Random access method and communication device

Abstract

The invention discloses a random access method and a communication device, and the method comprises the steps: determining a first index difference value under the condition that the reason of random access failure is lead code mismatching, the first index difference value is a difference value between a first index and a second index, the first index is an index of a sent first lead code, and the second index is an index of a sent second lead code; the second index is a lead code index in the received response message; and sending the first lead code to the network equipment based on the first index difference value. By adopting the method, the success probability of random access can be improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a random access method and a communication device. Background Art

[0002] If a terminal device wants to access a cell, it needs to go through a random access process. The random access process mainly includes the following steps: the terminal device sends a first message msg1 containing a preamble to the network device; after receiving msg1, the network device responds to msg1 and sends a response message msg2 to the terminal device (msg2 contains the index of the preamble index). After the terminal device receives msg2 containing the index of the preamble it sent, it can successfully perform subsequent random access operations.

[0003] However, for long-distance access (the physical distance between the network device and the terminal device is far), the following situation may occur: the terminal device sends the first message msg1 containing the preamble to the network device; however, due to the delay caused by the physical distance, the preamble actually received by the network device is different from the preamble sent by the terminal device, and the network device mistakes the preamble for another preamble. The preamble index in msg2 sent by the network device to the terminal device is different from the index corresponding to the preamble in msg1. The terminal device believes that it has not received the msg2 corresponding to the msg1 it sent, which will cause random access failure.

[0004] For example, suppose the terminal device selects preambleA with a preamble index of 61, and the msg1 sent by the terminal device to the network device contains preambleA. However, due to the delay caused by the physical distance, the preamble code recognized by the network device becomes preambleB, and the preamble index corresponding to preambleB is 59. Therefore, the preamble index contained in mgs2 sent by the network device to the terminal device is 59. The terminal device finds that the preamble index in the received msg2 is 59, not 61, and the terminal device believes that it has not received the corresponding msg2. As a result, random access fails. Summary of the invention

[0005] The present application provides a random access method and a communication device, which can improve the success probability of random access.

[0006] In a first aspect, some embodiments of the present application provide a random access method. The random access method may include: when the reason for the random access failure is that the preamble code does not match, determining a first index difference value, the first index difference value is the difference between a first index and a second index, the first index is the index of the first preamble code sent, and the second index is the preamble code index in the received response message; based on the first index difference value, sending the first preamble code to the network device.

[0007] By the above method, the first preamble is sent in advance to offset the delay between the terminal device and the network device, so that the sequence received by the network device is complete, avoiding the network device mistaking the received sequence for other preambles, thereby avoiding random access failure caused by preamble mismatch. The method of sending the first preamble in advance can increase the probability of successful random access.

[0008] In a possible embodiment, sending a first preamble code to a network device based on a first index difference value includes: determining an advance time amount based on the first index difference value; and sending the first preamble code in advance based on the advance time amount.

[0009] In a possible embodiment, determining the advance time based on the first index difference includes: when the cause of N consecutive random access failures is preamble code mismatch, determining the advance time based on the first index difference, where N is a positive integer greater than 0.

[0010] In a possible embodiment, when the cause of N consecutive random access failures is preamble code mismatch, the advance time amount is determined based on the first index difference, including: when the cause of N consecutive random access failures is preamble code mismatch, and the index differences under N consecutive random access failures are all within a preset range, the advance time amount is determined based on the first index difference.

[0011] In a possible embodiment, determining the advance time based on the first index difference includes: determining the advance time based on the first index difference, the sequence length of the first preamble code, the unit cyclic shift amount of the first preamble code, and the subcarrier spacing.

[0012] In a possible embodiment, after sending the first preamble code in advance based on the advance time amount, the method further includes: if the random access fails, adding the cell corresponding to the network device to a blacklist.

[0013] In a possible embodiment, if random access fails, the cell corresponding to the network device is added to a blacklist. The method further includes: if random access fails and the number of random access failures is greater than a preset threshold, the cell corresponding to the network device is added to a blacklist.

[0014] In a second aspect, the present application provides a communication device, for example, the communication device may be a module of a terminal device such as a processor, a chip, or a chip system, and may also be a logical node, a logical module, or software that can implement all or part of the functions of the terminal device. The communication device includes a module / unit for executing any method in the first aspect and its possible implementations.

[0015] In a third aspect, the present application provides a communication device, including a processor, wherein the processor is coupled to a memory, and the memory is used to store programs or instructions. When the program or instructions are executed by the processor, the device executes the method described in the first aspect above.

[0016] In a fourth aspect, the present application provides a chip, comprising a processor and an interface, wherein the processor and the interface are coupled; the interface is used to receive or output signals, and the processor is used to execute code instructions, so that the chip executes the method described in the first aspect above.

[0017] In a fifth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called, the method described in the first aspect is executed.

[0018] In a sixth aspect, the present application provides a computer program product, comprising: a computer program code, wherein when the computer program code is executed, the method described in the first aspect is executed.

