WO2024060072A1 - 通信方法及装置 - Google Patents

通信方法及装置 Download PDF

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Publication number
WO2024060072A1
WO2024060072A1 PCT/CN2022/120250 CN2022120250W WO2024060072A1 WO 2024060072 A1 WO2024060072 A1 WO 2024060072A1 CN 2022120250 W CN2022120250 W CN 2022120250W WO 2024060072 A1 WO2024060072 A1 WO 2024060072A1
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WO
WIPO (PCT)
Prior art keywords
ssb
cell
terminal device
time
configuration information
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PCT/CN2022/120250
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English (en)
French (fr)
Inventor
汪宇
罗禾佳
王俊
周建伟
张希
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华为技术有限公司
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Priority to PCT/CN2022/120250 priority Critical patent/WO2024060072A1/zh
Publication of WO2024060072A1 publication Critical patent/WO2024060072A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/04—Reselecting a cell layer in multi-layered cells
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements

Definitions

  • the present application relates to the field of communication technology, and in particular to a communication method and device.
  • NTN non-terrestrial networks
  • LEO Starlink ultra-dense low earth orbit
  • the coverage range of a satellite can reach thousands or even tens of thousands of kilometers, while the coverage range of a beam can reach tens of meters or even kilometers.
  • a satellite In order to support satellite wide-area coverage, a satellite usually has to be configured with dozens, hundreds, or even more beams.
  • beam hopping can be used to provide regional coverage. That is, a satellite can be configured with more beams to cover a wider area, but only use a smaller number of beams at the same time for regional coverage, and cover a wider area by using multiple beams at different times.
  • a satellite is configured with 16 beams to cover a wide area, but only 4 beams are used for regional coverage at a time.
  • T1 four beams numbered 0, 1, 4, and 5 are used for area coverage;
  • T2 four beams numbered 2, 3, 6, and 7 are used for area coverage.
  • all areas covered by a single satellite that is, the areas corresponding to 16 beams) are served in a time-sharing manner through T1, T2, T3, and T4.
  • terminal equipment in the area covered by one or more beams may need to perform frequent cell switching or cell reselection.
  • the terminal equipment needs to measure the SSB of the target cell. How to improve the efficiency of measuring SSB is a problem that needs to be solved.
  • This application provides a communication method and device to improve the efficiency of measuring SSB.
  • inventions of the present application provide a communication method.
  • the method includes: the first cell may send a first SSB, and the first SSB is an SSB used for initial access.
  • the first cell may also send a second SSB, which is the SSB used for cell handover or cell reselection.
  • the first SSB is not used for cell switching or cell reselection. In this way, the terminal device that receives the first SSB will not switch or reselect to the first cell based on the first SSB.
  • the second SSB is not used for initial access. In this way, the terminal device that receives the second SSB will not initially access the first cell based on the second SSB.
  • the first cell can respectively send the first SSB for initial access and the second SSB for cell handover or cell reselection.
  • the first cell can send the first SSB; when the terminal device needs to switch or reselect to the first cell, the first cell can send the second SSB, so that it can be sent on demand.
  • SSB reduces the overhead of sending SSB and improves the efficiency of terminal equipment measuring SSB.
  • the first cell may send the first SSB in the first area and the second SSB in the second area.
  • the first area may be an area where the first cell sends data signals
  • the second area may be included in an area where the second cell sends data signals.
  • the first cell can send the first SSB for initial access in the first area, and the second SSB for cell handover or cell reselection in the second area.
  • the terminal equipment located in the second area can perform broadcast signal quality measurement and downlink synchronization according to the second SSB before the first cell covers the second area using the beam used to transmit the data signal, thereby
  • seamless reselection or handover to the first cell can be performed to improve the efficiency of cell reselection and cell handover.
  • the first cell may also send configuration information to the second cell, and the configuration information may be used to instruct the first cell to send the configuration of the second SSB. Then, the second cell may send the configuration information to the terminal device in the second cell.
  • the first cell can send a configuration for instructing the first cell to send the second SSB to other cells (eg, neighboring cells of the first cell). In this way, terminal equipment in other cells can receive the second SSB according to the configuration information, thereby avoiding blind detection of the second SSB by the terminal equipment, thereby reducing energy consumption of the terminal equipment.
  • the transmission time of the first SSB and the transmission time of the second SSB do not overlap.
  • the transmission time of the first SSB and the second SSB is time-divided.
  • the first SSB and the second SSB do not overlap in the time domain, thereby reducing interference between the first SSB and the second SSB.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • the transmission period of the first SSB is one of the following: 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms; the transmission period of the second SSB is several to several hundred seconds.
  • the transmission period of the first SSB is shorter than the transmission period of the second SSB, thereby reducing the overhead of sending the second SSB.
  • both the first SSB and the second SSB are NR SSBs. That is to say, the first SSB and the second SSB can reuse the pattern of the NR SSB. This design can reuse the NR SSB pattern, which improves the usability of the solution and is easy to implement.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • the first SSB can reuse the pattern of the NR SSB, occupy the time window of the NR SSB, and use the sequence number of the NR SSB.
  • the second SSB does not occupy the time window of the NR SSB and does not use the sequence number of the NR SBB.
  • the second SSB does not use the time window and sequence number of the NR SSB, which can expand more available SSBs and improve the efficiency of cell reselection and cell handover.
  • the NCD-SSB corresponds to resources used for handover and/or a random access preamble used for handover.
  • the correspondence between the NCD-SSB and the resources used for handover and/or the random access preamble used for handover may be preset, or may be a network device (for example, the first satellite or a network device located on the ground). etc.) determined.
  • NCD-SSB can be associated with dedicated handover resources and/or random access preamble for handover, which can be used for uplink random access during group handover, thereby improving the efficiency of group handover.
  • the terminal device does not need to obtain resource configuration information for group handover, thereby reducing overhead.
  • the random access preamble associated with NCD-SSB the conflict between the random access preamble used for handover and the random access preamble used for initial access can be avoided, thereby improving the success rate of group handover.
  • the first cell may send a first offset indication to the second cell.
  • the first offset indication is used to indicate the transmission time of the second SSB and the transmission of the first SSB adjacent to the second SSB. The time offset between times.
  • the second cell may send the first offset indication to the terminal device in the second cell.
  • the terminal device can receive the first SSB from the first cell according to the first offset indication and the time when the second SSB is received, so that there is no need for the terminal device to blindly detect the first SSB, and there is no need for the second cell to report the first SSB to the terminal device.
  • Sending the configuration information of the first SSB can thereby reduce the energy consumption of the terminal device and reduce the cost of obtaining the configuration information of the first SSB.
  • the first cell may also update the configuration of the first cell to send the second SSB, but does not update the SIB of the first cell.
  • the first cell when updating the configuration of the first cell to send the second SSB, the first cell does not update the SIB of the first cell, thereby reducing the overhead required to update the SIB.
  • an embodiment of the present application provides a communication method.
  • the method includes: after receiving a third SSB from a second cell, the terminal device can access the second cell according to the third SSB.
  • the third SSB is an SSB for initial access. At this time, the terminal device can be in a connected state.
  • the terminal device After receiving a second SSB from a first cell, the terminal device can send a measurement report to the second cell according to the second SSB.
  • the second SSB is an SSB for cell switching or cell reselection.
  • the terminal equipment in the connected state can switch to the first cell according to the second SSB.
  • the efficiency of group switching can be improved.
  • the terminal device may also receive configuration information from the second cell, and receive the second SSB from the first cell according to the configuration information.
  • the configuration information is used to indicate the configuration of the first cell to send the second SSB.
  • the terminal device may receive the second SSB from the first cell according to the second configuration information, thereby avoiding blind detection of the second SSB by the terminal device, and further reducing energy consumption of the terminal device.
  • the second SSB is an NCD-SSB.
  • the terminal device may communicate with the first cell using resources for handover corresponding to the NCD-SSB and/or a random access preamble for handover.
  • the correspondence between the NCD-SSB and the resources used for handover and/or the random access preamble used for handover may be preset, or may be a network device (for example, the first satellite or a network device located on the ground). etc.) determined.
  • NCD-SSB can be associated with dedicated handover resources and/or random access preamble for handover, which can be used for uplink random access during group handover, thereby improving the efficiency of group handover.
  • the terminal device does not need to obtain resource configuration information for group handover, thereby reducing overhead.
  • the random access preamble associated with NCD-SSB the conflict between the random access preamble used for handover and the random access preamble used for initial access can be avoided, thereby improving the success rate of group handover.
  • the terminal device may receive a handover command from the second cell, where the handover command is used to instruct the terminal device to switch to the first cell.
  • the terminal device may then receive a first SSB from the first cell, the first SSB being the SSB used for initial access.
  • the terminal device can receive the first SSB from the first cell in a timely manner after receiving the handover command from the second cell.
  • the terminal device may receive the first offset indication, and receive the first SSB from the first cell according to the first offset indication and the time at which the second SSB is received.
  • the first offset indication is used to indicate a time interval between the sending time of the second SSB and the sending time of the first SSB adjacent to the second SSB.
  • the terminal device can receive the first SSB from the first cell according to the first offset indication and the time when the second SSB is received, so that there is no need for the terminal device to blindly detect the first SSB, and there is no need for the second cell to report the first SSB to the terminal device.
  • Sending the configuration information of the first SSB can thereby reduce the energy consumption of the terminal device and reduce the cost of obtaining the configuration information of the first SSB.
  • the first SSB is not used for cell switching or cell reselection, so that a terminal device receiving the first SSB will not switch or reselect to the first cell according to the first SSB.
  • the second SSB is not used for initial access, so that a terminal device receiving the second SSB will not initially access the first cell according to the second SSB.
  • the sending time of the first SSB and the sending time of the second SSB do not overlap.
  • the transmission time of the first SSB and the second SSB is time-divided.
  • the first SSB and the second SSB do not overlap in the time domain, thereby reducing interference between the first SSB and the second SSB.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • the transmission period of the first SSB is one of the following: 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms; the transmission period of the second SSB is several to several hundred seconds.
  • the transmission period of the first SSB is shorter than the transmission period of the second SSB, thereby reducing the overhead of sending the second SSB.
  • the first SSB and the second SSB are both NR SSB. That is, the first SSB and the second SSB can reuse the pattern of NR SSB.
  • This design can reuse the pattern of NR SSB, improves the availability of the solution, and is easy to implement.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • the first SSB can reuse the pattern of the NR SSB, occupy the time window of the NR SSB, and use the sequence number of the NR SSB.
  • the second SSB does not occupy the time window of the NR SSB and does not use the sequence number of the NR SBB.
  • the second SSB does not use the time window and sequence number of the NR SSB, which can expand more available SSBs and improve the efficiency of cell reselection and cell handover.
  • embodiments of the present application provide a communication method.
  • the method includes: the terminal equipment receives a second synchronization signal block SSB from the first cell, and the second SSB is an SSB used for cell switching or cell reselection.
  • the terminal device may further receive a first offset indication, the first offset indication being used to indicate a time offset between the sending time of the second SSB and the sending time of the first SSB adjacent to the second SSB, the first SSB is the SSB used for initial access.
  • the terminal device may receive the first SSB from the first cell according to the time when the second SSB is received and the first offset indication.
  • the terminal equipment in the idle state can be reselected to the first cell according to the second SSB.
  • the efficiency of group reselection can be improved.
  • the first SSB is not used for cell switching or cell reselection, so that the terminal device that receives the first SSB will not switch or reselect to the first cell based on the first SSB.
  • the second SSB is not used for initial access. In this way, the terminal device that receives the second SSB will not initially access the first cell based on the second SSB.
  • the sending time of the first SSB and the sending time of the second SSB do not overlap.
  • the transmission time of the first SSB and the second SSB is time-divided.
  • the first SSB and the second SSB do not overlap in the time domain, thereby reducing interference between the first SSB and the second SSB.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • the transmission period of the first SSB is one of the following: 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms; the transmission period of the second SSB is several to several hundred seconds.
  • the transmission period of the first SSB is shorter than the transmission period of the second SSB, thereby reducing the overhead of sending the second SSB.
  • both the first SSB and the second SSB are NR SSBs. That is to say, the first SSB and the second SSB can reuse the pattern of the NR SSB. This design can reuse the NR SSB pattern, which improves the usability of the solution and is easy to implement.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • the first SSB can reuse the pattern of the NR SSB, occupy the time window of the NR SSB, and use the sequence number of the NR SSB.
  • the second SSB does not occupy the time window of the NR SSB and does not use the sequence number of the NR SBB.
  • the second SSB does not use the time window and sequence number of the NR SSB, which can expand more available SSBs and improve the efficiency of cell reselection and cell handover.
  • an embodiment of the present application provides a communication device, comprising a unit for executing each step in any of the above aspects.
  • embodiments of the present application provide a communication device, including at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to read and execute The storage element stores programs and data, so that the method provided by any of the above aspects of this application is implemented.
  • embodiments of the present application provide a communication system, including: a first cell for performing the method provided by the first aspect, and a terminal device used for performing the method provided by the second or third aspect.
  • embodiments of the present application also provide a computer program, which when the computer program is run on a computer, causes the computer to execute the method provided in any of the above aspects.
  • embodiments of the present application further provide a computer-readable storage medium.
  • a computer program is stored in the computer-readable storage medium. When the computer program is executed by a computer, it causes the computer to execute any of the above. methods provided.
  • an embodiment of the present application further provides a chip, which is used to read a computer program stored in a memory and execute a method provided in any of the above aspects.
  • an embodiment of the present application further provides a chip system, which includes a processor for supporting a computer device to implement the method provided in any of the above aspects.
  • the chip system also includes a memory, which is used to store the necessary programs and data of the computer device.
  • the chip system can be composed of a chip, or it can include a chip and other discrete devices.
  • Figure 1 is a schematic diagram of the beam hopping communication process in the embodiment of the present application.
  • Figure 2A is a schematic diagram of an application scenario of a transparent transmission mode in an embodiment of the present application
  • Figure 2B is a schematic diagram of an application scenario of a non-transparent transmission mode in an embodiment of the present application
  • Figure 3 is a schematic architectural diagram of a mobile communication system in an embodiment of the present application.
  • Figure 4 is an architectural schematic diagram of another mobile communication system in an embodiment of the present application.
  • FIG. 5 is a schematic diagram of the cell-defined synchronization signal block (SSB) (cell defining SSB, CD-SSB) and the non-cell defining SSB (Non-cell defining SSB, NCD-SSB) in the embodiment of the present application;
  • SSB cell-defined synchronization signal block
  • Figure 6 is a flow chart of a switching method
  • Figure 7A is a flow chart of a communication method in an embodiment of the present application.
  • Figure 7B is a flow chart of a possible implementation of a communication method in an embodiment of the present application.
  • Figure 8 is a schematic diagram of a mapping relationship between SSB and wave position in an embodiment of the present application.
  • Figure 9 is a schematic diagram of the time domain positions of the first SSB and the second SSB in the embodiment of the present application.
  • Figure 10 is a schematic diagram of the time domain positions of another first SSB and second SSB in an embodiment of the present application.
  • Figure 11 is a schematic diagram of the positions of the first RO and the second RO in the embodiment of the present application.
  • Figure 12 is a flow chart of another communication method in an embodiment of the present application.
  • Figure 13 is a schematic diagram of the coverage area of the first satellite at different times in the embodiment of the present application.
  • Figure 14 is a flow chart of another communication method in the embodiment of the present application.
  • Figure 15 is a flow chart of yet another communication method in the embodiment of the present application.
  • Figure 16 is a schematic diagram of the coverage area of the first satellite and the second satellite at different times in the embodiment of the present application;
  • Figure 17 is a structural diagram of a communication device provided by an embodiment of the present application.
  • Figure 18 is a structural diagram of another communication device provided by an embodiment of the present application.
  • Embodiments of the present application provide a communication method and device, wherein the method and the device are based on the same technical concept. Since the methods and devices solve problems in similar principles, the implementation of the device and the method can be referred to each other, and repeated details will not be repeated. .
  • Communication device generally refers to a device with communication functions.
  • the communication device may be, but is not limited to, terminal equipment, network equipment, relay equipment, ground station equipment, etc.
  • Network equipment is a device in a mobile communication system that connects terminal equipment to a wireless network.
  • network equipment can also be called a base station, a radio access network (RAN) node (or device), an access point (AP), or an access network. ,AN) equipment.
  • RAN radio access network
  • AP access point
  • AN access network
  • network equipment are: new generation Node B (gNB), transmission reception point (TRP), evolved Node B (evolved Node B, eNB), wireless network controller (radio network controller (RNC), Node B (Node B, NB), base station controller (BSC), base transceiver station (BTS), wireless relay node, wireless backhaul node, transmission point ( transmitting point, TP), mobile switching center or home base station (e.g., home evolved NodeB, or home Node B, HNB).
  • the network device may also be an antenna panel or a group of antenna panels of a base station.
  • the network device can also be a network node that constitutes a gNB or TP, such as a baseband unit (BBU) or a distributed unit (DU).
  • Network devices can also be device-to-device (D2D) communication systems, machine-to-machine (M2M) communication systems, Internet of Things (IoT), Internet of Vehicles communication systems, or other communications A device that assumes network-side functions in the system.
  • D2D device-to-device
  • M2M machine-to-machine
  • IoT Internet of Things
  • Vehicles Internet of Vehicles communication systems
  • Terminal equipment is a device that provides voice and/or data connectivity to users.
  • Terminal equipment can also be called user equipment (UE), terminal, access terminal, terminal unit, terminal station, user unit, user station, mobile station (MS), remote station, remote terminal, mobile terminal (MT), wireless communication equipment, customer premises equipment (CPE), wireless communication equipment, user agent, user device or terminal agent, etc.
  • UE user equipment
  • MS mobile station
  • MT mobile terminal
  • CPE customer premises equipment
  • the terminal device can be a handheld device with wireless connection function, or it can be a vehicle with communication function, a vehicle-mounted device (such as a vehicle-mounted communication device, a vehicle-mounted communication chip), a wearable device, a computing device, or other processing device connected to a wireless modem.
  • a vehicle-mounted device such as a vehicle-mounted communication device, a vehicle-mounted communication chip
  • a wearable device such as a wearable device, a computing device, or other processing device connected to a wireless modem.
  • terminal devices are: mobile phones, satellite phones, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless data cards, wireless modems, machine type communication devices, wireless local loop (WLL) stations, personal digital assistant (PDA) devices, tablet computers, computers with wireless transceiver functions, laptops, PDAs, mobile Internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc.
  • SIP session initiation protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • MID mobile Internet devices
  • VR virtual reality
  • AR augmented reality
  • Ground station equipment is a device that is set on the ground and can communicate with NTN equipment in the NTN system.
  • Ground station equipment is, for example, core network (CN) equipment.
  • CN equipment is a network element contained in the CN part of the mobile communication system.
  • CN equipment can connect terminal equipment to different data networks, and perform authentication, billing, mobility management, session management, policy control, user plane forwarding and other services.
  • the CN equipment may be a CN equipment in a current mobile communication system (such as a 5th generation (5G) mobile communication system), or a CN equipment in a future mobile communication system.
  • 5G 5th generation
  • the names of CN devices with the same functions may be different. However, the embodiments of the present application do not limit the specific names of CN devices with each function.
  • the network element responsible for functions such as access control, security control, and signaling coordination is the mobility management entity (Mobile management entity, MME); the network element as the local mobility management anchor point is the serving gateway (S-GW); as the anchor point for external data network handover, it is responsible for Internet protocol (internet protocol, IP) address allocation
  • the network element is the packet data network (PDN) gateway (PDN gateway, P-GW); the network element that stores user-related data and subscription data is the home subscriber server (HSS); responsible for policy and planning Network elements with charging functions are called policy and charging rule function (PCRF) network elements.
  • PDN packet data network gateway
  • HSS home subscriber server
  • PCRF policy and charging rule function
  • the core network can be divided into a control plane (CP) and a user plane (UP).
  • CP control plane
  • UP user plane
  • network elements in the CN that are responsible for control plane functions can be collectively called control plane network elements
  • network elements that are responsible for user plane functions can be collectively called user plane network elements.
  • the network element that serves as the interface of the data network and is responsible for user plane data forwarding and other functions is the user plane function (UPF) network element.
  • UPF user plane function
  • the network element responsible for access control and mobility management functions is called the access and mobility management function (AMF) network element; the network element responsible for session management and control policy execution is called It is a session management function (SMF) network element; the network element responsible for managing subscription data, user access authorization and other functions is called a unified data management (UDM) network element; it is responsible for billing and policy control functions.
  • the network element is called the policy control function (Policy and charging function, PCF) network element; the application function (AF) network element is responsible for transmitting the requirements of the application side to the network side.
  • Policy and charging function Policy and charging function
  • PCF policy control function
  • AF application function
  • NTN communications can use drones, high altitude platform stations (HAPS), satellites and other equipment to form a network to provide data transmission, voice communication and other services for terminal equipment.
  • the height of the high-altitude platform from the ground can be 8 to 50 kilometers (km).
  • the satellite communication system in NTN communications can include geostationary earth orbit (GEO) satellites, medium earth orbit (MEO) satellites and low earth orbit (low-earth) satellites. orbit, LEO) satellite. They are described separately below.
  • GEO satellite also known as geostationary satellite or geostationary satellite.
  • the motion speed of GEO satellites is the same as the rotation speed of the earth. Therefore, GEO satellites remain stationary relative to the ground.
  • the cells of GEO satellites are also stationary.
  • GEO satellites have higher orbits.
  • the orbital altitude of GEO satellites can be 35,786km, which can provide a larger coverage area.
  • the cell diameter of GEO satellites can usually be 500km.
  • MEO satellite is a non-geostationary earth orbit (NGEO) satellite.
  • NGEO non-geostationary earth orbit
  • the motion speed of non-geostationary satellites is different from the rotation speed of the earth. Therefore, non-geostationary satellites move relative to the ground.
  • the orbital altitude of MEO satellites is in the range of 2000 to 35786km, and global coverage can be achieved with a relatively small number of satellites.
  • MEO satellites are mainly used for positioning and navigation.
  • LEO satellite It is another type of NGEO satellite.
  • the orbital altitude of LEO satellites is in the range of 300 to 2000km, which has the advantages of small data propagation delay, small transmission loss, and low launch cost.
  • LEO satellites move relatively fast relative to the ground, about 7km/s. Therefore, the coverage area provided by LEO satellites also moves accordingly.
  • the working modes of NTN equipment may include: a transparent mode and a non-transparent mode.
  • Transparent transmission is also called elbow forwarding transmission.
