Power control

Abstract

The embodiment of the invention relates to a method, equipment and device for power control and a computer readable storage medium. In a method, a first device obtains a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite. The first device determines the transmission power based on the first path loss and a difference between the first path loss and the second path loss after switching from the source satellite to the target satellite.

Description

Technical Field

[0001] Various example embodiments of the present disclosure relate generally to the field of telecommunications, and in particular to methods, devices, apparatuses, and computer-readable storage media for power control. Background Art

[0002] Non-terrestrial communications can be used in a complementary manner to terrestrial deployments, where satellite connectivity can provide coverage beyond terrestrial deployments. In a non-terrestrial network (NTN) scenario with unchanged physical cell identity (ID), satellite switching occurs transparently to the user equipment (UE). The UE switches from the source satellite access node to the target satellite access node without performing layer 3 (L3) mobility and without changing the serving new radio (NR) NodeB (or gNB). Therefore, the path loss experienced by the UE when connected to the target satellite access node may change suddenly compared to the path loss in the source satellite. Because the UE does not perform L3 mobility, the UE does not reset the power control loop, which may cause the UE to rely on outdated path loss compensation to set the transmission power. Therefore, the UE may not be able to transmit with sufficient power, or may cause greater UL interference and higher power consumption of the UE.

[0003] For the changing physical cell ID (PCI) scenario, similar problems of power control in an unchanged PCI also exist. The sudden channel change may have an impact on the uplink control when resynchronizing with another satellite. Therefore, an improved power control scheme is necessary. Summary of the invention

[0004] In a first aspect of the present disclosure, a method at a first device is provided. In the method, the first device obtains at least a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and after switching from the source satellite to the target satellite, determines a transmission power based on the first path loss and the difference between the first path loss and the second path loss.

[0005] In a second aspect of the present disclosure, a method at a second device is provided. In the method, the second device determines that a handover from a source satellite to a target satellite is to be performed for a first device; and before the handover, information for power control of the first device is sent to the first device, the information including at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0006] In a third aspect of the present disclosure, a first device is provided. The first device includes: at least one processor; and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the first device at least: obtains a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and after switching from the source satellite to the target satellite, determines a transmission power based on the first path loss and the difference between the first path loss and the second path loss.

[0007] In a fourth aspect of the present disclosure, a second device is provided. The second device includes: at least one processor; and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the second device at least: determines that a switch from a source satellite to a target satellite is to be performed for a first device; and before the switch, sends information for power control of the first device to the first device, the information including at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0008] In a fifth aspect of the present disclosure, a first device is provided. The first device includes a component for obtaining a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and a component for determining a transmission power based on the first path loss and the difference between the first path loss and the second path loss after switching from the source satellite to the target satellite.

[0009] In a sixth aspect of the present disclosure, a second device is provided. The second device includes: a component for determining that a handover from a source satellite to a target satellite is to be performed for a first device; and a component for sending information for power control of the first device to the first device before the handover, the information including at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0010] In a seventh aspect of the present disclosure, a computer-readable medium is provided, wherein the computer-readable medium includes instructions stored thereon, and the instructions are used to cause a device to at least execute the method according to the first aspect or the second aspect.

[0011] It should be understood that the contents described in the Summary of the Invention are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0013] Figure 1 An example communication environment is shown in which example embodiments of the present disclosure can be implemented;

[0014] Figure 2 A signaling diagram illustrating an example communication process in a communication environment according to some example embodiments of the present disclosure;

[0015] Figure 3 An example process of power control according to some example embodiments of the present disclosure is shown;

[0016] Figure 4 A flow chart illustrating an example method of power control according to some example embodiments of the present disclosure;

[0017] Figure 5 A flowchart illustrating another example method of power control according to some example embodiments of the present disclosure;

[0018] Figure 6 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure; and

[0019] Figure 7 A block diagram of an example computer-readable medium is shown according to some example embodiments of the present disclosure.

[0020] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0021] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only for the purpose of illustration and to help those skilled in the art understand and implement the present disclosure without implying any limitation on the scope of the present disclosure. In addition to the methods described below, the embodiments described herein can be implemented in various ways.

[0022] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0023] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it is considered within the knowledge of those skilled in the art that such feature, structure, or characteristic may be affected in conjunction with other embodiments.

[0024] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0025] As used herein, “at least one of: ” and “at least one of ” and similar expressions, where a list of two or more elements is connected by “and” or “or”, refer to at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0026] As used herein, unless explicitly stated otherwise, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs, but may include one or more intermediate steps.

[0027] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that when used herein, the terms "comprises", "comprising", "has", "having", "includes", and / or "including" specify the presence of features, elements, and / or parts, etc., but do not exclude the presence or addition of one or more other features, elements, parts, and / or combinations thereof.

[0028] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware circuit implementations only (such as implementations in analog and / or digital circuitry only) and (b) a combination of hardware circuitry and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuits and software / firmware and (ii) a hardware processor and software (including a digital signal processor), any portion of software and memory, which work together to enable a device (such as a mobile phone or server) to perform various functions, and (c) a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, which requires software (e.g. firmware) to operate, but the software may be absent when not required for operation.

