Random access method and device

Abstract

A random access method and a device, relating to the technical field of communications, capable of reducing random access conflicts and contentions, and improving the number of terminals actually accessing a network. Specifically, the method can comprise: a terminal may send to a network device a random access preamble carrying first scrambling code information. Then, the terminal may receive a random access response (RAR) from the network device, the RAR carrying second scrambling code information.

Description

Random access method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 8, 2024, with application number 202410178249.5 and invention name “Random Access Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communication technologies, and in particular to a random access method and device. Background Art

[0003] As the number of terminals continues to increase, the number of terminals actually accessing the network also needs to continue to increase. For the terminal, the terminal can establish a connection with the base station and obtain uplink synchronization through a random access procedure. In the random access procedure, the terminal can select time-frequency resources and a preamble, and send the preamble to the network device. Afterwards, the network device can send a random access response (Random Access Response, RAR) to the terminal based on the received preamble. The terminal can identify whether the RAR is the RAR that is replying to the terminal based on the random access-radio network temporary identity (RA-RNTI) and preamble ID carried in the received RAR. After determining that the RAR is the RAR that is replying to the terminal, the terminal can use the uplink resources corresponding to the preamble to perform the first uplink scheduling transmission with the network device.

[0004] However, the RA-RNTI is associated with the time-frequency resource used by the terminal to transmit the preamble. Each terminal requires a different time-frequency resource or preamble ID to obtain the corresponding uplink resource and access the network. This means that the number of terminals that can access the network is limited by the time-frequency resource and preamble ID used to transmit the preamble. Therefore, increasing the number of terminals that can actually access the network has become a pressing technical issue. Summary of the Invention

[0005] The present application provides a random access method and device, which can reduce random access conflicts and competitions and increase the number of terminals actually accessing the network.

[0006] In a first aspect, the present application provides a random access method that can be applied to a terminal. In this method, the terminal can send a random access preamble carrying first scrambling code information to a network device. Thereafter, the terminal can receive a random access response (RAR) from the network device based on the first scrambling code information. The RAR carries second scrambling code information.

[0007] Based on the above technical solution, not only does the random access preamble sent by the terminal to the network device carry scrambling code information, but the terminal can also receive the RAR that also carries the scrambling code information. In this way, when the time-frequency resources used to send the random access preamble and the random access preamble are the same, the terminal can find the RAR sent back to it based on the scrambling code information and use the corresponding uplink resources to send MSG3, thereby increasing the number of terminals accessing the network.

[0008] In combination with the first aspect, in one possible design, the RAR includes: a physical downlink control channel (PDCCH) scrambled using a first random access identification code (radio access network temporary identifier, RA-RNTI), and the first RA-RNTI is determined based on the second scrambling code information.

[0009] That is, the PDCCH is scrambled based on the second scrambling code information. In this way, the PDCCH in the RAR can carry the second scrambling code information.

[0010] In combination with the first aspect, in another possible design, the first RA-RNTI is determined based on the second scrambling code information and time-frequency information.

[0011] In combination with the first aspect, in another possible design manner, the bits occupied by the second scrambling code information in the first RA-RNTI are higher than the bits occupied by the time-frequency information in the first RA-RNTI.

[0012] It is understandable that by adding the second scrambling code information to the high bits of the first RA-RNTI, modification of the low bits of the RA-RNTI can be avoided. This ensures that terminals that cannot recognize the newly added information in the RA-RNTI can continue to recognize the low bits.

[0013] In combination with the first aspect, in another possible design, the method may further include: the terminal uses a second RA-RNTI to monitor the PDCCH, where the second RA-RNTI is determined based on the first scrambling code information. Afterwards, if the PDCCH is successfully descrambled using the second RA-RNTI, the terminal can obtain the first random access preamble identifier in the RAR. If the first random access preamble identifier is the same as the second random access preamble identifier, the terminal determines that the RAR is the RAR of the reply terminal, the second random access preamble identifier is the identifier of the random access preamble sent by the terminal, and the second RA-RNTI is determined based on the first scrambling code information.

[0014] It is understood that the terminal monitors the PDCCH using the second RA-RNTI determined based on the first scrambling code information. In this way, the terminal can determine, based on the second RA-RNTI, whether the RAR is a response to the first scrambling code information. If the PDCCH is successfully descrambled using the second RA-RNTI, it indicates that the RAR is a response to the first scrambling code information. The first random access preamble identifier and the second random access preamble identifier can then be used to determine whether the RAR is a response to the terminal. This ensures that terminals using different scrambling code information receive different RARs, reducing random access conflicts and contention, and increasing the number of terminals actually accessing the network.

[0015] In combination with the first aspect, in another possible design, the method may further include: if the PDCCH is successfully de-scrambled using the second RA-RNTI, and the first random access preamble identifier is different from the second random access preamble identifier, the terminal continues to use the second RA-RNTI to monitor the PDCCH.

[0016] It is understood that the terminal monitors the PDCCH using the second RA-RNTI determined based on the first scrambling code information. In this way, the terminal can determine, based on the second RA-RNTI, whether the RAR is a response to the first scrambling code information. If descrambling the PDCCH using the second RA-RNTI fails, it indicates that the RAR is not a response to the first scrambling code information. The terminal can continue to monitor the PDCCH using the second RA-RNTI to find a response to the first scrambling code information.

[0017] In combination with the first aspect, in another possible design, the method may further include: if the de-scrambling of the PDCCH using the second RA-RNTI fails, the terminal continues to monitor the PDCCH using the second RA-RNTI.

[0018] It is understandable that the terminal can monitor the PDCCH using the second RA-RNTI determined based on the first scrambling code information. In this way, the terminal can determine whether the RAR is a response to the first scrambling code information based on the second RA-RNTI. If the PDCCH is successfully descrambled using the second RA-RNTI, but the first random access preamble identifier and the second random access preamble identifier are different, it means that the RAR is a response to the first scrambling code information, but the subcarriers are different. In this case, the terminal can continue to monitor the PDCCH using the second RA-RNTI to find a response to the first scrambling code information.

[0019] In combination with the first aspect, in another possible design, the RAR includes: a medium access control control element (MAC CE), and the MAC CE includes: second scrambling code information.

[0020] In combination with the first aspect, in another possible design, the MAC CE also includes: a first random access preamble identifier, where the first random access preamble identifier is used to indicate frequency domain information for sending the random access preamble.

[0021] That is, the MAC CE includes code domain information and frequency domain information for sending the RAR.

[0022] In combination with the first aspect, in another possible design, the method may further include: the terminal using a second RA-RNTI to monitor the PDCCH. If the PDCCH is successfully descrambled using the second RA-RNTI, the terminal receives a MAC CE based on the PDCCH and obtains a first random access preamble identifier and second scrambling code information from the MAC CE. Thereafter, if the first random access preamble identifier is the same as the second random access preamble identifier, and the first scrambling code information is the same as the second scrambling code information, the terminal determines that the RAR is the RAR of the reply terminal, and the second random access preamble identifier is the identifier of the random access preamble sent by the terminal.

[0023] Based on the above solution, after monitoring the PDCCH using the second RA-RNTI, the terminal can determine whether the RAR is intended for the terminal based on whether the first random access preamble identifier and the second random access preamble identifier are identical, and whether the first scrambling code information and the second scrambling code information are identical. In this way, the terminal can determine whether the RAR is intended for the terminal based on both code domain information and frequency domain information. This ensures that terminals using different scrambling code information receive different RARs, reducing random access conflicts and contention, and increasing the number of terminals actually accessing the network.

[0024] In combination with the first aspect, in another possible design, if the first RA-RNTI is the same as the second RA-RNTI, the PDCCH is successfully descrambled using the second RA-RNTI.