  • NTN equipment has a relay and forwarding function when working in transparent transmission mode. NTN equipment can frequency convert and/or amplify the signal, but will not change the content of the signal.
  • An exemplary application scenario of transparent transmission mode can be shown in Figure 2A.
  • the network equipment is set up on the ground and can be connected to the data network (DN) through the CN; the satellite and gateway equipment can be used as the remote radio unit (RRU) of the network equipment. , used to transfer information between network devices and terminal devices.
  • DN data network
  • RRU remote radio unit
  • the non-transparent transmission mode can also be called the regenerative mode.
  • the NTN device working in the non-transparent transmission mode has all or part of the capabilities of the network device.
  • the application scenario of the non-transparent transmission mode can be shown in Figure 2B.
  • the satellite can be used as a network device to form an access network with a gateway device, and communicate with the core network through the gateway device.
  • the satellite can be used as a network device to establish an N2 interface or Ng interface connection with the AMF in the core network through the gateway device.
  • the satellite can also provide wireless access services for terminal devices.
  • SSB which can include primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH).
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • PBCH physical broadcast channel
  • PSS can be used to transmit the cell number
  • SSS can be used to transmit the cell group number.
  • the cell number and the cell group number jointly determine multiple physical cell numbers (physical cell identity, PCI) in the mobile communication system.
  • the system information in the SSB can be carried by the PBCH. Since this information is necessary for the terminal device to access the network, it can be called the main information block (MIB).
  • the MIB may include the system frame number and the subcarrier spacing for initial access, etc.
  • the information contained in the MIB is limited and not enough to support terminal equipment accessing the cell. Therefore, the terminal device can also obtain other system information, such as system information block (SIB)1.
  • SIB1 can be transmitted on the physical downlink shared channel (PDSCH) with a cycle of 160 milliseconds (ms).
  • PDSCH physical downlink shared channel
  • the terminal device can obtain the parameters used for SIB1 transmission in the MIB carried by the PBCH, so that it can receive SIB1. In this way, the terminal device can obtain the system information required to access the cell, and can subsequently access the cell.
  • Radio resource control (RRC) connection status In the mobile communication system, the RRC connection state of the terminal device includes: RRC connected state (RRC_connected, referred to as connected state), RRC idle state (RRC_idle, referred to as idle state).
  • the terminal device When the terminal device is in idle state, the RRC connection between the terminal device and the network device is disconnected. The network device and the terminal device no longer save the terminal device context information.
  • the terminal device can receive broadcast information (such as system information) and paging messages sent by the network device. .
  • the terminal device When the terminal device is in the connected state, there is an RRC connection between the terminal device and the network device, and the two can communicate through the RRC connection.
  • the terminal device In the RRC connection state, if cell handover failure, wireless link failure, RRC connection reconfiguration (RRC connection reconfiguration) process failure, etc. occur, the terminal device will trigger the RRC connection reestablishment process.
  • the parameters used to reflect signal quality may include but are not limited to at least one of the following: reference signal receiving power (RSRP), reference signal receiving quality (reference signal receiving quality, RSRQ), Or received signal strength indication (RSSI).
  • RSRP reference signal receiving power
  • RSRQ reference signal receiving quality
  • RSSI received signal strength indication
  • Wave position can be the area covered by the beam.
  • the area covered by beam 0 is one wave position.
  • the device used to implement the function of the satellite may be a satellite; it may also be a device capable of supporting a shape to implement the function, such as a chip system, and the device may be installed in the satellite.
  • the technical solution provided by the embodiment of the present application will be described by taking the device for realizing the function of the satellite as a satellite as an example.
  • the device for realizing the function of the terminal device may be a terminal device; it may also be a device that can support the terminal device to realize the function, such as a chip system, and the device may be installed in the terminal device.
  • the chip system may be composed of chips, or may include chips and other discrete devices.
  • the number of nouns means “singular noun or plural noun", that is, “one or more”, unless otherwise specified. "At least one” means one or more, and “plurality” means two or more. "And/or” describes the relationship between associated objects, indicating that there can be three relationships. For example, A and/or B can mean: A alone exists, A and B exist simultaneously, and B alone exists. “At least one of the following” or similar expressions refers to any combination of these items (items), including any combination of a single item (items) or a plurality of items (items).
  • Figure 3 shows the structure of a mobile communication system to which the method provided by the embodiment of the present application is applicable.
  • the system includes: network equipment and terminal equipment (for example, terminal equipment a and terminal equipment b shown in Figure 3).
  • the network device is an entity on the network side that can receive and transmit wireless signals. It is responsible for providing wireless access-related services to terminal devices within its coverage, and realizing physical layer functions, resource scheduling and wireless resource management, and service quality ( Quality of Service (QoS) management, wireless access control and mobility management functions.
  • QoS Quality of Service
  • the terminal device is an entity on the user side that can receive and transmit wireless signals, and needs to access the network through the network device.
  • the terminal device may be various devices that provide voice and/or data connectivity for users.
  • the terminal device may be a vehicle-mounted device, a smart phone, etc.
  • Figure 4 shows the structure of another mobile communication system to which the method provided by the embodiment of the present application is applicable.
  • the communication system may be an NTN communication system.
  • the NTN communication system is a satellite communication system as an example for explanation.
  • the NTN communication system includes satellites (for example, satellite 401, satellite 402 and satellite 403 in Figure 4), CN equipment and terminal equipment.
  • CN equipment and the terminal equipment please refer to the above description of the CN equipment and the terminal equipment respectively.
  • the satellite may be an NGEO satellite, for example, a LEO satellite.
  • the satellite may communicate wirelessly with the terminal device by broadcasting communication signals and navigation signals.
  • each satellite may provide communication services, navigation services, and positioning services to the terminal device through multiple beams.
  • each satellite uses multiple beams to cover the service area, and the relationship between different beams may be one or more of time division, frequency division, and space division.
  • At least one satellite may communicate with a ground station device.
  • satellite 403 may be connected to a CN device and communicate wirelessly with the CN device.
  • the satellite can work in the transparent transmission mode.
  • the satellite 403 in Figure 4 works in the transparent transmission mode.
  • Satellites may also operate in a non-transparent transmission mode.
  • satellite 401 and satellite 402 in Figure 4 operate in a non-transparent transmission mode.
  • satellites can also operate in quasi earth-fixed mode or satellite-fixed mode.
  • the quasi earth-fixed mode can also be called the staring mode, which refers to dynamically adjusting the beam pointing of the satellite so that it can continue to serve a certain physical area for a period of time.
  • Satellite-fixed mode means that the satellite's beam moves with the satellite, and the physical area it serves also continuously changes.
  • the satellites mentioned in the embodiments of this application may be satellite base stations, may also include orbital receivers or repeaters for relaying information, or may be network equipment mounted on satellites.
  • the mobile communication system shown in Figure 3 or Figure 4 is used as an example and does not limit the communication systems to which the methods provided by the embodiments of the present application are applicable. In short, the methods provided by the embodiments of the present application are applicable to communication systems and application scenarios in which various terminal devices support multiple transmission capabilities.
  • the embodiments of the present application can also be applied to various types and formats of communication systems, such as: 5G communication systems , LTE communication system, wireless fidelity (Wi-Fi) system, vehicle to everything (V2X), long-term evolution - Internet of Vehicles (LTE-vehicle, LTE-V), vehicle to vehicle (vehicle to vehicle (V2V), Internet of Vehicles, machine type communications (MTC), Internet of things (IoT), long-term evolution-machine to machine (LTE-machine to machine, LTE-M), machine-to-machine (machine to machine, M2M), integrated communication and navigation (IcaN) system, global navigation satellite system (global navigation satellite system, GNSS) or ultra-dense low-orbit satellite communication system, etc., the embodiments of this application do not limited.
  • 5G communication systems LTE communication system, wireless fidelity (Wi-Fi) system, vehicle to everything (V2X), long-term evolution - Internet of Vehicles (LTE-vehicle, LTE
  • CD-SSB and NCD-SSB 1. CD-SSB and NCD-SSB:
  • CD-SSB includes: the configuration information of the associated control resource set (ie, the configuration information of CORESET 0), and the Type0 physical downlink control channel common search space (Type0-PDCCH) CSS) monitoring timing configuration information.
  • CD-SSB can be used for initial access, cell reselection or cell handover.
  • the terminal equipment in the idle state can perform initial access or cell reselection based on CD-SSB.
  • the terminal equipment in the connected state can perform cell switching according to CD-SSB.
  • NCD-SSB does not include: the configuration information of the associated control resource set (that is, the configuration information of CORESET 0), or the configuration information of the monitoring timing of Type 0-PDCCH CSS. NCD-SSB can be used for wireless resource management.
  • CD-SSB and NCD-SSB are frequency division multiplexed, that is, CD-SSB and NCD-SSB are carried on different frequencies.
  • CD-SSB and NCD-SSB are carried on different bandwidth parts (bandwidth part, BWP).
  • BWP bandwidth part
  • CD-SSB includes SSB1 and SSB3
  • NCD-SSB includes SSB2 and SSB4.
  • the working frequency of UE1 includes the initial BWP (initial BWP), for example, the working frequency of UE1 is dedicated BWP1 (dedicated BWP1), and the dedicated BWP1 includes the initial BWP, then UE1 can perform initial access, cell handover or cell switching according to SSB3 in the initial BWP. Neighborhood reselection.
  • the NCD-SSB is located outside the initial BWP, and terminal equipment with an operating frequency outside the initial BWP can perform signal measurements based on the NCD-SSB. For example, if the operating frequency of UE2 is dedicated BWP2, and dedicated BWP2 does not include the initial BWP, UE2 can perform signal measurement based on SSB4.
  • the terminal device can determine the position of the CD-SSB in the frequency domain based on the frequency offset.
  • the frequency offset can be indicated by the parameter K_SSB carried in the NCD-SSB, and corresponds to the SSB subcarrier offset (ssb-SubcarrierOffset) parameter in the main information block (main information block, MIB) message.
  • the network device can send measurement configuration information to the terminal device through the RRC connection reconfiguration message.
  • the terminal device measures the signal strength of the serving cell and neighboring cells according to the measurement configuration information issued by the network device, and reports the measurement results. Then, the network device can decide whether to perform handover based on the measurement results.
  • the current switching process will be described below with reference to Figure 6.
  • the source network device sends a first RRC reconfiguration (RRCReconfiguration) message to the terminal device.
  • RRCReconfiguration RRC reconfiguration
  • the first RRC reconfiguration message may include measurement configuration information of at least one cell.
  • the at least one cell may include a serving cell and a neighbor cell of the terminal device.
  • the terminal device sends a first RRC reconfiguration complete (RRCReconfigurationComplete) message to the source network device.
  • RRCReconfigurationComplete RRC reconfiguration complete
  • the first RRC reconfiguration complete message may be used to indicate that the terminal device has received the first RRC reconfiguration message.
  • the terminal device performs measurement according to the measurement configuration information, and sends a measurement report to the source network device.
  • the terminal device may use the SSB associated with the currently activated BWP to measure the serving cell and/or neighboring cells according to the measurement configuration information.
  • the terminal device can periodically send measurement reports to the source network device.
  • the period for sending measurement reports can be preset, or the terminal device can obtain it from the source network device.
  • the terminal device can send a measurement report to the source network device when the measurement results meet the reporting conditions.
  • the reporting condition may include at least one of the following: the signal quality of the serving cell is less than or equal to the first signal quality threshold, and the signal quality of the neighboring cell is greater than or equal to the second signal quality threshold.
  • the source network device performs handover decision based on the measurement report from the terminal device.
  • the source network device may determine to switch the terminal device to the target network device.
  • S605 The source network device sends a handover request message to the target network device.
  • the switching request is used to request to switch the terminal device from the source network device to the target network device.
  • S606 The target network device performs admission control.
  • the target network device may configure the end device with the resources required for handover.
  • the target network device sends a handover request acknowledgment message to the source network device.
  • the handover request response message may be used to indicate that the target network device agrees to handover the terminal device to the target network device.
  • the source network device sends a second RRC reconfiguration message to the terminal device.
  • the second RRC reconfiguration message may also be called a handover command and is used to instruct the terminal device to switch from the source network device to the target network device.
  • the second RRC reconfiguration message may include configuration parameters of the cell of the target network device, for example, the identity of the cell of the target network device, or the frequency point of the cell of the target network device.
  • S609 The source network device sends a sequence number (SN) status transfer (SN status transfer) message to the target network device.
  • SN sequence number
  • the SN state transfer message may include a sequence number used to indicate that the source network device has transmitted the data packet to the terminal device.
  • the source network device forwards the data to be sent to the terminal device to the target network device.
  • the terminal device sends a random access (random access) message to the target network device according to the configuration parameters of the cell of the target network device in the second RRC reconfiguration message to request access to the cell of the target network device.
  • a random access (random access) message to the target network device according to the configuration parameters of the cell of the target network device in the second RRC reconfiguration message to request access to the cell of the target network device.
  • the random access preamble in the random access message is a dedicated preamble, which is different from the contention-based random access preamble used in the initial access.
  • the period for transmitting the random access resource may be at least one of the following: 10 ms, 20 ms, 40 ms, 80 ms or 160 ms.
  • the target network device sends a random access response (RAR) message to the terminal device.
  • RAR random access response
  • the terminal device sends the second RRC reconfiguration completion message to the target network device.
  • the terminal device After accessing the target network device, the terminal device can interact with the target network device for data. For example, the end device can send upstream data to the target network device. For another example, the terminal device may receive downlink data from the target network device.
  • the target network device sends a path switch request message to the AMF.
  • the path switching request message can be used to request the core network to send the data of the terminal device to the target network device.
  • S614 AMF sends a path switch request acknowledgment message to the target network device.
  • the target network device may send uplink data from the terminal device to the core network.
  • the terminal device can switch from the source network device to the target network device.
  • the terminal device When the terminal device is in the idle state, after camping on the serving cell, the terminal device can continuously perform cell reselection by measuring the signal strength of the serving cell and neighboring cells in order to camp on a cell with higher priority or better channel quality. community.
  • the cell reselection process may include steps H1-H3:
  • the cell of the first network device broadcasts the measurement configuration information of at least one cell.
  • the at least one cell may include a serving cell and a neighbor cell of the terminal device.
  • the terminal device measures the signal quality of at least one cell based on the measurement configuration information.
  • the terminal device can use the SSB with currently activated BWP association to measure the serving cell and/or neighboring cells according to the measurement configuration information, thereby obtaining the signal quality of the serving cell and/or neighboring cells.
  • the terminal device can reselect to the cell of the second network device.
  • the reselection condition may include at least one of the following: the signal quality of the cell of the second network device is greater than the signal quality of the cell of the first network device, and the signal quality of the cell of the second network device is greater than or equal to the third signal quality threshold.
  • the third signal quality threshold may be preset, or may be obtained by the terminal device from the first network device.
  • SSB is used both for initial access and for cell handover or cell reselection. Therefore, the cell needs to frequently send SSB so that the terminal device can perform initial access, cell handover or cell reselection based on the SSB. In this way, the overhead of sending SSB is larger and the communication efficiency is lower. How to reduce the overhead of SSB and improve the efficiency of measuring SSB is a problem that needs to be solved in this application.
  • the embodiment of the present application provides a communication method, which can be applied to the communication system shown in Figure 3 or Figure 4. Referring to the flow chart shown in FIG. 7A , the flow of this method will be described in detail below.
  • the first cell sends the first SSB.
  • the first SSB is the SSB used for initial access.
  • the first SSB can be used for the initial random access procedure.
  • the first SSB can also be used for processes other than cell handover or cell reselection, such as beam failure recovery, uplink data transmission, or RRC connection re-establishment.
  • the first cell may be a cell within the coverage area of the first satellite, and the first satellite may cover at least one area.
  • the first cell may send the first SSB according to the configuration information of the first SSB (hereinafter referred to as the first configuration information).
  • the first configuration information may include at least one of the following:
  • the time domain length of the first SSB It can indicate the time length of the time domain resources occupied by the first SSB.
  • the time domain length of the first SSB is 4 orthogonal frequency division multiplexing (OFDM) symbols.
  • the sending cycle of the first SSB can indicate the cycle of sending the first SSB.
  • the transmission period of the first SSB may be 5 ms, 10 ms, 20 ms, 40 ms, 80 ms or 160 ms.
  • SSB bitmap (bitmap, also called bit indication) of the first SSB: can be used to indicate whether one or more SSBs exist. For example, assuming that there are at most 4 SSBs (for example, these 4 SSBs can be identified as SSB0, SSB1, SSB2 and SSB3), the 4 bits in the SSB bitmap correspond to the 4 SSBs one by one, and each bit is used for Indicates whether the corresponding SSB exists.
  • the value of a bit in the SSB bitmap is 0, it means that the corresponding SSB does not exist at a certain time period; when the value of a bit in the SSB bitmap is 1, it means that the corresponding SSB does not exist at a certain time period. segment exists. For example, when the SSB bitmap is 0011, it means that SSB0 and SSB1 do not exist in the current time period, and SSB2 and SSB3 exist in the current time period; when the SSB bitmap is 1011, it means that SSB0, SSB2, and SSB3 exist in the current time period, and SSB1 exists in the current time period. The current time period does not exist.
  • Measurement window configuration of the first SSB can be used to indicate multiple time windows in which the first SSB can be measured.
  • the measurement window configuration may include information indicating one of the plurality of time windows, and a time interval between every two adjacent time windows of the plurality of time windows. The time interval between each two adjacent time windows may be the same as the transmission period of the first SSB.
  • the measurement window configuration may include: start time information (for example, 0 ms) and end time information (for example, 5 ms) of the time window 1 capable of measuring the first SSB, and the time between each two adjacent time windows. time interval (for example, 20ms).
  • the measurement window configuration may include: the starting time information of time window 1 (for example, 0 ms) that can measure the first SSB, the time length occupied by time window 1 (for example, 5 ms), and every two adjacent The time interval between time windows (for example, 20ms).
  • the measurement window offset (offset) of the first SSB indicates the offset of the start time of the measurement window of the first SSB relative to the time reference point.
  • the time reference point can be a frame boundary or a system-defined time point.
  • the measurement window offset of the first SSB is 4 ms, which means that the start time of the measurement window of the first SSB is delayed by 4 ms at the frame boundary or a system-defined time point.
  • Reference location of the first SSB Indicates the projection position of the center point of the beam where the first SSB is located on the sphere (for example, longitude and latitude position or earth-centered earth-fixed (ECEF) coordinate system xyz coordinates below).
  • ECEF earth-centered earth-fixed
  • the first configuration information may be pre-set, determined for the first cell, or set for the first cell by other devices (eg, ground network devices).
  • the first configuration information may be updated in the same manner as the update mechanism of SIB1.
  • the update of SIB1 of the first cell may be triggered.
  • the first cell may explicitly or implicitly indicate that the first SSB is the SSB used for initial access.
  • the first SSB includes a first indication, and the first indication is used to indicate that the current SSB is the SSB used for initial access.
  • the first indication may be located in a first field of the first SSB. When the value of the first field is the first value, the current SSB is the SSB used for initial access. In this way, the terminal device can determine that the received SSB is the first SSB according to the first indication.
  • the first SSB contains first default parameters. In this way, the terminal device can determine that the received SSB is the first SSB based on the first default parameter.
  • the first SSB is carried on the first set frequency. In this way, the terminal device can determine that the received SSB is the first SSB according to the first set frequency carrying the first SSB.
  • the first cell sends a second SSB.
  • the terminal device receives the second SSB from the first cell.
  • the second SSB is an SSB specially used for cell handover or cell reselection. In this way, the terminal device that receives the second SSB can switch or reselect to the first cell according to the second SSB.
  • the first cell may send the second SSB according to the configuration information of the second SSB (hereinafter referred to as the second configuration information).
  • the second configuration information may include at least one of the following: the time domain length of the second SSB, the transmission cycle of the second SSB, the SSB bitmap of the second SSB, the measurement window configuration of the second SSB, and the measurement window of the second SSB. Offset, reference point position of the second SSB.
  • the second configuration information please refer to the description of the first configuration information, except that the first SSB is replaced with the second SSB, and repeated details will not be repeated.
  • the second configuration information may be preset, may be determined for the first cell, or may be set for the first cell by other equipment (for example, ground network equipment).
  • the first cell may indicate the second SSB explicitly or implicitly.
  • the second SSB includes a second indication, and the second indication is used to indicate that the current SSB is an SSB used for cell handover or cell reselection.
  • the second indication may be located in a second field of the second SSB.
  • the second SSB contains second default parameters. In this way, the terminal device can determine that the received SSB is the second SSB according to the second default parameter.
  • the second SSB is carried on the second set frequency. In this way, the terminal device can determine that the received SSB is the second SSB according to the second set frequency carrying the second SSB.
  • the first SSB is not used for cell switching or cell reselection, so that a terminal device receiving the first SSB will not switch or reselect to the first cell according to the first SSB.
  • the second SSB is not used for initial access, so that a terminal device receiving the second SSB will not initially access the first cell according to the second SSB.
  • the first SSB and the second SSB can be implemented by one of the following implementation methods:
  • Implementation method 1 The first SSB and the second SSB are both NR SSBs. That is to say, the first SSB and the second SSB can reuse the pattern of the NR SSB. This method can reuse the NR SSB pattern, which improves the usability of the solution and is easy to implement.
  • Implementation method 2 The first SSB is CD-SSB, and the second SSB is NCD-SSB.
  • the first SSB can reuse the pattern of the NR SSB, occupy the time window of the NR SSB, and use the sequence number of the NR SSB.
  • the second SSB does not occupy the time window of the NR SSB and does not use the sequence number of the NR SBB.
  • the time window length of NR SSB is 5ms
  • the maximum sequence number of NR SSB is 64.
  • the second SSB does not use the time window and sequence number of the NR SSB, which can expand more available SSBs and improve the efficiency of cell reselection and cell handover.
  • the second configuration information may also include a set of NCD-SSBs to be tested.
  • the set of NCD-SSBs to be tested may include sequence number information of the NCD-SSBs to be tested.
  • the NCD-SSB set to be tested includes one or more of ⁇ NCD-SSB0, NCD-SSB1,..., NCD-SSBM ⁇ .
  • M is the maximum number of NCD-SSBs supported by the network.
  • M can be 4, 8, 16, 32, or 64.
  • CD-SSBs and NCD-SSBs can be distinguished by at least one of the following:
  • the CD-SSB pattern is different from the NCD-SSB pattern. Therefore, the terminal device can determine whether the received SSB is CD-SSB or NCD-SSB based on the pattern.
