A random access method, device and storage medium

Abstract

The application discloses a random access method, device and storage medium, comprising: a UE receiving a beam signal, wherein the beam signal carries a beam coverage area number, the beam coverage area is an area covered by a beam transmitted by a communication satellite on the ground, and each beam coverage area has a preset number; the UE determining an area where the UE is located according to the beam coverage area number; the UE determining a TA according to a positional relationship between the area and the communication satellite, wherein the positional relationship is obtained by the UE in advance; and the UE initiating random access on a PRACH using a preamble in a RO agreed with the communication satellite according to the TA. According to the application, the UE can know the location, and the TA can be determined according to the positional relationship between the area and the communication satellite, such as the distance between the satellite and the ground, and the random access is initiated according to the TA.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a random access method, device and storage medium. Background Technology

[0002] In satellite communications, the distance between the satellite and the user equipment is very large, resulting in significant communication delays. If these delays are not pre-compensated, random access and normal communication will be impossible.

[0003] The shortcoming of existing technology is that it does not provide a solution for advancing the timing of user equipment calculations. Summary of the Invention

[0004] This invention provides a random access method, device, and storage medium for providing a scheme to advance the calculation timing of user equipment.

[0005] This invention provides the following technical solutions:

[0006] A random access method, comprising:

[0007] The UE receives a beam signal, which carries a beam coverage area number. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0008] The UE determines its location based on the beam coverage area number;

[0009] The UE determines the TA based on the location relationship between the area and the communication satellite, and the location relationship is obtained by the UE in advance;

[0010] The UE initiates random access on the PRACH using Preamble based on the TA at the RO agreed with the communication satellite.

[0011] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0012] In practice, the positional relationship is a mapping table between the reference line and the satellite-to-ground distance. The reference line is a series of concentric circular lines planned with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0013] In practice, there is a one-to-one correspondence between wave positions and reference lines, with the geometric center of any wave position being closest to the reference line.

[0014] In practice, this further includes planning reference lines and wave positions in one or a combination of the following ways:

[0015] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0016] Avoid a wave level crossing two or more circular reference lines;

[0017] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0018] In practice, the beam signal is a portion of one or a combination of the following signals:

[0019] PSS, SSS, PBCH.

[0020] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0021] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0022] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0023] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0024] The information bits in the MIB carry the beam coverage area number;

[0025] Use SIB to carry the beam coverage area number.

[0026] In practice, when the UE is powered on or when the beam position or beam group is reselected, the beam coverage area number carried in the beam signal is detected.

[0027] During implementation, it further includes:

[0028] When at least two beam coverage area numbers are detected, the beam coverage area number carried by the beam signal with the best signal quality is used as the beam coverage area number.

[0029] During implementation, it further includes:

[0030] Set TA = RTT_est - TA_margin, where RTT_est is the RTT determined based on the reference line, TA_margin is the protection margin for advance timing, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0031] In practice, the UE initiates random access on the PRACH using Preamble based on the TA at the RO agreed upon with the communication satellite, including:

[0032] The UE initiates random access after a time interval RO Shift-TA, based on the time when it receives the beam coverage area number, where RO Shift is agreed upon by the UE and the communication satellite.

[0033] In practice, when the Preamble arrives at the communication satellite, the deviation from the standard timing of the base station (communication satellite) is:

[0034] DTA=RTT_act-RTT_est+TA_margin

[0035] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0036] During implementation, it further includes:

[0037] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0038] During implementation, it further includes:

[0039] After receiving the timing deviation from the communication satellite, the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0040] A random access method, comprising:

[0041] The communication satellite sends a beam signal to the UE. The beam signal carries a beam coverage area number. The beam coverage area is the area covered on the ground by the beam sent by the communication satellite. Each beam coverage area has its own preset number.

[0042] The communication satellite receives the random access initiated by the UE on the PRACH using Preamble at the RO agreed with the communication satellite.

[0043] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0044] In practice, the beam signal is a portion of one or a combination of the following signals:

[0045] PSS, SSS, PBCH.

[0046] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0047] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0048] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0049] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0050] The information bits in the MIB carry the beam coverage area number;

[0051] Use SIB to carry the beam coverage area number.

[0052] During implementation, it further includes:

[0053] The UE is notified of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

[0054] In practice, the receiving UE initiates random access via Preamble on PRACH at the RO agreed upon with the communication satellite, including:

[0055] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0056] During implementation, it further includes:

[0057] Advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0058] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0059] During implementation, it further includes:

[0060] After detecting the timing deviation of the Preamble arrival, the timing deviation is fed back to the UE, and the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0061] A user equipment, comprising:

[0062] The processor is used to read programs from memory and execute the following procedures:

[0063] Receive beam signals, which carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0064] The UE's location is determined based on the beam coverage area number;

[0065] The TA is determined based on the location relationship between the area and the communication satellite, and the location relationship is obtained in advance by the UE;

[0066] According to the agreement between the TA and the communications satellite, random access is initiated on PRACH using Preamble at the RO.

[0067] A transceiver is used to receive and send data under the control of a processor.

[0068] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0069] In practice, the positional relationship is a mapping table between the reference line and the satellite-to-ground distance. The reference line is a series of concentric circular lines planned with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0070] In practice, there is a one-to-one correspondence between wave positions and reference lines, with the geometric center of any wave position being closest to the reference line.

[0071] In practice, this further includes planning reference lines and wave positions in one or a combination of the following ways:

[0072] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0073] Avoid a wave level crossing two or more circular reference lines;

[0074] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0075] In practice, the beam signal is a portion of one or a combination of the following signals:

[0076] PSS, SSS, PBCH.

[0077] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0078] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0079] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0080] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0081] The information bits in the MIB carry the beam coverage area number;

[0082] Use SIB to carry the beam coverage area number.

[0083] In practice, when the UE is powered on or when the beam position or beam group is reselected, the beam coverage area number carried in the beam signal is detected.

