Four-step random access method, apparatus, terminal, network device and storage medium

Abstract

A four-step random access method, device, terminal, network equipment and storage medium. The method comprises: sending a first message Msg1; determining the preamble index in the first message Msg1 as the first identifier for receiving the second message Msg2, and determining the timing advance TA estimation value as the second identifier for receiving the second message Msg2; determining the media access control MAC random access response RAR to which the terminal itself belongs; replacing the TA estimation value, and completing the subsequent random access process using the MAC RAR to which the terminal itself belongs. The technical scheme of the embodiment of the application can improve the success probability of random access and reduce the average time delay of random access.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of mobile communication technology, specifically to a four-step random access method, apparatus, terminal, network device, and readable storage medium. Background Technology

[0002] like Figure 1 As shown, in the existing technology of 4-step Random Access Channel (4-step RACH), the terminal and the base station need to exchange information four times to complete random access.

[0003] Specifically, in 4-step RACH, the first step of random access is for the terminal to randomly select a preamble sequence from the orthogonal preamble sequence configured by the base station and transmit it during a random access event (RACH Occasion, RO). However, in the current 4-step RACH, the maximum size of the preamble sequence candidate set for a single cell is 64. Therefore, if two or more User Equipment (UE) devices select the same preamble sequence for random access on the same RO, a collision will occur. Future 6G networks may reach a connection density of 10 million devices per square kilometer. Even if the activation probability of each terminal is as low as 0.01%, there will still be 1000 devices in the same cell initiating random access requests at the same time. If the current preamble set size is maintained, the probability of preamble collisions will further increase.

[0004] In particular, when the distance between the UEs colliding with the preamble and the base station varies, the proximity effect causes the base station to identify multiple identical preambles on the same RO, resulting in multiple different Time Advance (TA) values. Since the base station cannot confirm the correspondence between multiple TA values ​​and multiple UEs colliding with the preamble, it must add a Backoff Indicator (BI) subheader to the Random Access Response (RAR) of message Msg2. The backoff value in this subheading indicates the time range the UE needs to wait before retransmitting the preamble. UEs receiving the BI need to wait for a certain period before initiating random access. The waiting time for each UE is a random value selected from the waiting time interval specified by the BI.

[0005] The near-far effect further increases the probability of preamble collisions and also increases the average access delay of 4-step RACH. Even if the base station can identify the number of UEs sending the same preamble, because the preamble indexes of the above UEs are completely identical, the base station cannot provide each UE with its own TA value in message Msg2 on a one-to-one basis. At this time, the base station can only send BI and notify the UE to re-initiate random access in the random backoff state. Summary of the Invention

[0006] At least one embodiment of the present invention provides a four-step random access method, apparatus, terminal, network device, and readable storage medium to solve the problems of increased collision probability and long average access latency in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0008] In a first aspect, embodiments of the present invention provide a four-step random access method, the method comprising:

[0009] Send the first message Msg1;

[0010] The leading index in the first message Msg1 is determined as the first identifier for receiving the second message Msg2, and the estimated timing advance (TA) value is determined as the second identifier for receiving the second message Msg2.

[0011] Determine the Media Access Control (MAC) Random Access Response (RAR) to which you belong;

[0012] Replace the estimated TA value with the TA value in the MAC RAR to which it belongs, and use the MAC RAR to which it belongs to complete the subsequent random access process.

[0013] Optionally, the method further includes estimating the TA value based on the following method before sending the first message Msg1:

[0014] The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or

[0015] Use historical TA values ​​as the estimated TA value before this random access; or

[0016] The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or

[0017] The estimated value of the TA is obtained using the downlink sensing reference signal.

[0018] Optionally, the determination of the Media Access Control (MAC) Random Access Response (RAR) to which it belongs includes:

[0019] The estimated TA value is compared with the individual TA values ​​in multiple MAC RARs sent from the base station;

[0020] Based on the comparison results, the MAC RAR issued by the base station that is closest to the estimated TA value is determined as the MAC RAR to which the base station belongs.

[0021] Optionally, the method further includes:

[0022] Receive multiple MAC RARs sent from the base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO).

[0023] Optionally, the determination of the Media Access Control (MAC) Random Access Response (RAR) to which it belongs further includes:

[0024] After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU).

