WO2021063382A1 - 卫星通信方法和相关通信设备 - Google Patents

卫星通信方法和相关通信设备 Download PDF

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Publication number
WO2021063382A1
WO2021063382A1 PCT/CN2020/119184 CN2020119184W WO2021063382A1 WO 2021063382 A1 WO2021063382 A1 WO 2021063382A1 CN 2020119184 W CN2020119184 W CN 2020119184W WO 2021063382 A1 WO2021063382 A1 WO 2021063382A1
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Prior art keywords
sequence
frequency
random access
cyclic prefix
subsequence
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PCT/CN2020/119184
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English (en)
French (fr)
Inventor
徐晨蕾
罗禾佳
周建伟
王晓鲁
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华为技术有限公司
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Priority to EP20870531.9A priority Critical patent/EP4027737A4/en
Publication of WO2021063382A1 publication Critical patent/WO2021063382A1/zh
Priority to US17/707,815 priority patent/US20220224463A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0016—Time-frequency-code
    • H04L5/0021—Time-frequency-code in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay
    • H04B7/18513—Transmission in a satellite or space-based system
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H04W74/006—Transmission of channel access control information in the downlink, i.e. towards the terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • This application relates to the field of communication technology, in particular to satellite communication methods and related communication equipment.
  • Satellite communication has significant advantages such as global coverage, long-distance transmission, flexible networking, convenient deployment and freedom from geographical conditions, so it has been widely used in maritime communications, positioning and navigation, disaster relief, scientific experiments, video broadcasting, and ground Observation and other fields.
  • the fifth-generation mobile network (5G) on the ground will have a complete industrial chain, a huge user group, and a flexible and efficient application service model. Therefore, the integration of satellite communication systems and 5G networks to complement each other's strengths to form a seamless global sea, land, air, and sky integrated communication network to meet the ubiquitous business needs of users is the future of communication development An important direction.
  • the satellite communication system uses Non-Geostationary Earth Orbit (NGEO) satellites.
  • NGEO Non-Geostationary Earth Orbit
  • the satellite mobile communication system can be divided into a geostationary (GEO, Earth Orbit) system, a medium orbit (MEO, Medium Earth Orbit) satellite communication system, and a low orbit (LEO, Low Earth Orbit) satellite communication system. system.
  • GEO geostationary Earth Orbit
  • MEO Medium Earth Orbit
  • LEO Low Earth Orbit
  • the carrier frequency offset will greatly deteriorate the performance of the communication system.
  • the main sources of carrier frequency deviation are: the frequency error of the crystal oscillator used at both ends of the communication system and the Doppler frequency deviation of the wireless channel.
  • the carrier frequency offset is mainly derived from crystal oscillator errors.
  • the Doppler frequency offset is also an important part of the carrier frequency offset.
  • satellite mobile communication systems especially low-orbit satellite mobile communication systems, in addition to the carrier frequency offset caused by the crystal oscillator error, there is also a large Doppler frequency offset in the satellite-to-earth link.
  • the embodiment of the present application provides a satellite communication method and related communication equipment.
  • an embodiment of the present application provides a satellite communication method, including:
  • the random access preamble sequence includes a cyclic prefix, a sequence part, and a guard interval, and the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation.
  • the sequence is obtained based on the ZC sequence and the mask sequence; and the random access preamble sequence is output.
  • u is the root number of the ZC sequence
  • x u (i) represents a piece of data in the original ZC sequence
  • N zc is the length of the ZC sequence
  • x u, v (n) represents a piece of data in the ZC sequence that has undergone cyclic shift processing
  • C v is the cyclic shift
  • c(n) is an element in the mask sequence, Represents a piece of data in the frequency domain sequence.
  • the mask sequence is an m sequence, an M sequence, or a Gold sequence, wherein the elements in the mask sequence are a scaling value of 1, -1 or 1, -1.
  • the mask sequence is a mask sequence common to the entire network
  • the mask sequence is a mask sequence of a random access preamble agreed by all base stations and terminals, and all base stations and terminals use masks containing the same elements. sequence.
  • the mask sequence is a mask sequence common to a cell or satellite beam, and the generation of the mask sequence is related to at least one cell or satellite beam specific parameter, where the cell or satellite beam specific parameter includes the following parameters One or more of: cell or satellite beam index number, data subcarrier width index number, synchronization signal block index number or bandwidth part index number;
  • the mask sequence is a sequence related to random access time-frequency resources, and the generation of the mask sequence is related to at least one random access time-frequency resource related parameter, where the random access time-frequency resource parameter includes the following One or more of the parameters: the start symbol of the time-frequency resource, the start time slot number, the frequency domain resource number, or the uplink carrier number.
  • the sequence part includes at least one subsequence A, and in addition, the sequence part may also include at least one subsequence B.
  • the subsequence A includes at least one preamble symbol, wherein the subsequence B includes at least one preamble symbol, and the preamble symbol included in the subsequence A is different from the preamble symbol included in the subsequence B; the subsequence A
  • the frequency domain sequence Za is obtained through frequency domain resource mapping and time-frequency transformation, and the frequency domain sequence Za is obtained based on the ZC sequence and the mask sequence.
  • the interval between any two subsequences B is at least greater than or equal to Indicates rounding up, where, Indicates the integer number of leading symbols contained in the cyclic prefix, Represents the decimal leading symbols contained in the cyclic prefix.
  • each subsequence A and each subsequence B are respectively greater than or equal to the length of the cyclic prefix.
  • the number of cyclic prefixes included in the random access preamble sequence is one
  • the subsequence A and the subsequence B are located between the cyclic prefix and the guard interval, or the time domain superimposed sequence of the subsequence A and the subsequence B is located between the cyclic prefix and the guard interval.
  • the random access preamble sequence includes a first cyclic prefix and a second cyclic prefix
  • At least one of the subsequences A is located between the first cyclic prefix and the second cyclic prefix, and at least one of the subsequences B is located between the second cyclic prefix and the guard interval;
  • At least one of the subsequences B is located between the first cyclic prefix and the second cyclic prefix, and at least one of the subsequences A is located between the second cyclic prefix and the guard interval;
  • the first cyclic prefix and the second cyclic prefix include at least one of the subsequence A and at least one of the subsequence B that alternately appear.
  • an embodiment of the present application provides a satellite communication device, including:
  • the sending unit is used to generate a random access preamble sequence, the random access preamble sequence includes a cyclic prefix, a sequence part and a guard interval, and the sequence part is obtained from the frequency domain sequence through frequency domain resource mapping and time-frequency transformation, so The frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • the output unit outputs the random access preamble sequence.
  • an embodiment of the present application provides a satellite communication method, including:
  • the random access preamble sequence includes a cyclic prefix, a sequence part, and a guard interval, the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation, and the frequency domain sequence is based on The ZC sequence and the mask sequence are obtained.
  • the frequency offset estimation indication is carried in the frequency offset estimation value feedback field of the medium access control random access response MAC RAR; or, the frequency offset estimation indication is carried in the random access wireless network temporary identifier RA-RNTI.
  • an embodiment of the present application provides a satellite communication device, including:
  • the communication unit is configured to receive a random access preamble sequence; the random access preamble sequence includes a cyclic prefix, a sequence part and a guard interval, and the sequence part is obtained from the frequency domain sequence through frequency domain resource mapping and time-frequency transformation, so The frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • the detection unit is configured to perform uplink time-frequency estimation based on the received random access preamble sequence to obtain a frequency offset estimation value Consists of frequency deviation caused by crystal error and/or Doppler frequency deviation.
  • the communication unit is further configured to send a frequency offset estimation indication to the terminal, where the frequency offset estimation indication is used to indicate the frequency offset estimation value
  • the frequency offset estimation indication is carried in the frequency offset estimation value feedback field of the medium access control random access response MAC RAR; or, the frequency offset estimation indication is carried in the random access wireless network temporary identifier RA-RNTI.
  • an embodiment of the present application also provides a satellite communication device, including: a processor and a memory coupled to each other;
  • the processor is configured to call a computer program stored in the memory to execute part or all of the steps of any method of the first aspect or the third aspect.
  • embodiments of the present application also provide a computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to complete part of the methods in the above aspects Or all steps.
  • the embodiments of the present application also provide a computer program product including instructions, which when the computer program product runs on a user equipment, cause the satellite communication device to perform some or all of the steps of the above methods.
  • an embodiment of the present application further provides a communication device, including: at least one input terminal, a signal processor, and at least one output terminal; wherein the signal processor is used to execute any one of the above aspects Some or all of the steps.
  • an embodiment of the present application also provides a communication device, including: an input interface circuit, a logic circuit, and an output interface circuit; wherein the logic circuit is used to perform part or all of the steps of any one of the above aspects .
  • Fig. 1-A is a schematic diagram of the architecture of a communication system provided by an embodiment of the present application.
  • Fig. 1-B is a schematic diagram of a satellite communication scenario provided by an embodiment of the present application.
  • Fig. 2 is a schematic flowchart of a satellite communication method provided by an embodiment of the present application.
  • FIG. 3 is a schematic diagram of a sending mechanism of a random access preamble sequence provided by an embodiment of the present application.
  • FIGS. 4-A to 4-B are schematic diagrams of a mask restoration method provided by an embodiment of the present application.
  • Fig. 4-C to Fig. 4-F are several schematic diagrams of the detection performance of the random access preamble sequence provided by the embodiments of the present application.
  • Fig. 4-G is the intention of the indication mapping table provided by an embodiment of the present application.
  • Fig. 4-H is the intention of the index table of the indication form provided by the embodiment of the present application.
  • FIG. 5-A to FIG. 5-F are schematic diagrams of the format of the random access preamble sequence provided by an embodiment of the present application.
  • Fig. 6-A is a schematic flowchart of another satellite communication method provided by an embodiment of the present application.
  • Figure 6-B is a schematic diagram of a message format provided by an embodiment of the present application.
  • Fig. 7 is a schematic structural diagram of a satellite communication device provided by an embodiment of the present application.
  • Fig. 8 is a schematic structural diagram of another satellite communication device provided by an embodiment of the present application.
  • Fig. 9 is a schematic structural diagram of another satellite communication device provided by an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of another satellite communication device provided by an embodiment of the present application.
  • Fig. 11 is a schematic structural diagram of another satellite communication device provided by an embodiment of the present application.
  • FIG. 1-A is a schematic diagram of a 5G network architecture exemplified in an embodiment of the present application.
  • the 5G network splits certain functional network elements of the 4G network (such as mobility management entities (MME, Mobility Management Entity), etc.), and defines an architecture based on a service-oriented architecture.
  • MME mobility management entities
  • MMF Access and Mobility Management Function
  • SMF Session Management Function
  • the user terminal accesses the data network (DN, Data Network) and so on by accessing the operator's network, and uses the service provided by the operator or a third party on the DN.
  • DN Data Network
  • the user terminal, user equipment, terminal device, or terminal in the embodiments of the present application may be collectively referred to as UE. That is, unless otherwise specified, the UE described later in the embodiments of the present application can be replaced with a user terminal, a user equipment, a terminal device, or a terminal, and of course they can also be interchanged.
  • the Access and Mobility Management Function is a control plane function in the 3GPP network, which is mainly responsible for the access control and mobility management of the UE's access to the operator's network.
  • the security anchor function SEAF, Security Anchor Function
  • SEAF may be deployed in the AMF, or the SEAF may also be deployed in another device different from the AMF.
  • FIG. 1-A the SEAF is deployed in the AMF as an example.
  • SEAF and AMF can be collectively referred to as AMF.
  • the session management function is a control plane function in the 3GPP network. Among them, the SMF is mainly used to manage the data packet (PDU, Packet Data Unit) session of the UE.
  • the PDU session is a channel used to transmit PDUs.
  • the UE can send PDUs to each other through the PDU session and the DN.
  • SMF is responsible for management work such as the establishment, maintenance and deletion of PDU sessions.
  • DN Data Network
  • PDN Packet Data Network
  • a certain DN is a private network of a smart factory, sensors installed on the smart factory workshop play the role of UE, and a control server for the sensors is deployed in the DN.
  • the UE communicates with the control server, and after obtaining the instruction of the control server, the UE can transmit the collected data to the control server according to the instruction.
