Method and apparatus for wireless communication

Abstract

The present application provides a method and apparatus for wireless communication, which facilitate reducing the power consumption of terminal devices in a scenario where network coverage is discontinuous. The method comprises: a terminal device determines first time information; and on the basis of the first time information, the terminal device executes a transition from a first state to a second state, wherein the first time information is related to a first time period and / or a second time period, the first time period is a time period from a current moment to a starting moment when the terminal device enters a no-network-coverage scenario, and the second time period is the duration of the no-network-coverage scenario.

Description

Method and apparatus for wireless communication Technical Field

[0001] The present application relates to the field of communication technology, and more particularly, to a method and apparatus for wireless communication. Background Art

[0002] With the increasing use of satellites in non-terrestrial networks (NTNs), end-user devices may find themselves without network coverage. Due to discontinuous network coverage, the operation of energy-efficient end-user devices and network-side configuration are both worthy research issues. For example, in NTN systems based on the Internet of Things (IoT), determining when IoT end-user devices release their radio resource control (RRC) connections or wake up is a crucial issue.

[0003] Summary of the Invention

[0004] The present application provides a method and apparatus for wireless communication. The following describes various aspects of the embodiments of the present application.

[0005] In a first aspect, a method for wireless communication is provided, comprising: a terminal device determining first time information; based on the first time information, the terminal device performing a transition from a first state to a second state; wherein the first time information is related to a first time period and / or a second time period, the first time period being a time period from a current moment to a starting moment when the terminal device enters a state without network coverage, and the second time period being a duration period of the state without network coverage.

[0006] According to a second aspect, a method for wireless communication is provided, comprising: a network device determines first time information; based on the first time information, the network device instructs a terminal device to perform a transition from a first state to a second state; wherein the first time information is related to a first time period and / or a second time period, the first time period being a time period from a current moment to a starting moment when the terminal device enters a state without network coverage, and the second time period being a duration period of the state without network coverage.

[0007] According to a third aspect, a device for wireless communication is provided, which is a terminal device, and includes: a determination unit for determining first time information; a first execution unit for executing a transition from a first state to a second state based on the first time information; wherein the first time information is related to a first time period and / or a second time period, the first time period is a time period from the current moment to the starting moment when the terminal device enters a state without network coverage, and the second time period is a duration period of the state without network coverage.

[0008] In a fourth aspect, a device for wireless communication is provided, which is a network device, and includes: a determination unit for determining first time information; an indication unit for instructing a terminal device to perform a transition from a first state to a second state based on the first time information; wherein the first time information is related to a first time period and / or a second time period, the first time period is a time period from the current moment to the starting moment when the terminal device enters a state without network coverage, and the second time period is a duration period of the state without network coverage.

[0009] In a fifth aspect, a communication device is provided, comprising a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method described in the first aspect or the second aspect.

[0010] In a sixth aspect, a device is provided, comprising a processor for calling a program from a memory to execute the method as described in the first aspect or the second aspect.

[0011] In a seventh aspect, a chip is provided, comprising a processor for calling a program from a memory so that a device equipped with the chip executes the method described in the first aspect or the second aspect.

[0012] In an eighth aspect, a computer-readable storage medium is provided, on which a program is stored, wherein the program enables a computer to execute the method as described in the first aspect or the second aspect.

[0013] In a ninth aspect, a computer program product is provided, comprising a program, wherein the program enables a computer to execute the method as described in the first aspect or the second aspect.

[0014] In a tenth aspect, a computer program is provided, which enables a computer to execute the method as described in the first aspect or the second aspect.

[0015] In an embodiment of the present application, a terminal device can determine first time information and perform a transition from a first state to a second state based on the first time information. The first time information includes a first time period from when the terminal device currently has network coverage to when it enters a state without network coverage, and a second time period during which the lack of network coverage persists. Thus, the terminal device can predict the time information of lack of network coverage and perform a state transition when network coverage is discontinuous, thereby further saving power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a wireless communication system used in an embodiment of the present application.

[0017] FIG2 is an NTN system used in an embodiment of the present application.

[0018] FIG3 is another NTN system applied in an embodiment of the present application.

[0019] FIG4 is a schematic diagram of a possible scenario in which a terminal device is in discontinuous coverage.

[0020] Figure 5 is a schematic diagram of an energy-saving configuration introduced by the Internet of Things.

[0021] FIG6 is a schematic diagram of another energy-saving configuration introduced by the Internet of Things.

[0022] FIG7 is a flow chart of a method for wireless communication provided in an embodiment of the present application.

[0023] FIG8 is a flow chart of a possible implementation of the method shown in FIG7

[0024] FIG9 is a flow chart of another method for wireless communication provided in an embodiment of the present application.

[0025] FIG10 is a schematic diagram of a possible configuration manner of the first configuration parameter.

[0026] FIG11 is a schematic diagram of another possible configuration manner of the first configuration parameter.

[0027] FIG12 is a schematic diagram of another possible configuration manner of the first configuration parameter.

[0028] FIG13 is a schematic diagram of another possible configuration manner of the first configuration parameter.

[0029] FIG14 is a flowchart of a possible implementation of the method shown in FIG9 .

[0030] FIG15 is a flowchart of another possible implementation of the method shown in FIG9 .

[0031] FIG16 is a schematic structural diagram of a device for wireless communication provided in an embodiment of the present application.

[0032] FIG17 is a schematic structural diagram of another apparatus for wireless communication provided in an embodiment of the present application.

[0033] FIG18 is a schematic structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. With respect to the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] The embodiments of the present application can be applied to various communication systems. For example, the embodiments of the present application can be applied to global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, advanced long term evolution (LTE-A) system, new radio (NR) system, evolution system of NR system, LTE-based access to unlicensed spectrum (LTE-U) system on unlicensed spectrum, NR-based access to unlicensed spectrum (NR-U) system on unlicensed spectrum, NTN system, universal mobile telecommunication system (UMTS), wireless local area networks (WLAN), wireless fidelity (WiFi), and fifth generation communication (5th-generation, 5G) system. The embodiments of the present application can also be applied to other communication systems, such as future communication systems. The future communication system may be, for example, a sixth-generation (6G) mobile communication system or a satellite communication system.

[0036] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can not only support traditional cellular communications, but also support one or more other types of communications. For example, a communication system can support one or more of the following communications: device to device (D2D) communication, machine to machine (M2M) communication, machine type communication (MTC), enhanced machine type communication (eMTC), vehicle to vehicle (V2V) communication, and vehicle to everything (V2X) communication, etc. The embodiments of the present application can also be applied to communication systems that support the above-mentioned communication methods.

[0037] The communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0038] The communication system in the embodiments of the present application can be applied to unlicensed spectrum. The unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in the embodiments of the present application can also be applied to licensed spectrum. The licensed spectrum can also be considered a dedicated spectrum.

[0039] The embodiments of the present application can be applied to an NTN system. As an example, the NTN system can be a 4G-based NTN system, an NR-based NTN system, an IoT-based NTN system, or an NB-IoT-based NTN system.

[0040] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of the present application may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0041] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a next-generation communication system (e.g., a NR system), or a terminal device in a future-evolved public land mobile network (PLMN) network.

[0042] In some embodiments, a terminal device may be a device that provides voice and / or data connectivity to a user. For example, the terminal device may be a handheld device, an in-vehicle device, etc. with wireless connection capabilities. As some specific examples, the terminal device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

[0043] In some embodiments, the terminal device can be deployed on land. For example, the terminal device can be deployed indoors or outdoors. In some embodiments, the terminal device can be deployed on the water, such as on a ship. In some embodiments, the terminal device can be deployed in the air, such as on an airplane, a balloon, or a satellite.

[0044] In addition to the terminal device, the communication system may also include one or more network devices. The network device in the embodiment of the present application may be a device for communicating with the terminal device, and the network device may also be referred to as an access network device or a radio access network device. The network device may be, for example, a base station. The network device in the embodiment of the present application may refer to a radio access network (RAN) node (or device) that connects the terminal device to a wireless network. The base station can broadly cover various names as follows, or be replaced with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (transmitting and receiving point, TRP], transmitting point (transmitting point, TP]), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (distributed unit, DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, a modem or a chip used to be set in the aforementioned equipment or device. The base station can also be a mobile switching center and a device that performs the base station function in D2D, V2X, and M2M communications, a network side device in a 6G network, a device that performs the base station function in a future communication system, etc. The base station can support networks with the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network equipment.

[0045] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

[0046] In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device may include a CU and a DU. The gNB may also include an AAU.

[0047] By way of example and not limitation, in embodiments of the present application, a network device may be mobile, for example, a mobile device. In some embodiments of the present application, the network device may be a satellite or balloon station. In some embodiments of the present application, the network device may also be a base station located on land, water, or the like.

[0048] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0049] In a communication system, a PLMN can be composed of a group of base stations, a RAN, and a core network (CN). The base stations are responsible for wireless communication with terminal devices, the RAN is responsible for transmitting signals to the core network, and the core network is responsible for processing and forwarding communication data.

[0050] In some embodiments, the order of PLMN selection is generally: registered public land mobile network (RPLMN) → home public land mobile network (HPLMN) → user controlled public land mobile network (UPLMN) → operator controlled public land mobile network (OPLMN). RPLMN is the PLMN registered by the terminal device before the last shutdown or disconnection from the network, and will be temporarily saved on the universal subscriber identity module (USIM) card. The operator corresponding to the HPLMN may have different number segments. Among them, HPLMN is the PLMN corresponding to the international mobile subscriber identity (IMSI) of the user's USIM. UPLMN is the user-controlled PLMN list. The PLMN list and the corresponding access technology (ACT) are stored in two dedicated files of the USIM card / subscriber identity module (SIM) card. Terminal devices must be able to identify and read these files on the USIM / SIM card to perform PLMN selection. Otherwise, the operation will be inoperable. When a carrier burns a SIM card, it writes the PLMNs with which it has a roaming agreement as OPLMNs to the USIM card, suggesting network selection for that carrier's users. Forbidden PLMNs (FPLMNs) are typically determined when a terminal device attempts to access a specific PLMN and is denied. The terminal device adds the denied PLMN to its FPLMN list.

[0051] In NB-IoT, the non-access stratum (NAS) typically selects the highest-priority PLMN. The terminal device prioritizes searching for this designated PLMN. If the terminal device finds the designated PLMN cell, it immediately initiates a reside / register attempt. If the terminal device cannot find the designated PLMN, after searching all cells, it searches for the next-highest priority PLMN and attempts to reside / register there.

[0052] For example, Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application. As shown in Figure 1, the communication system 100 may include a network device 110, which may be a device that communicates with a terminal device 120 (or also referred to as a communication terminal or terminal). The network device 110 may provide communication coverage for a specific geographic area and may communicate with terminal devices located within the coverage area.

[0053] FIG1 exemplarily shows a network device and two terminal devices. In some embodiments of the present application, the communication system 100 may include multiple network devices and each network device may include another number of terminal devices within its coverage area, which is not limited.

[0054] For example, Figure 2 illustrates an architecture diagram of the aforementioned NTN system. NTN system 200 in Figure 2 utilizes satellite 210 as an aerial platform. As shown in Figure 2, the satellite radio access network includes satellite 210, service link 220, feeder link 230, terminal equipment 240, gateway (GW) 250, and network 260, including base stations and a core network.

[0055] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal device 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. The earth-based gateway 250 connects satellite 210 to a base station or core network, depending on the selected NTN architecture.

[0056] The NTN architecture shown in Figure 2 is a bent-pipe transponder architecture. In this architecture, a base station is located on Earth behind gateway 250, with satellite 210 acting as a relay. Satellite 210 operates as a relay, forwarding signals from feeder link 230 to service link 220, or vice versa. In other words, satellite 210 does not function as a base station; communications between terminal device 240 and base stations in network 260 must be relayed through satellite 210.

[0057] Figure 3 illustrates another NTN system architecture. As shown in Figure 3, satellite radio access network 300 includes satellite 310, service link 320, feeder link 330, terminal equipment 340, gateway 350, and network 360. Unlike Figure 2, satellite 310 is equipped with a base station 312, while network 360 behind gateway 350 only includes the core network. Since the base stations are deployed on the satellite, the PLMN now consists solely of the core network.

[0058] The NTN architecture shown in Figure 3 is a regenerative transponder architecture. In this architecture, satellite 310 carries base station 312, which can be directly connected to the Earth-based core network via a link. Satellite 310 functions as a base station, and terminal device 340 can communicate directly with satellite 310. Therefore, satellite 310 can be referred to as a network device.

[0059] The communication system of the architecture shown in Figures 2 and 3 may include multiple network devices, and each network device may include other number of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0060] In the embodiment of the present application, the communication system shown in Figures 1 to 3 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but the embodiment of the present application does not limit this.

[0061] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal device 120 having a communication function. The network device 110 and the terminal device 120 may be the specific devices described above and will not be described in detail here. The communication device may also include other devices in the communication system 100, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0062] For ease of understanding, some relevant technical knowledge involved in the embodiments of this application is first introduced. The following related technologies can be combined with the technical solutions of the embodiments of this application as optional solutions, and they all fall within the scope of protection of the embodiments of this application. The embodiments of this application include at least part of the following contents.

[0063] As communication technologies develop, communication systems (e.g., 5G) will integrate the market potential of satellite and terrestrial network infrastructure. For example, the 5G standard makes NTN, including satellite segments, part of the recognized 3rd Generation Partnership Project (3GPP) 5G connectivity infrastructure.

[0064] NTN refers to a network or network segment that utilizes radio frequency (RF) resources on satellite or unmanned aerial system (UAS) platforms. Taking satellites as an example, communications satellites are categorized by orbital altitude into low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), and high elliptical orbit (HEO). LEO is an Earth-centered orbit with an altitude of 2,000 kilometers or less, or with at least 11.25 cycles per day and an eccentricity of less than 0.25. Most man-made objects in outer space are located in LEO. LEO satellites orbit the Earth at high speed (mobility) but in predictable or deterministic orbits.

[0065] Satellites at different orbital altitudes have different orbital periods. For example, LEO typically has an altitude of 250-1500 kilometers and an orbital period of 90-120 minutes. MEO typically has an altitude of 5000-25000 kilometers and an orbital period of 3-15 hours. GEO has an altitude of approximately 35786 kilometers and an orbital period of 24 hours.