[0084] During implementation, it further includes:

[0085] When at least two beam coverage area numbers are detected, the beam coverage area number carried by the beam signal with the best signal quality is used as the beam coverage area number.

[0086] During implementation, it further includes:

[0087] Set TA = RTT_est - TA_margin, where RTT_est is the RTT determined based on the reference line, TA_margin is the protection margin for advance timing, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0088] In practice, according to the TA, random access is initiated on PRACH using Preamble at the RO agreed upon with the communication satellite, including:

[0089] Based on the time of receiving the beam coverage area number, random access is initiated after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0090] In practice, when the Preamble arrives at the communication satellite, the deviation from the standard timing of the base station (communication satellite) is:

[0091] DTA=RTT_act-RTT_est+TA_margin

[0092] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0093] During implementation, it further includes:

[0094] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0095] During implementation, it further includes:

[0096] After receiving the timing deviation from the communication satellite, the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0097] A user equipment, comprising:

[0098] The UE receiving module is used to receive beam signals, which carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0099] UE area module, used to determine the area where the UE is located based on the beam coverage area number;

[0100] The UE TA module is used to determine the TA based on the positional relationship between the area and the communication satellite, wherein the positional relationship is obtained in advance by the UE;

[0101] The UE access module is used to initiate random access on PRACH using Preamble based on the TA at the RO agreed with the communication satellite.

[0102] During implementation, it further includes:

[0103] The regional planning module is used to plan a region, wherein the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0104] In implementation, the regional planning module is further used to plan positional relationships, wherein the positional relationships are a mapping table of reference lines and satellite-to-ground distances. The reference lines are multiple concentric circular lines planned within the entire ground coverage area of ​​a communication satellite, centered on the nadir point. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0105] In practice, the regional planning module is further used to plan a one-to-one correspondence between wave position groups and reference lines, wherein the geometric center of any wave position is closest to the reference line.

[0106] In practice, the regional planning module is further used for reference line and wave position planning in one or a combination of the following ways:

[0107] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0108] Avoid a wave level crossing two or more circular reference lines;

[0109] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0110] In implementation, the UE receiving module is further configured to receive a portion of one or a combination of the following signals:

[0111] PSS, SSS, PBCH.

[0112] In implementation, the UE receiving module is further configured to receive the beam signal carrying the beam coverage area number through one or a combination of the following methods:

[0113] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0114] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0115] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0116] The information bits in the MIB carry the beam coverage area number;

[0117] Use SIB to carry the beam coverage area number.

[0118] In practice, the UE receiving module is further used to detect the beam coverage area number carried in the beam signal when the UE is powered on or when the beam position is reselected or the beam group is reselected.

[0119] In practice, the UE receiving module is further configured to, when detecting at least two beam coverage area numbers, use the beam coverage area number carried by the beam signal with the best signal quality as the beam coverage area number.

[0120] In implementation, the UE TA module is further used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, TA_margin is the protection margin for timing advance, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0121] In implementation, the UE access module is further used to initiate random access on PRACH using Preamble based on TA at RO agreed with the communication satellite, including:

[0122] The UE initiates random access after a time interval RO Shift-TA, based on the time when it receives the beam coverage area number, where RO Shift is agreed upon by the UE and the communication satellite.

[0123] In implementation, the UE access module is further used to determine the deviation between the Preamble and the standard timing of the communication satellite when the Preamble arrives at the communication satellite:

[0124] DTA=RTT_act-RTT_est+TA_margin

[0125] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0126] In practice, the regional planning module is further used to adjust the reference line and wave position group planning pattern, so that the reference line is closer to the inside of the wave position group, in order to reduce the RTT_est.

[0127] In practice, the UE receiving module further receives the timing deviation fed back by the communication satellite and uses the timing deviation as an adjustment amount for the timing advance of the UE's subsequent uplink transmission.

[0128] A communication satellite, comprising:

[0129] The processor is used to read programs from memory and execute the following procedures:

[0130] A beam signal is sent to the UE, the beam signal carrying a beam coverage area number. The beam coverage area is the area covered on the ground by the beam sent by the communication satellite, and each beam coverage area has its own preset number.

[0131] The UE receives random access initiated by Preamble on PRACH at the RO agreed with the communication satellite;

[0132] A transceiver is used to receive and send data under the control of a processor.

[0133] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0134] In practice, the beam signal is a portion of one or a combination of the following signals:

[0135] PSS, SSS, PBCH.

[0136] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0137] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0138] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0139] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0140] The information bits in the MIB carry the beam coverage area number;

[0141] Use SIB to carry the beam coverage area number.

[0142] During implementation, it further includes:

[0143] The UE is notified of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

[0144] In practice, the receiving UE initiates random access via Preamble on PRACH at the RO agreed upon with the communication satellite, including:

[0145] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0146] During implementation, it further includes:

[0147] Advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0148] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0149] During implementation, it further includes:

[0150] After detecting the timing deviation of the Preamble arrival, the timing deviation is fed back to the UE, and the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0151] A communication satellite, comprising:

[0152] The satellite transmission module is used to send beam signals to the UE. The beam signals carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite. Each beam coverage area has its own preset number.

[0153] The satellite receiving module is used to receive random access initiated by the UE on the PRACH using Preamble at the RO agreed with the communication satellite.

[0154] In practice, the regional planning module is further used to plan the beam coverage area, which is composed of a set of wave positions. The wave positions are multiple wave positions divided within the entire ground coverage area of ​​a communication satellite, centered on the nadir point. A beam covers one wave position at a certain time.

[0155] In practice, the satellite transmission module is further configured to transmit a portion of the beam signal, which is one or a combination of the following signals:

[0156] PSS, SSS, PBCH.

[0157] In practice, the satellite transmission module is further used to carry the beam signal with the beam coverage area number through one or a combination of the following methods:

[0158] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0159] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0160] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0161] The information bits in the MIB carry the beam coverage area number;

[0162] Use SIB to carry the beam coverage area number.

