Random access method and communication device

Abstract

The present application discloses a random access method and a communication device. The method includes: when the reason for the random access failure is that the preamble does not match, determining a first index difference, where the first index difference is the difference between a first index and a second index, the first index is the index of the first preamble sent, and the second index is the preamble index in the received response message; and sending the first preamble to a network device based on the first index difference. By adopting this method, the success probability of random access can be improved.

Description

Technical Field

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

[0002] When 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 the msg1, the network device sends a response message msg2 (msg2 contains the index of the preamble, preambleindex) to the terminal device in response to the msg1. After receiving the msg2 containing the index of the preamble it sent, the terminal device can successfully perform subsequent operations of random access.

[0003] However, for long-distance access (the physical distance between the network device and the terminal device is relatively far), the following situation will occur: The terminal device sends a first message msg1 containing a 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 misidentifies the preamble as another preamble. The preamble index in the msg2 sent by the network device to the terminal device is different from the index corresponding to the preamble in the msg1. The terminal device then believes that it has not received the msg2 corresponding to the msg1 it sent, which will result in random access failure.

[0004] For example, assume that 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 recognized by the network device becomes preambleB, and the preamble index corresponding to the preambleB is 59. Then the preamble index contained in the 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, rather than 61, and the terminal device believes that it has not received the corresponding msg2. This leads to random access failure. Summary of the Invention

[0005] This 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 random access failure is preamble mismatch, determining a first index difference, where the first index difference is the difference between a first index and a second index, the first index being the index of the first preamble sent, and the second index being the preamble index in the received response message; based on the first index difference, sending the first preamble to a network device.

[0007] By the above method, the first preamble is sent 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 misidentifying the received sequence as other preambles, and thus avoiding random access failure caused by preamble mismatch. Using the method of sending the first preamble in advance can increase the probability of successful random access.

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

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

[0010] In a possible embodiment, when the reason for consecutive N random access failures is preamble mismatch, determining the advance time amount based on the first index difference includes: when the reason for consecutive N random access failures is preamble mismatch and the index differences in consecutive N random access failures are all within a preset range, determining the advance time amount based on the first index difference.

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

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

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

[0014] In a second aspect, the present application provides a communication device. For example, the communication device can be a module of a terminal device, such as a processor, a chip, or a chip system, and can 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 of the methods in the first aspect and its possible implementations.

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

[0016] In a fourth aspect, the present application provides a chip, which includes a processor and an interface. The processor is coupled to the interface. 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, in which computer-executable instructions are stored. When the computer-executable instructions are called, the method described in the first aspect is caused to be executed.

[0018] In a sixth aspect, the present application provides a computer program product, which includes computer program code. When the computer program code is run, the method described in the first aspect is caused to be 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 above. Description of the Drawings

[0020] Figure 1A It is a schematic diagram of a communication system provided by an embodiment of the present application;

[0021] Figure 1B It is another schematic diagram of a communication system provided by an embodiment of the present application;

[0022] Figure 1C It is a schematic diagram of the principle of misidentifying a preamble provided by an embodiment of the present application;

[0023] Figure 2 It is a schematic flowchart of a random access method provided by an embodiment of the present application;

[0024] Figure 3A It is a schematic diagram of a random access failure provided by an embodiment of the present application;

[0025] Figure 3B It is a schematic diagram of another random access method provided by an embodiment of the present application;

[0026] Figure 3C Schematic diagram of another random access method provided by an embodiment of the present application;

[0027] Figure 4 Schematic diagram of a communication device provided by the present application;

[0028] Figure 5 Schematic diagram of another communication device provided by the present application. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent 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 may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality of" means two or more than two.

[0030] 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 "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. 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 optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0031] Referring to "embodiment" in the present application means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.

[0032] To better understand the present application, the random access process involved in the present application will be introduced first. The random access process is divided into two types: contention-based random access and non-contention-based random access.

[0033] The contention-based random access mainly includes the following steps:

[0034] First, the terminal device randomly selects a preamble from the contention-based preamble pool shared with other terminal devices in the cell.

[0035] The terminal device sends Msg1 to the network device: The Msg1 contains the preamble randomly selected by the terminal device from the preamble pool.