[0025] In combination with the first aspect, in another possible design, the RAR further includes: uplink resources. The method further includes: the terminal using the uplink resources in the RAR to send a third message Msg3 to the network device.

[0026] In combination with the first aspect, in another possible design manner, the method further includes: the terminal obtains scrambling code configuration information, where the scrambling code configuration information includes: at least one scrambling code and the number of scrambling codes.

[0027] It is understandable that the network device broadcasts the scrambling code configuration information so that the terminal can obtain the scrambling code configuration information and send a random access preamble carrying the scrambling code information, thereby increasing the number of random access preambles recognized by the network device.

[0028] In combination with the first aspect, in another possible design, the scrambling code is an orthogonal cover code (OCC).

[0029] In a second aspect, the present application provides a random access method that can be applied to a network device. In this method, the network device can receive a random access preamble from a terminal, the random access preamble carrying first scrambling code information. Thereafter, the network device sends a random access response (RAR) to the terminal, the RAR carrying second scrambling code information.

[0030] Based on the above technical solution, after receiving a random access preamble carrying the first scrambling code information, the network device can also transmit the RAR message back to the terminal containing the scrambling code information, allowing the terminal to receive the RAR message containing the scrambling code information. In this way, when the time-frequency resources used to transmit the random access preamble and the random access preamble are the same, the terminal can find the RAR message sent to it based on the scrambling code information and use the corresponding uplink resources to send Msg3, thereby increasing the number of terminals accessing the network.

[0031] In combination with the second aspect, in a possible design, the RAR includes: a PDCCH scrambled using a first random access identification code RA-RNTI, where the first RA-RNTI is determined based on the second scrambling code information.

[0032] In combination with the second aspect, in another possible design, the first RA-RNTI is determined based on the second scrambling code information and time-frequency information.

[0033] In combination with the second aspect, in another possible design manner, the bits occupied by the second scrambling code information in the first RA-RNTI are higher than the bits occupied by the time-frequency information in the first RA-RNTI.

[0034] In combination with the second aspect, in another possible design, the RAR includes: MAC CE, and the MAC CE includes: second scrambling code information.

[0035] In combination with the second aspect, in another possible design, the MAC CE also includes: a first random access preamble identifier, where the first random access preamble identifier is used to indicate frequency domain information for sending the random access preamble.

[0036] In conjunction with the second aspect, in another possible design, the RAR further includes: uplink resources. The method further includes: the network device receiving Msg3 from the terminal.

[0037] In combination with the second aspect, in another possible design, the method further includes: the network device broadcasts scrambling code configuration information, where the scrambling code configuration information includes: at least one scrambling code and the number of scrambling codes.

[0038] In combination with the second aspect, in another possible design, the scrambling code is OCC.

[0039] In a third aspect, the present application provides a terminal, comprising: a processor coupled to a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory, so that the terminal performs the method described in the first aspect and any possible design thereof.

[0040] In a fourth aspect, the present application provides a network device, comprising: a processor coupled to a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory, so that the network device performs the method described in the second aspect and any possible design thereof.

[0041] In a fifth aspect, the present application provides a chip system. The chip system includes one or more interface circuits and one or more processors. The interface circuits and processors are interconnected via wiring. The interface circuits are configured to receive signals from a computer memory and send the signals to the processors. The signals include computer instructions stored in the memory. When the processors execute the computer instructions, the computer executes the method described in the first aspect, the second aspect, and any possible design thereof.

[0042] In a sixth aspect, the present application provides a computer-readable storage medium, which includes computer instructions. When the computer instructions are executed on a computer, the computer executes the method described in the first aspect, the second aspect and any possible design thereof.

[0043] In a seventh aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the method described in the first aspect, the second aspect, and any possible design thereof.

[0044] It can be understood that the beneficial effects that can be achieved by the terminal described in the third aspect and any possible design thereof, the network device described in the fourth aspect and any possible design thereof, the chip system described in the fifth aspect, the computer-readable storage medium described in the sixth aspect, and the computer program product described in the seventh aspect can refer to the beneficial effects in the first aspect, the second aspect and any possible design thereof, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a flowchart of a random access method provided by an embodiment of the present application;

[0046] FIG2 is a schematic diagram of an example of a terminal-initiated random access process provided in an embodiment of the present application;

[0047] FIG3 is a schematic diagram of an example of a random access preamble identifier provided in an embodiment of the present application;

[0048] FIG4 is a schematic diagram of another example of a terminal-initiated random access process provided in an embodiment of the present application;

[0049] FIG5 is a schematic diagram of the structure of a communication system provided in an embodiment of the present application;

[0050] FIG6 is a schematic diagram of the structure of another communication system provided in an embodiment of the present application;

[0051] FIG7 is a flow chart of a random access method provided in an embodiment of the present application;

[0052] FIG8 is a schematic diagram of an example of a reserved domain provided in an embodiment of the present application;

[0053] FIG9 is a schematic diagram of another example of a reserved domain provided in an embodiment of the present application;

[0054] FIG10 is a flow chart of another random access method provided in an embodiment of the present application;

[0055] FIG11 is a flow chart of another random access method provided in an embodiment of the present application;

[0056] FIG12 is a flow chart of a random access method provided in an embodiment of the present application;

[0057] FIG13 is a flow chart of a random access method provided in an embodiment of the present application;

[0058] FIG14 is a schematic diagram of the structural composition of a chip system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0059] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0060] In this application, the character " / " generally indicates that the preceding and following objects are in an "or" relationship. For example, A / B can be understood as A or B.

[0061] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this embodiment, unless otherwise specified, "plurality" means two or more.

[0062] Furthermore, the terms "including," "having," and any variations thereof, as used in the description of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules is not limited to the listed steps or modules, but may optionally include other steps or modules not listed, or may optionally include other steps or modules inherent to the process, method, product, or apparatus.

[0063] Additionally, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present concepts in a concrete manner.

[0064] With the continuous advancement of communications technology, fourth-generation (4G) and fifth-generation (5G) cellular communication technologies can be integrated into satellite communication systems to improve the coverage of satellite communication networks. For example, the new radio (NR) non-terrestrial network (NTN) for terminals (such as mobile phones and computers) adapts 5G NR technology to satellite systems, using satellite systems to provide wider 5G signal coverage in remote areas. Another example is the Internet of Things (IoT) NTN, which adapts 4G narrowband (NB)-IoT for low-cost IoT terminals to satellites, enabling satellites to provide low-cost IoT connectivity coverage. After improving network coverage, terminals need to use a random access procedure with network equipment (such as a base station) to access the serving cell and use the satellite communication network. The following describes the random access procedure for terminals in NB-IoT.

[0065] As shown in FIG1 , the random access process may include:

[0066] S101: Send a random access preamble to a network device.

[0067] In an embodiment of the present application, when a terminal initiates a random access procedure, the terminal may select a random access time-frequency resource and a random access preamble based on the system broadcast configuration. The terminal may then send a random access request, i.e., the selected random access preamble, on the selected time-frequency resource. The random access request may be used to indicate to the network device that the terminal requires random access.

[0068] The following describes the process of a terminal selecting a video resource and selecting a random access preamble.

[0069] A serving cell may have multiple uplink carriers (UL carriers). Each UL carrier has a bandwidth of 180 kHz and is equipped with random access resources (such as random access time domain resources, random access preamble resources, and the corresponding downlink carrier (DL carrier) for receiving the RAR). Each random access resource may correspond to a different coverage level, and random access preambles sent on different UL carriers may correspond to the same DL carrier for receiving the RAR. The terminal can select a UL carrier from multiple UL carriers based on the corresponding coverage level.

[0070] After selecting a UL carrier, the terminal can initiate random access at a permitted timing based on the coverage level and transmission timing configuration (period, starting position, etc.). The terminal can also select a random access preamble from the selected UL carrier. Selecting a random access preamble by the terminal is equivalent to selecting the subcarrier on which the random access preamble is transmitted. In other words, the identifier of a random access preamble corresponds to the identifier of a subcarrier.

