: receiving a first request from a first terminal device via a feeder link, the first request including first information for determining monitoring information; determining a first response based on the first information, the first response including a first identifier or first time information, the first identifier corresponding to a first satellite to be monitored, the first time information corresponding to a first monitoring period, during which a service link of the first terminal device is available; sending a first response; receiving first data from the first terminal device, and determining to send the first data to the first satellite when the service link between the first terminal device and the first satellite is unavailable, wherein the first satellite supports storage and forwarding (S&F) of the first data.

[0023] Based on the communication method provided in the embodiment of the present application, the mobile management network element determines the monitoring information of the terminal device, such as the monitored satellite or period, by negotiating with the terminal device, so that the terminal device avoids monitoring all satellites or monitors during the entire period when the service link is available, thereby achieving the effect of saving power consumption. By sending the downlink data of the terminal device to the S&F satellite cache when the feeder link is available, the S&F satellite can transmit the downlink data to the terminal device when the service link is available, thereby realizing data communication; at the same time, through negotiation, the terminal device can save power consumption by only monitoring satellites that support S&F operations when the feeder link and the service link are not available at the same time, and also protect the privacy information of the satellite or access network device. In addition, the mobile management network element and the terminal device can further screen fewer monitored satellites or shorter monitoring periods to achieve better power saving effects.

[0024] In one possible implementation, the first response includes a first identifier, and the first information is used to determine monitoring information, including: the first information is used to determine at least one satellite that needs to be monitored; then, the first identifier is determined based on the location of the first terminal device, the preset ephemeris information or satellite coverage information, and the first indication information. In this solution, the mobility management network element and the terminal device determine when the terminal device monitors by negotiating the satellites that need to be monitored. The response message received by the terminal device carries the first identifier. The terminal device can confirm the first satellite and monitor the first satellite through the first identifier, thereby avoiding monitoring all satellites and saving energy.

[0025] In one possible implementation, the first information includes first auxiliary information used to determine the at least one satellite to be monitored. In this solution, the first information received by the mobility management network element includes the first auxiliary information. Exemplarily, the first auxiliary information may be monitoring mode information. Based on this first auxiliary information, the mobility management network element can determine the at least one satellite to be monitored. Using the first auxiliary information, the mobility management network element can obtain the terminal device's preference for satellite selection. For example, the first auxiliary information may be related to the terminal device's power saving requirements, thereby ensuring that the ultimately determined satellite to be monitored better meets the terminal device's needs.

[0026] In one possible implementation, the first information also includes at least one satellite identification information, including the first identification. In this solution, in addition to the first auxiliary information, the first information received by the mobility management network element also includes at least one satellite identification information, which is used to indicate the satellites that the terminal device expects or does not expect to monitor. By specifically indicating the satellites that the terminal device expects to monitor or does not expect to monitor, the mobility management network element negotiates with the terminal device to increase the probability of monitoring the expected satellite or avoiding monitoring the undesired satellite, better meeting the needs of the terminal device.

[0027] In one possible implementation, the first information includes second time information, and the first response includes the first time information. The first time information is determined based on the second time information, the location of the first terminal device, and preset ephemeris information or satellite coverage information. The second time information indicates that the service link of the first terminal device is unavailable. In this solution, a negotiated monitoring period is used to determine when the terminal device monitors the satellite, thereby saving power consumption and providing simple logic.

[0028] In a possible implementation manner, the mobility management network element determines the first satellite according to the second time information, and sends the first data to the first satellite.

[0029] In one possible implementation, the second time information also includes period information corresponding to the period during which the service link with the satellite is unavailable. In this solution, the period information can be used to convey more information about service link unavailability periods, thereby negotiating and determining more monitoring periods, thereby avoiding subsequent signaling overhead.

[0030] In one possible implementation, the first information also includes third time information indicating a desired monitoring period; the first time information is determined based on the third time information and the second time information. In this solution, by including the terminal device's desired monitoring period, the final negotiated monitoring period is more consistent with the terminal device's needs.

[0031] In a possible implementation manner, the mobility management network element periodically maintains the first time information and the second time information according to the first information, thereby avoiding resource waste caused by multiple signaling interactions.

[0032] In one possible implementation, the mobility management network element sends the paging request to the first satellite. The paging request includes the first data and paging time information. The paging time information is used to page the first terminal device, and the paging time information is determined based on the first identifier or the first time information. By including the first data and information indicating the paging time in the paging request, signaling overhead can be reduced, the time required for the satellite to paging the terminal device can be shortened, and system power consumption can be saved.

[0033] According to a third aspect, a communication method is provided, comprising: receiving first data from a core network element via a feeder link, the first data corresponding to a first terminal device; and transmitting the first data to the first terminal device when the feeder link is unavailable and a service link to the first terminal device is available. By supporting store-and-forward operations, a satellite can transmit data to the core network or terminal device even when the feeder link and service link are not available simultaneously.

[0034] In one possible implementation, the method includes: receiving a paging request from a core network element via a feeder link, the paging request including the first data; the paging request also including first paging time information, the first paging time information indicating that the first terminal device is to be paged during a first paging cycle. In this solution, by performing paging based on the paging time information, the monitoring terminal device can be paged more accurately, thereby saving power consumption.

[0035] In a possible implementation, the method further includes: the first paging time information includes a first start time for indicating the start of paging the first terminal device.

[0036] In a possible implementation, the method further includes: the first paging time information also includes first time information corresponding to when a service link between the first terminal devices is unavailable.

[0037] In one possible implementation, the method further includes, when the first data transmission is completed, sending first indication information to the first terminal device, wherein the first indication information indicates that monitoring has stopped or that data transmission is complete. By sending the first indication information, the terminal device can stop monitoring and save power consumption.

[0038] In a possible implementation, the method further includes sending broadcast information, where the broadcast information carries indication information for supporting a store-and-forward operation.

[0039] In a fourth aspect, a communication device is provided for implementing the various methods described above. The communication device includes modules, units, or means corresponding to the methods described above. The modules, units, or means may be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0040] In some possible designs, the communication device may include a transceiver module and a processing module. The transceiver module, which may also be referred to as a transceiver unit, is configured to implement the sending and / or receiving functions of the method of any one of the first to third aspects and any possible implementation thereof. The transceiver module may be composed of a transceiver circuit, a transceiver, a transceiver, or a communication interface. The processing module may be configured to implement the processing functions of the method of any one of the first to third aspects and any possible implementation thereof.

[0041] In some possible designs, the transceiver module includes a sending module and a receiving module, which are respectively used to implement the sending and receiving functions of the method of any one of the first to third aspects above and any possible implementation methods thereof.

[0042] In a fifth aspect, a communication device is provided, comprising: a processor and a communication interface; the communication interface is used to communicate with a module outside the communication device; the processor is used to execute a computer program or instruction so that the communication device executes any of the methods described above.

[0043] In a sixth aspect, a communication device is provided, comprising: at least one processor; the processor is configured to execute a computer program or instruction stored in a memory, so that the communication device performs the method of any of the above aspects. In one possible implementation, the memory may be coupled to the processor, or may be independent of the processor. In another possible implementation, the communication device further includes the memory. Optionally, the memory and the processor are integrated.

[0044] In aspects 4 to 6, the communication device may be the terminal device in the first aspect or any implementation of the first aspect, or a device including the terminal device, or a device included in the terminal device, such as a chip or a chip system. Alternatively, the communication device may be the mobile management network element in the second aspect or any implementation of the second aspect, or a device including the mobile management network element, or a device included in the mobile management network element, such as a chip or a chip system. Alternatively, the communication device may be the access network device in the third aspect or any implementation of the third aspect, or a device including the access network device (e.g., a satellite), or a device included in the access network device, such as a chip or a chip system.

[0045] In a seventh aspect, a communication device is provided (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the functions involved in any of the above aspects or any of its implementation methods.

[0046] In some possible designs, the communication device includes a memory for storing necessary program instructions and data.

[0047] In some possible designs, when the device is a chip system, it can be composed of a chip, or it can also include a chip and other discrete devices.

[0048] It can be understood that when the communication device provided in any one of the fourth to seventh aspects is a chip, the above-mentioned sending action / function can be understood as output, and the above-mentioned receiving action / function can be understood as input.

[0049] In an eighth aspect, a computer-readable storage medium is provided, which stores a computer program or instruction. When the computer program or instruction is run on a communication device, the communication device can execute any of the above aspects or any of its implementation methods.

[0050] In a ninth aspect, a computer program product comprising instructions is provided, which, when executed on a communication device, enables the communication device to execute the method of any of the above aspects or any of its implementations.

[0051] Among them, the technical effects brought about by any implementation method in the fourth to ninth aspects can refer to the technical effects brought about by the corresponding implementation methods in the first to seventh aspects, and will not be repeated here.

[0052] It should be noted that various possible implementations of any of the above aspects can be combined under the premise that the solutions are not contradictory.

[0053] In a tenth aspect, a communication system is provided, comprising a mobility management network element and an access network device. The mobility management network element is configured to execute the method described in the second aspect or any implementation of the second aspect. The first access network device is configured to execute the method described in the third aspect or any implementation of the third aspect.

[0054] In some possible designs, the communication system further includes a first terminal device, wherein the first terminal device is configured to execute the method of the first aspect or any implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG1 is a schematic diagram of a flow chart of data transmission based on a control plane;

[0056] FIG2 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0057] FIG3 is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0058] FIG4 is a schematic diagram of a communication method provided in an embodiment of the present application;

[0059] FIG5 is a schematic diagram of a possible process provided by an embodiment of the present application;

[0060] FIG6 is a schematic diagram of another possible process provided by an embodiment of the present application;

[0061] FIG7 is a schematic diagram of the composition of a communication device provided in an embodiment of the present application;

[0062] FIG8 is a schematic diagram of the hardware structure of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to facilitate understanding of the technical solutions of the embodiments of the present application, a brief introduction to the relevant technologies of the present application is first given as follows.