[0163] In practice, the satellite transmission module is further used to notify the UE of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

[0164] In implementation, the satellite receiving module is further used to receive random access initiated by the UE on PRACH using Preamble at the RO agreed with the communication satellite, including:

[0165] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0166] In implementation, the satellite receiving module is further used to advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0167] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0168] In practice, the satellite receiving module is further used to detect the timing deviation of the Preamble arrival, and then feeds the timing deviation back to the UE, using the timing deviation as an adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0169] A computer-readable storage medium storing a computer program that performs the above-described random access method.

[0170] The beneficial effects of this invention are as follows:

[0171] In the technical solution provided by the embodiments of the present invention, since the beam signal transmitted by the communication satellite carries the beam coverage area number, the UE can know its location. By pre-obtaining the positional relationship between the area and the communication satellite, such as the satellite-to-ground distance, the TA can be determined, and random access can be initiated based on the TA. Attached Figure Description

[0172] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0173] Figure 1 This is a schematic diagram illustrating the implementation process of the random access method on the UE side in an embodiment of the present invention;

[0174] Figure 2 This is a schematic diagram illustrating the implementation process of the random access method on the communication satellite side in an embodiment of the present invention;

[0175] Figure 3 This is a schematic diagram illustrating the relationship between satellites and wave positions in an embodiment of the present invention;

[0176] Figure 4 This is a schematic diagram of the circular reference line planning in an embodiment of the present invention;

[0177] Figure 5 This is a schematic diagram of wave position group planning in an embodiment of the present invention;

[0178] Figure 6 This is a schematic diagram illustrating the protection margin relationship for timing advance in an embodiment of the present invention;

[0179] Figure 7 This is a schematic diagram of the UE structure in an embodiment of the present invention;

[0180] Figure 8 This is a schematic diagram of the communication satellite structure in an embodiment of the present invention. Detailed Implementation

[0181] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0182] In this explanation, the implementation will be described separately from the perspectives of the UE and the communication satellite base station. Examples of their combined implementation will also be provided to better understand the implementation of the solutions presented in this embodiment. This explanation does not imply that the two must be implemented together or separately. In fact, when the UE and communication satellite are implemented separately, they each address the problems on the UE side and the communication satellite base station side respectively. However, combining the two will yield better technical results.

[0183] Figure 1 The figure shows a schematic diagram of the random access method implementation process on the UE side, including:

[0184] Step 101: The UE receives a beam signal, which carries a beam coverage area number. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0185] Step 102: The UE determines its location based on the beam coverage area number;

[0186] Step 103: The UE determines the TA based on the positional relationship between the area and the communication satellite, wherein the positional relationship is obtained in advance by the UE;

[0187] Step 104: The UE initiates random access on the PRACH using Preamble based on the TA at the RO agreed with the communication satellite.

[0188] Figure 2 The figure shows a schematic diagram of the implementation process of the random access method on the communication satellite side, including:

[0189] Step 201: The communication satellite sends a beam signal to the UE. The beam signal carries a beam coverage area number. The beam coverage area is the area covered on the ground by the beam sent by the communication satellite. Each beam coverage area has its own preset number.

[0190] Step 202: The communication satellite receives the random access initiated by the UE on the PRACH using Preamble at the RO agreed with the communication satellite.

[0191] The following section will explain the implementation of the wavelet planning scheme for satellite communication and the time synchronization pre-compensation scheme based on wavelet groups.

[0192] The beam coverage area will be specifically described using wave positions and wave position groups. Correspondingly, the beam coverage area number will be described using the wave position group number GID in the embodiment.

[0193] 1. Beam.

[0194] A communications satellite uses multiple beams to transmit its signals, covering its entire service area. These beams can operate simultaneously or in a time-division manner using scanning.

[0195] Satellite communication involves long wireless propagation distances and significant path loss, requiring high transmission power. However, since power consumption directly affects the overall cost of satellite design, production, and launch, transmission power is limited. The advantage of using multi-beam communication is that narrower beams result in higher beam gain, overcoming the problem of insufficient signal power at the receiving end caused by limited transmission power and high link loss. This is one of the important technical means for satellite communication, especially for small low-Earth orbit satellites.

[0196] 2. Wave position.

[0197] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0198] Specifically, Figure 3 This diagram illustrates the relationship between a satellite and its wavefronts. As shown, within the entire ground coverage area of ​​a communication satellite, multiple wavefronts are defined centered on the nadir point. The correspondence between wavefronts and beams is as follows: one beam covers one wavefront at a given time. The size and shape of each wavefront do not need to be identical.

[0199] 3. Reference lines.

[0200] In practice, the positional relationship is a mapping table between the reference line and the satellite-to-ground distance. The reference line is a series of concentric circular lines planned with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0201] Figure 4The diagram shows a schematic of the planning of circular reference lines. Within the entire ground coverage area of ​​a communication satellite, N concentric circular reference lines are planned with the nadir point as the center, denoted as C(i), i = 1, 2, ..., N.

[0202] The radius of C(i) is denoted as RC(i).

[0203] The geocentric angle of C(i) is denoted as AC(i), which represents the angle between any point on C(i) and the sub-satellite point relative to the geocenter.

[0204] The satellite-to-ground distance of C(i) is denoted as DC(i), which represents the distance between any point on C(i) and the communication satellite.

[0205] Once the reference line is established, it remains stable (unchanged until it is re-planned).

[0206] The UE (User Equipment) obtains the mapping table DC(i) between the reference line and the satellite-to-ground distance from the network in advance, where i = 1, 2, ..., N. Since the reference line and wavelet group planning is stable, this mapping table does not need to be updated frequently.

[0207] As an example, the circular reference lines C(i) are numbered in ascending order of their radius RC(i).

[0208] 4. Wave position group.

[0209] In practice, there is a one-to-one correspondence between wave positions and reference lines, with the geometric center of any wave position being closest to the reference line.

