A method and apparatus for random access, satellite and UE

Abstract

The application discloses a random access method and device, a satellite and a UE, and relates to the field of satellite communication. The method comprises the following steps: receiving an SSB transmitted by a satellite in at least one downlink subframe; and initiating random access to the satellite in at least one uplink subframe; wherein the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframes in the TDD system frame are located before the uplink subframes. The application provides a new random access method, random access is performed based on a longer TDD system frame, resource utilization can be improved, the downlink subframes are located before the uplink subframes, and the efficiency of UE access to a network is improved.

Description

Technical Field

[0001] This application relates to the field of satellite communication technology, and in particular to a method and apparatus for random access, a satellite, and a UE. Background Technology

[0002] In TDD (Time Division Duplex) systems, uplink and downlink share the same frequency bandwidth. In satellite communication systems, the round-trip time between satellite and ground is relatively large, resulting in a large guard interval in the TDD frame structure and low resource utilization. To improve resource utilization in TDD systems, the RO (Random Access Occurrence) needs to be redesigned. However, the RO-based random access mechanism in 5G NR standard TDD systems is not suitable for satellite communication systems. Therefore, a new random access scheme is needed specifically for satellite communication systems to improve the random access efficiency of UE (User Equipment). Summary of the Invention

[0003] The purpose of this application is to provide a method and apparatus for random access, a satellite, and a UE. This addresses the issue that random access based on the existing 5G NR standard's TDD system RO is no longer suitable for satellite communication systems.

[0004] In a first aspect, embodiments of this application provide a method for random access, the method being applied to a UE, the method comprising: In at least one downlink subframe, receive the SSB transmitted by the satellite; In at least one uplink subframe, initiate random access to the satellite; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0005] In some possible embodiments, there is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

[0006] In some possible embodiments, the length of the TDD system frame is the same as the length of two NR system frames.

[0007] In some possible embodiments, the TDD system frame uses an NR system frame number, and the NR system frame number of at least one uplink subframe initiating random access is an odd number.

[0008] In some possible embodiments, the TDD system frame adopts the NR system frame number, wherein: At least one uplink subframe that initiates random access is at least a subset of uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB transmitted by the satellite is a subframe that is at least a portion of the downlink subframes with an even-numbered NR system frame.

[0009] In some possible embodiments, at least one uplink subframe initiating random access is located after the starting uplink subframe of the TDD system frame, and is at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0010] In some possible embodiments, the number of at least one uplink subframes initiating random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices.

[0011] In some possible embodiments, any uplink subframe that initiates random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

[0012] In some possible embodiments, the first PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6 or 7.

[0013] In some possible embodiments, the method further includes: In the random access response (RAR) reception window of the downlink subframe, the random access response sent by the satellite is received; The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

[0014] In some possible embodiments, a beam spatial multiplexing instruction transmitted by the satellite is received, and multiple uplink beams employing spatial multiplexing are determined.

[0015] Secondly, embodiments of this application provide a method for random access applied to satellites, the method further comprising: In at least one downlink subframe, an SSB is sent to the UE; In at least one uplink subframe, receive random access initiated by the UE; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0016] In some possible embodiments, there is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

[0017] In some possible embodiments, the length of the TDD system frame is the same as the length of two NR system frames.

[0018] In some possible embodiments, the TDD system frame uses an NR system frame number, and the NR system frame number of at least one uplink subframe for receiving random access is an odd number.

[0019] In some possible embodiments, the TDD system frame adopts the NR system frame number, wherein: Receive at least one uplink subframe of random access, which is at least a portion of the uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB sent to the UE is at least a portion of the downlink subframes with an even-numbered NR system frame.

[0020] In some possible embodiments, at least one uplink subframe of random access is received, located after the starting uplink subframe of the TDD system frame, and at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0021] In some possible embodiments, the number of at least one uplink subframes received for random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices.

[0022] In some possible embodiments, receiving any uplink subframe of random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

[0023] In some possible embodiments, the first PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6 or 7.

