Random access method and device, storage medium, terminal, and base station

Abstract

A random access method and apparatus, storage medium, terminal, and base station, wherein the method includes: during a random access process, sending Msg1 to a network via a first uplink carrier, so that the network selects a first downlink carrier from multiple candidate downlink carriers for sending Msg2, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving Msg2 sent by the network via the first downlink carrier; determining a second uplink carrier, and sending Msg3 to the network via the second uplink carrier, so that the network determines a second downlink carrier for sending Msg4; and receiving Msg4 sent by the network via the second downlink carrier. Thus, the carrier switching problem during the random access process can be solved.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a random access method and device, a storage medium, a terminal, and a base station. Background Art

[0002] In non-terrestrial networks (NTNs), also known as satellite networks, a cell consists of multiple beams. Due to the rapid movement of satellites, user equipment (UE) requires frequent beam switching. Future IoT devices accessing satellite networks will require a beam management mechanism. However, current terrestrial IoT protocols, namely Narrowband Internet of Things (NB-IoT) and Enhanced Machine Type Communication (eMTC), do not support beam management.

[0003] However, in current communication systems, the random access process lasts a long time. Coupled with the rapid movement of satellites, the UE may experience beam switching (i.e., carrier switching) during random access. Current protocols cannot address beam switching during random access. Summary of the Invention

[0004] The technical problem solved by the present invention is how to solve the beam switching problem in the random access process.

[0005] To solve the above problem, an embodiment of the present invention provides a random access method, which includes: during the random access process, sending Msg1 to the network through a first uplink carrier, so that the network selects a first downlink carrier to send Msg2 from multiple candidate downlink carriers, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving the Msg2 sent by the network through the first downlink carrier; determining a second uplink carrier, and sending Msg3 to the network through the second uplink carrier, so that the network determines the second downlink carrier to send Msg4; receiving Msg4 sent by the network through the second downlink carrier.

[0006] Optionally, before sending Msg1 to the network via the first uplink carrier, the method further includes: determining whether carrier switching occurs after sending Msg1; if carrier switching occurs, indicating the first target carrier to the network when sending Msg1, so that the network determines the first downlink carrier based on the first target carrier.

[0007] Optionally, different preamble codes and / or ROs are associated with each downlink carrier, and the first target carrier and the first downlink carrier are the same carrier. Before indicating to the network that beam switching occurs when sending Msg1, the method also includes: obtaining the preamble code and / or RO associated with the first downlink carrier; indicating the first target carrier to the network when sending Msg1 so that the network determines the first downlink carrier based on the target carrier, including: sending the Msg1 to the network through the obtained preamble code and / or RO, so that the network determines the first downlink carrier based on the obtained preamble code and / or RO.

[0008] Optionally, the network configures the association relationship between each downlink carrier and different preamble codes and / or ROs through system broadcast information or RRC signaling.

[0009] Optionally, the first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, and different preamble codes and / or ROs are associated with different carrier groups. The indicating to the network that beam switching occurs when sending Msg1 includes: determining the preamble code and / or RO associated with the first target carrier; the indicating to the network that the first target carrier occurs when sending Msg1 includes: sending the Msg1 to the network through the determined preamble code and / or RO, so that the network determines the carrier group corresponding to the first target carrier according to the determined preamble code and / or RO, and uses one or more carriers in the determined carrier group as the first downlink carrier.

[0010] Optionally, the network configures the association relationship between each carrier group and different preamble codes and / or ROs through system broadcast information or RRC signaling.

[0011] Optionally, if the number of first downlink carriers exceeds one, receiving the Msg2 through the first downlink carrier includes: selecting a carrier from the first downlink carriers, and receiving the Msg2 through the selected carrier.

[0012] Optionally, the selecting a carrier from the first downlink carriers includes: selecting a carrier with the best signal quality from the first downlink carriers.

[0013] Optionally, the determining whether carrier switching occurs after sending Msg1 includes: predicting whether carrier switching occurs after sending Msg1 by measuring the candidate downlink carrier or according to satellite ephemeris information and current position information.

[0014] Optionally, the Msg2 is also used to indicate whether carrier switching occurs after sending Msg2 or after sending Msg3. After receiving the Msg2 sent by the network through the first downlink carrier, it also includes: determining whether carrier switching occurs after sending Msg2 or after sending Msg3 based on the Msg2; wherein, when carrier switching occurs after sending Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; when carrier switching occurs after sending Msg2, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

[0015] Optionally, if the Msg2 carries indication information of the second uplink carrier, the Msg2 indicates that carrier switching occurs after sending the Msg2, and determining the second uplink carrier includes: determining the second uplink carrier according to the indication information of the second uplink carrier.

[0016] Optionally, if the Msg2 carries indication information of the second downlink carrier, the Msg2 indicates that carrier switching is sent after sending Msg3, and after sending Msg3 through the second uplink carrier, it also includes: determining the second downlink carrier according to the indication information of the second downlink carrier.

[0017] Optionally, before sending Msg3 to the network through the second uplink carrier, it also includes: determining whether carrier switching occurs after sending Msg3; if carrier switching occurs, indicating the second target carrier to the network when sending Msg3, so that the network determines the second downlink carrier to send Msg4 based on the second target carrier.

[0018] Optionally, the second target carrier and the second downlink carrier are the same carrier, and the indication information of the second downlink carrier is carried in the Msg3, so that the network determines the second downlink carrier according to the indication information of the second downlink carrier.

[0019] An embodiment of the present invention also provides a random access method, which includes: during the random access process, sending Msg1 to the network through a first uplink carrier, so that the network selects a first downlink carrier to send Msg2 from multiple candidate downlink carriers, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving the Msg2 sent by the network through the first downlink carrier; determining a second uplink carrier, and sending Msg3 to the network through the second uplink carrier, so that the network determines the second downlink carrier to send Msg4; and receiving Msg4 sent by the network through the second downlink carrier.

[0020] Optionally, the UE indicates a first target carrier when sending Msg1, and selecting the first downlink carrier to send Msg2 from multiple candidate downlink carriers includes: determining the first downlink carrier according to the first target carrier.

[0021] Optionally, different preamble codes and / or ROs are associated with each downlink carrier, the first target carrier and the first downlink carrier are the same carrier, and after the receiving UE sends the Msg1 through the first uplink carrier, it also includes: determining the first downlink carrier based on the preamble code and / or RO for sending the Msg1.

[0022] Optionally, the method further includes: configuring, for the UE through system broadcast information or RRC signaling, an association relationship between each downlink carrier and different preamble codes and / or ROs.

[0023] Optionally, the first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, and different preamble codes and / or ROs are associated with different carrier groups. The first downlink carrier for sending Msg2 is selected from multiple candidate downlink carriers, including: determining the carrier group corresponding to the first target carrier based on the sent Msg1 preamble code and / or RO, and using one or more carriers in the determined carrier group as the first downlink carrier.

[0024] Optionally, the method further includes: configuring association relationships between each carrier group and different preamble codes and / or ROs through system broadcast information or RRC signaling.

[0025] Optionally, the Msg2 is also used to indicate whether carrier switching occurs after sending Msg2 or after sending Msg3; wherein, when carrier switching occurs after sending Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; when carrier switching occurs after sending Msg2, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

[0026] Optionally, if the Msg2 carries indication information of the second uplink carrier, the Msg2 indicates that carrier switching is sent after sending the Msg2, and the UE determines the second uplink carrier according to the indication information of the second uplink carrier.

[0027] Optionally, if the Msg2 carries indication information of the second downlink carrier, the Msg2 indicates that carrier switching occurs after sending Msg3, and the UE determines the second downlink carrier according to the indication information of the second downlink carrier.

[0028] Optionally, if the Msg3 indicates a second target carrier, after receiving the Msg3 sent by the UE through the second uplink carrier, the method further includes: determining a second downlink carrier for sending Msg4 according to the second target carrier.