  • a DN is a company's internal office network, and the terminal used by the company's employees can play the role of a UE, and this UE can access the company's internal information and other resources.
  • the unified data management entity (UDM, Unified Data Management) is also a control plane function in the 3GPP network.
  • UDM is mainly responsible for storing the subscription data, credentials and persistent identity of the subscriber (UE) in the 3GPP network.
  • SUPI Subscriber Permanent Identifier
  • These data can be used for authentication and authorization of the UE to access the operator's 3GPP network.
  • the authentication server function (AUSF, Authentication Server Function) is also a control plane function in the 3GPP network, and the AUSF is mainly used for the first-level authentication (that is, the 3GPP network authenticates its subscribers).
  • the Network Exposure Function is also a control plane function in the 3GPP network.
  • NEF is mainly responsible for opening the external interface of the 3GPP network to third parties in a safe manner.
  • SMF and other functions need to communicate with third-party network elements, NEF can be used as a communication relay.
  • NEF can translate internal and external logos. For example, when the SUPI of the UE is sent from the 3GPP network to a third party, the NEF can translate the SUPI into its corresponding external identity (ID, Identity). Conversely, NEF can translate the external identity ID into the corresponding SUPI when it is sent to the 3GPP network.
  • ID external identity
  • the network storage function (NRF, Network Repository Function) is also a control plane function in the 3GPP network, which is mainly responsible for storing the configuration service profile of the accessible network function (NF) and providing the network for other network elements Functional discovery service.
  • User Plane Function is the gateway for the communication between the 3GPP network and the DN.
  • the Policy Control Function (PCF, Policy Control Function) is a control plane function in the 3GPP network, which is used to provide the SMF with the policy of the PDU session.
  • Policies can include billing, quality of service (QoS, Quality of Service), authorization-related policies, and so on.
  • Access Network is a sub-network of the 3GPP network. To access the 3GPP network, the UE first needs to go through the AN. In the wireless access scenario, AN is also called Radio Access Network (RAN, Radio Access Network), so the two terms RAN and AN are often mixed without distinction.
  • RAN Radio Access Network
  • 3GPP network refers to a network that complies with 3GPP standards. Among them, the part except UE and DN in Figure 1-A can be regarded as a 3GPP network.
  • 3GPP networks are not limited to 5G networks defined by 3GPP, but can also include 2G, 3G, and 4G networks. Usually 3GPP networks are operated by operators.
  • N1, N2, N3, N4, N6, etc. in the architecture shown in FIG. 1-A respectively represent reference points between related entities/network functions. Nausf, Namf... etc. respectively represent service-oriented interfaces of related network functions.
  • 3GPP networks and non-3GPP networks may coexist, and some network elements in the 5G network may also be used in some non-5G networks.
  • terrestrial 5G will have a complete industrial chain, a huge user group, and a flexible and efficient application service model. Therefore, the satellite communication system and the 5G network are merged with each other and complement each other to form a seamless global sea, land, air, and space integrated integrated communication network to meet the ubiquitous business needs of users. It is an important part of the future communication development. Important direction.
  • FIG. 1-B illustrates a schematic diagram of a satellite communication scenario.
  • a protocol stack compatible with the 3GPP LTE/NR protocol can be used.
  • the user terminal is an ordinary mobile terminal or a dedicated terminal, and the transmission process also follows the LTE/NR protocol.
  • the solution discussed in this application is also applicable to the ground mobile communication scenarios defined by 3GPP LTE/NR, and is more applicable to high-speed mobile communication scenarios such as high-speed trains and airplanes.
  • the satellites run relatively fast, which makes the signal produce a large range of fast time-varying Doppler frequency deviation during the transmission process.
  • the main factor causing the time-frequency synchronization problem is the frequency offset caused by the Doppler frequency offset and the crystal error.
  • the traditional time-frequency estimation algorithm can only estimate two frequencies in the downlink synchronization. The superimposed value of the deviation, namely f d + f e , where f d represents the Doppler frequency deviation, and f e represents the frequency deviation caused by the crystal oscillator error.
  • the reasonable frequency offset compensation method should be the terminal side to compensate the transmitted uplink signal -f d + f e , that is, the Doppler frequency offset
  • the negative compensation method is adopted, and the positive compensation method is adopted for the frequency deviation caused by the crystal error. If the user terminal directly uses the frequency offset estimation result of the downlink synchronization to perform frequency offset compensation on the uplink transmission signal, a frequency offset of 2f e (negative compensation) or 2f d (positive compensation) will be introduced into the uplink signal.
  • the satellite orbit height of the low-orbit satellite communication system is 600km.
  • the satellite base station uses the Doppler frequency offset at the center of the beam as the pre-compensation value to compensate for the partial Doppler frequency offset of the downlink data.
  • the residual Doppler frequency offset of the terminal at the edge of the under-satellite beam with a radius of 200km in this system is 4.14ppm
  • the crystal oscillator error of the terminal is 5ppm
  • the crystal oscillator error of the satellite base station is ignored.
  • the maximum uplink residual frequency offset is about 8.3ppm, that is, the residual frequency offset is 16.6kHz when the carrier is 2GHz, and the residual frequency offset is 249kHz when the carrier is 30GHz; if negative In the compensation method, the maximum upstream residual frequency deviation is about 10ppm, that is, when the carrier is 2GHz, the residual frequency deviation is 20kHz, and when the carrier is 30GHz, the residual frequency deviation is 300kHz.
  • the uplink residual frequency offset of the satellite mobile communication system is much larger than that of the terrestrial communication system, and a larger residual frequency offset will have a serious impact on the random access preamble specified in the LTE/NR protocol, leading to its uplink synchronization performance Decrease, and even make the function of uplink synchronization completely invalid.
  • the random access preamble sequence provided by the embodiment of the application includes a cyclic prefix, a sequence part, and a guard interval.
  • the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation.
  • the frequency domain sequence is based on the ZC sequence and
  • the mask sequence is obtained.
  • a satellite communication method may include:
  • the random access preamble sequence includes a cyclic prefix, a sequence part, and a guard interval, and the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation.
  • the frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • u is the root number of the ZC sequence
  • x u (i) represents a piece of data in the original ZC sequence
  • N zc is the length of the ZC sequence
  • x u,v (n) represents a piece of data in the ZC sequence that has undergone cyclic shift processing
  • C v is the cyclic shift.
  • c(n) is an element in the mask sequence, Represents a piece of data in the frequency domain sequence.
  • the expression form of the mask sequence may be a pseudo-random sequence, which may specifically include m-sequence, M-sequence, Gold sequence and other forms.
  • the user terminal randomly accesses the frequency domain data of the preamble sequence against frequency offset After mapping to the corresponding subcarrier of the random access time-frequency resource, the time-domain form of the anti-frequency offset random access preamble sequence is generated through IFFT, which is used as the uplink synchronization time-domain data sent by the terminal.
  • the sending process of the anti-frequency offset preamble sequence is shown in Fig. 3.
  • the base station receives the time-domain data of the anti-frequency offset random access preamble sequence, and uses the data to perform uplink timing and frequency offset estimation. After the base station estimates and compensates the fractional multiple normalized subcarrier frequency offset of the received data, it needs to complete the joint estimation of the uplink synchronization point and the integer multiple normalized subcarrier frequency offset. In order to reduce processing complexity, the base station needs to determine the integer multiple normalized frequency offset range when performing time-frequency joint estimation. For example, the maximum residual frequency offset possible for uplink synchronization is 3.5kHz, and the subcarrier spacing of the random access preamble sequence is 1.25kHz. Then the normalized frequency offset range used for detection is limited to the range of [-3,3].
  • the base station uses each integer frequency offset in the frequency offset range [-3,3] to perform integer multiple normalized frequency offset compensation on the time-domain data after the fractional multiple normalized frequency offset compensation.
  • a group of compensated data is transformed into the frequency domain, and N zc subcarriers corresponding to the random access preamble time-frequency resource are taken out, and then the ZC sequence frequency domain data can be recovered using the mask corresponding to each subcarrier aligned with the preamble time-frequency resource, Then perform frequency-domain correlation processing. If and only if the integer multiple normalized frequency offset compensation is correct, a unique correlation peak will appear in the corresponding power delay spectrum.
  • the base station can simultaneously obtain the timing point and the coarse frequency offset estimation value including the frequency offset of the normalized subcarrier of the decimal multiple and the integer multiple.
  • the receiving process of the anti-frequency offset preamble sequence is shown as an example in Figure 4-A.
  • the mask recovery method on the base station side can be shown as an example in Figure 4-B.
  • the mask recovery and local sequence processing window is the frequency domain resource of the random access preamble, and the window contains N zc preamble sequence subcarriers.
  • the local mask sequence c(n) of the base station is aligned with the N zc preamble subcarriers of the random access preamble frequency domain resource one by one, and the frequency domain data is restored according to the same masking method as the terminal.
  • the random access preamble sequence for example has a certain anti-frequency offset function, it can also be called an anti-frequency offset random access preamble sequence. That is, the anti-frequency offset random access preamble sequence and the random access preamble sequence can be mixed.
  • the following examples illustrate the detection performance of the preamble sequence and time-frequency joint estimation algorithm designed in this application.
  • the random access preamble specified in the LTE/NR protocol uses the traditional uplink synchronization algorithm in the case of no frequency offset, and the anti-frequency offset preamble sequence proposed in this application is 2.3 times the normalized subcarrier frequency offset.
  • Frequency joint estimation algorithm the detection performance under the AWGN channel is shown in Figure 4-C to Figure 4-G. Among them, the timing detection threshold is determined based on the false detection rate being less than 0.1%.
  • Figure 4-C shows an example of the detection performance of the LTE/NR protocol random access preamble sequence.
  • Figure 4-D to Figure 4-G Anti-frequency offset random access preamble detection performance.
  • the performance of the anti-frequency offset preamble detection algorithm is reduced by about 2dB compared with the traditional detection method, which is considered to be within the acceptable range.
  • the preamble detection algorithm has no frequency offset range limitation, and can additionally obtain coarse frequency offset estimation results.
  • the frequency-offset random access preamble proposed in this embodiment is generated by using a mask to scramble the frequency domain data of the ZC sequence.
  • the time-frequency joint estimation algorithm described in this embodiment when the integer normalized frequency offset is correctly restored, the correlation of the ZC sequence will not be affected; when the integer normalized frequency offset is not recovered , The correlation of the ZC sequence is destroyed, so when the anti-frequency offset preamble sequence and the time-frequency joint estimation algorithm are used, the influence of the integer multiple normalized carrier frequency offset on the uplink synchronization can be eliminated.
  • the algorithm not only does not limit the frequency offset range, but also obtains uplink timing and frequency offset estimates at the same time, but the processing complexity of the base station side increases with the increase of the frequency offset range
  • the base station can also distinguish between using the same random access time-frequency resource and the same ZC sequence to send preamble sequences with different integer multiples of normalized frequency offset. Users.
  • the following example shows the mask generation method of the anti-frequency offset preamble sequence.
  • the terminal side When the terminal side generates the random access preamble sequence, it adds a mask to the frequency domain data generated by the ZC sequence.
  • the purpose is to destroy the correlation of the ZC sequence when the received sequence subcarrier of the base station is not aligned with the local sequence subcarrier. A false peak appears in the uplink synchronization detection, which affects the determination of the uplink timing position.
  • the mask sequence can choose to use commonly used pseudo-random sequence forms such as m-sequence, M-sequence, and Gold sequence.
  • the elements in the mask sequence are 1, -1 or a scaling value of 1, -1.
  • the mask sequence can be a mask sequence common to the entire network.
  • This sequence is the mask sequence of the random access preamble agreed by all base stations and terminals.
  • all base stations and terminals use a mask sequence containing the same elements;
  • the code sequence may be a sequence common to a cell (or satellite beam), where the generation of the sequence is related to at least one cell (or satellite beam) specific parameter, and the cell (or satellite beam) specific parameter may, for example, apply for one of the following parameters One or more types: cell (or satellite beam) index number, data subcarrier width index number, bandwidth part (BWP, Bandwidth Part) index number and synchronization signal block (Synchronization Signal Block, SSB) index number, etc.; the mask sequence is also It may be a sequence related to the random access time-frequency resource.