[0024] In some possible embodiments, the method further includes: In the random access response (RAR) receive window of the downlink subframe, a random access response is sent to the UE; The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

[0025] In some possible embodiments, the method further includes: A beam spatial multiplexing indication is sent to the UE to indicate multiple uplink beams using spatial multiplexing.

[0026] Thirdly, another embodiment of this application also provides a random access device, the device comprising: The SSB receiving module is used to receive SSBs transmitted by the satellite in at least one downlink subframe. A random access initiation module is used to initiate random access to the satellite in at least one uplink subframe; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0027] Fourthly, another embodiment of this application also provides a random access device, comprising: The SSB transmission module is used to transmit an SSB to the UE in at least one downlink subframe. A random access receiving module is used to receive random access initiated by the UE in at least one uplink subframe; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0028] Fifthly, another embodiment of this application also provides a user terminal (UE), including at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor using the random access method provided in the first aspect above.

[0029] In a sixth aspect, embodiments of this application also provide a satellite, including at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to perform the steps of the random access method provided in the second aspect above.

[0030] In a seventh aspect, another embodiment of this application also provides a computer storage medium storing a computer program for causing a computer to perform the steps of the methods provided in the first or second aspect of the embodiments of this application.

[0031] In this embodiment, the uplink and downlink subframes of the random access procedure are part of the TDD system frame. The length of the TDD system frame is the same as the length of at least two NR system frames. Due to the use of a longer frame length, it is not affected by satellite-to-ground round-trip delay, which can improve resource utilization. The downlink subframe in the TDD system frame is located before the uplink subframe, and the random access position is on the uplink subframe. In this way, the uplink subframe for random access is located in the later part of the TDD system frame, making the random access of the UE more efficient.

[0032] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of an application environment according to an embodiment of this application; Figure 2 This is a flowchart of a random access method applied to a UE according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating an example of random access using configured RO and RAR according to an embodiment of this application; Figure 4 This is a flowchart of a random access method for satellites provided according to an embodiment of this application; Figure 5 This is a structural diagram of a random access device according to an embodiment of this application; Figure 6 This is a schematic diagram of another random access device according to one embodiment of this application; Figure 7 This is a schematic diagram of a UE structure according to an embodiment of this application; Figure 8 This is a structural diagram of a satellite according to an embodiment of this application. Detailed Implementation

[0035] To further illustrate the technical solutions provided in the embodiments of this application, a detailed description is provided below in conjunction with the accompanying drawings and specific implementation methods. Although the embodiments of this application provide method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on conventional or non-inventive effort. For steps that do not logically have a necessary causal relationship, the execution order of these steps is not limited to the execution order provided in the embodiments of this application. In actual processing or when the control device executes the method, it may be executed sequentially or in parallel according to the method shown in the embodiments or drawings.

[0036] Given that random access via RO in TDD systems of the 5G NR standard is not applicable to satellite communication systems, this application proposes a random access method, apparatus, satellite, and UE. It provides a random access approach that optimizes the RO resource configuration of the TDD system. The random access method is based on the optimized TDD system frame configuration and is suitable for satellite communication systems, improving the efficiency of UE random access to the network.

[0037] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0038] The random access method in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0039] See Figure 1 This is a schematic diagram of an application environment according to an embodiment of this application.

[0040] like Figure 1 As shown, this application environment includes multiple satellites located on the orbital plane in a satellite communication system and UEs communicating with the satellites. Exemplarily, this includes satellites 102_1, 102_2, ..., 102_N in the figure, where N is a positive integer, and its size is determined according to specific needs and scenarios in practice. UE101 communicates with other target UEs 103 via satellite.

[0041] It should be noted that the above system architecture is merely an example illustrating the system architecture applicable to the embodiments of this application. The system architecture applicable to the embodiments of this application is different from that of the traditional system architecture. Figure 1 The system architecture shown can also add other entities or remove some entities.