[0071] S102: Send a random access response to the terminal.

[0072] In an embodiment of the present application, a network device may reply with a random access response (RAR) to a received random access preamble. A RAR may include replies to different random access preambles sent on the same time-frequency resource. Accordingly, the terminal may receive the RAR.

[0073] It should be noted that the process of receiving the RAR by the terminal can be divided into receiving the PDCCH part of the RAR and the physical downlink shared channel (PDSCH) part of the RAR.

[0074] The PDCCH part is used to transmit scheduling information, which is used to instruct the terminal to receive and process data in the PDSCH part. For example, the PDCCH part may include: the format of the PDSCH transmission, the time-frequency information of the PDSCH transmission, the modulation and coding scheme, etc.

[0075] The PDSCH part is used to transmit terminal information related to random access. For example, the PDSCH part includes: the MAC CE of RAR, which includes: the uplink resources for sending Msg3, the terminal's temporary cell radio network temporary identifier (TC-RNTI), the terminal's timing advance (TA), and the random access preamble ID (rapid). The TC-RNTI is used for subsequent data transmission and scheduling, and the random access preamble ID can be used to indicate the subcarrier for sending the random access preamble.

[0076] S103: Send a third message to the network device.

[0077] In this embodiment of the present application, S103 is the Scheduled Transmission portion of the random access process. The terminal can determine the random access identifier (RA-RNTI) based on the time-frequency resources used to transmit the random access preamble, and descramble the PDCCH using the RA-RNTI to obtain RAR scheduling information. RA-RNTI = 1 + floor(SFN_id / 4) + 256 * carrier_id. SFN_id indicates the time domain starting position, and carrier_id indicates uplink carrier information.

[0078] The terminal can then receive the PDSCH based on the RAR scheduling information. If the RAR contains a response to the random access preamble selected by the terminal, the terminal can use the TA in the MAC CE to adjust the timing of sending uplink data to achieve uplink synchronization. In addition, the terminal can use uplink resources to send Msg3, which includes the terminal's identifier (such as TC-RNTI and short-term mobile subscriber identity (S-TMSI)).

[0079] For example, as shown in Figure 2, User Equipment (UE) 1 selects uplink carrier 1 and random access preamble 2 (i.e., subcarrier 2), and transmits random access preamble 2 at time 1. UE2 selects uplink carrier 2 and random access preamble 1 (i.e., subcarrier 1), and transmits random access preamble 1 at time 1. If uplink carrier 1 and uplink carrier 2 are both associated with the same DL carrier 1, the network device can reply to the UE that sent the random access preamble on both uplink carrier 1 and uplink carrier 2 via DL carrier 1. Because UE1 and UE2 transmit random access preambles at the same time, their floor (SFN_id / 4) is the same. Because UE1 and UE2 select different uplink carriers, their carrier_ids are different. Therefore, UE1 and UE2 have different RA-RNTIs. UE1 and UE2 can use the RA-RNTI to descramble the PDCCH and obtain different RAR scheduling information.

[0080] Alternatively, suppose UE3 (not shown) selects uplink carrier 1 and random access preamble 4 (i.e., subcarrier 4) and transmits at time 1. Since UE1 and UE3 share the same time domain starting position and uplink carrier information, their RA-RNTIs are also the same, and different RA-RNTIs cannot be used to obtain different RAR scheduling information. UE1 and UE3 can then determine a response to the random access preamble selected by UE1 and UE3 based on the random access preamble identifier.

[0081] As shown in FIG3 , the octet (oct) 301 is an oct in MACE, and the oct 301 includes a rapid.

[0082] S104: Send a fourth message to the terminal.

[0083] In this embodiment of the present application, S104 represents the contention resolution portion of the random access procedure. After receiving Msg3 containing the terminal's TC-RNTI, if the terminal is allowed access, the network device responds with the terminal's TC-RNTI in a fourth message, Msg4, indicating successful contention resolution and allowing the terminal access. The terminal's TC-RNTI is updated to the C-RNTI. The terminal can then use the C-RNTI for data transmission.

[0084] However, in the above random access process, the number of terminals that can access the network is limited by the time-frequency resources and random access preamble identifiers for sending random access preambles. In order to increase the number of terminals that can access the network, an OCC can be superimposed when sending random access preambles.

[0085] For example, as shown in Figure 4, UE1 selects uplink carrier 1 and random access preamble 2 (i.e., subcarrier 2), superimposes OCC1, and transmits at opportunity 1. UE2 selects uplink carrier 1 and random access preamble 2 (i.e., subcarrier 2), superimposes OCC2, and transmits at opportunity 1. The base station can then distinguish UE1 and UE2 based on the OCC and respond with a RAR for each. However, the PDCCH portion (RA-RNTI) and the PDSCH portion (random access preamble ID) in the RAR do not reflect the OCC information.

[0086] As a result, if multiple terminals select the same random access preamble to send at the same time on the same uplink carrier, each terminal cannot distinguish the OCC corresponding to the RAR, nor can it determine whether the RAR is a reply to its own. In this way, although the random access preambles sent by multiple terminals can be expanded through the OCC, multiple terminals may simultaneously use the uplink resources corresponding to the same random access preamble to send MSG3, exacerbating random access conflicts and contention, resulting in no change in the number of terminals actually accessing the network. Therefore, how to increase the number of terminals actually accessing the network has become a pressing technical issue.

[0087] To this end, embodiments of the present application provide a random access method. In this method, a terminal can send a random access preamble carrying scrambling code information to a network device. The network device can then feed back a Random Access Response (RAR) carrying the scrambling code information to the terminal, allowing the terminal to receive the RAR carrying the scrambling code information. In this way, when the time-frequency resources used to send the random access preamble and the random access preamble are the same, the terminal can find the RAR sent to the terminal based on the scrambling code information and use the corresponding uplink resources to send MSG3, thereby increasing the number of terminals accessing the network.

[0088] It should be noted that the embodiments of the present application do not limit the random access process. For example, the random access process can be contention-based random access (i.e., the four-step random access shown in Figure 1), non-contention-based random access, two-step random access, etc. The following takes four-step random access as an example to introduce the embodiments of the present application. In addition, the random access process mentioned in the embodiments of the present application can be applied to scenarios such as initial access, re-access after radio link failure, uplink data arrival and the need to apply for uplink resources, etc., and the embodiments of the present application do not limit this.

[0089] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application will be described in detail using the communication system shown in Figure 5 as an example. For example, Figure 5 is a schematic diagram of the architecture of a communication system applicable to the random access method provided in the embodiments of the present application. As shown in Figure 5, the communication system includes a terminal and a network device.

[0090] Wherein, the above-mentioned terminal is a terminal that accesses the above-mentioned communication system and has a wireless transceiver function or a chip or chip system that can be set at the terminal. The terminal can also be called a user device, an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent or a user device. The terminal in the embodiment of the present application can be a mobile phone, a tablet computer, a computer with a wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a vehicle-mounted terminal, an RSU with terminal function, a physical network terminal, etc. The terminal of the present application can also be a vehicle-mounted module, vehicle-mounted module, vehicle-mounted component, vehicle-mounted chip or vehicle-mounted unit built into the vehicle as one or more components or units. The vehicle can implement the communication method provided by the present application through the built-in vehicle-mounted module, vehicle-mounted module, vehicle-mounted component, vehicle-mounted chip or vehicle-mounted unit.

[0091] The above-mentioned network device is a device located on the network side of the above-mentioned communication system and having wireless transceiver functions, or a chip or chip system that can be set in the device. The network device includes but is not limited to: a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved NodeB, or home NodeB, HNB), a baseband unit (BBU), a wireless relay node, a wireless backhaul node, a transmission point (TRP or transmission point, TP), etc., and can also be 5G, such as a gNB in ​​a new radio (NR) system, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), a distributed unit (DU), a road side unit (RSU) with base station functions, etc.