  • the generation of the sequence is related to at least one random access time-frequency resource related parameter.
  • the random access time-frequency resource parameter includes the start symbol and the start time of the time-frequency resource. Slot number, frequency
  • the frequency domain data and the mask are multiplied to change the phase of the frequency domain data.
  • the frequency domain data of the ZC sequence and the mask can be multiplied in many forms: for example, the real part and the imaginary part of the frequency domain data of the ZC sequence can be the same as the two different elements of the mask sequence c(2n) and c(2n+1). Multiply, or 1 ZC sequence frequency domain data as a whole multiplied by an element c(n) of the mask sequence, or N frequency domain data of the ZC sequence as a whole multiplied by an element c(n) of the mask sequence .
  • the masking of the frequency domain data on the terminal side is consistent with the unmasking of the frequency domain data on the base station side.
  • the form of masking at the transceiver end can be an agreement between the terminal and the base station, or the form indicated by the base station.
  • the base station needs to transmit the masking form to the terminal through at least one of the broadcast information of SIB1, OSI, MIB, etc. Instructions.
  • the base station can use an index number in the index table of indication forms as shown in Figure 4-H to indicate the masking form to the terminal.
  • the index table is agreed upon by the terminal and the base station, or the base station sends out the broadcast information.
  • the residual frequency offset is small
  • the residual Doppler frequency offset of a cell with a small elevation angle (or satellite beam) is small, or the base station serves a terminal that uses a high-precision crystal oscillator.
  • the mask function of the random access preamble that is, the random access preamble uses the same generation process as the existing protocol, or the elements in the mask sequence are considered to be all 1 or a scaled value of 1.
  • the cell (or satellite beam) or service terminal increase the configuration function of whether to use the random access preamble mask: the cell (or satellite beam) level indicator parameters can be divided, and the mask is not enabled when the parameters are in a certain interval.
  • the method of parameter division is agreed between the base station and the terminal, or is issued by the base station in the broadcast information, where the indicator parameters include the Doppler frequency offset, the public round-trip transmission delay, and the public round-trip transmission delay change
  • the indicator parameters include the Doppler frequency offset, the public round-trip transmission delay, and the public round-trip transmission delay change
  • These indicating parameters are the corresponding parameters of a certain reference point in the cell (or satellite beam), or the corresponding parameter of a certain reference point plus an offset value; or at least one of the parameters in the broadcast information.
  • An indication mark for enabling the mask is added to the RRC information, MAC element or DCI, for example, a signaling whether to enable the mask is added to the RRC RACH configuration signaling.
  • x 1 (n+31) (x 1 (n+3)+x 1 (n))mod 2
  • x 2 (n+31) (x 2 (n+3)+x 2 (n+2)+x 2 (n+1)+x 2 (n))mod 2
  • the seeds are:
  • the mask sequence is a sequence related to the random access preamble time-frequency resource parameter.
  • the seed of the m-sequence constituting the mask sequence is obtained from multiple time-frequency resource parameters according to certain operation rules, and the parameters related to the seed include the starting symbol s_id of the time-frequency resource, the starting time slot number t_id, and the frequency domain resource. Number f_id and uplink carrier number ul_carrier_id and so on.
  • the m-sequence seed generation method is:
  • the mask sequence c(n) is generated using the above-mentioned seed and Gold sequence generation rules.
  • the terminal side and the base station side agree to multiply one ZC sequence frequency domain data as a whole by an element c(n) of the mask sequence, and the length of the generated mask sequence is at least N zc .
  • the frequency domain data of the ZC sequence is masked, it is mapped to the corresponding subcarrier of the random access time-frequency resource, and the terminal side generates the final random access time domain data through IFFT.
  • the above examples exemplify the specific expression form and generation method of the mask sequence of the anti-frequency offset access preamble.
  • the mask sequence can use different forms of pseudo-random sequences, the sequence generation may be related to different parameters, and the frequency domain data of the ZC sequence may also have different masking methods. Add a mask to the frequency domain data generated by the original ZC sequence, so that when the received sequence subcarriers of the base station are not aligned with the local sequence subcarriers, the correlation of the ZC sequence is destroyed to avoid false correlation peaks during uplink synchronization, thereby affecting Determination of the uplink timing position.
  • the following example shows the design method of the basic format of the anti-frequency offset preamble sequence.
  • the random access preamble sent by the terminal will be simultaneously affected by a large residual frequency offset and round-trip transmission delay (difference).
  • the anti-frequency offset preamble sequence generated in the manner described in the foregoing embodiment has the ability to resist residual frequency offset.
  • the corresponding preamble sequence format needs to be designed. When the preamble sequence is affected by a large transmission delay, the base station can still use This sequence obtains the correct upstream timing position.
  • the terminal can still use the preamble sequence format specified by the existing protocol, and only needs to fill the anti-frequency offset preamble symbols generated in the manner described in the foregoing embodiment in the corresponding sequence format.
  • the round-trip transmission delay (difference) usually exceeds the cycle of the preamble format specified by the existing protocol Prefix length, so the terminal needs to use a new preamble sequence format and use a new preamble sequence padding method.
  • the design of a preamble sequence format is based on the basic time domain format of the random access preamble sequence as shown in FIG. 5-A, for example.
  • the random access preamble format should include three parts: a cyclic prefix, a sequence part, and a guard interval.
  • the length of the cyclic prefix part is Natural number Represents an integer number of leading symbols, Represents the leading sign of decimals, the range is T sym is the length of a leading symbol
  • the length of the sequence part T SEQ N SEQ T sym
  • N SEQ is a positive integer
  • the length of the guard interval part is T GT .
  • the length of the cyclic prefix and the guard interval may be greater than or less than the length of a preamble symbol T sym .
  • Figures 5-B to Figure 5-F illustrate several preamble formats.
  • the sequence part includes at least one subsequence A, and in addition, the sequence part may also include at least one subsequence B.
  • the subsequence A includes at least one preamble symbol, wherein the subsequence B includes at least one preamble symbol, and the preamble symbol included in the subsequence A is different from the preamble symbol included in the subsequence B; the subsequence A
  • the frequency domain sequence Za is obtained through frequency domain resource mapping and time-frequency transformation, and the frequency domain sequence Za is obtained based on the ZC sequence and the mask sequence.
  • the interval between any two subsequences B is at least greater than or equal to Indicates rounding up, where, Indicates the integer number of leading symbols contained in the cyclic prefix, Represents the decimal leading symbols contained in the cyclic prefix.
  • each subsequence A and each subsequence B are respectively greater than or equal to the length of the cyclic prefix.
  • the number of cyclic prefixes included in the random access preamble sequence is one
  • the subsequence A and the subsequence B are located between the cyclic prefix and the guard interval, or the time domain superimposed sequence of the subsequence A and the subsequence B is located between the cyclic prefix and the guard interval.
  • the random access preamble sequence includes a first cyclic prefix and a second cyclic prefix
  • At least one of the subsequences A is located between the first cyclic prefix and the second cyclic prefix, and at least one of the subsequences B is located between the second cyclic prefix and the guard interval;
  • At least one of the subsequences B is located between the first cyclic prefix and the second cyclic prefix, and at least one of the subsequences A is located between the second cyclic prefix and the guard interval;
  • the first cyclic prefix and the second cyclic prefix include at least one of the subsequence A and at least one of the subsequence B that alternately appear.
  • the base station When the length of the cyclic prefix is greater than one preamble symbol, the base station cannot use a sequence filled with only one preamble symbol to complete the uplink timing. At this time, at least two different preamble symbols need to be filled in the sequence. Therefore, a new sequence format and Leading symbol filling method.
  • the preamble format needs to be filled with two different preamble symbols ⁇ and ⁇ .
  • the anti-frequency offset preamble symbol is recorded as ⁇ , and the other preamble symbol is ⁇ .
  • the design is shown in Figure 5-B to Figure 5-E as examples.
  • the format of the preamble sequence is designed.
  • the subsequence A contains at least one preamble symbol placed consecutively, and the subsequence A contains at least one preamble symbol placed consecutively, wherein the subsequence A or the subsequence One of B is filled with anti-frequency offset preamble symbol ⁇ , and the other area is filled with preamble symbol ⁇ .
  • the area filled with the anti-frequency offset preamble symbol ⁇ includes at least two consecutive preamble symbols.
  • the format of the preamble sequence is designed in Figure 5-B. As shown in the figure, subsequence A and subsequence B are alternately placed. Each subsequence A contains at least one preamble symbol placed consecutively, and each subsequence B contains at least one consecutively placed preamble symbol. A leading symbol, the number of leading symbols contained in each area can be the same or different. One of the subsequence A or the subsequence B is filled with the anti-frequency offset preamble symbol ⁇ , and the other area is filled with the preamble symbol ⁇ .
  • At least one area filled with anti-frequency offset preamble symbol ⁇ contains at least two consecutive preamble symbols; when all subsequences A have the same length and all subsequences B have the same length, then all padding anti-frequency offset preambles
  • the region of symbol ⁇ contains at least two consecutive leading symbols, and the interval between adjacent regions filled with leading symbol ⁇ is at least greater than or equal to Indicates rounding up, that is, the difference between the index numbers of the starting preamble symbols of two adjacent areas filled with preamble symbols ⁇ is greater than or equal to
  • subsequence B is filled with anti-frequency offset preamble ⁇ , it is also required that the difference between the starting preamble symbol index numbers of all adjacent A regions is at least greater than or equal vice versa.
  • the other preamble symbol ⁇ can be generated in the same way as the anti-frequency offset preamble symbol ⁇ , but at least one of the ZC sequence root sequence number or the mask sequence of the preamble symbol ⁇ is different from the preamble symbol ⁇ , that is, the preamble symbol ⁇ and the preamble symbol ⁇ can use the same ZC sequence, different mask sequences, or use different ZC sequences, the same mask sequence, or use different ZC sequences, different mask sequences; the preamble symbol ⁇ can also use non-frequency offset resistance
  • the leading form such as directly filling with ZC sequence, filling with pseudo-random number, or directly setting this segment of symbols to all zeros.
  • a specific random access preamble format is given as an example. As shown in Fig. 5-F, it is a preamble sequence format that can resist the influence of large round-trip transmission delay (poor).
  • the preamble sequence is generated by a ZC sequence with a length of 839
  • the subcarrier width of the preamble sequence is 1.25 kHz
  • the length of a preamble symbol is 0.8 ms.
  • the cyclic prefix length of the preamble sequence format shown in Figure 5-F is 2.284ms, which is equivalent to 2.855 preamble symbols, that is, the cyclic prefix length of this format is based on the cyclic prefix of preamble format 1 specified by the NR protocol of 0.684ms.
  • each area filled with preamble symbol ⁇ contains two consecutive preamble symbols, and the difference between the start preamble symbol index numbers of two adjacent areas filled with preamble symbol ⁇ is 3, which is greater than or equal to Requirements.
  • the preamble ⁇ filled in the preamble sequence format can be generated by the ZC sequence with the root sequence number u and the mask sequence c 1 (n), and the preamble symbol ⁇ is generated by the ZC sequence with the root sequence number u and the mask sequence c 2 ( n) Generated, the leading symbols ⁇ and ⁇ are different symbols from each other.
  • the above example provides a preamble sequence format design scheme that is suitable for scenarios with large round-trip transmission delay (poor).
  • the base station can detect the uplink timing position of the terminal sending the preamble sequence of the format to meet the requirements of the satellite communication system.
  • a satellite communication method may include:
  • a random access preamble sequence wherein the random access preamble sequence includes a cyclic prefix, a sequence part, and a guard interval, and the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation.
  • the frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • the frequency offset estimation indication is carried in the frequency offset estimation value feedback field of the medium access control random access response MAC RAR; or, the frequency offset estimation indication is carried in the random access wireless network temporary identifier RA-RNTI.
  • the following examples provide some feedback forms of the uplink residual frequency offset estimation value.
  • the base station side should feed back to the terminal the residual frequency offset estimation value obtained through the uplink initial synchronization, so that the terminal can adjust the frequency offset compensation value to eliminate the residual frequency offset of the subsequent uplink signal.
  • the base station should feed back the frequency offset estimation value to the terminal in the RAR.