[0210] Figure 5 The diagram shows the planning of wave position groups, where the number marked in each wave position is its wave position group number. As shown in the figure, all wave positions are divided into N wave position groups, denoted as G(i), i = 1, 2, ..., N.

[0211] The number of wave positions contained in a wave position group G(i) is Ki. The number of wave positions in different wave position groups does not have to be equal. The k-th wave position in the wave position group G(i) is denoted as B(i,k), where i = 1, 2, ..., N and k = 1, 2, ..., Ki.

[0212] The position of the geometric centroid of B(i,k) is denoted as P(i,k). The distance between P(i,k) and the sub-star point is denoted as RP(i,k). The distance between P(i,k) and the circular reference line C(j) is denoted as DP(i,k,j).

[0213] DP(i,k,j)=abs[RP(i,k)-RC(j)]

[0214] Where i = 1, 2, ..., N, k = 1, 2, ..., Ki, j = 1, 2, ..., N, and abs is the absolute value.

[0215] Wave group planning methods can be:

[0216] The wave position group G(i) corresponds one-to-one with the reference line C(i), and the geometric center of any wave position is closest to the reference line C(i), that is:

[0217] DP(i,k,i)=min{DP(i,k,j),j=1,2,...N}, k=1,2,...,Ki

[0218] Through wavelet group planning, the various wavelets within the coverage area of ​​a communication satellite are roughly divided into multiple annular areas centered on a circular reference line.

[0219] This further includes planning reference lines and wave positions in one or a combination of the following ways:

[0220] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0221] Avoid a wave level crossing two or more circular reference lines;

[0222] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0223] Specifically, the optimization principles for reference lines and wave position planning can be implemented as follows:

[0224] (1) The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0225] The circular reference line should not be too sparse, otherwise some waveforms will be too far from their circular reference line, resulting in excessive RTT (Round Trip Time) and frequency offset estimation errors.

[0226] (2) Avoid a wave position crossing two or more circular reference lines;

[0227] Avoid crossing two or more circular reference lines unless absolutely necessary, otherwise it means that the circular reference lines are too dense, the number of wave groups is too large, and the utilization efficiency of wave group numbering is low.

[0228] (3) The sum of the distances from the geometric centroid of all wave positions in the wave position group to the reference line is the smallest.

[0229] If the wave position groups have been basically determined, and further optimization of the position of the circular reference line is needed, then an optimal solution is to minimize the sum of the distances from the geometric centroid of all wave positions in the wave position group to their reference line.

[0230] Once established, the prepositioning pattern remains stable, meaning it remains unchanged until re-planned. For GEO (Geostationary Earth Orbit), the communication satellite is stationary relative to the ground, and the prepositioning pattern is static and stable relative to the ground. For MEO (Medium Earth Orbit) and LEO (Low Earth Orbit), the prepositions move with the communication satellite relative to the ground, but the prepositioning pattern remains stable relative to the communication satellite.

[0231] 5. Transmission of wave group numbers.

[0232] In practice, the beam signal is a portion of one or a combination of the following signals:

[0233] PSS, SSS, PBCH.

[0234] Specifically, communication satellites can send the band position group number (GID) to the UE via beam signals.

[0235] When the beam points to a wave position B(i,k), i=1,2,...,N, k=1,2,...,Ki, the beam signal carries the wave position group number information GID=i for that wave position.

[0236] For 3GPP NTN (Non-Terrestrial Networks), or other communication systems derived from 4G LTE (4th Generation Long Term Evolution) or 5G NR (5th Generation New Radio), the beam signal can be part of the PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), or PBCH (Physical Broadcast Channel).

[0237] In specific implementation, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0238] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0239] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0240] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0241] The information bits in the MIB carry the beam coverage area number;

[0242] Use SIB to carry the beam coverage area number.

[0243] The following is an explanation.

[0244] Method 1:

[0245] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0246] The information bits originally transmitting CID (Physical Layer Cell Identity) in PSS and SSS can be reallocated, or expanded first and then reallocated, with a portion allocated to CID and another portion to GID. A trade-off can be made between the CID requirement for inter-cell interference avoidance and the GID requirement based on the planned number of beamgroups.

[0247] Method 2:

[0248] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0249] The information bits in the PBCH that originally transmitted the SSB index (SSB index; SSB: Synchronization Signal and PBCH block) are reallocated, or expanded first and then reallocated, and all or part of them are allocated to the GID.

[0250] It should be noted that in 5G NR, each SSB beam carries a different SSB index when it is transmitted within an SSB cycle. The difference in this scheme is that different beams in the same band carry the same GID.

[0251] Method 3:

[0252] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0253] The information bits in the MIB carry the beam coverage area number;

[0254] The information bits in the PBCH that originally transmitted additional timing-related PBCH payload bits and / or MIB (Master Information Block) are reallocated or expanded and then reallocated to achieve the purpose of carrying GID.

[0255] Method 4:

[0256] Use SIB to carry the beam coverage area number.

[0257] Use SIB (System Information Block) or other resources to transmit GID.

[0258] 6. Time synchronization pre-compensation based on wave group.

[0259] In practice, when the UE is powered on or when the beam position or beam group is reselected, the beam coverage area number carried in the beam signal is detected.

[0260] In specific implementation, when at least two beam coverage area numbers are detected, the beam coverage area number carried by the beam signal with the best signal quality is used as the beam coverage area number.

[0261] Specifically, when a UE powers on or during beam reselection or beam group reselection, it detects the GID in the received signal over a period of time, such as one beam scan cycle. If only one GID is detected, this GID is used as the UE's GID, denoted as UE_GID. If multiple GIDs are detected successively, the GID carried in the beam signal with the best signal quality is used as the UE_GID.

[0262] The purpose of UE_GID is to indicate the frequency group to which the UE is currently located. Since there is a one-to-one correspondence between frequency groups and circular reference lines, and each frequency group is surrounded by a circular reference line, UE_GID also indicates the reference line closest to the frequency of the UE, namely C(UE_GID).