[0092] Optionally, the network device can also be an access network device carried on the flight platform. When the access network device is carried on the flight platform, it moves synchronously with the flight platform, and the access network device and the flight platform can be considered as a whole. In this case, the flight platform can be regarded as the access network device, or it can be described as operating in regenerative mode, that is, the flight platform has the functions of an access network device. In addition, the communication link between the flight platform and the terminal device can be called a service link.

[0093] It should be noted that the flight platform can be a satellite, drone, or other aircraft. For example, the flight platform can include a geostationary orbit satellite, a non-geostationary orbit satellite, a low-orbit satellite, a medium-orbit satellite, a geosynchronous orbit satellite, an unmanned aerial system platform, or a high-orbit satellite, without limitation.

[0094] Alternatively, the network device may be an access network device distributedly mounted on the flight platform based on a distributed unit (DU). When the access network device is distributedly mounted on the flight platform based on the DU, the flight platform can be considered as part of the access network device, or it can be described as operating in a regenerative mode, that is, the flight platform has the functions of a partial access network device.

[0095] In some other embodiments, the communication system may further include: a flying platform. As shown in FIG6 , the communication system may include: a network device, a terminal, and a flying platform.

[0096] Among them, the network device is an access network device set up on the ground, and the terminal device and the access network device can communicate through the flight platform to forward signals. Specifically, the flight platform and the access network device can communicate through the next generation (NG) interface. The flight platform can provide a wireless access transmission / reception point (TRP) for the terminal device. The TRP can transparently transmit data between the terminal device and the access network device, thereby realizing the communication connection between the terminal device and the access network device. At this time, it can be described as the flight platform working in transparent mode. It should be noted that the access network device can also be described as a gateway station, ground station, etc., without limitation.

[0097] It should be noted that the methods in the following embodiments can all be implemented in the above-mentioned communication system. The solutions in the embodiments of the present application can also be applied to other communication systems, and the corresponding names can also be replaced by the names of corresponding functions in other communication systems.

[0098] After introducing the application scenario and implementation environment of the embodiment of the present application, the random access method provided by the embodiment of the present application is described in detail below in combination with the above implementation environment.

[0099] An embodiment of the present application provides a random access method, as shown in FIG7 , which may include:

[0100] S701: Send a random access preamble carrying first scrambling code information to a network device.

[0101] The first scrambling code information is information of the first scrambling code.

[0102] Exemplarily, the scrambling code information may be a scrambling code identifier (such as a scrambling code ID or a scrambling code index).

[0103] In a possible implementation, the terminal may use an uplink carrier to send a random access preamble carrying the first scrambling code information.

[0104] In one possible design, before sending the random access preamble, the terminal may use a first scrambling code to scramble the random access preamble so that the random access preamble carries the first scrambling code information.

[0105] Optionally, the terminal may use the first scrambling code information and the random access configuration information to scramble the random access preamble, so that the random access preamble carries the first scrambling code information.

[0106] The random access configuration information includes at least one of the following: frequency domain information, time domain information, and a random access preamble identifier. The frequency domain information may be used to indicate an uplink carrier for transmitting a random access preamble, the time domain information may be used to indicate a time for transmitting a random access preamble, and the random access preamble identifier may be used to indicate a random access preamble to be transmitted.

[0107] Exemplarily, the random access preamble identifier may be rapid, or the random access preamble identifier may be a preamble index.

[0108] In some embodiments, before the terminal sends a random access preamble carrying the first scrambling code information to the network device, the terminal may obtain the first scrambling code information.

[0109] In a possible implementation, the terminal may pre-configure multiple scrambling code information and a scrambling code corresponding to each scrambling code information. Afterwards, the terminal may obtain the first scrambling code information from the multiple scrambling code information.

[0110] Exemplarily, the terminal may pre-configure multiple scrambling code indexes and a scrambling code corresponding to each scrambling code index.

[0111] In another possible implementation, the network device may broadcast scrambling code configuration information. The terminal may then obtain the scrambling code configuration information. The scrambling code configuration information includes: at least one scrambling code and a number of scrambling codes. The number of scrambling codes is the number of scrambling codes included in the scrambling code configuration information.

[0112] In one possible design, the scrambling code may be an OCC.

[0113] Optionally, the scrambling code configuration information may further include: a first corresponding relationship, where the first corresponding relationship is a corresponding relationship between each scrambling code and scrambling code information, where one scrambling code corresponds to one scrambling code information.

[0114] For example, as shown in Table 1, it shows the correspondence between scrambling codes and scrambling code information.

[0115] Table 1

[0116] That is, when the scrambling code information is 0, the corresponding scrambling code is scrambling code sequence 1. When the scrambling code information is 1, the corresponding scrambling code is scrambling code sequence 2. When the scrambling code information is n, the corresponding scrambling code is scrambling code sequence m.

[0117] It should be noted that the embodiment of the present application does not limit the number of scrambling codes. For example, the number of scrambling codes can be 8, 32, 64, etc.

[0118] In an embodiment of the present application, a network device may broadcast a system information block (SIB) carrying scrambling code configuration information via a broadcast channel. A terminal may then receive the SIB and determine a first scrambling code from at least one scrambling code. The terminal may then determine first scrambling code information corresponding to the first scrambling code based on the first scrambling code.

[0119] In one possible design, the SIB may be SIB2, SIB22, SIB23, etc.

[0120] Optionally, the SIB may also include: random access configuration information.

[0121] It is understandable that the network device broadcasts the scrambling code configuration information so that the terminal can obtain the scrambling code configuration information and send a random access preamble carrying the scrambling code information, thereby increasing the number of random access preambles recognized by the network device.

[0122] S702: Receive a random access preamble from the terminal.

[0123] In some embodiments, after the network device receives a random access preamble from the terminal, the network device may determine a second scrambling code based on the scrambled random access preamble. Thereafter, the network device may determine second scrambling code information based on the second scrambling code and the first correspondence, where the second scrambling code information is information about the second scrambling code.

[0124] It should be noted that the network device may receive random access preambles carrying scrambling code information from multiple terminals. The second scrambling code information is the scrambling code information carried in any random access preamble received by the network device. In other words, the second scrambling code information may be the same as the first scrambling code information, or may be different from the first scrambling code information. This is not limited in this embodiment of the present application.

[0125] S703: Send a random access response to the terminal.

[0126] The RAR carries the second scrambling code information.

[0127] In a possible implementation, the network device may generate a RAR carrying the second scrambling code information according to the second scrambling code information. Thereafter, the network device may send the RAR carrying the second scrambling code information to the terminal via a DL carrier.

[0128] The RAR may include at least one of the following: a random access preamble identifier, an uplink timing adjustment command, an uplink resource for sending the MSG3 message, a TC-RNTI, and a backoff parameter. The random access preamble identifier is the identifier of the random access preamble received by the network device. The uplink timing adjustment command is used to adjust the terminal's transmission time. The backoff parameter indicates the length of time the terminal needs to wait after receiving the RAR.

[0129] It should be noted that in the embodiment of the present application, the network device can generate a RAR carrying the second scrambling code information in two ways (method 1 and method 2). Among them, method 1 is to scramble the PDCCH part in the RAR using the second scrambling code information, and method 2 is to indicate the second scrambling code information through the MAC CE in the RAR.

[0130] The following first introduces a process in which the network device scrambles the PDCCH part in the RAR using the second scrambling code information in the first approach so that the RAR carries the second scrambling code information.

[0131] In one possible design, the network device may generate a first RA-RNTI based on the second scrambling code information. Thereafter, the network device may scramble the PDCCH in the RAR based on the first RA-RNTI to generate a RAR carrying the second scrambling code information.