[0029] This definition of circuitry applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to a particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0030] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), sixth generation (6G) communication protocol and / or any other protocol currently known or developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there are of course future types of communication technologies and systems that can implement the present disclosure. It should not be considered that the scope of the present disclosure is limited to the above-mentioned system.

[0031] As used herein, the term "network device" refers to the following node in a communication network, via which a terminal device accesses the network and receives services from it. A network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a repeater, an integrated access and backhaul (IAB) node, a low-power node such as a femto station, a micro station, a non-terrestrial network (NTN) or non-terrestrial network equipment, such as satellite network equipment, a low earth orbit (LEO) satellite and a geosynchronous orbit (GEO) satellite, an aircraft network device, etc., depending on the terminology and technology applied. In some example embodiments, a radio access network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) at an IAB donor node. An IAB node includes a mobile terminal (IAB-MT) portion that behaves similarly to a UE toward a parent node, and a DU portion of an IAB node behaves similarly to a base station toward a next-hop IAB node.

[0032] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, the terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS) or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback facility, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded equipment (LEE), a laptop mounted equipment (LME), a USB dongle, a smart device, a wireless user terminal equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automatic processing chain environments), consumer electronic devices, equipment operating on commercial and / or industrial wireless networks, etc. The terminal device may also correspond to the mobile terminal (MT) part of an IAB node (eg, a relay node).In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0033] As used herein, the terms "resource", "transmission resource", "resource block", "physical resource block" (PRB), "uplink resource" or "downlink resource" may refer to any resource used to perform communication, for example, communication between a terminal device and a network device, such as resources in the time domain, resources in the frequency domain, resources in the spatial domain, resources in the code domain, or any other resource supporting communication. In the following, unless explicitly stated, resources in the frequency domain and the time domain will be used as examples of transmission resources for describing some example embodiments of the present disclosure. It should be noted that the example embodiments of the present disclosure are also applicable to other resources in other domains.

[0034] The 3rd Generation Partnership Project (3GPP) has defined and completed work items for Release 17 (Rel-17) on NTN and Release 18 (Rel-18) on NTN performance enhancements. One of the goals of Rel-18 NR NTN is to continue to enhance NTN-NTN and NTN-TN mobility and service continuity. The work items consider existing methods from NR TN and Rel-17 NR NTN as a baseline for further enhancements, including specifying NTN-NTN handover enhancements for radio resource control (RRC)_CONNECTED UEs in quasi-geo-fixed cells and geo-mobile cells to reduce signaling overhead.

[0035] In Rel-17 NTN, cells originating from different satellites are associated with different PCIs. Fixed UEs may experience continuous L3 mobility when the serving satellite moves out of coverage and a new satellite takes over coverage of a geographical area. A constant PCI solution may avoid the need for L3 mobility and may reduce signaling overhead considering the large number of UEs served within an NTN cell.

[0036] Some agreements related to the unchanged PCI solution were discussed. The following were agreed upon: In case of quasi-geo-fixed cells, satellite handover without PCI change (no L3 mobility required) is supported for hard satellite handover in the same synchronization signal block (SSB) frequency and same gNB.

[0037] In a hard handover unchanged PCI scenario (i.e., no handover), the UE needs to know when the UE attempts to resynchronize (e.g., whether a new "t-Start" / t-gap is needed, or whether t-service can be reused when the gap is very short / zero (i.e., no other IE)). When a hard handover occurs, some new parameters such as timing advance (TA) and ephemeris are applied during the UE resynchronization to the new satellite.

[0038] In Rel-18, the focus is on transparent architecture and there are cases where cells are provided by the same gNB, i.e. the same cell with fixed PCI is provided by the same gNB. In this case, only the satellite node changes. The transparent architecture can also work with different gNBs and potentially even for regeneration scenarios.

[0039] Considering that the location of the target satellite compared to the source satellite may be different, the radio channels including the path losses associated with the source and target satellites may be different, which may affect measurement related control functions such as radio link monitoring and uplink power control.

[0040] Uplink power control plays an important role in mobile communication systems. By controlling the transmit power of different uplink physical channels and signals, it is ensured that the uplink channels are received with appropriate power to maintain the link quality corresponding to the required Quality of Service (QoS). To this end, power control needs to adapt to the characteristics of the radio transmission channel.

[0041] The power control scheme in LTE and NR uses a combination of open-loop and closed-loop control for the Physical Uplink Shared Channel (PUSCH) as follows: P = P0 + α · PL + delta (1)

[0042] Open-loop power control (P0+α·PL) sets a rough operating point for the transmit power spectral density (PSD) based on path loss measurements. Closed-loop power control (represented by delta) can adjust the transmit power around the open-loop operating point to quickly adapt to channel conditions and interference levels. In open-loop power control for PUSCH and sounding reference signal (SRS), path loss is compensated via the path loss compensation factor alpha (i.e., α), which not only ensures reliable reception of the uplink channel, but also controls interference to other cells.

[0043] When satellite switching occurs, the path loss between the UE and the serving satellite changes suddenly. Therefore, the transmit power obtained based on the previous measurement is not accurate. For example, if the path loss becomes larger, the transmit power obtained based on the previous measurement cannot compensate for the large path loss and ensure the expected level of received power. If the path loss becomes smaller, the transmit power based on the previous measurement is large, which may cause greater interference to other cells. Therefore, it is worth studying how to set the appropriate transmission power when the serving satellite switches with an unchanged PCI.