[0036] 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 (Msg2), and the Msg2 contains the preamble index.

[0037] 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 sends a high-layer signaling message using the allocated resources, that is, it sends Msg3 according to the time-frequency resource location configured by Msg2.

[0038] The network device sends Msg4 to the terminal device: The network device sends a conflict resolution response. The terminal device determines whether the contention is successful.

[0039] The contention-free random access mainly includes the following steps:

[0040] First, the network device allocates a specific preamble for the terminal device according to the requirements. The network device can inform the terminal device of the specific preamble through Msg0.

[0041] The terminal device sends Msg1 to the network device: The Msg1 contains the specific preamble allocated by the network device.

[0042] 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.

[0043] Whether it is contention-based random access or contention-free random access, the preamble is crucial. According to the NR protocol or LTE protocol regulations, the preamble is constructed from the ZC sequence after cyclic shift:

[0044]

[0045]

[0046] Among them, represents the length of The ZC sequence. u is the physical root sequence number, and this physical root sequence 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.

[0047] Among them, represents the preamble, is the v-th cyclic shift amount, and this satisfies the following formula:

[0048]

[0049] Among them, is the unit cyclic shift amount and is configured by the upper layer.

[0050] It can be seen from the above three formulas that different cyclic shifts of the ZC sequence will result in multiple preambles. There are 64 preambles (obtained by different cyclic shifts of multiple root sequences) in the preamble pool of the cell for the terminal device to select to initiate random access (as introduced in the above contention-based random access). Among them, the determination method of these 64 preambles is: starting from the initial root index configured by the upper layer, for the ZC sequence corresponding to each 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 this ZC sequence is recorded as 1 preamble, and so on until 64 preambles are determined.

[0051] Exemplarily, assume the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1] (in actual situations, the length of the ZC sequence is much more than this, and this sequence is only for convenient example). is 2, that is, the unit cyclic shift amount is 2, and when this ZC sequence is cyclically shifted, it is in units of two bits. For example, after a cyclic shift of this ZC sequence, [0 1 1 1 0 1 1 1 1 0] is obtained ( 1 0 0 1 1 1 0 1 1 1] —> [0 1 1 1 0 1 1 1 1 0 ), and [0 1 1 1 0 1 1 1 1 0] is a obtained preamble. After two cyclic shifts of this ZC sequence, [1 1 0 1 1 1 1 0 0 1] is obtained ( 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 obtained preamble. And so on.

[0052] From the perspective of the Physical Random Access Channel (PRACH), it determines the coverage distance of the PRACH. When the terminal device sends a preamble from a location outside the PRACH coverage range, the network device may mistake this preamble for another preamble.

[0053] Exemplarily, assume that the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1], and the preamble1 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 ).

[0054] When the terminal device sends preamble1 at a location within the PRACH coverage range, it can be regarded that there is no time delay between the network device and the terminal device. At this time, the network device receives this preamble1 in the corresponding window, the network device receives the complete preamble1, and carries the index corresponding to this preamble1 in Msg2 and feeds it back to the terminal device for the terminal device to perform subsequent random access operations.

[0055] However, when the terminal device sends preamble1 at a location outside the PRACH coverage range, there is a time delay between the network device and the terminal device. As Figure 1C shown, the network device should have received 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, to receive the entire complete preamble1. However, due to the time delay, the preamble arrives at the network device late. The network device does not receive a symbol at the first position of the preamble window, and the network device also does not receive a symbol at the second position of the preamble window. The network device receives the first symbol of preamble1 only 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 finally received sequence misses the last two symbols of preamble1, and the incomplete sequence received by the network device is [1 1 0 1 1 1 1 0].

[0056] The network device performs autocorrelation on the incomplete sequence and a preset ZC sequence (root sequence), that is, performs autocorrelation on [1 1 01 1 1 1 0] and [1 0 0 1 1 1 0 1 1 1]. The network device recognizes the incomplete sequence as preamble2[0 1 1 1 0 1 1 1 1 0 . preamble2[0 1 1 1 0 1 1 1 1 0 is clearly different from preamble1[1 1 0 1 1 1 1 0 0 1 sent by the terminal device. preamble2 has fewer cyclic shifts than preamble1, and the index corresponding to preamble2 is less 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. When the terminal device finds that the index in the received Msg2 is not the index corresponding to the preamble1 it sent, the terminal device re-sends Msg1 carrying preamble1 to the network device. Similarly, due to the time delay problem, the network device will still misidentify preamble1 as preamble2. 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, the random access fails.