[0025] After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or

[0026] If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

[0027] Optionally, replacing the estimated TA value with the TA value in the MAC RAR to which the device belongs, and using the TA value in the MAC RAR to which the device belongs to complete the subsequent random access process includes:

[0028] Using the TA value in its own MAC RAR, the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4 are completed.

[0029] Secondly, embodiments of the present invention provide a four-step random access method for the network side, the method comprising:

[0030] Receive the first message Msg1;

[0031] The leading index in the first message Msg1 is determined as the first identifier for sending the second message Msg2, and the estimated timing advance TA is determined as the second identifier for sending the second message Msg2.

[0032] Configure multiple Media Access Control (MAC) Random Access Responses (RARs) for the preamble, and send the MAC RARs via the second message Msg2.

[0033] Optionally, configuring multiple Media Access Control (MAC) Random Access Responses (RARs) for the preamble and sending the MAC RARs via the second message Msg2 includes:

[0034] If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then the MAC RAR is configured and the MAC RAR is sent through the second message Msg2.

[0035] Optionally, the step of configuring the MAC RAR and sending the MAC RAR via the second message Msg2 if it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1 includes:

[0036] If multiple related peaks higher than the detection threshold are detected within the detection range of a certain preamble, and the time difference between adjacent related peaks is greater than the maximum multipath delay of the cell, it is determined that multiple terminals selected multiple identical preambles in the same RO when sending the first message Msg1.

[0037] Optionally, the method further includes:

[0038] When feeding back the second message Msg2, at least one RAR is configured for a certain preamble on a certain RO, including:

[0039] When it is determined that multiple terminals selected the same preamble on the same RO when sending the first message Msg1, a subheader and at least one MACRAR are set in the MAC subPDU for that preamble in the second message Msg2.

[0040] The number of MAC RARs is consistent with the number of terminals that send the preamble on the RO.

[0041] Optionally, setting a subheader in the MAC subPDU for the preamble of the second message Msg2 includes:

[0042] Add a RAR count indicator field to the subheader, the field being used to indicate the number of MAC RARs corresponding to the preamble.

[0043] Optionally, setting at least one MAC RAR in the MAC subPDU for the preamble of the second message Msg2 includes:

[0044] In at least one MAC RAR for the preamble, the contents of each MAC RAR are different, wherein the TA value of each MAC RAR corresponds to the TA value of a terminal that sent the preamble on the RO.

[0045] Thirdly, embodiments of the present invention provide a four-step random access device, the device comprising:

[0046] The message sending unit is used to send the first message Msg1;

[0047] The receiving message identification determination unit is used to determine the leading index in the first message Msg1 as the first identifier for receiving the second message Msg2, and to determine the timing advance TA estimate as the second identifier for receiving the second message Msg2.

[0048] The MAC RAR determination unit is used to determine the Media Access Control (MAC) Random Access Response (RAR) to which it belongs.

[0049] The TA estimate replacement unit is used to replace the TA estimate with the TA value in the MAC RAR to which it belongs, and to use the MAC RAR to which it belongs to complete the subsequent random access process.

[0050] Optionally, the device further includes a TA value estimation unit, used to estimate the TA value based on the following method before sending the first message Msg1:

[0051] The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or

[0052] Use historical TA values ​​as the estimated TA value before this random access; or

[0053] The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or

[0054] The estimated value of the TA is obtained using the downlink sensing reference signal.

[0055] Optionally, the MAC RAR determination unit includes:

[0056] The TA value comparison unit is used to compare the estimated TA value with each TA value in multiple MAC RARs sent from the base station;

[0057] The MAC RAR determination unit, based on the comparison results, determines the MAC RAR issued by the base station that is closest to the TA estimate as its own MAC RAR.

[0058] Optionally, the apparatus further includes a MAC RAR receiving unit for receiving multiple MAC RARs sent from the base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO).

[0059] Optionally, the MAC RAR determination unit is further configured to:

[0060] After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU).

[0061] After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or

[0062] If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

[0063] Optionally, the TA estimate replacement unit is further configured to: use the TA value and other fields in the MAC RAR to which it belongs to complete the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4.

[0064] Fourthly, embodiments of the present invention provide a four-step random access device for the network side, the device comprising:

[0065] The message receiving unit is used to receive the first message Msg1;

[0066] The message sending identifier determination unit determines the leading index in the first message Msg1 as the first identifier for sending the second message Msg2, and determines the estimated timing advance TA as the second identifier for sending the second message Msg2.