[0064] 1. Data transmission based on the control plane in CIoT on the ground:

[0065] Taking the fourth generation (4G) mobile communication system as an example, when both the feeder link and the service link are available in the non-terrestrial communication network (NTN), a downlink data transmission process based on the control plane is shown in Figure 1 and includes the following steps:

[0066] 0. User Equipment (UE) is attached to the evolved packet system (EPS) and is in the idle state.

[0067] 1. After receiving the downlink data notification message from the network side, the MME sends a response message (downlink data notification ack message) for the downlink data notification, that is, an acknowledgement message (acknowledge, ACK) for the downlink data notification, notifying that the sent downlink data notification message has been received.

[0068] 2. The MME sends a paging message to the evolved node B (eNodeB / eNB) on each satellite in the tracking area (TA) where the UE is registered, based on the pre-stored ephemeris information, requesting the eNodeB to page the UE over the air interface.

[0069] 3. After receiving the paging message from the MME, the eNodeB pages the UE through the service link.

[0070] 4. Since the UE is in the idle state, upon receiving the paging message, the UE establishes an RRC connection with the eNodeB. Specifically, the UE sends an RRC connection request to the eNodeB. After receiving the RRC connection request, the eNodeB sends an RRC connection establishment message to the UE. After receiving the RRC connection establishment message, the UE sends an RRC connection establishment complete message to the eNodeB. At this point, the RRC connection is considered established. The RRC connection request message includes a non-access stratum (NAS) control plane service request.

[0071] 5. Since the UE is in the idle state, upon receiving the paging message, the UE establishes an RRC connection with the eNode. Specifically, the UE sends an RRC Connection Request to the eNode. After receiving the RRC Connection Request, the eNode sends an RRC Connection Establishment message to the UE. After receiving the RRC Connection Establishment message, the UE sends an RRC Connection Establishment Complete message to the eNode. At this point, the RRC connection is considered established. The RRC Connection Request message includes a non-access stratum (NAS) control plane service request.

[0072] 6. The eNodeB sends the UE's NAS control plane service request to the MME. Based on the NAS control plane service request, the MME determines that the UE paging is successful and can send downlink data to the UE.

[0073] 7. The MME receives downlink data from the UE on the network side.

[0074] 8-9. The MME performs data encryption and integrity protection on the downlink data and sends the downlink data to the eNodeB that successfully pages the UE.

[0075] 10. The eNodeB sends downlink data to the UE via an RRC downlink message.

[0076] It can be understood that Figure 1 is a schematic diagram of the process when it is applied to the 4G system. If the process shown in Figure 1 is applied to the fifth generation (5G) mobile communication system or other communication systems, the names of the devices in the above text can also be replaced with the names in the 5G system or other communication systems.

[0077] However, in NTN scenarios, there may be discontinuous satellite coverage and feeder links. A user device may be out of satellite coverage or, even if it is covered by a satellite, obstructed by an object, resulting in an unavailable service link between the user device and the satellite. In this case, the user device cannot communicate with the satellite via the service link. The user device can determine its unavailability period. For example, the user device can use preset ephemeris information or satellite coverage information to calculate when it is within satellite coverage, thereby determining the unavailability period. For another example, the user device can determine the unavailability period by monitoring satellite broadcast information over a period of time. The unavailability period can correspond to different satellites, meaning the user device determines the unavailability period for a specific satellite. The unavailability period can also indicate that the user device cannot communicate with the satellite it wishes to monitor (or requests to monitor) during this period, meaning that the user device is not within the coverage of the satellite it wishes to monitor (or requests to monitor). Furthermore, the unavailability period can also indicate that the user device cannot communicate with any satellite during this period, meaning that the user device is not within the coverage of any satellite. Similarly, the feeder link between the satellite and the MME also has the same problem. Therefore, applying the process shown in Figure 1 in the NTN scenario is prone to the following defects:

[0078] When the base station on the satellite needs to interact with the equipment on the ground through the feeder link / service link at a certain stage, if the required link is unavailable at this time, the base station cannot complete the corresponding interaction. If the base station gives up trying to interact, the process cannot continue, and the data cannot be sent from the core network to the terminal device. For example, if the base station decides to wait for the feeder link to be restored to continue the process (such as step 6), and after the base station waits for the feeder link to be restored to complete the process at this stage, the service link may be unavailable at this time, and the base station needs to continue waiting for the service link to be restored. In this case, communication between the UE and the network is almost impossible to achieve, and the data transmission efficiency is very low.

[0079] To solve this problem, the satellite can be configured to support storage and forwarding (S&F) operations. That is, the UE's current serving satellite can provide the UE with a communication service (storage and forwarding information) operating mode when it is not connected to the ground network (ground station) through a feeder link. For the uplink, "storage" refers to caching uplink data from the UE when the service link is available, and "forwarding" refers to forwarding the stored uplink information to the ground network when the feeder link is available. For the downlink, "storage" refers to caching downlink data from the ground network when the feeder link is available, and "forwarding" refers to forwarding the stored downlink data to the UE when the service link is available.

[0080] This enables communication even with discontinuous satellite coverage and feeder links, and improves network interchange efficiency. This makes it possible for some communication applications, particularly narrowband Internet of Things (NB-IoT) communications in remote areas. While ensuring communication with the network, UEs can also improve their power consumption requirements.

[0081] Therefore, in scenarios where satellite coverage is discontinuous and the feeder link is discontinuous, how to ensure UE communication while meeting the UE's low power consumption requirements is a problem waiting to be solved. Based on this problem, the present application provides a communication method, apparatus, and system that can send data from the core network to the terminal device in scenarios where the feeder link is discontinuous. Compared with the process shown in Figure 1, this can reduce the UE's power consumption and meet the UE's power saving requirements.

[0082] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Among them, in the description of the present application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship. For example, A / B can represent A or B; "and / or" in the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. At the same time, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0083] In the embodiment of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the first indication information or the second indication information below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein the other information and the information to be indicated have an association relationship. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can also be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

[0084] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of the various indication methods can be referred to the prior art and will not be repeated herein. As can be seen from the above, for example, when it is necessary to indicate multiple information of the same type, there may be a situation where the indication methods for different information are different. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0085] It should be understood that the information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in the embodiments of this application. The sending period and / or sending time of these sub-information can be predefined, for example, predefined according to a protocol, or can be configured by the transmitting device by sending configuration information to the receiving device.

[0086] In an embodiment of the present application, "pre-definition", "pre-defined", "pre-configured" or "pre-configured" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in the device. For example, it can be burned into the device when the device leaves the factory. The embodiment of the present application does not limit its specific implementation method. Among them, "saving" can mean saving in one or more memories. The one or more memories can be set separately or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories can also be partially set separately and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, which is not limited by the embodiment of the present application.

[0087] The "protocol" involved in the embodiments of the present application may refer to a protocol family in the communication field, a standard protocol with a similar protocol family frame structure, or a related protocol used in future communication systems. The embodiments of the present application do not make specific limitations on this.

[0088] In the embodiments of the present application, descriptions such as "when...", "in the case of...", "if" and "if" all mean that the device will perform corresponding processing under certain objective circumstances. It does not limit the time, nor does it require the device to perform judgment actions when implemented, nor does it mean that there are other limitations.

[0089] In the embodiment of the present application, "sending information to... (taking a terminal device as an example)" can be understood as the destination end of the information being the terminal device. This can include sending information directly or indirectly to an anchor network element. "Receiving information from... (taking a mobile management network element as an example)" can be understood as the source end of the information being a mobile management network element, which can include receiving information directly or indirectly from a mobile management network element. The information may be processed as necessary between the source and destination ends of the information transmission, such as format changes, but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood similarly and will not be repeated here.

[0090] The technical solution provided in this application can be used in various communication systems, which may be a third generation partnership project (3GPP) communication system, for example, a 4G mobile communication system, a long term evolution (LTE) system, a 5G mobile communication system and its evolution system, an NTN system, a multiple-input multiple-output (MIMO) system, a vehicle to everything (V2X) system, a system of hybrid networking of LTE and new radio (NR), or a device to device (D2D) system, a machine to machine (M2M) communication system, IoT (such as cellular internet of things (CIoT)), and other communication systems. In addition, the term "system" and "network" can be used interchangeably.

[0091] It should be noted that the network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0092] FIG2 is a schematic diagram of a possible, non-limiting communication system applicable to embodiments of the present application. As shown in FIG2 , the communication system 10 includes a radio access network (RAN) 100. The RAN 100 includes at least one access network device 110 and at least one terminal device (e.g., 70a-70c in FIG2 , collectively referred to as 70). The RAN 100 may also include other devices, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG2 ). The terminal device 70 is connected to the access network device 110 wirelessly, for example, via a service link.

[0093] As shown in FIG2 , the communication system 10 also includes a core network (CN 200 in FIG2 ). Access network equipment 110 can be connected to CN 200 wirelessly, such as via a feeder link. The core network equipment in CN 200 and the access network equipment 110 in RAN 100 can be different physical devices, or they can be the same physical device that integrates core network logical functions and radio access network logical functions.

[0094] If the communication system 10 is used in an NTN scenario, 3a and 3b in FIG3 are schematic diagrams of possible, non-limiting application scenarios provided by embodiments of the present application. In the application scenario shown in 3a, access network equipment is deployed on a satellite, and no inter-satellite links (i.e., communication links between satellites) exist between satellites. In the application scenario shown in 3b, access network equipment is deployed on a satellite, and inter-satellite links exist between satellites. In the application scenarios shown in 3a and 3b, the access network equipment on the satellite can communicate with a gateway on the ground via a feeder link, thereby further communicating with the core network on the ground. The access network equipment on the satellite can also communicate with terminal equipment on the ground via a service link.

[0095] Among them, if the embodiment of the present application is applied in an IoT system, the terminal devices in 3a and 3b in Figure 3 can also be called IoT devices.