[0029] Optionally, the second target carrier and the second downlink carrier are the same carrier, the Msg3 carries indication information of the second downlink carrier, and the determining the second downlink carrier to send Msg4 based on the second target carrier includes: determining the second downlink carrier based on the indication information of the second downlink carrier.

[0030] An embodiment of the present invention also provides a random access device, which includes: a Msg1 sending module, used to send Msg1 to the network through a first uplink carrier during the random access process, so that the network selects a first downlink carrier to send Msg2 from multiple candidate downlink carriers, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; a Msg2 receiving module, used to receive the Msg2 sent by the network through the first downlink carrier; a Msg3 sending module, used to determine a second uplink carrier, and send Msg3 to the network through the second uplink carrier, so that the network determines the second downlink carrier to send Msg4; a Msg4 receiving module, used to receive Msg4 sent by the network through the second downlink carrier.

[0031] An embodiment of the present invention also provides a random access device, which includes: a Msg1 receiving module, used to receive Msg1 sent by the UE through a first uplink carrier during a random access process; a Msg2 sending module, used to select a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, and send the Msg2 to the UE through the first downlink carrier, so that the UE determines a second uplink carrier, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; a Msg3 receiving module, used to receive Msg3 sent by the UE through the second uplink carrier; and a Msg4 sending module, used to determine the second downlink carrier for sending Msg4, and send the Msg4 to the UE through the second downlink carrier.

[0032] An embodiment of the present invention further provides a storage medium having a computer program stored thereon, wherein the computer program executes the steps of any one of the methods when executed by a processor.

[0033] An embodiment of the present invention further provides a terminal, comprising a memory and a processor, wherein the memory stores a computer program executable on the processor, and the processor executes the steps of any one of the methods when executing the computer program.

[0034] An embodiment of the present invention further provides a base station, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the steps of any one of the methods when running the computer program.

[0035] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0036] The random access method provided in an embodiment of the present invention supports adding a beam management mechanism during UE-initiated random access. Typically, a cell consists of multiple beams / beam groups, with different beams / beam groups corresponding to different carriers. This method performs beam management through carrier switching to address the issue of beam switching during random access. Furthermore, it can effectively alleviate limitations on UE-initiated random access in satellite systems, increase system capacity, and improve the success rate of UE random access.

[0037] Furthermore, if carrier switching occurs after the UE sends Msg1, the UE may inform the network through Msg1 so that the network adjusts the first downlink carrier for sending Msg2.

[0038] Furthermore, if carrier switching occurs after the network sends Msg2, or if carrier switching occurs after the UE sends Msg3, the network can indicate this to the UE via Msg2. Alternatively, the UE can also indicate to the network via Msg3 that carrier switching occurs after sending Msg3.

[0039] Furthermore, during the random access process, whenever a UE switches carriers, a corresponding carrier switching mechanism can be used to ensure that the UE and the network have consistent understanding of the carrier on which information is being transmitted, thereby improving the success rate of random access. Furthermore, the solution of the embodiments of the present invention ensures that the random access process of each UE is not restricted by carrier switching, thereby increasing system capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of cells and beams in an NTN scenario in the prior art;

[0041] Figure 2 A schematic diagram of a random access process in the prior art;

[0042] Figure 3 1 is a flow chart of a random access method according to an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of a first carrier switching according to an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of a second carrier switching according to an embodiment of the present invention;

[0045] Figure 6 Schematic diagram of a third carrier switching according to an embodiment of the present invention;

[0046] Figure 7 1 is a flow chart of another random access method according to an embodiment of the present invention;

[0047] Figure 8 Schematic diagram of the structure of a random access device according to an embodiment of the present invention;

[0048] Figure 9 FIG. 4 is a schematic structural diagram of another random access device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] Specifically, for the multi-carrier mechanism of Narrow Band Internet of Things (NB-IoT): Since the NB-IoT single-frequency cell has only 180 kHz bandwidth, in addition to the overhead of NPSS, NSSS and SIB, the remaining service channel capacity is very small. In order to support a large number of terminals, multiple frequency points are needed to increase network capacity. In addition to the anchor carrier (anchor carrier) containing NPSS, NSSS and NPBCH, the cell can also contain several non-anchor carriers (non-anchor carriers) that do not contain NPSS, NSSS and NPBCH. A cell includes one anchor carrier and several non-anchor carriers. The spectrum bandwidth of each carrier is 180 kHz, and the maximum spectrum span of all carriers in the cell does not exceed 20 MHz.

[0050] Anchor carrier: In a multi-carrier cell, there is only one downlink carrier that supports the simultaneous transmission of the narrowband primary synchronization signal (NPSS), narrowband secondary synchronization signal (NSSS), narrowband physical broadcast channel (NPBCH), narrowband physical downlink control channel (NPDCCH), and narrowband physical downlink shared channel (NPDSCH). UEs on the anchor carrier need to monitor NPSS, NSSS, NPBCH, NPDCCH, and NPDSCH information.

[0051] Non-anchor carrier: A multi-carrier cell can have several downlink carriers that only carry NPDCCH and NPDSCH, but not NPSS, NSSS and NPBCH channels. UE can transmit data on non-anchor carriers. In addition, before the UE enters the connected state, the network will send a message through Msg4 (please refer to the Figure 2 The random access procedure in the UE specifies a carrier for subsequent downlink data transmission. In the idle state, the UE can monitor paging on non-anchor carriers.

[0052] See Figure 1 , Figure 1 This figure illustrates cells and beams in an existing NTN scenario. In an NTN scenario, a cell consists of multiple beams. Due to the rapid movement of satellites, UEs must frequently switch beams. Future IoT devices accessing satellite networks will require a beam management mechanism (current terrestrial IoT protocols, such as NB-IoT and eMTC, do not support beam management). Currently, the most common beam management method is carrier switching. Specifically, a cell consists of multiple beams, with different beams corresponding to different carriers. Carrier switching enables beam switching.

[0053] To ensure coverage, NB-IoT / eMTC uses repeated transmission technology. The maximum number of downlink transmission repetitions is defined as 2048, and the maximum number of uplink transmission repetitions is defined as 128. The actual number of PDSCH / PUSCH repetitions is dynamically indicated by the corresponding scheduling DCI using a specific bit field. The UE can determine the number of PDSCH / PUSCH repetitions based on the DCI. The maximum number of PDCCH repetitions (i.e., Rmax) is semi-statically configured by the Radio Resource Control (RRC) / System Information Block (SIB).

[0054] The NB-IOT random access (RA) process consists of four steps: message 1 (Msg1), message 2 (Msg2), message 3 (Msg3), and message 4 (Msg4). Figure 2 , Figure 2 This is a schematic diagram of a random access process in the prior art.

[0055] The step corresponding to Msg1 is that the UE sends a preamble (RACH preamble). Currently, the maximum number of retransmissions of Msg1 is 128. Before sending Msg1, the UE will obtain the current cell signal through the narrowband reference signal (NRS) (the cell signal can be represented by the quality reference signal received power (RSRP)). The UE compares the measured current cell signal (RSRP value) with the relevant threshold value configured by the network to determine the current coverage level (CE Level). Different CE Levels correspond to different numbers of Msg1 retransmissions. The UE can determine the number of retransmissions of Msg1 based on the determined CE Level. If the first attempt to send Msg1 fails, the terminal will upgrade the CE Level (i.e., increase the number of retransmissions of Msg1) and try again until it successfully receives Msg2 or exhausts the number of Msg1 retransmissions (or PRACH resources) corresponding to all CE Levels.