  • SSB transmission cycle The transmission cycle of CD-SSB and the transmission cycle of NCD-SSB can be different. For example, the period of CD-SSB is 20ms and the period of NCD-SSB is 5s. Therefore, the terminal device can determine whether the received SSB is CD-SSB or NCD-SSB according to the SSB transmission cycle.
  • the MIB may include first type indication information used to indicate the SSB type, and the first type indication information may occupy 1 bit. For example, when the value of the first type indication information is 0, it means that the current SSB is CD-SSB; when the value of the first type indication information is 1, it means that the current SSB is NCD-SSB. In other possible ways, the MIB can also indicate the SSB type implicitly. For example, when the scrambling method of the MIB is the first scrambling method, it means that the current SSB is CD-SSB; when the scrambling method of the MIB is the second scrambling method, it means that the current SSB is NCD-SSB.
  • the first scrambling method and the second scrambling method are different.
  • the demodulation reference signal (DMRS) pattern corresponding to the MIB is the first pattern
  • the DMRS pattern corresponding to the MIB is the second pattern
  • the SSB is NCD-SSB.
  • the first pattern and the second pattern are different.
  • the PBCH payload may include second type indication information used to indicate the SSB type.
  • the second type indication information may occupy 1 bit. For example, when the value of the second type indication information is 0, it means that the current SSB is CD-SSB; when the value of the second type indication information is 1, it means that the current SSB is NCD-SSB.
  • the PBCH payload can also indicate the SSB type in an implicit way.
  • the scrambling method of the PBCH payload is the third scrambling method
  • it means that the current SSB is CD-SSB
  • the scrambling method of the PBCH payload is the fourth scrambling method
  • it means that the current SSB is NCD-SSB.
  • the third scrambling method and the fourth scrambling method are different.
  • the first cell may respectively send the first SSB for initial access and the second SSB for cell handover or cell reselection.
  • the first cell can send the first SSB; when the terminal device needs to switch or reselect to the first cell, the first cell can send the second SSB, so that it can be sent on demand.
  • SSB reduces the overhead of sending SSB and improves the efficiency of terminal equipment measuring SSB.
  • the first cell respectively sends the first SSB used for initial access and the second SSB used for cell handover or cell reselection.
  • the terminal device after receiving the second SSB, the terminal device performs cell switching or cell reselection based on the second SSB, thereby avoiding the inefficiency problem caused by relying solely on signal quality to trigger cell switching or cell reselection in NTN communications. This can improve the efficiency of cell reselection and cell handover.
  • the first cell may send the first SSB in the first area.
  • S701 includes S701a: the first cell sends the first SSB to the terminal device in the first area.
  • the first cell may transmit the second SSB within the second area.
  • S702 includes S702a: the first cell sends the second SSB to the terminal device in the second area.
  • the first area may be an area where the first cell sends data signals
  • the second area may be included in an area where the second cell sends data signals.
  • the second cell may be a cell within the coverage area of the second satellite, the first satellite and the second satellite are adjacent satellites, and the second satellite may cover at least one area.
  • the first cell of the first satellite can send data signals in wave positions 1 to 4; the second cell of the second satellite can send data signals in wave positions 5 to 8. Both the first satellite and the second satellite move to the right.
  • the first cell sends the first SSB in wave position 1 to wave position 4.
  • the first cell transmits the second SSB in wave position 5.
  • the first cell can send the first SSB used for initial access in the first area; and the second SSB used for cell handover or cell reselection in the second area.
  • the terminal equipment located in the second area can perform broadcast signal quality measurement and downlink synchronization according to the second SSB before the first cell covers the second area using the beam used to transmit the data signal, thereby
  • seamless reselection or handover to the first cell can be performed to improve the efficiency of cell reselection and cell handover.
  • the transmission time of the first SSB and the transmission time of the second SSB do not overlap.
  • the transmission time of the first SSB and the second SSB is time-divided.
  • the first SSB and the second SSB are both NR SSB
  • the first SSB and the second SSB are both located in the NR SSB burst, and the transmission time of the first SSB and the transmission time of the second SSB do not overlap.
  • FIG. 9 when the first SSB and the second SSB are both NR SSB, the first SSB and the second SSB are both located in the NR SSB burst, and the transmission time of the first SSB and the transmission time of the second SSB do not overlap.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB
  • the first SSB is located in the NR SSB burst
  • the second SSB is located outside the NR SSB burst.
  • the first SSB and the second SSB do not overlap in the time domain, so that the interference between the first SSB and the second SSB can be reduced.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • the transmission period of the first SSB is one of the following: 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms; the transmission period of the second SSB is several to several hundred seconds.
  • each NR SSB burst contains the first SSB, and some NR SSB bursts contain the second SSB. In this way, the second SSB
  • the transmission cycle of the SSB is greater than the transmission cycle of the first SSB.
  • the transmission cycle of the second SSB is cycle 2
  • the transmission cycle of the first SSB is cycle 1
  • cycle 2 is greater than Cycle 1.
  • the sending period of the first SSB is shorter than the sending period of the second SSB, thereby reducing the overhead of sending the second SSB.
  • the first random access opportunity (random access channel (RACH) occurrence, RO) associated with the first SSB is different from the second RO associated with the second SSB.
  • the first RO is an access opportunity associated with the first SSB, and the terminal device can perform access related to initial random access, beam recovery, or data transmission request in the first RO.
  • the second RO is the access opportunity associated with the second SSB, and the terminal device after group switching can access the second RO.
  • RO may represent the resources (such as time domain position and/or time length) occupied by sending random access preambles.
  • At least one of the following parameters of the first RO and the second RO is different:
  • Time domain cycle It can represent the cycle of RO resources in the time domain.
  • the first RO may be located after the associated first SSB, and the time domain period of the first RO may be the same as the transmission period of the first SSB; in the time domain, the first RO may be located after the associated first SSB.
  • the second RO may be located behind the associated second SSB, and the time domain period of the second RO may be the same as the transmission period of the second SSB.
  • the transmission cycle of the first SSB is cycle 1
  • the time domain cycle of the first RO is also cycle 1
  • the transmission cycle of the second SSB is cycle 2
  • the time domain cycle of the second RO is also cycle 2.
  • Duration It can represent the length of time corresponding to RO's time domain resources.
  • the time length corresponding to the time domain resource of the first RO is 3ms, that is, the duration of the first RO is 3ms
  • the time length corresponding to the time domain resource of the second RO is 10ms, that is, the duration of the second RO is 10ms.
  • Frequency domain position It can indicate the position of RO resources in the frequency domain.
  • the frequency domain position of the first RO and the frequency domain position of the second RO may partially overlap, or may not overlap.
  • Polarization mode It can represent the polarization mode corresponding to the RO, such as left-hand circular polarization, right-hand circular polarization, elliptical polarization or linear polarization, etc. Exemplarily, the polarization mode corresponding to the first RO is left-hand circular polarization, and the polarization mode corresponding to the second RO is right-hand circular polarization.
  • the terminal device may switch through process 1 below or reselect through process 2 below. This is described below respectively.
  • the method in process 1 will be described below with reference to Figure 12 .
  • the method includes:
  • the second cell sends the third SSB to the terminal device.
  • the terminal device receives the third SSB from the second cell.
  • the third SSB is the SSB used for initial access.
  • the third SSB can be used for the initial random access procedure.
  • the third SSB can also be used for processes other than cell handover or cell reselection, such as beam failure recovery, uplink data transmission or RRC connection re-establishment.
  • the second cell may be a cell of the second satellite.
  • the second cell may send the third SSB according to the configuration information of the third SSB (hereinafter referred to as the third configuration information).
  • the third configuration information may include at least one of the following: the time domain length of the third SSB, the period of the third SSB, the SSB bitmap of the third SSB, the measurement window configuration of the third SSB, and the measurement window offset of the third SSB. Move the reference point position of the third SSB.
  • the specific content of the third configuration information refer to the description of the first configuration information, except that the first SSB is replaced with the third SSB, and repeated details will not be repeated.
  • the third configuration information may be preset, may also be determined for the second cell, or may be set for the second cell by other equipment (for example, ground network equipment).
  • the second cell may explicitly or implicitly indicate that the third SSB is the SSB used for initial access.
  • the instruction method may refer to the description of "instructing the first SSB to be the SSB used for initial access" in S701, except that the first SSB is replaced by the third SSB, which will not be described again here.
  • the third SSB is not used for cell handover or cell reselection. In this way, the terminal equipment that receives the third SSB will not switch or reselect to the second cell based on the third SSB.
  • the terminal device accesses the second cell according to the third SSB.
  • the terminal device may be a terminal device in the second area.
  • the second area may be included in an area where the second cell sends data signals.
  • the specific content of the second region reference can be made to the description of the second region in the method shown in FIG. 7A and will not be described again here.
  • This application does not limit the specific process of the terminal device accessing the second cell according to the third SSB. After accessing the second cell, the terminal device is in a connected state.
  • the first cell sends a second SSB.
  • the terminal device receives the second SSB from the first cell.
  • the terminal device sends a measurement report to the second cell according to the second SSB.
  • the terminal device may determine the received signal quality of the first cell according to the second SSB.
  • the terminal device may send a measurement report to the second cell.
  • setting the reporting condition may include: the signal quality of the first cell is greater than the set signal quality threshold.
  • the measurement report may include: the sequence number of the second SSB and the signal strength of the first cell received by the terminal device.
  • the second cell may determine to switch the terminal equipment to the first cell, and switch the terminal equipment from the second cell to the first cell through the method shown in S605-S608.
  • the terminal equipment in the connected state can switch to the first cell according to the second SSB.
  • the efficiency of group switching can be improved.
  • step A1 the method shown in FIG12 further includes step A1:
  • A1 The terminal device obtains the second configuration information.
  • the second configuration information is used to instruct the first cell to send the configuration of the second SSB.
  • the second configuration information may include: the measurement window configuration of the second SSB, the measurement window offset of the second SSB, the reference point position of the second SSB, and the NCD-SSB to be measured. SSB collection.
  • the terminal device can obtain the second configuration information through one of the following methods:
  • Method 1 The terminal device receives the second configuration information broadcast by the first cell.
  • the first cell may send the second configuration information through a broadcast message, so that the terminal device obtains the second configuration information through the broadcast message from the first cell.
  • the execution order between steps A1 and S1201-S1202 is not limited.
  • Method 2 The terminal device may receive the second configuration information from the first cell forwarded by the second cell.
  • the second method may include steps B1-B2:
  • the first cell sends second configuration information to the second cell.
  • the first cell may send the configuration information to the second cell under at least one of the following conditions:
  • Case 1 The first cell initially determines that the first cell sends the configuration of the second SSB. At this time, the second configuration information sent by the first cell to the second cell is used to instruct the initially determined first cell to send the configuration of the second SSB.
  • Case 2 The first cell updates the configuration of the second SSB sent by the first cell.
  • the second configuration information sent by the first cell to the second cell is used to instruct the first cell to send the updated configuration of the second SSB.
  • the first cell does not update SIB1 of its own cell.
  • the second cell sends the second configuration information to the terminal device.
  • the terminal device receives the second configuration information from the second cell.
  • the second configuration information may be carried in an existing message or in a new message, which is not limited in this application.
  • step A1 can be executed after S1202.
  • S1203 may include: the terminal device receives the second SSB from the first cell according to the second configuration information.
  • the terminal device may receive the second SSB from the first cell within the time window indicated by the measurement window configuration.
  • the terminal device uses the period of the second SSB as a period to detect the second SSB from the first cell.
  • the second SSB is NCD-SSB.
  • the terminal device can select an appropriate initial NCD-SSB based on its own global navigation satellite system (GNSS) position and reference point position, and receive the initial NCD-SSB.
  • the terminal device may select the initial NCD-SSB based on the criterion of the closest distance between the terminal device position and the reference point position or the minimum angle between the terminal device position, the satellite position and the reference point position.
  • GNSS global navigation satellite system
  • the terminal device can receive the second SSB from the first cell according to the second configuration information, thereby avoiding blind detection of the second SSB by the terminal device, thereby reducing energy consumption of the terminal device.
  • the second cell sends a handover command to the terminal device.
  • the terminal device receives the handover command from the second cell.
  • the handover command may be used to instruct the terminal device to handover to the first cell.
  • the handover command may be the second RRC reconfiguration message in S608.
  • S608 For details, please refer to S608 and will not be described in detail here.
  • the terminal device receives the first SSB from the first cell.
  • the terminal device can blindly detect the first SSB from the first cell, and access the first cell according to the detected first SSB.
  • the terminal device may receive the first SSB from the first cell according to the received second SSB.
  • this method includes steps D1-D2:
  • the terminal device receives the first offset indication.
  • the first offset indication can be indicated by adding a ⁇ T field in the MIB, SIB1, RRC and other messages.
  • the first offset indication may also be indicated by reusing the parameter K_SSB in the existing protocol.
  • the reserved bits in parameter K_SSB contain the first offset indication.
  • the unit of the time offset indicated by the first offset indication may be a symbol, a time slot, a millisecond, a frame, etc.
  • the terminal device can receive the first offset indication in one of the following ways:
  • Method 1 The terminal device receives the first offset indication broadcast by the first cell.
  • the first cell may send the first offset indication through a broadcast message, so that the terminal device obtains the first offset indication through the broadcast message from the first cell.
  • the execution order between steps D1 and S1201-S1204 is not limited.
  • Method 2 The terminal device may receive the first offset indication from the first cell forwarded by the second cell.
  • Method 2 may include steps E1-E2:
  • E1 The first cell sends a first offset indication to the second cell.
  • the second cell receives the first offset indication from the first cell.
  • the first cell may send the first offset indication to the second cell through an interface between the first cell and the second cell.
  • the second cell sends the first offset indication to the terminal equipment.
  • the terminal device receives the first offset indication.
  • the first offset indication may be carried in an existing message or in a new message.
  • the terminal device receives the first SSB from the first cell according to the first offset indication and the time when the second SSB is received. For example, the time offset indicated by the first offset indication is ⁇ T. If in S1203, the terminal device receives the second SSB at time T3, the terminal device may receive the first SSB from the first cell at time T3+ ⁇ T. SSB.
  • Steps D1 and D2 will be described below by taking the first SSB as CD-SSB and the second SSB as NCD-SSB as an example.
  • the first cell may send NCD-SSB and CD-SSB on the same wave position successively. On the same wave position, there is a certain time domain offset between the transmission time of NCD-SSB and the transmission time of CD-SSB.
  • the beam containing NCD-SSB sent by the first cell can cover wave positions 5 and 7
  • the beam containing CD-SSB sent by the first satellite can cover wave positions 1-4.
  • the beam containing NCD-SSB sent by the first cell covers wave positions 6 and 8, and the beam containing CD-SSB sent by the first cell covers wave positions 2, 4, 5 and 7.
  • UE1 is located in wave position 5.
  • UE1 can measure the NCD-SSB from the first cell; at time T2, UE1 can measure the CD-SSB from the first cell. Since there is a certain time domain offset between the transmission time of NCD-SSB and the transmission time of CD-SSB, UE1 can determine the time when it is expected to receive CD-SSB based on the time when it receives NCD-SSB.
  • the terminal device can receive the first SSB from the first cell according to the first offset indication and the time when the second SSB is received, so that there is no need for the terminal device to blindly detect the first SSB, and there is no need for the second cell to report the first SSB to the terminal device.
  • Sending the configuration information of the first SSB can thereby reduce the energy consumption of the terminal device and reduce the cost of obtaining the configuration information of the first SSB.
  • the method shown in Figure 12 also includes step D1:
  • the terminal equipment communicates with the first cell using the resources for handover and/or the random access preamble for handover corresponding to the NCD-SSB.
  • NCD-SSB may correspond to resources used for handover and/or a random access preamble used for handover.
  • the corresponding relationship between the NCD-SSB and the resources used for handover and/or the random access preamble used for handover can be preset, or it can be a network device (for example, the first satellite or a network device located on the ground, etc.) definite.
  • the corresponding relationship can be saved in the terminal device.
  • the terminal device can obtain the corresponding relationship from the network device.
  • the terminal device may send a random access message to the first cell through the resource.
  • the terminal device may send the random access preamble corresponding to the NCD-SSB to the first cell.
  • NCD-SSB can be associated with dedicated handover resources and/or random access preamble for handover, which can be used for uplink random access during group handover, thereby improving the efficiency of group handover. Moreover, through NCD-SSB associated handover resources, the terminal device does not need to obtain resource configuration information for group handover, thereby reducing overhead. Through the random access preamble associated with NCD-SSB, the conflict between the random access preamble used for handover and the random access preamble used for initial access can be avoided, thereby improving the success rate of group handover.
  • the method in process 2 will be described below with reference to Figure 14 .
  • the method includes:
  • S1401 The terminal device receives a first offset indication.
  • the first offset indication is used to indicate a time offset between the transmission time of the second SSB and the transmission time of the first SSB adjacent to the second SSB.
  • the terminal device may be a terminal device in an idle state in the second area.
  • the second area may be included in an area where the second cell sends data signals.
  • reference may be made to the description of the second area in the method shown in FIG. 7A.
  • the first cell sends the second SSB.
  • the terminal device receives the second SSB from the first cell.
  • S1403 The terminal device reselects to the first cell based on the second SSB.
  • This application does not limit the process of reselecting the terminal device to the first cell based on the second SSB. For example, when the terminal device determines that the signal quality from the first cell is greater than the set signal quality threshold according to the second SSB, the terminal device may reselect to the first cell.
  • S1404 The terminal device receives the first SSB from the first cell according to the time when the second SSB is received and the first offset indication.
  • step D3 the specific content of S1404 can be referred to step D3, and repeated details will not be repeated.
  • the terminal device can search for SSB on the synchronization raster to be detected. If the terminal device determines that the received SSB is the first SSB based on the display or implicit method in S701, the terminal device can access and camp based on the first SSB.
  • the terminal equipment in the idle state can be reselected to the first cell according to the second SSB.
  • the efficiency of group reselection can be improved.
  • the terminal device can receive the first SSB from the first cell according to the first offset indication and the time when the second SSB is received, so that there is no need for the terminal device to blindly detect the first SSB and no need for the second cell to
  • the terminal device sends the configuration information of the first SSB, thereby reducing the energy consumption of the terminal device and reducing the cost of obtaining the configuration information of the first SSB.
  • the embodiment of the present application provides a communication method, which can be applied to the communication system shown in Figure 3 or Figure 4. Referring to the flow chart shown in Figure 15, the flow of this method will be described in detail below.
  • the first cell sends data signals and SSB in the third area.
  • the terminal equipment in the third area may receive the data signal and SSB from the first cell.
  • the first cell may be a cell within the coverage area of the first satellite, and the first satellite may cover at least one area.
  • time T4 belongs to the first time period.
  • the first cell sends data signals and SSB within wave position 1 to wave position 4.
  • the beam used to transmit the data signal and the beam used to transmit the SSB of the first cell may cover wave position 1 to wave position 4.
  • the beam used for transmitting data signals may be called a service beam.
  • the beam used to transmit SSB may be called a broadcast beam.
  • the second cell of the second satellite transmits data signals and SSB within wave position 5-wave position 8.
  • the service beam and broadcast beam of the second cell may cover wave position 5 to wave position 8.
  • the first satellite and the second satellite move to the right.
  • the SSB can be NR SSB or CD-SSB.
  • SSB can be used for both initial access and cell reselection or cell handover.
  • the beams of different satellites do not overlap at the wave position level.
  • the first cell sends data signals in the third area and sends SSB in the fourth area.
  • the terminal equipment in the third area can receive the data signal from the first cell
  • the terminal equipment in the fourth area can receive the SSB from the first cell.
  • the second time period is a time period after the first time period.
  • the first time period is 0 to 5 seconds (s)
  • the second time period is 6 to 11 s.
  • time T5 belongs to the second time period.
  • the first cell sends data signals within wave position 1 to wave position 4, and sends SSB within wave position 2, wave position 4, wave position 5, and wave position 7.
  • the second cell sends data signals in wave positions 5 to 8, and sends SSB in wave positions 6, 8, 9 and 10.
  • the terminal equipment in wave position 5 and wave position 7 can be switched or reselected to the first cell.
  • the first cell sends a data signal and SSB in the fourth area. Accordingly, in the third time period, the terminal device in the fourth area can receive the data signal and SSB from the first cell.
  • the third time period is the time period after the second time period.
  • the second time period is 6 to 11 seconds
  • the third time period is 12 to 17 seconds.
  • the starting time of the third time period may be the time when a set proportion of terminal equipment in the fourth area completes cell switching or cell reselection. This setting ratio is, for example, 1/3.
  • time T6 belongs to the third time period.
  • the first cell sends data signals and SSB in wave position 2, wave position 4, wave position 5 and wave position 7.
  • the second cell of the second satellite transmits data signals and SSB in wave position 6, wave position 8, wave position 9 and wave position 10.
  • the first cell can first send the SSB in the fourth area before sending the data signal in the fourth area.
  • the terminal equipment located in the fourth area can measure the broadcast signal quality and downlink synchronization according to the SSB before the first cell uses the beam for transmitting the data signal to cover the fourth area, so that it can
  • seamless reselection or handover to the first cell improves the efficiency of cell reselection and cell handover.
  • the terminal device can determine the corresponding relationship between the time when the first cell sends the signal and the area through implementation method 1 or implementation method 2.
  • Implementation method one the terminal device obtains the third configuration information and the fourth configuration information respectively.
  • the third configuration information is used to indicate the corresponding relationship between the time when the first satellite sends the data signal and the area;
  • the fourth configuration information is used to indicate the corresponding relationship between the time when the first satellite sends the SSB and the area.
  • the first implementation method may include steps F1-F4:
  • the first cell sends the third configuration information.
  • the terminal device receives the third configuration information.
  • the first cell directly sends the third configuration information to the terminal device. For example, if the terminal device is located at wave position 2, the first cell may send the third configuration information via a broadcast message, or send the third configuration information to the terminal device in a connected state via a unicast message.
  • the first cell may also send the third configuration information to the terminal device through other cells.
  • the terminal device is located at wave position 5, and the first cell forwards the third configuration information to the terminal device through the second cell of the second satellite.
  • the third configuration information may be used to indicate the corresponding relationship between the time and the area where the first satellite currently transmits the data signal.
  • the current time is time T4, and time T4 belongs to the first time period.
  • the third configuration information includes: indication information of the first time period and indication information of the third area. This means that during the first time period, the first cell can send data signals in the third area.
  • the information used to indicate the first time period may be specific time information, such as 0 to 5 seconds; the information used to indicate the first time period may also be the starting time and duration of the first time period, for example, start The time is 0 seconds and the duration is 5 seconds.