[0066] As shown in Figures 2 and 3, which used satellites as examples, typical scenarios for terminal devices accessing the NTN system involve either an NTN transparent payload or an NTN regenerative payload. The bent-pipe transponder architecture shown in Figure 2 corresponds to the NTN transparent payload, while the regenerative transponder architecture shown in Figure 3 corresponds to the NTN regenerative payload.

[0067] In an NTN system, communications equipment can infer the trajectory of the cell a satellite can serve based on its ephemeris and epoch time. The satellite ephemeris contains information such as the satellite's position and velocity at a specific epoch. The epoch time is the reference point for the satellite's orbital parameters. The ephemeris also includes parameters such as the satellite's semi-major axis, eccentricity, inclination, and the longitude of the ascending node.

[0068] In some embodiments, a terminal device can use satellite ephemeris and epoch time to calculate a satellite's orbit. For example, the terminal device can calculate the satellite's orbital parameters based on Kepler's laws. Furthermore, orbital parameters and time information can be used to predict the satellite's position at a certain point in the future. For another example, mathematical models can be used to calculate satellite parameters, taking into account the satellite's motion in orbit and the Earth's rotation.

[0069] As an example, for an elliptical orbit of a satellite, with a semi-major axis a, an eccentricity e, an inclination i, an ascending node longitude Ω, a perigee parameter ω, and a mean anomaly M, the mean anomaly corresponding to time t can be expressed as: M(t) = M0 + n*(t-t0);

[0070] Among them, M(t) is the mean anomaly of the satellite, M0 is the mean anomaly corresponding to epoch time t0, and n is the mean angular velocity of motion.

[0071] The eccentric anomaly angle E can be obtained by solving Kepler's equation: Ee*sin(E)=M(t).

[0072] The eccentric anomaly E can be converted to the true anomaly ν according to the following formula:

[0073] After determining the true anomaly, the position of the satellite in orbit can be calculated using the orbital parameters. In other words, the position of the satellite is expressed by the satellite's orbital equation. The distance r between the satellite and the center of the earth can be calculated using the following formula: r = a*(1-e 2 ) / (1+e*cos(v)).

[0074] Furthermore, the orbital parameters and true anomaly are used to calculate the position (x, y, z) of the satellite in the rectangular coordinate system: x = r*(cos(Ω)*cos(ω+v)-sin(Ω)*sin(ω+v)*cos(i)); y = r*(sin(Ω)*cos(ω+v)+cos(Ω)*sin(ω+v)*cos(i)); z = r*sin(i)*sin(ω+v).

[0075] In an NTN system, multiple satellites form a constellation to provide services to devices within an NTN cell. Satellites serving mobile Earth cells typically provide shorter service times than satellites serving fixed Earth cells. In mobile Earth cells, the duration of satellite coverage depends on the size of the satellite's footprint, which is related to its orbital altitude. For example, a LEO satellite's beam can reach up to 1,000 kilometers, with a maximum coverage time of approximately 130 seconds.

[0076] However, even during satellite constellation operation, ground-based terminal devices may still experience a lack of network coverage. That is, under the coverage of the NTN network, terminal devices may experience discontinuous network coverage. The following provides an example of a discontinuous coverage scenario.

[0077] In some embodiments, due to the limited number of satellites in orbit, network coverage may be discontinuous for a terminal device on the ground. For example, in an IoT-based Earth mobile cell, a terminal device may not be served by any satellite at a given moment. In other words, the network coverage provided to the IoT device is discontinuous.

[0078] In some embodiments, even if a terminal device is within the geographic coverage area of ​​a satellite, the satellite's beam coverage may not include the terminal device. In this scenario, the terminal device may also be in an area of ​​discontinuous coverage. For ease of understanding, the following example uses a mobile cell as an example, combined with a discontinuous coverage scenario shown in Figure 4 for exemplary description.

[0079] In the NTN system shown in Figure 4 , terminal device 410 and terminal device 420 are both located within the geographic coverage area of ​​satellite 430. Terminal device 410 is located near position 401 of satellite 430 perpendicular to the ground, while terminal device 420 is located near position 402. As shown in Figure 4 , the center of the beam transmitted by satellite 430 at epoch time t corresponds to ground position 402, and satellite 430 can provide service to terminal device 420. However, because the beam center is not perpendicular to satellite 430's ground projection position 401, satellite 430 cannot provide service to terminal device 410, resulting in discontinuous coverage for terminal device 410.

[0080] The above article uses the IoT as an example to analyze the causes of discontinuous NTN coverage. Applications such as the IoT and MTC are experiencing exponential growth and are expected to play a key role in future networks and systems. In these systems, terminal devices transmit data infrequently and do not require constant communication with network devices. To conserve energy, the network can configure various energy-saving modes for terminal devices.

[0081] For example, NB-IoT can support three energy-saving modes: power saving mode (PSM), discontinuous reception (DRX) mode, and extended discontinuous reception (DRX) mode. In PSM mode, the terminal device does not need to receive paging to detect whether there is downlink service. Compared with DRX mode, the terminal device in eDRX mode will have a longer paging detection cycle.

[0082] Furthermore, NB-IoT uses PSM and eDRX modes to save power in terminal devices. For example, whether a terminal device uses PSM and eDRX depends on the terminal device's capabilities and network configuration. Regarding capabilities, the network will not configure capabilities that the terminal device does not support. Even if a terminal device supports a capability, the configuration may vary depending on the network.

[0083] The following describes the operation of power-saving mode using PSM mode as an example. A terminal device that supports PSM mode enters PSM after being idle for a period of time. In PSM, the terminal device's power amplifier (PA) stops operating. In other words, the terminal device's radio frequency (RF) also stops functioning. Furthermore, the terminal device's access stratum (AS) disables some related functions to reduce power consumption in the RF and signaling processing components, thereby achieving low power consumption.

[0084] On the other hand, since the RF part of the terminal device stops working, the terminal device cannot receive any paging or scheduling. For the network side, the terminal device is in an unreachable state at this time. In the unreachable state, neither data nor text messages can reach the terminal device. However, the terminal device is still marked as registered in the network. Therefore, when the terminal device is awakened from the PSM state (unreachable state), it does not need to re-establish the public data network (PDN) connection, but can send data directly.

[0085] In PSM mode, the terminal device's state transitions can be achieved using two timers: the T3324 timer and the T3412 timer. For ease of understanding, the following examples illustrate different energy-saving modes with reference to Figures 5 and 6. In Figures 5 and 6, the horizontal axis represents time, and the vertical axis represents energy consumption.

[0086] As shown in Figure 5, a terminal device can transmit data in the active state, which consumes more energy, while in the idle state, it primarily receives data, which consumes less energy. After a period of idle state without re-entering the active state, the terminal device directly enters the lower-energy PSM state. The duration of the terminal device's idle state is the duration of the T3324 timer.

[0087] Continuing with Figure 5, a complete Tracking Area Update (TAU) cycle is the sum of the IDLE and PSM times. The duration of a TAU cycle is defined as the duration of the T3412 timer. Therefore, T3412 is the TAU duration, while T3324 is the timer required to enter the PSM state from the IDLE state.

[0088] In certain specific access point networks (APNs), terminal devices can modify the T3412 and T3324 timers through standard instructions specified by the 3rd Generation Partnership Project (3GPP) protocol.

[0089] As an example, in NB-IoT, terminal devices can use attention (AT) commands (ATCommands) to communicate and configure the NB-IoT module. AT commands are sent from the terminal device or data terminal to the terminal adapter (terminal adapter) or data circuit terminal. The terminal device controls the functions of the mobile station by sending AT commands and interacts based on various network services. The terminal device can send the command to the narrowband (NB) module. The module can carry AT commands in reliable (CON) or unreliable (NON) messages sent to the NB-IoT platform.

[0090] As an example, a terminal device can modify timers T3412 and T3324 using the AT+CPSMS command. CPSMS stands for control plane support for mobile terminated services. The AT+CPSMS command can be used to set parameters related to the PSM. In NB-IoT communications, AT+CPSMS is an AT command used to control the PSM.

[0091] Figure 6 schematically illustrates the relevant parameters in eDRX mode. The minimum interval in traditional DRX mode is 2.56 seconds (DRX cycle), which is too frequent for IoT devices, where data transmission is infrequent. To further reduce the power consumption associated with monitoring paging, NB-IoT introduces enhanced discontinuous reception (eDRX) technology. Within each eDRX cycle, there is a paging time window (PTW). During the PTW, the terminal device monitors and responds to paging messages sent by the network.

[0092] It should be noted that a terminal device can only monitor the paging channel according to the DRX cycle during the PTW period to receive downlink services. Due to the short DRX cycle, the terminal can be considered active and always reachable during the PTW period. Outside the PTW period, the terminal is in a sleep state, does not monitor the paging channel, and cannot receive downlink services. Therefore, the PTW window period is a state of eDRX. Once the PTW window expires, the device enters a silent state and cannot receive paging until the next periodic PTW period.

[0093] As shown in Figure 6, the terminal device intermittently monitors paging according to the eDRX cycle in idle mode, reducing power consumption. Specifically, after a PTW, the terminal device enters a silent state and waits for the eDRX cycle to complete before re-entering the PTW to monitor paging. If a paging message falls outside the PTW, the terminal device cannot respond and must wait until the network-side cached paging message is sent again and falls within the PTW before it can successfully respond. This shows that the sleep time of terminal devices in eDRX mode is relatively long.

[0094] During the communication process, the network side (core network) can configure various energy-saving mode parameters for the terminal device. For example, the network side can configure eDRX related parameters for the terminal device through AMF or MME.

[0095] As an example, the terminal device can first negotiate with the MME to obtain the terminal device-specific eDRX, and then obtain the hyper-system frame number (H-SFN) of the paging message by calculating the paging hyper-frame (PH). Then, the terminal device can obtain the possible system frame number (SFN) area range where its paging message is located by calculating the paging time window (PTW). Among them, PTW is specific to the terminal device and can be determined by PH, the starting position (PTW_start) and the ending position (PTW_end) within the PH. Finally, the terminal device can obtain the subframe where the paging message is located through the paging frame (PF) and the paging occasion (PO).

[0096] At the same time, the core network can also configure an appropriate eDRX cycle for the terminal device. The position of the PH, PTW_start, and PTW_end are mainly determined by the eDRX cycle, PTW length, and the identity (ID) of the terminal device. For example, the PH, PTW_start, and PTW_end can be determined according to the following formula: H-SFN mod TeDRX,H = (UE_ID_H mod TeDRX,H);

[0097] The UE_ID_H is determined as follows: if the paging radio network temporary identifier (P-RNTI) is monitored on the physical downlink control channel (PDCCH) or the MTC physical downlink control channel (MTC PDCCH, MPDCCH), the ID is the most significant 10 bits of the hash function; if the P-RNTI is monitored on the narrowband physical downlink control channel (NPDCCH), the ID is the most significant 12 bits of the hash function.

[0098] TeDRX,H is the terminal device's eDRX cycle in a superframe. Typically, TeDRX,H = 1, 2, ..., 256 superframes. For NB-IoT, TeDRX,H = 2, ..., 1024 superframes. TeDRX,H is configured by higher layers. One superframe equals the duration of 1024 SFNs, or 10.24 seconds. Therefore, the eDRX cycle can range from 20.48 seconds to 2.9127 hours.

[0099] PTW_start represents the first radio frame of PH. PTW_start is the SFN that satisfies the following equation:

[0100] SFN=256*ieDRX, where ieDRX=floor(UE_ID_H / TeDRX,H)mod 4.

[0101] PTW_end is the last radio frame of PTW. PTW_end is the SFN that satisfies the following equation:

[0102] SFN = (PTW_start + L*100-1) mod 1024, where L is the paging time window length (seconds) configured by the upper layer.

[0103] The above describes various energy-saving modes and related parameters of the eDRX mode in conjunction with Figures 5 and 6. As can be seen from Figures 5 and 6, the energy consumption of the terminal device in the idle state and PSM state is low, thus achieving energy saving.

[0104] As mentioned above, discontinuous network coverage can occur under NTN coverage. When IoT and MTC are under NTN coverage, the window of no network coverage may misalign with the window when the terminal device is unreachable, affecting energy conservation and communication quality. Therefore, how IoT terminal devices operate under discontinuous coverage is a question worth studying.

[0105] Furthermore, as mentioned previously, the core network configures DRX, eDRX, and PSM configurations for terminal devices. However, when a terminal device is in an NTN, receiving signals from base stations via satellite is a process within the access network. The core network may not be aware of the access network's coverage and, therefore, will not proactively configure eDRX and PSM configurations for the terminal device that are suitable for communication scenarios with discontinuous satellite signal coverage. This is also an issue worthy of research.

[0106] For example, when a terminal device attempts to establish a connection with a satellite, the remaining satellite coverage time may be too short, making it impossible to complete the connection. For example, when a terminal device is about to lose network coverage, it may be in an awake or idle state, and the power consumption of the terminal device attempting to send data or receive paging calls may be wasted. Therefore, terminal devices in IoT or MTC applications need to consider scenarios with discontinuous coverage to better save power and ensure communication quality.

[0107] It should be noted that the above-mentioned problem that the energy-saving configuration of the Internet of Things may be affected by the discontinuous coverage of the NTN system is only an example. The embodiments of the present application can be applied to any type of scenario where the terminal device-related configuration is affected due to discontinuous network coverage.

[0108] Based on this, embodiments of the present application provide a method for wireless communication. Using this method, a terminal device can predict the first time it enters a state without network coverage, and then transition between different states based on this first time information to save power or successfully establish communication with a satellite. For ease of understanding, the method provided in embodiments of the present application is described in detail below with reference to FIG7 .

[0109] 7 , in step S710 , the terminal device determines first time information.

[0110] The terminal device is any type of terminal device described above and is not limited here.

[0111] In some embodiments, the terminal device is a device that communicates via a satellite in an NTN system. For example, when a base station is deployed on a satellite, the terminal device communicates directly with the base station on the satellite. For example, when a satellite acts as a relay, the terminal device communicates with terrestrial network equipment via the satellite.

[0112] As an example, a terminal device is currently located within the service area of ​​a first satellite in the NTN. The current moment can be any state of the terminal device. For example, the terminal device can be in an RRC active state. For example, the terminal device can be in an RRC idle state. For example, the terminal device can be in a PSM state.