[0056] When the base station receives Msg1, it will instruct the UE to send the resources and related parameters of Msg3 (including subcarrier indication, number of Msg3 repetition transmissions, Modulation and Coding Scheme (MCS) indication, etc.) through the Msg2 Random Access Response message (RAR). Among them, the RAR of Msg2 is scheduled by DCI. When the UE receives Msg2, it first receives the DCI (the DCI is scrambled by RA-RNTI, and the DCI indicates the transmission parameters of Msg2-RAR (including the receiving resource location, subcarrier indication, number of Msg3 repetition transmissions, MCS indication, etc.)), and then receives Msg2-RAR based on the DCI. Msg2 can carry the time advance (TA), power correction (PowerCorrection), uplink (UL) grant (grant), temporary cell-radio network temporary identifier (TC-RNTI), etc.

[0057] The UE sends Msg3 based on the scheduling information for Msg3 indicated by Msg2-RAR. After sending Msg3, the UE uses the unique identifier carried in Msg3 to monitor the PDCCH. After successfully decoding the PDCCH, the UE receives the corresponding Msg4 content based on the DCI information carried by the PDCCH. Msg4 is scheduled by DCI. Msg3 includes an RRC connection request, and Msg4 includes contention resolution.

[0058] As mentioned in the background art, existing technologies cannot solve the beam switching problem during random access. Beam switching is when a UE switches from one beam / beam group to another beam / beam group.

[0059] To address the above-mentioned issues, an embodiment of the present invention provides a random access method, comprising: during a random access process, sending Msg1 to a network via a first uplink carrier, so that the network selects a first downlink carrier from multiple candidate downlink carriers for sending Msg2, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving Msg2 sent by the network via the first downlink carrier; determining a second uplink carrier, and sending Msg3 to the network via the second uplink carrier, so that the network determines a second downlink carrier for sending Msg4; and receiving Msg4 sent by the network via the second downlink carrier. This solves the problem of beam switching occurring during random access.

[0060] To make the above-mentioned objects, features, and beneficial effects of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be noted that in this embodiment of the present invention, different beams / beam groups correspond to different carriers / carrier sets, and beam switching is achieved through carrier switching.

[0061] See Figure 3 , Figure 3 2 is a flow chart of a random access method according to an embodiment of the present invention. The random access method may specifically include the following steps:

[0062] Step S301: During a random access process, Msg1 is sent to a network via a first uplink carrier, so that the network selects a first downlink carrier for sending Msg2 from a plurality of candidate downlink carriers, wherein the plurality of candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the plurality of candidate downlink carriers.

[0063] Step S302: receiving the Msg2 sent by the network through the first downlink carrier;

[0064] Among them, the first uplink carrier is the uplink carrier through which the UE sends Msg1 to the network. The first downlink carrier is the downlink carrier through which the network sends Msg2 to the UE based on the received Msg1. The first uplink carrier and the first downlink carrier can belong to the same beam / beam group or different beams / beam groups. Optionally, when the UE performs carrier switching after sending Msg1, the first downlink carrier and the first uplink carrier belong to different beams / beam groups; conversely, when the UE does not perform beam switching after sending Msg1, the first downlink carrier and the first uplink carrier belong to the same beam / beam group.

[0065] Figure 3 The method described is performed by the user equipment (UE), please refer to Figure 2In the random access process, after receiving Msg1 sent by the UE, the network does not directly send Msg2 to the UE based on the beam / beam group to which the first uplink carrier belongs. Instead, it selects the first downlink carrier from multiple candidate carriers belonging to different beams / beam groups.

[0066] Step S303: Determine a second uplink carrier, and send Msg3 to the network via the second uplink carrier, so that the network determines a second downlink carrier for sending Msg4;

[0067] Step S304: Receive Msg4 sent by the network through the second downlink carrier.

[0068] Among them, the second uplink carrier is the uplink carrier through which the UE sends Msg3 to the network, and the second downlink carrier is the downlink carrier through which the network sends Msg4 to the UE based on the received Msg3. The second uplink carrier and the second downlink carrier may also belong to the same or different beams / beam groups. Optionally, after sending Msg2, if carrier switching occurs, the UE may also send Msg2 through the second uplink carrier that belongs to a different beam / beam group from the first downlink carrier. The first uplink carrier is associated with multiple downlink carriers. If carrier switching occurs in the UE after sending Msg1, the UE may select other uplink carriers associated with the first downlink carrier as the first downlink carrier.

[0069] During the random access process, usually only one carrier switching may occur. If carrier switching occurs after Msg1 is sent, the network can select a carrier belonging to a different beam / beam group as the first downlink carrier according to step S301, and the first downlink carrier and the designated uplink carrier (i.e., the second uplink carrier) correspond to the correspondence between the first uplink carrier and multiple candidate downlink carriers, and the correspondence between the first downlink carrier and the designated uplink carrier can be configured by the network side through RRC signaling or system broadcast messages. Other opportunities for carrier switching are described in detail in the following embodiments.

[0070] Figure 3 The method described supports adding a beam management mechanism during UE-initiated random access. Typically, a cell consists of multiple beams / beam groups, with different beams / beam groups corresponding to different carriers. This method implements beam management through carrier switching to address beam switching issues during random access. Furthermore, it effectively alleviates limitations on UE-initiated random access in satellite systems, increases system capacity, and improves the success rate of UE random access.

[0071] In one embodiment, Figure 3Before sending Msg1 to the network through the first uplink carrier in step S301, it also includes: determining whether carrier switching occurs after sending Msg1, and if carrier switching occurs, indicating the first target carrier to the network when sending Msg1, so that the network determines the first downlink carrier according to the first target carrier.

[0072] Before the UE initiates random access, i.e., before sending Msg1, it can first determine whether carrier switching occurs after sending Msg1, so as to prepare for carrier switching after sending Msg1 and receive Msg2 on the corresponding carrier after switching (i.e., the first downlink carrier) to continue the random access process.

[0073] Optionally, the determining whether carrier switching occurs after sending Msg1 includes: predicting whether carrier switching occurs after sending Msg1 by measuring the candidate downlink carrier or according to satellite ephemeris information and current position information.

[0074] Specifically, the UE obtains the signal quality of each candidate downlink carrier based on the measurement results of each candidate downlink carrier. If the signal quality of a downlink carrier belonging to the same beam or beam group as the first uplink carrier is lower than a preset value, beam switching is determined to occur. Otherwise, beam switching does not occur. The UE thus determines whether carrier switching will occur after sending Msg1.

[0075] Alternatively, the UE can determine the satellite's trajectory based on the satellite ephemeris information and determine whether beam switching will occur due to the satellite's trajectory within a period of time after sending Msg1 based on the UE's current geographical location (i.e., current location information). Thus, the UE determines whether carrier switching will occur after sending Msg1.

[0076] It should be noted that the manner in which the UE determines whether to initiate a carrier switch (i.e., beam switch) after sending Msg1 includes but is not limited to the above-mentioned manner, and other manners may also be used. For example, the UE may determine whether to initiate a carrier switch after sending Msg1 based on its own needs or based on network instructions.

[0077] When the UE determines that carrier switching occurs after sending Msg1, the UE may indicate to the network a downlink carrier that belongs to a different beam / beam group than the first uplink carrier, i.e., the first target carrier. Optionally, the first target carrier may correspond to one or more downlink carriers. If the first target carrier corresponds to multiple downlink carriers, the multiple downlink carriers constitute a carrier group.

[0078] Optionally, if the UE determines that no carrier switching occurs after sending Msg1, the UE may not indicate the first target carrier, and the UE and the network side transmit Msg2 according to the existing solution.

[0079] In this embodiment, when carrier switching occurs after the UE side determines to send Msg1, the network is informed by indicating the first target carrier, so that the network side can determine the first downlink carrier for sending Msg2 according to the first target carrier.

[0080] In one embodiment, different preamble codes and / or ROs are associated with each downlink carrier, and the first target carrier and the first downlink carrier are the same carrier. Before indicating to the network that beam switching occurs when sending Msg1, it also includes: obtaining the preamble code and / or RO associated with the first downlink carrier; indicating the first target carrier to the network when sending Msg1 so that the network determines the first downlink carrier based on the target carrier, includes: sending the Msg1 to the network through the obtained preamble code and / or RO, so that the network determines the first downlink carrier based on the obtained preamble code and / or RO.