  • the indication information of the third area may be the identification of the third area or the identification of the wave position in the third area.
  • the third configuration information can also be used to indicate the correspondence between the time and area in which the first satellite sends data signals in the current and future periods.
  • the current time is moment T4, which belongs to the first time period
  • the third configuration information includes: indication information of the first time period and indication information of the third area, indication information of the second time period and indication information of the third area, indication information of the third time period and indication information of the fourth area.
  • the specific contents of the indication information of the second time period and the indication information of the third time period can refer to the description of the information used to indicate the first time period.
  • the indication information of the fourth area can refer to the description of the indication information of the third area.
  • the terminal device receives the data signal from the first cell according to the third configuration information.
  • the terminal device may receive the data signal from the first cell in the corresponding area within the time period indicated by the third configuration information.
  • the following description takes the third configuration information including: the indication information of the first time period and the indication information of the third area as an example. If the third configuration information received by the terminal device includes: the indication information of the first time period and the indication information of the third area, the terminal equipment can receive the data signal from the first cell in the third area within the first time period. .
  • the first cell sends the fourth configuration information.
  • the terminal device receives the fourth configuration information.
  • step F1 The way in which the terminal device receives the fourth configuration information can refer to step F1, except that the third configuration information is replaced with the fourth configuration information, and the data signal is replaced with SSB.
  • the fourth configuration information may be used to indicate the current correspondence between the time and area when the first satellite transmits the SSB.
  • the current time is time T4
  • time T4 belongs to the first time period
  • the fourth configuration information includes: indication information of the first time period and indication information of the third area. This means that during the first time period, the first cell can send SSB within the third area.
  • step F1 For information indicating the first time period and indication information for the third area, reference may be made to step F1, which will not be described again here.
  • the fourth configuration information may also be used to represent the corresponding relationship between the time and area when the first satellite transmits SSB currently and within a future period.
  • the current time is T4
  • T4 belongs to the first time period.
  • the fourth configuration information includes: indication information of the first time period and indication information of the third area, indication information of the second time period and indication of the fourth area. information, indication information for the third time period and indication information for the fourth area. This means that in the first time period, the first cell can send SSB in the third area, and in the second time period and the third time period, the first cell can send SSB in the fourth area.
  • the indication information of the second time period and the indication information of the third time period please refer to the description of the information used to indicate the first time period.
  • the indication information of the fourth area reference may be made to the description of the indication information of the third area.
  • the terminal device receives the SSB from the first cell according to the fourth configuration information.
  • the terminal device may receive the SSB from the first cell in the corresponding area within the time period indicated by the fourth configuration information.
  • the following description takes the fourth configuration information including: the indication information of the first time period and the indication information of the third area as an example. If the fourth configuration information received by the terminal device includes: indication information of the first time period and indication information of the third area, the terminal equipment may receive the SSB from the first cell in the third area within the first time period.
  • the terminal device may also determine the time during which the first cell can provide services for the terminal device (hereinafter referred to as service time) based on the third configuration information and the fourth configuration information. Outside service hours, the terminal device does not detect signals from the first cell.
  • the terminal device is located at wave position 5.
  • the third configuration information indicates that the first cell sends data signals at wave positions 1 to 4 from 0 to 5 seconds;
  • the fourth configuration information indicates that the first cell sends SSB from 0 to 5 seconds at wave positions 1 to 4.
  • SSB is sent at wave position 2, wave position 4, wave position 5 and wave position 7 in 6 to 11 seconds.
  • the terminal device can determine that the first cell does not provide services for the terminal device from 0 to 6 seconds, and during this time period, the terminal device does not detect the signal from the first cell. Through this method, the power consumption of the terminal device can be reduced.
  • Implementation manner two the terminal device obtains the fifth configuration information and the second offset indication.
  • the fifth configuration information is used to indicate the corresponding relationship between the time when the first satellite sends the first signal and the area;
  • the second offset indication is used to indicate the time when the first satellite sends the first signal in the third area or the fourth area. and the time when the second signal is sent.
  • the first signal is a data signal and the second signal is SSB; or, the first signal is SSB and the second signal is a data signal.
  • the second implementation may include steps G1-G4:
  • G1 The first cell sends the fifth configuration information.
  • the terminal device receives the fifth configuration information.
  • the fifth configuration information when the first signal is a data signal, the fifth configuration information may be the third configuration information in step F1, and step G1 may refer to step F1.
  • the fifth configuration information when the first signal is SSB, the fifth configuration information may be the fourth configuration information in step F3, and step G2 may refer to step F3.
  • G2 The terminal device receives the first signal from the first cell according to the fifth configuration information.
  • step G2 can refer to step F2.
  • step G2 can refer to step F4.
  • G3 The first cell sends the second offset indication.
  • the terminal device receives the second offset indication.
  • the first cell directly sends the second offset indication to the terminal equipment.
  • the first cell may send the second offset indication through a broadcast message, or send the second offset indication to the connected terminal device through a unicast message.
  • the first cell may also send the second offset indication to the terminal device through transmission by other cells.
  • the terminal device is located at wave position 5, and the first cell forwards the second offset indication to the terminal device through the second cell of the second satellite.
  • G4 The terminal device receives the second signal from the first cell according to the fifth configuration information and the second offset indication.
  • the fifth configuration information includes: indication information of the second time period and indication information of the fourth area. If the second time period is 6 to 11 seconds, and the time offset indicated by the second offset indication is 6 seconds, the terminal equipment can determine that the data signal from the first cell is received in the fourth area within 12 to 17 seconds.
  • the terminal device can determine the time to receive the second signal based on the configuration information of the first signal and the second offset indication without receiving the configuration information of the second signal, thereby reducing overhead.
  • the terminal device may also determine the time during which the first cell can provide services for the terminal device (hereinafter referred to as service time) based on the fifth configuration information and the second offset indication. Outside service hours, the terminal device does not detect signals from the first cell. Through this method, the power consumption of the terminal device can be reduced.
  • the method shown in Figure 15 also includes steps H1-H2:
  • the first cell sends indication information for the fourth time period.
  • the terminal device receives the indication information for the fourth time period.
  • the first transmitting beam of the first cell may be paired with the first receiving beam of the terminal device.
  • the fourth time period is a time period in which the first transmit beam and the first receive beam are paired.
  • the first cell may directly send the indication information of the fourth time period to the terminal device. For example, if the terminal device is located at wave position 2, the first cell may send the indication information of the fourth time period through a broadcast message, or send the indication information for the fourth time period to the connected terminal device through a unicast message.
  • the first cell may also send the indication information of the fourth time period to the terminal device through other cells.
  • the terminal device is located at wave position 5, and the first cell forwards the indication information of the fourth time period to the terminal device through the second cell of the second satellite.
  • the specific content of the instruction information of the fourth time period may refer to the instruction information of the first time period in step F1, except that the first time period is replaced by the fourth time period, which will not be described again here.
  • the terminal device may receive data signals and/or SSB from the first cell via the first receiving beam.
  • the terminal device receives the data signal and/or SSB from the first cell through the first receiving beam within the fourth time period indicated by the first cell.
  • the first receiving beam is paired with the first transmitting beam of the first cell. Therefore, the method can improve communication quality.
  • the terminal device does not need to detect which beam can be paired with the transmit beam of the first cell, thereby improving communication efficiency.
  • the embodiment of the present application provides a communication device through Figure 17, which can be used to perform the functions of the relevant steps in the above method embodiment.
  • the functions described can be implemented by hardware, or can be implemented by software or hardware executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the above functions.
  • the structure of the communication device is shown in Figure 17, including a communication unit 1701 and a processing unit 1702.
  • the communication device 1700 can be applied to network equipment, satellites or terminal equipment in the communication system shown in Figure 3 or Figure 4, and can implement the communication methods provided in the above embodiments and examples of the present application.
  • the functions of each unit in the communication device 1700 are introduced below.
  • the communication unit 1701 is used to receive and send data.
  • the communication unit 1701 can be implemented by a transceiver, for example, a mobile communication module.
  • the mobile communication module may include at least one antenna, at least one filter, switch, power amplifier, low noise amplifier (low noise amplifier, LNA), etc.
  • the processing unit 1702 may be used to support the communication device 1700 in performing the processing actions in the above method embodiment.
  • the processing unit 1702 may be implemented by a processor.
  • the processor can be a central processing unit (CPU), or other general-purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC) , field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • a general-purpose processor can be a microprocessor or any conventional processor.
  • the communication device 1700 is applied to network equipment or satellites in the communication system shown in Figure 3 or Figure 4 .
  • the specific functions of the processing unit 1702 in this embodiment will be introduced below.
  • the processing unit 1702 is configured to: send the first SSB through the communication unit 1701, the first SSB is the SSB used for initial access; send the second SSB through the communication unit 1701, the second SSB is used for the cell SSB for handover or cell reselection.
  • the first SSB is not used for cell handover or cell reselection, and the second SSB is not used for initial access.
  • the processing unit 1702 is specifically configured to: send the first SSB in the first area through the communication unit 1701; send the second SSB in the second area through the communication unit 1701.
  • the processing unit 1702 is specifically configured to send configuration information to the second cell through the communication unit 1701, where the configuration information is used to instruct the first cell to send the configuration of the second SSB.
  • the sending time of the first SSB and the sending time of the second SSB do not overlap.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • both the first SSB and the second SSB are NR SSB.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • NCD-SSB corresponds to resources used for handover and/or random access preamble used for handover.
  • the processing unit 1702 is specifically used to: send a first offset indication to the second cell through the communication unit 1701, and the first offset indication is used to indicate the time offset between the sending time of the second SSB and the sending time of the first SSB adjacent to the second SSB.
  • the processing unit 1702 is specifically configured to update the configuration of the first cell to send the second SSB without updating the system information block SIB of the first cell.
  • the communication device 1700 is applied to the terminal equipment in the communication system shown in Figure 3 or Figure 4 .
  • the specific functions of the processing unit 1702 in this embodiment will be introduced below.
  • the processing unit 1702 is used to: receive a third SSB from the second cell through the communication unit 1701, where the third SSB is an SSB used for initial access; access the second cell according to the third SSB; receive a second SSB from the first cell through the communication unit 1701, where the second SSB is an SSB used for cell switching or cell reselection; and send a measurement report to the second cell according to the second SSB through the communication unit 1701.
  • the processing unit 1702 is specifically configured to: receive configuration information from the second cell through the communication unit 1701, where the configuration information is used to instruct the first cell to send the configuration of the second SSB; according to the configuration information, through the The communication unit 1701 receives the second SSB from the first cell.
  • the second SSB is NCD-SSB
  • the processing unit 1702 is specifically configured to: use the resources for handover corresponding to the NCD-SSB and/or the random access preamble for handover through the communication unit 1701 , communicate with the first cell.
  • the processing unit 1702 is specifically configured to: receive a switching command from the second cell through the communication unit 1701, where the switching command is used to instruct the terminal device to switch to the first cell; receive a switching command from the second cell through the communication unit 1701.
  • the first SSB of a cell, the first SSB is the SSB used for initial access.
  • the processing unit 1702 is specifically configured to: receive a first offset indication through the communication unit 1701, where the first offset indication is used to indicate the sending time of the second SSB and the first offset adjacent to the second SSB.
  • the time interval between the sending times of SSB; the first SSB from the first cell is received through the communication unit 1701 according to the first offset indication and the time when the second SSB is received.
  • the first SSB is not used for cell handover or cell reselection, and the second SSB is not used for initial access.
  • the sending time of the first SSB and the sending time of the second SSB do not overlap.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • both the first SSB and the second SSB are NR SSB.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • the communication device 1700 is applied to a terminal device in the communication system shown in Figure 3 or Figure 4 .
  • the specific functions of the processing unit 1702 in this embodiment will be introduced below.
  • the processing unit 1702 is configured to: receive the second SSB from the first cell through the communication unit 1701, where the second SSB is the SSB used for cell switching or cell reselection; receive the first bias through the communication unit 1701. Shift indication.
  • the first offset indication is used to indicate the time offset between the sending time of the second SSB and the sending time of the first SSB adjacent to the second SSB.
  • the first SSB is the SSB used for initial access. ; According to the second SSB, reselect to the first cell; according to the time when the second SSB is received and the first offset indication, receive the first SSB from the first cell through the communication unit 1701.
  • the first SSB is not used for cell handover or cell reselection, and the second SSB is not used for initial access.
  • the sending time of the first SSB and the sending time of the second SSB do not overlap.
  • the transmission period of the first SSB is smaller than the transmission period of the second SSB.
  • both the first SSB and the second SSB are NR SSB.
  • the first SSB is CD-SSB and the second SSB is NCD-SSB.
  • each function in each embodiment of the present application can be integrated into one processing unit, or they can exist physically alone, or two or more units can be integrated into one unit.
  • the above integrated units can be implemented in the form of hardware or software functional units.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium.
  • the technical solution of the present application is essentially or contributes to the existing technology, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to cause a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in various embodiments of the application.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program code. .
  • the embodiment of the present application provides a communication device as shown in Figure 18, which can be used to perform relevant steps in the above method embodiment.
  • the communication device can be applied to network equipment, satellites or terminal equipment in the communication system shown in Figure 3 or Figure 4, and can implement the communication methods provided in the above embodiments and examples of the present application, with the communication device shown in Figure 17 Function.
  • the communication device 1800 includes: a communication module 1801 , a processor 1802 and a memory 1803 . Wherein, the communication module 1801, the processor 1802 and the memory 1803 are connected to each other.
  • the communication module 1801, the processor 1802 and the memory 1803 are connected to each other through a bus 1804.
  • the bus 1804 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc.
  • PCI peripheral component interconnect
  • EISA extended industry standard architecture
  • the bus can be divided into address bus, data bus, control bus, etc. For ease of presentation, only one thick line is used in Figure 18, but it does not mean that there is only one bus or one type of bus.
  • the communication module 1801 is used to receive and send data to implement communication interaction with other devices.
  • the communication module 1801 can be implemented through a physical interface, a communication module, a communication interface, and an input and output interface.
  • the processor 1802 may be configured to support the communication device 1800 in performing the processing actions in the above method embodiments. When the communication device 1800 is used to implement the above method embodiment, the processor 1802 may also be used to implement the functions of the above processing unit 1702.
  • the processor 1802 may be a CPU, or other general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, transistor logic device, hardware component or any combination thereof.
  • a general-purpose processor can be a microprocessor or any conventional processor.
  • the communication device 1800 is applied to a network device or a satellite in the communication system shown in FIG3 or 4.
  • the processor 1802 is specifically configured to: send a first SSB through the communication module 1801, where the first SSB is an SSB for initial access; send a second SSB through the communication module 1801, where the second SSB is an SSB for cell switching or cell reselection.
  • the communication device 1800 is applied to the terminal equipment in the communication system shown in Figure 3 or Figure 4.
  • the processor 1802 is specifically configured to: receive the third SSB from the second cell through the communication module 1801, where the third SSB is the SSB used for initial access; access the second cell according to the third SSB;
  • the communication module 1801 receives the second SSB from the first cell, and the second SSB is the SSB used for cell switching or cell reselection; the communication module 1801 sends a measurement report to the second cell according to the second SSB.
  • the communication device 1800 is applied to a terminal device in the communication system shown in FIG3 or 4.
  • the processor 1802 is specifically used to: receive a second SSB from the first cell through the communication module 1801, the second SSB is an SSB used for cell switching or cell reselection; receive a first offset indication through the communication module 1801, the first offset indication is used to indicate the time offset between the transmission time of the second SSB and the transmission time of the first SSB adjacent to the second SSB, the first SSB is an SSB used for initial access; reselect to the first cell according to the second SSB; receive the first SSB from the first cell through the communication module 1801 according to the time when the second SSB is received and the first offset indication.
  • processor 1802 For the specific functions of the processor 1802, please refer to the description of the communication method provided in the above embodiments of the present application and examples, as well as the specific functional description of the communication device 1700 in the embodiment of the present application shown in Figure 17, which will not be repeated here. Repeat.
  • the memory 1803 is used to store program instructions and data.
  • program instructions may include program code including computer operating instructions.
  • the memory 1803 may include RAM, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.
  • the processor 1802 executes the program instructions stored in the memory 1803, and uses the data stored in the memory 1803 to implement the above functions, thereby realizing the above communication method provided by the embodiment of the present application.
  • the memory 1803 in Figure 18 of this application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories.
  • the non-volatile memory can be ROM, programmable ROM (PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electrically erasable programmable read-only memory (Electrically EPROM) ,EEPROM) or flash memory.
  • Volatile memory can be RAM, which acts as an external cache.
  • RAM static random access memory
  • DRAM dynamic random access memory
  • DRAM synchronous dynamic random access memory
  • SDRAM double data rate synchronous dynamic random access memory
  • Double Data Rate SDRAM DDR SDRAM
  • enhanced SDRAM ESDRAM
  • Synchlink DRAM SLDRAM
  • Direct Rambus RAM Direct Rambus RAM
  • embodiments of the present application also provide a computer program, which when the computer program is run on a computer, causes the computer to execute the method provided in the above embodiments.
  • embodiments of the present application also provide a computer-readable storage medium.
  • the computer-readable storage medium stores a computer program.
  • the computer program When the computer program is executed by a computer, it causes the computer to execute the method provided in the above embodiments. .
  • the storage medium may be any available medium that can be accessed by the computer. Taking this as an example but not limited to: computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or can be used to carry or store instructions or data structures. Any other medium that contains the desired program code and is capable of being accessed by a computer.
  • an embodiment of the present application further provides a chip, which is used to read a computer program stored in a memory to implement the method provided in the above embodiments.
  • the chip system includes a processor and is used to support the computer device to implement the functions involved in each device in the above embodiments.
  • the chip system further includes a memory, and the memory is used to store necessary programs and data of the computer device.
  • the chip system may be composed of chips, or may include chips and other discrete devices.
  • the first cell can send the first SSB, and the first SSB is the SSB used for initial access.
  • the first cell may also send a second SSB, which is the SSB used for cell handover or cell reselection.
  • the first cell can respectively send the first SSB for initial access and the second SSB for cell handover or cell reselection.
  • the terminal device needs to access the first cell
  • the first cell can send the first SSB; when the terminal device needs to switch or reselect to the first cell, the first cell can send the second SSB, so that it can be sent on demand.
  • SSB reduces the overhead of sending SSB and improves the efficiency of terminal equipment measuring SSB.
  • embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment that combines software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory that causes a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction means, the instructions
  • the device implements the functions specified in a process or processes of the flowchart and/or a block or blocks of the block diagram.
  • These computer program instructions may also be loaded onto a computer or other programmable data processing device, causing a series of operating steps to be performed on the computer or other programmable device to produce computer-implemented processing, thereby executing on the computer or other programmable device.
  • Instructions provide steps for implementing the functions specified in a process or processes of a flowchart diagram and/or a block or blocks of a block diagram.