[0113] The first satellite may be the satellite currently providing service to the terminal device, i.e., the current satellite. In other words, the terminal device has established a connection with the first satellite at the current moment, or the terminal device may establish a connection with the first satellite. Exemplarily, the terminal device is located within the geographic coverage area of ​​the first satellite. Exemplarily, the terminal device is currently located within the signal coverage area of ​​the first satellite.

[0114] As an example, at the current moment, the terminal device is in a scenario with network coverage.

[0115] In some embodiments, the terminal device is a communication device with a low service transmission rate or a small amount of data transmission. For example, the terminal device is a communication device in NB-IoT. In another example, the terminal device is a communication device in an MTC application.

[0116] In some embodiments, the terminal device supports energy-saving or low-power configurations. That is, the terminal device can achieve energy conservation during operation through parameters configured by the network device or core network. For example, the terminal device may support DRX configuration or eDRX configuration. For another example, the terminal device may support PSM configuration.

[0117] The first time information refers to a time parameter associated with a scenario where the terminal device is in discontinuous network coverage. In some embodiments, the first time information refers to a time parameter associated with a scenario where the terminal device enters a scenario where there is no network coverage from a scenario with network coverage. In some embodiments, the first time information refers to a time parameter associated with a scenario where the terminal device enters a scenario where there is network coverage from a scenario where there is no network coverage.

[0118] As an example, a terminal device entering a scenario without network coverage can also mean that the terminal device is in a scenario with discontinuous network coverage. Discontinuous network coverage can also be referred to as discontinuous cell coverage. That is, the terminal device may be within the coverage of a cell at certain times, but may not be within the coverage of any cell at other times.

[0119] As an example, when the terminal device is in cell coverage, the cell may indicate whether discontinuous coverage is supported through a system information block (SIB) and provide necessary information for discontinuous coverage prediction.

[0120] In some embodiments, the first time information includes the time when the terminal device may be out of network coverage, and therefore may also be referred to as out-of-coverage indication information. In some embodiments, the first time information may be used by the terminal device to release the RRC connection, and therefore may also be referred to as release assistance information. In some embodiments, the first time information is related to the unreachable state of the terminal device, and therefore may also be referred to as unreachable information.

[0121] The first time information is related to the first time period and / or the second time period. As an example, the first time information may include the first time period and / or the second time period. As an example, the first time information may be used to determine the first time period and / or the second time period.

[0122] As an example, the first time period or the second time period may include one or more time parameters of the time period, which may include the start time (starting moment), end time (ending moment) and duration of the time period.

[0123] As an example, the first time information may include at least one of the following: duration (duration) of no network coverage, time (moment) of entering no network coverage, and time (moment) of returning to network coverage.

[0124] In some embodiments, the first time information may indicate a time parameter for a first time period. The first time period is the period from the current moment to the moment when the terminal device begins to lose network coverage. In other words, after the first time period, the terminal device will lose network coverage. If the terminal device can predict the time of loss of coverage, the terminal device can check whether the remaining time of the current cell coverage is long enough to accommodate connection establishment, thereby ensuring that the terminal device can successfully establish communication with the network device. Furthermore, for terminal devices that are about to lose coverage, they can also prepare in advance to further save power consumption.

[0125] As an example, the first time period may indicate the start time when the terminal device leaves the satellite signal coverage area. This start time is also the critical time when the terminal device is at the edge of the satellite signal coverage. This start time is also the start time when the terminal device enters the period without network coverage.

[0126] As an example, the first time period is the time period when the terminal device reaches the edge of the current cell.

[0127] As an example, the terminal device will switch to other service cells before reaching the edge of the current cell. The first time period is the time period from the current position of the terminal device to the edge of other cells where cell switching is no longer performed.

[0128] As an example, the terminal device does not perform satellite switching before reaching the edge of the current cell, and the first time period is the time period from the current position to the edge of the current cell.

[0129] In some embodiments, the first time information may indicate a time parameter of the second time period. The second time period is a duration period without network coverage. That is, after the second time period, the terminal device will enter a scenario with network coverage. The second time period may also be referred to as a non-coverage gap or unavailable period. If the terminal device can determine the duration of the period without network coverage, the terminal device can be awakened in a timely manner when it enters network coverage based on the duration to ensure communication.

[0130] As an example, the start time of the second time period is the start time when the terminal device enters a state without network coverage, and the end time of the second time period is the time when the terminal device enters a state with network coverage from a state without network coverage.

[0131] In some embodiments, due to the periodic operation of the satellite constellation, the first and second time periods during which the terminal device enters a scenario without network coverage are also periodic. When the terminal device enters a scenario without network coverage, it may enter a network unreachable state such as PSM. Therefore, the first period during which the terminal device is awakened can be determined based on the periodic first and second time periods.

[0132] As an example, the first cycle can be used to determine the timing for the terminal device to be awakened from the sleep state / silent state / PSM state.

[0133] As an example, the time at which the terminal device re-enters the satellite signal coverage area can be determined based on the first time period and the second time period. Based on the time at which the terminal device re-enters the satellite signal coverage area, the terminal device can send a configuration interval of a request to the core network or network device to wake up the terminal device, that is, determine the first period for waking up the terminal device in the recommended information.

[0134] In some embodiments, the first time information may indicate time parameters of the first time period and the second time period. The terminal device may determine the duration of network coverage and the duration of no network coverage in discontinuous coverage based on the first time information, thereby recommending reasonable configuration parameters to the network device or core network to match the discontinuous coverage scenario.

[0135] As an example, the terminal device may determine the recommended configuration parameters, that is, the recommendation information, based on the first time information.

[0136] The terminal device may determine the first time information based on a variety of information. The terminal device may predict when discontinuous coverage will begin based on the time, thereby determining when to release the RRC connection to avoid triggering a radio link failure (RLF). Furthermore, the terminal device may synchronize the first time information with the network device to release the terminal device to the RRC idle state (RRC_IDLE) in a timely manner.

[0137] In some embodiments, the terminal device may determine the first time information by making a prediction based on one or more types of information. This or these types of information may also be referred to as necessary information for predicting discontinuous coverage. For example, the first time information may be related to one or more of the following: location information of the terminal device; relative location information between the terminal device and a first satellite; and information related to multiple satellites associated with the terminal device. The multiple satellites include the first satellite.

[0138] As an example, the first time information can be determined based on one or more of the above information.

[0139] In some embodiments, the terminal device may estimate the first time information based on its own location information. The location information of the terminal device may be determined based on a global navigation satellite system (GNSS). Exemplarily, the location information of the terminal device may include location change information of the terminal device. The location change information may be, for example, movement information of the terminal device.

[0140] As an example, when the terminal device is currently in an RRC activated state, the edge change of the serving cell can be determined based on communication with the satellite. The terminal device can estimate the time when it reaches the cell edge based on its own location information, thereby determining the first time period.

[0141] In some embodiments, the first time information may be determined based on relative position information between the terminal device and the first satellite. The relative position information may include an elevation angle of the terminal device relative to the first satellite and / or a distance between the terminal device and an edge of a service area of ​​the first satellite.

[0142] As an example, in the case of discontinuous coverage in an IoT NTN, the elevation angle value or elevation angle change rate of the terminal device relative to the first satellite can be used by the terminal device to determine whether it will enter discontinuous coverage. For example, when the elevation angle of the terminal device relative to the first satellite is less than 5 degrees, the terminal device can determine that it will soon leave the service area of ​​the first satellite.

[0143] As an example, the terminal device may determine whether it is about to leave the coverage of the first satellite based on its distance to the edge of the service area. For example, when the reference position of the terminal device to the cell edge is less than a certain set value, the terminal device will soon enter discontinuous coverage.

[0144] In some embodiments, the first time information may be related to the terminal device's location information and the ephemeris information / position information of the first satellite. For example, the terminal device may obtain the ephemeris information of the first satellite based on an ephemeris table. The terminal device may determine the remaining duration within the coverage area of ​​the first satellite based on its own location and ephemeris information, and thereby determine the first time information based on this duration. Based on this first time information, the terminal device may determine the duration of time, as specified in the recommended information, for which the terminal device can be awakened.

[0145] As an example, for terrestrial fixed cells served by non-geostationary orbit (NGSO) satellites, the network can provide the cell downtime. Alternatively, the terminal device can estimate its arrival time at the cell edge based on the service time (T-service). Alternatively, the terminal device can estimate satellite parameters and first time information based on GNSS positioning information.

[0146] As an example, for a mobile cell, the network cannot provide a downtime. Therefore, the terminal device can predict the duration of the cell service based on the reference position of the first satellite in the broadcast. For example, the terminal device can use the satellite position (x, y, z) calculation formula mentioned above to predict the cell service time.

[0147] In some embodiments, the first time information may be determined based on information related to multiple satellites associated with the terminal device. The multiple satellites associated with the terminal device may refer to satellites that are currently or may soon provide services to the terminal device. Exemplarily, the multiple satellites include a first satellite currently providing services to the terminal device. Exemplarily, the multiple satellites also include one or more satellites other than the first satellite. The one or more satellites may be any one or more satellites that may soon provide services to the terminal device.

[0148] As an example, the plurality of satellites may be some or all of the satellites in a satellite constellation associated with the terminal device.

[0149] As an example, in a mobile cell, a serving cell is generally an area served by one or more satellites. The serving cell may be the serving cell where the terminal device is located. The plurality of satellites may include satellites providing services for the serving cell.

[0150] In some embodiments, the information related to the multiple satellites may include at least one of ephemeris information of the multiple satellites, position information of the multiple satellites, beam information of the multiple satellites, and time information of when the multiple satellites provide services to the terminal device. Since the multiple satellites include the first satellite, the information related to the multiple satellites also includes information related to the first satellite.

[0151] In some embodiments, information related to multiple satellites may be carried in a SIB. The network device may broadcast the SIB so that the terminal device can receive information related to multiple satellites. For example, the network device may indicate support for discontinuous coverage by broadcasting SIB32 or other information blocks containing first satellite information (e.g., ephemeris and beam information). SIB32 will be used as an example for further explanation.

[0152] As an example, relevant information of multiple satellites may be carried in one or more of the following information: SIB3, SIB31, and SIB32.

[0153] As an example, information related to the first satellite can be included in the assistance information. When the terminal device is in an NTN network, the assistance information may include information related to the satellite's network coverage, such as the satellite's ephemeris information. Based on the assistance information, the terminal device can predict whether it will lose the satellite's network coverage or whether it is still within the satellite's network coverage, thereby determining the time information related to the loss of network coverage.

[0154] As an example, information related to satellites other than the first satellite among the multiple satellites may also be transmitted via RRC signaling. For example, after receiving the first time information, the first satellite may notify the terminal device via RRC-specific signaling whether there are other mobile satellites nearby. If there are other satellites, the terminal device may be further notified of the ephemeris parameters of the other satellites.

[0155] Alternatively, the first time information may be determined based on the ephemeris information or position information of multiple satellites. The ephemeris information of multiple satellites may be used to determine the position information of the multiple satellites. For example, the position information of the satellites may be determined based on the ephemeris table and the epoch time.

[0156] As an example, when the relevant information of multiple satellites includes position information of multiple satellites, the terminal device can estimate the trajectory of the serving cell on the earth by predicting the position information.

[0157] As an example, by obtaining the position information of multiple satellites or any one of the multiple satellites, the trajectory of the satellites at different times can be depicted. The terminal device can predict the time of entering and leaving the satellite coverage based on the trajectory parameters.

[0158] As an example, the terminal device can predict the time when other satellites will cover itself and the time when it will leave the current service satellite (the first satellite) through the satellite and ephemeris parameters of other surrounding movable satellites sent by the first satellite.

[0159] As an example, the orbit of any satellite among the multiple satellites may have slight changes. To ensure the accuracy of the prediction, the terminal device can regularly update the prediction results.

[0160] Optionally, the first time information can be determined based on the satellite's beam information, thereby more accurately predicting the remaining time that the terminal device will be within the satellite's coverage. For scenarios involving mobile cells, if the terminal device makes predictions based solely on the satellite's ephemeris information, large deviations may occur. For example, since the beam center of the satellite in Figure 4 is not perpendicular to the satellite position, ephemeris alone may not be sufficient for the terminal device to determine whether it will be within the satellite's coverage at a given time. In other words, discontinuous coverage predicted based solely on ephemeris information may be incorrect. To improve accuracy, the necessary information for predicting discontinuous coverage may include ephemeris and beam information for multiple satellites.

[0161] As an example, when the SIB contains beam information of any satellite among multiple satellites, it can indicate that the cell supports discontinuous coverage. That is, the information in the SIB can implicitly indicate whether the cell indicates discontinuous coverage. For example, when SIB32 contains beam information of the serving satellite, SIB32 can indicate that the cell of the serving satellite supports discontinuous coverage. Based on the beam information in the SIB, the terminal device can more accurately predict how long it can stay within the coverage of the first satellite. Combined with the location information of the terminal device and the satellite, the terminal device can roughly know when it will enter discontinuous coverage. For another example, when SIB32 does not contain beam information, it indicates that it is not supported.

[0162] As an example, when the SIB includes beam information of any one of multiple satellites, the terminal device sends the first time information.

[0163] Optionally, the first time information can be determined based on time information when multiple satellites provide services to the terminal device. The time information when multiple satellites provide services can be determined based on ephemeris information and beam information of the multiple satellites. Exemplarily, the duration of the services provided by the multiple satellites can be used to determine the first time period and / or the second time period.

[0164] As an example, the first duration is the remaining duration of service provided by the first satellite. That is, the first duration is the duration between the current moment and the moment when the terminal device leaves the service area of ​​the first satellite. The second duration indicates the time information when multiple other satellites cover the terminal device. Multiple other satellites may have multiple starting moments of coverage of the terminal device. There are multiple durations between the current moment and the multiple starting moments, and the minimum of the multiple durations is the second duration. That is, the second duration is the minimum of one or more durations between the current moment and one or more moments when one or more satellites begin providing service to the terminal device. The first time period can be determined based on the first duration and the second duration.

[0165] For example, when the first duration is greater than or equal to the second duration, the duration of the first time period is greater than the first duration.

[0166] For another example, when the first duration is less than the second duration, the duration of the first time period is equal to the first duration.

[0167] For another example, when the terminal device does not perform satellite switching before leaving the first satellite service area, the duration of the first time period is the first duration.

[0168] The first time information may be carried in a variety of information. Optionally, the first time information may be carried in one or more of the following information: auxiliary information of the terminal device, a downlink channel quality report (DCQR), and an access stratum release assistance indication (AS RAI).