[0044] In addition, similar concepts for changed PCI and unchanged PCI are discussed, which can solve the problem of unchanged PCI not supported by Rel 17 terminals. In the case of changed PCI, the following features can be supported: there is no handover (for Rel-18 UEs); the cell configuration remains the same (except for system information block 19 (SIB19)); but the PCI changes.

[0045] Therefore, similar issues regarding power control exist in unchanged PCI for changing PCI.Sudden channel changes should have an impact on uplink control when resynchronizing with another satellite, and improved uplink power control solutions should be considered.

[0046] Example embodiments of the present disclosure propose a power control scheme for satellite switching. With the scheme, a first device such as a UE determines the transmission power after satellite switching based on the difference between the path losses associated with the source satellite and the target satellite obtained. The proposed scheme can be used in both unchanged PCI scenarios and changed PCI scenarios.

[0047] In this manner, power control based on the difference between path losses associated with the source satellite and the target satellite may avoid failed transmissions, reduce inter-cell interference, and reduce power consumption of the first device.

[0048] Figure 1An example communication environment 100 is shown in which example embodiments of the present disclosure can be implemented. In the communication environment 100, first devices 110-1 and 110-2 (individually or collectively referred to as first devices 110) and second device 120 can communicate with each other through a source satellite 130 or a target satellite 140. In some example embodiments, first device 110 may be a terminal device, such as a UE. Second device 120 may be a network device such as a gNB.

[0049] The link between the second device 120 and the satellite 130 or the satellite 140 may be referred to as a feeder link, and the link between the satellite 130 or the satellite 140 and the first device 110 may be referred to as an access link.

[0050] In some example embodiments, if the first device 110 is a terminal device and the second device 120 is a network device, the link from the second device 120 to the first device 110 is referred to as a downlink (DL), and the link from the first device 110 to the second device 120 is referred to as an uplink (UL). In the DL, the second device 120 is a transmitting (TX) device (or transmitter), and the first device 110 is a receiving (RX) device (or receiver). In the UL, the first device 110 is a TX device (or transmitter), and the second device 120 is an RX device (or receiver).

[0051] Hereinafter, for the purpose of illustration, some example embodiments are described in the case where the first device 110 operates as a terminal device and the second device 120 operates as a network device. However, in some example embodiments, the operations described in conjunction with the terminal device may be implemented at a network device or other device, and the operations described in conjunction with the network device may be implemented at a terminal device or another device.

[0052] The communication in the communication environment 100 can be implemented according to any appropriate communication protocol, including but not limited to cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), etc., wireless local area network communication protocols such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocol currently known or developed in the future. In addition, the communication can use any appropriate wireless communication technology, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiple access (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM) and / or any other technology currently known or developed in the future.

[0053] It should be understood that Figure 1The number of devices and their connections shown in are for illustration purposes only and do not imply any limitation.Communication environment 100 may include any suitable number of devices configured to implement example embodiments of the present disclosure.

[0054] In some example embodiments, satellite switching may occur in some cases. For example, it may be assumed that the first device 110-1 is stationary or mobile and is being served by the source satellite 130 (i.e., the serving satellite is currently the source satellite 130). As the source satellite 130 moves away from the first device 110-1, for example, in the moving direction 180, and the target satellite 140 becomes closer, then a satellite switching will occur at this time. The network (e.g., the second device 120) may instruct the first device 110 when a satellite switching will occur and how to perform resynchronization to the new cell. Once the target satellite 140 takes over, the first device 110 may perform a DL / UL synchronization operation to adjust the time and frequency.

[0055] In some example embodiments, for a quasi-Earth Fixed Cell (EFC) scenario, the geographic area 150 is associated with a physical cell ID (PCI) and the second device 120. For a constant PCI scenario, the second device 120 can provide service to the same coverage (e.g., geographic area 150) while connected to different satellites (e.g., source satellite 130 and target satellite 140), and the PCI can remain unchanged after the satellite handover. In this case, a non-terrestrial network (NTN) cell is deployed as an EFC because the coverage area of ​​the cell has not changed. The second device 120 instructs the first device 110 when and how to perform DL and UL synchronization after the satellite handover, or an interruption gap can be accepted for the first device 110 to detect the new timing and adapt to it. Because the PCI, the second device 120, the security key, and the SSB frequency remain the same, the satellite handover can be mostly transparent to the first device 110.

[0056] When the satellite switching occurs, the service satellite changes from the source satellite 130 to the target satellite 140. For the first device 110-1, the path loss between the first device 110-1 and the service satellite may suddenly become larger. For example, the communication path 160 between the first device 110-1 and the source satellite 130 may be changed to a longer communication path 170 between the first device 110-1 and the target satellite 140, and the path loss becomes larger due to the increase in the path length. Therefore, the transmission power obtained according to the previous measurement may not compensate for the larger path loss. For the first device 110-2, the path loss between the first device 110-2 and the service satellite may become smaller. For example, the communication path loss between the first device 110-2 and the source satellite 130 may be changed to a shorter communication path 175 between the first device 110-2 and the target satellite 140. Therefore, the transmission power based on the previous measurement may be larger, which may cause greater interference to the neighboring cells.