[0019] In a seventh aspect, the present application provides a communication system, which includes a communication device for executing the method described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A A schematic diagram of a communication system provided in an embodiment of the present application; Figure 1B A schematic diagram of another communication system provided in an embodiment of the present application; Figure 1C A schematic diagram of the principle of misidentifying a preamble provided in an embodiment of the present application; Figure 2 A schematic diagram of a random access method provided in an embodiment of the present application; Figure 3A A schematic diagram of a random access failure provided in an embodiment of the present application; Figure 3B A schematic diagram of another random access method provided in an embodiment of the present application; Figure 3C A schematic diagram of another random access method provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a communication device provided by the present application; Figure 5 A schematic diagram of the structure of another communication device provided in this application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0022] It should be understood that the terms "first", "second", etc. in the specification, claims and drawings of the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0023] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0024] In order to better understand the present application, the random access process involved in the present application is first introduced below. The random access process is divided into two types: contention-based random access and non-contention-based random access.

[0025] Contention-based random access mainly includes the following steps: First, the terminal device randomly selects a preamble from the contention-based preamble pool shared with other terminal devices in the cell.

[0026] The terminal device sends Msg1 to the network device: the Msg1 includes a preamble randomly selected by the terminal device from a preamble pool.

[0027] The network device sends Msg2 to the terminal device: After the network device detects the preamble sent by the terminal device, it sends a random access response (Mg2), which includes the preamble index.

[0028] The terminal device sends Msg3 to the network device: After the terminal device detects its own random access response (the preamble index contained in Msg2 is the same as the index corresponding to the preamble in Msg1), it uses the allocated resources to send a high-level signaling message, that is, it sends Msg3 according to the time-frequency resource position configured in Msg2.

[0029] The network device sends Msg4 to the terminal device: The network device sends a conflict resolution response. The terminal device determines whether the competition is successful.

[0030] Non-contention-based random access mainly includes the following steps: First, the network device allocates a specific preamble to the terminal device according to the requirements. The network device can inform the terminal device of the specific preamble through Msg0.

[0031] The terminal device sends Msg1 to the network device: the Msg1 contains a specific preamble assigned by the network device.

[0032] The network device sends Msg2 to the terminal device: After the network device detects the preamble sent by the terminal device, it sends a random access response.

[0033] Whether it is contention-based random access or non-contention-based random access, preamble is crucial. According to the NR protocol or LTE protocol, the preamble is constructed by a cyclically shifted ZC sequence:

[0034]

[0035] in, Indicates the length u is the physical root sequence number, which is obtained by looking up the protocol table with the logical root sequence number. is the length of the ZC sequence, which can be 139 or 839.

[0036] in, Indicates preamble, is the vth cyclic shift amount, the Satisfies the following formula:

[0037] in, It is the unit cyclic shift amount and is configured by higher layers.

[0038] It can be seen from the above three formulas that by performing different cyclic shifts on the ZC sequence, multiple preambles will be obtained. In the cell's preamble pool, there are 64 preambles (obtained by performing different cyclic shifts on multiple root sequences) for terminal devices to select to initiate random access (as described in the above contention-based random access). Among them, the 64 preambles are determined by: starting from the initial root index configured by the high-level layer, for each ZC sequence corresponding to the logical root index (or called root sequence), each cyclic shift ( ) is recorded as 1 preamble. When the maximum cyclic shift is reached, the ZC sequence corresponding to the next logical root index is determined, and each cyclic shift on the ZC sequence ( ) is recorded as 1 preamble, and so on, until 64 preambles are determined.

[0039] For example, it is assumed that the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1] (in actual cases, the length of the ZC sequence is much longer than this, and this sequence is only used for example convenience). is 2, that is, the unit cyclic shift amount is 2. When the ZC sequence is cyclically shifted, it is in units of two bits. For example, after a cyclic shift of the ZC sequence, [0 1 1 1 0 1 11 1 0] ([ 1 0 0 1 1 1 0 1 1 1]—>[0 1 1 1 0 1 1 1 1 0 ]), [0 1 1 1 0 1 1 1 1 0] is the obtained preamble. After performing two cyclic shifts on the ZC sequence, we get [1 1 0 1 1 1 1 0 0 1] ([ 1 0 0 1 1 1 0 1 1 1]—>[1 1 0 1 1 1 1 0 0 1 ]), [1 1 0 1 1 1 1 0 0 1] is another preamble obtained. And so on.

[0040] From the perspective of the Physical Random Access Channel (PRACH), Determines the coverage distance of PRACH. When a terminal device sends a preamble from a location beyond the coverage range of PRACH, the network device will mistake the preamble for another preamble.

[0041] For example, assuming that the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1], the preamble 1 sent by the terminal device is [1 1 0 1 1 1 1 0 0 1] ([ 1 0 0 1 1 1 0 1 1 1]—>[1 1 0 1 1 1 1 0 0 1 ]).