[0263] Using DC(UE_GID) as an estimate of the satellite-to-ground distance for the UE, the estimated RTT of the UE can be calculated, as shown in the following formula:

[0264]

[0265] Where c represents the speed of light, which is a constant and approximately 3E8 meters per second.

[0266] In practice, it may further include:

[0267] Set TA = RTT_est - TA_margin, where RTT_est is the RTT determined based on the reference line, TA_margin is the protection margin for advance timing, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0268] Figure 6 The diagram illustrates the protection margin relationship for timing advance. The UE sets its timing advance value GTA (Timing Advance) as follows:

[0269] GTA = RTT_est - TA_margin

[0270] TA_margin (TA edge) is the protection margin for advance timing (TA_margin≥0), which can be set to half the detection window length, or other values ​​can be taken and notified to the UE by the network in advance.

[0271] In practice, for the UE side: the UE initiates random access on the PRACH using Preamble based on the TA at the RO agreed with the communication satellite, including:

[0272] The UE initiates random access after a time interval RO Shift-TA, based on the time when it receives the beam coverage area number, where RO Shift is agreed upon by the UE and the communication satellite.

[0273] Correspondingly, for the communication satellite side, this includes: receiving random access initiated by the UE using Preamble on PRACH at the RO agreed with the communication satellite, including:

[0274] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0275] Specifically, after the base station (communication satellite) sends a signal carrying a GID, it sets an access opportunity RO after a time interval RO Shift (RO offset; RO: access opportunity, RACH Opportunity; RACH: Random Access Channel).

[0276] The time interval RO Shift is agreed upon by the network side and the UE through a protocol.

[0277] The UE sends the Physical Random Access Channel (PRACH) after a time interval of RO Shift-GTA, based on the time when it receives the GID.

[0278] It should be noted that there can be multiple ROs and their RO Shifts corresponding to this GID. Here, only one available RO and its RO Shift are described. "Available" means that the condition RO Shift - GTA - Tother ≥ 0 is met, where Tother (the other one) includes reception and processing time, etc.

[0279] In practice, when the Preamble arrives at the communication satellite, the deviation from the standard timing of the base station (communication satellite) is:

[0280] DTA=RTT_act-RTT_est+TA_margin

[0281] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0282] Specifically, when PRACH arrives at the base station (communication satellite), the deviation from the base station's (communication satellite's) standard timing is:

[0283] DTA=RTT_act-RTT_est+TA_margin

[0284] RTT_act represents the UE's true (accurate) RTT. RTT_act - RTT_est may be positive or negative. Adding TA_margin can guarantee or with a high probability that DTA is positive, so that when the Preamble ((Random Access Channel) Preamble, (RACH)Preamble) arrives at the base station (communication satellite), its starting point falls within the detection window.

[0285] In specific implementation, for the UE side, it can further include:

[0286] After receiving the timing deviation from the communication satellite, the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0287] Correspondingly, for the communication satellite side: after detecting the timing deviation of the Preamble arrival, the timing deviation is fed back to the UE, and the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmission.

[0288] Specifically, after the base station (communication satellite) detects the timing deviation of the PRACH arrival (equal to DTA), it feeds this value back to the UE as an adjustment amount for the timing advance of the UE's subsequent uplink transmission, thereby achieving further uplink synchronization adjustment.

[0289] In practice, it may further include:

[0290] Advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0291] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0292] Another way to achieve protection margin 1:

[0293] like Figure 6 As shown, the following method can also be used to achieve the function of protecting the margin TA_margin.

[0294] The base station (communication satellite) advances the timing of the PRACH detection window by a margin, such as half the detection window length. The UE's TA pre-compensation value is set as follows:

[0295] GTA = RTT_est

[0296] The timing deviation of the PRACH signal from the standard timing of the base station (communication satellite) when it arrives is:

[0297] DTA = RTT_act - RTT_est

[0298] DTA can be positive or negative, and it can fall into the detection window.

[0299] The advantage of this approach is that TA_margin does not require network notification to the UE.

[0300] Another way to achieve protection margin 2:

[0301] To achieve the function of protecting the margin TA_margin, the following solution can also be adopted.

[0302] like Figure 5 As shown, the circular reference line C(1) shrinks to the sub-satellite point. Adjust the circular reference line and the wave position group planning pattern so that the circular reference line is close to the inner side of the wave position group, thereby reducing RTT_est. Set GTA = RTT_est, then DTA = RTT_act - RTT_est. DTA is a positive number, or is positive with a high probability.

[0303] Based on the same inventive concept, this invention also provides a communication satellite, user equipment, and computer-readable storage medium. Since the principles by which these devices solve the problem are similar to those of the random access method, the implementation of these devices can be referred to the implementation of the method, and repeated details will not be repeated.

[0304] When implementing the technical solutions provided in the embodiments of the present invention, they can be implemented in the following manner.

[0305] Figure 7 The figure shows a schematic diagram of the UE structure. The user equipment includes:

[0306] Processor 700 is used to read the program from memory 720 and execute the following procedures:

[0307] Receive beam signals, which carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0308] The UE's location is determined based on the beam coverage area number;

[0309] The TA is determined based on the location relationship between the area and the communication satellite, and the location relationship is obtained in advance by the UE;

[0310] According to the agreement between the TA and the communications satellite, random access is initiated on PRACH using Preamble at the RO.

[0311] Transceiver 710 is used to receive and send data under the control of processor 700.

[0312] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0313] In practice, the positional relationship is a mapping table between the reference line and the satellite-to-ground distance. The reference line is a series of concentric circular lines planned with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0314] In practice, there is a one-to-one correspondence between wave positions and reference lines, with the geometric center of any wave position being closest to the reference line.

[0315] In practice, this further includes planning reference lines and wave positions in one or a combination of the following ways:

[0316] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0317] Avoid a wave level crossing two or more circular reference lines;

[0318] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0319] In practice, the beam signal is a portion of one or a combination of the following signals:

[0320] PSS, SSS, PBCH.