[0096] Optionally, if the communication system 10 is used in an NTN scenario, while the access network equipment is located on a satellite, some core network elements may also be deployed on the satellite. This may include some core network elements, or some logical functions of some core network elements. The satellite where some core network elements are located may be the same satellite as the satellite where the access network equipment is located, or different satellites. If some core network elements and the access network equipment are located on different satellites, some core network elements may communicate with the access network equipment via intersatellite links.

[0097] For example, if the embodiment of the present application is applied to a 4G mobile communication system, the MME may be located on a satellite. If the embodiment of the present application is applied to a 5G mobile communication system, the access and mobility management function (AMF) may be located on a satellite.

[0098] The access network device in the embodiment of the present application refers to a RAN node (or device) that connects a terminal device to a wireless network. In some network architectures, the access network device may be a base station. Currently, examples of some access network devices include: the next generation Node B (gNB), a transmission reception point (TRP), an eNodeB, a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home evolved NodeB (HNB), a base band unit (BBU), or a wireless fidelity (Wifi) access point (AP).

[0099] In addition, in a network structure, multiple access network devices collaborate to assist terminal devices in achieving wireless access, and different access network devices respectively implement part of the functions of the base station. For example, the access network device can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0100] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in an open access network (open RAN, O-RAN or ORAN), CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0101] All or part of the functions of the access network device in this application may also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (such as a cloud platform). The access network device in this application may also be a logical node, logical module, or software that can implement all or part of the functions of the access network device.

[0102] The terminal device in the embodiments of the present application may also be referred to as a terminal, UE, mobile station (MS), mobile terminal, etc., and is a device with wireless transceiver capabilities. The terminal device can be widely used in various scenarios, such as vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical surgery, smart grid, smart home, smart office, smart bracelet, smart city, etc. Currently, some examples of terminal devices include: mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of the present application do not limit the device form of the terminal device.

[0103] In the embodiments of this application, core network elements / core network devices refer to devices in the core network that provide service support for terminal devices. Currently, some examples of core network elements include MME elements and AMF elements, which are not listed here. Among them, MME elements can be responsible for access and mobility management of terminal devices in 4G systems. AMF elements can be responsible for access and mobility management of terminal devices in 5G systems.

[0104] In the embodiment of the present application, a network element may also be referred to as an entity or a functional entity. For example, an MME network element may also be referred to as an MME entity or an MME functional entity.

[0105] It should be noted that the message names between network elements or the names of parameters in the messages in the following embodiments of the present application are only examples, and other names may be used in specific implementations. The embodiments of the present application do not specifically limit this.

[0106] It should be noted that, in the embodiments of the present application, “cache” and “store” are the same concept and can be used interchangeably.

[0107] It is understood that in the embodiments of the present application, each network element may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0108] As shown in Figure 4, a communication method is provided for an embodiment of the present application. Figure 4 illustrates the method by taking the mobile management network element and the first access network device as the execution subjects of the interaction diagram as an example, but the present application does not limit the execution subjects of the interaction diagram. For example, the mobile management network element in Figure 4 can also be a module such as a chip, a chip system, or a processor applied to the mobile management network element, and can also be a logical node, a logical module, or software that can realize all or part of the functions of the mobile management network element; the first access network device in Figure 4 can also be a module such as a chip, a chip system, or a processor applied to the first access network device, and can also be a logical node, a logical module, or software that can realize all or part of the functions of the first access network device.

[0109] The mobility management network element in the embodiments of the present application can perform mobility management on the terminal device. It can have different names in different communication systems, and the embodiments of the present application are not limited to this. For example, in a 4G communication system, the mobility management network element can be an MME network element. In a 5G communication system, the mobility management network element can be an AMF network element. In other communication systems, the mobility management network element can also have other names, which does not affect the application of the communication method of the embodiments of the present application.

[0110] As shown in FIG4 , the communication method includes steps S401 to S410:

[0111] S401. A first UE determines first information and sends the first information to a mobility management network element. The first information is used to determine monitoring information.

[0112] When a service link between a first UE and a satellite is available, the first UE sends a first request to an access network device on the satellite. When a feeder link between a satellite and a mobility management network element is available, the access network device on the satellite sends the first request to the mobility management network element. The availability of a service link or feeder link between devices can be understood as meaning that the corresponding device (e.g., the first UE or the mobility management network element) is within the coverage of the satellite where the access network device is located. Accordingly, when the corresponding device is not within the coverage of the satellite where the access network device is located, the service link or feeder link between the devices is unavailable.

[0113] The first information is used to determine monitoring information. Specifically, the first information is determined by the first UE, and the first information corresponds to at least one S&F satellite that the first UE requests to monitor or at least one monitoring period of the first UE.

[0114] In one case, the first information is requested monitoring information, for example, it may be specifically requested monitoring mode information, requested monitoring time information, requested monitoring satellite information, etc. Taking the requested monitoring mode information as an example, the requested monitoring mode information corresponds to at least one S&F satellite. The requested monitoring mode information may indicate the monitoring mode requested by the first UE, for example, the requested monitoring mode information includes monitoring a fixed single S&F satellite, monitoring at least one S&F satellite providing coverage, and monitoring all S&F satellites providing coverage. In this case, the first UE may not determine the specific satellite, or preset ephemeris information or satellite coverage information, and the first information may be sent to the mobility management network element, and the mobility management network element may determine the specific satellite to be monitored by the first UE. The first UE may also preset ephemeris information or satellite coverage information and determine the first information based on this information. The first UE may determine the requested monitoring mode information based on power saving requirements and / or communication requirements (for example, data transmission delay requirements).

[0115] Furthermore, the first information determined by the first UE may also include at least one identifier, each of the at least one identifier corresponding to a satellite. Through the identifier, the first UE can indicate a satellite to be activated or a satellite to be deactivated. The first UE determines the at least one identifier based on preset information, historical monitoring information of the satellite, and information from the core network. Specifically, the at least one identifier can be the identification information (ID) of the satellite, or the identification information of an access network device deployed on the satellite. Optionally, the first information includes both the identifier of the satellite requested by the first UE to be activated and the satellite requested to be deactivated by the first UE.

[0116] In another case, the first information corresponds to the requested listening period, and the first information may specifically be the unavailable period of the first UE and / or the listening period of the first UE. Exemplarily, the first UE confirms the first information based on preset ephemeris information or satellite coverage information; the first UE may also confirm the satellite that supports S&F operations based on the broadcast information received from the satellite, and then confirm the first information based on the message actually received from the satellite, the position of the first UE, or the preset ephemeris information or satellite coverage information. Specifically, the first information may specifically include start time information, end time information or duration information. Optionally, the first information may also include multiple start time information, end time information or duration information, and the first information corresponds to multiple requested listening periods. Preferably, the first information also includes periodic information, that is, the requested listening period is repeated according to the periodic information. The periodic information may be a fixed value, or it may be a column of values ​​that are periodically traversed to correspond to different listening periods.

[0117] Taking the unavailable period of the first UE as an example, the first UE can calculate the position of the corresponding satellite and the time of the position based on preset ephemeris information, and determine when the service link with the satellite is available. Based on the satellite's position, the first UE can determine an unavailable period, during which the service link of the first UE is unavailable. The unavailable period also indicates the time when the first UE monitors. The first UE can also determine the unavailable period by monitoring the satellite or receiving broadcast information from the satellite. Alternatively, the first UE can determine whether the satellite is an S&F satellite based on the satellite's broadcast information, and determine the unavailable period with respect to the S&F satellite as the unavailable period of the first UE.

[0118] Possibly, the first UE may adjust the unavailable period according to power saving requirements and / or communication requirements (eg, data transmission delay requirements) so that the unavailable period corresponding to the first information includes a partial satellite coverage period.

[0119] Taking the first information as an example of a monitoring period of a first UE, during the monitoring period of the first UE, the first UE is under the coverage of at least one S&F satellite, and a service link between the first UE and the at least one S&F satellite is available. Furthermore, the first UE can adjust the monitoring period of the first UE based on power saving requirements and / or communication requirements (e.g., data transmission delay requirements). That is, when the first UE has a higher power saving requirement or a lower communication requirement, the first UE shortens the monitoring period of the at least one S&F satellite. Specifically, the first UE stops monitoring when it is under the coverage of the at least one S&F satellite.

[0120] In a possible implementation, the first information includes both the unavailable period of the first UE and the monitoring period of the first UE.

[0121] The first UE may carry the first information via a first request and send it to the mobility management network element. The first request may be an Attach request or a Tracking Area Update (TAU) request message. For example, in 5G, the first request may also be a Registration request message.

[0122] S402: The mobility management network element determines monitoring information according to the first information.

[0123] Since the mobile management network element can obtain more information (such as base station capability information, satellite capability information, network load information, etc.), the mobile management network element determines the monitoring information based on not only the first information but also other information obtained. For example, the other information may include one or more of the first UE's request, the first UE's subscription information, the first UE's context, the first UE's location, ephemeris information, satellite coverage information, local configuration of the mobile management network element, the maximum number of paging times, base station capabilities, etc.

[0124] The monitoring information is used to instruct the first UE to monitor, and may include a satellite identifier for monitoring, monitoring period information, etc. Taking the first information as the aforementioned mode information for requesting monitoring as an example, the mobility management network element may determine at least one identification information based on the first information and the aforementioned other information, and the at least one identification information corresponds to the S&F satellite monitored by the first UE. The mobility management network element stores the at least one identification information, exemplarily in an S&F satellite monitoring list corresponding to the first UE. The satellites in the list are satellites that the UE needs to monitor and are also satellites that can support S&F operations. If the mobility management network element has already stored an S&F satellite monitoring list corresponding to the first UE, the mobility management network element updates the list.