[0042] When the terminal device sends preamble 1 at a location covered by PRACH, it can be considered that there is no delay between the network device and the terminal device. At this time, the network device receives the preamble 1 in the corresponding window. The network device receives the complete preamble 1 and carries the index corresponding to the preamble 1 in Msg2 to feed back to the terminal device, so that the terminal device can perform subsequent random access operations.

[0043] However, when the terminal device sends preamble 1 at a location beyond the PRACH coverage, there is a delay between the network device and the terminal device, such as Figure 1C As shown, the network device should receive the first symbol of preamble1 at the first position of the preamble window, and the second symbol of preamble1 at the second position of the preamble window. And so on, the entire preamble1 is received. However, due to the delay, the preamble is delayed in reaching the network device, and the network device does not receive the symbol at the first position of the preamble window, nor does it receive the symbol at the second position of the preamble window. The network device receives the first symbol of preamble1 at the third position of the preamble window. Since the length of the window is fixed and the first two positions of the window do not carry symbols, the final received sequence loses the last two symbols of preamble1, and the incomplete sequence received by the network device is [1 1 0 1 1 1 1 0].

[0044] The network device autocorrelates the incomplete sequence with the preset ZC sequence (root sequence), that is, autocorrelates [1 1 01 1 1 0] and [1 0 0 1 1 1 0 1 1 1], and recognizes the incomplete sequence as preamble 2 [0 1 1 1 0 1 1 1 1 0 ]. preamble2[0 1 1 1 0 1 1 1 1 0] and the preamble1[1 1 0 1 1 1 sent by the terminal device 1 0 0 1 ] Obviously different, preamble2 has fewer cyclic shifts than preamble1, and the index corresponding to preamble2 is smaller than the index corresponding to preamble1. The network device carries the index corresponding to preamble2 in Msg2 and feeds it back to the terminal device. The terminal device finds that the index in the received Msg2 is not the index corresponding to the preamble1 it sent, so the terminal device resends Msg1 carrying preamble1 to the network device. Similarly, the network device will still mistake preamble1 for preamble2 due to latency issues. For the terminal device, it has been unable to receive Msg2 containing the index of the preamble1 it sent. Until the maximum number of preamble transmissions is reached, random access fails.

[0045] That is to say, due to the long distance between the terminal device and the network device, the preamble sent by the terminal device and the preamble recognized by the network device are not aligned, resulting in random access failure.

[0046] In order to solve the above problems and improve the success probability of random access, the present application provides a random access method. A first preamble is sent to a network device through a first index difference, so that the network device can receive preamble 1 from the first symbol, so that the preamble sent by the terminal device and the preamble considered by the network device are aligned, thereby avoiding the problem of random access failure caused by the network device misidentifying the preamble, thereby improving the success probability of random access.

[0047] In order to better understand the embodiments of the present application, the communication system involved in the present application is first introduced below.

[0048] First of all, the network device involved in this application refers to a device that can communicate with a terminal device.

[0049] The terminal device involved in this application is an entity on the user side that is used to receive signals, or send signals, or receive and send signals. The terminal device is used to provide one or more of voice services and data connectivity services to users. The terminal device may be a device that includes wireless transceiver functions and can cooperate with network equipment to provide communication services to users. Specifically, the terminal device may refer to: user equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, terminal, wireless communication equipment, user agent, user device or road side unit (RSU). The user equipment may also be a drone, an Internet of Things (IoT) device, a station (ST) in a wireless local area network (WLAN), a cellular phone, a smart phone, a cordless phone, a wireless data card, a tablet computer, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a laptop computer, a machine type communication (MTC) terminal, a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device (also called a wearable smart device), a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in remote medical, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in smart grid, a transportation security (TRANSPORTATION) system, a wearable device (also called a wearable smart device), a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in remote medical, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in smart grid, a wireless terminal in transportation security (TRANSPORTATION) system ... remote medical, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in smart grid, a wireless terminal in transportation security (TRANSPORTATION) system, a wireless terminal in self driving, a wireless terminal in smart grid, a wireless terminal in transportation security (TRANSPORTATION) system, a wireless terminal in self driving, a wireless terminal in smart grid, a wireless terminal in transportation security (TRANSPORTATION) system, a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted The user equipment may be a wireless terminal in a 5G system or a terminal in a next-generation communication system, which is not limited in the embodiments of the present application.

[0050] The embodiments of the present application do not limit the device form of the user equipment. The device for implementing the function of the user equipment may be the user equipment; or it may be a device that can support the user equipment to implement the function, such as a chip system. The device may be installed in the user equipment or used in combination with the user equipment. In the embodiments of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices.

[0051] Network equipment: an entity on the network side that is used to send signals, or receive signals, or both send and receive signals. A network equipment may be a device deployed in a radio access network (RAN) to provide wireless communication functions for user equipment.