[0057] 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.

[0058] To solve the above problems and improve the success probability of random access, this application provides a random access method. By sending a first preamble to the network device through a first index difference, the network device can start receiving preamble1 from the first symbol, realizing the alignment of the preamble sent by the terminal device and the preamble considered by the network device, thus avoiding the problem of random access failure caused by the network device misidentifying the preamble, and further improving the success probability of random access.

[0059] To better understand the embodiments of this application, the communication system involved in this application will be introduced first.

[0060] First, the network device involved in this application refers to a device that can communicate with a terminal device.

[0061] The terminal device involved in this application: is an entity on the user side that is used to receive signals, or transmit signals, or receive and transmit signals. The terminal device is used to provide one or more of voice services and data connectivity services to users. The terminal device can be a device that includes a wireless transceiver function and can cooperate with a network device to provide communication services to users. Specifically, the terminal device can refer to: user equipment, access terminal, user unit, user station, mobile station, mobile terminal, remote station, remote terminal, mobile device, terminal, wireless communication device, user agent, user device, or roadside unit (RSU). The user equipment can 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 devices connected to a wireless modem, a vehicle-mounted device, a wearable device (which can also be called a wearable intelligent 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 a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. The user equipment can also be a terminal in a 5G system or a terminal in a next-generation communication system, and the embodiments of this application do not limit this.

[0062] Embodiments of this application do not limit the form of the user equipment. The device for implementing the functions of the user equipment may be the user equipment; or it may be a device capable of supporting the user equipment to implement the functions, such as a chip system. This device may be installed in the user equipment or used in combination with the user equipment. In the embodiments of this application, the chip system may be composed of chips or may include chips and other discrete devices.

[0063] Network device: An entity on the network side that is used to send signals, or receive signals, or send and receive signals. The network device may be a device deployed in a radio access network (RAN) to provide wireless communication functions for user equipment.

[0064] In a possible scenario, the network device can be a device with base station functions, such as an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting 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-terrestrial network device, that is, a device that can be deployed on a high-altitude platform or a satellite, etc. The network device can be a transmission reception point (TRP), a base station, or various forms of control nodes. For example, a network controller, a radio controller, etc. Specifically, the network device can be various forms of macro base stations, micro base stations (also known as small stations) in a heterogeneous network (HetNet) scenario, relay stations, access points (APs), radio network controllers (RNCs), Node Bs (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home base stations (e.g., home evolved nodeB, or home node B, HNBs), baseband units (BBUs) and radio remote units (RRUs) in a distributed base station scenario, transmitting and receiving points (TRPs), transmitting points (TPs), mobile switching centers, etc., or can also be an antenna panel of a base station. The control node can be connected to multiple base stations and configure resources for multiple terminals covered by the multiple base stations. In systems adopting different radio access technologies, the names of devices with base station functions may be different. For example, it can be a gNB in 5G, or a network-side device in a network after 5G or a network device in a future evolved public land mobile network (PLMN), or a device that undertakes base station functions in device-to-device (D2D) communication, machine-to-machine (M2M) communication, vehicle-to-everything (V2X) communication, etc. The present application does not limit the specific name of the network device.The network device can also be a baseband unit pool (BBU pool) and RRU under an open radio access network (openRAN, O-RAN or ORAN), a cloud radio access network (CRAN), etc.

[0065] In another possible scenario, multiple network devices cooperate to assist a user equipment in achieving wireless access, and different network devices respectively implement some functions of a base station. For example, the network device can include a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately provided, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as included in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It can be understood that the network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be classified as a network device in the radio access network RAN, or the CU can be classified as a network device in the core network CN, which is not limited herein.