[0042] Figure 2 This illustration shows a flowchart of a random access method provided in one embodiment of the present application, applied to a UE, including: Step 201: Receive the SSB transmitted by the satellite in at least one downlink subframe; Step 202: In at least one uplink subframe, initiate random access to the satellite; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0043] In related technologies, TDD system frames adopt a conventional 10ms wireless frame structure, with a relatively large proportion of flexible resources allocated to the guard interval, approximately 6ms. The time available for data transmission in each frame is only 4ms, resulting in relatively low effective transmission efficiency.

[0044] To adapt to the application scenarios of low-Earth orbit satellites, the length of the TDD system frame in this embodiment is the same as the length of at least two NR system frames, using a longer frame to improve system efficiency.

[0045] In this embodiment, the subframes in the TDD system frame include uplink subframes and downlink subframes, wherein at least one downlink subframe is used to transmit SSB, and at least one uplink subframe is RO, used by the UE to initiate random access. The downlink subframe in the TDD system frame is located before the uplink subframe, so that the uplink subframe for random access is located in the later part of the TDD system frame, making the network's random access more efficient.

[0046] For satellite communication TDD systems, uplink and downlink share the same frequency bandwidth, thus uplink and downlink signal interference needs to be considered. To avoid inter-uplink and downlink interference, a guard interval must be set between uplink and downlink resources. As one possible implementation, the downlink subframe and uplink subframe have a guard interval, which is related to the satellite-to-ground round-trip time (RTT). Specifically, based on the RTT in the satellite communication system, subframes belonging to the guard interval located between the downlink and uplink subframes are configured, and the uplink and downlink subframes of the TDD system are arranged in sequential order for TDD system frame configuration, with the downlink subframe preceding the uplink subframe, and a guard interval in between. Taking a low-Earth orbit satellite with an altitude of 500 km and a terminal elevation angle of 35 degrees as an example, the round-trip time (RTT) is approximately 3.39~5.6 ms, and the guard interval between the uplink and downlink subframes of the satellite TDD system needs to be greater than the RTT.

[0047] As an example, the length of a TDD system frame for a low-Earth orbit satellite is designed to be the same as that of two NR system frames, containing 20 subframes. Assuming a subcarrier spacing of 30 kHz and a TDD cycle of 40 time slots, each TDD system frame first configures downlink subframes, occupying 11 subframes, then a guard interval of 1 subframe, and finally 8 uplink subframes.

[0048] The RO configuration for 5G NR systems is detailed in section 6.3.3.2 of the TS 38.211 specification, specifically in Tables 6.3.3.2-2 to 6.3.3.2-4. These tables provide the PRACH (Physical Random Access Channel) configuration index, preamble format, RO configuration period, subframe number, start symbol index, number of PRACH slots in each subframe, and number of ROs in each slot. PRACH represents the random access signal.

[0049] The existing RO configuration in the 5G NR standard is difficult to directly apply to TDD satellite communication systems because it does not take into account the impact of satellite beam hopping. The NR configuration table shows RO configuration periods of every 16, 8, 4, and 1 NR system frames, which are incompatible with the TDD frame format design in current satellite communication systems. Although the RO configuration period of every 2 NR system frames in the table matches the TDD frame period, the subframe position of the RO is incompatible with the pre-allocated uplink subframe position in TDD, requiring adaptive modification.

[0050] In the 3GPP FR1 PRACH and RO configuration tables for TDD mode, a configuration period of 1 frame is too dense and may occupy the downlink frame time slot position of TDD; while NR system frames with configuration periods of 4, 8, and 16 are too sparse and will affect access efficiency. In the embodiment of this application, the length of the TDD system frame is the same as the length of two NR system frames. Therefore, the configuration period of RO is the length of two NR system frames. The RO used to initiate random access is configured on the uplink subframe. Since the RO is located in the later part of the TDD system frame, the scheduling of uplink data is staggered with the timing of RO as much as possible, so that the uplink resources of the system are fully utilized, which is suitable for random access in satellite communication systems.