[0081] In this embodiment, the first target carrier corresponds to a single downlink carrier, that is, when sending Msg1, the UE directly indicates to the network the first downlink carrier for sending Msg2 after carrier switching.

[0082] Please see again Figure 2 , during the random access process, the UE sends a preamble (Preamble) of random access (RACH) in Msg1. The UE can indicate the first target carrier to the network through the preamble and / or the physical random access channel occasion (RACH Occasion, RO for short) sent by Msg1. Therein, it is pre-defined that there is an association relationship between different preambles and different downlink carriers, and the UE indicates different downlink carriers to the network through different preambles, and the downlink carriers indicated by them are the first target carrier. Alternatively, it is pre-defined that there is an association relationship between different ROs and different downlink carriers, and the UE indicates different downlink carriers to the network through different ROs, and the downlink carriers indicated by them are the first target carrier. Alternatively, it is pre-defined that there is an association relationship between different combinations of preambles and ROs and different downlink carriers, and the UE indicates different downlink carriers to the network through different combinations of preambles and ROs, and the downlink carriers indicated by them are the first target carrier.

[0083] Optionally, the network configures the association relationship between each downlink carrier and different preamble codes and / or ROs through system broadcast information or RRC signaling.

[0084] That is, the pre-defined association relationship between different preamble codes and different downlink carriers, or the association relationship between different ROs and different downlink carriers, or the association relationship between different combinations of preamble codes and ROs and different downlink carriers is configured for the UE by the network through system broadcast messages (such as SIB, etc.) or RRC signaling.

[0085] In a specific example, for the scenario of satellite Internet of Things, if it is considered that carrier switching may occur after sending Msg1, the network configures the association relationship between the first uplink carrier and the downlink carrier through system broadcast information or RRC dedicated signaling. Each first uplink carrier is associated with multiple candidate downlink carriers, and the multiple candidate downlink carriers correspond to different beams / beam groups. Secondly, the network also needs to configure the preamble code and / or RO corresponding to each candidate downlink carrier through system broadcast information or RRC dedicated signaling, that is, the multiple candidate downlink carriers are respectively associated with different preamble codes and / or different ROs. The network also needs to configure the uplink carrier associated with each candidate downlink carrier (that is, the carrier that sends Msg3) through system broadcast information or RRC dedicated signaling, that is, the downlink carriers are respectively associated with an uplink carrier. Further, the network configures the index of the uplink carrier associated with the downlink carrier.

[0086] The UE determines the above-mentioned carrier association relationship and the association relationship between the downlink carrier and the preamble code and / or RO by receiving system broadcast information or RRC dedicated signaling. Before sending Msg1, the UE predicts whether carrier switching will occur after sending Msg1 and determines the carrier after switching by measuring the candidate downlink carrier or based on the satellite ephemeris information and position information. When sending Msg1, the UE selects a specific preamble code and / or RO to send Msg1 based on the prediction result and the determined carrier after switching. When receiving Msg1, the network determines on which downlink carrier to send Msg2 based on the preamble code and / or RO selected by the UE. The UE determines the uplink carrier used to send Msg3 based on the number of the uplink carrier associated with Msg2, and the receiving carrier of Msg4 is the same carrier as the receiving carrier of Msg2.

[0087] See Figure 4 , Figure 4 This is a schematic diagram of the first carrier switching of an embodiment of the present invention. Assume that the downlink carriers associated with the uplink carrier U1 are: {D1, D2, D3}, wherein the uplink carrier associated with the downlink carrier D1 is associated with the uplink carrier U1, the downlink carrier D2 is associated with the uplink carrier U2, and the downlink carrier D3 is associated with the uplink carrier U3. beam1, beam2 and beam3 are three different groups of beams / beam groups, U1 / D1 is the carrier corresponding to beam1, U2 and D2 are the carriers corresponding to beam2, and U3 and D3 are the carriers corresponding to beam3. The preamble code and / or RO on the uplink carrier U1 is divided into three groups. The first group of preamble codes and / or RO corresponds to the downlink carrier D1 (i.e., no carrier switching occurs), the second group of preamble codes and / or RO corresponds to the downlink carrier D2 (i.e., carrier switching occurs), and the third group of preamble codes and / or RO corresponds to the downlink carrier D3 (i.e., carrier switching occurs). As Figure 4, the satellite moves rapidly to the left, and the sending positions of Msg1, Msg2, Msg3 and Msg4 are as follows Figure 4 As shown, carrier U1 is selected in the coverage area of beam1 to send Msg1, and carrier switching is predicted and the beam / beam group for the target switching is determined to be beam2. Then, the UE selects the downlink carrier D2 corresponding to the preamble and / or RO to send Msg1. When the network receives Msg1, it determines which downlink carrier to send Msg2 based on the preamble and / or RO selected by the UE (the receiving carrier of Msg2 is associated with the preamble and / or RO), that is, the base station sends Msg2 on carrier D2. The UE determines the uplink carrier for sending Msg3 based on the number of the uplink carrier associated with Msg2, that is, carrier U2 is the uplink carrier for sending Msg3. The receiving carrier of Msg4 is the same carrier as the receiving carrier of Msg2, that is, downlink carrier D2.

[0088] In one embodiment, the first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, and there is an association relationship between different preamble codes and / or ROs and different carrier groups. The indicating to the network that beam switching occurs when sending Msg1 includes: determining the preamble code and / or RO associated with the first target carrier; the indicating to the network that the first target carrier occurs when sending Msg1 includes: sending the Msg1 to the network through the determined preamble code and / or RO, so that the network determines the carrier group corresponding to the first target carrier according to the determined preamble code and / or RO, and uses one or more carriers in the determined carrier group as the first downlink carrier.

[0089] In this embodiment, the first target carrier corresponds to multiple downlink carriers, which form a carrier group. This means that when the UE sends Msg1, it indicates to the network a carrier group to be used for sending Msg2 after carrier switching. Based on transmission requirements, the network may select one or more downlink carriers from the carrier group corresponding to the first target carrier as the first downlink carrier. Optionally, the UE indicates the first target carrier, i.e., a carrier group, to the network via a preamble and / or RO.

[0090] Optionally, the network configures the association between each carrier group and different preambles and / or ROs through system broadcast information or RRC signaling. The association between the preamble and / or RO and the carrier group and the configuration of the association can be found in the description of the association between the preamble and / or RO and the downlink carrier in the previous embodiment, which will not be repeated here.

[0091] Optionally, if the number of first downlink carriers exceeds one, receiving the Msg2 through the first downlink carrier includes: selecting a carrier from the first downlink carriers, and receiving the Msg2 through the selected carrier.

[0092] As described above, when the first target carrier is a carrier group, the network may select one or more of the carrier groups as the first downlink carrier. For example, the network may select all downlink carriers in the carrier group as the first downlink carrier. In this case, there are more than one first downlink carriers, and the UE may select one downlink carrier from among them to receive Msg2.

[0093] Optionally, the selecting a carrier from the first downlink carriers includes: selecting a carrier with the best signal quality from the first downlink carriers. That is, the UE selects the carrier with the best signal quality from the first downlink carriers to receive Msg2.