[0125] Taking the listening period corresponding to the request of the first information as an example, the mobile management network element can determine at least one listening period based on the first information and the aforementioned other information. The mobile management network element can determine the unavailable period corresponding to the first UE, and the unavailable period can indicate at least one listening period, that is, the period of listening outside the unavailable period is at least one listening period. The mobile management network element can also determine the listening period corresponding to the first UE. The mobile management network element can also determine the unavailable period and the listening period corresponding to the first UE. The specific content can be referred to the description in S401 and will not be repeated here. Optionally, the mobile management network element can periodically maintain the unavailable period corresponding to the first UE and / or the listening period corresponding to the first UE based on the determined first information.

[0126] S403: The mobility management network element sends the determined monitoring information to the first UE.

[0127] The mobility management network element sends the monitoring information to the access network device via the feeder link. The access network device may be different from the access network device in step S401 (i.e., the satellite where the access network device in step S401 is located no longer covers the mobility management network element). The access network device sends the monitoring information to the first UE via the service link. The feeder link and the service link may not be available at the same time.

[0128] Exemplarily, the mobility management network element updates at least one identification information in the UE context or updates the S&F satellite monitoring list corresponding to the first UE, and sends it to the first UE.

[0129] The mobility management network element may carry the monitoring information in a first response and send it to the first UE. The first response corresponds to the first request in S401. The first response may be an attach accept message or a tracking area update (TAU) accept message. For example, in a 5G system, the first response may be a registration receive message or a registration complete message.

[0130] S404: The mobility management network element receives downlink data corresponding to the first UE from the core network and determines the first satellite.

[0131] The mobility management network element receives downlink data from the first UE and determines a first satellite with which communication is required. The downlink data may be mobile terminated data (MT Data). For example, the mobility management network element determines, based on information about the first UE (e.g., identification or location information), that the downlink data needs to be sent via an S&F satellite. The mobility management network element may determine the first satellite based on the determined monitoring information.

[0132] Optionally, when the monitoring information is a monitoring list of S&F satellites for the first UE, the mobility management network element selects a first satellite in the list based on the list. The first satellite may be the satellite in the list that covers the first UE the earliest, or the satellite in the list that has covered the first UE the longest. The mobility management network element may determine the first satellite based on a downlink data volume, a communication requirement, a power saving requirement of the first UE, satellite capability information, and the like.

[0133] Optionally, when the monitoring information is the unavailable period of the first UE or the monitoring period of the first UE, the mobility management network element determines the first satellite based on the monitoring information and at least one of the ephemeris information, satellite coverage information and the location information of the first UE, and the first satellite supports S&F operations.

[0134] S405: The mobility management network element sends downlink data to the first satellite. This can also be understood as the mobility management network element sending downlink data to the access network device on the first satellite.

[0135] Optionally, in addition to sending the downlink data, the mobility management network element further sends first indication information, where the first indication information is used to instruct the first satellite to use the S&F operation. Specifically, the first indication information may instruct the first satellite to store the downlink data.

[0136] Optionally, the mobility management network element may further send second indication information, where the second indication information corresponds to the paging period of the first satellite. The mobility management network element determines the paging period of the first satellite based on the first satellite, ephemeris information or satellite coverage information, and the location information of the first UE. Optionally, the mobility management network element may further determine the paging period of the first satellite based on considerations such as the energy saving requirements of the first satellite and the received first information. Exemplarily, the second indication information may be paging period information, specifically including at least two of start time information, duration information, and end time information. The second indication information may also be paging timing information, which indicates that after the first satellite covers the first UE (i.e., the first satellite reaches the tracking area (TA) or tracking area identifier (TAI) list where the first UE is located), the first satellite performs paging according to the paging timing information. For example, the first satellite may start a timer and page the first UE before the timer expires. The second indication information may also be an unavailable period of the first UE stored in the mobility management network element, and the first satellite may perform paging based on the unavailable period. By determining the paging period of the first satellite, the mobility management network element can enable the first satellite to save energy consumption and avoid unnecessary paging and broadcasting.

[0137] Exemplarily, the mobility management network element sends a first paging request to the first satellite, where the first paging request carries at least one of the downlink data, the first indication information, and the second indication information.

[0138] S406: The first satellite stores the downlink data.

[0139] The first satellite supports S&F operation, and because the service link between the first satellite and the first UE is currently unavailable, the first satellite stores the received downlink data. Alternatively, the first satellite stores the downlink data according to the first indication information.

[0140] S407: The first UE monitors according to the received monitoring information and receives a paging signal from the first satellite.

[0141] The first UE receives monitoring information from the mobility management network element, stores and maintains corresponding information, and performs monitoring according to the monitoring information.

[0142] Exemplarily, when the monitoring information is the S&F satellite monitoring list of the first UE, the first UE starts monitoring paging only when the first satellite included in the list provides a service link. The first UE can determine the time of entering the coverage area of ​​the first satellite based on preset ephemeris information or satellite coverage information and the S&F satellite monitoring list, and start monitoring. In one implementation, when the first UE determines that it is under the coverage of the S&F satellite (for example, by determining whether the satellite's broadcast information carries indication information that supports S&F operations), it can further determine whether the satellite is included in the S&F satellite monitoring list. If so, the first UE monitors the paging; otherwise, the first UE does not monitor the paging.

[0143] Exemplarily, when the monitoring information is the unavailable period of the first UE or the monitoring period of the first UE, the first UE periodically maintains the unavailable period or the monitoring period and determines a period for monitoring paging.

[0144] The first satellite starts paging when covering the first UE; paging may also be performed according to the received second indication information.

[0145] S408: The first UE performs downlink data transmission with the first satellite.

[0146] The first UE establishes a service link with the first satellite and transmits downlink data via the service link. When the service link is available, the first satellite sends the downlink data to the first UE. Optionally, the first UE also sends uplink data via the service link.

[0147] S409. Optionally, the first satellite sends third indication information to the first UE, where the third indication information instructs to stop monitoring.

[0148] Because the first satellite stores downlink data and the feeder link between the first satellite and the mobility management network element is unavailable, the first satellite determines that the stored downlink data has been transmitted. The first satellite may send third indication information to the first UE, instructing the first UE to stop monitoring paging during the remaining time provided by the first satellite. Exemplarily, the third indication information is a sleep indication or a stop indication. Alternatively, the third indication information indicates that the first satellite has completed data transmission, such as a downlink data transmission completion indication. The first UE may confirm the completion of data transmission and no longer receive new downlink data from the first satellite based on the third indication information.

[0149] S410: The first UE stops monitoring.

[0150] The first UE determines to stop monitoring paging during the remaining coverage time of the first satellite based on ephemeris information or satellite coverage information. After establishing a connection with the first satellite, the first UE completes reception of downlink data and determines not to monitor paging during the remaining coverage time. Exemplarily, the first UE determines that the first satellite is an S&F satellite, meaning that the first satellite stores limited downlink data. The first UE completes reception of the downlink data stored by the first satellite by establishing this connection, thereby determining not to monitor paging.

[0151] The first UE may also stop monitoring according to the third indication information.

[0152] The first UE stopping monitoring may be that the first UE decides not to monitor paging in the discontinuous reception cycle, or the first UE turns off an access layer function, etc.

[0153] By stopping monitoring early, the first UE can save more power consumption.

[0154] Through the method of this embodiment, the first UE negotiates monitoring information with the mobility management network element. Both the first UE and the mobility management network element store and / or periodically maintain the monitoring information. This allows the UE to complete downlink data reception and save further energy consumption even when the service link and feeder link are not available at the same time. Furthermore, the mobility management network element can also instruct the base station on the satellite to reduce the paging time based on the monitoring information, thereby saving energy consumption of the base station on the satellite.

[0155] The embodiments of the present application do not limit the specific implementation method of the mobility management network element determining whether the connection between the access network device and the terminal device is available. The following uses the example of determining whether the connection between the first access network device and the first terminal device is available to introduce a possible implementation method provided by the embodiments of the present application.

[0156] The mobility management network element determines whether the first terminal device is within the coverage range corresponding to the first access network device (which may be the coverage range of the satellite where the first access network device is located, or the coverage range of the first access network device, hereinafter referred to as the coverage range) based on the satellite coverage availability information corresponding to the first access network device and the location information of the first terminal device. When the first terminal device is within the coverage range, the mobility management network element determines that the communication connection between the first access network device and the first terminal device is available. When the first terminal device is not within the coverage range, the mobility management network element determines that the communication connection between the first access network device and the first terminal device is unavailable.

[0157] The location information of the first terminal device may include information indicating the area where the first terminal device is located. For example, the location information of the first terminal device may include identification information of the tracking area (TA) where the first terminal device is located. For another example, the location information may include a tracking area list (TA list) where the tracking area where the first terminal device is located is located. Alternatively, the location information of the first terminal device may also be information such as the latitude and longitude information of the first terminal device.

[0158] The embodiments of the present application do not limit the specific manner in which the mobile management network element obtains the location information of the first terminal device. For example, the mobile management network element may obtain information about the tracking area in which the first terminal device is located when the first terminal device enters an idle state. For another example, the mobile management network element may obtain information about the updated tracking area based on the tracking area update (TAU) process of the first terminal device. The mobile management network element may use the obtained at least one item of tracking area information as the location information of the first terminal device.

[0159] The satellite coverage availability information corresponding to the first access network device may include a mapping relationship between the coverage range of the satellite where the first access network device is located and time. For example, the satellite coverage availability information corresponding to the first access network device may include the following mapping relationship: at 7:00, the coverage range of the satellite where the first access network device is located is area 1; at 8:00, the coverage range of the satellite where the first access network device is located is area 2, and so on.

[0160] Optionally, if the first access network device and one or more other access network devices are located on the same satellite, the satellite coverage availability information corresponding to the first access network device may include a mapping relationship between the coverage range of each access network device on the satellite and time. Alternatively, the mapping relationship between the coverage range of the first access network device and time may also be included.