[0057] For the changed PCI scenario, no handover may occur and the cell configuration may remain the same. Therefore, for the changed PCI scenario, similar issues exist regarding power control in the unchanged PCI scenario. When the first device 110 resynchronizes from the source satellite 130 to the target satellite 140, the sudden channel change may affect the power control of the first device 110.

[0058] According to an embodiment of the present disclosure, for both the unchanged PCI case and the changed PCI case, the transmission power is determined by the first device 110 based on the difference between the first path loss associated with the source satellite 130 and the second path loss associated with the target satellite 140. By using an improved UL power control scheme that sets an appropriate transmission power when the serving satellite is switched, inter-cell interference and power consumption of the first device 110 can be reduced, and failed transmissions can be avoided.

[0059] The following will refer to Figure 2 and Figure 3 Some example implementations are discussed.

[0060] Figure 2 A signaling diagram is shown of an example communication process 200 between a first device 110 and a second device 120 in a communication environment 100 according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 Process 200 is described.

[0061] like Figure 2As shown, the first device 110 may obtain (215) a difference between a first path loss associated with the source satellite 130 and a second path loss associated with the target satellite 140, also referred to as a path loss difference between the source satellite 130 and the target satellite 140. The path loss difference may be obtained when switching from the source satellite 130 to the target satellite 140.

[0062] In some example embodiments, the second device 120 may determine that a handover from the source satellite 130 to the target satellite 140 is to be performed for the first device 110. In some example embodiments, the second device 120 may send a first indication of the time of the handover to the first device 110. Thus, the first device 110 may receive the first indication of the time of the handover from the second device 120. For example, based on a parameter t-Service introduced in the SIB, the first device 110 may be informed when a satellite handover is to occur. The t-Service in the SIB may be interpreted by a Rel-18 UE in connected mode to be aware of the occurrence of a satellite change or a feeder link change.

[0063] In some example embodiments, second device 120 may send a second indication that the difference between the first path loss and the second path loss is enabled for power control to first device 110. Thus, first device 110 may receive a second indication that the difference between the first path loss and the second path loss is enabled for power control from second device 120. For example, second device 120 may indicate whether the proposed power control scheme is enabled for first device 110. If it is enabled, first device 110 may use the path loss difference between source satellite 130 and target satellite 140 for power control. In some example embodiments, the second indication may be sent from second device 120 to first device 110 via a SIB message or a radio resource control (RRC) message.

[0064] In some example embodiments, second device 120 may determine whether the proposed power control scheme is applied to first device 110 based on the cell size. For example, if the cell coverage is large, second device 120 may configure first device 110 to use the proposed power control scheme via RRC or SIB signaling. If the cell coverage is small, second device 120 will not be configured to use the proposed power control scheme, and a direct difference compared to the old power may be provided to first device 110 by turning off the power control command.

[0065] To obtain the path loss difference, the first device 110 may receive the difference from the second device 120, or may determine the difference itself. Figure 2As shown, before switching from the source satellite 130 to the target satellite 140, the second device 120 may send (205) information for power control of the first device 110 to the first device 110. The information may include a difference between a first path loss associated with the source satellite 130 and a second path loss associated with the target satellite 140. Therefore, the first device 110 may receive (210) the difference between the first path loss and the second path loss from the second device 120. For example, the second device 120 may estimate the path loss difference and provide it to the first device 110 together with the system information of the new cell before the interruption (e.g., satellite switching).

[0066] In some example embodiments, the difference between the first path loss and the second path loss may be sent from the second device 120 to the first device 110 via a SIB message prior to the handover. In some example embodiments, the difference between the first path loss and the second path loss may be sent via an RRC message prior to the handover. In some example embodiments, the difference between the first path loss and the second path loss may be sent via a message during a random access procedure with the target satellite.

[0067] Alternatively or additionally, the first device 110 may determine the difference between the first path loss and the second path loss by itself based on the ephemeris information of the source satellite and the target satellite, the position of the first device 110, and the path loss model. In some example embodiments, instead of the difference between the first path loss and the second path loss, the information provided by the second device 120 to the first device 110 for power control may include the ephemeris information of the source satellite and the target satellite. For example, the ephemeris information may be provided by the second device 120 before the satellite is switched. Thus, the first device 110 may obtain the ephemeris information of the source satellite 130 and the target satellite 140. The first device 110 may use any positioning method or algorithm to determine its own position. The scope of the present disclosure is not limited in this regard.

[0068] In some example embodiments, the path loss model may be predefined or configured by second device 120. For example, the configuration of the path loss model may be transmitted by second device 120, and first device 110 may receive the configuration from second device 120.

[0069] In some example embodiments, the path loss model may be a free space path loss model, etc. Taking the free space path loss model as an example, the first device 110 may calculate the distance and path loss from the source satellite 130 and the target satellite 140, respectively, according to the following equations: FSPL(d,f c )=32.45+20log 10 (f c )+20log 10(d) (2)

[0070] FSPL represents free space path loss (e.g., in dB), d represents the separation distance (e.g., in meters), and f c represents a frequency (eg, in GHz). Based on the above equation, the first device 110 may estimate a path loss difference between the source satellite 130 and the target satellite 140 .