  • the first way to indicate the estimated value of the residual frequency offset is to add a field indicating the estimated value of the frequency offset to the RAR.
  • Figure 6-B shows a way to add fields.
  • MAC RAR increase the length of the 8-bit frequency offset estimation value feedback field, and the fields added on the way are expressed in bold font.
  • the frequency offset value indicated in the RAR window can be expressed as an absolute frequency offset value representing the true frequency offset value, or it can be a normalized subcarrier frequency proportional to the random access preamble subcarrier or the uplink data subcarrier.
  • Bias. RAR can directly indicate the frequency offset value, or indicate the scaling value of the frequency offset value, or it can indicate an index number corresponding to the frequency offset value, where the mapping relationship between the index number and the frequency offset value is agreed upon by the base station and the terminal , Or determined by the frequency offset value index table issued by the base station.
  • the second indication method of the residual frequency offset may be to reduce the field occupation in the RAR as much as possible, and to add an implicit frequency offset indication in the RA-RNTI.
  • a form of adding implicit frequency offset indication in RA-RNTI For example, a form of adding implicit frequency offset indication in RA-RNTI:
  • RA_RNTI 1+s_id+14 ⁇ t_id+14 ⁇ 80 ⁇ f_id+14 ⁇ 80 ⁇ 8 ⁇ ul_carrier_id+ 14 ⁇ 80 ⁇ 8 ⁇ 2 ⁇ fre_est_id
  • the non-underlined part is the RA_RNTI calculation part stipulated by the NR protocol, and the underlined part is the added implicit frequency offset indication part.
  • the NR protocol stipulates that the value range of RA-RNTI is 0x0001 ⁇ 0xFFEF, the value of fre_est_id is 0,1,2. Since the value of fre_est_id is small, it may only include part of the feedback frequency offset.
  • the frequency offset of the carrier; or as an indication of the frequency offset of several integer multiples of normalized subcarriers, for example, fre_est_id 0,1,2 respectively represent the frequency offsets of -4, 0, 4 integer multiples of normalized preamble sequence subcarriers .
  • the mapping relationship between fre_est_id and the frequency offset value may be agreed between the base station and the terminal, or may be indicated by the base station through at least one of broadcast information such as SIB1, OSI, and MIB. Wherein, when the indication range of the parameter fre_est_id is insufficient, fre_est_id and the field added by the RAR can be used to jointly indicate the feedback frequency offset estimation value.
  • the terminal side needs to traverse all possible values of fre_est_id when monitoring the RAR to descramble the PDCCH and obtain the downlink control information contained therein.
  • the base station side can use the frequency offset tracking function to feed back the frequency offset tracking or its related parameters to the terminal so that the terminal can eliminate the residual frequency offset of the subsequent uplink signal.
  • the base station can choose to feed back the residual frequency offset estimated value obtained through tracking to the terminal.
  • the indication position of the frequency offset estimated value can be user-level RRC information, MAC element (for example, placed in the MAC element of the transmission timing advance update command) or DCI.
  • the indication form of the estimated deviation value can be an absolute frequency deviation value, a normalized frequency deviation value, a scaling value of an absolute or normalized frequency deviation value, or an index number of an absolute or normalized frequency deviation value,
  • the mapping relationship between the index number and the frequency offset value may be agreed upon by the base station and the terminal, or issued by the base station through at least one of broadcast information such as SIB and MIB.
  • the base station can also indicate the rate of change of the residual frequency offset to the terminal.
  • this parameter can be used as a cell (or satellite beam) level parameter in at least one of the broadcast information such as SIB and MIB.
  • the terminal indicates that the indication form of the frequency offset change rate can be the absolute frequency offset change rate, the normalized frequency offset change rate, the scaling value of the absolute or normalized frequency offset change rate, or the absolute or normalized frequency offset change rate.
  • the index number of the index number, where the mapping relationship between the index number and the frequency offset change rate may be agreed upon by the base station and the terminal, or may be issued by the base station through at least one of the broadcast information.
  • the base station side can also use an extra bit to indicate the source of the frequency offset, so that the sender and receiver can perform corresponding processing and indicate
  • the location may be at least one of broadcast information, or RRC information, MAC element, or DCI.
  • the above examples provide some residual frequency offset feedback methods, using fields in RAR to directly or indirectly feed back the frequency offset estimation value, or adding implicit frequency offset indication information in RA-RNTI to indicate all or Part of the frequency offset information.
  • the above example scheme considers to minimize the overhead of frequency offset feedback, and at the same time, the feedback mode needs to have a certain degree of flexibility.
  • the anti-frequency offset preamble sequence exemplified in the embodiment of the present application can eliminate the influence of a larger normalized subcarrier frequency offset during uplink synchronization, and retain the relevant characteristics of the ZC sequence.
  • the uplink synchronization algorithm of the embodiment of the present application does not limit the frequency offset range, and can obtain timing and frequency offset estimation values at the same time.
  • the residual frequency offset feedback in the embodiment of the present application may have a variety of different indication methods, which improves the flexibility of the residual frequency offset feedback.
  • the following also provides related equipment for implementing the above scheme.
  • an embodiment of the present application provides a satellite communication device 700, including:
  • the sending unit 710 is configured to generate a random access preamble sequence, the random access preamble sequence includes a cyclic prefix, a sequence part and a guard interval, and the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation, The frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • the output unit 720 outputs the random access preamble sequence.
  • an embodiment of the present application provides a satellite communication device 800, including:
  • the communication unit 810 is configured to receive a random access preamble sequence; the random access preamble sequence includes a cyclic prefix, a sequence part and a guard interval, and the sequence part is obtained from a frequency domain sequence through frequency domain resource mapping and time-frequency transformation, The frequency domain sequence is obtained based on the ZC sequence and the mask sequence.
  • the detecting unit 820 is configured to perform uplink time-frequency estimation based on the received random access preamble sequence to obtain a frequency offset estimation value Consists of frequency deviation caused by crystal error and/or Doppler frequency deviation.
  • the communication unit 810 is further configured to send a frequency offset estimation indication to the terminal, where the frequency offset estimation indication is used to indicate the frequency offset estimation value
  • the frequency offset estimation indication is carried in the frequency offset estimation value feedback field of the medium access control random access response MAC RAR; or, the frequency offset estimation indication is carried in the random access wireless network temporary identifier RA-RNTI.
  • an embodiment of the present application also provides a satellite communication device 900 (satellite communication device 900 such as a terminal device or a ground base station or satellite, etc.), which may include a processor 910 and a memory 920 coupled to each other.
  • the processor is configured to call a computer program stored in the memory to execute part or all of the steps of any method provided in the embodiments of the present application.
  • the embodiments of the present application also provide a computer-readable storage medium, the computer-readable storage medium stores a computer program, wherein the computer program is executed by a processor to complete any of the methods provided in the embodiments of the present application Part or all of the steps.
  • the embodiments of the present application also provide a computer program product including instructions.
  • the satellite communication device can execute part or all of the steps of any method provided in the embodiments of the present application. .
  • an embodiment of the present application further provides a communication device 1000, including: an input interface circuit 1001, a logic circuit 1002, and an output interface circuit 1003; wherein the logic circuit is used to execute any one of the embodiments provided in this application Part or all of the steps of the method.
  • an embodiment of the present application further provides a communication device 1100, including at least one input terminal 1101, a signal processor 1101, and at least one output terminal 1103; wherein, the signal processor 1102 is configured to execute the embodiment of the present application Part or all of the steps of any one of the methods provided.
  • the embodiment of the present application also provides a computer-readable storage medium, and the computer-readable storage medium stores a computer program, and the computer program is executed by hardware (such as a processor, etc.) to implement any device in the embodiment of the present application. Part or all of the steps of any method performed.
  • the embodiments of the present application also provide a computer program product including instructions, which when the computer program product runs on a computer device, cause the computer device to execute part or all of the steps of any one of the above aspects.
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center integrated with one or more available media.
  • the usable medium may be a magnetic medium (such as a floppy disk, a hard disk, and a magnetic tape), an optical medium (such as an optical disk), or a semiconductor medium (such as a solid-state hard disk).
  • the disclosed device may also be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or integrated. To another system, or some features can be ignored or not implemented.
  • the displayed or discussed indirect coupling or direct coupling or communication connection between each other may be through some interfaces, indirect coupling or communication connection between devices or units, and may be in electrical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. . Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • the functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit may be implemented in the form of hardware, or may also be implemented in the form of software functional unit.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of the application essentially or the part that 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.
  • a number of instructions are included to enable a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage medium may include, for example, U disk, mobile hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disks or optical disks, and other storable program codes. Medium.