[0169] In some embodiments, the terminal device may report the first time information to the first satellite via RRC-specific signaling. The RRC-specific signaling may include auxiliary information of the terminal device.

[0170] In some embodiments, the first time information may be carried in a newly added information field. For example, an information field for sending the first time information may be added based on the DCQR. In another example, a corresponding information field for sending the first time information may be added based on the AS RAI.

[0171] As an example, the terminal device can send an AS RAI command carrying the first time information to the NB module. The module carries the AS RAI when sending a CON or NON message to the NB-IoT, thereby enabling the transmission of the first time information.

[0172] Continuing to refer to FIG. 7 , in step S720 , based on the first time information, the terminal device performs a transition from the first state to the second state.

[0173] The first state may be the state of the terminal device at the current moment, or the state at another moment, which is not limited here.

[0174] The second state may be any state different from the first state. In some embodiments, the first state and the second state may be any two of the RRC active state, the RRC idle state, and the PSM state. In other words, the state transition performed by the terminal device may include a transition between any two of the RRC active state, the RRC idle state, and the PSM state.

[0175] As an example, the first state is the RRC activated state, and the second state is the RRC idle state.

[0176] As an example, the first state is a PSM state, and the second state is an awake state. The PSM state may also be called an unreachable state.

[0177] As an example, the first state is the RRC idle state or the PSM state, and the second state is the RRC active state.

[0178] When the terminal device performs a transition from the first state to the second state, the terminal device may transition from the first state to the second state according to a transition timing, or may determine whether to transition from the first state to the second state. In other words, the terminal device may not perform a state transition.

[0179] Based on the first time information, it can refer to the terminal device directly performing a state transition according to the first time information, or it can refer to the network device sending a transition indication based on the first time information, and the terminal device performing a state transition according to the transition indication sent by the network device. As can be seen from the foregoing, the first time information can indicate a period of time when the terminal device is unreachable. Both network device-centric and terminal device-centric processes can be used to determine and coordinate the period of time when the terminal device is unreachable. These two methods are not mutually exclusive. They can serve different use cases and can coexist in the same network. The following text will introduce the method embodiments of state transition centered on terminal devices and network devices respectively.

[0180] In some embodiments, when the first state is the RRC idle state or the PSM state, the first time information can be used by the terminal device to determine whether to establish a connection. As an example, the first time information also includes a third time period during which the first serving cell provides service to the terminal device, and the duration of the third time period is used by the terminal device to determine whether to establish an RRC connection with the first serving cell.

[0181] For example, when the first serving cell is currently served by the first satellite, the third time period represents the remaining duration during which the first satellite can provide service to the terminal device. If the remaining duration is insufficient to establish a connection, the terminal device may not establish a connection with the first satellite. If the remaining duration is sufficient to establish a connection, the terminal device may establish an RRC connection with the first satellite to ensure communication if there is service demand.

[0182] For another example, the first serving cell may be a cell provided by other satellites when the terminal device switches to other satellites. Similarly, the third time period may also represent the remaining time for other satellites to provide services to the terminal device, which will not be described in detail here.

[0183] As an example, when the terminal device does not switch before reaching the edge of the current serving cell, the third time period is the first time period.

[0184] As an example, when the duration of the third time period is less than or equal to the first threshold, the terminal device does not establish an RRC connection to avoid connection failure and reduce power consumption caused by establishing the connection.

[0185] In the process of state transition centered on the terminal device, the terminal device can determine the first time information related to no network coverage based on a variety of information, and send the first time information to the network device. Although the network device may have more accurate coverage data than the terminal device, the network device generally cannot know its location as accurately as the terminal device. In addition, in some cases in NB IoT, the terminal device may not send a location report to the network device (e.g., eNB), which means that the terminal device's estimate of being in no network coverage will be more accurate than the network device's estimate. Furthermore, if the terminal device predicts the first time information, even if the signal is lost in the RRC connected state, because it knows that it is about to enter a state of no network coverage, it does not need to go through the power-expensive RLF declaration process.

[0186] In some embodiments, after the terminal device determines the first time information, the terminal device may send the first time information to the network device. After receiving the first time information, the network device may send first indication information to the terminal device. The first indication information may indicate whether the terminal device is transitioning from the first state to the second state, or may indicate the timing of the state transition for the terminal device.

[0187] As an example, the first indication information includes a transition timing of the terminal device from the RRC active state to the RRC idle state. For example, the first indication information can indicate the transition timing by configuring a transition timer for the terminal device to avoid autonomous transition of the terminal device.

[0188] As an example, the terminal device notifies the network device of an unreachable period of the terminal device and / or an indication of leaving or entering a coverage area (first time information). Further, when the terminal device is in an RRC connected (RRC_CONNECTED) state, the network device or the terminal device may configure the terminal device to report the indication via a first timer. The first timer is, for example, an out-of-coverage timer.

[0189] Exemplarily, the value of the first timer may be configured by the network device or configured by the terminal device itself.

[0190] Exemplarily, when the value of the first timer is configured to zero, the terminal device can immediately release the RRC connection and enter the RRC idle state.

[0191] Exemplarily, the configuration or sending information of the first time information may introduce a new indication from an uplink dedicated control channel (UL DCCH) message, or may use an existing AS RAI.

[0192] As an example, when the terminal device sends the first time information to the network device, the terminal device may start a first timer.

[0193] As an example, after the network device receives the first time information, the network device may also start a first timer.

[0194] As an example, after predicting when discontinuous coverage will begin, the terminal device may send first time information to the network device. The terminal device or the network device may start a first timer. Upon expiration of the first timer, the terminal device may, based on the behavior of the network device, terminate the RRC connection and enter the RRC idle state. The reason for the RRC release may be marked as "other."

[0195] For example, when the first timer is running, the terminal device may send the first time information to the network device. Before leaving the first satellite service area, the network device continues to provide services to the terminal device. Any uplink / downlink transmission between the terminal device and the network device may continue. In addition, during this period, the network device may also choose to reconfigure the terminal device to disable or stop the first timer.

[0196] In some embodiments, the terminal device may also autonomously enter the RRC idle state. Optionally, the terminal device may determine the transition timing for the state transition based on the first timer, rather than determining the transition timing based on an instruction from the network device.

[0197] As an example, a first timer may be set in the terminal device. The terminal device may start the first timer when sending the first time information. When the first timer expires, the terminal device autonomously leaves the RRC connection and enters the RRC idle state. The reason for RRC release may also be marked as "other."

[0198] As an example, when the terminal device releases the RRC connection based on the first timer, the RRC release cause can be marked as a new cause. When entering a scenario without network coverage, the network device can send an RRC release (RRCRelease) message to the terminal device with the new cause.

[0199] As an example, the first timer can be used by the terminal device to determine the transition timing from the RRC active state to the RRC idle state.

[0200] As an example, the terminal device may also send a second indication message to the network device. The second indication message may indicate that the RRC idle state is the preferred state. The second indication message may also be used by the terminal device to determine the transition timing from the RRC active state to the RRC idle state based on the first timer. When the first timer expires, the terminal device may transition from the RRC active state to the RRC idle state. That is, if the first timer expires, the terminal device may directly perform the state transition regardless of whether the first indication message from the network device is received.

[0201] As an example, since the terminal device knows its own coverage, it can indicate to the network that "RRC_IDLE" is the preferred RRC state when starting the first timer. If no RRC release indication is received when the first timer expires, the terminal device autonomously enters RRC_IDLE.

[0202] Whether the transition timing is determined by the network device or by the terminal device itself, it is related to one or more of the following information: the terminal device's service type, the terminal device's service priority, and the network device's downlink data. The following article will explain the state transition process in detail, focusing on the network device.

[0203] In some embodiments, when the terminal device determines that it is about to enter a scenario without network coverage, the first time information may also indicate an instruction for the terminal device to leave the RRC connection. Based on this information, the network device may determine that it is time to release the terminal device. Releasing the terminal device means transitioning the terminal device from the RRC active state to the RRC idle state.

[0204] As an example, if the network device deems it necessary, it can prevent the terminal device from autonomously entering the idle state by releasing the timer configuration.

[0205] In some embodiments, when the terminal device predicts the arrival of a non-coverage gap, it can autonomously release the existing RRC connection. If the terminal device does not have enough time to complete the RRC re-establishment process due to discontinuous coverage, the terminal device can determine the timing of switching to the RRC idle state based on the situation of triggering RLF. Exemplarily, when the actual time when the terminal device enters a situation without network coverage is earlier than the time indicated by the first time information, the terminal device may enter a scenario without network coverage in advance. In this scenario, the terminal device may not be aware that it has entered a scenario without network coverage, but initiates a request for RRC re-establishment due to loss of signal, resulting in RLF.

[0206] As an example, the terminal device may directly switch to the RRC idle state after triggering RLF. That is, when the terminal device predicts that it is about to enter a scenario without network coverage, it directly releases the RRC connection with the network (NW) once RLF is triggered.

[0207] As an example, when the terminal device switches to the RRC idle state after the number of RLF triggering exceeds the threshold value. For example, when RLF is triggered N times, the terminal device switches from the RRC active state to the RRC idle state. Where N is a natural number greater than or equal to 1.

[0208] In some embodiments, in order to avoid a mismatch in the RRC connection state, the terminal device may trigger a request to release the RRC connection before the actual RLF event. By triggering this request, the terminal device can notify the network of the RRC connection release. This approach may cause the RRC connection to be released earlier than the actual RLF situation, thereby affecting data transmission. If early release is to be avoided, the terminal device can implicitly release on RLF, that is, release the RRC connection when RLF is triggered. However, the network should be aware of the behavior of the terminal device so that it can decide on the UE context to be released locally based on the data transmission status and the latest reported radio conditions.

[0209] In some embodiments, when the terminal device knows that no network coverage is about to begin and the remaining time in the current cell is insufficient to complete the new connection establishment process, the decision whether to trigger re-establishment or enter the RRC idle state can also be made based on the implementation of the terminal device.

[0210] The previous section described the state transition process centered around terminal devices. Now, we'll explain the state transition process centered around network devices. In this process, the network device can detect the activity of terminal device services and determine the timing for terminal device state transitions. It should be understood that terminal devices can also independently determine the timing for state transitions based on service types, which will not be discussed further here.

[0211] In some embodiments, the network device may be any of the aforementioned base stations or network-side devices other than the communication devices corresponding to the core network. For example, when the base station is located on a satellite, the network device may refer to the satellite. For example, when the base station is located on the ground and the satellite is used only for transit, the network device may include both the satellite and the base station.

[0212] As an example, the network device includes a first satellite, and the terminal device is located in the service area of ​​the first satellite at a current moment.

[0213] During the network-centric transition process, the terminal device maintains an RRC connection with the network device. The network device can understand the terminal device's service status based on communication with the terminal device and instruct the terminal device on the state transition. Furthermore, the terminal device also sends the first time information to the network device to minimize possible state mismatches between the terminal device and the network device.

[0214] In some embodiments, the network device may also determine the first time information by detecting the service activity level of the terminal device. In other words, the network device may receive the first time information sent by the terminal device, or may determine the first time information independently. Based on the first time information, the network device may instruct the terminal device to execute a transition from the first state to the second state.

[0215] In some embodiments, when the terminal device notifies the network device of the first time information of leaving the coverage area, the network device can determine whether to immediately allow the terminal device to release the RRC connection and enter the RRC idle state. In other words, the network device can determine the switching timing.

[0216] As can be seen from the foregoing, the timing of the conversion may be related to the service type and service priority of the terminal device and the downlink data of the network device.

[0217] As an example, the network device may set an activity factor function related to the service type and / or service priority of the terminal device to determine the transition timing. Exemplarily, the network device may detect the activity level of the terminal device service and configure the transition timing for the terminal device supporting DRX to perform state transition. Exemplarily, the activity factor function may be a first factor δ(x, y). Wherein, x may be related to the service type, y may be related to the service priority, and 0<δ(x, y)≤1.

[0218] As an example, the network device can configure the conversion timing according to the downlink data transmission requirements to avoid downlink data loss. For example, in order to avoid the loss of the sent downlink data, the network device can instruct the terminal device to enter the RRC idle state in advance. Since the network device knows the timing when the terminal device enters the idle state, if the network device still has downlink data to send, the downlink data can be stored and buffered, and then sent when the terminal device is connected again. The situation in which the terminal device is connected again is, for example, when a new satellite covers the terminal device, when the terminal device switches to another satellite, or when the terminal device receives a wake-up signal.

[0219] Exemplarily, the fourth time period between the transition timing and the current moment is the product of the first time period and a second factor, where the second factor is greater than 0 and less than 1. The second factor is, for example, α. When the first time period is the first duration, the first time period can be represented as T1. The network device can instruct the terminal device to enter the RRC idle state after a time period of α*T1 (1>α>0).

[0220] As shown in Figure 7, after predicting the first time information, the terminal device can perform state transition independently or according to the instruction of the network device. Generally, the terminal device will know the coverage discontinuity when it is in connected mode, and the terminal device can decide to release the RRC connection instead of triggering the re-establishment process, thereby reducing power consumption.

[0221] As mentioned above, before a terminal device leaves the service area of ​​a first satellite, it may receive ephemeris information and / or beam information from other satellites. The terminal device can determine whether to perform a satellite handover. Satellite handover can delay the time it takes for the terminal device to enter a state without network coverage. Furthermore, the terminal device can perform a state transition after performing a satellite handover. As an example, the terminal device can determine whether to perform a satellite handover or a state transition based on the first and second durations described above.

[0222] In some embodiments, a terminal device may determine the timing of executing a state transition based on information related to multiple satellites. The information related to the multiple satellites may be used to determine the first duration and the second duration. For ease of understanding, the process of executing a state transition based on the first duration and the second duration is illustrated below with reference to FIG8 . This process includes multiple steps.

[0223] In step S1 , a network device may send the ephemeris and beam information of a first satellite via broadcast.

[0224] Step S2: The terminal device predicts a first time duration when it will leave the first satellite based on its own location information and broadcast information.

[0225] Step S3: The first satellite notifies the ephemeris parameters of one or more surrounding satellites through RRC dedicated signaling based on the first duration.

[0226] In step S4, the terminal device predicts multiple durations of coverage from the current time to the start time of coverage of one or more satellites based on the received ephemeris parameters of these satellites. The minimum value of the multiple durations is the second duration. The satellite corresponding to the second duration is the second satellite. Furthermore, the terminal device may also predict the time when the coverage of one or more satellites ends to determine the durations of the first time period and the second time period.