[0066] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, the CU can also be called an O-CU (open CU), the DU can also be called an O-DU, the CU-CP can also be called an O-CU-CP, the CU-UP can also be called an O-CU-UP, and the RU can also be called an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU, and RU are used as examples in this application. Any one of the CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0067] In the embodiments of this application, the form of the network device is not limited. The device for implementing the functions of the network device can be the network device; it can also be a device capable of supporting the network device to implement such functions, such as a chip system. The device can be installed in the network device or used in matching with the network device.

[0068] Exemplarily, as Figure 1A shown, Figure 1A is a schematic diagram of an application scenario of an embodiment of the present application. As Figure 1A shown, the application scenario may include a sending terminal device and a network device. Among them, the network device may be any of the above forms of network devices. Correspondingly, the terminal device may be any of the above forms of terminal devices.

[0069] In a possible embodiment, the terminal device first sends a preamble to the network device for random access. When 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 in 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 increased.

[0070] Exemplarily, Figure 1B is a schematic diagram of another application scenario provided by an embodiment of the present application. As Figure 1B shown, this scenario is illustrated by taking one terminal device and two network devices as an example. Among them, the relationship between the terminal device and the two network devices is as follows: Cell 2 (Cell 2 corresponding to Network Device 2) is the current serving cell of the terminal device, and Cell 1 (Cell 1 corresponding to Network Device 1) is a cell with better signal quality discovered by the terminal device. The terminal device selects Cell 1 as the new serving cell.

[0071] As Figure 1B shown, the terminal device is at the coverage edge of Cell 2 (the current serving cell) and is gradually leaving Cell 2. Due to some network deployment reasons, for the cell with better signal quality discovered by the terminal device, the terminal device selects to switch from Cell 2 to Cell 1. The reasons for this network deployment are, for example: the transmission power of Cell 1 is higher than that of Cell 2 and other nearby cells, or the antenna deployment height of Cell 2 and other nearby cells is relatively low, resulting in the signal being blocked by the surrounding buildings of the terminal device, while the antenna deployment height of Cell 1 is relatively high, so that the signal of this Cell 1 avoids being blocked by the surrounding buildings of the terminal device.

[0072] However, since the physical distance between Cell 1 and the terminal device is relatively far, when the terminal device sends a preamble to Cell 1 to initiate a random access process, due to the time delay caused by the physical distance, the network device will mistake the received preamble for another preamble, and thus feedback an incorrect preamble index to the terminal device, and further cause the random access to fail due to the reason of preamble mismatch.

[0073] To solve this problem, the present application proposes a random access method. In the embodiment of the present application, the network device may be the Figure 1B Network Device 1 (Cell 1) in this

[0074] In a scenario where the physical distance between the terminal device and the network device is relatively far, in addition to the scenarios described above Figure 1B shown, it is also relatively common in a non-terrestrial network (NTN) scenario.

[0075] As described above, the technical solution of this application can be applied to an NTN system. NTN refers to a network or network segment that uses the radio frequency on a satellite. In an 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 device is called a feeder link. The network device can transmit data to the satellite through the feeder link, and the user equipment can transmit data to the satellite through the service link. Or the technical solution of this application can be applied to a scenario where NTN is integrated with a terrestrial network (TN).

[0076] Next, in combination with the attached Figure 2 The random access method provided by the embodiments of this application will be further introduced. It can be understood that in this application, the terminal device and the receiving device are used as examples of the execution entities of this interaction schematic, but it does not limit the execution entities of the interaction schematic itself. For example, the method executed by the terminal device in this application can also be executed by a module applied to the terminal device (such as a chip, a chip system, or a processor), and can also be implemented by a logical node, a logical module, or software that can implement all or part of the functions of the terminal device. Among them:

[0077] 201. When the reason for the random access failure of the terminal device is that the preambles do not match, determine a first index difference. The first index difference is the difference between a first index and a second index. The first index is the index of the first preamble sent, and the second index is the preamble index in the received response message;

[0078] Among them, the first preamble is the preamble sent by the terminal device to the network device before the random access failure. The response message is the response message received by the terminal device from the network device before the random access failure.

[0079] In a possible embodiment, before the terminal device determines the first index difference when the reason for the random access failure is that the preambles do not match, the method further includes: the terminal device sends a first preamble to the network device; the terminal device receives the response message sent by the network device; the terminal device determines whether the reason for the random access failure is that the preambles do not match based on the first preamble and the response message.