[0132] The RAR includes: a PDCCH scrambled by using a first RA-RNTI, where the first RA-RNTI is determined based on second scrambling code information.

[0133] In one possible implementation, the network device may generate a first RA-RNTI based on the second scrambling code information and the random access configuration information. Thereafter, the network device may scramble the PDCCH in the RAR based on the first RA-RNTI to generate a RAR carrying the second scrambling code information.

[0134] The first RA-RNTI is determined based on the second scrambling code information and time-frequency information. The time-frequency information can be used to indicate the time domain resources and frequency domain resources used to send the random access preamble carrying the second scrambling code information.

[0135] Optionally, the time-frequency information may be used to indicate time domain resources and / or frequency domain resources used for sending a random access preamble carrying the second scrambling code information.

[0136] That is, the time-frequency information may include: time domain information and / or frequency domain information. The first RA-RNTI may be determined based on the second scrambling code information and the time domain information, or the first RA-RNTI may be determined based on the second scrambling code information and the frequency domain information.

[0137] In the embodiment of the present application, the bits occupied by the time-frequency information in the first RA-RNTI are different from the bits occupied by the second scrambling code information in the first RA-RNTI.

[0138] In one possible design, the bits occupied by the second scrambling code information in the first RA-RNTI are higher than the bits occupied by the time-frequency information in the first RA-RNTI.

[0139] In an exemplary embodiment, RA-RNTI can be expressed by Formula 1.

[0140] RA-RNTI=1+floor(SFN_id / 4)+256*carrier_id+x*OCC_index Formula 1.

[0141] Among them, SFN_id is used to indicate the identifier of the starting frame number for sending the random access preamble (that is, information on time domain resources), carrier_id is used to indicate the identifier of the uplink carrier for sending the random access preamble (that is, information on frequency domain resources), OCC_index is used to indicate the index position of the scrambling code information, and x is an integer greater than or equal to 4096.

[0142] It should be noted that the maximum value of SFN_id is 1023, and the maximum number of uplink carriers available for random access is 16. Therefore, 1 + floor (1023 / 4) + 256 * 15 = 1 + 255 + 256 * 15 = 4096. To ensure that the scrambling code information is located in the high bit position of the RA-RNTI, x needs to be greater than or equal to 4096, that is, the minimum value of x is 4096.

[0143] It should be understood that the above is an example of RA-RNTI, and x can actually be determined based on time-frequency information, that is, the bits occupied by the second scrambling code information in the first RA-RNTI are determined by the time-frequency information, and this embodiment of the present application is not limited to this.

[0144] It is understandable that by adding the second scrambling code information to the high bits of the first RA-RNTI, modification of the low bits of the RA-RNTI can be avoided. This enables backward compatibility for terminals, ensuring that terminals that cannot recognize the newly added information in the RA-RNTI can continue to recognize the low bits.

[0145] In another possible design, the bits occupied by the second scrambling code information in the first RA-RNTI are lower than the bits occupied by the time-frequency information in the first RA-RNTI.

[0146] Illustratively, the bits occupied by the second scrambling code information are between the bits occupied by the time domain information and the bits occupied by the frequency domain information. Alternatively, the bits occupied by the second scrambling code information are lower than the bits occupied by the time domain information and the bits occupied by the frequency domain information.

[0147] That is, the structure of the RA-RNTI can be changed, that is, when the scrambling code information is added, the bits occupied by the time-frequency information can be changed at the same time.

[0148] The above is an introduction to the process of scrambling the PDCCH part in the RAR using the second scrambling code information in method 1 so that the RAR carries the second scrambling code information. The following is an introduction to the process of indicating the second scrambling code information through the MAC CE in method 2 so that the RAR carries the second scrambling code information.

[0149] In a possible implementation, the network device may indicate the second scrambling code information according to a reserved field of the RAR, so that the RAR indicates the second scrambling code information through a MAC CE, wherein the RAR includes a MAC CE, and the MAC CE includes the second scrambling code information.

[0150] In one possible design, the network device may indicate the second scrambling code information through the first reserve field. Alternatively, the network device may indicate the second scrambling code information through the second reserve field. Alternatively, the network device may indicate the second scrambling code information through the first reserve field and the reserve field.

[0151] Optionally, the number of bits in the first reserve field is different from the number of bits in the second reserve field.

[0152] In the embodiment of the present application, the amount of scrambling code information carried in the RAR is associated with the number of bits in the reserve field.

[0153] For example, as shown in FIG8 , if the subcarrier spacing of the random access preamble is 15 kHz, the first reserved field is reserved field 801, and the second reserved field is reserved field 802. Reserved field 801 includes 5 bits, and reserved field 802 includes 1 bit. Reserved field 801 can indicate 32 scrambling code information, and reserved field 802 can indicate 2 scrambling code information. Reserved field 801 and reserved field 802 can jointly indicate 64 scrambling code information.

[0154] Alternatively, as shown in FIG9 , if the subcarrier spacing of the random access preamble is 3.75 kHz, the first reserved field is reserved field 901, and the second reserved field is reserved field 902. Reserved field 901 includes 3 bits, and reserved field 902 includes 1 bit. Thus, reserved field 901 can indicate 8 scrambling code information, and reserved field 902 can indicate 2 scrambling code information. Reserved field 901 and reserved field 902 can jointly indicate 16 scrambling code information.

[0155] S704: Receive a random access response from the network device.

[0156] The random access response received by the terminal carries the second scrambling code information.

[0157] Based on the above technical solution, not only does the random access preamble sent by the terminal to the network device carry scrambling code information, but the RAR sent back by the network device also carries scrambling code information, allowing the terminal to receive the RAR carrying the scrambling code information. In this way, when the time-frequency resources used to send the random access preamble and the random access preamble are the same, the terminal can use the scrambling code information to find the RAR sent back to it and use the corresponding uplink resources to send MSG3, thereby increasing the number of terminals accessing the network.

[0158] The above describes the process of receiving and sending a random access preamble carrying scrambling code information and a RAR carrying scrambling code information. After a terminal receives a RAR carrying second scrambling code information, it can determine whether the RAR is a reply to itself based on the second scrambling code information. The following describes the process by which a terminal determines whether the RAR is a reply to itself.

[0159] It should be noted that in the embodiment of the present application, the network device can generate a RAR carrying the second scrambling code information using method 1 (scrambling using the second scrambling code information) or method 2 (indicating the second scrambling code information through a MAC CE). That is, the location of the second scrambling code information in the RAR is different. Therefore, after receiving the RAR, the terminal can determine whether the RAR is a RAR for the terminal based on the second scrambling code information in different ways.

[0160] In an embodiment of the present application, when the network device uses the second scrambling code information to scramble the PDCCH portion in the RAR, the terminal can determine whether the RAR is the RAR replying to the terminal based on the second RA-RNTI and the second random access preamble identifier. The second RA-RNTI is determined based on the first scrambling code information, and the second random access preamble identifier is the identifier of the random access preamble sent by the terminal.

[0161] That is, in the first approach, the second RA-RNTI is determined based on the first scrambling code information.

[0162] As shown in FIG10 , a random access method is provided for an embodiment of the present application. In the random access method, S704 may include:

[0163] S1001. Use the second RA-RNTI to monitor the physical downlink control channel.

[0164] In this embodiment of the present application, the PDCCH is scrambled by the first RA-RNTI, where the first RA-RNTI is determined based on the second scrambling code information.

[0165] That is, when the second scrambling code information is used to scramble the PDCCH part in the RAR (ie, method 1), the PDCCH part in the RAR carries the second scrambling code information.

[0166] S1002: Determine whether the second RA-RNTI can be used to descramble the PDCCH.