[0052] In one possible scenario, the network device may be a device with base station functions, such as an evolved NodeB (eNodeB), a transmission and receiving point (TRP), a transmission point (TP), a next generation NodeB (gNB), a next generation base station in a 6G mobile communication system, an integrated access and backhaul (IAB) node, a non-ground network device, that is, a device that can be deployed on a high-altitude platform or a satellite, etc. The network device may be a transmission reception point (TRP), a base station, or various forms of control nodes. For example, a network controller, a wireless controller, etc. Specifically, the network equipment can be various forms of macro base stations, micro base stations (also called small stations) in heterogeneous network (HetNet) scenarios, relay stations, access points (AP), radio network controllers (RNC), node B (NB), base station controllers (BSC), base transceiver stations (BTS), home base stations (e.g., home evolved nodeB, or home node B, HNB), baseband units (BBU) and remote radio units (RRU) in distributed base station scenarios, transmission points (TRP), transmitting points (TP), mobile switching centers, etc., and can also be antenna panels of base stations. The control node can connect to multiple base stations and configure resources for multiple terminals covered by multiple base stations. In systems using different wireless access technologies, the names of devices with base station functions may be different. For example, it may be the gNB in ​​5G, or the network-side equipment in the network after 5G, or the network equipment in the future evolved public land mobile network (communication) network (PLMN) network, or the equipment that performs the base station function in device-to-device (D2D) communication, machine-to-machine (M2M) communication, and Internet of Vehicles communication, etc. This application does not limit the specific name of the network equipment.The network equipment can also be the baseband pool (BBU pool) and RRU under the open access network (openRAN, O-RAN or ORAN), cloud radio access network (CRAN), etc.

[0053] In another possible scenario, multiple network devices collaborate to assist user equipment in achieving wireless access, and different network devices respectively implement part of the functions of the base station. For example, the network device may include a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU may be set separately, or may be included in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It is understandable that the network device may be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU may be divided into a network device in the access network RAN, or the CU may be divided into a network device in the core network CN, without limitation here.

[0054] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application takes CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0055] In the embodiments of the present application, the form of the network device is not limited. The device for realizing the function of the network device can be the network device; or it can be a device that can support the network device to realize the function, such as a chip system. The device can be installed in the network device or used in combination with the network device.

[0056] For example, Figure 1A As shown, Figure 1A A schematic diagram of an application scenario of an embodiment of the present application is shown in FIG. Figure 1A As shown, the application scenario may include a sending terminal device and a network device, wherein the network device may be any of the above-mentioned network devices, and correspondingly, the terminal device may be any of the above-mentioned terminal devices.

[0057] In a possible embodiment, the terminal device first sends a preamble to the network device for random access. If the random access fails and the reason for the failure is that the preamble does not match, the terminal device uses the access method provided by the present application to send the preamble to the network device again. Since the terminal device processes the process of sending the preamble again, the probability of successful random access can be improved.

[0058] For example, Figure 1B A schematic diagram of another application scenario provided by an embodiment of the present application, such as Figure 1B As shown, this scenario is illustrated by an example of a terminal device and two network devices. The relationship between the terminal device and the two network devices is as follows: the cell 2 (cell 2 corresponding to the network device 2) is the current service cell of the terminal device, the cell 1 (cell 1 corresponding to the network device 1) is the cell with good signal quality found by the terminal device, and the terminal device selects the cell 1 as the new service cell.

[0059] Depend on Figure 1B As shown, the terminal device is at the coverage edge of cell 2 (current service cell) and gradually leaves cell 2. Due to some network deployment reasons, the terminal device finds a cell with better signal quality, and the terminal device chooses to switch from cell 2 to cell 1. The reasons for the network deployment are, for example: the transmission power of cell 1 is higher than that of cell 2 and other cells nearby, or the antenna deployment heights of other cells near cell 2 are low, resulting in the signal being blocked by buildings around the terminal device, while the antenna deployment height of cell 1 is high, so that the model of cell 1 avoids the blockage of buildings around the terminal device.

[0060] However, since the physical distance between cell 1 and the terminal device is far, when the terminal device sends a preamble code to cell 1 to initiate a random access process, the delay caused by the physical distance will cause the network device to mistake the received preamble code for other preamble codes, thereby feeding back an incorrect preamble code index to the terminal device, and then causing random access failure due to the preamble code mismatch.

[0061] In order to solve this problem, the present application proposes a random access method. In the embodiment of the present application, the network device can be Figure 1B Network device 1 (cell 1) in.

[0062] In this scenario where the physical distance between the terminal device and the network device is far, Figure 1B In addition to the scenarios shown, it is also common in non-terrestrial network (NTN) scenarios.