[0321] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0322] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0323] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0324] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0325] The information bits in the MIB carry the beam coverage area number;

[0326] Use SIB to carry the beam coverage area number.

[0327] In practice, when the UE is powered on or when the beam position or beam group is reselected, the beam coverage area number carried in the beam signal is detected.

[0328] During implementation, it further includes:

[0329] When at least two beam coverage area numbers are detected, the beam coverage area number carried by the beam signal with the best signal quality is used as the beam coverage area number.

[0330] During implementation, it further includes:

[0331] Set TA = RTT_est - TA_margin, where RTT_est is the RTT determined based on the reference line, TA_margin is the protection margin for advance timing, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0332] In practice, according to the TA, random access is initiated on PRACH using Preamble at the RO agreed upon with the communication satellite, including:

[0333] Based on the time of receiving the beam coverage area number, random access is initiated after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0334] In practice, when the Preamble arrives at the communication satellite, the deviation from the standard timing of the base station (communication satellite) is:

[0335] DTA=RTT_act-RTT_est+TA_margin

[0336] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0337] During implementation, it further includes:

[0338] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0339] During implementation, it further includes:

[0340] After receiving the timing deviation from the communication satellite, the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0341] Among them, Figure 7 In this context, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits of one or more processors represented by processor 700 and memory represented by memory 720 together. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. The transceiver 710 can be multiple elements, including transmitters and receivers, providing a unit for communicating with various other devices over a transmission medium. For different user equipment, the user interface 730 can also be an interface capable of connecting external or internal devices, including but not limited to keypads, displays, speakers, microphones, joysticks, etc.

[0342] The processor 700 is responsible for managing the bus architecture and general processing, while the memory 720 can store the data used by the processor 700 during operation.

[0343] This invention also provides a user equipment, comprising:

[0344] The UE receiving module is used to receive beam signals, which carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite, and each beam coverage area has its own preset number.

[0345] UE area module, used to determine the area where the UE is located based on the beam coverage area number;

[0346] The UE TA module is used to determine the TA based on the positional relationship between the area and the communication satellite, wherein the positional relationship is obtained in advance by the UE;

[0347] The UE access module is used to initiate random access on PRACH using Preamble based on the TA at the RO agreed with the communication satellite.

[0348] During implementation, it further includes:

[0349] The regional planning module is used to plan a region, wherein the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0350] In implementation, the regional planning module is further used to plan positional relationships, wherein the positional relationships are a mapping table of reference lines and satellite-to-ground distances. The reference lines are multiple concentric circular lines planned within the entire ground coverage area of ​​a communication satellite, centered on the nadir point. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

[0351] In practice, the regional planning module is further used to plan a one-to-one correspondence between wave position groups and reference lines, wherein the geometric center of any wave position is closest to the reference line.

[0352] In practice, the regional planning module is further used for reference line and wave position planning in one or a combination of the following ways:

[0353] The number of reference lines is determined based on the RTT and frequency offset estimation error threshold requirements;

[0354] Avoid a wave level crossing two or more circular reference lines;

[0355] The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

[0356] In implementation, the UE receiving module is further configured to receive a portion of one or a combination of the following signals:

[0357] PSS, SSS, PBCH.

[0358] In implementation, the UE receiving module is further configured to receive the beam signal carrying the beam coverage area number through one or a combination of the following methods:

[0359] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0360] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0361] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0362] The information bits in the MIB carry the beam coverage area number;

[0363] Use SIB to carry the beam coverage area number.

[0364] In practice, the UE receiving module is further used to detect the beam coverage area number carried in the beam signal when the UE is powered on or when the beam position is reselected or the beam group is reselected.

[0365] In practice, the UE receiving module is further configured to, when detecting at least two beam coverage area numbers, use the beam coverage area number carried by the beam signal with the best signal quality as the beam coverage area number.

[0366] In implementation, the UE TA module is further used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, TA_margin is the protection margin for timing advance, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

[0367] In implementation, the UE access module is further used to initiate random access on PRACH using Preamble based on TA at RO agreed with the communication satellite, including:

[0368] The UE initiates random access after a time interval RO Shift-TA, based on the time when it receives the beam coverage area number, where RO Shift is agreed upon by the UE and the communication satellite.

[0369] In implementation, the UE access module is further used to determine the deviation between the Preamble's arrival at the communication satellite and the base station's (communication satellite's) standard timing:

[0370] DTA=RTT_act-RTT_est+TA_margin

[0371] Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

[0372] In practice, the regional planning module is further used to adjust the reference line and wave position group planning pattern, so that the reference line is closer to the inside of the wave position group, in order to reduce the RTT_est.

[0373] In practice, the UE receiving module further receives the timing deviation fed back by the communication satellite and uses the timing deviation as an adjustment amount for the timing advance of the UE's subsequent uplink transmission.

[0374] For ease of description, the various parts of the device described above are divided into modules or units according to their functions. Of course, in implementing this invention, the functions of each module or unit can be implemented in one or more software or hardware components.

[0375] Figure 8 This is a schematic diagram of a communication satellite structure. As shown in the figure, a communication satellite includes:

[0376] Processor 800 is used to read the program from memory 820 and execute the following procedures:

[0377] A beam signal is sent to the UE, the beam signal carrying a beam coverage area number. The beam coverage area is the area covered on the ground by the beam sent by the communication satellite, and each beam coverage area has its own preset number.

[0378] The UE receives random access initiated by Preamble on PRACH at the RO agreed with the communication satellite;

[0379] Transceiver 810 is used to receive and send data under the control of processor 800.

[0380] In practice, the beam coverage area is composed of a set of wave positions. The wave positions are multiple wave positions divided with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. A beam covers one wave position at a certain time.

[0381] In practice, the beam signal is a portion of one or a combination of the following signals:

[0382] PSS, SSS, PBCH.