[0071] In some example embodiments, first device 110 may determine (220) a transmission power based on a first path loss associated with source satellite 130 and a difference between the first path loss and the second path loss after switching from source satellite 130 to target satellite 140. For example, the transmission power may be determined using the following path loss: PL = PL0 + PL difference , (3) where PL0 represents the first path loss associated with the source satellite 130, and PL difference represents the path loss difference between the source satellite 130 and the target satellite 140.

[0072] In some example embodiments, the first PL associated with source satellite 130 may be derived by measurements of received reference signal received power (RSRP) and the reference signal power indicated from second device 120 to first device 110. The path loss may be calculated by the following equation: PL = Reference signal power – Filtered RSRP, (4) The reference signal power represents the reference signal power indicated by the second device 120, and the filtered RSRP represents a measurement of the RSRP obtained by the filtering operation.

[0073] Taking the power control for PUSCH as an example, the transmission power can be set based on the following equation after the time window: P(target satellite)=P(source satellite)+α·delta PL+delta, (5) Among them, P (target satellite) represents the transmission power for the target satellite 140, P (source satellite) represents the transmission power for the source satellite 130, α represents the path loss compensation factor, delta represents the power adjustment from the power off control command alone, and delta PL represents the path loss difference between the source satellite 130 and the target satellite 140.

[0074] It should be understood that the power control for PUSCH is only illustrative and not restrictive. The proposed power control scheme can be applied to other channels or signals, such as Physical Uplink Control Channel (PUCCH), Physical Random Access Channel (PRACH) and Sounding Reference Signal (SRS).

[0075] In some example embodiments, the transmission power is determined by the first device 110 in a time window after the switch based on the first path loss and the difference between the first path loss and the second path loss. The time window can be used to allow a certain amount of time to properly measure the new channel conditions. The time window can be counted by a window timer. In some example embodiments, the time window can be predefined or configured by the second device 120, and the configuration of the time window can be sent from the second device 120 to the first device 110.

[0076] In some example embodiments, after the time window, the first device 110 may determine the transmission power based on the measurement of the second path loss. For example, after the time window, the measurement of the second path loss is used instead of the path loss difference to determine the transmission power for power control.

[0077] In some example embodiments, after the switch, the first device 110 may discard measurements associated with the source satellite 130 and may record new measurements associated with the target satellite 140 to improve the estimation accuracy by averaging new values ​​of the channel with the target satellite 140. When appropriate measurements of the new channel conditions can be derived, the first device 110 may use the newly estimated path loss value (i.e., the measurement for the second path loss) to calculate the transmission power. In some embodiments, the first device 110 may generate a report related to the measurement for the second path loss and deliver it to the second device 120 after the satellite switch.

[0078] In some example embodiments, first device 110 may use transmission power to perform transmissions associated with at least one of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a physical random access channel (PRACH), or a sounding reference signal (SRS). Other channels and / or signals are also possible.

[0079] Figure 3 An example process 300 for power control for a PUSCH according to some example embodiments of the present disclosure is shown. In this example, the second device 120 may operate as a network device, and the first device 110 may operate as a terminal device.

[0080] like Figure 3As shown, in process 300 , at block 305 , the second device 120 may indicate that the proposed power control scheme is applied to the first device 110 , and the second device 120 may indicate when satellite switching occurs and the ephemeris information of the target satellite 140 .

[0081] If it is determined at block 307 that a satellite handoff has occurred, then at block 310 the first device 110 may discard measurements associated with the source satellite 130 and log new measurements to the target satellite 140 , and the first device 110 may start a window timer.

[0082] At block 313, it is determined whether the count-up window timer is less than a predetermined value T. If it is determined at block 313 that the window timer is less than the predetermined value T, then at block 315, the first device 110 may calculate a path loss difference between the source satellite 130 and the target satellite 140, and determine a UL transmission power for the PUSCH based on the following formula: P(target satellite)=P(source satellite)+alpha*Delta PL+delta.

[0083] If it is determined at block 313 that the window timer is not less than the predetermined value T, then at block 320, the first device 110 may calculate the window timer based on P=P0+α·P L +delta determines the UL transmission power for PUSCH.

[0084] It should be understood that Figure 3 The process 300 shown uses the power control of PUSCH as an example. Figure 3 The formula shown is used for the transmission power of PUSCH. For other channels and signals, the formula will be different, and reference may be made to the formulas defined in 3GPP standards such as TS 38.213 and TS 36.213. Example Method

[0085] Figure 4 1 is a flowchart of an example method 400 implemented at a first device according to some example embodiments of the present disclosure. The method 400 may be implemented at the first device 110. For the purpose of discussion, reference will be made to Figure 1 The method 400 is described from the perspective of the first device 110 .

[0086] At block 410, the first device 110 obtains a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite. At block 420, the first device 110 determines a transmission power based on the first path loss and the difference between the first path loss and the second path loss after switching from the source satellite to the target satellite.

[0087] In some example embodiments, the first device 110 may receive a first indication of a time for the switch from the second device.

[0088] In some example embodiments, the first device 110 may determine a difference between the first path loss and the second path loss based on ephemeris information of the source satellite and the target satellite, the location of the first device, and a path loss model.

[0089] In some example embodiments, the first device may receive ephemeris information of the source satellite and the target satellite from the second device.

[0090] In some example embodiments, the path loss model is predefined or configured by the second device 120 .