[0063] As mentioned above, the technical solution of the present application can be applied to the NTN system, where NTN refers to a network or network segment that uses radio frequencies onboard satellites. In the NTN system, the communication link established between the user equipment and the satellite is called a service link, and the communication link established between the satellite and the network equipment is called a feeder link. The network equipment can transmit data with the satellite through the feeder link, and the user equipment can transmit data with the satellite through the service link. Alternatively, the technical solution of the present application can be applied to the scenario where NTN is integrated with the terrestrial network (TN).

[0064] The following is combined with Figure 2 The random access method provided in the embodiment of the present application is further introduced. It can be understood that the present application uses the terminal device and the receiving device as the execution subject of the interaction diagram as an example for illustration, but it does not limit the execution subject of the interaction diagram. For example, the method executed by the terminal device in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the terminal device, and can also be implemented by a logical node, a logical module or software that can realize all or part of the functions of the terminal device. Among them: 201. When the reason for the random access failure is that the preamble code does not match, the terminal device determines a first index difference, where the first index difference is a difference between a first index and a second index, the first index is an index of the first preamble code sent, and the second index is a preamble code index in the received response message; The first preamble is a preamble sent by the terminal device to the network device before the random access fails. The response message is a response message received by the terminal device from the network device before the random access fails.

[0065] In a possible embodiment, when the cause of random access failure of the terminal device is preamble code mismatch, before determining the first index difference, the method also includes: the terminal device sends the first preamble code to the network device; the terminal device receives a response message sent by the network device; the terminal device determines whether the cause of random access failure is preamble code mismatch based on the first preamble code and the response message.

[0066] The response message is a response message corresponding to the first preamble code, the first preamble code is carried in Msg1 and sent, and the response message includes the index of the preamble code. The response message is Msg2.

[0067] Optionally, the terminal device determines whether the cause of the random access failure is a preamble code mismatch based on the first preamble code and the response message, including: when the preamble code index in the response message is different from the index of the first preamble code, the terminal device determines that the cause of the random access failure is a mismatch.

[0068] Optionally, the terminal device sends a preamble code to the network device multiple times, and receives a response message multiple times.

[0069] Optionally, the second index is an index of the preamble code considered by the network device based on a received preamble code sequence.

[0070] For example, Figure 3A , assuming that the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1] (in actual cases, the length of the ZC sequence is much longer than this, and this sequence is only for example convenience), the terminal device determines that the first preamble code to be sent to the network device is [1 1 0 1 1 1 1 0 0 1 ], the index corresponding to the first preamble is 61, and the terminal device sends the first preamble to the network device. The network device should receive the first symbol of preamble1 at the first position of the preamble window, and the second symbol of preamble1 at the second position of the preamble window. And so on, receive the entire complete preamble1. However, due to the delay, the preamble is delayed in reaching the network device, and the network device does not receive the symbol at the first position of the preamble window. The network device also does not receive the symbol at the second position of the preamble window. The network device receives the first symbol of preamble1 at the third position of the preamble window. Since the length of the window is fixed and the first two positions of the window do not carry symbols, the final received sequence loses the last two symbols of preamble1, and the incomplete sequence received by the network device is [1 1 0 1 1 1 1 0]. The network device autocorrelates the incomplete sequence with the preset ZC sequence (root sequence), that is, autocorrelates [1 1 0 1 1 1 1 0] and [1 0 0 1 1 1 0 1 1 1], and recognizes the incomplete sequence as preamble 2 [0 1 1 1 0 1 1 1 1 0], the network device believes that the preamble it received is preamble 2. The index of preamble 2 is 59 (the second index), and the second index is carried in the response message and sent to the terminal device. When the reason for the random access failure is the mismatch of the preamble, the terminal device determines that the first index difference is 61-59=2.

[0071] Optionally, the index of the preamble is related to the cyclic shift amount of the preamble, and the larger the cyclic shift amount of the preamble, the larger the index of the preamble. For example, the index of the preamble with a cyclic shift amount of 4 is smaller than the index of the preamble with a cyclic shift amount of 4.

[0072] 202. The terminal device sends a first preamble code to the network device based on the first index difference.

[0073] Optionally, the terminal device sends a first preamble code to the network device in advance based on the first index difference.

[0074] In a possible embodiment, the terminal device sends a first preamble code to the network device based on the first index difference, including: the terminal device determines an advance time amount based on the first index difference; the terminal device sends the first preamble code in advance based on the advance time amount.

[0075] The advance time is used to indicate that the first preamble code is sent in advance, and the advance time is used to offset the delay between the terminal device and the network device.

[0076] For example, Figure 3B As shown, the terminal device starts to send the first preamble code to the network device at time A. Assume that the network device should also start to receive the first symbol of the first preamble code at time A. However, due to the delay, the network device receives the first preamble code at time B, and the network device starts to receive from the third symbol. Now, in order to avoid the network device losing the first two symbols and misidentifying the preamble code, the terminal device sends the first preamble code in advance (the advance time is: advance time amount), that is, it is sent before time A, so that the network device just receives the first preamble code at time A, so that the network device will not lose the symbol of the first preamble code and accurately identify the first preamble code.