[0067] The MAC RAR distribution unit configures multiple Media Access Control (MAC) Random Access Response (RAR) for the preamble and distributes the MAC RAR.

[0068] Optionally, the MAC RAR distribution unit is further configured to:

[0069] If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then the MAC RAR is configured and the MAC RAR is sent.

[0070] Fifthly, embodiments of the present invention provide a terminal, including the four-step random access device described above.

[0071] In a sixth aspect, embodiments of the present invention provide a network device, which includes the four-step random access device for the network side as described above.

[0072] In a seventh aspect, embodiments of the present invention provide a network device, including: a processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the method described in the second aspect.

[0073] Eighthly, embodiments of the present invention provide a network device, including: a processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the method described in the first aspect.

[0074] In a ninth aspect, embodiments of the present invention provide a readable storage medium storing a program that, when executed by a processor, implements the steps of the method as described in the first or second aspect.

[0075] The four-step random access method, apparatus, terminal, network device, and readable storage medium provided in this invention have the following beneficial technical effects compared with the prior art: they can partially avoid the random access failure problem caused by preamble collision and reduce the average random access latency. Attached Figure Description

[0076] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0077] Figure 1 This is a schematic diagram of the existing 4-step random access process.

[0078] Figure 2 A flowchart of the four-step random access method provided in this embodiment of the invention;

[0079] Figure 3 Another flowchart of the four-step random access method provided in this embodiment of the invention;

[0080] Figure 4 A flowchart for determining the Media Access Control (MAC) Random Access Response (RAR) to which it belongs, provided in an embodiment of the present invention;

[0081] Figure 5 A flowchart for receiving multiple MAC RARs sent from a base station, provided as an embodiment of the present invention;

[0082] Figure 6 A flowchart for replacing the TA estimate and completing the subsequent random access process, provided for embodiments of the present invention;

[0083] Figure 7 A flowchart of a four-step random access method for the network side provided in an embodiment of the present invention;

[0084] Figure 8 A flowchart for configuring and issuing MAC RAR for a preamble provided in an embodiment of the present invention;

[0085] Figure 9 This is a schematic diagram of the structure of the four-step random access device provided in an embodiment of the present invention;

[0086] Figure 10 This is another structural schematic diagram of the four-step random access device provided in an embodiment of the present invention;

[0087] Figure 11 This is a schematic diagram of the structure of the MAC RAR determination unit provided in an embodiment of the present invention;

[0088] Figure 12 A schematic diagram of the structure of a four-step random access device for the network side provided in an embodiment of the present invention;

[0089] Figure 13This is a schematic diagram illustrating the configuration of the Media Access Control Protocol Data Unit (MACPDU) in the second message Msg2 provided in an embodiment of the present invention.

[0090] Figure 14 A schematic diagram of a network device provided in an embodiment of the present invention;

[0091] Figure 15 This is a schematic diagram of a terminal provided in an embodiment of the present invention. Detailed Implementation

[0092] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0093] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The terms "and / or" in the specification and claims indicate at least one of the connected objects.

[0094] The technologies described in this document are not limited to NR systems and Long Time Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in various wireless communication systems such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. CDMA systems can implement radio technologies such as CDMA2000 and Universal Terrestrial Radio Access (UTRA). UTRA includes Wideband Code Division Multiple Access (WCDMA) and other CDMA variants. TDMA systems can implement radio technologies such as the Global System for Mobile Communication (GSM). OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolution-UTRA (E-UTRA), IEEE 802.21 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and more advanced versions of LTE (such as LTE-A) are newer UMTS versions using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). CDMA2000 and UMB are described in documents from an organization called 3rd Generation Partnership Project 2 (3GPP2).The techniques described herein can be used with the systems and radio technologies mentioned above, as well as with other systems and radio technologies. However, the following description describes NR systems for illustrative purposes, and NR terminology is used in most of the following description, although these techniques can also be applied to applications beyond NR systems.

[0095] The following description provides examples and is not intended to limit the scope, applicability, or configuration set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the spirit and scope of this disclosure. Various procedures or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to certain examples may be combined in other examples.