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Abstract

卫星通信方法和相关设备。一种卫星通信方法包括：生成随机接入前导序列，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到；输出所述随机接入前导序列。本申请实施例中提出的具有抗频偏能力的随机接入前导利用掩码加扰ZC序列的频域数据生成，测试发现它使得序列具有较好的抗频偏能力。

Description

卫星通信方法和相关通信设备
本申请要求于2019年09月30日提交中国专利局、申请号为201910944848.2、申请名称为“卫星通信方法和相关通信设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及卫星通信方法和相关通信设备。
背景技术
卫星通信具有全球覆盖、远距离传输、组网灵活、部署方便和不受地理条件限制等显著优点，故而已经被广泛应用于海上通信、定位导航、抗险救灾、科学实验、视频广播和对地观测等多个领域。
未来地面第五代移动网络(5G)将具备完善的产业链、巨大的用户群体、灵活高效的应用服务模式等。因此，将卫星通信系统与5G网络相互融合，取长补短，共同构成全球无缝覆盖的海、陆、空、天一体化综合通信网，满足用户无处不在的多种业务需求，是未来通信发展的一个重要方向。
卫星通信系统使用非静止轨道(NGEO,Non-Geostationary Earth Orbit)卫星。根据卫星的轨道高度，具体可以将卫星移动通信系统分为同步轨道(GEO,Geostationary Earth Orbit)系统、中轨(MEO,Medium Earth Orbit)卫星通信系统和低轨(LEO,Low Earth Orbit)卫星通信系统。
无论是地面蜂窝移动通信系统还是卫星移动通信系统，载波频偏都会极大地恶化通信系统的工作性能。载波频偏的主要来源为：通信系统收发两端所采用的晶体振荡器的频率误差和无线信道的多普勒频偏。
其中，对于地面移动通信系统，载波频偏主要源自晶振误差，在高铁、飞机等高速移动通信场景中，多普勒频偏也是载波频偏的重要组成部分。对于卫星移动通信系统，尤其是低轨卫星移动通信系统，除了晶振误差引起的载波频偏，星地链路中还普遍存在较大的多普勒频偏。
然而，当然业内还没有设计出较为成熟可靠的可用于较好解决卫星移动通信系统中的载波频偏的相关方案。
发明内容
本申请实施例提供卫星通信方法和相关通信设备。
第一方面，本申请实施例提供提供一种卫星通信方法，包括：
生成随机接入前导序列，其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于 ZC序列和掩码序列得到；输出所述随机接入前导序列。
例如，
x u,v(n)＝x u((n+C v)modN zc)
Figure PCTCN2020119184-appb-000001
其中，u为ZC序列的根序号，x u(i)表示原始的ZC序列中的一个数据，
其中，N zc为ZC序列长度，x u,v(n)表示经过循环移位处理的ZC序列中的一个数据，C v为循环移位；
其中，
Figure PCTCN2020119184-appb-000002
Figure PCTCN2020119184-appb-000003
其中，c(n)为掩码序列中的一个元素，
Figure PCTCN2020119184-appb-000004
表示频域序列中的一个数据。
举例来说，所述掩码序列为m序列、M序列或Gold序列，其中，所述掩码序列中的元素为1、-1或1、-1的缩放值。
举例来说，所述掩码序列为全网通用的掩码序列，所述掩码序列为所有基站与终端约定的随机接入前导的掩码序列，所有基站和终端使用包含相同元素的掩码序列。
或者，所述掩码序列是一个小区或卫星波束通用的掩码序列，所述掩码序列的生成与至少一个小区或卫星波束特定参数相关，其中，所述小区或卫星波束特定参数包括如下参数中的一种或者多种：小区或卫星波束索引号、数据子载波宽度索引号、同步信号块索引号或带宽部分索引号；
或者，
所述掩码序列是与随机接入时频资源相关的序列，所述掩码序列的生成与至少一个随机接入时频资源相关参数相关，其中，所述随机接入时频资源参数包括如下参数中的一种或者多种：时频资源的起始符号、起始时隙号、频域资源号或上行载波号。
举例来说，所述序列部分包括至少一个子序列A，此外，所述序列部分还可包括至少一个子序列B。所述子序列A包含至少一个前导符号，其中，所述子序列B包含至少一个前导符号，所述子序列A包含的前导符号不同于所述子序列B包含的前导符号；所述子序列A由频域序列Za经频域资源映射和时频变换而得到，所述频域序列Za基于ZC序列和掩码序列得到。
举例来说，在所有子序列A的长度相等，所有子序列B的长度相等的情况下，任意两个子序列B相邻的间隔至少大于或等于
Figure PCTCN2020119184-appb-000005
表示向上取整，其中，
Figure PCTCN2020119184-appb-000006
表示循 环前缀包含的整数个前导符号，
Figure PCTCN2020119184-appb-000007
表示循环前缀包含的小数个前导符号。
举例来说，每个所述子序列A和每个所述子序列B的长度分别都大于或等于所述循环前缀的长度。
举例来说，所述随机接入前导序列包括的循环前缀的数量为一个，
其中，所述子序列A和子序列B位于所述循环前缀和所述保护间隔之间，或者所述子序列A和子序列B的时域叠加序列位于所述循环前缀和所述保护间隔之间。
举例来说，所述随机接入前导序列包括第一循环前缀和第二循环前缀；
其中，至少一个所述子序列A位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列B位于所述第二循环前缀和所述保护间隔之间；
或者，
至少一个所述子序列B位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列A位于所述第二循环前缀和所述保护间隔之间；
或者，
其中，所述第一循环前缀和所述第二循环前缀之间包括交替出现的至少一个所述子序列A和至少一个所述子序列B。
第二方面，本申请实施例提供一种卫星通信设备，包括：
发送单元，用于生成随机接入前导序列，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
输出单元，输出所述随机接入前导序列。
第三方面，本申请实施例提供一种卫星通信方法，包括：
接收随机接入前导序列；所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
基于接收到的所述随机接入前导序列进行上行时频估计以得到频偏估计值为
Figure PCTCN2020119184-appb-000008
由晶振误差和/或多普勒频偏引起的频偏构成。向终端发送频偏估计指示，其中，所述频偏估计指示用于指示出所述频偏估计值
Figure PCTCN2020119184-appb-000009
例如所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
第四方面，本申请实施例提供一种卫星通信设备，包括：
通信单元，用于接收随机接入前导序列；所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
检测单元，用于基于接收到的所述随机接入前导序列进行上行时频估计以得到频偏估计值为
Figure PCTCN2020119184-appb-000010
由晶振误差和/或多普勒频偏引起的频偏构成。
通信单元还用于，向终端发送频偏估计指示，其中，所述频偏估计指示用于指示出所述频偏估计值
Figure PCTCN2020119184-appb-000011
例如所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反 馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
第五方面，本申请实施例还提供一种卫星通信设备，包括：相互耦合的处理器和存储器；
其中，所述处理器用于调用所述存储器中存储的计算机程序，以执行第一方面或第三方面的任意一种方法的部分或全部步骤。
第六方面，本申请实施例还提供一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，其中，所述计算机程序被处理器执行，以完成以上各方面的方法的部分或全部步骤。
第七方面，本申请实施例还提供了一种包括指令的计算机程序产品，当所述计算机程序产品在用户设备上运行时，使得卫星通信设备执行以上各方面的方法的部分或全部步骤。
第八方面，本申请实施例还提供一种通信装置，包括：至少一个输入端、信号处理器和至少一个输出端；其中，所述信号处理器，用于执行以上各方面的任意一种方法的部分或全部步骤。
第九方面，本申请实施例还提供一种通信装置，包括：输入接口电路，逻辑电路和输出接口电路；其中，所述逻辑电路用于执行以上各方面的任意一种方法的部分或全部步骤。
附图说明
下面将对本申请实施例涉及的一些附图进行说明。
图1-A是本申请实施例提供的一种通信系统的架构示意图。
图1-B是本申请实施例提供的卫星通信的场景示意图。
图2是本申请实施例提供的一种卫星通信方法的流程示意图。
图3是本申请实施例提供的随机接入前导序列的发送机制示意图。
图4-A至图4-B是本申请实施例提供的掩码恢复方法的示意图。
图4-C至图4-F是本申请实施例提供的随机接入前导序列的检测性能的几种示意图。
图4-G是本申请实施例提供的指示映射表的意图。
图4-H是本申请实施例提供的指示形式索引表的意图。
图5-A至图5-F是本申请实施例提供的随机接入前导序列的格式示意图。
图6-A是本申请实施例提供的另一种卫星通信方法的流程示意图。
图6-B是本申请实施例提供的一种消息格式的示意图。
图7是本申请实施例提供的一种卫星通信设备的结构示意图。
图8是本申请实施例提供的另一种卫星通信设备的结构示意图。
图9是本申请实施例提供的另一种卫星通信设备的结构示意图。
图10是本申请实施例提供的另一种卫星通信设备的结构示意图。
图11是本申请实施例提供的另一种卫星通信设备的结构示意图。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。
参见图1-A，图1-A是本申请实施例举例的一种5G网络架构的示意图。5G网络对4G 网络的某些功能网元(例如移动性管理实体(MME，Mobility Management Entity)等等)进行了一定拆分，并定义了基于服务化架构的架构。在图1-A所示网络架构中，类似4G网络中的MME的功能，被拆分成了接入与移动性管理功能(AMF,Access and Mobility Management Function)和会话管理功能(SMF,Session Management Function)等等。
下面对其他一些相关网元/实体进行介绍。
用户终端(UE，User Equipment)通过接入运营商网络来访问数据网络(DN，Data Network)等等，使用DN上的由运营商或第三方提供的业务。
为方便说明，本申请实施例中用户终端、用户设备、终端设备或终端可统称为UE。即若无特别说明，本申请实施例后文所描述的UE均可替换为用户终端、用户设备、终端设备或者终端，当然它们之间也可互换。
接入与移动性管理功能(AMF)是3GPP网络中的一种控制面功能，主要负责UE接入运营商网络的接入控制和移动性管理。其中，安全锚点功能(SEAF,Security Anchor Function)可以部署于AMF之中，或SEAF也可能部署于不同于AMF的另一设备中，图1-A中以SEAF被部署于AMF中为例。当SEAF被部署于AMF中时，SEAF和AMF可合称AMF。
会话管理功能(SMF)是3GPP网络中的一种控制面功能，其中，SMF主要用于负责管理UE的数据包(PDU,Packet Data Unit)会话。PDU会话是一个用于传输PDU的通道，UE可以通过PDU会话与DN互相发送PDU。SMF负责PDU会话的建立、维护和删除等管理工作。
数据网络(DN,Data Network)也称为分组数据网络(PDN,Packet Data Network)，是位于3GPP网络之外的网络。其中，3GPP网络可接入多个DN，DN上可部署运营商或第三方提供的多种业务。例如，某个DN是一个智能工厂的私有网络，安装在智能工厂车间的传感器扮演UE的角色，DN中部署了传感器的控制服务器。UE与控制服务器通信，UE在获取控制服务器的指令之后，可根据这个指令将采集的数据传递给控制服务器。又例如，DN是一个公司的内部办公网络，该公司员工所使用的终端则可扮演UE的角色，这个UE可以访问公司内部的信息和其他资源。
其中，统一数据管理实体(UDM，Unified Data Management)也是3GPP网络中的一种控制面功能，UDM主要负责存储3GPP网络中签约用户(UE)的签约数据、信任状(credential)和持久身份标识(SUPI,Subscriber Permanent Identifier)等。这些数据可以被用于UE接入运营商3GPP网络的认证和授权。
认证服务器功能(AUSF,Authentication Server Function)也是3GPP网络中的一种控制面功能，AUSF主要用于第一级认证(即3GPP网络对其签约用户的认证)。
其中，网络开放功能(NEF,Network Exposure Function)也是3GPP网络之中的一种控制面功能。NEF主要负责以安全的方式对第三方开放3GPP网络的对外接口。其中，在SMF等功能需要与第三方网元通信时，可以以NEF为通信的中继。其中，中继时，NEF可以进行内外部标识的翻译。比如将UE的SUPI从3GPP网络发送到第三方时，NEF可将SUPI翻译成其对应的外部身份标识(ID,Identity)。反之，NEF可将外部身份ID在发送到3GPP网络时，将其翻译成对应的SUPI。
其中，网络存储功能(NRF,Network Repository Function)也是3GPP网络中的一种控制面 功能，主要负责存储可被访问的网络功能(NF)的配置额服务资料(profile)，为其他网元提供网络功能的发现服务。