Abstract

本申请公开了一种通信方法及装置，该方法包括：第一小区可发送第一SSB，第一SSB为用于初始接入的SSB。第一小区还可发送第二SSB，第二SSB为用于小区切换或小区重选的SSB。通过该方法，第一小区可分别发送用于初始接入的第一SSB和用于小区切换或小区重选的第二SSB。这样，当需要终端设备接入第一小区时，第一小区可发送第一SSB；当需要终端设备切换或重选到第一小区时，第一小区可发送第二SSB，从而可按需发送SSB，降低发送SSB的开销，提高终端设备测量SSB的效率。

Description

通信方法及装置 技术领域
本申请涉及通信技术领域，尤其涉及一种通信方法及装置。
背景技术
随着非地面网络(non terrestrial networks，NTN)的发展，卫星网络的规模越来越大。例如，卫星网络从铱星星座的66颗发展到一网星座的720颗，并延展到12000+的星链(Starlink)超密低地球轨道(low earth orbit，LEO)卫星星座。
一颗卫星的覆盖范围可达几千甚至几万千米，而一个波束的覆盖范围可达几十米甚至几千米。为了支持卫星的广域覆盖，一颗卫星通常要配置几十、几百、甚至更多波束。为缓解单颗卫星载荷小和覆盖范围广的矛盾，可以采用跳波束的方式进行区域覆盖。即一颗卫星可以配置较多的波束覆盖较广的区域，但在同一时刻只使用较少数量的波束进行区域覆盖，通过在不同时刻使用的多个波束覆盖较广的区域。例如，如图1所示，一颗卫星配置了16个波束来覆盖较广的区域，但在一个时刻只使用4个波束进行区域覆盖。在T1时刻中，使用编号为0、1、4、5的四个波束进行区域覆盖；在T2时刻中，使用编号为2、3、6、7四个波束进行区域覆盖。以此类推，通过T1、T2、T3、T4分时的方式服务单星覆盖的所有区域(即16个波束对应的区域)。
当卫星采用跳波束的方式进行区域覆盖时，一个或多个波束覆盖的区域内的终端设备可能均需要进行频繁的小区切换或小区重选。在进行小区切换或重选时，终端设备需要测量目标小区的SSB。如何提高测量SSB的效率，是需要解决的问题。
发明内容
本申请提供一种通信方法及装置，用以提高测量SSB的效率。
第一方面，本申请实施例提供了一种通信方法。该方法包括：第一小区可发送第一SSB，第一SSB为用于初始接入的SSB。第一小区还可发送第二SSB，第二SSB为用于小区切换或小区重选的SSB。
可选的，第一SSB不用于小区切换或小区重选，这样，接收到第一SSB的终端设备不会根据第一SSB切换或重选到第一小区。第二SSB不用于初始接入，这样，接收到第二SSB的终端设备不会根据第二SSB初始接入到第一小区。
通过该方法，第一小区可分别发送用于初始接入的第一SSB和用于小区切换或小区重选的第二SSB。这样，当需要终端设备接入第一小区时，第一小区可发送第一SSB；当需要终端设备切换或重选到第一小区时，第一小区可发送第二SSB，从而可按需发送SSB，降低发送SSB的开销，提高终端设备测量SSB的效率。
在一种可能的设计中，第一小区可在第一区域内发送第一SSB，在第二区域内发送第二SSB。示例性的，其中，第一区域可为第一小区发送数据信号的区域，第二区域可包含在第二小区发送数据信号的区域中。通过该设计，第一小区可在第一区域内发送用于初始接入的第一SSB，在第二区域内发送用于小区切换或小区重选的第二SSB。这样，在跳波束系统中，位于第二区域内的终端设备可在第一小区使用用于发送数据信号的波束覆盖第 二区域之前，根据第二SSB进行广播信号质量的测量和下行同步，从而可在第一小区使用用于发送数据信号的波束覆盖第二区域时，无缝重选或切换至第一小区，提高小区重选和小区切换的效率。
在一种可能的设计中，第一小区还可向第二小区发送配置信息，该配置信息可用于指示第一小区发送第二SSB的配置。然后，第二小区可向第二小区内的终端设备发送该配置信息。通过该设计，第一小区可向其他小区(例如，第一小区的邻小区)发送用于指示第一小区发送第二SSB的配置。这样，其他小区内的终端设备可根据该配置信息接收第二SSB，从而可避免终端设备盲检测第二SSB，进而可降低终端设备的能耗。
在一种可能的设计中，第一SSB的发送时间和第二SSB的发送时间不重叠。换句话说，第一SSB和第二SSB的发送时间是时分的。通过该设计，第一SSB和第二SSB在时域上不重叠，从而可降低第一SSB和第二SSB之间的干扰。
在一种可能的设计中，第一SSB的发送周期小于第二SSB的发送周期。示例性的，第一SSB的发送周期为以下之一：5ms、10ms、20ms、40ms、80ms、160ms；第二SSB的发送周期为几～几百秒。通过该设计，第一SSB的发送周期小于第二SSB的发送周期，从而可降低发送第二SSB的开销。
在一种可能的设计中，第一SSB和第二SSB均为NR SSB。也就是说，第一SSB和第二SSB可复用NR SSB的图样。该设计可复用NR SSB的图样，提高了方案的可用性，易于实现。
在一种可能的设计中，第一SSB为CD-SSB，第二SSB为NCD-SSB。此时，第一SSB可复用NR SSB的图样，占用NR SSB的时间窗，并使用NR SSB的序号。第二SSB可不占用NR SSB的时间窗，不使用NR SBB的序号。该设计中，第二SSB不使用NR SSB的时间窗和序号，从而可扩展出更多可用的SSB，提高小区重选和小区切换的效率。
在一种可能的设计中，NCD-SSB与用于切换的资源和/或用于切换的随机接入前导对应。其中，NCD-SSB与用于切换的资源和/或用于切换的随机接入前导之间的对应关系可以是预先设置的，也可以是网络设备(例如，第一卫星或位于地面的网络设备等)确定的。通过该设计，NCD-SSB可关联专用的切换资源和/或用于切换的随机接入前导，用于群切换时的上行随机接入，从而可提高群切换的效率。并且，通过NCD-SSB关联的切换资源，终端设备无需获取用于群切换的资源配置信息，从而可降低开销。通过NCD-SSB关联的随机接入前导，可避免用于切换的随机接入前导与用于初始接入的随机接入前导之间的冲突进而提高群切换的成功率。
在一种可能的设计中，第一小区可向第二小区发送第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量。然后，第二小区可向第二小区内的终端设备发送第一偏移指示。通过该设计，终端设备可根据第一偏移指示和接收到第二SSB的时间，接收来自第一小区的第一SSB，从而无需终端设备盲检测第一SSB，也无需第二小区向终端设备发送第一SSB的配置信息，进而可降低终端设备的能耗，降低获取第一SSB的配置信息的开销。
在一种可能的设计中，第一小区还可更新第一小区发送第二SSB的配置，但不更新第一小区的SIB。通过该设计，在更新第一小区发送第二SSB的配置时，第一小区不更新第一小区的SIB，从而可降低更新SIB所需的开销。
第二方面，本申请实施例提供了一种通信方法。该方法包括：终端设备在接收来自第 二小区的第三SSB后，可根据第三SSB接入到第二小区。其中，第三SSB为用于初始接入的SSB。此时，终端设备可处于连接态。终端设备在接收来自第一小区的第二SSB后，可根据第二SSB向第二小区发送测量报告。其中，第二SSB为用于小区切换或小区重选的SSB。
通过该方法，处于连接态的终端设备可根据第二SSB切换到第一小区。当第二区域内的连接态终端设备均通过该方法切换到第一小区时，可提高群切换的效率。
在一种可能的设计中，终端设备还可接收来自第二小区的配置信息，并根据配置信息接收来自第一小区的第二SSB。其中，配置信息用于指示第一小区发送第二SSB的配置。通过该设计，终端设备可根据第二配置信息接收来自第一小区的第二SSB，从而可避免终端设备盲检测第二SSB，进而可降低终端设备的能耗。
在一种可能的设计中，第二SSB为NCD-SSB。终端设备可使用与NCD-SSB对应的用于切换的资源和/或用于切换的随机接入前导，与第一小区进行通信。其中，NCD-SSB与用于切换的资源和/或用于切换的随机接入前导之间的对应关系可以是预先设置的，也可以是网络设备(例如，第一卫星或位于地面的网络设备等)确定的。通过该设计，NCD-SSB可关联专用的切换资源和/或用于切换的随机接入前导，用于群切换时的上行随机接入，从而可提高群切换的效率。并且，通过NCD-SSB关联的切换资源，终端设备无需获取用于群切换的资源配置信息，从而可降低开销。通过NCD-SSB关联的随机接入前导，可避免用于切换的随机接入前导与用于初始接入的随机接入前导之间的冲突进而提高群切换的成功率。
在一种可能的设计中，终端设备可接收来自第二小区的切换命令，该切换命令用于指示终端设备切换到第一小区。然后，终端设备可接收来自第一小区的第一SSB，第一SSB为用于初始接入的SSB。通过该设计，终端设备可接收到来自第二小区的切换命令后，及时接收来自第一小区的第一SSB。
在一种可能的设计中，终端设备可接收第一偏移指示，并根据第一偏移指示和接收到第二SSB的时间，接收来自第一小区的第一SSB。其中，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间间隔。通过该设计，终端设备可根据第一偏移指示和接收到第二SSB的时间，接收来自第一小区的第一SSB，从而无需终端设备盲检测第一SSB，也无需第二小区向终端设备发送第一SSB的配置信息，进而可降低终端设备的能耗，降低获取第一SSB的配置信息的开销。
在一种可能的设计中，第一SSB不用于小区切换或小区重选，这样，接收到第一SSB的终端设备不会根据第一SSB切换或重选到第一小区。第二SSB不用于初始接入，这样，接收到第二SSB的终端设备不会根据第二SSB初始接入到第一小区。
在一种可能的设计中，第一SSB的发送时间和第二SSB的发送时间不重叠。换句话说，第一SSB和第二SSB的发送时间是时分的。通过该设计，第一SSB和第二SSB在时域上不重叠，从而可降低第一SSB和第二SSB之间的干扰。
在一种可能的设计中，第一SSB的发送周期小于第二SSB的发送周期。示例性的，第一SSB的发送周期为以下之一：5ms、10ms、20ms、40ms、80ms、160ms；第二SSB的发送周期为几～几百秒。通过该设计，第一SSB的发送周期小于第二SSB的发送周期，从而可降低发送第二SSB的开销。
在一种可能的设计中，第一SSB和第二SSB均为NR SSB。也就是说，第一SSB和 第二SSB可复用NR SSB的图样。该设计可复用NR SSB的图样，提高了方案的可用性，易于实现。
在一种可能的设计中，第一SSB为CD-SSB，第二SSB为NCD-SSB。此时，第一SSB可复用NR SSB的图样，占用NR SSB的时间窗，并使用NR SSB的序号。第二SSB可不占用NR SSB的时间窗，不使用NR SBB的序号。该设计中，第二SSB不使用NR SSB的时间窗和序号，从而可扩展出更多可用的SSB，提高小区重选和小区切换的效率。
第三方面，本申请实施例提供了一种通信方法。该方法包括：终端设备接收来自第一小区的第二同步信号块SSB，第二SSB为用于小区切换或小区重选的SSB。终端设备还可接收第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量，第一SSB为用于初始接入的SSB。终端设备在根据第二SSB重选到第一小区后，可根据接收到第二SSB的时间和第一偏移指示接收来自第一小区的第一SSB。
通过该方法，处于空闲态的终端设备可根据第二SSB重选到第一小区。当第二区域内的空闲态终端设备均通过该方法重选到第一小区时，可提高群重选的效率。
在一种可能的设计中，第一SSB不用于小区切换或小区重选，这样，接收到第一SSB的终端设备不会根据第一SSB切换或重选到第一小区。第二SSB不用于初始接入，这样，接收到第二SSB的终端设备不会根据第二SSB初始接入到第一小区。
在一种可能的设计中，第一SSB的发送时间和第二SSB的发送时间不重叠。换句话说，第一SSB和第二SSB的发送时间是时分的。通过该设计，第一SSB和第二SSB在时域上不重叠，从而可降低第一SSB和第二SSB之间的干扰。
在一种可能的设计中，第一SSB的发送周期小于第二SSB的发送周期。示例性的，第一SSB的发送周期为以下之一：5ms、10ms、20ms、40ms、80ms、160ms；第二SSB的发送周期为几～几百秒。通过该设计，第一SSB的发送周期小于第二SSB的发送周期，从而可降低发送第二SSB的开销。
在一种可能的设计中，第一SSB和第二SSB均为NR SSB。也就是说，第一SSB和第二SSB可复用NR SSB的图样。该设计可复用NR SSB的图样，提高了方案的可用性，易于实现。
在一种可能的设计中，第一SSB为CD-SSB，第二SSB为NCD-SSB。此时，第一SSB可复用NR SSB的图样，占用NR SSB的时间窗，并使用NR SSB的序号。第二SSB可不占用NR SSB的时间窗，不使用NR SBB的序号。该设计中，第二SSB不使用NR SSB的时间窗和序号，从而可扩展出更多可用的SSB，提高小区重选和小区切换的效率。
第四方面，本申请实施例提供了一种通信装置，包括用于执行以上任一方面中各个步骤的单元。
第五方面，本申请实施例提供了一种通信装置，包括至少一个处理元件和至少一个存储元件，其中该至少一个存储元件用于存储程序和数据，该至少一个处理元件用于读取并执行存储元件存储的程序和数据，以使得本申请以上任一方面提供的方法被实现。
第六方面，本申请实施例提供了一种通信系统，包括：用于执行第一方面提供的方法的第一小区，用于执行第二方面或第三方面提供的方法的终端设备。
第七方面，本申请实施例还提供了一种计算机程序，当所述计算机程序在计算机上运行时，使得所述计算机执行上述任一方面提供的方法。
第八方面，本申请实施例还提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有计算机程序，当所述计算机程序被计算机执行时，使得所述计算机执行上述任一方面提供的方法。
第九方面，本申请实施例还提供了一种芯片，所述芯片用于读取存储器中存储的计算机程序，执行上述任一方面提供的方法。
第十方面，本申请实施例还提供了一种芯片系统，该芯片系统包括处理器，用于支持计算机装置实现上述任一方面提供的方法。在一种可能的设计中，所述芯片系统还包括存储器，所述存储器用于保存该计算机装置必要的程序和数据。该芯片系统可以由芯片构成，也可以包含芯片和其他分立器件。
上述第四方面至第十方面中任一方面可以达到的技术效果可以参照上述第一方面至第三方面中任一方面中任一种可能设计可以达到的技术效果说明，重复之处不予论述。
附图说明
图1为本申请实施例中跳波束通信过程示意图；
图2A为本申请实施例中的一种透传模式的应用场景示意图；
图2B为本申请实施例中的一种非透传模式的应用场景示意图；
图3为本申请实施例中的一种移动通信系统的架构示意图；
图4为本申请实施例中的另一种移动通信系统的架构示意图；
图5为本申请实施例中小区定义的同步信号块(synchronization signal block，SSB)(cell defining SSB，CD-SSB)和非小区定义的SSB(Non-cell defining SSB，NCD-SSB)的示意图；
图6为一种切换方法的流程图；
图7A为本申请实施例中的一种通信方法的流程图；
图7B为本申请实施例中的一种通信方法的一种可能的实现方式的流程图；
图8为本申请实施例中的一种SSB和波位的映射关系的示意图；
图9为本申请实施例中的一种第一SSB和第二SSB的时域位置的示意图；
图10为本申请实施例中的另一种第一SSB和第二SSB的时域位置的示意图；
图11为本申请实施例中的第一RO和第二RO的位置的示意图；
图12为本申请实施例中的另一种通信方法的流程图；
图13为本申请实施例中第一卫星在不同时刻的覆盖区域示意图；
图14为本申请实施例中的又一种通信方法的流程图；
图15为本申请实施例中的再一种通信方法的流程图；
图16为本申请实施例中第一卫星和第二卫星在不同时刻的覆盖区域示意图；
图17为本申请实施例提供的一种通信装置的结构图；
图18为本申请实施例提供的另一种通信装置的结构图。
具体实施方式
本申请实施例提供一种通信方法及装置，其中，方法和装置是基于同一技术构思的，由于方法及装置解决问题的原理相似，因此装置与方法的实施可以相互参见，重复之处不 再赘述。
以下，对本申请中的部分用语进行解释说明，以便于本领域技术人员理解。
1)、通信装置，泛指具有通信功能的装置。示例性的，所述通信装置可以但不限于为终端设备、网络设备、中继设备、地面站设备等。
2)、网络设备，是移动通信系统中将终端设备接入到无线网络的设备。网络设备作为无线接入网中的节点，还可以称为基站、无线接入网(radio access network，RAN)节点(或设备)、接入点(access point，AP)、接入网(access network，AN)设备。
目前，一些网络设备的举例为：新一代节点B(generation Node B，gNB)、传输接收点(transmission reception point，TRP)、演进型节点B(evolved Node B，eNB)、无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station，BTS)、无线中继节点、无线回传节点、传输点(transmitting point，TP)、移动交换中心或家庭基站(例如，home evolved NodeB，或home Node B，HNB)。网络设备还可为基站的一个或一组天线面板。此外，网络设备还可以为构成gNB或TP的网络节点，例如，基带单元(base band unit，BBU)或分布式单元(distributed unit，DU)等。网络设备还可以是设备到设备(device-to-device，D2D)通信系统、机器到机器(machine to machine，M2M)通信系统、物联网(Internet of Things，IoT)、车联网通信系统或者其他通信系统中承担网络侧功能的设备。
3)、终端设备，是一种向用户提供语音和/或数据连通性的设备。终端设备又可以称为用户设备(user equipment，UE)、终端(terminal)、接入终端、终端单元、终端站、用户单元、用户站、移动台(mobile station，MS)、远方站、远程终端、移动终端(mobile terminal，MT)、无线通信设备、用户终端设备(customer premise equipment，CPE)、无线通信设备、用户代理、用户装置或终端代理等。
例如，终端设备可以为具有无线连接功能的手持式设备，也可以是具有通信功能的车辆、车载设备(如车载通信装置，车载通信芯片)、可穿戴设备、计算设备或连接到无线调制解调器的其它处理设备等。目前，一些终端设备的举例为：手机(mobile phone)、卫星电话、蜂窝电话、无绳电话、会话启动协议(session initiation protocol，SIP)电话、无线数据卡、无线调制解调器、机器类型通信设备、无线本地环路(wireless local loop，WLL)站、个人数字处理(personal digital assistant，PDA)设备、平板电脑、带无线收发功能的电脑、笔记本电脑、掌上电脑、移动互联网设备(mobile internet device，MID)、可穿戴设备，虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程手术(remote medical surgery)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等。
4)、地面站设备，是一种设置在地面且能与NTN系统中的NTN设备进行通信的设备。地面站设备例如为核心网(core network，CN)设备。CN设备是移动通信系统中CN部分中包含的网元。CN设备能够将终端设备接入到不同的数据网络，以及进行认证、计费、移动性管理、会话管理、策略控制、用户面转发等业务。CN设备可为目前的移动通信系统(如第5代(5 th generation，5G)移动通信系统)中的CN设备，也可为未来移动通信系统中的CN设备。在不同制式的移动通信系统中，具有相同功能的CN设备的名称可以 存在差异。然而，本申请实施例不限定具有每个功能的CN设备的具体名称。
例如，在第4代(4 th generation，4G)移动通信系统(即长期演进(long term evolution，LTE)中，负责接入控制、安全控制和信令协调等功能的网元为移动性管理实体(Mobile management entity，MME)；作为本地移动管理锚点的网元为服务网关(serving gateway，S-GW)；作为外部数据网络的切换的锚点、负责因特网协议(internet protocol，IP)地址分配的网元为分组数据网络(packet data network，PDN)网关(PDN gateway，P-GW)；存储用户相关数据和签约数据的网元为归属签约服务器(home subscriber server，HSS)；负责策略、计费功能的网元称为策略与计费控制规则功能(policy and charging rule function，PCRF)网元。
又例如，在5G移动通信系统中，按照具体的逻辑功能划分，核心网可以分为控制面(control plane，CP)和用户面(user plane，UP)。其中，CN中负责控制面功能的网元可以统称为控制面网元，负责用户面功能的网元可以统称为用户面网元。具体的，在用户面，作为数据网络的接口、负责用户面数据转发等功能的网元为用户面功能(user plane function，UPF)网元。在控制面中，负责接入控制、移动性管理功能的网元称为接入和移动性管理功能(access and mobility management function，AMF)网元；负责会话管理、控制策略的执行的网元称为会话管理功能(session management function，SMF)网元；负责管理签约数据、用户接入授权等功能的网元称为统一数据管理(unified data management，UDM)网元；负责计费、策略控制功能的网元称为策略控制功能(Policy and charging function，PCF)网元；负责传输应用侧对网络侧的需求的应用功能(application function，AF)网元。
5)、NTN通信：
NTN通信可利用无人机、高空平台(high altitude platform station，HAPS)、卫星等设备进行组网，为终端设备提供数据传输、语音通信等服务。其中，高空平台距地面高度可为8～50千米(km)。按照卫星高度，即卫星轨位高度，NTN通信中的卫星通信系统可包括地球静止轨道(geostationary earth orbit，GEO)卫星、中地球轨道(medium earth orbit，MEO)卫星和低地球轨道(low-earth orbit，LEO)卫星。下面分别对其进行描述。
1、GEO卫星：又称为地球同步卫星或静止卫星。GEO卫星的运动速度与地球的自转速度相同，因此，GEO卫星相对地面保持静止状态。对应的，GEO卫星的小区也是静止的。GEO卫星的轨道较高，例如，GEO卫星的轨道高度可为35786km，从而可提供较大的覆盖面积。GEO卫星的小区直径通常可为500km。
2、MEO卫星，为一种非静止轨道(non-geostationary earth orbit，NGEO)卫星。非静止轨道卫星的运动速度与地球的自转速度不同，因此，非静止轨道卫星相对地面是运动的。MEO卫星的轨道高度在2000～35786km范围内，可通过相对较少的卫星数目实现全球覆盖。MEO卫星主要用于定位与导航。
3、LEO卫星：为另一种NGEO卫星。LEO卫星的轨道高度在300～2000km范围内，具有数据传播时延小、传输损耗小、发射成本低的优点。LEO卫星相对地面移动较快，大约7km/s，因此，LEO卫星提供服务的覆盖区域也随之移动。
在NTN通信中，NTN设备(例如，高空平台或者卫星等)的工作模式可包括：透传模式(transparent)和非透传模式。
透传也称为弯管转发传输。NTN设备工作在透传模式时具有中继转发功能，NTN设备可对信号进行频率转换和/或放大处理，但不会改变信号的内容。示例性的，透传模式的 应用场景可以如图2A所示。在图2A所示的应用场景中，网络设备设置在地面，可通过CN连接至数据网络(data network，DN)；卫星和网关设备可作为网络设备的射频拉远单元(remote radio unit，RRU)，用于在网络设备和终端设备之间传递信息。