[0227] In step S5, the terminal device may determine how to deal with a scenario without network coverage based on the relationship between the first duration and the second duration.

[0228] Exemplarily, when the first duration is greater than or equal to the second duration, the terminal device performs switching from the first satellite to the second satellite corresponding to the second duration according to the first condition; when the first duration is less than the second duration, the terminal device switches from the RRC active state to the RRC idle state.

[0229] As an example, the first condition is related to a handover condition for the terminal device to perform satellite handover and / or a service requirement of the terminal device. The handover condition for performing satellite handover includes factors affecting handover, such as signal measurement results.

[0230] As an example, if the first duration is greater than or equal to the second duration, the terminal device may first switch from the first satellite (source satellite) to the second satellite (target satellite) if the switching conditions are met. After the satellite switching is successful, the terminal device may choose whether to enter the RRC idle state within the service area of ​​the second satellite based on the current service status.

[0231] As an example, if the first duration is greater than or equal to the second duration and the handover condition is not met, the first satellite may send a handover command to the terminal device to reduce power consumption caused by the terminal device continuously performing measurements and sending measurement reports. The terminal device may determine whether to perform a handover from the first satellite to the second satellite based on the first condition.

[0232] For example, the first condition may be whether the terminal device has a service requirement. If the terminal device has a service requirement, the terminal device performs a handover from the first satellite to the second satellite. If the terminal device does not have a service requirement, the terminal device may transition from the RRC active state to the RRC idle state. For example, the terminal device may indicate to the network device an instruction to leave the RRC connection, causing the network device to determine that the terminal device can be released. Similarly, if required by the network, a release timer configuration may be configured to prevent the terminal device from autonomously entering the idle state.

[0233] As an example, if the first duration is less than the second duration, the terminal device may transition from the RRC active state to the RRC idle state autonomously or upon instruction from the network device. When the terminal device leaves or is about to leave the coverage of the first satellite, the terminal device may send first time information to the network device based on a prediction. This information helps the network device efficiently utilize resources. If the network device does not expect the terminal device to further transmit uplink and downlink data, the terminal device is released to the RRC idle state.

[0234] The method in Figure 8 is executed by a terminal device. In step S810, the terminal device determines a first duration and a second duration.

[0235] In step S820, it is determined whether the first duration is less than the second duration. If so, step S830 is executed; otherwise, step S840 is executed.

[0236] In step S830, the RRC active state is converted to the RRC idle state. The terminal device can perform this operation autonomously or according to an instruction.

[0237] In step S840, satellite switching is performed according to the first condition.

[0238] The above descriptions, in conjunction with Figures 7 and 8, respectively describe embodiments of a method for coping with discontinuous coverage centered on a terminal device and centered on a network device. Through these embodiments, the terminal device can determine, based on the first time information, when to release the RRC connection or be awakened, to match the time when there is no network coverage, thereby saving power consumption or ensuring the success rate of communication establishment in the case of discontinuous coverage.

[0239] As mentioned previously, the coverage status of a terminal device is typically known only to the terminal device and the access network; the core network may not be aware of this coverage. However, in IoT or MTC applications, the core network must configure the terminal device's DRX / eDRX cycle and PSM state in idle mode. Therefore, in scenarios with discontinuous coverage, it is important to consider how to properly match the terminal device's coverage status with the core network configuration.

[0240] To address the above issues, embodiments of the present application provide another method for wireless communication. Using this method, first time information determined by a terminal device can be used by the core network to determine a first configuration parameter, which is used to instruct the terminal device to perform a state transition. This indicates that the core network considers the time information when there is no network coverage during configuration, thereby enabling the configuration of a more appropriate energy-saving mode.

[0241] For ease of understanding, another method for wireless communication according to an embodiment of the present application is described in detail below with reference to Figure 9. The method shown in Figure 9 is related to the method shown in Figure 7, and for the sake of brevity, the terminology explained in Figure 7 will not be repeated.

[0242] Figure 9 illustrates the interaction between a terminal device, network equipment, and the core network. The terminal device is currently located within the service area of ​​the first satellite in the NTN. The core network's corresponding communication device can be a network element or entity within the core network.

[0243] Exemplarily, the communication device corresponding to the core network may include an MME or an AMF. The AMF / MME may determine the configuration parameters of the DRX, eDRX, or PSM mode when the terminal device is in an unreachable state.

[0244] For example, when the base station is deployed on a satellite, the ground equipment only includes the core network. In this scenario, the PLMN is also the core network.

[0245] Referring to Figure 9, in step S910, the terminal device sends first time information. This first time information is the first time information determined by the terminal device in Figure 7. The first time information is related to the first time period and / or the second time period, and will not be further described here. It should be understood that the second time period can be the duration of a period of network coverage or unavailability, or can also represent the duration of a period when the terminal device is unreachable.

[0246] As shown in Figure 9, the terminal device sends the first time information to the network device. In step S920, the network device forwards the first time information to the core network. Regardless of whether the base station is deployed on the first satellite, the network device includes a first satellite for receiving the first time information.

[0247] In some embodiments, the base station is deployed on a first satellite and the core network is deployed on the ground. The terminal device sends the first time information to the base station on the first satellite, and the base station forwards the first time information to the core network on the ground.

[0248] In some embodiments, the base station and the core network are both located on the ground. The terminal device transmits first time information to a first satellite, and the first satellite forwards the first time information to the base station or the core network on the ground. The communication device corresponding to the core network communicates with the terminal device via the first satellite.

[0249] As an example, after the terminal device predicts and estimates the first time information, the terminal device can report the time parameters of the first time period and the second time period. After receiving the information, the network device can send it to the AMF / MME via a NAS message.

[0250] As an example, the network device may also estimate and predict the first time information of the terminal device based on the location information of the terminal device and information of other adjacent satellites.

[0251] In step S925 , the core network determines the first configuration parameter.

[0252] In some embodiments, the first time information is used by the core network to determine the first configuration parameter of the terminal device. That is, the core network can determine the configuration parameter of the terminal device, i.e., the first configuration parameter, based on the first time information. When the core network configures the parameters of the eDRX configuration and / or PSM configuration for the terminal device based on the first time information, it can ensure that the terminal device is awakened when it is within the coverage of the satellite signal, thereby smoothly receiving the signal from the satellite. As an example, when the MME provides a timer (e.g., a periodic TAU timer, an eDRX mode, and a PSM mode configuration) to the terminal device, the duration of the unavailable period (no network coverage or the terminal device is unreachable) related to the first time information and the start time of the unavailable period can be considered.

[0253] As an example, the core network can set a cache timer based on the second time period in the first time information. For example, after receiving the first time information, the PLMN can set a corresponding timer T2 based on the terminal device's predicted and estimated second time period. During timer T2, if a page is required for the terminal device, the PLMN will store the information. After the second time period has expired, the PLMN will send its cached data to the NTN network, and the NTN network will forward the corresponding information to the terminal device.

[0254] As an example, the duration of the buffer timer is set to be greater than one or more DRX cycles or eDRX cycles to avoid the network device from paging the terminal device when the device is out of the coverage of the satellite, thereby wasting resources.

[0255] As an example, the core network may determine a first mode of the terminal device. Configuration parameters of the first mode are the first configuration parameters.

[0256] In some embodiments, the first mode is any one or more energy-saving modes configured by the core network for the terminal device, so as to perform reasonable energy-saving configuration in the case of discontinuous network coverage and save power consumption of the terminal device.

[0257] The first mode may include one or more of the following: DRX mode, eDRX mode, and PSM mode. As an example, the first mode may be any of the above three modes. As an example, the first mode may include the above three modes or any two of the above three modes. For example, in the Internet of Things, the first mode includes the eDRX mode and the PSM mode.

[0258] In some embodiments, the first mode can be determined based on a recommendation from the terminal device. For example, the terminal device can indicate its recommended mode in the first time information, or can include parameter information of the recommended mode, i.e., first recommended parameters, in the first time information. For example, the terminal device can send the first recommended parameters after sending the first time information.

[0259] As an example, when the terminal device is in a communication scenario with discontinuous coverage of satellite signals, it can determine a DRX mode, eDRX mode and / or PSM mode suitable for itself based on the first time information. For example, when the second time period is relatively short, that is, when the time when the satellite is not covered is relatively short, the terminal device is suitable for the DRX mode. For another example, when the second time period is relatively long, that is, when the time when the satellite is not covered is relatively long, the terminal device is suitable for the eDRX mode. For another example, when the second time period is long, the terminal device is suitable for the PSM mode.

[0260] As an example, the terminal device may also determine its appropriate DRX mode, eDRX mode, and / or PSM mode based on the service type. For example, when the service type of the terminal device requires relatively frequent data transmission, the DRX mode is applicable. For another example, when the service type of the terminal device has a relatively long data transmission interval, the PSM mode is applicable.

[0261] In some embodiments, the first configuration parameter may also be determined based on a recommended parameter of the terminal device. For example, the PLMN network may determine the first configuration parameter based on the first recommended parameter of the terminal device. Thus, the terminal device and the core network may negotiate appropriate configuration parameters (e.g., timer length) for the relevant PSM / eDRX scheme in the case of discontinuous network coverage.

[0262] For example, in the case of discontinuous coverage on an NTN, the misalignment between the PTW and the coverage window needs to be resolved. The NAS layer between the terminal device and the core network can negotiate relevant parameters to support discontinuous coverage. For example, the terminal device and the core network can negotiate the configuration of various timers to ensure mobility management functions and energy-saving optimization of the terminal device.

[0263] As an example, a terminal device can report to the core network recommended DRX, eDRX, PSM, etc. based on its service type, and can negotiate with the AMF / MME to support discontinuous coverage. The MME can consider this recommendation when providing timers to the terminal device. For example, the AMF / MME can configure a variable period or TAU timer, DRX, eDRX, and PSM mode configuration for the terminal device.

[0264] As an example, the terminal device may determine the first recommended parameter based on the first time information and the service type. The terminal device may forward the first recommended parameter to the core network via the network device, so that the core network can determine the first configuration parameter. When the core network determines the first configuration parameter based on the first recommended parameter, it is beneficial to ensure that the terminal device can have good communication quality when communicating in a mode such as eDRX and PSM in a scenario with discontinuous satellite signal coverage, and further reduce the power consumption of the terminal device.

[0265] As an example, the first recommended parameters include TAU, eDRX, PSM and other related parameters recommended by the terminal device.

[0266] As an example, the terminal device may send the determined DRX, eDRX configuration and / or PSM configuration parameters applicable to the satellite signal discontinuous coverage communication scenario as reporting information to the core network. The core network may refer to the DRX, eDRX configuration and / or PSM configuration parameters recommended by the terminal device and configure the DRX, eDRX configuration and / or PSM configuration that matches the communication scenario for the terminal device.

[0267] As an example, when the terminal device determines that the applicable mode is the DRX mode, it can determine the recommended parameters of the DRX configuration suitable for the communication scenario. The first recommended parameters may include the recommended parameters of the DRX configuration, such as the time parameters and timer parameters of the TAU.

[0268] As an example, when the terminal device determines that the applicable mode is the eDRX mode, it can determine the recommended parameters of the eDRX configuration suitable for the communication scenario. The first recommended parameters can include the recommended parameters of the eDRX configuration, such as the eDRX cycle.

[0269] As an example, when the terminal device determines that the applicable mode is PSM mode, it can determine recommended parameters for the PSM configuration suitable for the communication scenario. The first recommended parameters may include recommended parameters for the PSM configuration, such as the PSM duration. As an embodiment, the terminal device can recommend directly entering the PSM state in the communication scenario.

[0270] As an example, when the communication scenario determined by the terminal is applicable to both the eDRX mode and the PSM mode, recommended parameters of the eDRX configuration and the PSM configuration suitable for the communication scenario may be determined. The first recommended parameters may include these parameters.

[0271] In some embodiments, the first mode may also be determined according to the capabilities of the terminal device. As can be seen from the foregoing, the core network may determine the first mode corresponding to the capabilities supported by the terminal device, which will not be described in detail here.

[0272] In some embodiments, the first mode can be determined based on any combination of the above-mentioned multiple types of information.

[0273] In some embodiments, the first configuration parameters may include any one or more parameters related to the first mode, which are not limited herein. Exemplarily, the first configuration parameters include new TAU, eDRX, DRX, and PSM timer parameters. Exemplarily, the first configuration parameters may include parameters such as the period, start time, offset value, duration, and timer configuration parameters of the first mode. Exemplarily, the first configuration parameters may be used by the terminal device to execute the first mode.

[0274] As an example, the first configuration parameter may include time parameters of a second timer and a third timer. The second timer is used to determine the duration that the terminal device is in the radio resource control RRC idle state. The second timer is, for example, a T3324 timer. The third timer is used to determine the duration that the terminal device is in the PSM state. The third timer is, for example, a T3412 timer. The start time of the second timer and the third timer may be the end time of the first time period. That is, both timers are started when the first time period ends. Therefore, the duration of the third timer is greater than the duration of the second timer. For example, the duration of the third timer is the sum of the second timer and the PSM state duration.

[0275] As an example, the setting of the second timer can be determined based on the first time period. For example, the start time of the second timer is the end time of the first time period (the start time of the second time period). In another example, the duration of the second timer can be dynamically adjusted based on the duration of the first time period to ensure that the device matches the unreachable time and the dormant state when the NTN is not covered.

[0276] For example, the second timer starts counting from the end of the first time period, and when the second timer expires, the terminal device immediately enters the PSM state.

[0277] As an example, when the terminal device directly enters a scenario without network coverage in the RRC activation state, the duration of the second timer can be adaptively increased, which helps to match the existing energy-saving configuration with the scenario without network coverage.

[0278] As an example, the duration of the third timer can be determined based on the second time period to ensure that the end time of the PSM state matches the end time of no network coverage or device unreachability, thereby preventing the terminal device from being awakened when there is no network coverage. The second time period may refer to the entire time period that the terminal device predicts and estimates that it will not be covered by the network.

[0279] As an example, the end time of the third timer is no earlier than the end time of the second time period. In other words, the end time of the third timer can be equal to or later than the end time of the second time period. When the end time of the third timer is the end time of the second time period, the end time of the PSM state can be the end point where the device is unreachable or has no network coverage. When the end time of the third timer is later than the end time of the second time period, the end time of the PSM state can be the same as the original end point.