[0096] Please refer to Figure 1 The present invention provides a four-step random access method, the method comprising:

[0097] Step 21: Send the first message Msg1;

[0098] Step 22: Determine the leading index in the first message Msg1 as the first identifier for receiving the second message Msg2, and determine the estimated timing advance (TA) as the second identifier for receiving the second message Msg2.

[0099] Step 23: Determine the Media Access Control (MAC) Random Access Response (RAR) to which you belong;

[0100] Step 24: Replace the estimated TA value with the TA value in the MAC RAR to which the user belongs, and use the MAC RAR to which the user belongs to complete the subsequent random access process.

[0101] Figure 3 Another flowchart of the four-step random access method provided in this embodiment of the invention. Specifically, as shown... Figure 3 As shown, the method further includes:

[0102] Step 31: Before sending the first message Msg1, estimate the TA value based on the following method:

[0103] The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or

[0104] Use historical TA values ​​as the estimated TA value before this random access; or

[0105] The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or

[0106] The estimated value of the TA is obtained using the downlink sensing reference signal.

[0107] Figure 4 This is a flowchart illustrating how the Media Access Control (MAC) Random Access Response (RAR) determines its own identity, as provided in an embodiment of the present invention. Specifically, as shown... Figure 4 As shown, step 23 includes:

[0108] Step 41: Compare the estimated TA value with each TA value in the multiple MAC RARs sent from the base station;

[0109] Step 42: Based on the comparison results, determine the MAC RAR issued by the base station that is closest to the estimated TA as the MAC RAR to which it belongs.

[0110] Figure 5 This is a flowchart illustrating the process of receiving multiple MAC RARs sent from a base station, as provided in an embodiment of the present invention. Specifically, as shown... Figure 5 As shown, the method further includes:

[0111] Step 51: Receive multiple MAC RARs sent from the base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO).

[0112] Specifically, step 23 also includes:

[0113] After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU).

[0114] After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or

[0115] If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

[0116] Figure 6 This is a flowchart illustrating how the estimated TA value is replaced and the subsequent random access process is completed, as provided in an embodiment of the present invention. Specifically, as... Figure 6 As shown, step 24 includes:

[0117] Step 61: Using the TA value and other fields in the MAC RAR to which it belongs, complete the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4.

[0118] Figure 7 This is a flowchart of a four-step random access method for the network side provided in an embodiment of the present invention. The method includes:

[0119] Step 71: Receive the first message Msg1;

[0120] Step 72: Determine the leading index in the first message Msg1 as the first identifier for sending the second message Msg2, and determine the estimated timing advance TA as the second identifier for sending the second message Msg2.

[0121] Step 73: Configure multiple Media Access Control (MAC) Random Access Responses (RARs) for the preamble, and send the MAC RARs through the second message Msg2.

[0122] Figure 8 This is a flowchart illustrating the configuration of MAC RAR for a preamble and the sending of MAC RAR via the second message Msg2, provided as an embodiment of the present invention. Specifically, as shown... Figure 8 As shown, step 73 includes:

[0123] Step 81: If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then configure the MAC RAR and send the MAC RAR through the second message Msg2.

[0124] Specifically, step 81 includes:

[0125] If multiple related peaks higher than the detection threshold are detected within the detection range of a certain preamble, and the time difference between adjacent related peaks is greater than the maximum multipath delay of the cell, it is determined that multiple terminals selected multiple identical preambles in the same RO when sending the first message Msg1.

[0126] The method further includes:

[0127] When feeding back the second message Msg2, at least one RAR is configured for a certain preamble on a certain RO, including:

[0128] When it is determined that multiple terminals selected the same preamble on the same RO when sending the first message Msg1, a subheader and at least one MACRAR are set in the MAC subPDU for that preamble in the second message Msg2.

[0129] The number of MAC RARs is consistent with the number of terminals that send the preamble on the RO.

[0130] Specifically, setting a subheader in the MAC subPDU for the preamble of the second message Msg2 includes:

[0131] Add a RAR count indicator field to the subheader, the field being used to indicate the number of MAC RARs corresponding to the preamble.

[0132] Specifically, setting at least one MAC RAR in the MAC subPDU for the preamble of the second message Msg2 includes:

[0133] In at least one MAC RAR for the preamble, the contents of each MAC RAR are different, wherein the TA value of each MAC RAR corresponds to the TA value of a terminal that sent the preamble on the RO.