[0167] If the first RA-RNTI and the second RA-RNTI are the same, the terminal may determine that the PDCCH is successfully descrambled using the second RA-RNTI.

[0168] In one possible implementation, the terminal may determine whether the first scrambling code information in the second RA-RNTI is the same as the second scrambling code information in the first RA-RNTI. If the first scrambling code information and the second scrambling code information are the same, the terminal determines that PDCCH descrambling using the second RA-RNTI is successful. If the first scrambling code information and the second scrambling code information are different, the terminal determines that PDCCH descrambling using the second RA-RNTI has failed.

[0169] Optionally, the second RA-RANTI is determined based on the first scrambling code information and the time-frequency information for sending the random access preamble. The terminal can determine whether the first scrambling code information in the second RA-RNTI is the same as the second scrambling code information in the first RA-RNTI, and whether the time-frequency information in the second RA-RANTI is the same as the time-frequency information in the first RA-RANTI. If the first scrambling code information is the same as the second scrambling code information, and the time-frequency information in the second RA-RANTI is the same as the time-frequency information in the first RA-RANTI, the terminal determines that the PDCCH descrambling is successful using the second RA-RNTI. If the first scrambling code information is different from the second scrambling code information, and / or the time-frequency information in the second RA-RANTI is different from the time-frequency information in the first RA-RANTI, the terminal determines that the PDCCH descrambling using the second RA-RNTI has failed.

[0170] In some embodiments, if the PDCCH is successfully descrambled using the second RA-RNTI, the terminal executes S1003.

[0171] In some embodiments, if the second RA-RNTI fails to descramble the PDCCH, the terminal re-executes S1001, i.e., continues to monitor the PDCCH using the second A-RNTI. If the terminal fails to descramble the PDCCH within a first preset period, S1001 is stopped. The first preset period is a random access response window (RAR window).

[0172] It is understood that the terminal can monitor the PDCCH using the second RA-RNTI determined based on the first scrambling code information. In this way, the terminal can determine whether the RAR is a response to the first scrambling code information based on the second RA-RNTI. If PDCCH descrambling fails using the second RA-RNTI, it indicates that the RAR is not a response to the first scrambling code information. The terminal can continue to monitor the PDCCH using the second RA-RNTI to find a response to the first scrambling code information.

[0173] S1003: Obtain a first random access preamble identifier in the RAR.

[0174] In an embodiment of the present application, after the terminal descrambles the PDCCH using the second RA-RNTI, the terminal can obtain RAR scheduling information. The scheduling information may include: PDSCH transmission parameters. The PDSCH transmission parameters include: the format for transmitting the PDSCH, the time-frequency information for transmitting the PDSCH, the modulation and coding scheme, etc. The terminal can then receive RAR information on the PDSCH based on the PDSCH transmission parameters. The RAR information includes: a first random access preamble identifier, and the first random access preamble identifier corresponds to the RAR information. The terminal can then obtain the first random access preamble identifier from the RAR.

[0175] S1004: Determine whether the first random access preamble identifier is the same as the second random access preamble identifier.

[0176] In some embodiments, if the first random access preamble identifier is the same as the second random access preamble identifier, the terminal executes S1004.

[0177] For example, if the first random access preamble identifier in the RAR is rapid and the second random access preamble identifier is preamble index, if rapid and preamble index are the same, the terminal executes S1005.

[0178] In some embodiments, if the first random access preamble identifier is different from the second random access preamble identifier, the terminal re-executes S1001, that is, continues to monitor the PDCCH using the second A-RNTI. If the terminal fails to successfully descramble the PDCCH within the first preset time period, the terminal stops executing S1001.

[0179] It is understandable that the terminal can monitor the PDCCH using the second RA-RNTI determined based on the first scrambling code information. In this way, the terminal can determine whether the RAR is a response to the first scrambling code information based on the second RA-RNTI. If the PDCCH is successfully descrambled using the second RA-RNTI, but the first random access preamble identifier and the second random access preamble identifier are different, it means that the RAR is a response to the first scrambling code information, but the subcarriers are different. In this case, the terminal can continue to monitor the PDCCH using the second RA-RNTI to find a response to the first scrambling code information.

[0180] S1005: Determine that the RAR is the RAR of the reply terminal.

[0181] In the embodiment of the present application, if the PDCCH is successfully descrambled using the second RA-RNTI, and the first random access preamble identifier is the same as the second random access preamble identifier, the terminal determines that the RAR information corresponding to the first random access preamble identifier is the RAR information replied to the terminal.

[0182] Based on the above solution, the terminal can monitor the PDCCH using the second RA-RNTI determined based on the first scrambling code information. This allows the terminal to determine, based on the second RA-RNTI, whether the RAR is a response to the first scrambling code information. If the PDCCH is successfully descrambled using the second RA-RNTI, it indicates that the RAR is a response to the first scrambling code information. The terminal can then use the first and second random access preamble identifiers to determine whether the RAR is a response to the terminal. This ensures that terminals using different scrambling code information receive different RARs, reducing random access conflicts and contention and increasing the number of terminals actually accessing the network.

[0183] For example, if UE1 and UE2 are on the same UL carrier, select the same preamble, and transmit the preamble in the same time domain, but UE1 selects a different scrambling code, UE1 and UE2 can use different RA-RNTIs to monitor the PDCCH. The base station can also use different PDCCHs and schedule different RARs to respond to UE1 and UE2 respectively. In this way, UE1 and UE2 can obtain different RARs and use different resources to transmit MSG3, without causing any conflict between UE1 and UE2.

[0184] The above describes how a terminal determines whether the RAR is the RAR intended for the terminal when the network device uses the second scrambling code information to scramble the PDCCH portion of the RAR (i.e., Method 1). The following describes how a terminal determines whether the RAR is the RAR intended for the terminal when the network device indicates the second scrambling code information via a MAC CE (i.e., Method 2).

[0185] In an embodiment of the present application, when the network device indicates the second scrambling code information through the MAC CE, the terminal can determine whether the RAR is the RAR replied to the terminal according to the second RA-RNTI, the second random access preamble identifier and the first scrambling code information.

[0186] That is, when the second scrambling code information is indicated by the MAC CE, the second RA-RNTI is not determined based on the first scrambling code information.

[0187] As shown in FIG11 , a random access method is provided for an embodiment of the present application. In the random access method, S704 may include:

[0188] S1101. Use the second RA-RNTI to monitor the physical downlink control channel.

[0189] It should be noted that, for the specific introduction of S1101, reference may be made to the description of S1001 in the above embodiment, which will not be repeated here.

[0190] S1102: Determine whether the second RA-RNTI can be used to descramble the PDCCH.

[0191] The PDCCH is scrambled by the first RA-RNTI.

[0192] In one possible design, the first RA-RNTI is determined based on time-frequency information.

[0193] That is, the first RA-RNTI is determined based on the time-frequency information, but not based on the second scrambling code information.

[0194] It should be understood that if the first RA-RNTI is determined based on the time-frequency information, the second RA-RNTI is also determined based on the time-frequency information and is not determined based on the first scrambling code information.

[0195] In another possible design, the first RA-RNTI is determined based on the second scrambling code information and the time-frequency information.

[0196] It should be understood that if the first RA-RNTI is determined based on the second scrambling code information and the time-frequency information, the second RA-RNTI is determined based on the first scrambling code information and the time-frequency information.

[0197] It should be noted that for the case where the first RA-RNTI is determined by the second scrambling code information and the time-frequency information, and the second RA-RNTI is determined by the first scrambling code information and the time-frequency information, reference can be made to the description in the above embodiment S1002, and no further description is given here. The following describes the case where the first RA-RNTI is determined based on the time-frequency information and not based on the second scrambling code information.