[0091] In some example embodiments, the first device may receive a difference between the first path loss and the second path loss from the second device.

[0092] In some example embodiments, the difference between the first path loss and the second path loss is received via at least one of: a system information block message prior to handover; a radio resource control message prior to handover; and a message during a random access procedure with the target satellite.

[0093] In some example embodiments, the transmission power is determined in a time window after the switch based on the first path loss and a difference between the first path loss and the second path loss.

[0094] In some example embodiments, the time window is predefined or configured by the second device.

[0095] In some example embodiments, the first device 110 may discard the measurement of the first path loss after the switch; and determine the transmission power based on the measurement of the second path loss after the time window.

[0096] In some example embodiments, the first device 110 may receive, from the second device, a second indication that the difference between the first path loss and the second path loss is enabled for power control.

[0097] In some example embodiments, the second indication is received via at least one of a system information block message or a radio resource control message.

[0098] In some example embodiments, the first apparatus may use transmission power to perform transmissions associated with at least one of: a physical uplink control channel, a physical uplink shared channel, a physical random access channel, or a sounding reference signal.

[0099] Figure 51 shows a flowchart of an example method 500 implemented at a second device according to some example embodiments of the present disclosure. The method 500 may be implemented at the second device 120. For the purpose of discussion, reference will be made to Figure 1 The method 500 is described from the perspective of the second device 120 .

[0100] At block 510, the second device 120 determines that a handover from a source satellite to a target satellite is to be performed for the first device. At block 520, the second device 120 sends information for power control of the first device to the first device before the handover, the information including at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0101] In some example embodiments, the difference between the first path loss and the second path loss is sent via at least one of: a system information block message before handover; a radio resource control message before handover; and a message during a random access procedure with the target satellite.

[0102] In some example embodiments, the second device 120 may send a first indication of a time for switching to the first device.

[0103] In some example embodiments, the second device may send the configuration of the time window to the first device. The power control is performed by the first device in the time window after the handover based on the difference between the first path loss and the second path loss.

[0104] In some example embodiments, the second apparatus may send a second indication to the first apparatus that the difference between the first path loss and the second path loss is enabled for power control.

[0105] In some example embodiments, the second indication is sent via at least one of a system information block message or a radio resource control message.

[0106] With reference above Figures 1 to 3 All operations and features described in relation to the first device 110 and the second device 120 are also applicable to the methods 400 and 500 and have similar effects. For the purpose of simplicity, the details will be omitted. Example devices, equipment, and media

[0107] In some example embodiments, a first device (eg, Figure 1 The first device 110 in the method 400 may include components for performing the corresponding operations of the method 400. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module. The first device may be implemented as or included in Figure 1In the first device 110.

[0108] In some example embodiments, the first device includes: a component for obtaining a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and a component for determining a transmission power based on the first path loss and the difference between the first path loss and the second path loss after switching from the source satellite to the target satellite.

[0109] In some example embodiments, the first apparatus comprises means for receiving a first indication of a time for a switch from the second apparatus.

[0110] In some example embodiments, means for determining the transmission power includes means for determining a difference between the first path loss and the second path loss based on ephemeris information of the source satellite and the target satellite, a location of the first device, and a path loss model.

[0111] In some example embodiments, the first apparatus includes means for receiving ephemeris information of the source satellite and the target satellite from the second apparatus.

[0112] In some example embodiments, the path loss model is predefined or configured by the second device.

[0113] In some example embodiments, means for obtaining a difference between the first path loss and the second path loss includes means for receiving the difference between the first path loss and the second path loss from a second device.

[0114] In some example embodiments, the difference between the first path loss and the second path loss is received via at least one of: a system information block message prior to handover; a radio resource control message prior to handover; and a message during a random access procedure with the target satellite.

[0115] In some example embodiments, the transmission power is determined in a time window after the switch based on the first path loss and a difference between the first path loss and the second path loss.

[0116] In some example embodiments, the time window is predefined or configured by the second device.

[0117] In some example embodiments, the first apparatus includes means for: discarding measurements of the first path loss after the handover; and determining the transmission power based on the measurements of the second path loss after the time window.

[0118] In some example embodiments, the first apparatus includes means for receiving, from the second apparatus, a second indication that a difference between the first path loss and the second path loss is enabled for power control.

[0119] In some example embodiments, the second indication is received via at least one of a system information block message or a radio resource control message.

[0120] In some example embodiments, the first apparatus comprises means for using transmission power to perform transmissions associated with at least one of: a physical uplink control channel, a physical uplink shared channel, a physical random access channel, or a sounding reference signal.

[0121] In some example embodiments, a second device (eg, Figure 1 The second device 120 in the method 500 may include components for performing the corresponding operations of the method 500. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module. The second device may be implemented as or included in Figure 1 In the second device 120.

[0122] In some example embodiments, the second device includes a component for determining that a switch from a source satellite to a target satellite will be performed for the first device; and a component for sending information for power control of the first device to the first device before the switch, the information including at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0123] In some example embodiments, the difference between the first path loss and the second path loss is sent via at least one of: a system information block message before handover; a radio resource control message before handover; and a message during a random access procedure with the target satellite.

[0124] In some example embodiments, the second apparatus comprises means for sending a first indication of a time for the switch to the first apparatus.