[0134] like Figure 9 As shown, this embodiment of the invention provides a schematic diagram of a four-step random access device 90. The device 90 includes:

[0135] Message sending unit 91 is used to send the first message Msg1;

[0136] The message identification determination unit 92 is used to determine the leading index in the first message Msg1 as the first identifier for receiving the second message Msg2, and to determine the timing advance TA estimate as the second identifier for receiving the second message Msg2.

[0137] MAC RAR determination unit 93 is used to determine the Media Access Control (MAC) Random Access Response (RAR) to which it belongs;

[0138] The TA estimate replacement unit 94 is used to replace the TA estimate with the TA value in the MAC RAR to which it belongs, and to use the MAC RAR to which it belongs to complete the subsequent random access process.

[0139] Figure 10 This is another structural schematic diagram of the four-step random access device provided in an embodiment of the present invention. Specifically, as shown... Figure 10As shown, the device 90 further includes a TA value estimation unit 101, used to estimate the TA value based on the following method before sending the first message Msg1:

[0140] The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or

[0141] Use historical TA values ​​as the estimated TA value before this random access; or

[0142] The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or

[0143] The estimated value of the TA is obtained using the downlink sensing reference signal.

[0144] Figure 11 This is a schematic diagram of the structure of the MAC RAR determination unit provided in an embodiment of the present invention. Specifically, as shown... Figure 11 As shown, the MAC RAR determination unit 93 includes:

[0145] The TA value comparison unit 111 is used to compare the estimated TA value with each TA value in multiple MAC RARs sent from the base station;

[0146] The MAC RAR determination unit 112 determines the MAC RAR issued by the base station that is closest to the TA estimate as its own MAC RAR based on the comparison result.

[0147] The apparatus further includes a MAC RAR receiving unit for receiving multiple MAC RARs sent from a base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO).

[0148] Specifically, the MAC RAR determination unit 93 is further configured to:

[0149] After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU).

[0150] After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or

[0151] If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

[0152] The TA estimate replacement unit 94 is also used to: use the TA value and other fields in the MAC RAR to which it belongs to complete the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4.

[0153] like Figure 12 As shown, this embodiment of the invention provides a structural schematic diagram of a four-step random access device 120 for use on the network side. The device 120 includes:

[0154] Message receiving unit 121 is used to receive the first message Msg1;

[0155] The message sending identifier determination unit 122 determines the leading index in the first message Msg1 as the first identifier for sending the second message Msg2, and determines the estimated timing advance TA as the second identifier for sending the second message Msg2.

[0156] The MAC RAR sending unit 123 configures multiple Media Access Control (MAC) Random Access Response (RAR) for the preamble and sends the MAC RAR.

[0157] The MAC RAR sending unit 123 is also used for:

[0158] If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then the MAC RAR is configured and the MAC RAR is sent.

[0159] The MAC RAR sending unit 123 is also used for:

[0160] If multiple related peaks higher than the detection threshold are detected within the detection range of a certain preamble, and the time difference between adjacent related peaks is greater than the maximum multipath delay of the cell, it is determined that multiple terminals selected multiple identical preambles in the same RO when sending the first message Msg1.

[0161] Specifically, when feeding back the second message Msg2, at least one RAR is configured for a certain preamble on a certain RO, including:

[0162] When it is determined that multiple terminals selected the same preamble on the same RO when sending the first message Msg1, a subheader and at least one MACRAR are set in the MAC subPDU for that preamble in the second message Msg2.

[0163] The number of MAC RARs is consistent with the number of terminals that send the preamble on the RO.

[0164] The provision of setting a subheader in the MAC subPDU for the preamble of the second message Msg2 includes:

[0165] Add a RAR count indicator field to the subheader, the field being used to indicate the number of MAC RARs corresponding to the preamble.

[0166] Specifically, setting at least one MAC RAR in the MAC subPDU for the preamble of the second message Msg2 includes:

[0167] In at least one MAC RAR for the preamble, the contents of each MAC RAR are different, wherein the TA value of each MAC RAR corresponds to the TA value of a terminal that sent the preamble on the RO.