[0094] In a specific example, for the scenario of satellite Internet of Things, if the possibility of carrier switching after sending Msg1 is considered, the network configures the association relationship between the first uplink carrier and the downlink carrier through system broadcast information or RRC dedicated signaling, that is, each first uplink carrier is associated with multiple candidate downlink carriers, and the multiple candidate downlink carriers correspond to different beams / beam groups. Secondly, the network also needs to configure the preamble code and / or RO corresponding to the occurrence of carrier switching and the non-occurrence of carrier switching through system broadcast information or RRC dedicated signaling. Further, the network configures two groups of preamble codes and / or ROs, one group of preamble codes and / or ROs is used to indicate to the network that no carrier switching occurs, and the other group of preamble codes and / or ROs is used to indicate to the network that beam switching occurs. Each group of preamble codes and / or ROs corresponds to a carrier group, and each carrier group includes multiple downlink carriers. At this time, there is a correspondence between the first group of preamble codes and / or RO and the carrier group composed of downlink carriers included in the current beam / beam group (the beam / beam group corresponding to when Msg1 is sent); there is a correspondence between the first group of preamble codes and / or RO and the carrier group composed of other downlink carriers in the candidate downlink carriers except the current beam / beam group. The network also needs to configure the uplink carrier associated with each candidate downlink carrier (i.e., the carrier that sends Msg3) through system broadcast information or RRC dedicated signaling, that is, each candidate downlink carrier is associated with an uplink carrier. Further, the network configures the index of the uplink carrier associated with the downlink carrier.

[0095] The UE determines the above-mentioned carrier association relationship and the association relationship between the downlink carrier and the preamble code and / or RO by receiving system broadcast information or RRC dedicated signaling. Before sending Msg1, the UE predicts whether beam switching (i.e., carrier switching) will occur after sending Msg1 by measuring the candidate downlink carrier or based on the satellite ephemeris information and position information. When sending Msg1, the UE selects a specific preamble code and / or RO to send Msg1 based on the prediction result. When receiving Msg1, the network determines whether beam switching occurs based on the preamble code and / or RO selected by the UE. If beam switching occurs in the UE, the network needs to send Msg2 on all candidate carriers except the downlink candidate carrier corresponding to the current beam / beam group.

[0096] After sending Msg1, the UE selects a specific downlink carrier (e.g., a downlink carrier with good signal quality) from among the candidate downlink carriers as the receiving carrier for Msg2 based on measurements of the candidate downlink carriers or based on satellite ephemeris information and location information. The UE determines the uplink carrier for sending Msg3 based on the uplink carrier associated with Msg2. The receiving carrier for Msg4 is the same carrier as the receiving carrier for Msg2.

[0097] Please see again Figure 4 , the network configures two groups of preambles and / or ROs, the first group of preambles and / or ROs is used to instruct the network not to switch beams, and the second group of preambles and / or ROs is used to instruct the network to switch beams. Figure 4 , the satellite moves quickly to the left, and the UE selects carrier U1 in the coverage area of beam 1 (beam1) to send Msg1, and determines to switch to beam 2 (beam2) based on the prediction results, then the UE selects the second group of preamble codes and / or RO to send Msg1, and determines D2 as the receiving carrier for Msg2. When receiving Msg1, the network determines that the UE has undergone beam switching based on the preamble code and / or RO selected by the UE, and sends Msg2 on all candidate downlink carriers (i.e., D2, D3 carriers) except the downlink candidate carrier corresponding to the current beam / beam group. In addition, the UE determines the uplink carrier for sending Msg3 based on the uplink carrier associated with the receiving carrier of Msg2 (i.e., D2), that is, carrier U2 is the uplink carrier for sending Msg3. The receiving carrier of Msg4 is the same carrier as the receiving carrier of Msg2, i.e., downlink carrier D2.

[0098] In another specific embodiment, for the scenario of satellite Internet of Things, if it is considered that carrier switching may occur after sending Msg1, the network configures the association relationship between the first uplink carrier and the downlink carrier through system broadcast information or RRC dedicated signaling, that is, each first uplink carrier is associated with multiple candidate downlink carriers, and the multiple candidate downlink carriers correspond to different beams / beam groups. The network also needs to configure the uplink carrier associated with each candidate downlink carrier (that is, the carrier that sends Msg3) through system broadcast information or RRC dedicated signaling, that is, each candidate downlink carrier is associated with an uplink carrier. Further, the network configures the index of the uplink carrier associated with the downlink carrier.

[0099] The UE determines the above-mentioned carrier association relationship and downlink carrier by receiving system broadcast information or RRC dedicated signaling. Before sending Msg1, the UE predicts whether beam switching (i.e., carrier switching) will occur after sending Msg1 by measuring the candidate downlink carrier or according to the satellite ephemeris information and position information, and determines the carrier after switching. After sending Msg1, the UE selects a specific downlink carrier (such as a downlink carrier with good signal quality) from the candidate downlink carriers as the Msg2 receiving carrier based on the prediction result (and the determined carrier after switching). For the network side, when the network receives Msg1, it will send Msg2 on all candidate carriers associated with the uplink carrier selected by the UE according to the uplink carrier selected by the UE. The UE determines the uplink carrier used to send Msg3 based on the uplink carrier associated with the Msg2 receiving carrier. The receiving carrier of Msg4 is the same carrier as the receiving carrier of Msg2.

[0100] Please see again Figure 4 , the satellite moves quickly to the left. The UE selects carrier U1 in the coverage area of beam1 to send Msg1, and determines that the beam / beam group after switching is beam2 based on the prediction results. Then the UE selects downlink carrier D2 to receive Msg2. For the network side, after receiving Msg1, the network will send Msg2 on all candidate downlink carriers associated with uplink carrier U1 (i.e., D1, D2, and D3). The UE determines the uplink carrier for sending Msg3 based on the uplink carrier associated with the carrier receiving Msg2, that is, carrier U2 is the uplink carrier for sending Msg3. The receiving carrier of Msg4 is the same carrier as the receiving carrier of Msg2, that is, downlink carrier D2.

[0101] In the above embodiment, if carrier switching occurs after the UE sends Msg1, the UE may inform the network through Msg1 so that the network adjusts the first downlink carrier for sending Msg2.

[0102] In one embodiment, the Msg2 is also used to indicate whether carrier switching occurs after sending Msg2 or after sending Msg3. Please refer to Figure 3 , Figure 3 After receiving the Msg2 sent by the network through the first downlink carrier in step S302, the method further includes: determining, based on the Msg2, whether carrier switching occurs after sending the Msg2 or after sending the Msg3; wherein, when carrier switching occurs after sending the Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; when carrier switching occurs after sending the Msg2, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

[0103] If the UE performs carrier switching after sending Msg2, the UE can select another uplink carrier associated with the first downlink carrier as the second uplink carrier. If carrier switching is considered after sending Msg2 or Msg3, the first downlink carrier can be associated with multiple corresponding uplink carriers, and these uplink carriers belong to different beams / beam groups; or the second uplink carrier can be associated with multiple corresponding downlink carriers, and these downlink carriers belong to different beams / beam groups. In this way, carrier switching requirements can be met.

[0104] In addition to the carrier switching that occurs after sending Msg1 as described in the previous embodiment, carrier switching may also occur after the network sends Msg2 (i.e., step S302) or after the UE sends Msg3 (i.e., step S303). Since only one carrier switching is generally possible during a random access process, assuming that the carrier switching occurs after sending Msg2 or Msg3, the first downlink carrier selected by the network in step S301 is a downlink carrier that belongs to the same beam / beam group as the first uplink carrier, that is, step S301 is completed according to the existing protocol.

[0105] Optionally, the network determines whether carrier switching occurs after sending Msg2 or sending Msg3 based at least on the UE's position, satellite ephemeris information, and the strength of the transmitted signal of Msg1. If the network determines that carrier switching occurs after sending Msg2 or sending Msg3, this message is indicated through Msg2 to inform the UE.

[0106] Optionally, if the Msg2 carries indication information of the second uplink carrier, the Msg2 indicates that carrier switching occurs after sending the Msg2, and determining the second uplink carrier includes: determining the second uplink carrier according to the indication information of the second uplink carrier.

[0107] The second uplink carrier indication information is used to indicate the uplink carrier (i.e., the second uplink carrier) on which Msg3 is transmitted. Optionally, the indication information may be the index of the second uplink carrier. Optionally, a new Media Access Control (layer) Control Element (MAC CE) or information element may be added to Msg2 to carry the second uplink carrier indication information.