[0280] As an example, when the end moment of the second time period is later than the start moment of a TAU cycle, the terminal device is in the PSM state throughout the TAU cycle.

[0281] In some embodiments, the network device may receive first time information from the terminal device. When the first time information indicates a first time period, the network device may instruct the terminal device to enter the RRC idle state after the first time period has elapsed. Alternatively, the terminal device may autonomously enter the RRC idle state based on the predicted length of the first time period. Although the terminal device enters the RRC idle state, the terminal device cannot receive paging because it enters a network coverage scenario after the first time period. In this scenario, the duration of the second timer may be reduced so that the terminal device quickly enters the PSM state. As the time in the PSM state increases, power saving can be further achieved.

[0282] As an example, when the second timer is a T3324 timer and the third timer is a T3412 timer, the ratio of the duration of the second timer to the duration of the third timer is less than the first parameter. The first parameter may be A, 0<A<0.5. A is, for example, 0.25.

[0283] To facilitate understanding, the following describes the timer configuration parameters using the T3324 timer and the T3412 timer in Figure 5 as examples, combined with the two examples in Figure 10. The T3324 timer represents the second timer, and the T3412 timer represents the third timer. It should be noted that this is merely an example; the second and third timers can also be other timers used to determine corresponding durations.

[0284] Referring to Figure 10, T1 represents the first time period and T2 represents the second time period. Compared to Figure 5, in Examples 1 and 2, the start time of the T3324 timer and the T3412 timer are both advanced to the end time of the first time period. Because the terminal device is in the RRC activated state at the end time of the first time period, the start time of both timers is advanced from the original idle state start time to the active state period.

[0285] Comparing Example 1 and Example 2, it can be seen that the duration of the T3324 timer in Example 1 is much longer than the duration of the T3324 timer in Example 2, so Example 2 can achieve further power saving.

[0286] In Figure 10 , the end time of the T3412 timer is the end time of the second time period. It should be noted that the end time of the T3412 timer can also be the original end point of the first figure in Figure 10 .

[0287] In some embodiments, when the first mode is the eDRX mode, the first configuration parameter may include configuration parameters for the eDRX mode. As an example, the first configuration parameter may determine a PTW time parameter within each eDRX cycle. The PTW time parameter may also be replaced with an actual PTW window. The terminal device or network device may calculate a PTW calculation window based on the cycle information sent by the core network, and then adjust the calculated window to determine the actual PTW window.

[0288] As an example, the time parameters of PTW can be determined based on the calculation window of PTW and the first time information. The calculation window of PTW refers to the time window determined according to the calculation formula of PH, PTW_start and PTW_end mentioned above. Under normal circumstances, the eDRX cycle may overlap with the second time period, and the positions of PH and PTW_start may also be earlier than the end time of the second time period. If PH and PTW_start are determined only based on existing calculations, the terminal device may start monitoring PTW during periods without network coverage, which will generate unnecessary power consumption. To solve this problem, when the calculation window of PTW overlaps with the second time period, the actual window of PTW can be determined through adjustments.

[0289] As an example, the first configuration parameter may include various parameters for adjusting the PTW calculation window.

[0290] As an example, when the start position of the calculation window of the PTW is within the second time period, the terminal device skips the PTW or part of the PO within the PTW. The terminal device skips the PTW or PO, which means that the terminal device does not detect paging on the PTW or PO.

[0291] As an example, when the start position of the calculation window of the PTW is within the second time period, the network device skips the PTW or part of the PO in the PTW. The network device skips the PTW or PO, which means that the network device does not page the terminal device on the PTW or PO.

[0292] For example, if the calculated starting positions of PH and PTW are within the second time period, the terminal device (and the network) can skip PH and PTW, or at least skip some POs within the duration of the overlap between the second time period and PTW. Considering that the maximum length of PTW is only 4 superframes (for NB-IoT), once the terminal device skips some or all POs in the current PTW and the remaining paging fails to be sent to the terminal device, it waits for the PTW of the next eDRX cycle.

[0293] As an example, when the start position of the PTW calculation window is within the second time period, the start position of the actual PTW window is the sum of the start position of the calculation window and a first offset value. The first offset value can be determined based on the duration of the overlapping time period. In other words, when the PTW in the eDRX cycle partially overlaps with the second time period, the start position of the PTW (PTW_start) is adjusted so that the start position of the PTW in the eDRX cycle is aligned with or after the end time of the lack of network coverage.

[0294] The following is an exemplary description with reference to Figure 11. T2 represents the second time period. In Figure 11, the terminal device and the core network can calculate the PTW and the offset L (first offset value) between PTW_start and the end of the second time period. Through prediction, the terminal device can clearly know the duration of the second time period, the eDRX cycle, the location of the paging superframe, and related parameters of the PTW.

[0295] As shown in Figure 11, the starting position of the PTW calculation window for the next eDRX cycle, PTW_start, is delayed by the offset L. L may be greater than the paging superframe. In other words, the starting position of the actual PTW window is the position offset L from the starting position of the calculation window. Through this adjustment, during this eDRX cycle, the PTW is completely within the network coverage period, eliminating the need to waste resources initiating paging for unreachable terminal devices, and terminal devices will not lose important paging information. Therefore, the starting position of the actual PTW window, PTW_start′, can be expressed as: PTW_start′ = PTW_start + L.

[0296] For another example, the terminal device may adjust the relevant parameters of the PTW in each eDRX cycle, that is, the relevant parameters of the PTW in each eDRX cycle may change dynamically.

[0297] As an example, when the end position of the PTW calculation window is within the second time period, the end position of the actual PTW window is the difference between the end position of the calculation window and the second offset value. The second offset value can be determined based on the duration of the overlapping time period. In other words, when the PTW in the eDRX cycle partially overlaps with the second time period, the end position of the PTW (PTW_end) is adjusted so that the end position of the PTW in the eDRX cycle is aligned with or before the start time of the lack of network coverage.

[0298] The following is an exemplary explanation with reference to Figure 12, where T1 represents the first time period and T2 represents the second time period. In Figure 12, when the terminal device needs to enter the RRC idle state autonomously or according to the notification of the network device, it will send the first time information. As mentioned above, the terminal device can predict the time when it leaves the network coverage through the ephemeris parameters sent by the network device and its own location information. Furthermore, after the terminal device obtains the ephemeris parameters of other surrounding satellites from the first satellite, it can predict the time when it is covered by other satellites again, and thus estimate the time period when it has no network coverage, that is, the second time period. After calculating PTW and PTW_start, the terminal device and the core network can adjust the PTW_end within the eDRX cycle in combination with the relevant parameters of eDRX and the length of the second time period.

[0299] As shown in Figure 12, the terminal device estimates that after T1, it will enter a period without network coverage (the second time period). During the first eDRX cycle, the second time period partially overlaps with the duration of the PTW. The terminal device can determine the overlapping duration t (the second offset value) using PTW-related parameters and adjust PTW_end. Therefore, the end position of the actual PTW window, PTW_end′, can be expressed as: PTW_end′ = PTW_end-t.

[0300] As can be seen from FIG12 , since the end position of PTW is adjusted, the durations of the calculated window PTW1 and the actual window PTW2 are different.

[0301] As an example, when the calculation window of PTW within the eDRX cycle overlaps with the H-SFN at the end of the second time period, the terminal device can use offset_PH to adjust the PH to align it with the H-SFN at the end of the second time period.

[0302] It should be noted that although the second time period is a terminal device-specific parameter, the end times of the second time periods of multiple terminal devices may be very close. Therefore, in order to assign PTW_start to different terminal devices (for example, to assign suspended paging when restoring coverage), the core network may still need to configure different specific offsets for different terminal devices.

[0303] As an example, when the second time period overlaps with the calculation windows of the PTW in two adjacent eDRX cycles, the end position of the actual PTW window of the first eDRX cycle is no later than the start time of the second time period, and the start position of the actual PTW window of the second eDRX cycle is no earlier than the end time of the second time period. Considering that the granularity of the second time period may be large (e.g., minutes or hours), the second time period may overlap with the PTW in two adjacent eDRX cycles.

[0304] The following is an exemplary explanation with reference to Figure 13. The explanations of terms in Figures 11 and 12 will not be repeated. As shown in Figure 13, T2 partially overlaps with the PTW of both eDRX cycles. The overlapping duration of the PTW in the first eDRX cycle and the second time period is t, and the offset between PTW_start and the end time of the second time period in the second eDRX cycle is L. Since the adjustment of PTW_start or PTW_end occurs within its corresponding eDRX cycle, Figure 13 adjusts PTW_start and PTW_end at the same time to avoid the terminal device from performing paging detection during the period without network coverage, saving power consumption.

[0305] In some embodiments, the first configuration parameter may include an eDRX cycle. The eDRX cycle may be dynamically adjusted based on the duration of the second time period. As mentioned above, discontinuous coverage may occur periodically. The eDRX cycle configured by the core network may be similar to the period during which the network is not covered. Therefore, during the period without network coverage, the terminal device is likely to miss the PTW or part of the PTW each time, thereby affecting the paging effect. To solve this problem, the eDRX cycle can be dynamically configured and consistent with the time of the second time period. Optionally, the eDRX cycle can be dynamically configured based on the length of the second time period.

[0306] As an example, the eDRX cycle is proportional to the length of the second time period. If the second time period is longer, the eDRX cycle can be configured to be longer accordingly; if the second time period is shorter, the eDRX cycle can be configured to be shorter accordingly.

[0307] 9 , in step S930 , the core network sends the first configuration parameter to the network device. In step S940 , the terminal device receives the first configuration parameter forwarded by the network device.

[0308] The first configuration parameter may be used for the terminal device to perform a state transition. In some embodiments, the state transition performed by the terminal device may include a transition between any two of the following three states: an RRC active state, an RRC idle state, and a PSM state.

[0309] As can be seen from Figure 9, the core network can determine the first configuration parameters based on the first time information and / or the first recommended parameters of the terminal device, so as to avoid the terminal device from performing paging detection during the time when there is no network coverage, and avoid the network device from paging the terminal device during the time when the terminal device is unreachable, so as to save power consumption of the terminal device and the network device.

[0310] As previously mentioned, the first time information can be determined based on information related to multiple satellites associated with the terminal device. Furthermore, the information related to multiple satellites can be carried in one or more of the following information: SIB3, SIB31, and SIB32. Based on SIB3, SIB31, and SIB32, the terminal device can estimate whether the remaining coverage time of the cell or satellite is short.

[0311] In some embodiments, SIB32 can contain assistance information for up to four satellites. Due to the mobility and service characteristics of terminal devices, some information in SIB32 may not be relevant to the terminal device. For example, SIB32 may notify that a satellite will arrive within the next six hours, but the terminal device does not expect to transmit data within eight hours. In this case, the terminal device can request information about expected coverage availability after eight hours, and the network equipment can provide this satellite assistance information in a dedicated RRC.

[0312] In some embodiments, when the satellite information in SIB32 is not relevant to the terminal device, the terminal device may request the network device to provide satellite assistance information, which includes information related to satellites not included in the current SIB.

[0313] As an example, the terminal device may request the network to provide satellite assistance information via a dedicated RRC, which may include satellites that are not currently part of SIB32 or other SIBs.

[0314] In some embodiments, a terminal device can receive SIBs broadcast by different PLMNs. These broadcast SIBs may include SIB3, SIB31, and SIB32, among others. For example, in an NTN system with discontinuous coverage, a terminal device can obtain temporary parameters and coverage parameters from a currently or previously received SystemInformationBlockType32, SystemInformationBlockType31, or SystemInformationBlockType3. Based on the temporary parameters, the terminal device can determine whether it is outside of radio signal coverage. In other words, the terminal device can determine whether it is currently in a scenario without network coverage. If the terminal device is in a scenario without network coverage, the terminal device can, in response, deactivate access stratum functions to save power.

[0315] After the second time period, how the terminal device operates is also an issue that needs to be considered.

[0316] In some embodiments, after the second time period, the terminal device may receive data cached by the core network. For example, when the terminal device does not need to re-register with the PLMN network, the terminal device may receive data cached by the core network during the cache timer.

[0317] In some embodiments, after the second time period, the terminal device may enter the automatic network selection mode. For example, when the terminal device needs to re-register the PLMN network, the terminal device may enter the automatic network selection mode.

[0318] In some embodiments, when the terminal device is in a period of no network coverage or unreachable time, the AS layer of the terminal device is disconnected, but the NAS layer remains connected. In some scenarios, when the terminal device is in the PSM state in the second time period, although the terminal device no longer receives paging messages, the terminal device is still registered in the network. When the UE context retained by the NTN network and the PLMN network is consistent with the information of the terminal device re-establishing the RRC connection, the terminal device does not need to re-register with the network after waking up from sleep to send and receive data. In other words, although the terminal device is in an unreachable state, it is still registered in the PLMN network selected at the beginning.

[0319] In some embodiments, the UE context retained by the NTN network and the PLMN network may be inconsistent with the information for reestablishing the RRC connection of the terminal device, or the terminal device may need to reselect the PLMN network. In this scenario, the terminal device re-registers the PLMN.

[0320] As an example, the PLMN re-registration process is as follows: the terminal device first selects the most recently registered PLMN, then selects a high-priority PLMN service, and then selects a PLMN from the list of equivalent PLMNs (EPLMN) and attempts to register in the selected PLMN. It should be noted that the terminal device may delay attempts to obtain service on a higher-priority PLMN if it deactivates the access stratum due to discontinuous coverage.

[0321] As an example, a terminal device may be configured in automatic network selection mode. In automatic network selection mode in the NTN, the NB-IoT terminal device may select a sequence between a visited PLMN (VPLMN) and a HPLMN / equivalent home PLMN (EHPLMN).

[0322] As an example, the terminal device may register with a VPLMN and obtain services on the VPLMN.

[0323] As an example, the terminal device may start a timer according to the configured automatic network selection mode to periodically attempt to obtain service on the HPLMN or EHPLMN. When the access layer of the terminal device is deactivated due to discontinuous coverage in the NTN, the behavior of periodically attempting to access the HPLMN or EHPLMN with a higher priority needs to be redefined.

[0324] For ease of understanding, the following uses the NTN system core network as an example, and illustrates the method for the terminal device and the PLMN to negotiate energy-saving configuration during periods without network coverage, with reference to Figures 14 and 15. The dotted line in the figure represents a possible embodiment.