[0168] The following example illustrates the transmission of Msg1 by five terminals on the same RO. It is assumed that terminal 1 transmits preamble index = 2, terminals 2 and 3 transmit preamble index = 4, and terminals 4 and 5 transmit preamble index = 6. Furthermore, the distances between terminals 2 and 3, and terminals 4 and 5, which transmit the same preamble, and the base stations are significantly different.

[0169] Therefore, when the base station detects the RO, it will detect one correlation peak with a preamble index of 2, two correlation peaks with a preamble index of 4, and two correlation peaks with a preamble index of 6.

[0170] In this embodiment, assuming that all five terminals can pre-estimate the TA based on the downlink synchronization signal or historical TA value, the MAC PDU format corresponding to the Msg2 returned by the base station after receiving Msg1 from these five terminals is as follows: Figure 13 shown. Specifically, Figure 13 This is a schematic diagram of the configuration of the Media Access Control Protocol Data Unit (MAC PDU) in the second message Msg2 provided in an embodiment of the present invention.

[0171] like Figure 13As shown, after each terminal successfully addresses the PDCCH using RA-RNTI, it finds its own MAC subPDU by comparing the preamble selected in Msg1 with the RAPID in each MAC subPDU. Figure 3 For example, terminal 1 detects that RAPID = 2 in MAC subPDU 1, which is consistent with the preamble index it sent. Terminal 1 then checks the RAR number indicator (RN) field in the subheader and finds that this field is bit 0. Therefore, there is only one RAR after this subheader, and terminal 1 uses the content of MAC RAR 1 to complete the subsequent Msg3 and Msg4 processes.

[0172] For terminals 2 and 3, they first detect that RAPID = 4 and RN = 1 in MAC subPDU 2, indicating that there are multiple RARs in this MAC subPDU. Terminal 2 compares the estimated TA value before sending Msg1 with TA2 in MAC RAR 2 and TA3 in MAC RAR 3, respectively. It finds that TA2 is close to its estimated TA value, so terminal 2 uses the content in MAC RAR 2 to complete the subsequent 4-step RACH access process. Terminal 3 operates similarly to terminal 2, and will ultimately use MAC RAR 3 to complete the subsequent process.

[0173] The operation of terminals 4 and 5 is similar to that of terminals 2 and 3. They confirm from MAC subPDU 3 that MAC RAR 4 and MAC RAR 5 are their own Msg2 received content, and complete the subsequent 4-step RACH access process accordingly.

[0174] Please refer to Figure 14 The present invention also provides a network device 140, including a processor 141, a memory 142, and a computer program stored in the memory 142 and executable on the processor 141. When the computer program is executed by the processor 141, it implements the various processes of the random access method embodiments executed by the network device described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0175] Please refer to Figure 15 The present invention also provides a terminal 150, including a processor 151, a memory 152, and a computer program stored in the memory 152 and executable on the processor 151. When the computer program is executed by the processor 151, it implements the various processes of the random access method embodiment executed by the terminal described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0176] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements each process of the above-described four-step random access method embodiment and achieves the same technical effect. To avoid repetition, it will not be described again here. The computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0177] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve the following beneficial technical effects:

[0178] In this application, by configuring multiple MACRARs for the aforementioned preamble collision and near-far effect terminals and completing one-to-one Msg2 feedback, the success probability of random access can be improved and the average latency of random access can be reduced.

[0179] The terminal uses both the first identifier and the second identifier to complete the lookup and confirmation of the MAC RAR, which will not cause confusion for the terminal. In this application, the preamble index is used as the first identifier for the terminal to send Msg1, and the estimated TA value is used as the second identifier for the terminal to send Msg1. When the terminal confirms that the RAPID of the subheader in a certain MAC subPDU matches the first identifier and the RN field is 1, it further compares the second identifier with the TA values ​​in multiple subsequent RARs to find the unique MAC RAR and continue the subsequent random access process, without causing confusion for the terminal in receiving the MAC RAR.

[0180] Once the terminal confirms the MAC RAR, it discards the estimated TA value and uses the TA value and other fields from the MAC RAR. Although the terminal can use the downlink synchronization signal as a reference signal to estimate the TA, the time resolution of the estimated TA value may be relatively low compared to the TA accuracy obtained through uplink preamble. Therefore, once the terminal confirms its own MAC RAR, it replaces the potentially inaccurate estimated TA value and uses the more accurate TA value from the MAC RAR to complete the subsequent random access procedure.