[0108] Optionally, the second uplink carrier corresponds to a specific downlink carrier (i.e., the second downlink carrier), so that the network side can send Msg4 using the second downlink carrier corresponding to the second uplink carrier after receiving Msg3 sent through the second uplink carrier. The correspondence between the second uplink carrier and the specific downlink carrier can be configured for the UE by the network through RRC signaling or system broadcast messages.

[0109] Optionally, if the Msg2 carries indication information of the second downlink carrier, the Msg2 indicates that carrier switching is sent after sending Msg3, and after sending Msg3 through the second uplink carrier, it also includes: determining the second downlink carrier according to the indication information of the second downlink carrier.

[0110] The second downlink carrier indication information is used to indicate the downlink carrier (i.e., the second downlink carrier) on which Msg4 is transmitted. Optionally, the indication information may be the index of the second downlink carrier. Optionally, a new Media Access Control (layer) Control Element (MAC CE) or information element may be added to Msg2 to carry the second downlink carrier indication information.

[0111] In a specific embodiment, for the scenario of satellite Internet of Things, if it is considered that the UE may switch carriers after sending Msg2, the network configures the correspondence between the second downlink carrier and multiple uplink carriers through system broadcast information or RRC dedicated signaling, and each first downlink carrier is associated with multiple candidate Msg3 sending carriers. In addition, the network also needs to configure the downlink carrier corresponding to each candidate Msg3 sending carrier (such as through the index configuration of the downlink carrier) through system broadcast information or RRC dedicated signaling. These downlink carriers are the carriers used for Msg4 reception. The network indicates one of the multiple candidate Msg3 sending carriers as the second uplink carrier through Msg2, that is, Msg2 adds a new MAC CE or information element to carry the indication information of the second uplink carrier.

[0112] The UE determines the aforementioned inter-carrier association by receiving system broadcast information or RRC dedicated signaling. Upon receiving Msg2, the UE determines the second uplink carrier for sending Msg3, and then determines the receiving carrier for Msg4, i.e., the second downlink carrier, based on the downlink carrier associated with the determined carrier for sending Msg3.

[0113] See Figure 5 , Figure 5 This is a schematic diagram of the second carrier switching of an embodiment of the present invention. For example, assuming that the candidate Msg3 sending carrier associated with the downlink carrier D1 is: {U1, U2, U3}, wherein the downlink carrier D1 is associated with the uplink carrier associated with the uplink carrier U1, the downlink carrier D2 is associated with the uplink carrier U2, and the downlink carrier D3 is associated with the uplink carrier U3. beam1, beam2 and beam 3 (beam3) are three different beams / beam groups, U1 / D1 is the carrier corresponding to beam1, U2 and D2 are the carriers corresponding to beam2, and U3 and D3 are the carriers corresponding to beam3. Figure 5 , the satellite moves quickly to the left, and the UE selects carrier U1 (i.e., the first uplink carrier) in the coverage area of beam1 to send Msg1, and receives Msg2 on downlink carrier D1 (i.e., the first downlink carrier). For the network side, after receiving Msg1, the network will send Msg2 on carrier D1. The UE determines the uplink carrier for sending Msg3 based on the uplink carrier indicated by the indication information of the second uplink carrier in Msg2, that is, carrier U2 is the uplink carrier for sending Msg3. Then, the receiving carrier of Msg4 is determined based on the downlink carrier x associated with the determined Msg3 sending carrier, that is, D2 is used for receiving Msg4.

[0114] In a specific embodiment, for the scenario of satellite Internet of Things, if it is considered that the UE may switch carriers after sending Msg3, the network configures the association relationship between the second uplink carrier and multiple downlink carriers (i.e., multiple candidate Msg4 receiving carriers) through system broadcast information or RRC dedicated signaling. The network indicates one carrier among the multiple candidate Msg4 receiving carriers as the receiving carrier of Msg4 (i.e., the second downlink carrier) through Msg2, that is, Msg2 adds a new MACCE or information element to carry the indication information of the second downlink carrier. The UE determines the above-mentioned association relationship between carriers by receiving system broadcast information or RRC dedicated signaling. The UE determines the carrier for receiving Msg4 by receiving Msg2.

[0115] See Figure 6 , Figure 6This is a schematic diagram of the third carrier switching embodiment of the present invention. For example, assuming that the candidate Msg3 transmission carriers associated with the downlink carrier D1 are: {U1, U2, U3}, beam1, beam2 and beam3 are three different beams / beam groups, U1 / D1 is the carrier corresponding to beam1, D2 is the carrier corresponding to beam2, and D3 is the carrier corresponding to beam3. Figure 5 , the satellite moves quickly to the left, and the UE selects carrier U1 (i.e., the first uplink carrier) in the coverage area of beam1 to send Msg1, and receives Msg2 on downlink carrier D1 (i.e., the first downlink carrier). For the network side, after receiving Msg1, the network will send Msg2 on carrier D1. The UE determines the downlink carrier for sending Msg4 based on the uplink carrier indicated by the indication information of the second uplink carrier in Msg2, and continues to use carrier U1 as the uplink carrier for sending Msg3. Then, the receiving carrier of Msg4 is determined based on the downlink carrier associated with the determined Msg3 sending carrier (i.e., the second downlink carrier), that is, D2 is used for receiving Msg4.

[0116] In one embodiment, see again Figure 3 Before sending Msg3 to the network through the second uplink carrier in step S303, the method further includes: determining whether carrier switching occurs after sending Msg3; if carrier switching occurs, indicating the second target carrier to the network when sending Msg3, so that the network determines the second downlink carrier for sending Msg4 based on the second target carrier.

[0117] The second target carrier is a downlink carrier indicated by the UE to the network for sending Msg4. The second target carrier may be one or more downlink carriers.

[0118] After the UE receives Msg2 sent by the network side, the UE can also determine whether carrier switching occurs after sending Msg3. If carrier switching occurs, the UE instructs the network in Msg3 to use the downlink carrier included in other beams / beam groups to send Msg4, and the UE receives Msg4 on the corresponding downlink carrier.

[0119] Optionally, the UE predicts whether carrier switching will occur after sending Msg3 by measuring the candidate downlink carrier or based on satellite ephemeris information and current position information. For details, please refer to the relevant description of UE predicting whether carrier switching will occur after sending Msg1, which will not be repeated here.

[0120] Optionally, the second target carrier and the second downlink carrier are the same carrier, and the indication information of the second downlink carrier is carried in the Msg3, so that the network determines the second downlink carrier according to the indication information of the second downlink carrier.

[0121] The second downlink carrier indication information is used to indicate the downlink carrier (i.e., the second downlink carrier) on which Msg4 is transmitted. Optionally, the indication information may be the index of the second downlink carrier. Optionally, a new Media Access Control (layer) Control Element (MAC CE) or information element may be added to Msg3 to carry the second downlink carrier indication information.

[0122] Optionally, when the second target carrier is multiple carriers, the labels of the multiple carriers can be carried in Msg3; alternatively, multiple carriers belonging to different beams / beam groups can be treated as a carrier group, and associations between different preset identifiers and different carrier groups can be pre-established. The UE can only carry a certain preset identifier in Msg3 to indicate the corresponding carrier group. Furthermore, the association between different preset identifiers and different carrier groups can be configured by the network side to the UE through a system broadcast message or RRC signaling.

[0123] In the above embodiment, if carrier switching occurs after the network sends Msg2, or if carrier switching occurs after the UE sends Msg3, the network may indicate this to the UE via Msg2. Alternatively, the UE may indicate to the network via Msg3 that carrier switching occurred after sending Msg3.

[0124] Through the present invention Figures 3 to 6 In a corresponding embodiment, during the random access process, whenever a UE switches carriers, a corresponding carrier switching mechanism can be used to ensure that the UE and the network have consistent understanding of the carrier on which information is transmitted, thereby improving the success rate of random access. Furthermore, the solution of this embodiment of the present invention can ensure that the random access process of each UE is not restricted by carrier switching, thereby increasing system capacity.