[0077] In a possible embodiment, the terminal device determines the advance time based on the first index difference, including: when the terminal device fails in random access for N consecutive times due to preamble code mismatch, the terminal device determines the advance time based on the first index difference, where N is a positive integer greater than 0.

[0078] Optionally, N is a pre-set value. Assuming N is 3, when the terminal device fails in random access for three consecutive times due to preamble code mismatch, the terminal device determines the advance time based on the first index difference.

[0079] In a possible embodiment, when the reason for N consecutive random access failures of the terminal device is preamble code mismatch, the terminal device determines the advance time amount based on the first index difference, including: when the reason for N consecutive random access failures of the terminal device is preamble code mismatch, and the index differences under the N consecutive random access failures are all within a preset range, the terminal device determines the advance time amount based on the first index difference.

[0080] Exemplarily, assuming that N is 3, the preset range can be 2, that is, when the reason for three consecutive random access failures is preamble code mismatch, and the index difference under three consecutive random access failures is less than or equal to 2, the advance time is determined based on the first index difference.

[0081] Optionally, when the reason for N consecutive random access failures of the terminal device is preamble code mismatch, and the index difference values ​​under the N consecutive random access failures are all within a preset range, and the index difference values ​​under the N consecutive random access failures are the same, the advance time amount is determined based on the first index difference.

[0082] Exemplarily, assuming that N is 3, the preset range may be 2, that is, when the cause of three consecutive random access failures is preamble mismatch, and the index difference under the three consecutive random access failures is a fixed 2, the advance time amount is determined based on the first index difference. Alternatively, when the index difference under the three consecutive random access failures is a fixed 1, the advance time amount is determined based on the first index difference.

[0083] Here is how to determine the amount of lead time: In a possible embodiment, the terminal device determines the advance time based on the first index difference, including: the terminal device determines the advance time based on the first index difference, the sequence length of the first preamble code, the unit cyclic shift amount of the first preamble code, and the subcarrier spacing.

[0084] The sequence length of the first preamble is the same as the length of the ZC sequence, or in other words, the length of the first preamble is the same as the length of the root sequence. Assuming that the length of the ZC sequence is 139, cyclic shifting the ZC (root sequence) will not change the length of the sequence, so the length of the first preamble obtained after cyclic shifting the ZC sequence is the same as the length of the ZC sequence. The unit cyclic shift amount of the first preamble represents the step size of each cyclic shift of the ZC sequence. Assuming that the ZC sequence is [10 0 1 1 1 0], the sequence obtained after cyclic shifting the ZC sequence once is [0 1 1 1 0 1 0 ], the unit cyclic shift amount is 2. That is to say, the ZC sequence is cyclically shifted by two symbols each time. If a cyclic shift is performed once, the cyclic shift value is 1, and the cyclic shift is two symbols; if a cyclic shift is performed twice, the cyclic shift value is 2, and the cyclic shift is four symbols.

[0085] In a possible embodiment, the advance time amount satisfies the following formula:

[0086] in, is the sequence length of the first preamble code, that is, the length of the ZC sequence. is the subcarrier spacing, is the unit cyclic shift of the first preamble code, is the first index difference, and T is the advance time.

[0087] In a possible embodiment, after the terminal device sends the first preamble code in advance based on the advance time amount, the method further includes: if the random access fails, the terminal device adds the cell corresponding to the network device to a blacklist.

[0088] Optionally, after the terminal device sends the first preamble in advance, random access still fails. At this time, the random access failure may not be caused by the preamble mismatch caused by the delay, or the reason for the random access failure may not be the preamble mismatch. At this time, the terminal device adds the cell corresponding to the network device to the blacklist and no longer accesses the cell.

[0089] Optionally, after the terminal device adds the cell corresponding to the network device to the blacklist, it triggers a radio link failure (RLF) to try to access other cells.

[0090] Optionally, if the random access fails and the number of random access failures is greater than a preset threshold, the cell corresponding to the network device is added to a blacklist.

[0091] The number of random access failures may be the total number of failures in attempting to access the cell corresponding to the network device, or may be the number of random access failures after adopting the scheme of sending the first preamble code in advance.

[0092] Exemplarily, after the terminal device sends the first preamble code in advance, if random access still fails, the first preamble code is sent in advance again based on the time advance amount. If it fails again; the first preamble code is sent in advance again based on the time advance amount. If it still fails and the preset threshold is 2, the cell corresponding to the network device is added to the blacklist.

[0093] Combine the following Figure 3C The method of sending the first preamble code in advance is further introduced. The terminal device initiates random access; after the random access fails, the terminal device determines whether the reason for the random access failure is the preamble code mismatch; if the failure reason is the preamble code mismatch, it determines whether the index difference is 1 or 2; if the index difference is a fixed 1 or 2, it determines the number of consecutive random access failures; if the number of failures does not reach 3, the first preamble code continues to be sent according to the previous sending method; if it reaches 3 times, the advance time is calculated, and based on the advance time, the first preamble code is sent to the network device in advance. If the method of sending the first preamble code in advance also fails, the cell is added to the blacklist and the RLF process is triggered.