[0161] The embodiments of the present application do not limit the specific manner in which the mobility management network element obtains the satellite coverage availability information corresponding to the first access network device. For example, the mobility management network element may pre-configure the satellite coverage availability information corresponding to the first access network device. In another example, the mobility management network element may calculate the satellite coverage availability information corresponding to the first access network device based on the ephemeris information of the first access network device.

[0162] In one possible scenario, for determining the first access network device, if there are currently multiple access network devices whose communication connections with the mobile management network element are available and whose communication connections with the first terminal device are unavailable, the mobile management network element can select one access network device from them as the first access network device.

[0163] The embodiments of the present application do not limit the specific implementation method by which the first access network device determines whether the communication connection between the first access network device and the first terminal device is available. For example, the first paging message received by the first access network device may carry the location information of the first terminal device. The first access network device may determine whether the first access network device is within the coverage range of the first access network device based on the location information of the first terminal device and the coverage range of the first access network device. If it is within the coverage range, it can be determined that the communication connection between the first access network device and the first terminal device is available. If it is not within the coverage range, it can be determined that the communication connection between the first access network device and the first terminal device is unavailable.

[0164] The embodiments of the present application do not restrict how the mobility management network element determines whether the downlink data of the first terminal device can be cached in the mobility management network element. In one possible implementation, the mobility management network element can determine whether the downlink data of the first terminal device supports transmission via a store and forward operation. If so, the mobility management network element can determine that the downlink data of the first terminal device can be cached in the mobility management network element.

[0165] Among them, storage and forwarding can be understood as, in the scenario where the feeder link of the NTN network is discontinuous, the data is first cached in the mobile management network element located on the satellite, and then forwarded between the terminal device and the ground core network through the mobile management network element.

[0166] As shown in Figure 5, a communication method is provided in an embodiment of the present application. In Figure 5, the first network is taken as a 4G network as an example, that is, the access network device of the first network is an evolved NodeB (eNB), and the first network element of the first network is a mobility management entity (MME). However, the present application does not limit the execution subject of this interaction diagram. For example, the mobility management network element in Figure 5 can also be a module such as a chip, a chip system, or a processor applied to the mobility management network element, or a logical node, a logical module, or software that can implement all or part of the functions of the mobility management network element; the first access network device in Figure 5 is an access network device set on a satellite, or it can be a module such as a chip, a chip system, or a processor applied to the first access network device, or it can be a logical node, a logical module, or software that can implement all or part of the functions of the first access network device. The mobility management network element in the embodiment of the present application can perform mobility management on the terminal device, and can have different names in different communication systems, which is not limited by the embodiment of the present application. For example, in a 4G communication system, the mobility management network element can be an MME network element. In the 5G communication system, the mobility management network element may be an AMF network element. In other communication systems, the mobility management network element may also have other names, which does not affect the application of the communication method of the embodiment of the present application.

[0167] As shown in FIG5 , the communication method includes steps S501 to S512:

[0168] S501. An access network device receives a first request from a first UE. The first request carries first indication information, and the first indication information is used to determine monitoring information.

[0169] Specifically, the first indication information indicates the S&F monitoring information requested by the first UE. In an achievable method, the first indication information includes first mode information, which indicates the satellite monitoring mode requested by the first UE, such as only monitoring the paging of a fixed single satellite, monitoring the paging of satellites that partially provide coverage, monitoring the paging of all satellites that provide coverage, etc.

[0170] Optionally, the first indication information also includes at least one identification information, and the at least one identification information corresponds to at least one satellite providing coverage. The first UE can request activation or deactivation of the corresponding at least one satellite providing coverage through the at least one identification information. The satellite providing coverage that the first UE requests to activate is the satellite that the first UE requests to monitor; the satellite providing coverage that the first UE requests to deactivate is the satellite that the first UE does not want to continue monitoring. The at least one identification information uniquely identifies the corresponding satellite. Specifically, the at least one identification information can be an identifier (ID) of the satellite or identification information of an access network device set on the satellite.

[0171] In a possible implementation manner, the first request is an attach request or a tracking area update (TAU) request message.

[0172] S502: The access network device sends the first request to the mobility management network element.

[0173] Specifically, when the feeder link is available, the access network device sends the first request to the mobility management network element. At this time, the service link between the access network device and the first UE is disconnected.

[0174] S503: The mobility management network element determines at least one first identifier according to the first request, where the at least one first identifier corresponds to at least one first satellite, and the first satellite supports S&F operations.

[0175] Specifically, the mobility management network element determines the at least one first identifier based on the received first indication information. Preferably, the mobility management network element determines, based not only on the received first indication information but also on acquired second information, such as subscription information of the first UE, local configuration of the mobility management network element, policy information (e.g., maximum number of paging times), access network device capability information, etc., that the at least one satellite monitored by the first UE corresponding to the at least one first identifier and the access network device configured thereon supports S&F.

[0176] After the mobility management network element determines the satellite monitored by at least one first UE corresponding to at least one first identifier, it can be saved as an updated S&F satellite monitoring list of the first UE. The satellites in the list are the satellites that the first UE needs to monitor, and the satellite (or the access network equipment set on the satellite) supports caching and forwarding the downlink data of the first UE.

[0177] S504: In response to the first request, the mobility management network element sends a first response to the access network device, where the first response message includes the at least one first identifier.

[0178] The access network device may be different from the access network device in step S502, that is, the satellite where the access network in step S502 is configured no longer covers the mobility management network element.

[0179] Exemplarily, the first response is an attach accept or tracking area update (TAU) accept message.

[0180] S505: The access network device sends the first response to the first UE.

[0181] When the service link between the access network device and the first UE is available, the first response is sent. At this time, the feeder link between the access network device and the mobility management network element may have been disconnected.

[0182] S506: The first UE receives and stores the at least one first identifier.

[0183] Exemplarily, the first UE receives and saves the S&F satellite monitoring list.

[0184] S507: The mobility management network element receives downlink data corresponding to the first UE from the core network and determines the first satellite.

[0185] Specifically, after receiving downlink data corresponding to the first UE, the mobility management network element determines a first satellite based on the at least one first identifier and sends the downlink data to the first satellite. The first satellite supports S&F operations and can cache the downlink data. Exemplarily, the first satellite is the satellite that earliest covers the first UE among the satellites corresponding to the at least one first identifier.

[0186] S508: The mobility management network element sends the downlink data to the first satellite

[0187] Optionally, the downlink data is carried by a paging request.

[0188] S509: The first UE monitors according to the at least one first identifier carried in the first response message, and receives the paging from the first satellite.

[0189] The first satellite pages the first UE when the first UE is covered (or the service link is available) according to the downlink data sent by the mobility management network element.

[0190] The first UE monitors the first satellite based on at least one first identifier while being covered by the first satellite, one of the at least one first identifier corresponding to the first satellite. Exemplarily, the first UE may determine whether it is covered by the first satellite based on preset ephemeris information. Exemplarily, the first UE may determine, based on a broadcast message from the satellite, that the satellite is one of the satellites corresponding to the at least one first identifier.

[0191] Optionally, the first UE determines that it is under the coverage of the first satellite based on the received at least one first identifier and pre-configured ephemeris information, and monitors the first satellite when it is under the coverage of the first satellite.

[0192] Optionally, the first UE determines whether the currently monitored satellite is the first satellite according to the broadcast message.

[0193] The first UE receives a paging message from an access network device set up on a first satellite. Specifically, a feeder link between the first satellite and the mobility management network element is unavailable, and a service link between the first satellite and the first UE is available.

[0194] S510: The first UE receives downlink data buffered by the first satellite.

[0195] S511. A first satellite sends a sleep indication to a first UE.

[0196] The first satellite determines that the cached downlink data has been transmitted, and sends an indication message to the first UE. The indication message may be a sleep indication, indicating that the downlink data transmission of the first UE is complete or instructing the first UE to stop monitoring. Optionally, the indication message may be carried in a Radio Resource Control (RRC) connection release message.

[0197] S512: The first UE stops monitoring the first satellite.

[0198] After the first UE completes receiving the downlink data from the first satellite, it stops monitoring the first satellite during the remaining coverage time of the first satellite. The first UE may stop monitoring the first satellite according to the received sleep indication.

[0199] In another possible implementation, the first UE determines that the first satellite has completed downlink data transmission and stops monitoring the first satellite. Specifically, if no new downlink data is received from the first satellite within a first time period of receiving downlink data from the first satellite, the first UE determines that the first satellite has completed downlink data transmission and stops monitoring the first satellite. Preferably, the first UE stops monitoring the first satellite after establishing a single connection with the first satellite.

[0200] Through the method of this embodiment, the first UE can negotiate with the core network for monitored S&F satellites, thereby reducing the number of monitored satellites and achieving energy conservation. Furthermore, by allowing the first UE to stop monitoring paging during the remaining coverage time of a satellite after determining that the satellite has completed downlink data transmission, the time the first UE monitors paging when a service link is available can be further reduced, thereby improving energy conservation.

[0201] As shown in FIG6 , another communication method provided in an embodiment of the present application specifically includes steps S601 to S611:

[0202] S601: An access network device receives a first request from a first UE. The first request carries first indication information, and the first indication information is used to determine monitoring period information.

[0203] Specifically, the first indication information includes the unavailable period of the first UE. Specifically, during the unavailable period of the first UE, the service link of the first UE is unavailable, that is, the first UE cannot connect to any satellite through the service link. It can also be understood that the first UE is not under the coverage of any satellite. The first UE can determine the unavailable period based on preset ephemeris information or satellite coverage information. The first UE can also determine the unavailable period based on whether it monitors the satellite's broadcast message. In an implementable manner, the unavailable period of the first UE can be confirmed by start time information, end time information or duration information. Optionally, multiple information can also be used to confirm the unavailable period of the first UE. Preferably, the unavailable period of the first UE also includes periodic information, that is, the first UE repeatedly experiences unavailable periods. The periodic information may be a fixed value, or it may be a column of values ​​that is periodically traversed to represent different unavailable periods of the first UE.