[0383] In practice, the beam signal carries the beam coverage area number through one or a combination of the following methods:

[0384] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0385] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0386] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0387] The information bits in the MIB carry the beam coverage area number;

[0388] Use SIB to carry the beam coverage area number.

[0389] During implementation, it further includes:

[0390] The UE is notified of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

[0391] In practice, the receiving UE initiates random access via Preamble on PRACH at the RO agreed upon with the communication satellite, including:

[0392] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0393] During implementation, it further includes:

[0394] Advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0395] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0396] During implementation, it further includes:

[0397] After detecting the timing deviation of the Preamble arrival, the timing deviation is fed back to the UE, and the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0398] Among them, Figure 8In this context, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits together, represented by one or more processors (processor 800) and memory (memory 820). The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. The transceiver 810 can be multiple elements, including transmitters and receivers, providing a unit for communicating with various other devices over a transmission medium. The processor 800 is responsible for managing the bus architecture and general processing, and the memory 820 can store data used by the processor 800 during operation.

[0399] This invention also provides a communication satellite, comprising:

[0400] The satellite transmission module is used to send beam signals to the UE. The beam signals carry beam coverage area numbers. The beam coverage area is the area covered on the ground by the beam transmitted by the communication satellite. Each beam coverage area has its own preset number.

[0401] The satellite receiving module is used to receive random access initiated by the UE on the PRACH using Preamble at the RO agreed with the communication satellite.

[0402] In practice, the regional planning module is further used to plan the beam coverage area, which is composed of a set of wave positions. The wave positions are multiple wave positions divided within the entire ground coverage area of ​​a communication satellite, centered on the nadir point. A beam covers one wave position at a certain time.

[0403] In practice, the satellite transmission module is further configured to transmit a portion of the beam signal, which is one or a combination of the following signals:

[0404] PSS, SSS, PBCH.

[0405] In practice, the satellite transmission module is further used to carry the beam signal with the beam coverage area number through one or a combination of the following methods:

[0406] The portion of the CID transmitted in the PSS or SSS carries the beam coverage area number.

[0407] The portion of the SSB index transmitted in the PBCH carries the beam coverage area number.

[0408] The portion of the PBCH that transmits additional bits carries the beam coverage area number;

[0409] The information bits in the MIB carry the beam coverage area number;

[0410] Use SIB to carry the beam coverage area number.

[0411] In practice, the satellite transmission module is further used to notify the UE of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

[0412] In implementation, the satellite receiving module is further used to receive random access initiated by the UE on PRACH using Preamble at the RO agreed with the communication satellite, including:

[0413] The receiving UE initiates random access based on the time when it receives the beam coverage area number, after a time interval RO Shift-TA, where RO Shift is agreed upon by the UE and the communication satellite.

[0414] In implementation, the satellite receiving module is further used to advance the timing of the PRACH detection window by a margin TA_margin; and / or,

[0415] Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

[0416] In practice, the satellite receiving module is further used to detect the timing deviation of the Preamble arrival, and then feeds the timing deviation back to the UE, using the timing deviation as an adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

[0417] For ease of description, the various parts of the device described above are divided into modules or units according to their functions. Of course, in implementing this invention, the functions of each module or unit can be implemented in one or more software or hardware components.

[0418] This invention also provides a computer-readable storage medium storing a computer program that performs the above-described random access method.

[0419] For specific implementation details, please refer to the implementation of random access methods on the UE side and / or the communication satellite side.

[0420] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0421] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0422] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0423] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0424] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A random access method, characterized in that, include: User equipment (UE) receives a beam signal, which carries a beam position group number. The UE determines its location based on the wavelet group number; The UE determines the timing advance TA based on the positional relationship between the area and the communication satellite, and the positional relationship is obtained by the UE in advance; The UE initiates random access on the Physical Random Access Channel (PRACH) using a preamble sequence, based on the access timing (RO) agreed upon with the communication satellite by the TA. The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The UE initiates random access on PRACH using Preamble based on TA at RO agreed with the communication satellite, including: The UE initiates random access based on the time of receiving the wavelet group number, after a time interval RO Shift - TA, wherein the access timing offset RO Shift is agreed upon by the UE and the communication satellite.

2. The method as described in claim 1, characterized in that, The positional relationship is a mapping table of reference lines and satellite-to-ground distances. The reference lines are multiple concentric circular lines planned with the nadir point as the center within the entire ground coverage area of ​​a communication satellite. The satellite-to-ground distance is determined by the radius of the circular lines and the geocentric angle.

3. The method as described in claim 2, characterized in that, There is a one-to-one correspondence between wave positions and reference lines, and the geometric center of any wave position is closest to the reference line.

4. The method as described in claim 3, characterized in that, This further includes planning reference lines and wave positions in one or a combination of the following ways: The number of reference lines is determined based on the bidirectional transmission delay (RTT) and frequency offset estimation error threshold requirements; Avoid a wave level crossing two or more circular reference lines; The sum of the distances from the geometric centroids of all wave positions in the wave position group to the reference line is minimized.

5. The method as described in claim 1, characterized in that, The beam signal is a portion of one or a combination of the following signals: Primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH).

6. The method as described in claim 5, characterized in that, The beam signal carries the beam group number in one or a combination of the following ways: The portion of the Physical Cell Identifier (CID) transmitted in the PSS or SSS carries the wavelength group number. The portion of the synchronization signal block index (SSB index) transmitted in the PBCH carries the waveform group number. The portion of the additional bits transmitted in the PBCH carries the wavelet group number; The waveform group number is carried in part of the information bits of the main system information block (MIB); The System Information Block (SIB) carries the wave group number.

7. The method as described in claim 1, characterized in that, When the UE is powered on or when the beam position or beam group is reselected, the beam group number carried in the beam signal is detected.

8. The method as described in claim 7, characterized in that, Further includes: When at least two wavelet group numbers are detected, the wavelet group number carried by the beam signal with the best signal quality is used as the wavelet group number.