[0094] The above scheme sends the first preamble code in advance to offset the time delay between the terminal device and the network device, so that the sequence received by the network device is complete, avoiding the network device mistaking the received sequence for other preamble codes, thereby avoiding random access failure caused by preamble code mismatch. The method of sending the first preamble code in advance can improve the probability of successful random access. In addition to the method of sending the first preamble code in advance, the present application also provides another scheme to improve the probability of successful random access. This other scheme can send a new preamble code when the cause of random access failure is preamble code mismatch, so that the network device can mistake the new preamble code for the first preamble code, thereby achieving preamble code matching. Specifically: In a possible embodiment, when the reason for the failure of random access is preamble code mismatch, the terminal device determines a second preamble code, where the second preamble code is determined based on the first index difference; the terminal device sends the second preamble code to the network device.

[0095] Optionally, the terminal device always considers that the index of the preamble code sent by itself is the first index, that is, although the terminal device sends the second preamble code to the network device, the terminal device still considers that the index of the preamble code sent by itself is the first index.

[0096] The present application provides a communication device that can be used to implement the functions of the above terminal device. The communication device includes a module or unit corresponding to the method / operation / step / action performed by the terminal device in the above method embodiment. The unit can be a hardware circuit, or software, or a combination of a hardware circuit and software. Figure 4 As shown, Figure 4 The structure diagram of a communication device 400 according to an embodiment of the present application is shown. The communication device 400 may include a processing unit 401 and an interface unit 402. The processing unit 401 is used to process signaling and / or data, which may be data received by the interface unit 402, and the processed signaling and / or data may also be sent by the interface unit 402; wherein: The processing unit 401 is configured to determine a first index difference when the reason for the random access failure is that the preamble code does not match, where the first index difference is a difference between a first index and a second index, the first index is an index of the first preamble code sent, and the second index is a preamble code index in the received response message; The interface unit 402 is configured to send a first preamble code to the network device based on the first index difference.

[0097] In a possible embodiment, the processing unit 401 is further configured to determine an advance time amount based on the first index difference; and send the first preamble code in advance based on the advance time amount.

[0098] In a possible embodiment, the processing unit 401 is further configured to determine the advance time amount based on the first index difference when the cause of N consecutive random access failures is preamble mismatch, where N is a positive integer greater than 0.

[0099] In a possible embodiment, the processing unit 401 is further configured to determine the advance time amount based on the first index difference when the cause of N consecutive random access failures is preamble code mismatch and the index differences under the N consecutive random access failures are all within a preset range.

[0100] In a possible embodiment, the processing unit 401 is further configured to determine the advance time amount based on the first index difference, the sequence length of the first preamble code, the unit cyclic shift amount of the first preamble code, and the subcarrier spacing.

[0101] In a possible embodiment, the processing unit 401 is further configured to add a cell corresponding to the network device to a blacklist if the random access fails.

[0102] In a possible embodiment, the processing unit 401 is further configured to add a cell corresponding to the network device to a blacklist if the random access fails and the number of random access failures is greater than a preset threshold.

[0103] like Figure 5 The present invention provides a communication device 500, which is used to implement the functions of the above-mentioned terminal device. The device may be a communication device or a device used in a communication device. The communication device may be a terminal device. The device used in the communication device may be a chip system or a chip in the communication device. The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0104] The communication device 500 includes at least one processor 510, which is used to implement the processing function of the device (such as a terminal device) in the method provided in the embodiment of the present application.

[0105] Optionally, the communication device 500 may further include a communication interface 520 for implementing the transceiver operation of the device (e.g., terminal device) in the method provided in the embodiment of the present application. In the embodiment of the present application, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface, which is used to communicate with other devices through a transmission medium. For example, the communication interface 520 is used for the device in the communication device 500 to communicate with other devices. The processor 510 uses the communication interface 520 to send and receive data, and is used to implement the method described in the above method embodiment. Figure 5 As shown, the communication interface 520 may be located inside the communication device 500 or outside the communication device 500, which is not limited in the embodiment of the present application.

[0106] Optionally, the communication device 500 may also include at least one memory 530 for storing program instructions and / or data. The memory 530 is coupled to the processor 510. The coupling in the embodiment of the present application is an indirect coupling or communication connection between devices, units or modules, which may be electrical, mechanical or other forms, and is used for information exchange between devices, units or modules. The processor 510 may operate in conjunction with the memory 530. The processor 510 may execute program instructions stored in the memory 530. At least one of the at least one memory may be included in the processor 510. Alternatively, the at least one memory may be located within the communication device 500 and outside the processor 510. Alternatively, the at least one memory may be located outside the communication device 500, which is not limited in the embodiment of the present application.