[0051] The aforementioned SSB (Synchronization Signal / PBCH Block) is configured on the downlink subframe. The satellite transmits the SSB in the downlink subframe configured to transmit the SSB. The UE receives the SSB transmitted by the satellite and achieves signal synchronization with the satellite.

[0052] In some possible embodiments, at least one uplink subframe initiating random access is located after the starting uplink subframe of the TDD system frame, and is at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0053] To reduce signal interference between uplink and downlink on the same wavelength, this embodiment configures the uplink RO (Resource Origin) for random access at at least N subframes from the starting uplink subframe, thus placing it in the later part of the uplink subframe. Simultaneously, to correspond with the downlink SSB (Segment Subframe), the same number of uplink subframes are configured as ROs for random access based on the number of SSBs, and a PRACH configuration index is determined to index this configuration, resulting in different PRACH configurations. During UE-satellite communication, the corresponding PRACH index can be determined based on the number of SSBs, and the corresponding PRACH configuration can be found using this index. Random access is then performed based on the found PRACH configuration. For example, if the downlink subframe is configured to access 4 wavelengths, with 1 SSB transmitted per wavelength, then the uplink subframe is configured to access the same 4 wavelengths, with 1 RO resource configured per wavelength, and the corresponding PRACH configuration is obtained.

[0054] In this embodiment, the length of the TDD system frame is the same as the length of two NR system frames. The TDD system frame uses the NR system frame number. At least some subframes in the first NR system frame number are downlink subframes, and at least some subframes in the second NR system frame number are uplink subframes. A guard interval is left between the subframes of the two NR system frame numbers. In some possible embodiments, at least one uplink subframe initiating random access is at least one subframe in the uplink subframes with odd-numbered NR system frame numbers; at least one downlink subframe receiving the SSB transmitted by the satellite is at least one subframe in the downlink subframes with even-numbered NR system frame numbers.

[0055] In this embodiment of the application, the NR system frame number of at least one uplink subframe initiating random access is odd. Specifically, at least one uplink subframe with an odd NR system frame number is configured as a random access opportunity (RO) for random access.

[0056] Because TDD systems have strict timing rules for uplink and downlink time slot configuration, the situation where the UE receives the random access response within the RAR receive window after sending random access via PRACH according to the configured RO differs from that in NR. Currently, the NR RAR window opens after sending PRACH and waiting for RTT, without considering the impact of beam hopping. If the RAR window opens too early, the UE needs to wait for a longer period, which consumes the UE's power.

[0057] In some possible embodiments, the random access response (RAR) sent by the satellite is received during the random access response (RAR) receiving window of the downlink subframe; wherein the starting position of the RAR receiving window is located at the start time of the next downlink subframe of the UE's wavelength.

[0058] According to the TDD system frame structure, the RAR receive window does not need to be opened immediately after the PRACH sends the random access signal. Instead, it can be opened at the beginning of the next downlink subframe of the UE's current wavelength (i.e., the TDD system frame in which the UE sends the random access signal). This effectively avoids the UE opening the RAR receive window too early for detection, thus wasting UE energy.

[0059] Unlike FDD mode, in TDD mode, the opening of the RAR receive window is related to the RO timing, uplink and downlink time slot configuration, and beam hopping access period. The following is an example of random access using the configured RO and RAR in an embodiment of this application, such as... Figure 3 As shown, SSB represents downlink synchronization signal, RO represents uplink random access opportunity, gNB represents satellite base station side, UE represents terminal side, and RAR window represents the window time for UE to detect downlink RAR signal.

[0060] from Figure 3 It can be seen that the RAR window opens at the beginning of the next downlink subframe of the UE's current wavelength. This configuration method for opening the RAR window is more precise and detailed, effectively preventing the UE from opening the RAR window too early for blind detection and consuming power, thus saving UE power consumption.

