A method and apparatus for random access collision handling

Abstract

The application discloses a method and device for random access collision processing. The method comprises the following steps: a network side device generates and sends a lightweight control message in response to detecting that a first message collision occurs on a random access occasion, the lightweight control message being used for dynamically indicating a set of one-time use additional random access occasions; a terminal side device starts a listening window after sending the first message, listens and parses the lightweight control message in response to not successfully detecting a valid second message in the listening window, randomly selects a random access occasion from the additional random access occasions, and retransmits the first message; and the network side device receives the retransmitted first message and performs a random access process. The application dynamically schedules one-time additional random access resources by adding a lightweight control message, realizes fast retransmission after collision, reduces retransmission delay, avoids periodic resource waste, improves system resource utilization, and is highly compatible with an existing random access process.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a method and apparatus for random access collision processing. Background Technology

[0002] In 5G NR Release 19, a time-domain PRACH resource adaptation mechanism was introduced to address PRACH collision issues under high access load scenarios. This mechanism, at its core, uses a "semi-static configuration + dynamic indication" approach to mitigate the probability of collisions under high access pressure, improve the initial access success rate, and reduce access latency. Its implementation involves two levels: First, the gNB semi-statically configures a set of additional PRACH resources (i.e., additional RO, RACH Occasion, random access timing) as backups through the RACH-ConfigCommon field in SIB1 (System Information Block 1). These resources are not activated by default and are only enabled when access load increases. Second, when the gNB detects increased access load (e.g., PRACH collision rate exceeding a threshold), it dynamically instructs the UE to enable the aforementioned additional PRACH resources through paging the PDCCH or PDCCH commands. After receiving the indication, the UE initiates PRACH transmission (Msg1) on the additional RO, achieving access offloading.

[0003] Although the R19 time-domain PRACH resource adaptation mechanism mentioned above can alleviate initial Msg1 collisions under high access load, its efficiency is significantly insufficient in Msg1 retransmission scenarios, and it cannot meet the requirements for low-latency retransmission. The specific defects are as follows: 1) Fixed configuration mode: The additional RO of R19 is a periodic resource configured semi-statically through SIB1. Once activated, it will reappear at a fixed period. It is impossible to dynamically allocate "one-time, temporary" RO resources for a single collision event, resulting in poor adaptability. 2) High activation latency: From gNB detecting PRACH collision, to activating additional RO via paging PDCCH or PDCCH Order, to UE receiving indication and initiating retransmission, the entire process takes a long time and cannot meet the low latency requirement of Msg1 retransmission. 3) Serious waste of resources: If a single collision event activates periodic additional ROs, these periodic resources will continue to exist after the collision problem is resolved, resulting in the ineffective occupation of uplink resources and reducing the overall resource utilization of the system.

[0004] Furthermore, in LTE and NR systems, the traditional RACH collision handling relies entirely on the Msg3 / Msg4 contention resolution process. UEs that are not decoded after a collision need to experience a long delay before they can re-initiate access. This forces operators to configure excessive RO resources to reduce the probability of collisions, further exacerbating the waste of uplink resources. The existing R19 mechanism has not solved this core pain point. Summary of the Invention

[0005] This application proposes a method and device for random access collision handling, which solves the problems of fixed configuration mode, high activation latency and serious resource waste in the existing PRACH resource adaptation mechanism under Msg1 retransmission scenario. It is especially suitable for rapid recovery of PRACH collision under high access load scenario.

[0006] Firstly, this application proposes a method for random access collision handling, comprising the following steps: In response to detecting a first message collision on a random access opportunity, the network-side device generates and sends a lightweight control message, which is used to dynamically indicate a set of additional random access opportunities for one-time use. After sending the first message, the terminal device opens a listening window. In response to the failure to successfully detect a valid second message in the listening window, it listens for and parses the lightweight control message, randomly selects a random access opportunity from the additional random access opportunities, and retransmits the first message. The network-side device receives the first message retransmitted by the terminal-side device during the additional random access opportunity, and in response to successfully receiving the retransmitted first message, executes the random access procedure.

[0007] The method described in any embodiment of the first aspect of this application, used in a network-side device, includes the following steps: In response to the detection of a first message collision on a random access opportunity, a lightweight control message is generated, which is used to dynamically indicate a set of additional random access opportunities for one-time use; Send the lightweight control message; The receiving terminal retransmits the first message at the additional random access opportunity; In response to successfully receiving the first retransmitted message, a random access procedure is executed.