[0181] Furthermore, since this application avoids the occurrence of BI, in the embodiments of this application, the field (e.g., the T field) of the subheader in the MAC subPDU can be changed to the RAR number indication field RN. When RN=0, it means that there is only one MAC RAR after the subheader. The terminal receiving the MAC subPDU can use the MAC RAR after confirming the first identifier, without having to confirm whether the TA value is close to the estimated TA value. When RN=1, it means that there are multiple MAC RARs after the subheader. In addition to confirming the first identifier, the terminal also needs to compare the second identifier, i.e. the estimated TA value, with the TA value in each RAR to find the closest TA value and confirm the corresponding MAC RAR.

[0182] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0183] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0184] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A four-step random access method, characterized in that, The method includes: Send the first message Msg1; The leading index in the first message Msg1 is determined as the first identifier for receiving the second message Msg2, and the estimated timing advance (TA) value is determined as the second identifier for receiving the second message Msg2. Determine the Media Access Control (MAC) Random Access Response (RAR) to which you belong; Replace the estimated TA value with the TA value in the MAC RAR to which it belongs, and use the MAC RAR to which it belongs to complete the subsequent random access process. The method further includes: Receive multiple MAC RARs sent from the base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO); The method for determining the Media Access Control (MAC) Random Access Response (RAR) to which it belongs also includes: After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU). After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

2. The method as described in claim 1, characterized in that, The method further includes estimating the TA value based on the following method before sending the first message Msg1: The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or The historical TA value is used as the estimated TA value before this random access; or The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or The estimated value of the TA is obtained using the downlink sensing reference signal.

3. The method as described in claim 1, characterized in that, The determination of its own Media Access Control (MAC) Random Access Response (RAR) includes: The estimated TA value is compared with each TA value in multiple MAC RARs sent from the base station; Based on the comparison results, the MAC RAR issued by the base station that is closest to the estimated TA value is determined as the MAC RAR to which the base station belongs.

4. The method as described in claim 1, characterized in that, The step of replacing the estimated TA value with the TA value in the MAC RAR to which the device belongs, and using the TA value in the MAC RAR to which the device belongs to complete the subsequent random access process, includes: Using the TA value and other fields in its own MAC RAR, the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4 are completed.

5. A four-step random access method for the network side, characterized in that, The method includes: Receive the first message Msg1; The leading index in the first message Msg1 is determined as the first identifier for sending the second message Msg2, and the estimated timing advance TA is determined as the second identifier for sending the second message Msg2. Configure multiple Media Access Control (MAC) Random Access Responses (RARs) for the preamble, and send the MAC RARs through the second message Msg2; The method further includes: When feeding back the second message Msg2, at least one RAR is configured for a certain preamble on a certain RO, including: When it is determined that multiple terminals selected the same preamble on the same RO when sending the first message Msg1, a subheader and at least one MAC RAR are set in the MAC subPDU for that preamble in the second message Msg2. The number of MAC RARs is the same as the number of terminals that send the preamble on the RO. Setting a subheader in the MAC subPDU for the preamble of the second message Msg2 includes: Add a RAR count indicator field to the subheader, the field being used to indicate the number of MACRARs corresponding to the preamble; Setting at least one MAC RAR in the MAC subPDU for the preamble of the second message Msg2 includes: In at least one MAC RAR for the preamble, the contents of each MAC RAR are different, wherein the TA value of each MAC RAR corresponds to the TA value of a terminal that sent the preamble on the RO.

6. The method as described in claim 5, characterized in that, The configuration of multiple Media Access Control (MAC) Random Access Responses (RARs) for the preamble, and the sending of the MAC RARs via the second message Msg2, includes: If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then the MAC RAR is configured and the MAC RAR is sent through the second message Msg2.

7. The method as described in claim 6, characterized in that, The description of configuring the MAC RAR and sending the MAC RAR via the second message Msg2 if it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1 includes: If multiple related peaks higher than the detection threshold are detected within the detection range of a certain preamble, and the time difference between adjacent related peaks is greater than the maximum multipath delay of the cell, it is determined that multiple terminals selected multiple identical preambles in the same RO when sending the first message Msg1.