用户面功能(UPF,User Plane Function)是3GPP网络与DN通信的网关。
策略控制功能(PCF,Policy Control Function)是3GPP网络中的一种控制面功能，用于向SMF提供PDU会话的策略。策略可包括计费、服务质量(QoS,Quality of Service)、授权相关策略等。
接入网(AN，Access Network)是3GPP网络的一个子网络，UE要接入3GPP网络，首先需要经过AN。在无线接入场景下AN也称无线接入网(RAN,Radio Access Network),因此RAN和AN这两个术语经常不做区分的混用。
3GPP网络是指符合3GPP标准的网络。其中，图1-A中除了UE和DN以外的部分可看作是3GPP网络。3GPP网络不只局限于3GPP定义的5G网络，还可包括2G、3G、4G网络。通常3GPP网络由运营商来运营。此外，在图1-A所示架构中的N1、N2、N3、N4、N6等分别代表相关实体/网络功能之间的参照点(Reference Point)。Nausf、Namf...等分别代表相关网络功能的服务化接口。
当然，3GPP网络和非3GPP网络可能共存，5G网络的中的一些网元也可能被运用到一些非5G网络中。
未来地面5G将具备完善产业链、巨大用户群体、灵活高效的应用服务模式等。因此将卫星通信系统与5G网络相互融合，取长补短，共同构成全球无缝覆盖的海、陆、空、天一体化综合通信网，满足用户无处不在的多种业务需求，是未来通信发展的一个重要方向。
参见图1-B，图1-B举例示出卫星通信的场景示意图。卫星具备信号处理能力或者卫星将用户信号透明转发到地面基站实现广域覆盖的通信场景，可以采用与3GPP LTE/NR协议兼容的协议栈。用户终端为普通的移动终端或专用终端，传输过程也遵循LTE/NR协议。本申请讨论的方案也适用于3GPP LTE/NR定义的地面移动通信场景，且更适用于高铁、飞机等高速移动通信场景。
下面对卫星通信场景进行一些简单介绍。
对于非同步卫星移动通信系统，尤其是低轨卫星移动通信系统而言，卫星的运行速度相对较快，这使得信号在传输过程中产生大范围快速时变的多普勒频偏。研究发现，在卫星移动通信系统中，引起时频同步问题的主要因素是大多普勒频偏和晶振误差引起的频偏，而传统的时频估计算法在下行同步中仅能估计出两种频偏的叠加值，即f d+f e，其中f d表示多普勒频偏，f e表示晶振误差引起的频偏。其中，因为多普勒频偏和晶振误差引入的频偏的生成原理不同，合理的频偏补偿方式应当是终端侧对发送的上行信号补偿-f d+f e，即对多普勒频偏采用负补偿方式，对晶振误差引起的频偏采用正补偿方式。如果用户终端直接利用下行同步的频偏估计结果对上行发送信号进行频偏补偿，则会在上行信号中引入频率偏移2f e(负补偿)或2f d(正补偿)。
举例来说，设想一种卫星通信场景，低轨卫星通信系统的卫星轨道高度为600km，卫 星基站将波束中心处的多普勒频偏作为预补偿值，补偿下行数据的部分多普勒频偏。依据3GPP会议文稿提供的参数，这个系统中处于半径为200km的星下波束边缘的终端的残留多普勒频偏为4.14ppm，该终端晶振误差为5ppm，卫星基站的晶振误差忽略不计。用户终端获取频偏估计值后，若采用正补偿方式，最大上行残留频偏约为8.3ppm，即载波为2GHz时残留频偏为16.6kHz，载波为30GHz时残留频偏为249kHz；如果采用负补偿方式，最大上行残留频偏约为10ppm，即载波为2GHz时残留频偏为20kHz，载波为30GHz时残留频偏为300kHz。由此可见，卫星移动通信系统的上行残留频偏较地面通信系统大得多，而较大的残留频偏会对LTE/NR协议规定的随机接入前导序列造成严重影响，导致其上行同步性能下降，甚至使上行同步的功能完全失效。
本申请实施例提供的随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
参见图2，图2为本申请实施例举例的一种卫星通信方法的流程示意图。一种卫星通信方法可包括：
201.生成随机接入前导序列，其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
202.输出所述随机接入前导序列。
具体来说，
x u,v(n)＝x u((n+C v)modN zc)
Figure PCTCN2020119184-appb-000012
其中，u为ZC序列的根序号，x u(i)表示原始的ZC序列中的一个数据。
其中，N zc为ZC序列长度，x u,v(n)表示经过循环移位处理的ZC序列中的一个数据，C v为循环移位。
其中，
Figure PCTCN2020119184-appb-000013
Figure PCTCN2020119184-appb-000014
其中，c(n)为掩码序列中的一个元素，
Figure PCTCN2020119184-appb-000015
表示频域序列中的一个数据。
其中，掩码序列的表现形式可以为伪随机序列，具体可包括m序列，M序列，Gold序列等形式。
用户终端将抗频偏随机接入前导序列的频域数据
Figure PCTCN2020119184-appb-000016
映射到随机接入时频资源的对应子载波后，通过IFFT生成抗频偏随机接入前导序列的时域形式，将其作为终端发送的上行同步时域数据。抗频偏前导序列的发送流程具体如图3所示。
相应的，基站接收抗频偏随机接入前导序列的时域数据，并使用该数据进行上行定时与频偏估计。基站在估计和补偿接收数据的小数倍归一化子载波频偏后，需要完成上行同步点和整数倍归一化子载波频偏的联合估计。为了降低处理复杂度，基站进行时频联合估计时需要确定整数倍归一化频偏范围，例如上行同步可能的最大残留频偏为3.5kHz，随机接入前导序列的子载波间隔为1.25kHz，则检测使用的归一化频偏范围限制在[-3,3]范围内。基站使用频偏范围[-3,3]中的每一个整数倍频偏，对经小数倍归一化频偏补偿后的时域数据分别进行整数倍归一化频偏补偿，并将每一组补偿后的数据变换到频域，取出随机接入前导时频资源对应的N zc个子载波，进而可利用与前导时频资源对齐的每个子载波相应的掩码恢复ZC序列频域数据，再进行频域相关处理。当且仅当整数倍归一化频偏补偿正确时，对应的功率时延谱中会出现唯一的相关峰。由此，基站可以同时获得定时点和包含小数倍和整数倍归一化子载波频偏的粗频偏估计值。抗频偏前导序列的接收流程具体如图4-A举例所示。
基站侧掩码恢复方法可如图4-B举例所示。掩码恢复与本地序列处理窗口内即随机接入前导的频域资源，该窗口内含N zc个前导序列子载波。掩码恢复时，基站的本地掩码序列c(n)与随机接入前导频域资源的N zc个前导子载波一一对齐，按照与终端相同的加掩码方式恢复频域数据。
由于举例的随机接入前导序列具有一定的抗频偏功能，因此它也可称之为抗频偏随机接入前导序列。即抗频偏随机接入前导序列和随机接入前导序列可混用。
下面举例说明书本申请设计的前导序列和时频联合估计算法的检测性能。LTE/NR协议规定的随机接入前导序列在无频偏情况下，使用传统上行同步算法，与本申请提出的抗频偏前导序列在2.3倍归一化子载波频偏情况下，使用上述时频联合估计算法，在AWGN信道下的检测性能如图4-C至图4-G所示。其中，定时检测门限根据虚检率小于0.1％确定。图4-C举例示出了LTE/NR协议随机接入前导序列的检测性能。图4-D至图4-G抗频偏随机接入前导序列的检测性能。
其中，抗频偏前导检测算法相比于传统检测方法的性能下降约2dB，认为是在可接受范围内。另外，相比于传统检测算法，该前导检测算法无频偏范围限制，并且可以额外获取粗频偏估计结果。
可以看出，相比于现有LTE/NR协议规定的随机接入前导序列，本实施例中提出的抗频偏随机接入前导利用掩码加扰ZC序列的频域数据生成。利用本实施例所述的时频联合估计算法，在整数倍归一化频偏正确恢复的情况下，ZC序列的相关性不会受到影响；在整数倍归一化频偏没有恢复的情况下，ZC序列的相关性被破坏，因此使用抗频偏前导序列和时频联合估计算法时，能够排除整数倍归一化载波频偏对上行同步的影响。利用抗频偏前导序列和前述算法进行上行同步，算法不仅对频偏范围不作限制，还能同时获取上行定时和频偏估计值，但基站侧的处理复杂度随频偏范围增大有所上升；除此之外，使用本实施例中所述前导序列和算法时，基站还可以区分使用相同随机接入时频资源、相同ZC序列 发送存在不同整数倍归一化频偏的前导序列的多个用户。
下面举例展示了抗频偏前导序列的掩码生成方法。
终端侧生成随机接入前导序列时，在由ZC序列生成的频域数据上加掩码，目的是在基站的接收序列子载波与本地序列子载波未对齐时，破坏ZC序列的相关性，避免在上行同步检测中出现虚假峰值，影响上行定时位置的确定。
基于性能优化的考虑，需要选择具有较好的自相关性和互相关性的序列作为掩码序列。掩码序列可选择使用m序列、M序列、Gold序列等常用的伪随机序列形式。掩码序列中的元素为1、-1或者为1、-1的缩放值。
其中，掩码序列可为一个全网通用的掩码序列，该序列为所有基站与终端约定的随机接入前导的掩码序列，其中，所有基站和终端使用包含相同元素的掩码序列；掩码序列可以是一个小区(或者卫星波束)通用的序列，其中，该序列的生成与至少一个小区(或者卫星波束)特定参数相关，小区(或者卫星波束)特定参数例如可报考如下参数中的一种或多种：小区(或者卫星波束)索引号，数据子载波宽度索引号，带宽部分(BWP,Bandwidth Part)索引号和同步信号块(Synchronization Signal Block,SSB)索引号等；掩码序列也可以是一个与随机接入时频资源相关的序列，该序列的生成与至少一个随机接入时频资源相关参数相关，随机接入时频资源参数包括时频资源的起始符号、起始时隙号、频域资源号及上行载波号等等。
ZC序列频域数据加掩码时，将频域数据与掩码相乘，来改变频域数据相位。ZC序列频域数据与掩码相乘有多种形式：例如ZC序列频域数据的实部和虚部可以分别与掩码序列的c(2n)和c(2n+1)两个不同元素相乘，或者1个ZC序列频域数据作为整体与掩码序列的一个元素c(n)相乘，或者N个ZC序列的频域数据作为整体与掩码序列的一个元素c(n)相乘。
终端侧频域数据加掩码与基站侧频域数据解掩码的形式保持一致。收发端加掩码的形式可以是终端与基站的约定方式，也可为基站指示的方式，基站指示时需通过SIB1、OSI、MIB等的广播信息中的至少一种向终端传输加掩码形式的指示信息。基站可以使用一个如图表4-H所示的指示形式索引表中的索引号，向终端指示加掩码的形式，索引表是终端与基站约定的，或者是基站在广播信息中下发的。
其中，残留频偏较小的场景，例如，仰角较小的小区(或者卫星波束)的残留多普勒频偏较小，或者基站服务的是使用高精度晶振的终端，此时可能不需要启用随机接入前导的掩码功能，即随机接入前导使用和现有协议相同的生成过程，或者认为掩码序列中的元素为全1或1的缩放值。根据小区(或者卫星波束)或者服务终端的特性，增加是否使用随机接入前导掩码的配置功能：可以对小区(或者卫星波束)级指示参数进行划分，当参数处于某段区间时不启用掩码加扰功能，参数划分的方式是基站与终端约定的，或者是基站在广播信息中下发的，其中指示参数包括多普勒频偏值、公共往返传输时延、公共往返传输时延变化率、波束角度等等，这些指示参数为小区(或者卫星波束)内某参考点的对应参数，或者是某参考点对应参数加上一个偏移值；或者可以在广播信息中的至少一种、RRC信息、MAC元素或DCI内增加1个启用掩码的指示标记，例如在RRC的RACH配置信令中增加1个是否启用掩码的信令。
为便于理解，举例一种抗频偏随机接入前导及掩码序列的具体生成形式。以NR协议中普遍使用的31级Gold序列为例，生成掩码序列c(n)：
Figure PCTCN2020119184-appb-000017
Figure PCTCN2020119184-appb-000018
x 1(n+31)＝(x 1(n+3)+x 1(n))mod 2
x 2(n+31)＝(x 2(n+3)+x 2(n+2)+x 2(n+1)+x 2(n))mod 2
其中，N C＝1600，x 1(0)＝1,x 1(n)＝0,n＝1,2,...,30；x 2(n)是m序列，其中，生成m序列的种子为：
Figure PCTCN2020119184-appb-000019
掩码序列是与随机接入前导时频资源参数相关的序列。其中，例如组成掩码序列的m序列的种子由多个时频资源参数按一定运算规则获得，与种子相关的参数包括时频资源的起始符号s_id，起始时隙号t_id，频域资源号f_id及上行载波号ul_carrier_id等等。m序列种子的生成方式为：
c init＝(2 17(14·t_id+s_id)+2f_id+ul_carried_id)mod 2 31
利用上述种子及Gold序列生成规则产生掩码序列c(n)。
其中，终端侧和基站侧约定以1个ZC序列频域数据作为整体与掩码序列的一个元素c(n)相乘，则生成的掩码序列长度至少为N zc。ZC序列的频域数据加掩码后，映射到随机接入时频资源的相应子载波，终端侧通过IFFT生成最终发送的随机接入时域数据。
可以看出，上述举例了抗频偏接入前导的掩码序列的具体表现形式和生成方法。掩码序列可以使用不同形式的伪随机序列，序列生成可能与不同的参数相关，ZC序列频域数据还可能具有不同的加掩码的方式。在原始ZC序列生成的频域数据上加掩码，使得基站的接收序列子载波与本地序列子载波未对齐时，ZC序列的相关性被破坏，避免在上行同步时出现虚假相关峰值，从而影响上行定时位置的确定。
下面举例展示抗频偏前导序列基本格式的设计方法。
其中，在卫星通信系统中，终端发送的随机接入前导将同时受到较大的残留频偏和往返传输时延(差)影响。其中，按前述实施例所述方式生成的抗频偏前导序列具有抵抗残留频偏的能力，另外还需要设计相应的前导序列格式，在前导序列受到较大传输时延影响时，基站仍能利用该序列获取正确的上行定时位置。
对于上行信号残留频偏较大、用户往返传输时延(差)较小的场景，例如星下小区(或者卫星波束)，当往返传输时延(差)的影响不超过现有协议规定的前导序列格式的循环前缀长度时，终端仍能使用现有协议规定的前导序列格式，只需要在相应序列格式中填充前述实施例所述方式生成的抗频偏前导符号。
对于上行信号包含一定残留频偏、往返传输时延(差)较大的场景，例如边缘小区(或者卫星波束)，往返传输时延(差)通常会超过现有协议规定的前导序列格式的循环前缀 长度，因此终端需要使用新的前导序列格式，并使用新的前导序列填充方式。