[0080] Among them, the response message is the response message corresponding to the first preamble, the first preamble is carried and sent in Msg1, and the response message includes the index of the preamble. The response message is Msg2.

[0081] Optionally, the terminal device determines whether the reason for the random access failure is preamble mismatch based on the first preamble and the response message, including: when the preamble index in the response message is different from the index of the first preamble, the terminal device determines that the reason for the random access failure is mismatch.

[0082] Optionally, the terminal device sends the preamble to the network device multiple times and receives the response message multiple times.

[0083] Optionally, the second index is the index of the preamble considered by the network device based on the received preamble sequence.

[0084] Exemplarily, for example Figure 3A , assuming that the ZC sequence (root sequence) is [1 0 0 1 1 1 0 1 1 1] (in actual situations, 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 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 have received 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, receiving the entire complete preamble1. However, due to the time delay, the preamble arrives at the network device late. The network device does not receive the symbol at the first position of the preamble window, and 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 finally 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 performs autocorrelation on the incomplete sequence and the preset ZC sequence (root sequence), that is, performs autocorrelation on [1 1 0 1 1 1 1 0] and [1 0 0 1 1 1 0 1 1 1], and the network device identifies the incomplete sequence as preamble2 [0 1 1 1 0 1 1 1 1 0, the network device believes that the preamble it received is preamble2. The index of this preamble2 is 59 (the second index), and this second index is carried in the response message and sent to the terminal device. When the reason for the random access failure of the terminal device is that the preambles do not match, the terminal device determines that the first index difference is 61 - 59 = 2.

[0085] Optionally, the index of the preamble is related to the cyclic shift amount of this preamble. The larger the cyclic shift amount of this preamble, the larger the index of the preamble. For example, the index of the preamble with a cyclic shift amount of 4 is less than the index of the preamble with a cyclic shift amount of 4.

[0086] 202. The terminal device sends a first preamble to the network device based on the first index difference.

[0087] Optionally, the terminal device sends the first preamble to the network device in advance based on the first index difference.

[0088] In a possible embodiment, the terminal device sending the first preamble to the network device based on the first index difference includes: the terminal device determines an advance time amount based on the first index difference; the terminal device sends the first preamble in advance based on the advance time amount.

[0089] Among them, the advance time amount is used to indicate sending the first preamble in advance, and this advance time amount is used to offset the time delay between the terminal device and the network device.

[0090] Exemplarily, for example Figure 3B As shown, the terminal device starts to send this first preamble to the network device at time A. Assume that originally the network device should also start receiving the first symbol of this first preamble at time A. However, due to the time delay, the network device receives this first preamble at time B, and at this time the network device starts receiving from the third symbol. Now, in order to prevent the network device from missing the previous two symbols and misidentifying the preamble, the terminal device sends the first preamble in advance (the advance time is: the advance time amount), that is, sends it before time A, so that the network device just receives this first preamble at time A, so that the network device will not miss the symbols of the first preamble and accurately identify this first preamble.

[0091] In a possible embodiment, the terminal device determining the advance time amount based on the first index difference includes: when the reason for the continuous N random access failures of the terminal device is that the preambles do not match, the terminal device determines the advance time amount based on the first index difference, where N is a positive integer greater than 0.

[0092] Optionally, N is a preset value. Assuming N is 3, when the reason for the terminal device's consecutive three random access failures is preamble mismatch, the terminal device determines the advance time amount based on the first index difference.

[0093] In a possible embodiment, when the reason for the terminal device's consecutive N random access failures is preamble mismatch, the terminal device determines the advance time amount based on the first index difference, including: when the reason for the terminal device's consecutive N random access failures is preamble mismatch and the index differences in the consecutive N random access failures are all within a preset range, the terminal device determines the advance time amount based on the first index difference.

[0094] Exemplarily, assuming N is 3, the preset range can be 2, that is, when the reason for the consecutive 3 random access failures is preamble mismatch and the index differences in the consecutive 3 random access failures are all less than or equal to 2, the terminal device determines the advance time amount based on the first index difference.