[0204] Optionally, the first UE determines a first unavailable period for the first UE. During this first unavailable period, the first UE's service link is unavailable, meaning that the first UE cannot connect to any satellite via the service link. This can also be understood as the first UE not being within the coverage of any satellite. The first UE may also determine the first unavailable period based on preset ephemeris information or satellite coverage information. The first UE may also determine the unavailable period based on whether it monitors satellite broadcast messages. The first UE further determines a second unavailable period based on the first unavailable period and power saving requirements. The second unavailable period includes the first unavailable period and a third period. During this third period, the first UE is within the coverage of a satellite, but due to power saving requirements, the first UE decides not to monitor during this third period. Therefore, the second unavailable period determined includes both the first unavailable period and the third period. Optionally, the third period is variable. When the first UE's power saving requirements are high, the first UE determines the third period to be longer; when the first UE's power saving requirements are low, the first UE determines the third period to be shorter. Therefore, the second unavailable period is also variable.

[0205] Furthermore, the first indication information includes, in addition to the unavailable period of the first UE, a desired listening period of the first UE. The desired listening period can also be understood as a listening period to be negotiated. Specifically, the first UE can determine the desired listening period based on power saving requirements. The desired listening period is included in the period other than the unavailable period of the first UE.

[0206] Specifically, the expected listening period can be confirmed by start time information, end time information, or duration information. Optionally, multiple pieces of information can be used to confirm the expected listening period of the first UE. Preferably, the expected listening period of the first UE also includes periodic information, which may be a fixed value or a list of values ​​that are periodically traversed to represent different expected listening periods of the first UE.

[0207] In a possible implementation manner, the first request is an attach request or a tracking area update (TAU) request message.

[0208] S602: The access network device sends the first request to the mobility management network element.

[0209] Specifically, when the feeder link is available, the access network device sends the first request to the mobility management network element. At this time, the service link between the access network device and the first UE is disconnected.

[0210] S603: The mobility management network element determines at least one first time information according to the first request, where the first time information corresponds to a first monitoring period.

[0211] Specifically, the mobility management network element determines, based on the received first indication information, the at least one first listening period, during which the first UE is within the coverage of a satellite, and the satellite and the access network equipment provided thereon support S&F. Preferably, the mobility management network element determines the at least one first listening period based not only on the received first indication information, but also on acquired second information, such as subscription information of the first UE, local configuration of the mobility management network element, policy information (e.g., maximum number of paging times), access network equipment capability information, etc.

[0212] The first monitoring period may be an unavailable period of the first UE and / or a monitoring period of the first UE. For a detailed explanation, please refer to S601 and will not be repeated here.

[0213] The mobility management network element can periodically update the next unavailable period and / or listening period of the first UE corresponding to the first listening period, and determine the S&F satellite that has an available service link with the first UE after the unavailable period of the first UE through the updated first listening period, or determine the S&F satellite that has an available service link with the first UE during the listening period of the first UE.

[0214] S604. In response to the first request, the mobility management network element sends a first response to the access network device to the first UE, where the first response includes at least one first time information, where the first time information corresponds to a first monitoring period.

[0215] In a possible implementation, the first response is an attach accept or tracking area update (TAU) accept message.

[0216] S605: The access network device sends the first response to the first UE.

[0217] When the service link between the access network device and the first UE is available, the first response is sent. At this time, the feeder link between the access network device and the mobility management network element may have been disconnected.

[0218] S606: Based on the at least one first time information, the mobility management network element and the first UE periodically maintain corresponding time information.

[0219] The mobility management network element can periodically update the next unavailable period and / or listening period of the first UE corresponding to the first listening period, and determine the S&F satellite that has an available service link with the first UE after the unavailable period of the first UE through the updated first listening period, or determine the S&F satellite that has an available service link with the first UE during the listening period of the first UE.

[0220] At the same time, the first UE also periodically maintains its next unavailable period and / or monitoring period according to the received first indication information, and decides whether to monitor the satellite according to the unavailable period and / or monitoring period.

[0221] S607: The mobility management network element receives downlink data corresponding to the first UE from the core network, and determines the first satellite and the second indication information.

[0222] Specifically, after receiving downlink data corresponding to the first UE, the mobility management network element determines, based on the first UE's next unavailable period and / or monitoring period and preset ephemeris information or satellite coverage information, a first satellite to be monitored by the first UE. The first satellite supports S&F operations and can cache the downlink data. Optionally, the mobility management network element determines the first satellite to be the S&F satellite that earliest covers the first UE.

[0223] The mobility management network element further determines second indication information according to the next unavailable period and / or monitoring period of the first UE, where the second indication information indicates time information when the first satellite pages the first UE.

[0224] In an implementable manner, the time information for paging the first UE may be confirmed by start time information, end time information or duration information. Optionally, multiple pieces of information may be used to confirm the unavailable period of the first UE.

[0225] In another possible implementation, the time information for paging the first UE can be represented by timing information, and the timing information is used to indicate that the first satellite pages the first UE within a first time period after reaching the TA / TAI list covering the first UE. The timing information can correspond to the start or setting of a timer.

[0226] In another possible implementation, the time information indicating paging of the first UE may be the unavailable period of the first UE. By indicating the unavailable period of the first UE to the first satellite, the first satellite performs paging outside the unavailable period of the first UE after covering the TA / TAI list where the first UE is located.

[0227] S608: The mobility management network element sends the downlink data and the second indication information to the first satellite.

[0228] Optionally, the downlink data is carried by a paging request.

[0229] S609: The first UE monitors according to the first time information and receives paging from the first satellite.

[0230] According to the second indication information, the first satellite pages the first UE.

[0231] The first UE may monitor the satellite based on the first time information. In one achievable manner, the first UE may start a timer based on the first time information, determine that the satellite is an S&F satellite based on a broadcast message from the satellite, and monitor the satellite before the timer times out.

[0232] The first UE receives a paging message from an access network device set up on a first satellite. Specifically, a feeder link between the first satellite and the mobility management network element is unavailable, and a service link between the first satellite and the first UE is available.

[0233] S610: The first UE receives downlink data buffered by the first satellite.

[0234] S611: The first UE stops monitoring the first satellite.

[0235] Specifically, after the first UE completes receiving the downlink data from the first satellite, it stops monitoring the first satellite during the remaining coverage time of the first satellite.

[0236] In one possible implementation, a first UE receives indication information from a first satellite, where the indication information is used to indicate that downlink data transmission of the first UE is complete or to instruct the first UE to stop monitoring; the first UE stops monitoring the first satellite according to the indication information. Optionally, the indication information may be carried in a Radio Resource Control (RRC) connection release message. The first satellite determines, based on stored first data, that downlink data sent to the first UE has been sent, and because a feeder link between the first satellite and a core network is disconnected and new data from the first UE to the core network cannot be received, the first satellite determines that the first UE can stop monitoring and sends the indication information.

[0237] In another possible implementation, the first UE determines that the first satellite has completed downlink data transmission and stops monitoring the first satellite. Specifically, if no new downlink data is received from the first satellite within a first time period of receiving downlink data from the first satellite, the first UE determines that the first satellite has completed downlink data transmission and stops monitoring the first satellite. Preferably, the first UE stops monitoring the first satellite after establishing a single connection with the first satellite.

[0238] Through the method in this embodiment, the first UE can negotiate with the core network for the monitoring period of the S&F satellite (through the unavailable period and / or the expected monitoring period of the first UE), thereby reducing the number of monitored satellites and achieving energy saving. Furthermore, by allowing the first UE to no longer monitor paging during the remaining coverage time of the satellite after determining that the satellite has completed downlink data transmission, the time for the first UE to monitor paging when the service link is available can be further reduced, thereby improving energy saving. In addition, since the MME also regularly updates the next unavailable period and / or monitoring period of the first UE, paging indication information can be generated and sent to the satellite, so that the satellite can page the first UE in a more precise time period, which also saves the satellite's energy consumption and brings higher energy efficiency to the entire paging system.

[0239] In addition, based on its own power-saving needs, the first UE expands the reported unavailable period so that the period covered by some satellites is also included in the reported unavailable period, thereby further reducing the number and time of monitored satellites, especially reducing the time for monitoring paging when the service link is available, thereby improving energy saving effects.

[0240] The above description primarily describes the solutions provided by the embodiments of the present application from the perspective of interaction between various devices. Accordingly, the embodiments of the present application also provide a communication device for implementing the various methods described above. The communication device may be the mobility management network element, first access network device, or first terminal device described in the method embodiments described above, or a device comprising the mobility management network element, first access network device, or first terminal device, or a component usable for the mobility management network element, first access network device, or first terminal device. It will be understood that, to implement the aforementioned functions, the communication device includes hardware structures and / or software modules corresponding to the respective functions. Those skilled in the art will readily appreciate that, in conjunction with the various exemplary units and algorithm steps described in the embodiments disclosed herein, the present application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0241] In the embodiment of the present application, the communication device can be divided into functional modules according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be understood that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0242] Figure 7 shows a schematic diagram of the structure of a communication device 700. The communication device 700 includes a processing module 701 and a transceiver module 702. Optionally, the communication device 700 may also include a storage module 703. The transceiver module 702, also known as a transceiver unit, is used to implement transceiver functions and may be, for example, a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0243] Taking the communication device 700 as the first terminal device in the above embodiment as an example, in a possible implementation:

[0244] Processing module 701 is configured to determine first information, where the first information is used to determine monitoring information. Exemplarily, the first information is requested monitoring information, such as requested monitoring mode information, requested monitoring time information, and requested monitoring satellite information. Alternatively, the first information corresponds to a requested monitoring period, which may be an unavailable period of the first UE and / or a monitoring period of the first UE. Processing module 701 is configured to determine the first information based on at least one of a power saving requirement, a communication requirement, preset ephemeris information or satellite coverage information, and whether broadcast information has been received.