其中，一种前导序列格式的设计例如基于如图5-A所示的随机接入前导序列的基本时域格式。随机接入前导格式应包含循环前缀、序列部分和保护间隔三个部分，假设前导序列总长度为T RA＝T CP+T SEQ+T GT，其中循环前缀部分的长度为
Figure PCTCN2020119184-appb-000020
自然数
Figure PCTCN2020119184-appb-000021
表示整数个前导符号，
Figure PCTCN2020119184-appb-000022
表示小数个前导符号，范围为
Figure PCTCN2020119184-appb-000023
T sym为一个前导符号的长度；序列部分的长度T SEQ＝N SEQT sym，N SEQ为正整数；保护间隔部分的长度为T GT。这里循环前缀和保护间隔的长度可能大于或者小于一个前导符号的长度T sym。
参见图5-B至图5-F，图5-B至图5-F举例示出了几种前导序列的格式。
举例来说，所述序列部分包括至少一个子序列A，此外，所述序列部分还可包括至少一个子序列B。所述子序列A包含至少一个前导符号，其中，所述子序列B包含至少一个前导符号，所述子序列A包含的前导符号不同于所述子序列B包含的前导符号；所述子序列A由频域序列Za经频域资源映射和时频变换而得到，所述频域序列Za基于ZC序列和掩码序列得到。
举例来说，在所有子序列A的长度相等，所有子序列B的长度相等的情况下，任意两个子序列B相邻的间隔至少大于或等于
Figure PCTCN2020119184-appb-000024
表示向上取整，其中，
Figure PCTCN2020119184-appb-000025
表示循环前缀包含的整数个前导符号，
Figure PCTCN2020119184-appb-000026
表示循环前缀包含的小数个前导符号。
举例来说，每个所述子序列A和每个所述子序列B的长度分别都大于或等于所述循环前缀的长度。
举例来说，所述随机接入前导序列包括的循环前缀的数量为一个，
其中，所述子序列A和子序列B位于所述循环前缀和所述保护间隔之间，或者所述子序列A和子序列B的时域叠加序列位于所述循环前缀和所述保护间隔之间。
举例来说，所述随机接入前导序列包括第一循环前缀和第二循环前缀；
其中，至少一个所述子序列A位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列B位于所述第二循环前缀和所述保护间隔之间；
或者，
至少一个所述子序列B位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列A位于所述第二循环前缀和所述保护间隔之间；
或者，
其中，所述第一循环前缀和所述第二循环前缀之间包括交替出现的至少一个所述子序列A和至少一个所述子序列B。
当循环前缀的长度大于一个前导符号时，基站无法利用仅填充一种前导符号的序列完成上行定时，此时序列中至少需要填充两种互不相同的前导符号，因此需要设计新的序列格式及前导符号填充方式。
假设通信场景要求循环前缀的长度大于一个前导符号，前导格式需填充两种互不相同的前导符号α、β，记抗频偏前导符号为α，另一种前导符号为β，前导序列格式的设计如图5-B至图5-E举例所示。
如图5-B的前导序列格式设计方式，图5-B中所示子序列A包含连续放置的至少一个前导符号，子序列A包含连续放置的至少一个前导符号，其中子序列A或者子序列B的其中一个由抗频偏前导符号α填充，另一个区域则填充前导符号β。进一步地，填充抗频偏前导符号α的区域至少包含两个连续的前导符号。
如图5-B的前导序列格式设计方式，图中所示子序列A与子序列B交替放置，每个子序列A包含连续放置的至少一个前导符号，其中，每个子序列B包含连续放置的至少一个前导符号，每个区域包含的前导符号数可以相同，也可以不同。其中子序列A或者子序列B的其中一个由抗频偏前导符号α填充，另一个区域则填充前导符号β。进一步地，至少有一个填充抗频偏前导符号α的区域至少包含两个连续的前导符号；当所有子序列A的长度相等、所有子序列B的长度相等时，那么，所有填充抗频偏前导符号α的区域至少包含两个连续的前导符号，相邻填充前导符号β的区域的间隔至少大于等于
Figure PCTCN2020119184-appb-000027
表示向上取整，即两个相邻的填充前导符号β的区域的起始前导符号索引号之差大于等于
Figure PCTCN2020119184-appb-000028
例如子序列B填充的是抗频偏前导α，那么还要求所有相邻的A区域的起始前导符号索引号之差至少大于等于
Figure PCTCN2020119184-appb-000029
反之亦然。
其中，当子序列A或者子序列B的其中一个区域填充前述实施例所述的抗频偏前导符号α时，假设该符号由根序号为u 1的ZC序列及相应掩码序列生成，另一个区域应填充与之不同的另一种前导符号β。另一种前导符号β可使用与抗频偏前导符号α相同的生成方式，但前导符号β的ZC序列根序号或者掩码序列的至少一种与前导符号α不同，即前导符号β与前导符号α可以使用相同的ZC序列、不同的掩码序列，或使用不同的ZC序列、相同的掩码序列，或者使用不同的ZC序列、不同的掩码序列；前导符号β也可以使用非抗频偏前导的形式，例如直接使用ZC序列填充、使用伪随机数填充，或者直接将这段符号置为全零。
为便于理解，举例一种具体的随机接入前导格式。如图5-F所示为一种可抵抗较大往返传输时延(差)影响的前导序列格式。
假设前导序列由长度为839的ZC序列生成，前导序列子载波宽度为1.25kHz，一个前导符号长度为0.8ms。如图5-F所示的前导序列格式的循环前缀长度为2.284ms，相当于2.855个前导符号，即该格式的循环前缀长度是在NR协议规定的前导格式1的循环前缀0.684ms的基础上增加了两个前导符号；序列部分包含6个前导符号，序列部分的第2、3、5、6个符号填充抗频偏前导符号α，第1、4个前导符号填充另一种前导符号β。这里，每个填充前导符号α的区域都包含连续两个前导符号，相邻的两个填充前导符号β的区域的起始前导符号索引号之差为3，满足大于等于
Figure PCTCN2020119184-appb-000030
的要求。
另一方面，前导序列格式中填充的前导符号α可由根序号为u的ZC序列及掩码序列c 1(n)生成，前导符号β由根序号为u的ZC序列及掩码序列c 2(n)生成，前导符号α和β是互不相同的符号。
可以看出，上述举例给出了一种适应于较大往返传输时延(差)场景的前导序列格式设计方案。通过在前导格式中填充至少两种互不相同的前导符号，令基站能够检测发送该格式前导序列的终端的上行定时位置，以满足卫星通信系统的需求。
参见图6-A，图6-A为本申请实施例举例的一种卫星通信方法的流程示意图。一种卫星 通信方法可包括：
601.接收随机接入前导序列；其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
602.基于接收到的随机接入前导序列进行上行时频估计以得到频偏估计值为
Figure PCTCN2020119184-appb-000031
所述
Figure PCTCN2020119184-appb-000032
由晶振误差和/或多普勒频偏引起的频偏构成。
603.向终端发送频偏估计指示，所述频偏估计指示用于指示出所述频偏估计值
Figure PCTCN2020119184-appb-000033
其中，所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
下面举例提供一些上行残留频偏估计值的反馈形式。
为了避免多用户之间的数据传输产生相互干扰，基站侧应向终端反馈通过上行初始同步获取的残留频偏估计值，以便终端调整频偏补偿值，消除后续发送的上行信号的残留频偏。基站应在RAR中向终端反馈频偏估计值。
残留频偏估计值的第一种指示方式为，在RAR中增加指示频偏估计值的字段。例如图6-B中展示了一种增加字段的方式，在MAC RAR增加长度为8比特频偏估计值反馈字段，途中增加的字段使用加粗字体表示。
在RAR窗口中指示的频偏数值，其表现形式可以是代表真实频偏数值的绝对频偏值，可以是与随机接入前导子载波、或者上行数据子载波成比例的归一化子载波频偏值。RAR中可以直接指示频偏数值，或者是指示频偏数值的缩放值，或者可以是指示频偏数值对应的某个索引号，其中，索引号与频偏数值的映射关系是基站与终端约定的，或是由基站下发的频偏数值索引表确定的。
残留频偏的第二种指示方式可为，尽量降低RAR中的字段占用，在RA-RNTI中增加隐式频偏指示。举例一种在RA-RNTI中增加隐式频偏指示的形式：
RA_RNTI＝1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+ 14×80×8×2×fre_est_id
其中，无下划线部分为NR协议规定的RA_RNTI计算部分，下划线部分为增加的隐式频偏指示部分。其中，由于NR协议规定RA-RNTI的取值范围为0x0001～0xFFEF，fre_est_id的取值为0,1,2。由于fre_est_id的取值少，可能仅包含部分的反馈频偏。
因为fre_est_id的取值范围较小，可以选择其作为整数倍归一化子载波频偏的指示，例如fre_est_id＝0,1,2分别代表-1,0,1个整数倍归一化前导序列子载波的频偏；或者作为若干个整数倍归一化子载波频偏的指示，例如fre_est_id＝0,1,2分别代表-4,0,4个整数倍归一化前导序列子载波的频偏。其中，fre_est_id与频偏值的映射关系可以是基站与终端约定的，也可为基站通过SIB1、OSI、MIB等广播信息中的至少一种指示的。其中，当参数fre_est_id的指示范围不足时，可以利用fre_est_id与RAR增加的字段联合指示反馈的频偏估计值。
在RA-RNTI中增加隐式频偏指示形式时，终端侧监听RAR时需要遍历fre_est_id的所有可能取值，来解扰PDCCH，获取其中包含的下行控制信息。
此外，为了维持终端在网络连接阶段的正常通信，基站侧可利用频偏跟踪功能，向终 端反馈频偏跟踪或与其相关的参数，以便终端消除后续发送的上行信号的残留频偏。
基站可选择向终端反馈通过跟踪获取的残留频偏估计值，频偏估计值的指示位置可以为用户级RRC信息、MAC元素(例如放在传输定时提前更新命令的MAC元素中)或者DCI，频偏估计值的指示形式可以是绝对频偏值，可以是归一化频偏值，可以是绝对或归一化频偏值的缩放值，或者是绝对或归一化频偏值的索引号，其中索引号与频偏值的映射关系可以是基站和终端约定的，或者是基站通过SIB、MIB等广播信息中的至少一种下发的。基站也可以向终端指示残留频偏的变化率，由于残留频偏变化率的变化非常小，该参数可以作为一个小区(或卫星波束)级参数在SIB、MIB等广播信息中的至少一种向终端指示，频偏变化率的指示形式可以是绝对频偏变化率、归一化频偏变化率、绝对或归一化频偏变化率的缩放值，或者是绝对或归一化频偏变化率的索引号，其中，索引号与频偏变化率的映射关系可以是基站和终端约定的，或者是基站通过广播信息中的至少一种下发的。另外，由于残留频偏的来源可能是多普勒频偏，也可能是收发晶振误差引起的频偏，基站侧还可以使用1个额外的比特指示频偏来源，以便收发双方进行相应处理，指示位置可以是广播信息中的至少一种，或者是RRC信息、MAC元素或DCI。
可以看出，上述举例提供了一些残留频偏的反馈方法，利用RAR中的字段直接或间接地反馈频偏估计值，或者在RA-RNTI中增加隐式频偏指示信息，进而来指示全部或者部分的频偏信息。上述举例方案考虑尽量降低频偏反馈的开销，同时反馈方式需具有一定的灵活性。
总的来说。本申请实施例举例的抗频偏前导序列在上行同步时，能排除较大归一化子载波频偏的影响，并保留ZC序列的相关特性。本申请实施例的上行同步算法对频偏范围不做限制，能同时获得定时与频偏估计值。本申请实施例的残留频偏反馈可能有多种不同的指示方式，提高了残留频偏反馈的灵活性。
下面还提供用于实施上述方案的相关设备。
参见图7，本申请实施例提供一种卫星通信设备700，包括：
发送单元710，用于生成随机接入前导序列，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
输出单元720，输出所述随机接入前导序列。
参见图8，本申请实施例提供一种卫星通信设备800，包括：
通信单元810，用于接收随机接入前导序列；所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到。
检测单元820，用于基于接收到的所述随机接入前导序列进行上行时频估计以得到频偏估计值为
Figure PCTCN2020119184-appb-000034
由晶振误差和/或多普勒频偏引起的频偏构成。
通信单元810还用于，向终端发送频偏估计指示，其中，所述频偏估计指示用于指示出所述频偏估计值
Figure PCTCN2020119184-appb-000035
例如所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
参见图9，本申请实施例还提供一种卫星通信设备900(卫星通信设备900如终端设备或地面基站或卫星等)，可以包括：相互耦合的处理器910和存储器920。其中，所述处理器用于调用所述存储器中存储的计算机程序，以执行本申请实施例提供的任意一种方法的部分或全部步骤。
本申请实施例还提供一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，其中，所述计算机程序被处理器执行，以完成本申请实施例提供的任意一种方法的部分或全部步骤。
本申请实施例还提供了一种包括指令的计算机程序产品，当所述计算机程序产品在用户设备上运行时，可以使得卫星通信设备执行本申请实施例提供的任意一种方法的部分或全部步骤。
参见图10，本申请实施例还提供一种通信装置1000，包括：输入接口电路1001，逻辑电路1002和输出接口电路1003；其中，所述逻辑电路用于执行本申请实施例提供的任意一种方法的部分或全部步骤。
参见图11，本申请实施例还提供一种通信装置1100，包括至少一个输入端1101、信号处理器1101和至少一个输出端1103；其中，所述信号处理器1102，用于执行本申请实施例提供的任意一种方法的部分或全部步骤。