9. The method according to any one of claims 1 to 8, characterized in that, Further includes: Set TA = RTT_est - TA_margin, where RTT_est is the RTT determined based on the reference line, TA_margin is the protection margin for timing advance, and TA_margin is half the detection window length, or is notified to the UE in advance by the network.

10. The method as described in claim 1, characterized in that, When the Preamble arrives at the communication satellite, the deviation from the standard timing of the communication satellite is: DTA = RTT_act - RTT_est + TA_margin Among them, RTT_act represents the UE's actual RTT, RTT_est is the RTT determined based on the reference line, and TA_margin is the protection margin for timing advance.

11. The method as described in claim 10, characterized in that, Further includes: Adjust the reference line and wave group pattern so that the reference line is closer to the inside of the wave group, in order to reduce the size of RTT_est.

12. The method as described in claim 1, characterized in that, Further includes: After receiving the timing deviation from the communication satellite, the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

13. A random access method, characterized in that, include: The communication satellite sends a beam signal to the UE, and the beam signal carries a beam position group number; The communication satellite receives random access initiated by the UE on the PRACH using Preamble at the RO agreed with the communication satellite; The wave group number is used to determine the area where the UE is located, and the positional relationship between the area and the communication satellite is used to determine the timing advance (TA). The positional relationship is obtained by the UE in advance. The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The communication satellite receives random access initiated by the UE on PRACH using Preamble at the RO agreed upon with the communication satellite, including: The communication satellite receives a random access initiated by the UE based on the time when it receives the wavelet group number, after a time interval RO Shift - TA, where RO Shift is agreed upon by the UE and the communication satellite.

14. The method as described in claim 13, characterized in that, The beam signal is a portion of one or a combination of the following signals: PSS, SSS, PBCH.

15. The method as described in claim 14, characterized in that, The beam signal carries the beam group number in one or a combination of the following ways: The portion of the CID transmitted in the PSS or SSS carries the wavelength group number. The portion of the SSB index transmitted in the PBCH carries the wavelet group number; The portion of the additional bits transmitted in the PBCH carries the wavelet group number; The information bits in the MIB carry the wavelet group number; Use SIB to carry the wave group number.

16. The method as described in claim 13, characterized in that, Further includes: The UE is notified of TA_margin, which is used to set TA = RTT_est - TA_margin, where RTT_est is the RTT determined according to the reference line, and TA_margin is the protection margin for timing advance.

17. The method as described in claim 13, characterized in that, Further includes: Advance the timing of the PRACH detection window by a margin TA_margin; and / or, Adjust the reference line and wave position group planning pattern so that the reference line is closer to the inside of the wave position group, in order to reduce RTT_est, which is the RTT determined based on the reference line.

18. The method as described in claim 13, characterized in that, Further includes: After detecting the timing deviation of the Preamble arrival, the timing deviation is fed back to the UE, and the timing deviation is used as the adjustment amount for the timing advance of the UE's subsequent uplink transmissions.

19. A user equipment, characterized in that, include: The processor is used to read programs from memory and execute the following procedures: Receive beam signals, wherein the beam signals carry wave position group numbers; The region where the UE is located is determined based on the wave group number; The TA is determined based on the location relationship between the area and the communication satellite, and the location relationship is obtained in advance by the UE; According to the agreement between the TA and the communications satellite, random access is initiated on PRACH using Preamble at the RO. A transceiver is used to receive and send data under the control of a processor; The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The step of initiating random access on PRACH using Preamble based on TA at RO agreed with the communication satellite includes: Based on the time of receiving the wavelet group number, random access is initiated after a time interval RO Shift - TA, where the access timing offset RO Shift is agreed upon by the UE and the communication satellite.

20. A user equipment, characterized in that, include: The UE receiving module is used to receive beam signals, which carry wavelet group numbers. UE region module, used to determine the region where the UE is located based on the wavelet group number; The UE TA module is used to determine the TA based on the positional relationship between the area and the communication satellite, wherein the positional relationship is obtained in advance by the UE; The UE access module is used to initiate random access on PRACH using Preamble based on TA at RO agreed with the communication satellite; The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The UE access module is specifically used for: Based on the time of receiving the wavelet group number, random access is initiated after a time interval RO Shift - TA, where the access timing offset RO Shift is agreed upon by the UE and the communication satellite.

21. A communication satellite, characterized in that, include: The processor is used to read programs from memory and execute the following procedures: Send a beam signal to the UE, the beam signal carrying a beam position group number; The UE receives random access initiated by Preamble on PRACH at the RO agreed with the communication satellite; A transceiver is used to receive and send data under the control of a processor; The wave group number is used to determine the area where the UE is located, and the positional relationship between the area and the communication satellite is used to determine the timing advance (TA). The positional relationship is obtained by the UE in advance. The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The random access initiated by the receiving UE on PRACH using Preamble at the RO agreed with the communication satellite includes: The receiving UE initiates random access based on the time of receiving the wavelet group number, after a time interval RO Shift - TA, where RO Shift is agreed upon by the UE and the communication satellite.

22. A communication satellite, characterized in that, include: The satellite transmission module is used to send beam signals to the UE, the beam signals carrying wavelet group numbers; The satellite receiving module is used to receive random access initiated by the UE on PRACH using Preamble at the RO agreed with the communication satellite; The wave group number is used to determine the area where the UE is located, and the positional relationship between the area and the communication satellite is used to determine the timing advance (TA). The positional relationship is obtained by the UE in advance. The wave position group is a set of wave positions. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave positions divided with the nadir point as the center. A beam covers one wave position at a certain time. Multiple wave positions constitute a wave position group. Within the entire ground coverage area of ​​a communication satellite, there are multiple wave position groups. Different beams corresponding to the same wave position group carry the same wave position group number. The satellite receiving module is specifically used for: The receiving UE initiates random access based on the time of receiving the wavelet group number, after a time interval RO Shift - TA, where RO Shift is agreed upon by the UE and the communication satellite.

23. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that performs the method of any one of claims 1 to 18.

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