[0198] In one possible implementation, the terminal may determine whether the time-frequency information in the second RA-RANTI is the same as the time-frequency information in the first RA-RANTI. If the time-frequency information in the second RA-RANTI is the same as the time-frequency information in the first RA-RANTI, the terminal determines that PDCCH descrambling using the second RA-RNTI is successful. If the time-frequency information in the second RA-RANTI is different from the time-frequency information in the first RA-RANTI, the terminal determines that PDCCH descrambling using the second RA-RNTI has failed.

[0199] In some embodiments, if the PDCCH is successfully descrambled using the second RA-RNTI, the terminal executes S1103.

[0200] In some embodiments, if the second RA-RNTI fails to descramble the PDCCH, the terminal re-executes S1101, ie, continues to monitor the PDCCH using the second A-RNTI. If the terminal fails to descramble the PDCCH within the first preset time period, the terminal stops executing S1101.

[0201] S1103: Receive MAC CE based on PDCCH.

[0202] In one possible implementation, after the terminal descrambles the PDCCH using the second RA-RNTI, the terminal may obtain scheduling information that instructs the terminal to receive and process data in the PDSCH portion. The terminal may then receive the PDSCH according to the scheduling information, the PDSCH including the MAC CE.

[0203] S1104. Obtain a first random access preamble identifier and second scrambling code information from the MAC CE.

[0204] In the embodiment of the present application, the RAR includes: a MAC CE, and the MAC CE includes: second scrambling code information.

[0205] Optionally, the MAC CE may further include: a first random access preamble identifier.

[0206] S1105: Determine whether the first random access preamble identifier is the same as the second random access preamble identifier.

[0207] It should be noted that in the NB-IoT system, the random access preamble has only a sequence consisting of all 1s. In other words, when the terminal selects the random access preamble, it actually selects the subcarrier that sent the random access preamble, that is, it still selects the frequency domain information that sent the random access preamble.

[0208] In the embodiment of the present application, one random access preamble identifier corresponds to one subcarrier identifier. That is, the random access preamble identifier can reflect frequency domain information.

[0209] It should be noted that, for an introduction to the terminal determining whether the first random access preamble identifier is the same as the second random access preamble identifier, reference may be made to the description in S1004 of the above embodiment, which will not be repeated here.

[0210] S1106: Determine whether the first scrambling code information is the same as the second scrambling code information.

[0211] It should be noted that the embodiment of the present application does not limit the order of executing S1105 and S1106. For example, the terminal may execute S1105 first and then execute S1106. For another example, the terminal may execute S1106 first and then execute S1105. For another example, the terminal may execute S1105 and S1106 simultaneously.

[0212] In some embodiments, if the first random access preamble identifier is the same as the second random access preamble identifier, and the first scrambling code information is the same as the second scrambling code information, the terminal executes S1107.

[0213] In some embodiments, if the first random access preamble identifier and the second random access preamble identifier are different, and / or the first scrambling code information and the second scrambling code information are different, the terminal determines that the RAR is not the RAR that responded to the terminal. The terminal then re-executes S1101, i.e., continues to monitor the PDCCH using the second A-RNTI. If the terminal fails to successfully descramble the PDCCH within the first preset time period, the terminal stops executing S1101.

[0214] S1107: Determine that the RAR is the RAR of the replying terminal.

[0215] In this embodiment of the present application, one RAR message corresponds to one random access preamble identifier and one scrambling code information. If the first random access preamble identifier and the second random access preamble identifier are the same, and the first scrambling code information and the second scrambling code information are the same, the terminal determines that the RAR message corresponding to the first random access preamble identifier and the second scrambling code information is the RAR message of the reply terminal.

[0216] Based on the above solution, after monitoring the PDCCH using the second RA-RNTI, the terminal can determine whether the RAR is intended for the terminal based on whether the first random access preamble identifier and the second random access preamble identifier are identical, and whether the first scrambling code information and the second scrambling code information are identical. In this way, the terminal can determine whether the RAR is intended for the terminal based on both code domain information and frequency domain information. This ensures that terminals using different scrambling code information receive different RARs, reducing random access conflicts and contention, and increasing the number of terminals actually accessing the network.

[0217] For example, if UE1 and UE2 are on the same UL carrier and select the same preamble and send the preamble in the same time domain, but UE1 selects a different scrambling code, UE1 and UE2 can use the same RA-RNTI (obtained based on time-frequency information) to monitor the PDCCH and receive the MAC CE. The MAC CE in the RAR includes not only the preamble ID but also scrambling code information (such as the OCC ID). This allows UE1 and UE2 to obtain different RARs using different OCC IDs and use different resources to send MSG3.

[0218] In some embodiments, after the terminal determines that the RAR is the RAR that replies to the terminal, the terminal may use the uplink resources in the RAR to send Msg3 to the network device. Correspondingly, the network device may receive Msg3 from the terminal.

[0219] The RAR includes uplink resources, which are resources corresponding to a UL Grant. The UL Grant is used to indicate the time and format of uplink data sent by the terminal on specific resources.

[0220] In a possible implementation, the terminal may adjust the timing of sending uplink data according to the TA carried in the RAR, and use the uplink resources in the RAR to send Msg3, where Msg3 includes: a terminal identifier and a TC-RNTI of the terminal.

[0221] Exemplarily, the terminal identifier may be an S-TMSI.

[0222] It is understandable that after the terminal determines that the RAR is the RAR that responds to the terminal through the scrambling code information, the terminal can use the uplink resources in the RAR to send Msg3 to the network device to complete the random access process.

[0223] In some embodiments, after receiving Msg3 from the terminal, the network device may determine whether to allow the terminal to access. If the terminal is allowed to access, the network device may send Msg4, which includes the terminal identifier. Msg4 is used to indicate that the terminal contention has been successfully resolved.

[0224] That is, after receiving Msg4, the terminal can access the network. At the same time, the terminal's TC-RNTI is upgraded to a Cell-Radio Network Temporary Identifier (C-RNTI), and the terminal can use the C-RNTI for subsequent data and signaling transmission and reception in the cell.

[0225] As shown in FIG12 , a random access method is provided for an embodiment of the present application. The random access method may include:

[0226] S1201: Send a random access preamble carrying first scrambling code information to a network device.

[0227] S1202: Receive a random access response from the network device.

[0228] The RAR carries the second scrambling code information.

[0229] It should be noted that, for the specific introduction of S1201-S1202, reference may be made to the introduction of S701 and S703 in the above embodiment, which will not be repeated here.

[0230] Based on the above technical solution, not only does the random access preamble sent by the terminal to the network device carry scrambling code information, but the terminal can also receive the RAR that also carries the scrambling code information. In this way, when the time-frequency resources used to send the random access preamble and the random access preamble are the same, the terminal can find the RAR sent back to it based on the scrambling code information and use the corresponding uplink resources to send MSG3, thereby increasing the number of terminals accessing the network.

[0231] As shown in FIG13 , a random access method is provided for an embodiment of the present application. The random access method may include:

[0232] S1301. Receive a random access preamble from a terminal.

[0233] The random access preamble carries first scrambling code information.

[0234] S1302: Send a random access response to the terminal.

[0235] The RAR carries the second scrambling code information.

[0236] It should be noted that, for the specific introduction of S1301-S1302, reference may be made to the introduction of S702 and S704 in the above embodiment, which will not be repeated here.

[0237] Based on the above technical solution, after receiving a random access preamble carrying the first scrambling code information, the network device can also transmit the RAR message back to the terminal containing the scrambling code information, allowing the terminal to receive the RAR message containing the scrambling code information. In this way, when the time-frequency resources used to transmit the random access preamble and the random access preamble are the same, the terminal can find the RAR message sent to it based on the scrambling code information and use the corresponding uplink resources to send Msg3, thereby increasing the number of terminals accessing the network.