[0245] The transceiver module 702 is configured to send first information to the first access network device; optionally, the transceiver module 702 is further configured to send a first request message, wherein the first request message includes the first information. The transceiver module 702 is configured to receive monitoring information from the first access network device; optionally, the transceiver module 702 is configured to receive a first response message, wherein the first response message includes the monitoring information.

[0246] In one possible implementation, processing module 701 is configured to determine a monitored satellite based on the monitoring information. Exemplarily, processing module 701 monitors a satellite based on the monitoring information and preset ephemeris information or satellite coverage information. Furthermore, processing module 701 is configured to determine that a satellite is under the coverage of an S&F satellite based on broadcast information received by transceiver module 702, and then determine a monitored satellite based on the satellite's identification information and the monitoring information. Processing module 701 is also configured to determine not to monitor a satellite based on the monitoring information.

[0247] The transceiver module 702 is configured to receive broadcast information from a satellite. The broadcast information includes identification information indicating the satellite or an access network device deployed on the satellite. Furthermore, the broadcast information also includes indication information indicating whether the satellite supports S&F operations.

[0248] In one possible implementation, the transceiver module 702 is further configured to receive a paging message from the first satellite; the paging message is used to page the communication device 700. Furthermore, the paging message may include fifth indication information, which instructs the communication device 700 to receive downlink data buffered on the first satellite. The processing module 701 is configured to enable the communication device 700 to establish an RRC connection with the first satellite. The transceiver module 702 is further configured to receive downlink data from the first satellite.

[0249] In a possible implementation, the transceiver module 702 is further configured to send uplink data to the first satellite.

[0250] In one possible implementation, the transceiver module 702 is further configured to receive third indication information from the first satellite, the third indication information indicating that monitoring should be stopped or that data transmission has been completed. Optionally, the transceiver module 702 is further configured to receive a connection release message carrying the third indication information. The processing module 701 is further configured to determine to stop monitoring based on the third indication information.

[0251] In a possible implementation, the processing module 701 is further configured to determine that the downlink data of the first satellite has been sent completely, and to determine to stop monitoring.

[0252] Taking the communication device 700 as the mobility management network element in the above embodiment as an example, in a possible implementation manner:

[0253] The transceiver module 702 is configured to receive first information used to determine monitoring information. Optionally, the transceiver module 702 is further configured to receive a first request message, the first request message including the first information. After the processing module 701 determines the monitoring information, the transceiver module 702 is further configured to send the monitoring information to the first access network device. Optionally, the transceiver module 702 is configured to send a first response message to the first access network device, the first response message including the monitoring information.

[0254] In a possible implementation, the transceiver module 702 is used to receive a first notification message, where the first notification message is used to indicate receiving downlink data of the first terminal device.

[0255] In one possible implementation, the processing module 701 determines that the downlink data can be cached on the first satellite, including at least one of the following: determining that the first satellite supports a first function, where the first function includes a store and forward function; or determining that the downlink data supports transmission through a store and forward operation.

[0256] In one possible implementation, the processing module 701 determines that the downlink data supports transmission through a store and forward operation, including: determining that the downlink data supports transmission through a store and forward operation based on one or more of the following: the subscription information of the first terminal device, the latency requirement of the downlink data, or the context of the first terminal device.

[0257] In a possible implementation, the transceiver module 702 is further configured to receive a first request message from the first satellite, where the first request message is used to request establishment of a data transmission channel between the communication device 700 and the first satellite.

[0258] In one possible implementation, the processing module 701 is further configured to determine whether the first terminal device is within the coverage area corresponding to the first satellite based on the satellite coverage availability information corresponding to the first satellite and the location information of the first terminal device; wherein the satellite coverage information of the first satellite includes a mapping relationship between the coverage area corresponding to the first satellite and time. If the first terminal device is within the coverage area, the processing module 701 determines that the communication connection between the first satellite and the first terminal device is available; or if the first terminal device is not within the coverage area, the processing module 701 determines that the communication connection between the first satellite and the first terminal device is unavailable.

[0259] In one possible implementation, the processing module 701 determines the first satellite (or first access network device) with which communication is required. When the monitoring information is the S&F satellite monitoring list of the first terminal device, the processing module 701 is further configured to select the first satellite in the list according to the list. The first satellite may be the satellite in the list that covers the first terminal device the earliest, or the first satellite that covers the first terminal device the longest in the list. The mobility management network element may determine the first satellite based on the amount of downlink data, communication requirements, power saving requirements of the first terminal device, satellite capability information, and the like. When the monitoring information is the unavailable period of the first terminal device or the monitoring period of the first terminal device, the processing module 701 is further configured to determine the first satellite based on the monitoring information and at least one of the ephemeris information, satellite coverage information, and location information of the first terminal device. The first satellite supports S&F operations.

[0260] In a possible implementation, the transceiver module 702 is further configured to, after acquiring the downlink data of the first terminal device, send the downlink data to the first satellite through an available feeder link.

[0261] In one possible implementation, when the processing module 701 determines that the service link between the first satellite and the first terminal device located on the satellite is unavailable and the downlink data can be cached on the first satellite, the transceiver module 702 is further used to send the downlink data to the first satellite; optionally, it is also used to send first indication information, where the first indication information is used to indicate that the downlink data is cached to the first satellite; optionally, it is also used to send second indication information, where the second indication information is used to indicate a paging period.

[0262] Taking the communication device 700 as the first access network device in the above embodiment as an example, in a possible implementation manner:

[0263] The transceiver module 702 is used to receive first information from the first terminal device, and the first information is used to determine the monitoring information; optionally, the transceiver module 702 is also used to receive a first request message, and the first request message includes the first information. The transceiver module 702 is also used to send the first information to the mobility management network element; optionally, the transceiver module 702 is also used to send a first request message, and the first request message includes the first information. The transceiver module 702 is used to receive the monitoring information from the mobility management network element; optionally, the transceiver module 702 is used to receive a first response message, and the first response message includes the monitoring information. The transceiver module 702 is also used to send the monitoring information to the first terminal device; optionally, the transceiver module 702 is used to receive a first response message, and the first response message includes the monitoring information.

[0264] In one possible implementation, the transceiver module 702 is configured to receive a first paging message from a mobility management network element; wherein the first paging message is used to request paging of the first terminal device. Before the communication device 700 pages the first terminal device, the transceiver module 702 is further configured to send a first request message to the mobility management network element, wherein the first request message is used to request the mobility management network element to establish a data transmission channel with the communication device 700; wherein the communication connection between the first access network device located on the satellite and the first terminal device is unavailable. The transceiver module 702 is further configured to receive and cache downlink data from the mobility management network element. The transceiver module 702 is further configured to receive first indication information from the mobility management network element, wherein the first indication information is used to instruct to cache downlink data to the first satellite; further, the transceiver module 702 is further configured to receive second indication information from the mobility management network element, wherein the second indication information is used to indicate a paging period.

[0265] In one possible implementation, when the transceiver module 702 receives and buffers downlink data from the mobility management network element, the transceiver module 702 is further configured to send a second paging message to the first terminal device; the second paging message is used to page the first terminal device. The transceiver module 702 is further configured to receive an RRC connection request message from the first terminal device. The transceiver module 702 is further configured to send an RRC connection establishment message to the first terminal device. The transceiver module 702 is further configured to receive an RRC connection establishment completion message from the first terminal device. The transceiver module 702 is further configured to send downlink data to the first terminal device.

[0266] In a possible implementation, the transceiver module 702 is further configured to receive and buffer uplink data from the first terminal device.

[0267] In one possible implementation, processing module 701 is further configured to determine whether the cached downlink data has been completely sent. Transceiver module 702 is further configured to, if processing module 701 determines that the cached downlink data has been completely sent, send third indication information to the first terminal device, where the third indication information indicates to stop monitoring or indicates that the data transmission has been completely sent. Optionally, transceiver module 702 is further configured to send a connection release message, where the connection release message carries the third indication information.

[0268] Among them, all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0269] Alternatively, the modules in FIG7 may also be referred to as units. For example, the processing module may be referred to as a processing unit, and the transceiver module may be referred to as a transceiver unit. In addition, in the communication device shown in FIG7 , the names of the various units may not be those shown in the figure. For example, the transceiver module may also be referred to as a communication module or a communication unit.

[0270] If the various units in Figure 7 are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The storage medium for storing computer software products includes: various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0271] In the embodiment of the present application, the communication device 700 is presented in the form of various functional modules divided in an integrated manner. The "module" here can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions.

[0272] In a simple embodiment, those skilled in the art may appreciate that the communication device 700 may take the form of the communication device shown in FIG. 8 .

[0273] As shown in Figure 8, the communication device 800 includes one or more processors 801, a communication line 802, and at least one communication interface (Figure 8 is only an example of including a communication interface 804 and a processor 801 for illustration), and may optionally also include a memory 803.

[0274] The processor 801 may be a general-purpose central processing unit (CPU), a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of the program of the present application.

[0275] The communication line 802 may include a path for connecting different components.

[0276] The communication interface 804 may be a transceiver module for communicating with other devices or communication networks, such as Ethernet, RAN, terminals, and wireless local area networks (WLANs). For example, the transceiver module may be a device such as a transceiver or a transceiver. Alternatively, the communication interface 804 may be a transceiver circuit or input / output interface within the processor 801, for implementing signal input and output to the processor.

[0277] The memory 803 may be a device having a storage function. For example, it may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via a communication line 802. The memory may also be integrated with the processor.

[0278] The memory 803 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 801. The processor 801 is used to execute the computer-executable instructions stored in the memory 803, thereby implementing the communication method provided in the embodiment of the present application.

[0279] Alternatively, optionally, in an embodiment of the present application, the processor 801 may also perform processing-related functions in the communication method provided in the following embodiments of the present application, and the communication interface 804 is responsible for communicating with other devices or communication networks, which is not specifically limited in the embodiments of the present application.