8. A four-step random access device, characterized in that, The device includes: The message sending unit is used to send the first message Msg1; The receiving message identification determination unit is used to determine the leading index in the first message Msg1 as the first identifier for receiving the second message Msg2, and to determine the timing advance TA estimate as the second identifier for receiving the second message Msg2. The MAC RAR determination unit is used to determine the Media Access Control (MAC) Random Access Response (RAR) to which it belongs. The TA estimate replacement unit is used to replace the TA estimate with the TA value in the MAC RAR to which it belongs, and to use the MAC RAR to which it belongs to complete the subsequent random access process. The apparatus further includes a MAC RAR receiving unit, which is used to receive multiple MAC RARs sent from the base station, wherein the multiple MAC RARs are configured by the base station for multiple identical preambles for the same random access opportunity (RO). The MAC RAR determination unit is also used for: After successfully listening to the Physical Downlink Control Channel (PDCCH) using the Random Access Radio Network Temporary Identifier (RA-RNTI), the subheader corresponding to the preamble is searched in the Media Access Control Protocol Data Unit (MAC PDU). After finding the RAPID field that matches the preceding header, if the MAC RAR count indicator field in the subheader is 0 bits, then the MAC RAR following the subheader is the MAC RAR to which it belongs, or If the RAR count indicator field in the subheader is 1 bit, then the estimated TA value before sending the first message Msg1 is compared with the TA value in each MAC RAR after the subheader to find the TA value in the MAC RAR sent by the base station that is closest to the estimated TA value. The MAC RAR where the TA value is located is the MAC RAR to which the message belongs.

9. The apparatus as claimed in claim 8, characterized in that, The device further includes a TA value estimation unit, used to estimate the TA value based on the following method before sending the first message Msg1: The TA value is estimated using the downlink synchronization signal to obtain the estimated TA value; or Use historical TA values ​​as the estimated TA value before this random access; or The downlink positioning reference signal is used to estimate the TA value to obtain the estimated TA value; or The estimated value of the TA is obtained using the downlink sensing reference signal.

10. The apparatus as claimed in claim 8, characterized in that, The MAC RAR determination unit includes: The TA value comparison unit is used to compare the estimated TA value with each TA value in multiple MAC RARs sent from the base station; The MAC RAR determination unit, based on the comparison results, determines the MAC RAR issued by the base station that is closest to the TA estimate as its own MAC RAR.

11. The apparatus as claimed in claim 8, characterized in that, The TA estimate replacement unit is also used to: use the TA value and other fields in the MAC RAR to which it belongs to complete the subsequent sending of the third message Msg3 and the receiving of the fourth message Msg4.

12. A four-step random access device for the network side, characterized in that, The device includes: The message receiving unit is used to receive the first message Msg1; The message sending identifier determination unit determines the leading index in the first message Msg1 as the first identifier for sending the second message Msg2, and determines the estimated timing advance TA as the second identifier for sending the second message Msg2. The MAC RAR distribution unit configures multiple Media Access Control (MAC) Random Access Response (RAR) for the preamble and distributes the MAC RAR. The device is also used for: When it is determined that multiple terminals selected the same preamble on the same RO when sending the first message Msg1, a subheader and at least one MAC RAR are set in the MAC subPDU for that preamble in the second message Msg2. The number of MAC RARs is the same as the number of terminals that send the preamble on the RO. Setting a subheader in the MAC subPDU for the preamble of the second message Msg2 includes: Add a RAR count indicator field to the subheader, the field being used to indicate the number of MACRARs corresponding to the preamble; Setting at least one MAC RAR in the MAC subPDU for the preamble of the second message Msg2 includes: In at least one MAC RAR for the preamble, the contents of each MAC RAR are different, wherein the TA value of each MAC RAR corresponds to the TA value of a terminal that sent the preamble on the RO.

13. The apparatus as claimed in claim 12, characterized in that, The MAC RAR sending unit is also used for: If it is determined that multiple terminals selected multiple identical preambles at the same random access time (RO) when sending the first message Msg1, then the MAC RAR is configured and the MAC RAR is sent.

14. A terminal, characterized in that, include: A processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the method as described in any one of claims 1 to 4.

15. A network device, characterized in that, include: A processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the method as described in any one of claims 5 to 7.

16. A readable storage medium, characterized in that, The readable storage medium stores a program that, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 7.

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