[0061] In some possible embodiments, the number of at least one uplink subframes initiating random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices. Specifically, it may include, but is not limited to, the following PRACH configuration: a first PRACH configuration index, the subframe number of the at least one uplink subframe initiating random access is 6, 7, 8, or 9, that is, the subframe number of the uplink subframe where the RO is located is 6, 7, 8, or 9.

[0062] The RO resource configuration method of the satellite communication TDD system in this embodiment makes full use of the efficiency of TDD uplink time-frequency resources by configuring ROs in the uplink subframes belonging to the tail, thus better avoiding the interference problem between uplink and downlink in the TDD system. On the other hand, the number of RO configurations corresponds to the number of downlink SSBs, which is conducive to realizing the access of UEs on the corresponding SSBs within a TDD cycle, saving UE waiting time. The configuration scheme of the PRACH of the first PRACH configuration index of the TDD system is shown in Table 1: Table 1

[0063] The Preamble format is B4, n fThis indicates the NR system frame number. A group of ROs is configured every two NR system frames, and only in odd-numbered NR system frames (corresponding to uplink frames). The subframe number equipped with the RO is the subframe number {6,7,8,9} in the following NR system frame. The RO is configured at the end of the uplink frame to create time separation between it and the downlink frame accessing the corresponding spectral bit, thus avoiding uplink-downlink interference. The above PRACH configuration describes only some information items; the configuration of other information items is the same as in existing technology and will not be listed in detail here.

[0064] Current RO configurations in 3GPP schemes are all designed for single beams and do not consider spatial division multiplexing. If a system uses multiple uplink beams, the same RO opportunities can be shared through spatial division multiplexing, which can make more efficient use of RO opportunities and provide the system with more access opportunities.

[0065] Considering that a spaceborne base station may have more uplink beams than downlink beams, resulting in one downlink beam corresponding to multiple uplink beams, a time-division multiplexing (RTD) configuration with spatial division multiplexing can be considered in this case.

[0066] For uplink beams using spatial division multiplexing, any uplink subframe initiating random access in this embodiment corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing. Existing NR RO resource configurations do not support beam spatial division multiplexing mode, requiring the addition of relevant indications. If the UE uses spatial division multiplexing, the satellite sends a beam spatial division multiplexing indication to the UE to indicate multiple uplink beams using spatial division multiplexing. The UE receives the beam spatial division multiplexing indication sent by the satellite and determines the multiple uplink beams using spatial division multiplexing.

[0067] For example, a 2-bit signaling representation can be defined to indicate the uplink beam spatial multiplexing configuration, wherein: 00 indicates that one downlink beam corresponds to one uplink beam; 01 indicates that one downlink beam corresponds to two uplink beams; 10 indicates that one downlink beam corresponds to three uplink beams; 11 indicates that one downlink beam corresponds to four uplink beams.

[0068] Beam spatial multiplexing indicators can use a small amount of bit data to indicate key information and effectively distinguish different spatial multiplexing modes. By adding uplink multi-beam spatial multiplexing, interference can be reduced, the utilization rate of the same time slot can be improved, and multiple UEs can access the same RO using different beams, thereby improving the system's access efficiency.

[0069] For example, if there are 4 uplink beams corresponding to one SSB, one RO can be configured in the time domain to correspond to the 4 beams of spatial division multiplexing, forming 4 RO opportunities, as shown in Table 2: Table 2

[0070] For example, there can be 2 uplink beams corresponding to one SSB, so each component can be configured with 2 ROs in the time domain. Four ROs can be obtained through spatial division. The ROs are sorted in ascending order by beam number, as shown in Table 3.