[0125] The embodiment of the present invention also provides a random access method, see Figure 7 , the method comprising:

[0126] Step S701: receiving Msg1 sent by the UE via the first uplink carrier during random access;

[0127] Step S702: Select a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, and send the Msg2 to the UE through the first downlink carrier, so that the UE determines a second uplink carrier, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers;

[0128] Step S703: receiving Msg3 sent by the UE through the second uplink carrier;

[0129] Step S704: Determine a second downlink carrier for sending Msg4, and send the Msg4 to the UE through the second downlink carrier.

[0130] Optionally, the UE indicates a first target carrier when sending Msg1, and selecting the first downlink carrier to send Msg2 from multiple candidate downlink carriers includes: determining the first downlink carrier according to the first target carrier.

[0131] Optionally, different preamble codes and / or ROs are associated with each downlink carrier, the first target carrier and the first downlink carrier are the same carrier, and after the receiving UE sends the Msg1 through the first uplink carrier, it also includes: determining the first downlink carrier based on the preamble code and / or RO for sending the Msg1.

[0132] Optionally, the method further includes: configuring, for the UE through system broadcast information or RRC signaling, an association relationship between each downlink carrier and different preamble codes and / or ROs.

[0133] Optionally, the first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, and different preamble codes and / or ROs are associated with different carrier groups. The first downlink carrier for sending Msg2 is selected from multiple candidate downlink carriers, including: determining the carrier group corresponding to the first target carrier based on the sent Msg1 preamble code and / or RO, and using one or more carriers in the determined carrier group as the first downlink carrier.

[0134] Optionally, the method further includes: configuring association relationships between each carrier group and different preamble codes and / or ROs through system broadcast information or RRC signaling.

[0135] Optionally, the Msg2 is also used to indicate whether carrier switching occurs after sending Msg2 or after sending Msg3; wherein, when carrier switching occurs after sending Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; when carrier switching occurs after sending Msg2, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

[0136] Optionally, if the Msg2 carries indication information of the second uplink carrier, the Msg2 indicates that carrier switching is sent after sending the Msg2, and the UE determines the second uplink carrier according to the indication information of the second uplink carrier.

[0137] Optionally, if the Msg2 carries indication information of the second downlink carrier, the Msg2 indicates that carrier switching occurs after sending Msg3, and the UE determines the second downlink carrier according to the indication information of the second downlink carrier.

[0138] Optionally, if the Msg3 indicates a second target carrier, after receiving the Msg3 sent by the UE through the second uplink carrier, the method further includes: determining a second downlink carrier for sending Msg4 according to the second target carrier.

[0139] Optionally, the second target carrier and the second downlink carrier are the same carrier, the Msg3 carries indication information of the second downlink carrier, and the determining the second downlink carrier to send Msg4 based on the second target carrier includes: determining the second downlink carrier based on the indication information of the second downlink carrier.

[0140] about Figure 7 The random access method is executed by a network side device (such as a base station, access point (AP), etc.). For more information on its working principle and working method, please refer to Figures 3 to 6 The network side description will not be repeated here.

[0141] The embodiment of the present invention further provides a random access device 80, see Figure 8 , the random access device 80 includes:

[0142] An Msg1 sending module 801 is configured to send Msg1 to a network via a first uplink carrier during a random access process, so that the network selects a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, where the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers;

[0143] The Msg2 receiving module 802 is configured to receive the Msg2 sent by the network through the first downlink carrier;

[0144] The Msg3 sending module 803 is configured to determine a second uplink carrier and send the Msg3 to the network via the second uplink carrier, so that the network determines a second downlink carrier for sending the Msg4;

[0145] The Msg4 receiving module 804 is configured to receive Msg4 sent by the network through the second downlink carrier.

[0146] about Figure 8 For more information on the working principle and working method of the device, please refer to Figures 3 to 6 The relevant description will not be repeated here.

[0147] The embodiment of the present invention further provides a random access device 90, see Figure 9 , the random access device 90 includes:

[0148] The Msg1 receiving module 901 is configured to receive the Msg1 sent by the UE via the first uplink carrier during a random access process;

[0149] An Msg2 sending module 902 is configured to select a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, and send the Msg2 to the UE through the first downlink carrier, so that the UE determines a second uplink carrier, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers;

[0150] A Msg3 receiving module 903, configured to receive Msg3 sent by the UE through the second uplink carrier;

[0151] The Msg4 sending module 904 is configured to determine a second downlink carrier for sending Msg4, and send the Msg4 to the UE through the second downlink carrier.

[0152] about Figure 9 For more information on the working principle and working method of the device, please refer to Figure 7 The relevant description will not be repeated here.

[0153] An embodiment of the present invention further provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the steps of any of the methods described. The storage medium may be a computer-readable storage medium, such as a non-volatile memory or a non-transitory memory, and may also include an optical disk, a mechanical hard disk, a solid-state drive, and the like.

[0154] The embodiment of the present invention further provides a terminal, which may be a UE. The terminal may include a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the computer program when running the computer program. Figures 3 to 6 The steps of the method.

[0155] An embodiment of the present invention further provides a base station, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the computer program when running the computer program. Figure 7 The steps of the method.

[0156] Specifically, in the embodiment of the present invention, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0157] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0158] It should be understood that the term "and / or" as used herein simply describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " as used herein indicates that the related objects are in an "or" relationship.

[0159] The term "plurality" used in the embodiments of the present application refers to two or more.

[0160] The first, second, etc. descriptions appearing in the embodiments of this application are only for illustration and distinction of the description objects. There is no order, nor does it indicate any special limitation on the number of devices in the embodiments of this application, and cannot constitute any limitation on the embodiments of this application.

[0161] The "connection" appearing in the embodiments of the present application refers to various connection methods such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present application do not impose any limitations on this.

[0162] Although the present invention is disclosed above, it is not limited thereto. Any person skilled in the art may readily conceive of variations or substitutions, and may make various modifications and alterations without departing from the spirit and scope of the present invention. Combinations of the above-described functions and implementation steps, including software and hardware implementations, are all within the scope of protection of the present invention.

Claims

1. A random access method, characterized in that: The method comprises: During the random access process, sending Msg1 to the network through the first uplink carrier, so that the network selects a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving the Msg2 sent by the network through the first downlink carrier; Determine a second uplink carrier, and send Msg3 to the network through the second uplink carrier, so that the network determines a second downlink carrier to send Msg4; receiving Msg4 sent by the network through the second downlink carrier; When sending Msg1, a first target carrier is indicated to the network, so that the network determines the first downlink carrier according to the first target carrier, and the first target carrier is one or more carriers among the multiple candidate downlink carriers.

2. The method according to claim 1, characterized in that Before sending the Msg1 to the network through the first uplink carrier, the method further includes: Predict whether carrier switching occurs after sending Msg1, and if carrier switching occurs.

3. The method according to claim 2, characterized in that There is an association relationship between different preamble codes and / or ROs and each downlink carrier, the first target carrier is the first downlink carrier is the same carrier, and before indicating to the network that beam switching occurs when sending Msg1, it also includes: Obtaining a preamble code and / or RO associated with the first downlink carrier; The step of indicating the first target carrier to the network when sending Msg1, so that the network determines the first downlink carrier according to the target carrier, includes: The Msg1 is sent to the network through the acquired preamble code and / or RO, so that the network determines the first downlink carrier according to the acquired preamble code and / or RO.

4. The method according to claim 3, characterized in that The network configures the association between each downlink carrier and different preambles and / or ROs through system broadcast information or RRC signaling.

5. The method according to claim 3, characterized in that The first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, different preamble codes and / or ROs are associated with different carrier groups, and indicating to the network that beam switching occurs when sending Msg1 includes: Determining a preamble and / or RO associated with the first target carrier; The indicating to the network that the first target carrier occurs when sending Msg1 includes: The Msg1 is sent to the network through the determined preamble code and / or RO, so that the network determines the carrier group corresponding to the first target carrier according to the determined preamble code and / or RO, and uses one or more carriers in the determined carrier group as the first downlink carrier.