[0325] Figures 14 and 15 are written from the perspective of the interaction between the terminal device, NTN, and PLMN. In Figure 14, the PLMN sets timer T2 to buffer data to be sent. In Figure 15, the PLMN does not set a timer.

[0326] 14 , in step S1401 , the terminal device enters an automatic network selection mode.

[0327] In step S1402, the terminal device completes PLMN registration. After the terminal device successfully selects the PLMN, the registration is completed and the normal communication process is carried out.

[0328] In step S1403 , the NTN system sends SIB3 , SIB31 , and SIB32 via broadcast.

[0329] In step S1404, the terminal device establishes a communication connection with the NTN system. The terminal device can obtain the ephemeris parameters of the current satellite covering it and the ephemeris parameters of several neighboring satellites based on the broadcast.

[0330] In step S1405, the terminal device predicts the out-of-coverage time. The out-of-coverage time information is the first time period and the second time period associated with the first time information. The terminal device can predict and estimate based on its current location information or the network device triggering the terminal device.

[0331] In step S1406, the terminal device reports the first time information to the NTN network. The terminal device may report the coverage information via a dedicated RRC signaling message and send it to the NTN network.

[0332] In step S1407, the NTN network reports the first time information to the PLMN network. Based on the first time information, the PLMN network can determine that the terminal device is about to leave the network coverage area after time T1.

[0333] In step S1408, the terminal device reports the first recommended parameters to the NTN network. The terminal device can report the recommended DRX, eDRX, PSM and other parameters to the core network based on its service type, thereby negotiating with the AMF / MME to support the configuration of discontinuous coverage.

[0334] In step S1409, the NTN network reports the first recommended parameter to the PLMN network.

[0335] In step S1410, the PLMN network determines first configuration parameters and sets timer T2. Based on the first time information and the first recommended parameters, the PLMN network may update and set information for each DRX or eDRX cycle, and update timer information such as T3324 and T3412. Timer T2 is a buffer timer. The first configuration parameters may include configuration parameters such as the periodic TAU timer, DRX, eDRX, and PSM modes. For example, after comprehensive consideration, the AMF / MME provides the timer configuration to the terminal device.

[0336] In steps S1411 and S1412, the PLMN network sends the first configuration parameter to the NTN network, and the NTN network sends the first configuration parameter to the terminal device. The terminal device and the NTN network can calculate the PTW parameters in each eDRX cycle based on this information.

[0337] In step S1413, the terminal device enters the DRX and eDRX cycles.

[0338] In step S1414, the terminal device enters a no-network coverage scenario. During a first time period (T1), the terminal device may enter an RRC idle state autonomously or according to instructions. After T1, the terminal device may enter a no-network coverage scenario according to a predicted time.

[0339] In step S1415, the PLMN network starts timer T2 to buffer data.

[0340] In step S1416, the terminal device enters the network coverage scenario after the second time period (T2).

[0341] In step S1417, the PLMN network determines that the timer T2 expires.

[0342] In steps S1418 and S1419, the PLMN network sends the buffered data to the NTN network, and the NTN network forwards it to the terminal device.

[0343] Unlike Figure 14, the PLMN in Figure 15 does not set the timer T2, and the terminal device re-registers the PLMN after entering a state without network coverage. For the sake of brevity, the process explanation in Figure 14 will not be repeated in Figure 15.

[0344] Referring to FIG. 15 , steps S1501 to S1509 and steps S1511 to S1514 are not described again in detail.

[0345] In step S1510, the PLMN network only determines the first configuration parameter and does not set a timer. The first recommended parameter of the terminal device can enable negotiation between the terminal device and the core network regarding energy-saving configuration.

[0346] In step S1515, the terminal device enters the automatic network selection mode.

[0347] The method embodiment of the present application is described in detail above in conjunction with Figures 1 to 15. The device embodiment of the present application is described in detail below in conjunction with Figures 16 to 18. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for portions not described in detail, reference can be made to the above method embodiment.

[0348] FIG16 is a schematic block diagram of an apparatus for wireless communication according to an embodiment of the present application. The apparatus 1600 may be any terminal device described above. The apparatus 1600 shown in FIG16 includes a determining unit 1610 and a first executing unit 1620.

[0349] The determining unit 1610 may be configured to determine the first time information.

[0350] The first execution unit 1620 can be used to execute a transition from a first state to a second state based on the first time information; wherein the first time information is related to a first time period and / or a second time period, the first time period is a time period from the current moment to the starting moment when the terminal device enters a state without network coverage, and the second time period is a duration period without network coverage.

[0351] Optionally, the first state is an RRC idle state or a PSM state, and the first time information also includes a third time period in which the first service cell provides service to the terminal device, and the length of the third time period is used by the terminal device to determine whether to establish an RRC connection with the first service cell.

[0352] Optionally, the first state is an RRC active state, and the second state is an RRC idle state. The apparatus 1600 further includes a first sending unit configured to send first time information to the network device. A first receiving unit configured to receive first indication information sent by the network device, the first indication information including a transition timing of the terminal device from the RRC active state to the RRC idle state.

[0353] Optionally, the first state is the RRC activation state, and the second state is the RRC idle state. The device 1600 also includes: a processing unit, which can be used to start a first timer when sending the first time information, and the first timer is used by the terminal device to determine the transition timing from the RRC activation state to the RRC idle state.

[0354] Optionally, the device 1600 also includes a second sending unit, which can be used to send second indication information to the network device, and the second indication information indicates that the RRC idle state is the preferred state; the first execution unit 1620 is also used to convert from the RRC active state to the RRC idle state when the first timer expires.

[0355] Optionally, the conversion timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

[0356] Optionally, the conversion timing is determined according to a first factor δ(x, y), where x is related to the service type, y is related to the service priority, and 0<δ(x, y)≤1.

[0357] Optionally, the fourth time period between the conversion opportunity and the current moment is the product of the first time period and a second factor, where the second factor is greater than 0 and less than 1.

[0358] Optionally, the first state is a PSM state, and the determining unit is further configured to determine a time to be awakened based on a first cycle; wherein the first cycle is determined according to a first time period and a second time period.

[0359] Optionally, the terminal device is located in the service area of ​​the first satellite in the NTN at the current moment.

[0360] Optionally, the first time information is related to one or more of the following information: location information of the terminal device; relative location information between the terminal device and the first satellite; and related information of multiple satellites related to the terminal device; wherein the multiple satellites include the first satellite, and the related information of the multiple satellites includes at least one of the ephemeris information of multiple satellites, the location information of multiple satellites, the beam information of multiple satellites, and the time information of multiple satellites providing services to the terminal device.

[0361] Optionally, the relative position information includes an elevation angle of the terminal device relative to the first satellite, and / or a distance between the terminal device and an edge of the service area.

[0362] Optionally, the apparatus 1600 further includes a third sending unit, configured to send the first time information when the system information block includes beam information of any satellite among the multiple satellites.

[0363] Optionally, the first satellite is one of multiple satellites associated with the terminal device, and the multiple satellites also include one or more satellites other than the first satellite. The first time period is determined based on a first duration and a second duration. The first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when one or more satellites start to provide services to the terminal device.

[0364] Optionally, the device 1600 also includes a second execution unit, which is used to execute switching from the first satellite to the second satellite corresponding to the second duration according to the first condition when the first duration is greater than or equal to the second duration; the first execution unit 1620 is also used to convert from the RRC active state to the RRC idle state when the first duration is less than the second duration.

[0365] Optionally, the first condition is related to a switching condition for the terminal device to perform satellite switching and / or a service requirement of the terminal device.

[0366] Optionally, the first time information is carried in one or more of the following information: auxiliary information of the terminal device, a downlink channel quality report, and an access layer release auxiliary indication.

[0367] Optionally, the first execution unit 1620 is also used to convert from the RRC active state to the RRC idle state after triggering the wireless link failure N times when the actual time when the terminal device enters the state without network coverage is earlier than the time indicated by the first time information, where N is a natural number greater than or equal to 1.

[0368] FIG17 is a schematic block diagram of another apparatus for wireless communication according to an embodiment of the present application. The apparatus 1700 may be any of the network devices described above. The apparatus 1700 shown in FIG17 includes a determining unit 1710 and an instructing unit 1720.

[0369] The determining unit 1710 may be configured to determine the first time information.

[0370] The indication unit 1720 can be used to instruct the terminal device to perform a transition from a first state to a second state based on the first time information; wherein the first time information is related to a first time period and / or a second time period, the first time period is the time period from the current moment to the starting moment when the terminal device enters a state without network coverage, and the second time period is the duration period of the state without network coverage.

[0371] Optionally, the first state is an RRC idle state or a PSM state, and the first time information also includes a third time period in which the first service cell provides service to the terminal device, and the length of the third time period is used by the terminal device to determine whether to establish an RRC connection with the first service cell.

[0372] Optionally, the first state is the RRC activated state, and the second state is the RRC idle state. The device 1700 also includes a first receiving unit, which can be used to receive first time information sent by the terminal device; a sending unit, which can be used to send first indication information to the terminal device, and the first indication information includes the transition timing of the terminal device from the RRC activated state to the RRC idle state.

[0373] Optionally, the first state is the RRC activation state, and the second state is the RRC idle state. The device 1700 also includes a second receiving unit, which can be used to receive second indication information sent by the terminal device, and the second indication information indicates that the RRC idle state is the preferred state. The second indication information is used by the terminal device to determine the transition timing from the RRC activation state to the RRC idle state according to the first timer.

[0374] Optionally, the conversion timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

[0375] Optionally, the conversion timing is determined according to a first factor δ(x, y), where x is related to the service type, y is related to the service priority, and 0<δ(x, y)≤1.

[0376] Optionally, the fourth time period between the conversion opportunity and the current moment is the product of the first time period and a second factor, where the second factor is greater than 0 and less than 1.

[0377] Optionally, the network device includes a first satellite in the NTN, and the terminal device is located in a service area of ​​the first satellite at a current moment.

[0378] Optionally, the first time information is related to one or more of the following information: location information of the terminal device; relative location information between the terminal device and the first satellite; and related information of multiple satellites related to the terminal device; wherein the multiple satellites include the first satellite, and the related information of the multiple satellites includes at least one of the ephemeris information of multiple satellites, the location information of multiple satellites, the beam information of multiple satellites, and the time information of multiple satellites providing services to the terminal device.

[0379] Optionally, the relative position information includes an elevation angle of the terminal device relative to the first satellite, and / or a distance between the terminal device and an edge of the service area.

[0380] Optionally, the apparatus 1700 further includes a third receiving unit, configured to receive the first time information when the system information block includes beam information of any satellite among the multiple satellites.

[0381] Optionally, the first satellite is one of multiple satellites associated with the terminal device, and the multiple satellites also include one or more satellites other than the first satellite. The first time period is determined based on a first duration and a second duration. The first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when one or more satellites start to provide services to the terminal device.

[0382] Optionally, the first time information is carried in one or more of the following information: auxiliary information of the terminal device, a downlink channel quality report, and an access layer release auxiliary indication.

[0383] Figure 18 shows a schematic block diagram of a communication device according to an embodiment of the present application. The dashed lines in Figure 18 indicate that the unit or module is optional. Device 1800 can be used to implement the method described in the above method embodiment. Device 1800 can be a chip, a terminal device, or a network device.

[0384] The device 1800 may include one or more processors 1810. The processor 1810 may support the device 1800 to implement the method described in the method embodiment above. The processor 1810 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0385] The apparatus 1800 may further include one or more memories 1820. The memories 1820 store programs that can be executed by the processor 1810, causing the processor 1810 to perform the methods described in the above method embodiments. The memories 1820 may be independent of the processor 1810 or integrated into the processor 1810.

[0386] The apparatus 1800 may further include a transceiver 1830. The processor 1810 may communicate with other devices or chips via the transceiver 1830. For example, the processor 1810 may transmit and receive data with other devices or chips via the transceiver 1830.

[0387] The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal device or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal device or network device in each embodiment of the present application.

[0388] The computer-readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state drive (SSD)).

[0389] The present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal device or network device provided in the present application, and the program causes a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0390] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part 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, the process or function described in the embodiment of the present application is generated in whole or in part. 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 wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0391] The present application also provides a computer program that can be applied to a terminal device or network device provided in the present application, and enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0392] The terms "system" and "network" in this application may be used interchangeably. In addition, the terms used in this application are only used to explain the specific embodiments of this application and are not intended to limit this application. The terms "first," "second," "third," and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

[0393] In the embodiments of this application, the term "indication" may refer to a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" may refer to a direct indication of B, e.g., B can obtain information through A; it may refer to an indirect indication of B, e.g., A indicates C, e.g., B can obtain information through C; or it may refer to an association between A and B.

[0394] In the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and indication, configuration and configuration, etc.

[0395] In the embodiments of the present application, "pre-definition" or "pre-configuration" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., including a terminal device and a network device). The present application does not limit the specific implementation method. For example, pre-definition may refer to a definition in a protocol.

[0396] In the embodiments of the present application, the "protocol" may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, a NR protocol, and related protocols used in future communication systems, and this application does not limit this.

[0397] In the embodiments of the present application, determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0398] In the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0399] In the embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0400] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0401] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0402] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0403] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for wireless communication, characterized in that, including: The terminal device determines first time information; Based on the first time information, the terminal device performs a transition from a first state to a second state; Wherein, the first time information is related to a first time period and / or a second time period, the first time period is the time period from the current moment to the starting moment when the terminal device enters a network coverage-free area, and the second time period is the duration of the network coverage-free period.

2. The method according to claim 1, characterized in that, The first state is the Radio Resource Control (RRC) idle state or the Power Saving Mode (PSM) state. The first time information further includes a third time period during which the first serving cell provides services to the terminal device, and the duration of the third time period is used by the terminal device to determine whether to establish an RRC connection with the first serving cell.

3. The method according to claim 1, wherein The first state is the RRC active state, and the second state is the RRC idle state. The method further includes: The terminal device sends the first time information to the network device; The terminal device receives first indication information sent by the network device, and the first indication information includes the transition timing for the terminal device to transition from the RRC active state to the RRC idle state.

4. The method according to claim 1, wherein The first state is the RRC active state, and the second state is the RRC idle state. The method further includes: The terminal device starts a first timer when sending the first time information, and the first timer is used by the terminal device to determine the transition timing from the RRC active state to the RRC idle state.