[0071] Table 3

[0072] To support spatial multiplexing, the following PRACH configuration can be obtained based on the above configuration method: The second PRACH configuration index corresponds to subframe number 6 of at least one uplink subframe initiating random access, i.e., subframe number 6 of the uplink subframe where the RO is located. The third PRACH configuration index corresponds to subframe numbers 6 and 7 of at least one uplink subframe initiating random access, i.e., subframe numbers 6 and 7 of the uplink subframe where the RO is located. Specifically, Table 1 is upgraded by adding PRACH configuration indices 2 and 3, corresponding to uplink 4-beam and uplink 2-beam scenarios, respectively. The specific PRACH configuration schemes for the second and third PRACH configuration indices are shown in Table 4. Table 4

[0073] The above PRACH configuration is for some information items. The configuration of other information items is the same as in the existing technology and will not be listed in detail here.

[0074] Based on the TDD system frames obtained by the random access method provided in the above embodiments, this application also provides a random access method applied to satellites, such as... Figure 4 As shown, the method includes: Step 401: In at least one downlink subframe, send an SSB to the UE; Step 402: In at least one uplink subframe, receive a random access request initiated by the UE; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0075] In some possible embodiments, there is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

[0076] In some possible embodiments, the length of the TDD system frame is the same as the length of two NR system frames.

[0077] In some possible embodiments, the TDD system frame uses an NR system frame number, and the NR system frame number of at least one uplink subframe for receiving random access is an odd number.

[0078] In some possible embodiments, the TDD system frame adopts the NR system frame number, wherein: Receive at least one uplink subframe of random access, which is at least a portion of the uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB sent to the UE is at least a portion of the downlink subframes with an even-numbered NR system frame.

[0079] In some possible embodiments, at least one uplink subframe of random access is received, located after the starting uplink subframe of the TDD system frame, and at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0080] In some possible embodiments, the number of at least one uplink subframes received for random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices.

[0081] In some possible embodiments, receiving any uplink subframe of random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

[0082] In some possible embodiments, the first PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6 or 7.

[0083] In some possible embodiments, the method further includes: In the random access response (RAR) receive window of the downlink subframe, a random access response is sent to the UE; The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

[0084] In some possible embodiments, the method further includes: A beam spatial multiplexing indication is sent to the UE to indicate multiple uplink beams using spatial multiplexing.

[0085] Based on the same inventive concept, this application also provides a random access device, such as... Figure 5 As shown, the device includes: SSB receiver module 501 is used to receive SSB transmitted by the satellite in at least one downlink subframe; The random access initiation module 502 is used to initiate random access to the satellite in at least one uplink subframe; Wherein, the at least one downlink subframe is at least one uplink subframe that is a subframe in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0086] In some possible embodiments, there is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

[0087] In some possible embodiments, the length of the TDD system frame is the same as the length of two NR system frames.

[0088] In some possible embodiments, the TDD system frame uses an NR system frame number, and the NR system frame number of at least one uplink subframe initiating random access is an odd number.

[0089] In some possible embodiments, the TDD system frame adopts the NR system frame number, wherein: At least one uplink subframe that initiates random access is at least a subset of uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB transmitted by the satellite is a subframe that is at least a portion of the downlink subframes with an even-numbered NR system frame.

[0090] In some possible embodiments, at least one uplink subframe initiating random access is located after the starting uplink subframe of the TDD system frame, and is at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0091] In some possible embodiments, the number of at least one uplink subframes initiating random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices.

[0092] In some possible embodiments, any uplink subframe that initiates random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

[0093] In some possible embodiments, the first PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6 or 7.

[0094] In some possible embodiments, it also includes: The random access response receiving module is used to receive the random access response sent by the satellite in the random access response (RAR) receiving window of the downlink subframe. The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

[0095] In some possible embodiments, it also includes: The spatial division multiplexing module is used to receive the beam spatial division multiplexing instruction sent by the satellite and determine multiple uplink beams that adopt spatial division multiplexing.

[0096] Based on the same inventive concept, this application also provides a random access device, such as... Figure 6 As shown, the device includes: SSB transmission module 601 is used to transmit SSB to UE in at least one downlink subframe; The random access receiving module 602 is used to receive random access initiated by the UE in at least one uplink subframe; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe.

[0097] In some possible embodiments, there is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

[0098] In some possible embodiments, the length of the TDD system frame is the same as the length of two NR system frames.