[0125] In some example embodiments, the second apparatus includes means for sending a configuration of a time window to the first apparatus, wherein power control is performed by the first apparatus in the time window after the switch based on a difference between the first path loss and the second path loss.

[0126] In some example embodiments, the second apparatus includes means for sending a second indication to the first apparatus that the difference between the first path loss and the second path loss is enabled for power control.

[0127] In some example embodiments, the second indication is sent via at least one of a system information block message or a radio resource control message.

[0128] In some example embodiments, the second apparatus further comprises means for performing the method 500 or other operations in some example embodiments of the second apparatus 120. In some example embodiments, the means comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the execution of the second apparatus.

[0129] Figure 6 600 is a simplified block diagram of a device 600 suitable for implementing an example embodiment of the present disclosure. The device 600 may be provided to implement a communication device, such as Figure 1 1. The first device 110 or the second device 120 shown in FIG. As shown in the figure, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processor 610, and one or more communication modules 640 coupled to the processor 610.

[0130] The communication module 640 is used for two-way communication. The communication module 640 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface may represent any interface necessary for communication with other network elements. In some example embodiments, the communication module 640 may include at least one antenna.

[0131] Processor 610 may be of any type suitable for the local technology network and may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture, as non-limiting examples. Device 600 may have multiple processors, such as application specific integrated circuit chips, which are time-slaved to a clock synchronized with a main processor.

[0132] The memory 620 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 624, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), optical disk, laser disk, and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 622 and other volatile memories that will not persist during a power outage.

[0133] The computer program 630 includes computer executable instructions executed by the associated processor 610. The instructions of the program 630 may include instructions for performing the operations / actions of some example embodiments of the present disclosure. The program 630 may be stored in a memory, such as ROM 624. The processor 610 may perform any suitable actions and processes by loading the program 630 into the RAM 622.

[0134] The exemplary embodiments of the present disclosure may be implemented by a program 630 so that the device 600 may execute a program according to the present disclosure. Figures 1 to 5 Any process of the present disclosure discussed. Example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0135] In some example embodiments, the program 630 may be tangibly embodied in a computer-readable medium, which may be included in the device 600 (such as in the memory 620) or in other storage devices accessible by the device 600. The device 600 may load the program 630 from the computer-readable medium to the RAM 622 for execution. In some example embodiments, the computer-readable medium may include any type of non-transitory storage medium, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. The term "non-transitory" as used herein is a limitation of the medium itself (i.e., tangible, not a signal), not a limitation on data storage persistence (e.g., RAM versus ROM).

[0136] Figure 7 An example of a computer readable medium 700 is shown, which may be in the form of a CD, DVD or other optical storage disc. The computer readable medium 700 has a program 630 stored thereon.

[0137] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or illustrated and described using some other graphical representations, it should be understood that, as non-limiting examples, the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0138] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer-readable medium (such as, non-volatile computer-readable medium). The computer program product includes computer executable instructions, such as those computer executable instructions executed in a device on a target physical or virtual processor included in a program module, to perform any method as described above. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of the program modules can be combined or split between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local storage media and remote storage media.

[0139] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller in a general-purpose computer, a special-purpose computer or other programmable data processing device, so that when the program code is executed by the processor or controller, the function / operation specified in the flow chart and / or block diagram is realized. The program code can be executed entirely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0140] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0141] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. More specific examples of computer readable storage media will include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0142] In addition, although operations are depicted in a particular order, this should not be construed as requiring such operations to be performed in the particular order shown or in a sequential order, or performing all illustrated operations, to achieve the desired result. In some cases, multitasking and parallel processing can be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specified in a particular embodiment. Unless expressly stated, certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, unless expressly stated, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0143] Although the present disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or actions described above. Instead, the specific features and actions described above are disclosed as example forms of implementing the claims.

[0144] Following are some examples of the present disclosure.

[0145] Example 1. A first device comprises: at least one processor; and at least one memory storing instructions, wherein the instructions, when executed by the at least one processor, cause the first device to at least: obtain a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and after switching from the source satellite to the target satellite, determine a transmission power based on the first path loss and the difference between the first path loss and the second path loss.

[0146] Example 2. The first apparatus of example 1, wherein the at least one memory and the at least one processor further cause the first apparatus to: receive a first indication of a time for the switch from a second apparatus.

[0147] Example 3. A first device according to Example 1 or 2, wherein the at least one memory and the at least one processor enable the first device to: determine the difference between the first path loss and the second path loss based on ephemeris information of the source satellite and the target satellite, the position of the first device, and a path loss model.

[0148] Example 4. The first device of Example 3, wherein the at least one memory and the at least one processor further cause the first device to: receive the ephemeris information of the source satellite and the target satellite from the second device.

[0149] Example 5. The first device of Example 3 or 4, wherein the path loss model is predefined or configured by the second device.

[0150] Example 6. The first apparatus of Example 1 or 2, wherein the at least one memory and the at least one processor cause the first apparatus to: receive the difference between the first path loss and the second path loss from a second apparatus.

[0151] Example 7. A first device according to Example 6, wherein the difference between the first path loss and the second path loss is received via at least one of: a system information block message before the handover; a radio resource control message before the handover; and a message during a random access process with the target satellite.