非透传模式也可称为再生(regenerative)模式。工作在非透传模式的NTN设备具有网络设备的全部或部分能力。示例性的，非透传模式的应用场景可以如图2B所示。在图2B所示应用场景中，卫星可作为网络设备与网关设备组成接入网，并通过网关设备与核心网进行通信。例如，卫星可作为网络设备，通过网关设备与核心网中的AMF建立N2接口或者Ng接口连接。另外，卫星还可为终端设备提供无线接入服务。
6)、SSB，可以包括主同步信号(primary synchronisation signal，PSS)、辅同步信号(secondary synchronisation signal，SSS)和物理广播信道(physical broadcast channel，PBCH)。其中，PSS可以用于传输小区号，SSS可以用于传输小区组号，小区号和小区组号共同决定了移动通信系统中的多个物理小区号(physical cell identity，PCI)。一旦终端设备成功搜索到了PSS和SSS，也就知道了承载PSS和SSS的载波的物理小区号，从而具备了解析SSB中包含的系统消息的能力。
SSB中的系统信息可以是由PBCH携带的，由于这些信息是终端设备接入网络所必须的信息，因此可以称为主消息块(main information block，MIB)。MIB中可以包含系统帧号和初始接入的子载波间隔等。
MIB中包含的信息有限，还不足以支持终端设备接入小区。因此，终端设备还可获取其他系统信息，例如系统信息块(system information block，SIB)1。SIB1可以160毫秒(ms)为周期在物理下行共享信道(physical downlink shared channel，PDSCH)上传输，终端设备可在PBCH所携带的MIB中获取SIB1传输所使用的参数，从而可以接收SIB1。如此，终端设备可获取到接入小区所需的系统信息，后续可以接入小区。
7)、无线资源控制(radio resource control，RRC)连接状态。在移动通信系统中，终端设备的RRC连接状态包括：RRC连接态(RRC_connected，简称连接态)、RRC空闲态(RRC_idle，简称空闲态)。
终端设备处于空闲态时，终端设备与网络设备的RRC连接断开，网络设备与终端设备不再保存终端设备上下文信息，终端设备可以接收网络设备发送的广播信息(例如系统信息)和寻呼消息。
终端设备处于连接态时，终端设备与网络设备之间存在RRC连接，且二者能够通过所述RRC连接进行通信。在RRC连接态，如果出现小区切换失败、无线链路失败、RRC连接重配(RRC connection reconfiguration)流程失败等情况，终端设备会触发RRC连接重建流程。
8)、本申请中，用于体现信号质量的参数可以包括但不限于以下至少一项：参考信号接收功率(reference signal receiving power，RSRP)、参考信号接收质量(reference signal receiving quality，RSRQ)、或接收的信号强度指示(received signal strength indication，RSSI)。
9)、波位，可为波束覆盖的区域。例如，如图1所示，T1时刻，波束0覆盖的区域为一个波位。
本申请实施例中，用于实现卫星的功能的装置可以是卫星；也可以是能够支持外形实现该功能的装置，例如芯片系统，该装置可以被安装在卫星中。以下描述本申请实施例提供的技术方案时，以用于实现卫星的功能的装置是卫星为例，来描述本申请实施例提供的 技术方案。
本申请实施例中，用于实现终端设备的功能的装置可以是终端设备；也可以是能够支持终端设备实现该功能的装置，例如芯片系统，该装置可以被安装在终端设备中。本申请实施例中，芯片系统可以由芯片构成，也可以包括芯片和其他分立器件。本申请实施例提供的技术方案中，以用于实现终端设备的功能的装置是终端设备为例，来描述本申请实施例提供的技术方案。
本申请实施例中，对于名词的数目，除非特别说明，表示“单数名词或复数名词”，即“一个或多个”。“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。“以下至少一项(个)”或其类似表达，是指这些项(个)中的任意组合，包括单项(个)或复数项(个)的任意组合。
另外，需要理解的是，在本申请的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不应理解为指示或暗示相对重要性，也不应理解为指示或暗示顺序。
下面将结合附图，对本申请实施例进行详细描述。
图3示出了本申请实施例提供的方法适用的一种移动通信系统的结构。参阅图3所示，在该系统中包括：网络设备和终端设备(例如图3中所示的终端设备a、终端设备b)。
所述网络设备，是网络侧能够接收和发射无线信号的实体，负责为处于其覆盖范围内的终端设备提供无线接入有关的服务，实现物理层功能、资源调度和无线资源管理、服务质量(Quality of Service，QoS)管理、无线接入控制以及移动性管理功能。
所述终端设备，为用户侧能够接收和发射无线信号的实体，需要通过所述网络设备接入网络。所述终端设备可以为各种为用户提供语音和/或数据连通性的设备，例如图3所示，所述终端设备可以为车载设备、智能手机等。
图4示出了本申请实施例提供的方法适用的另一种移动通信系统的结构。该通信系统可为NTN通信系统。本申请实施例中，以NTN通信系统为卫星通信系统为例进行说明。如图4所示，NTN通信系统中包括卫星(例如，图4中的卫星401、卫星402和卫星403)、CN设备和终端设备。
CN设备和终端设备可以分别参照上述对CN设备和终端设备的描述。
卫星可为NGEO卫星，例如，LEO卫星。卫星可通过广播通信信号和导航信号等与终端设备进行无线通信。可选的，每颗卫星可以通过多个波束为终端设备提供通信服务、导航服务和定位服务等。例如，每颗卫星采用多个波束覆盖服务区域，不同波束之间的关系可为时分、频分和空分中的一种或多种。至少一个卫星可与地面站设备进行通信。例如，卫星403可连接至CN设备，与CN设备进行无线通信。
卫星可工作在透传模式下，例如，图4中的卫星403工作在透传模式下。卫星也可工作在非透传模式下，例如，图4中的卫星401和卫星402工作在非透传模式下。此外，卫星还可以工作在准地球固定(quasi earth-fixed)模式或卫星固定(satellite-fixed)模式。其中，quasi earth-fixed模式也可称为凝视模式，是指通过动态调整卫星的波束指向，使其在一段时间内持续服务某一物理区域。satellite-fixed模式是指卫星的波束随卫星一起移动，其服务的物理区域也持续变化。
本申请实施例中提及的卫星，可以为卫星基站，也可包括用于对信息进行中继的轨道接收机或中继器，或者为搭载在卫星上的网络设备。
还需要指出的是，如图3或图4所示的移动通信系统作为一个示例，并不对本申请实施例提供的方法适用的通信系统构成限定。总之，本申请实施例提供的方法，适用于各种终端设备支持多发能力的通信系统和应用场景中，即本申请实施例还可以应用于各种类型和制式的通信系统，例如：5G通信系统、LTE通信系统、无线保真(wireless fidelity，Wi-Fi)系统、车到万物(vehicle to everything，V2X)、长期演进-车联网(LTE-vehicle，LTE-V)、车到车(vehicle to vehicle，V2V)、车联网、机器类通信(machine type communications，MTC)、物联网(internet of things，IoT)、长期演进-机器到机器(LTE-machine to machine，LTE-M)、机器到机器(machine to machine，M2M)、通信导航一体化(integrated communication and navigation,IcaN)系统、全球导航卫星系统(global navigation satellite system，GNSS)或超密低轨卫星通信系统等，本申请实施例不予限定。
为了便于理解本申请，下面对相关技术进行说明。
1、CD-SSB和NCD-SSB：
CD-SSB包含：关联的控制资源集(control resource set)的配置信息(即CORESET 0的配置信息)，以及类型0物理下行控制信道公共搜索空间(Type0physical downlink control channal common search space，Type 0-PDCCH CSS)的监听时机的配置信息。目前，CD-SSB可用于初始接入、小区重选或小区切换。处于空闲态的终端设备可根据CD-SSB进行初始接入或小区重选。处于连接态的终端设备可根据CD-SSB进行小区切换。
NCD-SSB不包含：关联的控制资源集的配置信息(即CORESET 0的配置信息)，或Type 0-PDCCH CSS的监听时机的配置信息。NCD-SSB可用于无线资源管理。
目前，CD-SSB和NCD-SSB是频分复用的，即CD-SSB和NCD-SSB承载在不同的频率上。可选的，CD-SSB和NCD-SSB承载在不同的带宽部分(bandwidth part，BWP)上。例如，如图5所示，CD-SSB包括SSB1和SSB3，NCD-SSB包括SSB2和SSB4。若UE1的工作频率包括初始BWP(initial BWP)，例如，UE1的工作频率为专用BWP1(dedicated BWP1)，专用BWP1包括初始BWP，则UE1可根据初始BWP中的SSB3进行初始接入、小区切换或小区重选。NCD-SSB位于初始BWP之外，工作频率在初始BWP之外的终端设备可根据NCD-SSB进行信号测量。例如，UE2的工作频率为专用BWP2，专用BWP2不包括初始BWP，则UE2可根据SSB4进行信号测量。
此外，CD-SSB的传输频率和NCD-SSB的传输频率之间可存在一定的偏移(下面称为频率偏移)。终端设备可在检测到NCD-SSB后，根据该频率偏移确定CD-SSB在频域上的位置。其中，该频率偏移可通过携带在NCD-SSB中的参数K_SSB指示，且与主信息块(main information block，MIB)消息中的SSB子载波偏移(ssb-SubcarrierOffset)参数对应。
2、小区切换：
终端设备处于连接态时，网络设备可通过RRC连接重配置消息向终端设备发送测量配置信息。终端设备根据网络设备下发的测量配置信息，测量服务小区和邻区的信号强度，并上报测量结果。然后，网络设备可根据测量结果判决是否进行切换。下面结合图6说明目前的切换流程。
S601：源网络设备向终端设备发送第一RRC重配置(RRCReconfiguration)消息。
其中，第一RRC重配置消息可包含至少一个小区的测量配置信息。该至少一个小区可包括终端设备的服务小区和邻区。
S602：终端设备向源网络设备发送第一RRC重配置完成(RRCReconfigurationComplete) 消息。
其中，第一RRC重配置完成消息可用于指示终端设备已接收到第一RRC重配置消息。
S603：终端设备根据测量配置信息进行测量，并向源网络设备发送测量报告。
可选的，终端设备可根据测量配置信息，使用当前激活BWP关联的SSB进行服务小区和/或邻区的测量。在一些可能的方式中，终端设备可周期性的向源网络设备发送测量报告。其中，发送测量报告的周期可为预先设定的，也可以终端设备从源网络设备获取的。在另一些可能的方式中，终端设备可在测量结果满足上报条件时，向源网络设备发送测量报告。其中，该上报条件可包括以下至少一项：服务小区的信号质量小于或等于第一信号质量阈值，邻区的信号质量大于或等于第二信号质量阈值。
S604：源网络设备根据来自终端设备的测量报告执行切换判决。
例如，若终端设备的测量报告包括目标网络设备的小区的信号质量，且目标网络设备的小区的信号质量大于或等于第二信号质量阈值，则源网络设备可确定将终端设备切换到目标网络设备。
S605：源网络设备向目标网络设备发送切换请求(handover request)消息。
其中，该切换请求用于请求将终端设备从源网络设备切换到目标网络设备。
S606：目标网络设备执行准入控制。
例如，目标网络设备可为终端设备配置切换所需的资源。
S607：目标网络设备向源网络设备发送切换请求响应(handover request acknowledgement)消息。
其中，该切换请求响应消息可用于指示目标网络设备同意将终端设备切换到目标网络设备。
S608：源网络设备向终端设备发送第二RRC重配置消息。
其中，第二RRC重配置消息也可称为切换命令，用于指示终端设备从源网络设备切换到目标网络设备。
可选的，第二RRC重配置消息可以包含目标网络设备的小区的配置参数，例如，目标网络设备的小区的标识，或者目标网络设备的小区的频点。
S609：源网络设备向目标网络设备发送序号(sequence number，SN)状态转移(SN status transfer)消息。
其中，SN状态转移消息可包含用于指示源网络设备已传输给终端设备的数据包的序号。
可选的，源网络设备将要发送给终端设备的数据转发至目标网络设备。
S610：终端设备根据第二RRC重配置消息中的目标网络设备的小区的配置参数，向目标网络设备发送随机接入(random access)消息，以请求接入目标网络设备的小区。
其中，随机接入消息中的随机接入前导为专用前导，与初始接入时使用的基于竞争的随机接入前导不同。此外，用于发送该随机接入的资源的周期可为以下至少之一：10ms、20ms、40ms、80ms或160ms。
S611：目标网络设备向终端设备发送随机接入响应(random access response，RAR)消息。
S612：终端设备向目标网络设备发送第二RRC重配置完成消息。
在接入到目标网络设备后，终端设备可与目标网络设备进行数据交互。例如，终端设 备可向目标网络设备发送上行数据。又例如，终端设备可接收来自目标网络设备的下行数据。
S613：目标网络设备向AMF发送路径切换请求(path switch request)消息。
其中，路径切换请求消息可用于请求核心网将终端设备的数据发送给目标网络设备。
S614：AMF向目标网络设备发送路径切换请求响应(path switch request acknowledgement)消息。
在接收到路径切换请求响应消息后，目标网络设备可向核心网发送来自终端设备的上行数据。
通过图6所示方法，终端设备可从源网络设备切换至目标网络设备。
3、小区重选：
终端设备处于空闲态时，在驻留到服务小区之后，终端设备可通过测量服务小区和邻区的信号强度来持续的进行小区重选，以便驻留到优先级更高或信道质量更好的小区。小区重选流程可包括步骤H1-H3：
H1：第一网络设备的小区广播至少一个小区的测量配置信息。该至少一个小区可包括终端设备的服务小区和邻区。
H2：终端设备根据测量配置信息，测量至少一个小区的信号质量。
可选的，终端设备可根据测量配置信息，使用当前激活BWP关联的SSB进行服务小区和/或邻区的测量，从而获得服务小区和/或邻区的信号质量。
H3：当满足重选条件时，终端设备可重选至第二网络设备的小区。
其中，重选条件可包括以下至少一项：第二网络设备的小区的信号质量大于第一网络设备的小区的信号质量，第二网络设备的小区的信号质量大于或等于第三信号质量阈值。第三信号质量阈值可以是预先设定的，也可以是终端设备从第一网络设备获取的。
目前，SSB既用于初始接入，又用于小区切换或小区重选。因此，小区需要频繁发送SSB，以便终端设备能够根据该SSB进行初始接入、小区切换或小区重选。这样，发送SSB的开销较大，通信效率也较低。如何降低SSB的开销，提高测量SSB的效率，是本申请需要解决的一个问题。
并且，目前的小区切换或小区重选方法通常是基于终端设备的移动进行设计的，根据终端设备检测的信号质量进行小区切换或小区重选。然而，NTN通信系统中的远近效应并不明显，此时，依靠信号质量触发小区切换或小区重选，效率较低。而当卫星采用跳波束的方式进行区域覆盖时，一个或多个波束覆盖的区域内的终端设备可能均需要进行频繁的小区切换或小区重选。如何提高小区切换或小区重选的效率，是本申请需要解决的另一个问题。
下面结合附图对本申请提供的方案进行说明。
本申请实施例提供了一种通信方法，该方法可应用于图3或图4所示的通信系统中。下面参阅图7A所示的流程图，对该方法的流程进行具体说明。
S701：第一小区发送第一SSB。
其中，第一SSB为用于初始接入的SSB。例如，第一SSB可用于初始随机接入流程。另外，第一SSB还可用于小区切换或小区重选之外的流程，例如，波束失败恢复、上行数据传输或RRC连接重新建立等流程。
其中，第一小区可为第一卫星覆盖区域内的一个小区，第一卫星可覆盖至少一个区域。
可选的，第一小区可根据第一SSB的配置信息(下面称为第一配置信息)发送第一SSB。其中，第一配置信息可包括以下至少一项：
1、第一SSB的时域长度：可表示第一SSB占用的时域资源的时间长度。示例性的，第一SSB的时域长度为4个正交频分复用(orthogonal frequency division multiplexing，OFDM)符号(symbol)。
2、第一SSB的发送周期：可表示发送第一SSB的周期。示例性的，第一SSB的发送周期可为5ms、10ms、20ms、40ms、80ms或160ms。
3、第一SSB的SSB位图(bitmap，也称为比特位指示)：可用于指示一个或者多个SSB是否存在。示例性地，假设最多存在4个SSB(例如，这4个SSB可标识为SSB0、SSB1、SSB2和SSB3)，SSB位图中的4个比特与4个SSB一一对应，每个比特用于表示对应的SSB是否存在。当SSB位图中的1个比特的值为0时，表示对应的SSB在某一时间段不存在；当SSB位图中的1个比特的值为1时，表示对应的SSB在某一时间段存在。例如，SSB位图为0011时，表示SSB0和SSB1在当前时间段不存在，SSB2和SSB3在当前时间段存在；SSB位图为1011时，表示SSB0、SSB2和SSB3在当前时间段存在，SSB1在当前时间段不存在。
4、第一SSB的测量窗口配置：可用于指示能够测量到第一SSB的多个时间窗。该测量窗口配置可包括用于指示该多个时间窗中一个时间窗的信息，以及该多个时间窗中每两个相邻时间窗之间的时间间隔。其中，每两个相邻时间窗之间的时间间隔可与第一SSB的发送周期相同。例如，该测量窗口配置可包括：能够测量到第一SSB的时间窗1的起始时间信息(例如，0ms)和结束时间信息(例如，5ms)，以及每两个相邻时间窗之间的时间间隔(例如，20ms)。又例如，该测量窗口配置可包括：能够测量到第一SSB的时间窗1的起始时间信息(例如，0ms)，时间窗1占用的时间长度(例如，5ms)，以及每两个相邻时间窗之间的时间间隔(例如，20ms)。
5、第一SSB的测量窗口偏移(offset)：表示第一SSB的测量窗口的开始时间相对于时间参考点的偏移，该时间参考点可以为帧边界或者系统定义的时间点。例如，第一SSB的测量窗口偏移为4ms，表示第一SSB的测量窗口的开始时间为在帧边界或者系统定义的时间点上延迟4ms。
6、第一SSB的参考点位置(reference location)：表示第一SSB所在波束的中心点在球面上的投影位置(例如，经纬度位置或者地心地固(earth-centered earth-fixed，ECEF)坐标系下的xyz坐标)。
其中，第一配置信息可为预先设置的，也可以为第一小区确定的，还可为其他设备(例如，地面的网络设备)为第一小区设置的。
另外，第一配置信息可通过与SIB1的更新机制相同的方式进行更新。当第一配置信息更新时，可触发第一小区的SIB1的更新。
可选的，第一小区可通过显示或隐式的方式指示第一SSB为用于初始接入的SSB。例如，第一SSB包含第一指示，第一指示用于指示当前的SSB为用于初始接入的SSB。其中，第一指示可位于第一SSB的第一字段中，当第一字段的值为第一值时，当前的SSB为用于初始接入的SSB。这样，终端设备可根据第一指示确定接收到的SSB为第一SSB。又例如，第一SSB包含第一默认参数。这样，终端设备可根该第一默认参数确定接收到的SSB为第一SSB。又例如，第一SSB承载在第一设定频率上。这样，终端设备可根据承载 第一SSB的第一设定频率确定接收到的SSB为第一SSB。
S702：第一小区发送第二SSB。相应的，终端设备接收来自第一小区的第二SSB。
其中，第二SSB为专门用于小区切换或小区重选的SSB。这样，接收到第二SSB的终端设备可根据第二SSB切换或重选到第一小区。
可选的，第一小区可根据第二SSB的配置信息(下面称为第二配置信息)发送第二SSB。其中，第二配置信息可包括以下至少一项：第二SSB的时域长度、第二SSB的发送周期、第二SSB的SSB比特图、第二SSB的测量窗口配置、第二SSB的测量窗口偏移、第二SSB的参考点位置。第二配置信息的具体内容可参考对第一配置信息的说明，只是将其中的第一SSB替换为第二SSB，重复之处不再赘述。
第二配置信息可为预先设置的，也可以为第一小区确定的，还可为其他设备(例如，地面的网络设备)为第一小区设置的。
可选的，第一小区可通过显示或隐式的方式指示第二SSB。例如，第二SSB包含第二指示，第二指示用于指示当前的SSB为用于小区切换或小区重选的SSB。其中，第二指示可位于第二SSB的第二字段中，当第二字段的值为第二值时，当前的SSB为用于小区切换或小区重选的SSB。这样，终端设备可根据第二指示确定接收到的SSB为第二SSB。又例如，第二SSB包含第二默认参数。这样，终端设备可根据第二默认参数确定接收到的SSB为第二SSB。又例如，第二SSB承载在第二设定频率上。这样，终端设备可根据承载第二SSB的第二设定频率，确定接收到的SSB为第二SSB。
可选的，在图7A所示方法中，第一SSB不用于小区切换或小区重选，这样，接收到第一SSB的终端设备不会根据第一SSB切换或重选到第一小区。第二SSB不用于初始接入，这样，接收到第二SSB的终端设备不会根据第二SSB初始接入到第一小区。
可选的，在图7A所示方法中，第一SSB和第二SSB可通过以下实现方式之一实现：
实现方式1：第一SSB和第二SSB均为NR SSB。也就是说，第一SSB和第二SSB可复用NR SSB的图样(pattern)。该方式可复用NR SSB的图样，提高了方案的可用性，易于实现。
实现方式2：第一SSB为CD-SSB，第二SSB为NCD-SSB。此时，第一SSB可复用NR SSB的图样，占用NR SSB的时间窗，并使用NR SSB的序号。第二SSB可不占用NR SSB的时间窗，不使用NR SBB的序号。示例性的，NR SSB的时间窗长度为5ms，NR SSB的序号最大为64个。该方式中，第二SSB不使用NR SSB的时间窗和序号，从而可扩展出更多可用的SSB，提高小区重选和小区切换的效率。
可选的，在实现方式2中，第二配置信息还可包括待测NCD-SSB集合。示例性的，待测NCD-SSB集合可包括待测NCD-SSB的序号信息。例如，待测NCD-SSB集合包括{NCD-SSB0,NCD-SSB1,…,NCD-SSBM}中的一个或多个。其中，M为网络支持的最大NCD-SSB数，如M可为4、8、16、32或64。
另外，在实现方式2中，当一个时间窗内包含多个CD-SSB和/或NCD-SSB时，CD-SSB和NCD-SSB可通过以下至少一项进行区分：
1、SSB的图样：CD-SSB的图样和NCD-SSB的图样不同，因此，终端设备可根据图样确定接收到的SSB是CD-SSB还是NCD-SSB。
2、SSB的发送周期：CD-SSB的发送周期和NCD-SSB的发送周期可以是不同的。例如，CD-SSB的周期为20ms，NCD-SSB的周期为5s。因此，终端设备可根据SSB的发送 周期确定接收到的SSB是CD-SSB还是NCD-SSB。
3、MIB：在一些可能的方式中，MIB中可包含用于指示SSB种类的第一类型指示信息，该第一类型指示信息可占用1bit。例如，当该第一类型指示信息的取值为0时，代表当前的SSB为CD-SSB；当该第一类型指示信息的取值为1时，代表当前的SSB为NCD-SSB。在另一些可能的方式中，MIB也可以通过隐式方式指示SSB种类。例如，当MIB的加扰方式为第一加扰方式时，代表当前的SSB为CD-SSB；当MIB的加扰方式为第二加扰方式时，代表当前的SSB为NCD-SSB。其中，第一加扰方式和第二加扰方式不同。又例如，当MIB所对应的解调参考信号(demodulation reference signal，DMRS)pattern为第一图样时，代表当前的SSB为CD-SSB；当MIB所对应的DMRS pattern为第二图样时，代表当前的SSB为NCD-SSB。其中，第一图样和第二图样不同。