[0095] Optionally, when the reason for the terminal device's consecutive N random access failures is preamble mismatch, the index differences in the consecutive N random access failures are all within a preset range, and the index differences in the consecutive N random access failures are the same, the terminal device determines the advance time amount based on the first index difference.

[0096] Exemplarily, assuming N is 3, the preset range can be 2, that is, when the reason for the consecutive 3 random access failures is preamble mismatch and the index differences in the consecutive 3 random access failures are all fixed at 2, the terminal device determines the advance time amount based on the first index difference. Or, when the index differences in the consecutive 3 random access failures are all fixed at 1, the terminal device determines the advance time amount based on the first index difference.

[0097] The following introduces how to determine the advance time amount:

[0098] In a possible embodiment, the terminal device determines the advance time amount based on the first index difference, including: the terminal device determines the advance time amount based on the first index difference, the sequence length of the first preamble, the unit cyclic shift amount of the first preamble, and the subcarrier spacing.

[0099] Among them, the sequence length of the first preamble is the same as the length of the ZC sequence, or rather, the length of the first preamble is the same as the length of the root sequence. Assuming the length of the ZC sequence is 139, performing a cyclic shift on this ZC (root sequence) will not change the sequence length. Therefore, the length of the first preamble obtained by performing a cyclic shift on 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 the ZC sequence is [10 0 1 1 1 0], the sequence obtained after performing a cyclic shift on this ZC sequence is [0 1 1 1 0 1 0 , and the unit cyclic shift amount is 2. That is to say, each time the ZC sequence is cyclically shifted according to two symbols. If a cyclic shift is performed once, the cyclic shift value is 1, and two symbols are cyclically shifted; if two cyclic shifts are performed, the cyclic shift value is 2, and 4 symbols are cyclically shifted.

[0100] In a possible embodiment, the advance time amount satisfies the following formula:

[0101]

[0102] Among them, is the sequence length of the first preamble, that is, the length of the ZC sequence. is the subcarrier spacing, is the unit cyclic shift amount of the first preamble, is the first index difference, and T is the advance time amount.

[0103] In a possible embodiment, after the terminal device sends the first preamble 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 the blacklist.

[0104] Optionally, after the terminal device sends the first preamble in advance and still fails in random access, it may not be due to the preamble mismatch caused by the time delay at this time, 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 this cell.

[0105] Optionally, after the terminal device adds the cell corresponding to the network device to the blacklist, it triggers a Radio Link Failure (RLF) attempt to access other cells.

[0106] 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 the blacklist.

[0107] Among them, the number of random access failures can be the total number of failures in attempting to access the cell corresponding to the network device, or can be the number of random access failures after adopting the scheme of sending the first preamble in advance.

[0108] Exemplarily, after the terminal device sends the first preamble in advance and still fails in random access, the first preamble is sent in advance again based on the timing advance amount. If it fails again, the first preamble is sent in advance again based on the timing advance amount. If it still fails and the preset threshold is 2, the cell corresponding to the network device is added to the blacklist.

[0109] The following Figure 3C will further introduce the method of sending the first preamble in advance. The terminal device initiates a random access. After the random access fails, the terminal device determines whether the reason for the random access failure is that the preambles do not match. If the failure reason is that the preambles do not match, 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 is sent according to the previous sending method. If it reaches 3 times, the timing advance amount is calculated, and based on this timing advance amount, the first preamble is sent to the network device in advance. If the method of sending the first preamble in advance also fails, the cell is added to the blacklist, triggering the RLF process.

[0110] The above scheme offsets the time delay between the terminal device and the network device by sending the first preamble in advance, so that the sequence received by the network device is complete, avoiding the network device misidentifying the received sequence as other preambles, thereby avoiding random access failures caused by the reason of preamble mismatch. Adopting the method of sending the first preamble in advance can increase the probability of successful random access. In addition to the method of sending the first preamble in advance, the present application also provides another scheme to increase the probability of successful random access. This other scheme can send a new preamble when the reason for the random access failure is that the preambles do not match, so that the network device can misidentify the new preamble as the first preamble, thereby achieving preamble matching. Specifically:

[0111] In a possible embodiment, when the reason for the random access failure is that the preambles do not match, the terminal device determines a second preamble, and the second preamble is determined based on a first index difference; the terminal device sends the second preamble to the network device.