5. The method according to claim 4, characterized in that, The method further includes: The terminal device sends second indication information to the network device, and the second indication information indicates that the RRC idle state is the preferred state; When the first timer expires, the terminal device transitions from the RRC active state to the RRC idle state.

6. The method according to claim 3 or 4, characterized in that The transition timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

7. The method according to claim 6, wherein The transition timing is determined according to a first factor δ(x, y), where x is related to the service type and y is related to the service priority, and 0 < δ(x, y) ≤ 1.

8. The method according to claim 6, wherein The fourth time period between the transition timing and the current moment is the product of the first time period and a second factor, and the second factor is greater than 0 and less than 1.

9. The method according to claim 1, wherein The first state is the PSM state. The method further includes: The terminal device determines the wake-up timing based on a first period; Wherein, the first period is determined according to the first time period and the second time period.

10. The method according to any one of claims 1-9, characterized in that, The terminal device is within the service area of the first satellite in the Non-Terrestrial Network (NTN) at the current moment.

11. The method according to claim 10, characterized in that The first time information is related to one or more of the following information: The location information of the terminal device; The relative position information between the terminal device and the first satellite; and The relevant information of multiple satellites related to the terminal device; Among them, the multiple satellites include the first satellite, and the relevant information of the multiple satellites includes at least one of the ephemeris information of the multiple satellites, the position information of the multiple satellites, the beam information of the multiple satellites, and the time information for the multiple satellites to provide services for the terminal device.

12. The method according to claim 11, wherein The relative position information includes the elevation angle of the terminal device relative to the first satellite, and / or the distance between the terminal device and the edge of the service area.

13. The method according to claim 11, characterized in that, The method further includes: When the system information block includes the beam information of any one of the multiple satellites, the terminal device sends the first time information.

14. The method according to any one of claims 10 to 13, characterized in that, The first satellite is one of the multiple satellites related to the terminal device. The multiple satellites further include one or more satellites other than the first satellite. The first time period is determined according to a first duration and a second duration. The first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when the one or more satellites start to provide services for the terminal device respectively.

15. The method according to claim 14, wherein The method further includes: When the first duration is greater than or equal to the second duration, the terminal device performs a handover from the first satellite to the second satellite corresponding to the second duration according to a first condition; When the first duration is less than the second duration, the terminal device converts from the RRC active state to the RRC idle state.

16. The method according to claim 15, wherein The first condition is related to the handover condition for the terminal device to perform satellite handover and / or the service requirements of the terminal device.

17. The method according to any one of claims 1-16, characterized in that, The first time information is carried in one or more of the following: the auxiliary information of the terminal device, the downlink channel quality report, and the access stratum release assistance indication.

18. The method according to any one of claims 1-17, characterized in that, The method further includes: When the actual time when the terminal device enters the area without network coverage is earlier than the time indicated by the first time information, the terminal device converts from the RRC active state to the RRC idle state after triggering a radio link failure N times, where N is a natural number greater than or equal to 1.

19. A method for wireless communication, characterized in that, Includes: The network device determines the first time information; Based on the first time information, the network device instructs the terminal device to perform a conversion from the first state to the second state; Among them, the first time information is related to a first time period and / or a second time period. The first time period is the time period from the current moment to the starting moment when the terminal device enters the area without network coverage, and the second time period is the duration of the area without network coverage.

20. The method according to claim 19, characterized in that, The first state is the radio resource control (RRC) idle state or the power saving mode (PSM) state. The first time information further includes a third time period for the first serving cell to provide services for the terminal device, and the duration of the third time period is used for the terminal device to determine whether to establish an RRC connection with the first serving cell.

21. The method according to claim 19, wherein The first state is the RRC active state, and the second state is the RRC idle state. The method further includes: The network device receives the first time information sent by the terminal device; The network device sends first indication information to the terminal device, where the first indication information includes the transition timing for the terminal device to transition from the RRC active state to the RRC idle state.

22. The method according to claim 19, wherein The first state is the RRC active state, and the second state is the RRC idle state. The method further includes: The network device receives second indication information sent by the terminal device, where the second indication information indicates that the RRC idle state is the preferred state, and the second indication information is used by the terminal device to determine the transition timing to transition from the RRC active state to the RRC idle state according to a first timer.

23. The method according to claim 21 or 22, characterized in that, The transition timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

24. The method according to claim 23, wherein The transition timing is determined according to a first factor δ(x,y), where x is related to the service type and y is related to the service priority, and 0 < δ(x,y) ≤ 1.

25. The method according to claim 23, wherein The fourth time period between the transition timing and the current moment is the product of the first time period and a second factor, and the second factor is greater than 0 and less than 1.

26. The method according to any one of claims 19-25, characterized in that, The network device includes a first satellite in a non-terrestrial network (NTN), and the terminal device is within the service area of the first satellite at the current moment.

27. The method according to claim 26, wherein The first time information is related to one or more of the following information: The location information of the terminal device; The relative position information between the terminal device and the first satellite; And The related information of multiple satellites related to the terminal device; Among them, the multiple satellites include the first satellite, and the related information of the multiple satellites includes at least one of the ephemeris information of the multiple satellites, the location information of the multiple satellites, the beam information of the multiple satellites, and the time information for the multiple satellites to provide services to the terminal device.

28. The method according to claim 27, wherein The relative position information includes the elevation angle of the terminal device relative to the first satellite, and / or the distance between the terminal device and the edge of the service area.

29. The method according to claim 27, wherein The method further includes: When the system information block includes the beam information of any one of the multiple satellites, the network device receives the first time information.

30. The method according to any one of claims 26-29, characterized in that, The first satellite is one of the multiple satellites related to the terminal device, and the multiple satellites further include one or more satellites other than the first satellite. The first time period is determined according to a first duration and a second duration. The first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when the one or more satellites start to provide services to the terminal device.

31. The method according to any one of claims 19 - 30, characterized in that, The first time information is carried in one or more of the following information: the auxiliary information of the terminal device, the downlink channel quality report, and the access stratum release assistance indication.

32. A device for wireless communication, characterized in that, The device is a terminal device, and the device includes: A determination unit, configured to determine first time information; A first execution unit, configured to perform the transition from the first state to the second state based on the first time information; Wherein, the first time information is related to the first time period and / or the second time period. The first time period is the time period from the current moment to the starting moment when the terminal device enters the area without network coverage, and the second time period is the duration of the area without network coverage.

33. The device according to claim 32, characterized in that, The first state is the Radio Resource Control (RRC) idle state or the Power Saving Mode (PSM) state. The first time information further includes a third time period during which the first serving cell provides services to the terminal device, and the duration of the third time period is used by the terminal device to determine whether to establish an RRC connection with the first serving cell.

34. The device according to claim 32, wherein The first state is the RRC active state, and the second state is the RRC idle state. The apparatus further includes: A first sending unit, configured to send the first time information to a network device. A first receiving unit, configured to receive first indication information sent by the network device, where the first indication information includes the conversion timing for the terminal device to convert from the RRC active state to the RRC idle state.

35. The device according to claim 32, characterized in that, The first state is the RRC active state, and the second state is the RRC idle state. The apparatus further includes: A processing unit, configured to start a first timer when sending the first time information. The first timer is used by the terminal device to determine the conversion timing for converting from the RRC active state to the RRC idle state.

36. The device according to claim 35, characterized in that, The apparatus further includes: A second sending unit, configured to send second indication information to the network device, where the second indication information indicates that the RRC idle state is the preferred state. The first execution unit is further configured to convert from the RRC active state to the RRC idle state when the first timer expires.

37. The device according to claim 34 or 35, characterized in that, The conversion timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

38. The device according to claim 37, wherein The conversion timing is determined according to a first factor δ(x, y), where x is related to the service type and y is related to the service priority, and 0 < δ(x, y) ≤ 1.

39. The device according to claim 37, characterized in that, The fourth time period between the conversion timing and the current moment is the product of the first time period and a second factor, and the second factor is greater than 0 and less than 1.

40. The device according to claim 32, characterized in that, The first state is the PSM state. The determining unit is further configured to determine the wake-up timing based on a first period; wherein, the first period is determined according to the first time period and the second time period.

41. The device according to any one of claims 32-40, characterized in that, The terminal device is within the service area of the first satellite in a Non-Terrestrial Network (NTN) at the current moment.

42. The device according to claim 41, characterized in that, The first time information is related to one or more of the following information: The location information of the terminal device; The relative position information between the terminal device and the first satellite; And The relevant information of multiple satellites related to the terminal device; Wherein, the multiple satellites include the first satellite, and the relevant information of the multiple satellites includes at least one of the ephemeris information of the multiple satellites, the location information of the multiple satellites, the beam information of the multiple satellites, and the time information for the multiple satellites to provide services to the terminal device.

43. The device according to claim 42, characterized in that, The relative position information includes the elevation angle of the terminal device relative to the first satellite, and / or the distance between the terminal device and the edge of the service area.

44. The device according to claim 42, wherein, The device further includes: A third sending unit, configured to send the first time information when the system information block includes the beam information of any one of the multiple satellites.

45. The device according to any one of claims 41-44, characterized in that, The first satellite is one of the multiple satellites related to the terminal device, and the multiple satellites further include one or more satellites other than the first satellite. The first time period is determined according to a first duration and a second duration. The first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when the one or more satellites start to provide services to the terminal device respectively.

46. The device according to claim 45, characterized in that, The device further includes: A second execution unit, configured to perform a handover from the first satellite to the second satellite corresponding to the second duration according to a first condition when the first duration is greater than or equal to the second duration. The first execution unit is further configured to perform a transition from the RRC active state to the RRC idle state when the first duration is less than the second duration.

47. The device according to claim 46, characterized in that, The first condition is related to the handover condition for the terminal device to perform satellite handover and / or the service requirements of the terminal device.

48. The device according to any one of claims 32-47, characterized in that, The first time information is carried in one or more of the following information: the auxiliary information of the terminal device, the downlink channel quality report, and the access stratum release assistance indication.

49. The device according to any one of claims 32 - 48, characterized in that, The first execution unit is further configured to perform a transition from the RRC active state to the RRC idle state after triggering a radio link failure N times when the actual time when the terminal device enters a network coverage-free area is earlier than the time indicated by the first time information, where N is a natural number greater than or equal to 1.

50. A device for wireless communication, characterized in that, The device is a network device, and the device includes: A determination unit, configured to determine the first time information. An indication unit, configured to indicate the terminal device to perform a transition from a first state to a second state based on the first time information. Wherein, the first time information is related to a first time period and / or a second time period. The first time period is the time period from the current moment to the starting moment when the terminal device enters a network coverage-free area, and the second time period is the duration of the network coverage-free period.

51. The device according to claim 50, wherein, The first state is the radio resource control (RRC) idle state or the power saving mode (PSM) state. The first time information further includes a third time period during which the first serving cell provides services to the terminal device, and the duration of the third time period is used for the terminal device to determine whether to establish an RRC connection with the first serving cell.

52. The device according to claim 50, characterized in that, The first state is the RRC active state, the second state is the RRC idle state, and the device further includes: A first receiving unit, configured to receive the first time information sent by the terminal device. A sending unit, configured to send a first indication information to the terminal device, where the first indication information includes the transition timing for the terminal device to transition from the RRC active state to the RRC idle state.

53. The device according to claim 50, characterized in that, The first state is the RRC active state, the second state is the RRC idle state, and the device further includes: A second receiving unit, configured to receive second indication information sent by the terminal device, where the second indication information indicates that the RRC idle state is the preferred state, and the second indication information is used by the terminal device to determine a transition timing from the RRC active state to the RRC idle state according to a first timer.

54. The device according to claim 52 or 53, characterized in that, The transition timing is related to one or more of the following information: the service type of the terminal device, the service priority of the terminal device, and the downlink data of the network device.

55. The device according to claim 54, characterized in that, The transition timing is determined according to a first factor δ(x, y), where x is related to the service type and y is related to the service priority, and 0 < δ(x, y) ≤ 1.

56. The device according to claim 54, characterized in that, A fourth time period between the transition timing and the current moment is the product of the first time period and a second factor, and the second factor is greater than 0 and less than 1.

57. The device according to any one of claims 50-56, characterized in that, The network device includes a first satellite in a non-terrestrial network (NTN), and the terminal device is located within the service area of the first satellite at the current moment.

58. The device according to claim 57, characterized in that, The first time information is related to one or more of the following information: The location information of the terminal device; The relative position information between the terminal device and the first satellite; And The related information of multiple satellites related to the terminal device; Wherein, the multiple satellites include the first satellite, and the related information of the multiple satellites includes at least one of the ephemeris information of the multiple satellites, the position information of the multiple satellites, the beam information of the multiple satellites, and the time information for the multiple satellites to provide services to the terminal device.

59. The device according to claim 58, characterized in that, The relative position information includes the elevation angle of the terminal device relative to the first satellite, and / or the distance between the terminal device and the edge of the service area.

60. The device according to claim 58, wherein, The device further includes: A third receiving unit, configured to receive the first time information when the system information block includes the beam information of any one of the multiple satellites.

61. The device according to any one of claims 57 - 60, characterized in that, The first satellite is one of the multiple satellites related to the terminal device, the multiple satellites further include one or more satellites other than the first satellite, the first time period is determined according to a first duration and a second duration, the first duration is the duration between the current moment and the moment when the terminal device leaves the service area, and the second duration is the minimum value of one or more durations between the current moment and one or more moments when the one or more satellites start to provide services to the terminal device. The apparatus according to any one of claims 50-61, characterized in that The first time information is carried in one or more of the following information: the auxiliary information of the terminal device, the downlink channel quality report, and the access stratum release assistance indication.

63. A communication device, characterized in that, It includes a memory and a processor, the memory is used to store a program, and the processor is used to call the program in the memory to execute the method according to any one of claims 1-31.

64. A device, characterized in that, It includes a processor, configured to call a program from a memory to execute the method according to any one of claims 1-31.

65. A chip, characterized in that, It includes a processor for calling a program from a memory, such that a device installed with the chip executes the method according to any one of claims 1-31.

66. A computer-readable storage medium, characterized in that, A program is stored thereon, and the program causes a computer to execute the method according to any one of claims 1-31.

67. A computer program product, characterized in that, It includes a program, and the program causes a computer to execute the method according to any one of claims 1-31.

68. A computer program, characterized in that, The computer program causes a computer to execute the method according to any one of claims 1-31.

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