4、PBCH载荷(payload)：在一些可能的方式中，PBCH载荷中可包含用于指示SSB种类的第二类型指示信息，该第二类型指示信息可占用1bit。例如，当该第二类型指示信息的取值为0时，代表当前的SSB为CD-SSB；当该第二类型指示信息的取值为1时，代表当前的SSB为NCD-SSB。在另一些可能的方式中，PBCH载荷也可以通过隐式方式指示SSB种类。例如，当PBCH载荷的加扰方式为第三加扰方式时，代表当前的SSB为CD-SSB；当PBCH载荷的加扰方式为第四加扰方式时，代表当前的SSB为NCD-SSB。其中，第三加扰方式和第四加扰方式不同。
通过图7A所示的方法，第一小区可分别发送用于初始接入的第一SSB和用于小区切换或小区重选的第二SSB。这样，当需要终端设备接入第一小区时，第一小区可发送第一SSB；当需要终端设备切换或重选到第一小区时，第一小区可发送第二SSB，从而可按需发送SSB，降低发送SSB的开销，提高终端设备测量SSB的效率。
并且，第一小区分别发送用于初始接入的第一SSB和用于小区切换或小区重选的第二SSB。这样，终端设备在接收到第二SSB后，才根据第二SSB进行小区切换或小区重选，从而可避免在NTN通信中仅依靠信号质量触发小区切换或小区重选导致的效率低的问题，进而可提高小区重选和小区切换的效率。
可选的，在S701中，第一小区可在第一区域内发送第一SSB。例如，如图7B所示，S701包括S701a：第一小区向第一区域内的终端设备发送第一SSB。在S702中，第一小区可在第二区域内发送第二SSB。例如，如图7B所示，S702包括S702a：第一小区向第二区域内的终端设备发送第二SSB。
其中，第一区域可为第一小区发送数据信号的区域，第二区域可包含在第二小区发送数据信号的区域中。第二小区可为第二卫星覆盖区域内的一个小区，第一卫星和第二卫星为相邻的卫星，第二卫星可覆盖至少一个区域。例如，如图8所示，第一卫星的第一小区可在波位1-波位4中发送数据信号；第二卫星的第二小区可在波位5-波位8中发送数据信号。第一卫星和第二卫星均向右移动。此时，第一小区在波位1-波位4中发送第一SSB。第一小区在波位5中发送第二SSB。
通过该方法，第一小区可在第一区域内发送用于初始接入的第一SSB；在第二区域内发送用于小区切换或小区重选的第二SSB。这样，在跳波束系统中，位于第二区域内的终端设备可在第一小区使用用于发送数据信号的波束覆盖第二区域之前，根据第二SSB进行广播信号质量的测量和下行同步，从而可在第一小区使用用于发送数据信号的波束覆盖第二区域时，无缝重选或切换至第一小区，提高小区重选和小区切换的效率。
可选的，在图7A所示方法中，第一SSB的发送时间和第二SSB的发送时间不重叠，换句话说，第一SSB和第二SSB的发送时间是时分的。例如，如图9所示，当第一SSB和第二SSB均为NR SSB时，第一SSB和第二SSB均位于NR SSB突发(burst)中，第一SSB的发送时间和第二SSB的发送时间不重叠。又例如，如图10所示，当第一SSB为CD-SSB，第二SSB为NCD-SSB时，第一SSB位于NR SSB突发中，第二SSB位于NR SSB突发外。
通过该方法，第一SSB和第二SSB在时域上不重叠，从而可降低第一SSB和第二SSB之间的干扰。
可选的，在图7A所示方法中，第一SSB的发送周期小于第二SSB的发送周期。示例性的，第一SSB的发送周期为以下之一：5ms、10ms、20ms、40ms、80ms、160ms；第二SSB的发送周期为几～几百秒。例如，如图9所示，当第一SSB和第二SSB均为NR SSB时，每个NR SSB突发中均包含第一SSB，部分NR SSB突发中包含第二SSB，这样，第二SSB的发送周期大于第一SSB的发送周期。又例如，如图10所示，当第一SSB为CD-SSB，第二SSB为NCD-SSB时，第二SSB的发送周期为周期2，第一SSB的发送周期为周期1，周期2大于周期1。
通过该方法，第一SSB的发送周期小于第二SSB的发送周期，从而可降低发送第二SSB的开销。
可选的，在图7A所示方法中，第一SSB关联的第一随机接入时机(随机接入信道(random access channel，RACH)occasion，RO)与第二SSB关联的第二RO不同。其中，第一RO为第一SSB关联的接入时机，终端设备可在第一RO进行与初始随机接入、波束恢复或数据传输请求等相关的接入。第二RO为第二SSB关联的接入时机，群切换后的终端设备可在第二RO进行接入。RO可表示发送随机接入导码所占的资源(如时域位置和/或时间长度)。
其中，第一RO和第二RO的如下至少一项参数不同：
1、时域周期：可表示RO的资源在时域上的周期。可选的，如图11所示，在时域上，第一RO可位于关联的第一SSB之后，第一RO的时域周期可与第一SSB的发送周期相同；在时域上，第二RO可位于关联的第二SSB之后，第二RO的时域周期可与第二SSB的发送周期相同。例如，第一SSB的发送周期为周期1，第一RO的时域周期也为周期1；和/或，第二SSB的发送周期为周期2，第二RO的时域周期也为周期2。
2、持续时间：可表示RO的时域资源对应的时间长度。例如，第一RO的时域资源对应的时间长度为3ms，即第一RO的持续时间为3ms；第二RO的时域资源对应的时间长度为10ms，即第二RO的持续时间为10ms。
3、频域位置：可表示RO的资源在频域上的位置。第一RO的频域位置和第二RO的频域位置可部分重叠，也可以不重叠。
4、极化方式：可表示RO对应的极化方式，例如左旋圆极化、右旋圆极化、椭圆极化或线极化等。示例性的，第一RO对应的极化方式为左旋圆极化，第二RO对应的极化方式为右旋圆极化。
可选的，当第一小区通过图7A所示方法发送第一SSB和第二SSB时，终端设备可通过下文中的过程1进行切换或者通过下文中的过程2进行重选。下面分别对此进行说明。
过程1：
下面参考图12，对过程1中的方法进行说明。该方法包括：
S1201：第二小区向终端设备发送第三SSB。相应的，终端设备接收来自第二小区的第三SSB。
其中，第三SSB为用于初始接入的SSB。例如，第三SSB可用于初始随机接入流程。另外，第三SSB还可用于小区切换或小区重选之外的流程，例如，波束失败恢复、上行数据传输或RRC连接重新建立等流程。
其中，第二小区可为第二卫星的一个小区，具体内容可参考图7A中对第二小区的说明，此处不再赘述。
可选的，第二小区可根据第三SSB的配置信息(下面称为第三配置信息)发送第三SSB。其中，第三配置信息可包括以下至少一项：第三SSB的时域长度、第三SSB的周期、第三SSB的SSB比特图、第三SSB的测量窗口配置、第三SSB的测量窗口偏移、第三SSB的参考点位置。第三配置信息的具体内容可参考对第一配置信息的说明，只是将其中的第一SSB替换为第三SSB，重复之处不再赘述。
第三配置信息可为预先设置的，也可以为第二小区确定的，还可为其他设备(例如，地面的网络设备)为第二小区设置的。
可选的，第二小区可通过显示或隐式的方式指示第三SSB为用于初始接入的SSB。指示的方式可参考S701中对“指示第一SSB为用于初始接入的SSB”的说明，只是将第一SSB替换为第三SSB，此处不再赘述。
另外，第三SSB不用于小区切换或小区重选。这样，接收到第三SSB的终端设备不会根据第三SSB切换或重选到第二小区。
S1202：终端设备根据第三SSB，接入到第二小区。
可选的，终端设备可为第二区域内的终端设备。示例性的，第二区域可包含在第二小区发送数据信号的区域中。第二区域的具体内容可参考图7A所示方法中对第二区域的说明，此处不再赘述。
本申请对终端设备根据第三SSB接入第二小区的具体过程不作限定。在接入第二小区后，终端设备处于连接态。
S1203：第一小区发送第二SSB。相应的，终端设备接收来自第一小区的第二SSB。
S1203的具体内容可参考图7A所示方法中对S702的说明，此处不再赘述。
S1204：终端设备根据第二SSB，向第二小区发送测量报告。
可选的，终端设备可根据第二SSB确定接收到的第一小区的信号质量，当接收到的第一小区的信号质量满足设定上报条件时，终端设备可向第二小区发送测量报告。其中，设定上报条件可包括：第一小区的信号质量大于设定信号质量阈值。测量报告可包括：第二SSB的序号和终端设备接收到的第一小区的信号强度。
在接收到测量报告后，第二小区可确定将终端设备切换到第一小区，并通过S605-S608所示的方法，将终端设备从第二小区切换到第一小区。
通过该方法，处于连接态的终端设备可根据第二SSB切换到第一小区。当第二区域内的连接态终端设备均通过该方法切换到第一小区时，可提高群切换的效率。
可选的，图12所示方法还包括步骤A1：
A1：终端设备获取第二配置信息。
其中，第二配置信息用于指示第一小区发送第二SSB的配置。第二配置信息的具体内 容可参考S702，此处不再赘述。
可选的，当第二SSB为NCD-SSB时，第二配置信息可包括：第二SSB的测量窗口配置、第二SSB的测量窗口偏移、第二SSB的参考点位置以及待测NCD-SSB集合。
可选的，终端设备可通过以下方式之一获取第二配置信息：
方式一：终端设备接收第一小区广播的第二配置信息。
其中，第一小区可通过广播消息发送第二配置信息，这样，终端设备通过来自第一小区的广播消息获取第二配置信息。
可选的，在方式一中，步骤A1和S1201-S1202之间的执行顺序不限。
方式二：终端设备可接收第二小区转发的来自第一小区的第二配置信息。
其中，方式二可包括步骤B1-B2：
B1：第一小区向第二小区发送第二配置信息。
可选的，第一小区可在以下情况至少之一时，向第二小区发送该配置信息：
情况1：第一小区初始确定第一小区发送第二SSB的配置。此时，第一小区向第二小区发送的第二配置信息用于指示初始确定的第一小区发送第二SSB的配置。
情况2：第一小区更新第一小区发送第二SSB的配置。此时，第一小区向第二小区发送的第二配置信息用于指示第一小区发送第二SSB的更新的配置。
可选的，在情况2中，第一小区不更新本小区的SIB1。
B2：第二小区向终端设备发送第二配置信息。相应的，终端设备接收来自第二小区的第二配置信息。
其中，该第二配置信息可承载在现有消息中，也可以承载在新的消息中，本申请对此不作限定。
可选的，在方式二中，步骤A1可在S1202之后执行。
在步骤A1之后，S1203可包括：终端设备根据第二配置信息，接收来自第一小区的第二SSB。例如，当第二配置信息包括第二SSB的测量窗口配置时，终端设备可在测量窗口配置指示的时间窗内接收来自第一小区的第二SSB。又例如，当第二配置信息包括第二SSB的周期时，终端设备以第二SSB的周期为周期，检测来自第一小区的第二SSB。又例如，第二SSB为NCD-SSB。再例如，终端设备可根据自身的全球导航卫星系统(global navigation satellite system，GNSS)位置和参考点位置，选择合适的初始NCD-SSB，并接收该初始NCD-SSB。示例性地，终端设备可基于终端设备位置和参考点位置距离最近准则或终端设备位置、卫星位置和参考点位置三者的夹角最小准则选择初始NCD-SSB。
通过该方法，终端设备可根据第二配置信息接收来自第一小区的第二SSB，从而可避免终端设备盲检测第二SSB，进而可降低终端设备的能耗。
可选的，在S1204之后，图12所示方法还包括步骤C1-C2：
C1：第二小区向终端设备发送切换命令。相应的，终端设备接收来自第二小区的切换命令。
其中，切换命令可用于指示终端设备切换到第一小区。切换命令可为S608中的第二RRC重配置消息，具体内容可参考S608，此处不再赘述。
C2：终端设备接收来自第一小区的第一SSB。
在一些可能的方式中，终端设备可以盲检测来自第一小区的第一SSB，并根据检测到的第一SSB接入到第一小区。
在另一些可能的方式中，终端设备可根据接收到的第二SSB，接收来自第一小区的第一SSB。可选的，该方式包括步骤D1-D2：
D1：终端设备接收第一偏移指示。
其中，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量。例如，第二SSB的发送时间为T1，与第二SSB相邻的第一SSB的发送时间为T2，则第一偏移指示所指示的时间偏移量ΔT＝T2-T1。
可选的，第一偏移指示可通过在MIB、SIB1、RRC等消息中新增ΔT字段进行指示。或者，第一偏移指示也可通过复用现有协议中的参数K_SSB指示。例如，参数K_SSB中的保留比特中包含第一偏移指示。第一偏移指示所指示的时间偏移量的单位可为符号、时隙、毫秒或帧等。
可选的，终端设备可通过以下方式之一接收第一偏移指示：
方式1：终端设备接收第一小区广播的第一偏移指示。
其中，第一小区可通过广播消息发送第一偏移指示，这样，终端设备通过来自第一小区的广播消息获取第一偏移指示。
可选的，在方式1中，步骤D1和S1201-S1204之间的执行顺序不限。
方式2：终端设备可接收第二小区转发的来自第一小区的第一偏移指示。
可选的，方式2可包括步骤E1-E2：
E1：第一小区向第二小区发送第一偏移指示。相应的，第二小区接收来自第一小区的第一偏移指示。
其中，第一小区可通过第一小区和第二小区之间的接口向第二小区发送第一偏移指示。
E2：第二小区向终端设备发送第一偏移指示。相应的，终端设备接收第一偏移指示。
其中，第一偏移指示可承载在现有的消息中，也可以承载在新的消息中。
D2：终端设备根据第一偏移指示和接收到第二SSB的时间，接收来自第一小区的第一SSB。例如，第一偏移指示所指示的时间偏移量为ΔT，若在S1203中，终端设备在T3时刻接收到第二SSB，则终端设备可在T3+ΔT时刻接收来自第一小区的第一SSB。
下面以第一SSB为CD-SSB，第二SSB为NCD-SSB为例对步骤D1和D2进行说明。第一小区可先后在同一波位上发送NCD-SSB和CD-SSB。在同一波位上，NCD-SSB的发送时间和CD-SSB的发送时间之间有一定的时域偏移。例如，如图13所示，T1时刻，第一小区发送的包含NCD-SSB的波束可覆盖波位5和7，第一卫星发送的包含CD-SSB的波束可覆盖波位1-波位4；T2时刻，第一小区发送的包含NCD-SSB的波束覆盖波位6和8，第一小区发送的包含CD-SSB的波束覆盖波位2、波位4、波位5和波位7。UE1位于波位5内。在T1时刻，UE1可测量来自第一小区的NCD-SSB；在T2时刻，UE1可测量来自第一小区的CD-SSB。由于NCD-SSB的发送时间和CD-SSB的发送时间之间有一定的时域偏移，因此，UE1可根据接收到NCD-SSB的时间，确定预期接收到CD-SSB的时间。
通过该方法，终端设备可根据第一偏移指示和接收到第二SSB的时间，接收来自第一小区的第一SSB，从而无需终端设备盲检测第一SSB，也无需第二小区向终端设备发送第一SSB的配置信息，进而可降低终端设备的能耗，降低获取第一SSB的配置信息的开销。
可选的，当第一SSB可为CD-SSB，第二SSB可为NCD-SSB时，图12所示方法还包括步骤D1：
D1：终端设备使用与NCD-SSB对应的用于切换的资源和/或用于切换的随机接入前导，与第一小区进行通信。
在本申请中，NCD-SSB可与用于切换的资源和/或用于切换的随机接入前导对应。NCD-SSB与用于切换的资源和/或用于切换的随机接入前导之间的对应关系可以是预先设置的，也可以是网络设备(例如，第一卫星或位于地面的网络设备等)确定的。当该对应关系为预先设置的时，终端设备中可保存有该对应关系。当该对应关系是网络设备确定的时，终端设备可从网络设备获取该对应关系。
当NCD-SSB与用于切换的资源对应时，终端设备可通过该资源向第一小区发送随机接入消息。当NCD-SSB与用于切换的随机接入前导对应时，终端设备可向第一小区发送与NCD-SSB对应的随机接入前导。
通过该方法，NCD-SSB可关联专用的切换资源和/或用于切换的随机接入前导，用于群切换时的上行随机接入，从而可提高群切换的效率。并且，通过NCD-SSB关联的切换资源，终端设备无需获取用于群切换的资源配置信息，从而可降低开销。通过NCD-SSB关联的随机接入前导，可避免用于切换的随机接入前导与用于初始接入的随机接入前导之间的冲突进而提高群切换的成功率。
过程2：
下面参考图14，对过程2中的方法进行说明。该方法包括：
S1401：终端设备接收第一偏移指示。
其中，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量。
S1401的具体内容可参考对步骤D1的说明，重复之处不再赘述。
另外，终端设备可为第二区域内处于空闲态的终端设备。示例性的，第二区域可包含在第二小区发送数据信号的区域中。第二区域的具体内容可参考图7A所示方法中对第二区域的说明。
S1402：第一小区发送第二SSB。相应的，终端设备接收来自第一小区的第二SSB。
S1402的具体内容可参考图7A所示方法中对S702的说明，重复之处不再赘述。
S1403：终端设备根据第二SSB，重选到第一小区。
本申请对终端设备根据第二SSB重选到第一小区的过程不作限定。例如，当终端设备根据第二SSB，确定来自第一小区的信号质量大于设定信号质量阈值时，终端设备可重选到第一小区。
另外，本申请对S1401和S1402-S1403的顺序不作限定。
S1404：终端设备根据接收到第二SSB的时间和第一偏移指示，接收来自第一小区的第一SSB。
其中，S1404的具体内容可参考步骤D3，重复之处不再赘述。
可选的，当终端设备处于空闲态时，终端设备可在待检测的同步栅格(synchronization raster)上搜索SSB。若终端设备根据S701中的显示或隐式的方式确定接收的SSB为第一SSB，则终端设备可根据第一SSB进行接入和驻留。
通过该方法，处于空闲态的终端设备可根据第二SSB重选到第一小区。当第二区域内的空闲态终端设备均通过该方法重选到第一小区时，可提高群重选的效率。
并且，通过该方法，终端设备可根据第一偏移指示和接收到第二SSB的时间，接收来 自第一小区的第一SSB，从而无需终端设备盲检测第一SSB，也无需第二小区向终端设备发送第一SSB的配置信息，进而可降低终端设备的能耗，降低获取第一SSB的配置信息的开销。
本申请实施例提供了一种通信方法，该方法可应用于图3或图4所示的通信系统中。下面参阅图15所示的流程图，对该方法的流程进行具体说明。
S1501：在第一时间段内，第一小区在第三区域内发送数据信号和SSB。相应的，在第一时间段内，第三区域内的终端设备可接收来自第一小区的数据信号和SSB。
其中，第一小区可为第一卫星覆盖区域内的一个小区，第一卫星可覆盖至少一个区域。
例如，如图16所示，T4时刻属于第一时间段。在T4时刻，第一小区在波位1-波位4内发送数据信号和SSB。换句话说，第一小区的用于发送数据信号的波束和用于发送SSB的波束可覆盖波位1-波位4。其中，用于发送数据信号的波束可称为业务波束。用于发送SSB的波束可称为广播波束。第二卫星的第二小区在波位5-波位8内发送数据信号和SSB。换句话说，第二小区的业务波束和广播波束可覆盖波位5-波位8。第一卫星和第二卫星向右移动。
可选的，在图15所示方法中，SSB可为NR SSB，也可以为CD-SSB。SSB既可用于初始接入，又可用于小区重选或小区切换。
另外，在图15所示方法中，不同卫星的波束在波位级别上不重叠。
S1502：在第二时间段内，第一小区在第三区域内发送数据信号，在第四区域内发送SSB。相应的，在第二时间段内，第三区域内的终端设备可接收来自第一小区的数据信号，第四区域内的终端设备可接收来自第一小区的SSB。
其中，第二时间段为第一时间段之后的时间段。例如，第一时间段为0～5秒(s)，第二时间段为6～11s。
示例性的，如图16所示，T5时刻属于第二时间段。在T5时刻，第一小区在波位1-波位4内发送数据信号，在波位2、波位4、波位5和波位7内发送SSB。第二小区在波位5-波位8内发送数据信号，在波位6、波位8、波位9和波位10内发送SSB。这样，波位5和波位7内的终端设备可切换或重选到第一小区。
S1503：在第三时间段内，第一小区在第四区域内发送数据信号和SSB。相应的，在第三时间段内，第四区域内的终端设备可接收来自第一小区的数据信号和SSB。
其中，第三时间段为第二时间段之后的时间段。例如，第二时间段为6～11s，第三时间段为12～17s。第三时间段的起始时间可为第四区域内设定比例的终端设备完成小区切换或小区重选的时间。该设定比例例如为1/3。
示例性的，如图16所示，T6时刻属于第三时间段。在T6时刻，第一小区在波位2、波位4、波位5和波位7内发送数据信号和SSB。第二卫星的第二小区在波位6、波位8、波位9和波位10内发送数据信号和SSB。
通过该方法，第一小区在第四区域内发送数据信号之前，可先在第四区域内发送SSB。这样，在跳波束系统中，位于第四区域内的终端设备可在第一小区使用用于发送数据信号的波束覆盖第四区域之前，根据SSB进行广播信号质量的测量和下行同步，从而可在第一小区使用用于发送数据信号的波束覆盖第四区域时，无缝重选或切换至第一小区，提高小区重选和小区切换的效率。
可选的，在图15所示的方法中，终端设备可通过实现方式一或实现方式二确定第一 小区发送信号的时间与区域的对应关系。
实现方式一：终端设备分别获取第三配置信息和第四配置信息。其中，第三配置信息用于指示第一卫星发送数据信号的时间和区域的对应关系；第四配置信息用于指示第一卫星发送SSB的时间和区域的对应关系。
可选的，该实现方式一可包括步骤F1-F4：
F1：第一小区发送第三配置信息。相应的，终端设备接收第三配置信息。
其中，第一小区直接向终端设备发送第三配置信息。例如，终端设备位于波位2，第一小区可通过广播消息发送第三配置信息，或者通过单播消息向连接态的终端设备发送第三配置信息。
第一小区也可以通过其他小区发送向终端设备发送第三配置信息。例如，终端设备位于波位5，第一小区通过第二卫星的第二小区向终端设备转发第三配置信息。
可选的，第三配置信息可用于指示当前第一卫星发送数据信号的时间和区域的对应关系。例如，当前时间为T4时刻，T4时刻属于第一时间段，第三配置信息包括：第一时间段的指示信息和第三区域的指示信息。这表示在第一时间段内，第一小区可在第三区域内发送数据信号。其中，用于指示第一时间段的信息可为具体时间信息，例如0～5秒；用于指示第一时间段的信息也可为第一时间段的起始时间和时长，例如，起始时间为0秒，时长为5秒。第三区域的指示信息可为第三区域的标识或者第三区域内波位的标识。
第三配置信息还可用于表示当前和未来一段时间内第一卫星发送数据信号的时间和区域的对应关系。例如，当前时间为T4时刻，T4时刻属于第一时间段，第三配置信息包括：第一时间段的指示信息和第三区域的指示信息，第二时间段的指示信息和第三区域的指示信息，第三时间段的指示信息和第四区域的指示信息。这表示在第一时间段和第二时间段内，第一小区可在第三区域内发送数据信号，在第三时间段内，第一小区可在第四区域发送数据信号。其中，第二时间段的指示信息和第三时间段的指示信息的具体内容可参考对用于指示第一时间段的信息的说明。第四区域的指示信息可参考对第三区域的指示信息的说明。
F2：终端设备根据第三配置信息，接收来自第一小区的数据信号。
其中，终端设备可在第三配置信息指示的时间段内，在对应的区域内接收来自第一小区的数据信号。下面以第三配置信息包括：第一时间段的指示信息和第三区域的指示信息为例进行说明。若终端设备接收的第三配置信息包括：第一时间段的指示信息和第三区域的指示信息，则终端设备可在第一时间段内，在第三区域内接收来自第一小区的数据信号。
F3：第一小区发送第四配置信息。相应的，终端设备接收第四配置信息。
其中，终端设备接收第四配置信息的方式可参考步骤F1，只是将第三配置信息替换为第四配置信息，数据信号替换为SSB。
可选的，第四配置信息可用于指示当前第一卫星发送SSB的时间和区域的对应关系。例如，当前时间为T4时刻，T4时刻属于第一时间段，第四配置信息包括：第一时间段的指示信息和第三区域的指示信息。这表示在第一时间段内，第一小区可在第三区域内发送SSB。其中，用于指示第一时间段的信息和第三区域的指示信息可参考步骤F1，此处不再赘述。