[0112] Optionally, the terminal device always considers the index of the preamble it sends as the first index. That is to say, although the terminal device sends the second preamble to the network device, the terminal device still considers the index of the preamble it sends as the first index.

[0113] The present application provides a communication device, which can be used to implement the functions of the above terminal device. The communication device includes modules or units corresponding one by one to the methods / operations / steps / actions executed by the terminal device in the above method embodiments. The unit can be a hardware circuit, software, or a combination of hardware circuit and software. Please refer to Figure 4 as shown in Figure 4 FIG. 4 shows a schematic structural diagram of a communication device 400 according to an embodiment of the present application. 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. The signaling and / or data 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:

[0114] The processing unit 401 is configured to determine a first index difference when the reason for the random access failure is that the preamble does not match. The first index difference is the difference between a first index and a second index. The first index is the index of the first preamble sent, and the second index is the preamble index in the received response message.

[0115] The interface unit 402 is configured to send a first preamble to the network device based on the first index difference.

[0116] 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 in advance based on the advance time amount.

[0117] In a possible embodiment, the processing unit 401 is further configured to determine an advance time amount based on the first index difference when the reason for N consecutive random access failures is that the preamble does not match, where N is a positive integer greater than 0.

[0118] In a possible embodiment, the processing unit 401 is further configured to determine an advance time amount based on the first index difference when the reason for N consecutive random access failures is that the preamble does not match and the index differences in the N consecutive random access failures are all within a preset range.

[0119] In a possible embodiment, the processing unit 401 is further configured to determine an advance time amount based on the first index difference, the sequence length of the first preamble, the unit cyclic shift amount of the first preamble, and the subcarrier spacing.

[0120] In a possible embodiment, the processing unit 401 is further configured to add the cell corresponding to the network device to the blacklist if the random access fails.

[0121] In a possible embodiment, the processing unit 401 is further configured to add the cell corresponding to the network device to the blacklist if the random access fails and the number of random access failures is greater than a preset threshold.

[0122] As Figure 5 shown in the figure is a communication device 500 provided by an embodiment of the present application, which is used to implement the functions of the above terminal device. The device may be a communication device or a device in a communication device. The communication device may be a terminal device. The device in the communication device may be a chip system or a chip in the communication device. Among them, the chip system may be composed of chips or may include chips and other discrete devices.

[0123] 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 by the embodiment of the present application.

[0124] Optionally, the communication device 500 may further include a communication interface 520, which is used to implement the transceiver operation of the device (such as a terminal device) in the method provided by the embodiment of the present application. In the embodiment of the present application, the communication interface may be a transceiver, a circuit, a bus, a module or other types of communication interfaces, and is used to communicate with other devices through a transmission medium. For example, the communication interface 520 in the communication device 500 can 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. As Figure 5 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.

[0125] Optionally, the communication device 500 may further include at least one memory 530, which is used to store 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, and may be electrical, mechanical or other forms, and is used for information interaction between devices, units or modules. The processor 510 may cooperate with the memory 530. The processor 510 may execute the program instructions stored in the memory 530. At least one of the at least one memories may be included in the processor 510. Or, the at least one memory may be located inside the communication device 500 and outside the processor 510. Or, the at least one memory may be located outside the communication device 500, which is not limited in the embodiment of the present application.

[0126] In the embodiment of the present application, the specific connection medium between the communication interface 520, the processor 510 and the memory 530 is not limited. The embodiment of the present application is in Figure 5In the Zhongyi, the memory 530, the processor 510, and the communication interface 520 are connected through a bus, and the bus is shown in Figure 5 thick lines in the Zhongyi. The connection methods between other components are only for illustrative purposes and are not limiting. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of convenience of representation, Figure 5 only one thick line is used to represent it in the Zhongyi, but it does not mean that there is only one bus or one type of bus.