[0238] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the terminal and the network device. It is understandable that, in order to implement the above functions, the terminal and the network device include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the steps of a random access method of each example described in the embodiment disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in hardware or in a manner where the terminal and network device software drives the hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0239] In the embodiments of the present application, the random access device can be divided into functional modules or functional units according to the above-mentioned method examples. For example, each functional module or functional unit can be divided according to each function, or two or more functions can be integrated into a processing module. The above-mentioned integrated modules can be implemented in the form of hardware or software functional modules or functional units. The division of modules or units in the embodiments of the present application is illustrative and is only a logical functional division. In actual implementation, other division methods may be used.

[0240] Other embodiments of the present application provide a terminal comprising: a processor coupled to a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory to cause the terminal to perform the functions and steps described in the embodiments above.

[0241] Other embodiments of the present application provide a network device, comprising: a processor coupled to a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory, causing the network device to perform the functions and steps described above.

[0242] An embodiment of the present application also provides a chip system, as shown in Figure 14, which includes at least one processor 1401 and at least one interface circuit 1402. The processor 1401 and the interface circuit 1402 can be interconnected via lines. For example, the interface circuit 1402 can be used to receive signals from other devices (such as the memory of the terminal). For another example, the interface circuit 1402 can be used to send signals to other devices (such as the processor 1401). Exemplarily, the interface circuit 1402 can read instructions stored in the memory and send the instructions to the processor 1401. When the instructions are executed by the processor 1401, the terminal can execute the various steps in the above embodiments. Of course, the chip system can also include other discrete devices, which is not specifically limited in the embodiment of the present application.

[0243] An embodiment of the present application further provides a computer-readable storage medium, which includes computer instructions. When the computer instructions are executed on the above-mentioned terminal, the terminal executes the various functions or steps executed by the terminal in the above-mentioned method embodiment.

[0244] An embodiment of the present application also provides a computer-readable storage medium, which includes computer instructions. When the computer instructions are executed on the above-mentioned network device, the network device executes each function or step executed by the network device in the above-mentioned method embodiment.

[0245] An embodiment of the present application further provides a computer program product, which, when executed on a computer, enables the computer to execute the functions or steps executed by the terminal or network device in the above method embodiment.

[0246] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0247] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0248] The units described as separate components may or may not be physically separate, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple places. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0249] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0250] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0251] The above content is only a specific embodiment of this application, but the scope of protection of this application is not limited to this. Any changes or replacements within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A random access method, characterized in that: Applied to a terminal, the method includes: Sending a random access preamble carrying first scrambling code information to a network device; Based on the first scrambling code information, a random access response RAR is received from the network device, where the RAR carries second scrambling code information.

2. The method according to claim 1, characterized in that The RAR includes: a physical downlink control channel PDCCH scrambled by using a first random access identification code RA-RNTI; the first RA-RNTI is determined based on the second scrambling code information.

3. The method according to claim 2, characterized in that The first RA-RNTI is determined based on the second scrambling code information and time-frequency information.

4. The method according to claim 2 or 3, characterized in that The number of bits occupied by the second scrambling code information in the first RA-RNTI is higher than the number of bits occupied by the time-frequency information in the first RA-RNTI.

5. The method according to any one of claims 2 to 4, characterized in that The receiving, based on the first scrambling code information, a random access response RAR from the network device includes: Using a second RA-RNTI, monitoring the PDCCH; the second RA-RNTI is determined based on the first scrambling code information; If the PDCCH is successfully descrambled using the second RA-RNTI, obtaining a first random access preamble identifier in the RAR; If the first random access preamble identifier is the same as the second random access preamble identifier, it is determined that the RAR is the RAR replied to the terminal, and the second random access preamble identifier is the identifier of the random access preamble sent by the terminal.

6. The method according to claim 5, characterized in that The method further comprises: If the PDCCH is successfully descrambled using the second RA-RNTI, and the first random access preamble identifier is different from the second random access preamble identifier, the second RA-RNTI is continued to be used to monitor the PDCCH.

7. The method according to claim 5 or 6, characterized in that The method further comprises: If descrambling of the PDCCH using the second RA-RNTI fails, continuing to monitor the PDCCH using the second RA-RNTI.

8. The method according to any one of claims 1 to 4, characterized in that The RAR includes: a media access control layer control element MAC CE, and the MAC CE includes: the second scrambling code information.

9. The method according to claim 8, characterized in that The MAC CE further includes: a first random access preamble identifier, where the first random access preamble identifier is used to indicate frequency domain information for sending the random access preamble.

10. The method according to claim 8 or 9, characterized in that The receiving, based on the first scrambling code information, a random access response RAR from the network device includes: Use the second RA-RNTI to monitor the PDCCH; If the PDCCH is successfully descrambled using the second RA-RNTI, receiving the MAC CE based on the PDCCH; Acquire the first random access preamble identifier and the second scrambling code information from the MAC CE; If the first random access preamble identifier is the same as the second random access preamble identifier, and the first scrambling code information is the same as the second scrambling code information, it is determined that the RAR is the RAR replied to the terminal, and the second random access preamble identifier is the identifier of the random access preamble sent by the terminal.

11. The method according to claim 5 or 10, characterized in that If the first RA-RNTI is the same as the second RA-RNTI, the PDCCH is successfully descrambled using the second RA-RNTI.

12. The method according to any one of claims 1 to 11, characterized in that The RAR further includes: uplink resources; the method further includes: A third message Msg3 is sent to the network device using the uplink resource in the RAR.

13. The method according to any one of claims 1 to 12, characterized in that The method further comprises: Acquire scrambling code configuration information, where the scrambling code configuration information includes: at least one scrambling code and the number of scrambling codes.

14. The method according to any one of claims 1 to 13, characterized in that The scrambling code is the orthogonal cover code OCC.

15. A random access method, characterized in that: Applied to a network device, the method includes: receiving a random access preamble from a terminal, where the random access preamble carries first scrambling code information; A random access response RAR is sent to the terminal, where the RAR carries second scrambling code information.

16. The method according to claim 15, characterized in that The RAR includes: a physical downlink control channel PDCCH scrambled by using a first random access identifier RA-RNTI, where the first RA-RNTI is determined based on the second scrambling code information.

17. The method according to claim 15 or 16, characterized in that The first RA-RNTI is determined based on the second scrambling code information and time-frequency information.

18. The method according to claim 16 or 17, characterized in that The number of bits occupied by the second scrambling code information in the first RA-RNTI is higher than the number of bits occupied by the time-frequency information in the first RA-RNTI.

19. The method according to any one of claims 15 to 18, characterized in that The RAR includes: a media access control layer control element MAC CE, and the MAC CE includes: the second scrambling code information.

20. The method according to claim 19, characterized in that The MAC CE further includes: a first random access preamble identifier, where the first random access preamble identifier is used to indicate frequency domain information for sending the random access preamble.

21. The method according to any one of claims 15 to 20, characterized in that The RAR further includes: uplink resources; the method further includes: A third message Msg3 is received from the terminal.

22. The method according to any one of claims 15 to 21, characterized in that The method further comprises: Broadcast scrambling code configuration information, where the scrambling code configuration information includes: at least one scrambling code and the number of scrambling codes.

23. The method according to any one of claims 15 to 22, characterized in that The scrambling code is the orthogonal cover code OCC.

24. A terminal, characterized in that: The terminal includes: a processor coupled to a memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so that the terminal performs the method according to any one of claims 1 to 14.

25. A network device, characterized in that: The network device includes: a processor coupled to a memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so that the network device performs the method according to any one of claims 15 to 23.

26. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a computer program or instructions, which, when executed on a computer, causes the computer to perform the method according to any one of claims 1 to 23.

27. A computer program product, characterized in that The computer program product comprises: a computer program or instructions, and when the computer program or instructions are run on a computer, the computer is caused to perform the method according to any one of claims 1 to 23.

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