[0107] The specific connection medium between the communication interface 520, the processor 510 and the memory 530 is not limited in the embodiment of the present application. Figure 5 In the embodiment, the memory 530, the processor 510 and the communication interface 520 are connected via a bus. Figure 5The connections between the other components are shown in bold lines, which are only for illustration and are not intended to be limiting. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0108] When the communication device 500 is specifically a device for a device (such as a sending device or a receiving device), for example, when the communication device 500 is specifically a chip or a chip system, the communication interface 520 may output or receive a baseband signal. When the communication device 500 is specifically a device (such as a sending device or a receiving device), the communication interface 520 may output or receive a radio frequency signal. In an embodiment of the present application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in conjunction with the embodiments of the present application may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0109] It should be noted that the communication interface 520 may be used to execute the function of the interface unit 402, and the processor 510 may be used to execute the function of the processing unit 401, which will not be described in detail herein.

[0110] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0111] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable ROM (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal device. Of course, the processor and the storage medium can also be present in a sending device or a receiving device as discrete components.

[0112] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instruction is loaded and executed on a computer, the process or function described in the embodiment of the present application is executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program or instruction may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a tape; it may also be an optical medium, such as a DVD; it may also be a semiconductor medium, such as a solid state disk (SSD).

[0113] In the various embodiments of the present application, unless otherwise specified or provided for in any logical conflict, the terms and / or descriptions between the different embodiments are consistent and may be referenced to each other, and the technical features in the different embodiments may be combined to form new embodiments according to their inherent logical relationships.

[0114] It is understood that the various numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic.

[0115] An embodiment of the present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed, the method executed by the terminal device or the network device in the above method embodiment is implemented.

[0116] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed, the method executed by the sending device or the receiving device in the above method embodiment is implemented.

[0117] The embodiment of the present application also provides a communication system, which includes a sending device or a receiving device. The sending device is used to execute the method executed by the sending device in the above method embodiment. The receiving device is used to execute the method executed by the receiving device in the above method embodiment.

[0118] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0119] The descriptions of the various embodiments provided in this application can refer to each other, and the descriptions of the various embodiments have their own emphasis. For parts that are not described in detail in a certain embodiment, refer to the relevant descriptions of other embodiments. For the convenience and simplicity of description, for example, the functions of the various devices and equipment provided in the embodiments of this application and the steps of execution can refer to the relevant descriptions of the method embodiments of this application, and the various method embodiments and the various device embodiments can also refer to, combine or quote each other.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A random access method, characterized in that: The method comprises: When the reason for the random access failure is that the preamble code does not match, determine a first index difference value, where the first index difference value is a difference between a first index and a second index, where the first index is an index of a first preamble code sent, and the second index is a preamble code index in a received response message; Based on the first index difference, a first preamble code is sent to the network device.

2. The method according to claim 1, characterized in that The sending a first preamble code to a network device based on the first index difference includes: determining an advance time amount based on the first index difference; The first preamble is sent in advance based on the advance time amount.

3. The method according to claim 2, characterized in that The determining the advance time amount based on the first index difference includes: In a case where the cause of N consecutive random access failures is preamble code mismatch, the advance time amount is determined based on the first index difference, and N is a positive integer greater than 0.

4. The method according to claim 3, characterized in that The determining, when the reason for the N consecutive random access failures is that the preamble code does not match, based on the first index difference, the advance time amount includes: When the cause of N consecutive random access failures is preamble code mismatch, and the index difference values ​​under the N consecutive random access failures are all within a preset range, the advance time amount is determined based on the first index difference value.

5. The method according to any one of claims 2 to 4, characterized in that: The determining the advance time amount based on the first index difference includes: An advance time amount is determined based on the first index difference, the sequence length of the first preamble code, the unit cyclic shift amount of the first preamble code, and the subcarrier spacing.

6. The method according to claim 5, characterized in that After sending the first preamble code in advance based on the advance time amount, the method further includes: If the random access fails, the cell corresponding to the network device is added to the blacklist.

7. The method according to claim 6, characterized in that If the random access fails, the cell corresponding to the network device is added to a blacklist, and the method further includes: If the random access fails, and the number of random access failures is greater than a preset threshold, the cell corresponding to the network device is added to a blacklist.

8. A communication device, characterized in that: The method comprises a unit for executing the method as claimed in any one of claims 1 to 7.

9. A chip system, characterized in that: The method comprises a processor and a memory, wherein the processor and the memory are coupled, and the processor is used to implement the method according to any one of claims 1 to 7.

10. A chip, characterized in that: It comprises a processor and an interface, wherein the processor and the interface are coupled; the interface is used to receive or output signals, and the processor is used to execute code instructions so that the method described in any one of claims 1 to 7 is executed.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called, the computer executes the method described in any one of claims 1 to 7.

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