6. The method according to claim 5, characterized in that The network configures the association between each carrier group and different preambles and / or ROs through system broadcast information or RRC signaling.

7. The method according to claim 5 or 6, characterized in that If the number of the first downlink carrier exceeds one, the receiving the Msg2 through the first downlink carrier includes: Select a carrier from the first downlink carriers, and receive the Msg2 through the selected carrier.

8. The method according to claim 7, characterized in that The selecting a carrier from the first downlink carrier includes: A carrier with the best signal quality is selected from the first downlink carriers.

9. The method according to claim 2, characterized in that The determining whether carrier switching occurs after sending Msg1 includes: Whether carrier switching will occur after Msg1 is sent is predicted by measuring the candidate downlink carrier or according to satellite ephemeris information and current position information.

10. The method according to claim 1, characterized in that The Msg2 is further used to indicate whether carrier switching occurs after sending the Msg2 or after sending the Msg3. After receiving the Msg2 sent by the network through the first downlink carrier, the method further includes: Determining, according to the Msg2, whether carrier switching occurs after sending the Msg2 or after sending the Msg3; When carrier switching occurs after sending Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; When carrier switching occurs after Msg2 is sent, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

11. The method according to claim 10, characterized in that If the Msg2 carries indication information of the second uplink carrier, the Msg2 indicates that carrier switching occurs after sending the Msg2, and the determining the second uplink carrier includes: The second uplink carrier is determined according to the indication information of the second uplink carrier.

12. The method according to claim 10, characterized in that If the Msg2 carries indication information of the second downlink carrier, the Msg2 indicates that carrier switching is sent after sending the Msg3, and after sending the Msg3 through the second uplink carrier, the method further includes: The second downlink carrier is determined according to the indication information of the second downlink carrier.

13. The method according to claim 1, wherein Before sending Msg3 to the network through the second uplink carrier, the method further includes: Determine whether carrier switching occurs after sending Msg3. If carrier switching occurs, indicate the second target carrier to the network when sending Msg3, so that the network determines the second downlink carrier for sending Msg4 based on the second target carrier.

14. The method according to claim 13, characterized in that The second target carrier and the second downlink carrier are the same carrier, and the Msg3 carries indication information of the second downlink carrier, so that the network determines the second downlink carrier according to the indication information of the second downlink carrier.

15. A random access method, characterized in that: The method comprises: During the random access process, receiving Msg1 sent by the UE through the first uplink carrier; Selecting a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, and sending the Msg2 to the UE through the first downlink carrier, so that the UE determines a second uplink carrier, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; receiving Msg3 sent by the UE through the second uplink carrier; Determine a second downlink carrier for sending Msg4, and send the Msg4 to the UE through the second downlink carrier; The UE indicates a first target carrier when sending Msg1, where the first target carrier is one or more carriers among the multiple candidate downlink carriers. The selecting a first downlink carrier for sending Msg2 from a plurality of candidate downlink carriers includes: The first downlink carrier is determined according to the first target carrier.

16. The method according to claim 15, characterized in that There is an association relationship between different preamble codes and / or ROs and each downlink carrier, the first target carrier is the same carrier as the first downlink carrier, and after receiving the Msg1 sent by the UE through the first uplink carrier, the method further includes: The first downlink carrier is determined according to the preamble code and / or RO sent by the Msg1.

17. The method according to claim 16, characterized in that The method further includes: configuring, for the UE through system broadcast information or RRC signaling, association relationships between each downlink carrier and different preamble codes and / or ROs.

18. The method according to claim 15, characterized in that The first target carrier corresponds to a carrier group, each carrier group includes multiple carriers, different preamble codes and / or ROs are associated with different carrier groups, and selecting a first downlink carrier for sending Msg2 from multiple candidate downlink carriers includes: The carrier group corresponding to the first target carrier is determined according to the sent Msg1 preamble code and / or RO, and one or more carriers in the determined carrier group are used as the first downlink carrier.

19. The method according to claim 18, characterized in that The method further comprises: The association relationship between each carrier group and different preambles and / or ROs is configured through system broadcast information or RRC signaling.

20. The method according to claim 15, wherein The Msg2 is also used to indicate whether carrier switching occurs after sending Msg2 or after sending Msg3; When it is predicted that carrier switching occurs after sending Msg2, the first downlink carrier corresponds to multiple uplink carriers, and the second uplink carrier is one of the multiple uplink carriers corresponding to the first downlink carrier; When it is predicted that carrier switching occurs after sending Msg2, the second uplink carrier corresponds to multiple downlink carriers, and the second downlink carrier is one of the multiple downlink carriers corresponding to the second uplink carrier.

21. The method according to claim 20, characterized in that If the Msg2 carries the indication information of the second uplink carrier, the Msg2 indicates that carrier switching is sent after sending the Msg2, and the UE determines the second uplink carrier according to the indication information of the second uplink carrier.

22. The method according to claim 20, characterized in that If the Msg2 carries the indication information of the second downlink carrier, the Msg2 indicates that carrier switching occurs after sending the Msg3, and the UE determines the second downlink carrier according to the indication information of the second downlink carrier.

23. The method according to claim 15, wherein If the Msg3 indicates a second target carrier, after receiving the Msg3 sent by the UE through the second uplink carrier, the method further includes: A second downlink carrier for sending Msg4 is determined according to the second target carrier.

24. The method according to claim 23, wherein The second target carrier and the second downlink carrier are the same carrier, the Msg3 carries indication information of the second downlink carrier, and determining the second downlink carrier for sending the Msg4 according to the second target carrier includes: The second downlink carrier is determined according to the indication information of the second downlink carrier.

25. A random access device, characterized in that: The device comprises: An Msg1 sending module, configured to send Msg1 to a network through a first uplink carrier during a random access process, so that the network selects a first downlink carrier for sending Msg2 from a plurality of candidate downlink carriers, wherein the plurality of candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the plurality of candidate downlink carriers; A Msg2 receiving module, configured to receive the Msg2 sent by the network through the first downlink carrier; A Msg3 sending module, configured to determine a second uplink carrier and send Msg3 to the network via the second uplink carrier, so that the network determines a second downlink carrier for sending Msg4; A Msg4 receiving module, configured to receive Msg4 sent by the network through the second downlink carrier; The Msg1 sending module indicates a first target carrier to the network when sending Msg1, so that the network determines the first downlink carrier according to the first target carrier, and the first target carrier is one or more carriers among the multiple candidate downlink carriers.

26. A random access device, characterized in that: The device comprises: A Msg1 receiving module, configured to receive Msg1 sent by the UE via the first uplink carrier during a random access process; An Msg2 sending module, configured to select a first downlink carrier for sending Msg2 from multiple candidate downlink carriers, and send the Msg2 to the UE through the first downlink carrier, so that the UE determines a second uplink carrier, wherein the multiple candidate downlink carriers do not belong to the same beam / beam group, and the first uplink carrier corresponds to the multiple candidate downlink carriers; A Msg3 receiving module, configured to receive Msg3 sent by the UE through the second uplink carrier; A Msg4 sending module, configured to determine a second downlink carrier for sending Msg4, and send the Msg4 to the UE through the second downlink carrier; The UE indicates a first target carrier when sending Msg1, where the first target carrier is one or more carriers among the multiple candidate downlink carriers. The Msg2 sending module is further configured to determine the first downlink carrier according to the first target carrier.

27. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 14 or the steps of the method according to any one of claims 15 to 24 are executed.

28. A terminal comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor runs the computer program, the steps of the method according to any one of claims 1 to 14 are performed.

29. A base station comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor runs the computer program, the steps of the method according to any one of claims 15 to 24 are performed.

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