[0127] When the communication device 500 is specifically a device for a device (such as a transmitting device or a receiving device), for example, when the communication device 500 is specifically a chip or a chip system, the baseband signal can be output or received by the communication interface 520. When the communication device 500 is specifically a device (such as a transmitting device or a receiving device), the radio frequency signal can be output or received by the communication interface 520. In the embodiments of the present application, the processor can be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor can be a microprocessor or any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0128] It should be noted that the above communication interface 520 can be used to execute the functions of the foregoing interface unit 402, and the above processor 510 can be used to execute the functions of the foregoing processing unit 401, which will not be elaborated here.

[0129] It can be understood that the processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0130] The method steps in the embodiments of the present application can be implemented in a hardware manner or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a random access memory (RAM), flash memory, read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), register, hard disk, removable hard disk, CD-ROM, or any other form of storage medium well-known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to 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. Additionally, the ASIC can be located in a network device or a terminal device. Of course, the processor and the storage medium can also exist as discrete components in a transmitting device or a receiving device.

[0131] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using 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 instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer program or instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server integrating one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a DVD; or it can be a semiconductor medium, such as a solid state disk (SSD).

[0132] In various embodiments of the present application, if there is no special description and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0133] It should be understood that the various numerical 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 magnitudes of the serial numbers of the above processes do not mean the sequence of execution, and the execution sequence of each process should be determined by its function and internal logic.

[0134] The embodiments of the present application further provide a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed, the methods executed by the terminal device or the network device in the above method embodiments are implemented.

[0135] The embodiments of the present application further provide a computer program product, which includes a computer program. When the computer program is executed, the methods executed by the sending device or the receiving device in the above method embodiments are implemented.

[0136] The embodiments of the present application further provide a communication system, which includes a sending device or a receiving device. Among them, the sending device is used to execute the method executed by the sending device in the above method embodiments. The receiving device is used to execute the method executed by the receiving device in the above method embodiments.

[0137] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be adopted in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0138] The descriptions of the embodiments provided in the present application can be referred to each other. The descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. For the convenience and conciseness of description, for example, the functions and executed steps of the various devices and equipment provided in the embodiments of the present application can refer to the relevant descriptions of the method embodiments of the present application. The method embodiments can also refer to, combine or cite each other between the device embodiments.

[0139] 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 them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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 includes: When the reason for random access failure is preamble mismatch, determining a first index difference, where the first index difference is the difference between a first index and a second index, the first index being the index of the first preamble sent, and the second index being the preamble index in the received response message; Determining an advance time amount based on the first index difference; Advancing the transmission of the first preamble based on the advance time amount.

2. The method according to claim 1, characterized in that The determining an advance time amount based on the first index difference includes: When the reason for consecutive N random access failures is preamble mismatch, determining the advance time amount based on the first index difference, where N is a positive integer greater than 0.

3. The method according to claim 2, characterized in that The determining the advance time amount when the reason for consecutive N random access failures is preamble mismatch and based on the first index difference includes: When the reason for consecutive N random access failures is preamble mismatch and the index differences in the consecutive N random access failures are all within a preset range, determining the advance time amount based on the first index difference.

4. The method according to claim 2 or 3, characterized in that, The determining an advance time amount based on the first index difference includes: Determining the advance time amount based on the first index difference, the sequence length of the first preamble, the unit cyclic shift amount of the first preamble, and the subcarrier spacing.

5. The method according to claim 4, wherein After advancing the transmission of the first preamble based on the advance time amount, the method further includes: If random access fails, adding the cell corresponding to the network device to a blacklist.

6. The method according to claim 5, characterized in that The adding the cell corresponding to the network device to a blacklist if random access fails, the method further includes: If random access fails and the number of random access failures is greater than a preset threshold, adding the cell corresponding to the network device to a blacklist.

7. A communication device, characterized in that, Includes a unit for executing the method according to any one of claims 1 to 6.

8. A chip system, characterized in that, Includes a processor and a memory, the processor and the memory being coupled, and the processor being used to implement the method according to any one of claims 1 to 6.

9. A chip, characterized in that, Includes a processor and an interface, the processor and the interface being coupled; the interface is used to receive or output signals, and the processor is used to execute code instructions to cause the method according to any one of claims 1 to 6 to be executed.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which when called, cause the computer to execute the method according to any one of claims 1 to 6.

Images