[0099] In some possible embodiments, the TDD system frame uses an NR system frame number, and the NR system frame number of at least one uplink subframe for receiving random access is an odd number.

[0100] In some possible embodiments, the TDD system frame adopts the NR system frame number, wherein: Receive at least one uplink subframe of random access, which is at least a portion of the uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB sent to the UE is at least a portion of the downlink subframes with an even-numbered NR system frame.

[0101] In some possible embodiments, at least one uplink subframe of random access is received, located after the starting uplink subframe of the TDD system frame, and at least N subframes away from the starting uplink subframe, where N is a set positive integer.

[0102] In some possible embodiments, the number of at least one uplink subframes received for random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices.

[0103] In some possible embodiments, receiving any uplink subframe of random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

[0104] In some possible embodiments, the first PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6 or 7.

[0105] In some possible embodiments, it also includes: The random access response sending module is used to send a random access response to the UE in the random access response (RAR) receiving window of the downlink subframe. The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

[0106] In some possible embodiments, it also includes: The spatial division multiplexing indication module is used to send a beam spatial division multiplexing indication to the UE to indicate multiple uplink beams using spatial division multiplexing.

[0107] Based on the same inventive concept, embodiments of this application provide a user terminal (UE), such as... Figure 7 As shown, it includes at least one processor 701; and a memory 702 communicatively connected to the at least one processor; wherein the memory 702 stores instructions executable by the at least one processor 701, the instructions being executed by the at least one processor to perform the random access method for a UE provided in the above embodiments.

[0108] Based on the same inventive concept, embodiments of this application provide a satellite, such as... Figure 8As shown, it includes at least one processor 801; and a memory 802 communicatively connected to the at least one processor; wherein the memory 802 stores instructions executable by the at least one processor 801, the instructions being executed by the at least one processor 801 to perform the steps of the random access method for satellites provided in the above embodiments.

[0109] This application also provides a computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the steps of the random access method performed by the UE provided in the above embodiments, or the steps of the random access method performed by the satellite provided in the above embodiments. For example, the computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0110] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0111] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for random access, characterized in that, This method is applied to a UE, and the method includes: In at least one downlink subframe, receive the SSB transmitted by the satellite; In at least one uplink subframe, initiate random access to the satellite; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe; At least one uplink subframe that initiates random access is located after the starting uplink subframe of the TDD system frame, and is at least N subframes away from the starting uplink subframe, where N is a set positive integer. The number of uplink subframes that initiate random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices; The first PRACH configuration index corresponds to at least one uplink subframe that initiates random access, located at the end of the TDD system frame; The second and third PRACH configuration indices are used to support spatial multiplexing.

2. The method according to claim 1, characterized in that, There is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

3. The method according to claim 1, characterized in that, The length of the TDD system frame is the same as the length of the two NR system frames.

4. The method according to claim 1, characterized in that, The TDD system frame uses the NR system frame number, and the NR system frame number of at least one uplink subframe that initiates random access is an odd number.

5. The method according to claim 3, characterized in that, The TDD system frame uses the NR system frame number, where: At least one uplink subframe that initiates random access is at least a subset of uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB transmitted by the satellite is a subframe that is at least a portion of the downlink subframes with an even-numbered NR system frame.

6. The method according to claim 1, characterized in that, Any uplink subframe that initiates random access corresponds to one uplink beam or multiple uplink beams using spatial division multiplexing.

7. The method according to claim 1, characterized in that, The first PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe that initiates random access, which is 6 or 7.

8. The method according to claim 1, characterized in that, Also includes: In the random access response (RAR) reception window of the downlink subframe, the random access response sent by the satellite is received; The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

9. The method according to claim 1, characterized in that, Also includes: Receive the beam spatial multiplexing instruction sent by the satellite and determine multiple uplink beams to be used for spatial multiplexing.