第四配置信息还可用于表示当前和未来一段时间内第一卫星发送SSB的时间和区域的对应关系。例如，当前时间为T4时刻，T4时刻属于第一时间段，第四配置信息包括： 第一时间段的指示信息和第三区域的指示信息，第二时间段的指示信息和第四区域的指示信息，第三时间段的指示信息和第四区域的指示信息。这表示在第一时间段内，第一小区可在第三区域内发送SSB，在第二时间段和第三时间段内，第一小区在第四区域内发送SSB。其中，第二时间段的指示信息和第三时间段的指示信息的具体内容可参考对用于指示第一时间段的信息的说明。第四区域的指示信息可参考对第三区域的指示信息的说明。
F4：终端设备根据第四配置信息，接收来自第一小区的SSB。
其中，终端设备可在第四配置信息指示的时间段内，在对应的区域内接收来自第一小区的SSB。下面以第四配置信息包括：第一时间段的指示信息和第三区域的指示信息为例进行说明。若终端设备接收的第四配置信息包括：第一时间段的指示信息和第三区域的指示信息，则终端设备可在第一时间段内，在第三区域内接收来自第一小区的SSB。
本申请对步骤F1-F2和步骤F3-F4的顺序不作限定。
可选的，终端设备还可根据第三配置信息和第四配置信息确定第一小区能够为终端设备提供服务的时间(下面简称为服务时间)。在服务时间外，终端设备不检测来自第一小区的信号。例如，如图16所示，终端设备位于波位5。第三配置信息指示第一小区在0～5秒在波位1-波位4发送数据信号；第四配置信息指示第一小区在0～5秒在波位1-波位4发送SSB，在6～11秒在波位2、波位4、波位5和波位7发送SSB。则终端设备可确定0～6秒，第一小区未为终端设备提供服务，在该时间段内，终端设备不检测来自第一小区的信号。通过该方法，可降低终端设备的功耗。
实现方式二：终端设备获取第五配置信息和第二偏移指示。其中，第五配置信息用于指示第一卫星发送第一信号的时间和区域的对应关系；第二偏移指示用于指示第一卫星在第三区域或第四区域内发送第一信号的时间和发送第二信号的时间之间的时间间隔。其中，第一信号为数据信号，第二信号为SSB；或者，第一信号为SSB，第二信号为数据信号。
可选的，该实现方式二可包括步骤G1-G4：
G1：第一小区发送第五配置信息。相应的，终端设备接收第五配置信息。
其中，当第一信号为数据信号时，第五配置信息可为步骤F1中的第三配置信息，步骤G1可参考步骤F1。当第一信号为SSB时，第五配置信息可为步骤F3中的第四配置信息，步骤G2可参考步骤F3。
G2：终端设备根据第五配置信息，接收来自第一小区的第一信号。
当第一信号为数据信号时，步骤G2可参考步骤F2。当第一信号为SSB时，步骤G2可参考步骤F4。
G3：第一小区发送第二偏移指示。相应的，终端设备接收第二偏移指示。
其中，第一小区直接向终端设备发送第二偏移指示。例如，终端设备位于波位2，第一小区可通过广播消息发送第二偏移指示，或者通过单播消息向连接态的终端设备发送第二偏移指示。
第一小区也可以通过其他小区发送向终端设备发送第二偏移指示。例如，终端设备位于波位5，第一小区通过第二卫星的第二小区向终端设备转发第二偏移指示。
G4：终端设备根据第五配置信息和第二偏移指示，接收来自第一小区的第二信号。
下面以第一信号为SSB，第二信号为数据信号为例进行说明。例如，第五配置信息包括：第二时间段的指示信息和第四区域的指示信息。若第二时间段为6～11秒，第二偏移指示所指示的时间偏移为6秒，则终端设备可确定在12～17秒内在第四区域接收来自第一 小区的数据信号。
通过该实现方式，终端设备可根据第一信号的配置信息和第二偏移指示，确定接收第二信号的时间，无需接收第二信号的配置信息，从而可降低开销。
可选的，与实现方式一类似，终端设备也可根据第五配置信息和第二偏移指示确定第一小区能够为终端设备提供服务的时间(下面简称为服务时间)。在服务时间外，终端设备不检测来自第一小区的信号。通过该方法，可降低终端设备的功耗。
可选的，图15所示方法还包括步骤H1-H2：
H1：第一小区发送用于第四时间段的指示信息。相应的，终端设备接收用于第四时间段的指示信息。
其中，在第四时间段内，第一小区的第一发送波束可与终端设备的第一接收波束配对。换句话说，第四时间段为第一发送波束和第一接收波束配对的时间段。
其中，第一小区可直接向终端设备发送第四时间段的指示信息。例如，终端设备位于波位2，第一小区可通过广播消息发送第四时间段的指示信息，或者通过单播消息向连接态的终端设备发送第四时间段的指示信息。
第一小区也可以通过其他小区发送向终端设备发送第四时间段的指示信息。例如，终端设备位于波位5，第一小区通过第二卫星的第二小区向终端设备转发第四时间段的指示信息。
另外，第四时间段的指示信息的具体内容可参考步骤F1中的第一时间段的指示信息，只是将第一时间段替换为第四时间段，此处不再赘述。
G2：在第四时间段内，终端设备可通过第一接收波束接收来自第一小区的数据信号和/或SSB。
通过该方法，终端设备在第一小区指示的第四时间段内，通过第一接收波束接收来自第一小区的数据信号和/或SSB。在第四时间段内，第一接收波束与第一小区的第一发送波束配对，因此，该方法可提高通信质量。并且，通过该方法，终端设备无需检测哪个波束能够与第一小区的发送波束配对，从而可提高通信效率。
基于与图7A至图16方法实施例相同的技术构思，本申请实施例通过图17提供了一种通信装置，可用于执行上述方法实施例中相关步骤的功能。所述功能可以通过硬件实现，也可以通过软件或者硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。该通信装置的结构如图17所示，包括通信单元1701和处理单元1702。所述通信装置1700可以应用于图3或图4所示的通信系统中的网络设备、卫星或终端设备，并可以实现以上本申请实施例以及实例提供的通信方法。下面对所述通信装置1700中的各个单元的功能进行介绍。
所述通信单元1701，用于接收和发送数据。所述通信单元1701可以通过收发器实现，例如，移动通信模块。其中，移动通信模块可以包括至少一个天线、至少一个滤波器，开关，功率放大器，低噪声放大器(low noise amplifier，LNA)等。
所述处理单元1702可用于支持所述通信装置1700执行上述方法实施例中的处理动作。所述处理单元1702可以是通过处理器实现。例如，所述处理器可以为中央处理单元(central processing unit，CPU)，还可以是其它通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现场可编程门阵列(field  programmable gate array，FPGA)或者其它可编程逻辑器件、晶体管逻辑器件，硬件部件或者其任意组合。通用处理器可以是微处理器，也可以是任何常规的处理器。
在一种实施方式中，所述通信装置1700应用于图3或图4所示的通信系统中的网络设备或卫星。下面对该实施方式中的所述处理单元1702的具体功能进行介绍。
所述处理单元1702，用于：通过所述通信单元1701发送第一SSB，第一SSB为用于初始接入的SSB；通过所述通信单元1701发送第二SSB，第二SSB为用于小区切换或小区重选的SSB。
可选的，第一SSB不用于小区切换或小区重选，第二SSB不用于初始接入。
可选的，所述处理单元1702具体用于：通过所述通信单元1701在第一区域内发送第一SSB；通过所述通信单元1701在第二区域内发送第二SSB。
可选的，所述处理单元1702具体用于：通过所述通信单元1701向第二小区发送配置信息，配置信息用于指示第一小区发送第二SSB的配置。
可选的，第一SSB的发送时间和第二SSB的发送时间不重叠。
可选的，第一SSB的发送周期小于第二SSB的发送周期。
可选的，第一SSB和第二SSB均为NR SSB。
可选的，第一SSB为CD-SSB，第二SSB为NCD-SSB。
可选的，NCD-SSB与用于切换的资源和/或用于切换的随机接入前导对应。
可选的，所述处理单元1702具体用于：通过所述通信单元1701向第二小区发送第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量。
可选的，所述处理单元1702具体用于：更新第一小区发送第二SSB的配置，不更新第一小区的系统信息块SIB。
在另一种实施方式中，所述通信装置1700应用于图3或图4所示的通信系统中的终端设备。下面对该实施方式中的所述处理单元1702的具体功能进行介绍。
所述处理单元1702，用于：通过所述通信单元1701接收来自第二小区的第三SSB，第三SSB为用于初始接入的SSB；根据第三SSB，接入到第二小区；通过所述通信单元1701接收来自第一小区的第二SSB，第二SSB为用于小区切换或小区重选的SSB；通过所述通信单元1701根据第二SSB，向第二小区发送测量报告。
可选的，所述处理单元1702具体用于：通过所述通信单元1701接收来自第二小区的配置信息，配置信息用于指示第一小区发送第二SSB的配置；根据配置信息，通过所述通信单元1701接收来自第一小区的第二SSB。
可选的，第二SSB为NCD-SSB，所述处理单元1702具体用于：通过所述通信单元1701使用与NCD-SSB对应的用于切换的资源和/或用于切换的随机接入前导，与第一小区进行通信。
可选的，所述处理单元1702具体用于：通过所述通信单元1701接收来自第二小区的切换命令，切换命令用于指示终端设备切换到第一小区；通过所述通信单元1701接收来自第一小区的第一SSB，第一SSB为用于初始接入的SSB。
可选的，所述处理单元1702具体用于：通过所述通信单元1701接收第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之 间的时间间隔；根据第一偏移指示和接收到第二SSB的时间，通过所述通信单元1701接收来自第一小区的第一SSB。
可选的，第一SSB不用于小区切换或小区重选，第二SSB不用于初始接入。
可选的，第一SSB的发送时间和第二SSB的发送时间不重叠。
可选的，第一SSB的发送周期小于第二SSB的发送周期。
可选的，第一SSB和第二SSB均为NR SSB。
可选的，第一SSB为CD-SSB，第二SSB为NCD-SSB。
在又一种实施方式中，所述通信装置1700应用于图3或图4所示的通信系统中的终端设备。下面对该实施方式中的所述处理单元1702的具体功能进行介绍。
所述处理单元1702，用于：通过所述通信单元1701接收来自第一小区的第二SSB，第二SSB为用于小区切换或小区重选的SSB；通过所述通信单元1701接收第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量，第一SSB为用于初始接入的SSB；根据第二SSB，重选到第一小区；根据接收到第二SSB的时间和第一偏移指示，通过所述通信单元1701接收来自第一小区的第一SSB。
可选的，第一SSB不用于小区切换或小区重选，第二SSB不用于初始接入。
可选的，第一SSB的发送时间和第二SSB的发送时间不重叠。
可选的，第一SSB的发送周期小于第二SSB的发送周期。
可选的，第一SSB和第二SSB均为NR SSB。
可选的，第一SSB为CD-SSB，第二SSB为NCD-SSB。
需要说明的是，本申请以上实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器(processor)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
基于相同的技术构思，本申请实施例通过图18所示提供了一种通信装置，可用于执行上述方法实施例中相关的步骤。所述通信装置可以应用于图3或图4所示的通信系统中的网络设备、卫星或终端设备，可以实现以上本申请实施例以及实例提供的通信方法，具有图17所示的通信装置的功能。参阅图18所示，所述通信装置1800包括：通信模块1801、处理器1802以及存储器1803。其中，所述通信模块1801、所述处理器1802以及所述存 储器1803之间相互连接。
可选的，所述通信模块1801、所述处理器1802以及所述存储器1803之间通过总线1804相互连接。所述总线1804可以是外设部件互连标准(peripheral component interconnect，PCI)总线或扩展工业标准结构(extended industry standard architecture，EISA)总线等。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图18中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
所述通信模块1801，用于接收和发送数据，实现与其他设备之间的通信交互。例如，所述通信模块1801可以通过物理接口、通信模块、通信接口、输入输出接口实现。
所述处理器1802可用于支持所述通信装置1800执行上述方法实施例中的处理动作。当所述通信装置1800用于实现上述方法实施例时，处理器1802还可用于实现上述处理单元1702的功能。所述处理器1802可以是CPU，还可以是其它通用处理器、DSP、ASIC、FPGA或者其它可编程逻辑器件、晶体管逻辑器件，硬件部件或者其任意组合。通用处理器可以是微处理器，也可以是任何常规的处理器。
在一种实施方式中，所述通信装置1800应用于图3或图4所示的通信系统中的网络设备或卫星。所述处理器1802具体用于：通过所述通信模块1801发送第一SSB，第一SSB为用于初始接入的SSB；通过所述通信模块1801发送第二SSB，第二SSB为用于小区切换或小区重选的SSB。
在另一种实施方式中，所述通信装置1800应用于图3或图4所示的通信系统中的终端设备。所述处理器1802具体用于：通过所述通信模块1801接收来自第二小区的第三SSB，第三SSB为用于初始接入的SSB；根据第三SSB，接入到第二小区；通过所述通信模块1801接收来自第一小区的第二SSB，第二SSB为用于小区切换或小区重选的SSB；通过所述通信模块1801根据第二SSB，向第二小区发送测量报告。
在又一种实施方式中，所述通信装置1800应用于图3或图4所示的通信系统中的终端设备。所述处理器1802具体用于：通过所述通信模块1801接收来自第一小区的第二SSB，第二SSB为用于小区切换或小区重选的SSB；通过所述通信模块1801接收第一偏移指示，第一偏移指示用于指示第二SSB的发送时间和与第二SSB相邻的第一SSB的发送时间之间的时间偏移量，第一SSB为用于初始接入的SSB；根据第二SSB，重选到第一小区；根据接收到第二SSB的时间和第一偏移指示，通过所述通信模块1801接收来自第一小区的第一SSB。
所述处理器1802的具体功能可以参考以上本申请实施例以及实例提供的通信方法中的描述，以及图17所示本申请实施例中对所述通信装置1700的具体功能描述，此处不再赘述。
所述存储器1803，用于存放程序指令和数据等。具体地，程序指令可以包括程序代码，该程序代码包括计算机操作指令。存储器1803可能包含RAM，也可能还包括非易失性存储器(non-volatile memory)，例如至少一个磁盘存储器。处理器1802执行存储器1803所存放的程序指令，并使用所述存储器1803中存储的数据，实现上述功能，从而实现上述本申请实施例提供的通信方法。
可以理解，本申请图18中的存储器1803可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是ROM、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、 电可擦除可编程只读存储器(Electrically EPROM，EEPROM)或闪存。易失性存储器可以是RAM，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(Static RAM，SRAM)、动态随机存取存储器(Dynamic RAM，DRAM)、同步动态随机存取存储器(Synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(Double Data Rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(Enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(Synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(Direct Rambus RAM，DR RAM)。应注意，本文描述的系统和方法的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
基于以上实施例，本申请实施例还提供了一种计算机程序，当所述计算机程序在计算机上运行时，使得所述计算机执行以上实施例提供的方法。
基于以上实施例，本申请实施例还提供了一种计算机可读存储介质，该计算机可读存储介质中存储有计算机程序，所述计算机程序被计算机执行时，使得计算机执行以上实施例提供的方法。
其中，存储介质可以是计算机能够存取的任何可用介质。以此为例但不限于：计算机可读介质可以包括RAM、ROM、EEPROM、CD-ROM或其他光盘存储、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质。
基于以上实施例，本申请实施例还提供了一种芯片，所述芯片用于读取存储器中存储的计算机程序，实现以上实施例提供的方法。
基于以上实施例，本申请实施例提供了一种芯片系统，该芯片系统包括处理器，用于支持计算机装置实现以上实施例中各设备所涉及的功能。在一种可能的设计中，所述芯片系统还包括存储器，所述存储器用于保存该计算机装置必要的程序和数据。该芯片系统，可以由芯片构成，也可以包含芯片和其他分立器件。
综上所述，本申请实施例提供了一种通信方法及装置，在该方法中，第一小区可发送第一SSB，第一SSB为用于初始接入的SSB。第一小区还可发送第二SSB，第二SSB为用于小区切换或小区重选的SSB。通过该方法，第一小区可分别发送用于初始接入的第一SSB和用于小区切换或小区重选的第二SSB。这样，当需要终端设备接入第一小区时，第一小区可发送第一SSB；当需要终端设备切换或重选到第一小区时，第一小区可发送第二SSB，从而可按需发送SSB，降低发送SSB的开销，提高终端设备测量SSB的效率。
在本申请的各个实施例中，如果没有特殊说明以及逻辑冲突，不同的实施例之间的术语和/或描述具有一致性、且可以相互引用，不同的实施例中的技术特征根据其内在的逻辑关系可以组合形成新的实施例。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指 令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (25)

  1. 一种通信方法，应用于第一小区，其特征在于，包括：
    发送第一同步信号块SSB，所述第一SSB为用于初始接入的SSB；
    发送第二SSB，所述第二SSB为用于小区切换或小区重选的SSB。
  2. 如权利要求1所述的方法，其特征在于，所述第一SSB不用于小区切换或小区重选，所述第二SSB不用于初始接入。
  3. 如权利要求1或2所述的方法，其特征在于，发送第一SSB，包括：在第一区域内发送所述第一SSB；
    发送第二SSB，包括：在第二区域内发送所述第二SSB。
  4. 如权利要求1-3任一项所述的方法，其特征在于，所述方法还包括：
    向第二小区发送配置信息，所述配置信息用于指示所述第一小区发送所述第二SSB的配置。
  5. 如权利要求1-4任一项所述的方法，其特征在于，所述第一SSB的发送时间和所述第二SSB的发送时间不重叠。
  6. 如权利要求1-5任一项所述的方法，其特征在于，所述第一SSB的发送周期小于所述第二SSB的发送周期。
  7. 如权利要求1-6任一项所述的方法，其特征在于，所述第一SSB和所述第二SSB均为新无线NR SSB。
  8. 如权利要求1-7任一项所述的方法，其特征在于，所述第一SSB为小区定义同步信号块CD-SSB，所述第二SSB为非小区定义同步信号块NCD-SSB。
  9. 如权利要求8所述的方法，其特征在于，所述NCD-SSB与用于切换的资源和/或用于切换的随机接入前导对应。
  10. 如权利要求1-9任一项所述的方法，其特征在于，所述方法还包括：
    向第二小区发送第一偏移指示，所述第一偏移指示用于指示所述第二SSB的发送时间和与所述第二SSB相邻的第一SSB的发送时间之间的时间偏移量。
  11. 如权利要求1-10任一项所述的方法，其特征在于，所述方法还包括：
    更新所述第一小区发送所述第二SSB的配置，不更新所述第一小区的系统信息块SIB。
  12. 一种通信方法，应用于终端设备，其特征在于，包括：
    接收来自第二小区的第三同步信号块SSB，所述第三SSB为用于初始接入的SSB；
    根据所述第三SSB，接入到所述第二小区；
    接收来自第一小区的第二SSB，所述第二SSB为用于小区切换或小区重选的SSB；
    根据所述第二SSB，向所述第二小区发送测量报告。
  13. 一种通信方法，应用于终端设备，其特征在于，包括：
    接收来自第一小区的第二同步信号块SSB，所述第二SSB为用于小区切换或小区重选的SSB；
    接收第一偏移指示，所述第一偏移指示用于指示所述第二SSB的发送时间和与所述第二SSB相邻的第一SSB的发送时间之间的时间偏移量，所述第一SSB为用于初始接入的SSB；
    根据所述第二SSB，重选到所述第一小区；
    根据接收到所述第二SSB的时间和所述第一偏移指示，接收来自所述第一小区的第一SSB。
  14. 如权利要求12所述的方法，其特征在于，所述方法还包括：
    接收来自所述第二小区的配置信息，所述配置信息用于指示所述第一小区发送所述第二SSB的配置；
    接收来自第一小区的第二SSB，包括：根据所述配置信息，接收来自所述第一小区的所述第二SSB。
  15. 如权利要求12或14所述的方法，其特征在于，所述第二SSB为NCD-SSB，所述方法还包括：
    使用与所述NCD-SSB对应的用于切换的资源和/或用于切换的随机接入前导，与所述第一小区进行通信。
  16. 如权利要求12、14或15所述的方法，其特征在于，所述方法还包括：
    接收来自所述第二小区的切换命令，所述切换命令用于指示所述终端设备切换到所述第一小区；
    接收来自所述第一小区的第一SSB，所述第一SSB为用于初始接入的SSB。
  17. 如权利要求16所述的方法，其特征在于，所述方法还包括：
    接收第一偏移指示，所述第一偏移指示用于指示所述第二SSB的发送时间和与所述第二SSB相邻的第一SSB的发送时间之间的时间间隔；
    接收来自所述第一小区的第一SSB，包括：根据所述第一偏移指示和接收到所述第二SSB的时间，接收来自所述第一小区的所述第一SSB。
  18. 如权利要求13、16或17所述的方法，其特征在于，所述第一SSB不用于小区切换或小区重选，所述第二SSB不用于初始接入。
  19. 如权利要求13、16-18任一项所述的方法，其特征在于，所述第一SSB的发送时间和所述第二SSB的发送时间不重叠。
  20. 如权利要求13、16-19任一项所述的方法，其特征在于，所述第一SSB的发送周期小于所述第二SSB的发送周期。
  21. 如权利要求13、16-20任一项所述的方法，其特征在于，所述第一SSB和所述第二SSB均为新无线NR SSB。
  22. 如权利要求13、16-21任一项所述的方法，其特征在于，所述第一SSB为小区定义同步信号块CD-SSB，所述第二SSB为非小区定义同步信号块NCD-SSB。
  23. 一种通信装置，其特征在于，包括处理器和存储器，所述处理器和所述存储器耦合，所述处理器用于执行所述存储器中存储的计算机程序指令，以使如权利要求1至11中任一项所述的方法被实现。
  24. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质中存储有计算机程序，当所述计算机程序在计算机上运行时，使得如权利要求1-11任一项所述的方法被实现。
  25. 一种芯片，其特征在于，所述芯片与存储器耦合，所述芯片读取所述存储器中存储的计算机程序，以使如权利要求1-11任一项所述的方法被实现。
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