本申请实施例还提供一种计算机可读存储介质，所述计算机可读存储介质存储有计算机程序，所述计算机程序被硬件(例如处理器等)执行，以实现本申请实施例中由任意设备执行的任意一种方法的部分或全部步骤。
本申请实施例还提供了一种包括指令的计算机程序产品，当所述计算机程序产品在计算机设备上运行时，使得所述这个计算机设备执行以上各方面的任意一种方法的部分或者全部步骤。
在上述实施例中，可全部或部分地通过软件、硬件、固件、或其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线)或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质(例如软盘、硬盘、磁带)、光介质(例如光盘)、或者半导体介质(例如固态硬盘)等。在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详 述的部分，可以参见其他实施例的相关描述。
在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置，也可以通过其它的方式实现。例如以上所描述的装置实施例仅仅是示意性的，例如所述单元的划分，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，例如多个单元或组件可结合或者可以集成到另一个系统，或一些特征可以忽略或不执行。另一点，所显示或讨论的相互之间的间接耦合或者直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者，也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例的方案的目的。
另外，在本申请各实施例中的各功能单元可集成在一个处理单元中，也可以是各单元单独物理存在，也可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，或者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(可为个人计算机、服务器或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质例如可包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁碟或光盘等各种可存储程序代码的介质。

Claims (26)

  1. 一种卫星通信方法，其特征在于，包括：
    生成随机接入前导序列，其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到；
    输出所述随机接入前导序列。
  2. 根据权利要求1所述的方法，其特征在于，
    x u,v(n)＝x u((n+C v)mod N zc)
    Figure PCTCN2020119184-appb-100001
    其中，u为ZC序列的根序号，x u(i)表示原始的ZC序列中的一个数据，
    其中，N zc为ZC序列长度，x u,v(n)表示经过循环移位处理的ZC序列中的一个数据，C v为循环移位；
    其中，
    Figure PCTCN2020119184-appb-100002
    Figure PCTCN2020119184-appb-100003
    其中，c(n)为掩码序列中的一个元素，
    Figure PCTCN2020119184-appb-100004
    表示频域序列中的一个数据。
  3. 根据权利要求1或2所述的方法，其特征在于，所述掩码序列为m序列、M序列或Gold序列，其中，所述掩码序列中的元素为1、-1或1、-1的缩放值。
  4. 根据权利要求1至3中任意一项所述的方法，其特征在于，所述掩码序列为全网通用的掩码序列，所述掩码序列为所有基站与终端约定的随机接入前导的掩码序列，所有基站和终端使用包含相同元素的掩码序列；
    或者，所述掩码序列是一个小区或卫星波束通用的掩码序列，所述掩码序列的生成与至少一个小区或卫星波束特定参数相关，其中，所述小区或卫星波束特定参数包括如下参数中的一种或者多种：小区或卫星波束索引号、数据子载波宽度索引号、同步信号块索引号或带宽部分索引号；
    或者，
    所述掩码序列是与随机接入时频资源相关的序列，所述掩码序列的生成与至少一个随机接入时频资源相关参数相关，其中，所述随机接入时频资源参数包括如下参数中的一种 或者多种：时频资源的起始符号、起始时隙号、频域资源号或上行载波号。
  5. 根据权利要求1至4中任意一项所述的方法，其特征在于，所述序列部分包括至少一个子序列A和至少一个子序列B，所述子序列A包含至少一个前导符号，所述子序列B包含至少一个前导符号，所述子序列A包含的前导符号不同于所述子序列B包含的前导符号；所述子序列A由频域序列Za经频域资源映射和时频变换而得到，所述频域序列Za基于ZC序列和掩码序列得到。
  6. 根据权利要求5所述的方法，其特征在于，在所有子序列A的长度相等，所有子序列B的长度相等的情况下，任意两个子序列B相邻的间隔至少大于或等于
    Figure PCTCN2020119184-appb-100005
    表示向上取整，其中，
    Figure PCTCN2020119184-appb-100006
    表示循环前缀包含的整数个前导符号，
    Figure PCTCN2020119184-appb-100007
    表示循环前缀包含的小数个前导符号。
  7. 根据权利要求5或6所述的方法，其特征在于，每个所述子序列A和每个所述子序列B的长度分别都大于或等于所述循环前缀的长度。
  8. 根据权利要求7所述的方法，其特征在于，所述随机接入前导序列包括的循环前缀的数量为一个，
    其中，所述子序列A和子序列B位于所述循环前缀和所述保护间隔之间，
    或者，所述子序列A和子序列B的时域叠加序列位于所述循环前缀和所述保护间隔之间。
  9. 根据权利要求7所述的方法，其特征在于，所述随机接入前导序列包括第一循环前缀和第二循环前缀；
    其中，至少一个所述子序列A位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列B位于所述第二循环前缀和所述保护间隔之间；
    或者，
    至少一个所述子序列B位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列A位于所述第二循环前缀和所述保护间隔之间；
    或者，
    其中，所述第一循环前缀和所述第二循环前缀之间包括交替出现的至少一个所述子序列A和至少一个所述子序列B。
  10. 一种卫星通信方法，其特征在于，包括：
    接收随机接入前导序列；其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到；
    基于接收到的所述随机接入前导序列进行上行时频估计以得到频偏估计值
    Figure PCTCN2020119184-appb-100008
    所述
    Figure PCTCN2020119184-appb-100009
    由晶振误差和/或多普勒频偏引起的频偏构成；
    向终端发送频偏估计指示，其中，所述频偏估计指示用于指示出所述频偏估计值
    Figure PCTCN2020119184-appb-100010
  11. 根据权利要求10所述的方法，其特征在于，所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
  12. 一种卫星通信设备，其特征在于，包括：
    生成单元，用于生成随机接入前导序列，其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到；
    输出单元，用于输出所述随机接入前导序列。
  13. 根据权利要求12所述的设备，其特征在于，
    x u,v(n)＝x u((n+C v)mod N zc)
    Figure PCTCN2020119184-appb-100011
    其中，u为ZC序列的根序号，x u(i)表示原始的ZC序列中的一个数据，
    其中，N zc为ZC序列长度，x u,v(n)表示经过循环移位处理的ZC序列中的一个数据，C v为循环移位；
    其中，
    Figure PCTCN2020119184-appb-100012
    Figure PCTCN2020119184-appb-100013
    其中，c(n)为掩码序列中的一个元素，
    Figure PCTCN2020119184-appb-100014
    表示频域序列中的一个数据。
  14. 根据权利要求12或13所述的设备，其特征在于，所述掩码序列为m序列、M序列或Gold序列，其中，所述掩码序列中的元素为1、-1或1、-1的缩放值。
  15. 根据权利要求12至14中任意一项所述的设备，其特征在于，所述掩码序列为全网通用的掩码序列，所述掩码序列为所有基站与终端约定的随机接入前导的掩码序列，所有 基站和终端使用包含相同元素的掩码序列；
    或者，所述掩码序列是一个小区或卫星波束通用的掩码序列，所述掩码序列的生成与至少一个小区或卫星波束特定参数相关，其中，所述小区或卫星波束特定参数包括如下参数中的一种或者多种：小区或卫星波束索引号、数据子载波宽度索引号、同步信号块索引号或带宽部分索引号；
    或者，
    所述掩码序列是与随机接入时频资源相关的序列，所述掩码序列的生成与至少一个随机接入时频资源相关参数相关，其中，所述随机接入时频资源参数包括如下参数中的一种或者多种：时频资源的起始符号、起始时隙号、频域资源号或上行载波号。
  16. 根据权利要求12至15中任意一项所述的设备，其特征在于，所述序列部分包括至少一个子序列A和至少一个子序列B，所述子序列A包含至少一个前导符号，所述子序列B包含至少一个前导符号，所述子序列A包含的前导符号不同于所述子序列B包含的前导符号；所述子序列A由频域序列Za经频域资源映射和时频变换而得到，所述频域序列Za基于ZC序列和掩码序列得到。
  17. 根据权利要求16所述的设备，其特征在于，在所有子序列A的长度相等，所有子序列B的长度相等的情况下，任意两个子序列B相邻的间隔至少大于或等于
    Figure PCTCN2020119184-appb-100015
    Figure PCTCN2020119184-appb-100016
    表示向上取整，其中，
    Figure PCTCN2020119184-appb-100017
    表示循环前缀包含的整数个前导符号，
    Figure PCTCN2020119184-appb-100018
    表示循环前缀包含的小数个前导符号。
  18. 根据权利要求16或17所述的设备，其特征在于，每个所述子序列A和每个所述子序列B的长度分别都大于或等于所述循环前缀的长度。
  19. 根据权利要求18所述的设备，其特征在于，所述随机接入前导序列包括的循环前缀的数量为一个，
    其中，所述子序列A和子序列B位于所述循环前缀和所述保护间隔之间，
    或者，所述子序列A和子序列B的时域叠加序列位于所述循环前缀和所述保护间隔之间。
  20. 根据权利要求18所述的设备，其特征在于，所述随机接入前导序列包括第一循环前缀和第二循环前缀；
    其中，至少一个所述子序列A位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列B位于所述第二循环前缀和所述保护间隔之间；
    或者，
    至少一个所述子序列B位于所述第一循环前缀和所述第二循环前缀之间，至少一个所述子序列A位于所述第二循环前缀和所述保护间隔之间；
    或者，
    其中，所述第一循环前缀和所述第二循环前缀之间包括交替出现的至少一个所述子序列A和至少一个所述子序列B。
  21. 一种卫星通信设备，其特征在于，包括：
    通信单元，用于接收随机接入前导序列；其中，所述随机接入前导序列包括循环前缀、序列部分和保护间隔，所述序列部分由频域序列经频域资源映射和时频变换而得到，所述频域序列基于ZC序列和掩码序列得到；
    检测单元，用于基于接收到的所述随机接入前导序列进行上行时频估计以得到频偏估计值
    Figure PCTCN2020119184-appb-100019
    所述
    Figure PCTCN2020119184-appb-100020
    由晶振误差和/或多普勒频偏引起的频偏构成；
    所述通信单元还用于向终端发送频偏估计指示，其中，所述频偏估计指示用于指示出所述频偏估计值
    Figure PCTCN2020119184-appb-100021
  22. 根据权利要求21所述的设备，其特征在于，所述频偏估计指示携带在媒介访问控制随机接入响应MAC RAR的频偏估计值反馈字段；或者，所述频偏估计指示携带在随机接入无线网络临时标识RA-RNTI中。
  23. 一种通信装置，其特征在于，包括：
    相互耦合的处理器和存储器；
    其中，所述处理器用于调用所述存储器中存储的计算机程序，以执行权利要求1至9中任意一项或者10至11中任意一项所述的方法。
  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存储有计算机程序，所述计算机程序被处理器执行时能够完成权利要求1至9中任意一项或者10至11中任意一项所述的方法。
  25. 一种通信装置，其特征在于，包括：
    至少一个输入端、信号处理器和至少一个输出端；其中，所述信号处理器，用于执行权利要求1至9中任意一项或者10至11中任意一项所述的方法。
  26. 一种通信装置，包括：输入接口电路，逻辑电路和输出接口电路，其中，
    所述逻辑电路，用于执行如权利要求1-9中任一所述的方法，或者，执行如权利要求10-11任一项所述的方法。
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