10. A method for random access, characterized in that, Applied to satellites, the method includes: In at least one downlink subframe, an SSB is sent to the UE; In at least one uplink subframe, receive random access initiated by the UE; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe; Receive at least one uplink subframe of random access, located after the starting uplink subframe of the TDD system frame, and not less than N subframes away from the starting uplink subframe, where N is a set positive integer; The number of uplink subframes received via random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices; The first PRACH configuration index corresponds to at least one uplink subframe that initiates random access, located at the end of the TDD system frame; The second and third PRACH configuration indices are used to support spatial multiplexing.

11. The method according to claim 10, characterized in that, There is a guard interval between the downlink subframe and the uplink subframe, and the guard interval is related to the satellite-to-ground round-trip time delay.

12. The method according to claim 10, characterized in that, The length of the TDD system frame is the same as the length of the two NR system frames.

13. The method according to claim 10, characterized in that, The TDD system frame uses the NR system frame number, and the NR system frame number of at least one uplink subframe for random access is odd.

14. The method according to claim 12, characterized in that, The TDD system frame uses the NR system frame number, where: Receive at least one uplink subframe of random access, which is at least a portion of the uplink subframes with odd NR system frame numbers; At least one downlink subframe of the SSB sent to the UE is at least a portion of the downlink subframes with an even-numbered NR system frame.

15. The method according to claim 10, characterized in that, Receive any uplink subframe of random access, corresponding to one uplink beam or multiple uplink beams using spatial division multiplexing.

16. The method according to claim 10, characterized in that, The first PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6, 7, 8, or 9. The second PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6. The third PRACH configuration index corresponds to the subframe number of at least one uplink subframe for receiving random access, which is 6 or 7.

17. The method according to claim 10, characterized in that, Also includes: In the random access response (RAR) receive window of the downlink subframe, a random access response is sent to the UE; The starting position of the RAR receiving window is located at the start time of the next downlink subframe of the wavelength where the UE is located.

18. The method according to claim 10, characterized in that, Also includes: A beam spatial multiplexing indication is sent to the UE to indicate multiple uplink beams using spatial multiplexing.

19. A device for random access, characterized in that, The device includes: The SSB receiving module is used to receive SSBs transmitted by the satellite in at least one downlink subframe. A random access initiation module is used to initiate random access to the satellite in at least one uplink subframe; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe; At least one uplink subframe that initiates random access is located after the starting uplink subframe of the TDD system frame, and is at least N subframes away from the starting uplink subframe, where N is a set positive integer. The number of uplink subframes that initiate random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices; The first PRACH configuration index corresponds to at least one uplink subframe that initiates random access, located at the end of the TDD system frame; The second and third PRACH configuration indices are used to support spatial multiplexing.

20. A device for random access, characterized in that, include: The SSB transmission module is used to transmit an SSB to the UE in at least one downlink subframe. A random access receiving module is used to receive random access initiated by the UE in at least one uplink subframe; Wherein, the at least one downlink subframe and the at least one uplink subframe are subframes in a TDD system frame, the length of the TDD system frame is the same as the length of at least two NR system frames, and the downlink subframe in the TDD system frame is located before the uplink subframe; Receive at least one uplink subframe of random access, located after the starting uplink subframe of the TDD system frame, and not less than N subframes away from the starting uplink subframe, where N is a set positive integer; The number of uplink subframes received via random access is the same as the number of SSBs, and different numbers correspond to different PRACH configuration indices; The first PRACH configuration index corresponds to at least one uplink subframe that initiates random access, located at the end of the TDD system frame; The second and third PRACH configuration indices are used to support spatial multiplexing.

21. A user terminal (UE), characterized in that, The method includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor according to any one of claims 1 to 9.

22. A satellite, characterized in that, It includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor according to any one of claims 10 to 18.

23. A computer storage medium, characterized in that, The computer storage medium stores a computer program that causes the computer to perform the method as described in any one of claims 1 to 9, or to perform the method as described in any one of claims 10 to 18.

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