[0152] Example 8. The first apparatus of any one of Examples 1 to 7, wherein the transmission power is determined in a time window after the switching based on the first path loss and the difference between the first path loss and the second path loss.

[0153] Example 9. The first device of Example 8, wherein the time window is predefined or configured by the second device.

[0154] Example 10. A first device according to Example 8 or 9, wherein the at least one memory and the at least one processor further cause the first device to: discard the measurement of the first path loss after the switching; and determine the transmission power based on the measurement of the second path loss after the time window.

[0155] Example 11. A first device according to any one of Examples 1 to 10, wherein the at least one memory and the at least one processor further cause the first device to: receive a second indication from a second device that the difference between the first path loss and the second path loss is enabled for power control.

[0156] Example 12. The first apparatus of Example 11, wherein the second indication is received via at least one of a system information block message or a radio resource control message.

[0157] Example 13. A first device according to any one of Examples 1 to 12, wherein the at least one memory and the at least one processor also cause the first device to: use the transmission power to perform a transmission associated with at least one of the following: a physical uplink control channel, a physical uplink shared channel, a physical random access channel, or a sounding reference signal.

[0158] Example 14. A second device, comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the second device to at least: determine that a switch from a source satellite to a target satellite will be performed for a first device; and before the switch, send information for power control of the first device to the first device, the information including at least one of the following: a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite, and ephemeris information of the source satellite and the target satellite.

[0159] Example 15. A second apparatus according to Example 14, wherein the difference between the first path loss and the second path loss is sent via at least one of: a system information block message before the handover; a radio resource control message before the handover; and a message during a random access procedure with the target satellite.

[0160] Example 16. The second apparatus of Example 14 or 15, wherein the at least one memory and the at least one processor further cause the second apparatus to: send a first indication of a time for the switch to the first apparatus.

[0161] Example 17. The second device of any one of Examples 14 to 16, wherein the at least one memory and the at least one processor further cause the second device to: send a configuration of a path loss model to the first device.

[0162] Example 18. A second device according to any one of Examples 14 to 17, wherein the at least one memory and the at least one processor further cause the second device to: send a configuration of a time window to the first device, wherein the power control is performed by the first device based on the difference between the first path loss and the second path loss in the time window after the switching.

[0163] Example 19. A second device according to any one of Examples 14 to 18, wherein the at least one memory and the at least one processor further cause the second device to: send a second indication to the first device that the difference between the first path loss and the second path loss is enabled for the power control.

[0164] Example 20. The second apparatus of Example 19, wherein the second indication is sent via at least one of a system information block message or a radio resource control message.

[0165] Example 21. A method comprising: obtaining, at a first device, a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and after switching from the source satellite to the target satellite, determining a transmission power based on the first path loss and the difference between the first path loss and the second path loss.

[0166] Example 22. A method comprising: at a second device, determining that a switch from a source satellite to a target satellite will be performed for a first device; and before the switch, sending information for power control of the first device to the first device, the information comprising at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0167] Example 23. A first device comprising: a component for obtaining a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; and a component for determining a transmission power based on the first path loss and the difference between the first path loss and the second path loss after switching from the source satellite to the target satellite.

[0168] Example 24. A second device, comprising: a component for determining that a switch from a source satellite to a target satellite will be performed for a first device; and a component for sending information for power control of the first device to the first device before the switch, the information comprising at least one of the following: a difference between a first path loss associated with the source satellite and a second path loss associated with the target satellite, and ephemeris information of the source satellite and the target satellite.

[0169] Example 25. A non-transitory computer-readable medium comprising program instructions for causing an apparatus to execute the method of Example 21 or Example 22.

Claims

1. A first device for communication, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the first device to at least: obtaining a difference between a first path loss associated with a source satellite and a second path loss associated with a target satellite; as well as After switching from the source satellite to the target satellite, a transmission power is determined based on the first path loss and the difference between the first path loss and the second path loss.

2. The first device of claim 1, wherein the at least one memory and the at least one processor further cause the first device to: A first indication of a time for the switch is received from a second device.

3. The first device according to claim 1 or 2, wherein the at least one memory and the at least one processor enable the first device to: The difference between the first path loss and the second path loss is determined based on the ephemeris information of the source satellite and the target satellite, the position of the first device, and a path loss model.

4. The first device of claim 3, wherein the at least one memory and the at least one processor further cause the first device to: The ephemeris information of the source satellite and the target satellite is received from the second device.

5. The first device according to claim 1 or 2, wherein the path loss model is predefined or configured by the second device.

6. The first device according to claim 1 or 2, wherein the at least one memory and the at least one processor enable the first device to: The difference between the first path loss and the second path loss is received from a second device.

7. The first apparatus of claim 6, wherein the difference between the first path loss and the second path loss is received via at least one of: The system information block message before the switching; Radio resource control message before the handover; and message during a random access procedure with the target satellite. 8 . The first device according to claim 1 , wherein the transmission power is determined in a time window after the switching based on the first path loss and the difference between the first path loss and the second path loss.

9. The first device according to claim 8, wherein the time window is predefined or configured by the second device.

10. The first device of claim 8, wherein the at least one memory and the at least one processor further cause the first device to: discarding the measurement of the first path loss after the switching; and After the time window, the transmission power is determined based on the measurement of the second path loss.

Images