[0280] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0281] In a specific implementation, as an embodiment, the processor 801 may include one or more CPUs, such as CPU0 and CPU1 in FIG8 .

[0282] In a specific implementation, as an embodiment, the communication device 800 may include multiple processors, such as the processor 801 and the processor 807 in FIG8 . Each of these processors may be a single-core processor or a multi-core processor. The processors herein may include, but are not limited to, at least one of the following: a CPU, a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, and other types of computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0283] In a specific implementation, as an embodiment, the communication device 800 may further include an output device 805 and an input device 806. The output device 805 communicates with the processor 801 and can display information in a variety of ways. For example, the output device 805 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 806 communicates with the processor 801 and can receive user input in a variety of ways. For example, the input device 806 can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0284] The communication device 800 described above may sometimes also be referred to as a communication device, which may be a general-purpose device or a dedicated device. For example, the communication device 800 may be the mobility management network element, the first access network device, the first terminal device, or a device having a similar structure as shown in FIG8 . The embodiments of the present application do not limit the type of the communication device 800.

[0285] In addition, the composition structure shown in Figure 8 does not constitute a limitation on the communication device. In addition to the components shown in Figure 8, the communication device 800 may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0286] Optionally, the functions / implementation processes of the transceiver module 702 and the processing module 701 in FIG7 may be implemented by the processor 801 in the communication device 800 shown in FIG8 calling computer-executable instructions stored in the memory 803. Alternatively, the functions / implementation processes of the processing module 701 in FIG7 may be implemented by the processor 801 in the communication device 800 shown in FIG8 calling computer-executable instructions stored in the memory 803, and the functions / implementation processes of the transceiver module 702 in FIG7 may be implemented by the communication interface 804 in the communication device 800 shown in FIG8.

[0287] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of the two. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in a memory, and a processor can be used to execute the program instructions and implement the above method flow. The processor can be built into an SoC or ASIC, or it can be an independent semiconductor chip. In addition to the core used to execute software instructions to perform calculations or processing within the processor, it can further include necessary hardware accelerators, such as FPGAs, programmable logic devices (PLDs), or logic circuits that implement dedicated logic operations.

[0288] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a DSP chip, an MCU, an artificial intelligence processor, an ASIC, a SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator or a non-integrated discrete device, which can run the necessary software or not rely on the software to execute the above method flow.

[0289] Optionally, an embodiment of the present application further provides a communication device (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the method in any of the above method embodiments. In one possible design, the communication device also includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the method in any of the above method embodiments. Of course, the memory may not be in the communication device. When the communication device is a chip system, it may be composed of a chip, or it may include a chip and other discrete devices, which is not specifically limited in the embodiment of the present application.

[0290] Optionally, an embodiment of the present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is run on a communication device, the communication device can execute the method described in any of the above method embodiments or any of its implementation methods.

[0291] Optionally, an embodiment of the present application further provides a communication system, which includes the network device described in the above method embodiment and the terminal device described in the above method embodiment.

[0292] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more media integrated therein. The available media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, solid state drives (SSDs)).

[0293] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0294] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A communication method, characterized in that: The method comprises: Sending a first request through a first service link, where the first request includes first indication information, where the first indication information is used to determine monitoring information; receiving a first response through the first service link, the first response including a first identifier or first time information, the first identifier corresponding to a first satellite to be monitored, and the first time information corresponding to a first monitoring period; At least one satellite is monitored according to the first identifier or the first time information, wherein the at least one satellite supports a store and forwarding (S&F) operation.

2. The communication method according to claim 1, wherein: The first response includes the first identifier, and the first indication information is used to determine monitoring information, including: The first indication information is used to determine at least one satellite that needs to be monitored; The monitoring of at least one satellite according to the first identifier or the first time information includes: The first satellite is monitored according to the first identifier and preset ephemeris information or satellite coverage information.

3. The communication method according to claim 2, wherein: The first indication information includes first auxiliary information, and the first indication information is used to indicate that the at least one satellite that needs to be monitored is determined according to the first auxiliary information.

4. The communication method according to claim 2, wherein: The first indication information includes at least one satellite identification information, and the at least one satellite identification information includes the first identification.

5. The communication method according to claim 1, wherein: The first response includes the first time information, and the method further includes: Determining second time information according to preset ephemeris information or satellite coverage information, where the second time information indicates that a service link with the satellite is unavailable; The first indication information includes the second time information; the first time information is determined according to the second time information; The monitoring of at least one satellite according to the first identifier or the first time information includes: A paging message is received from the at least one satellite according to the first time information. The communication method according to claim 5 , wherein: The second time information further includes period information, where the period information corresponds to a period during which the service link with the satellite is unavailable.

7. The communication method according to claim 5 or 6, characterized in that: The first indication information also includes third time information, and the third time information indicates an expected monitoring period; the first time information is determined based on the second time information, including: the first time information is determined based on the third time information and the second time information.

8. The communication method according to any one of claims 1 to 7, characterized in that: The method further comprises: Establishing a second service link with the first satellite; receiving first data from the first satellite; After receiving the first data, if the second service link is available, stop monitoring the first satellite.

9. The communication method according to any one of claims 1 to 7, characterized in that: The method further comprises: receiving second instruction information from the first satellite, where the second instruction information is used to instruct to stop monitoring; Stop monitoring the first satellite according to the second instruction information.

10. The communication method according to claims 1 to 9, characterized in that: The method further comprises: The first request is an attach request or a tracking area update (TAU) request message; The first response is an attach accept or tracking area update accept message.

11. A communication method, characterized in that: The method comprises: receiving a first request from a first terminal device, where the first request includes first information, and the first indication information is used to determine monitoring information; sending a first response according to the first information, the first response including a first identifier or first time information, the first identifier corresponding to a first satellite to be monitored, the first time information corresponding to a first monitoring period, and a service link of the first terminal device being available during the first monitoring period; receiving first data from the first terminal device; When a service link between the first terminal device and the first satellite is unavailable, sending the first data to the first satellite, where the first satellite supports a store and forwarding (S&F) operation on the first data; The first terminal accesses the network via a satellite.

12. The communication method according to claim 11, wherein: The first response includes a first identifier, and the first indication information is used to determine monitoring information, including: The first indication information is used to determine at least one satellite that needs to be monitored; Determining the first response according to the first information further includes: The first identifier is determined based on the position of the first terminal device, the preset ephemeris information or satellite coverage information and the first information.

13. The communication method according to claim 12, wherein: The first indication information includes first auxiliary information, and the first indication information is used to indicate the at least one satellite that needs to be monitored based on the first auxiliary information.

14. The communication method according to claim 12, wherein: The first indication information includes at least one satellite identification information, and the first identification is also determined according to the at least one satellite identification information.

15. The communication method according to claim 11, wherein: The first information includes the second time information, the second time information corresponds to unavailability of a service link between the first terminal device and the satellite, and determining the first response based on the first information includes: Determining the first time information according to the second time information, the position of the first terminal device and preset ephemeris information or satellite coverage information; The sending the first data to the first satellite includes: determining the first satellite according to the second time information; The first data is sent to the first satellite.

16. The communication method according to claim 15, characterized in that: The second time information further includes period information, where the period information corresponds to a period during which the service link with the satellite is unavailable.

17. The communication method according to claim 15 or 16, characterized in that: The first indication information also includes third time information, and the third time information is used to indicate the desired monitoring period of the first terminal device; the first time information is determined based on the second time information, including: the first time information is determined based on the third time information and the second time information.

18. The communication method according to claims 15 to 17, characterized in that: The first time information and the second time information are periodically maintained.

19. The communication method according to claims 11 to 18, characterized in that: The sending the first data to the first satellite includes: The paging request is sent to the first satellite, where the paging request includes the first data and paging time information, where the paging time information is used to page the first terminal device, and the paging time information is determined based on the first identifier or the first time information.

20. A communication method, characterized in that: The method comprises: receiving first data from a core network element through a feeder link, where the first data corresponds to a first terminal device; When the feeder link is unavailable and the service link with the first terminal device is available, the first data is sent to the first terminal device.

21. The method according to claim 20, characterized in that The receiving the first data from the core network element through the feeder link includes: receiving a paging request from a core network element through a feeder link, where the paging request includes the first data; The paging request further includes first paging time information, where the first paging time information indicates that the first terminal device is to be paged in a first paging cycle.

22. The method according to claim 21, characterized in that The first paging time information includes a first start time, and the first start time is used to indicate the start of paging the first terminal device.

23. The method according to claim 22, characterized in that The first paging time information also includes first time information, and the first time information corresponds to the service link between the first terminal device being unavailable.

24. The method according to claim 20, characterized in that The method further comprises: When the first data is sent, first indication information is sent to the first terminal device, and the first indication information indicates to stop monitoring.

25. The method according to claims 20 to 24, characterized in that The method further comprises: Broadcast information is sent, where the broadcast information carries indication information that a store and forward operation is supported.

26. A communication device, characterized in that: The communication device comprises a module or unit for executing the method according to any one of claims 1-10, 11-19 or 20-25.

27. A communication device, characterized in that: The communication device includes: a processor; the processor is configured to execute a computer program or instruction stored in a memory, so that the communication device performs the method according to any one of claims 1-10, 11-19, or 20-25.

28. A chip system, characterized in that: include: processor and interface circuits; The interface circuit is used to receive computer execution instructions and transmit them to the processor; The processor is configured to execute the computer-executable instructions so as to cause the communication device to perform the method according to any one of claims 1-10, 11-19, or 20-25.

29. A computer-readable storage medium, characterized in that A computer program or instruction is stored thereon, which, when executed by a computer, causes the computer to perform the method according to any one of claims 1 to 10, 11 to 19, or 20 to 25.

30. A communication system, characterized in that: The communication system includes a mobility management network element and a first access network device; wherein the mobility management network element is used to execute the method according to any one of claims 11 to 19, and the first access network device is used to execute the method according to any one of claims 20 to 25.

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