[0008] The method described in any embodiment of the first aspect of this application, used in a terminal-side device, includes the following steps: After sending the first message, open the listening window; In response to the failure to detect a valid second message within the listening window, a lightweight control message is listened for, which is used to dynamically indicate a set of one-time additional random access opportunities; Parse the lightweight control message to obtain information about the additional random access timing; Randomly select one of the additional random access opportunities and retransmit the first message.

[0009] Furthermore, in the method described in this application, the lightweight control message is sent using a combination of physical downlink control channel and physical downlink shared channel, and is sent to the terminal where the first message collision occurs via common signaling.

[0010] Furthermore, in the method described in this application, the time-frequency position of the additional random access opportunity is dynamically determined in real time based on the current air interface resource status and the sending position of the lightweight control message, without the need for pre-configuration through system information blocks.

[0011] Furthermore, in the method described in this application, the modulation and coding scheme of the lightweight control message adopts low-order modulation, the transmission power is adapted to the coverage range of the target cell, and it only carries the time-frequency location and quantity information of the additional random access opportunity, without carrying the preamble sequence selection and power control parameters.

[0012] Furthermore, in the method described in this application, the additional random access opportunity is a one-time resource, used only for the retransmission of the first message collision, and automatically expires after use, and does not recur at a fixed period.

[0013] Furthermore, in the method described in this application, the terminal device, upon determining that it is in a collision state if no second message is detected within the listening window, listens to the lightweight control message without detecting it simultaneously with the second message.

[0014] Furthermore, the method described in any embodiment of the first aspect of this application, used by a network-side device, detects a first message collision occurring during random access, including: detecting multiple spatial paths or temporal peaks of the same first message preamble at the physical random access channel receiver, and determining that a first message collision has occurred.

[0015] Furthermore, the method described in any embodiment of the first aspect of this application, when used in a terminal-side device, retransmits the first message, retains the preamble sequence selection and power control configuration of the physical random access channel, and only changes the random access timing position of the physical random access channel transmission.

[0016] Secondly, this application also proposes a network-side device for implementing the method described in any one of the first aspects of this application. At least one module in the network-side device is configured to perform at least one of the following functions: in response to detecting a first message collision on a random access opportunity, generating a lightweight control message, the lightweight control message being used to dynamically indicate a set of one-time additional random access opportunities; sending the lightweight control message; receiving a first message retransmitted by a terminal on the additional random access opportunity; in response to successfully receiving the retransmitted first message, executing a random access procedure; and determining that a first message collision has occurred by detecting multiple spatial paths or temporal peaks of the same first message preamble at a physical random access channel receiver.

[0017] Thirdly, this application also proposes a terminal-side device for implementing the method described in any one of the first aspects of this application. At least one module in the terminal-side device is configured to perform at least one of the following functions: after sending a first message, opening a listening window; in response to the failure to successfully detect a valid second message within the listening window, listening for a lightweight control message, the lightweight control message being used to dynamically indicate a set of one-time additional random access opportunities; parsing the lightweight control message to obtain information about the additional random access opportunities; randomly selecting a random access opportunity from the additional random access opportunities and retransmitting the first message; when retransmitting the first message, using the preamble sequence selection and power control configuration of the physical random access channel, only changing the position of the random access opportunity transmitted through the physical random access channel.

[0018] Fourthly, this application also proposes a communication device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the method as described in any embodiment of the first aspect of this application.

[0019] Fifthly, this application also proposes a computer-readable medium on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in any embodiment of the first aspect of this application.

[0020] Sixthly, this application also proposes a mobile communication system comprising at least one network-side device as described in any embodiment of this application and / or at least one terminal-side device as described in any embodiment of this application.

[0021] The above-described technical solutions adopted in the embodiments of this application can achieve the following beneficial effects: After adopting the enhanced scheme of this embodiment, the retransmission latency after Msg1 collision is reduced compared with the existing R19 mechanism; temporary RO resources are only used during collision retransmission, without periodic resource waste, and uplink resource utilization is improved; at the same time, since the subsequent process completely reuses the traditional RACH process, the protocol modification is minimal and can be quickly adapted to the deployment of existing 5G NR R19 systems.

[0022] Specifically, the technical solution of this application has the following advantages compared with the prior art: 1) Low-latency retransmission: MsgX skips complex processes such as SIB1 configuration and paging, and can be sent quickly, ensuring that the UE can receive and prepare for retransmission in a timely manner. The transmission latency is on the same order of magnitude as Msg2, which is much lower than the activation latency of the R19 mechanism.

[0023] 2) High resource utilization: The extra RO indicated by MsgX is only used for the retransmission of Msg1 in this collision event. It is a one-time resource and will automatically expire after use. It will not reappear at a fixed period, thus avoiding periodic resource waste.

[0024] 3) Strong protocol compatibility: After a successful retransmission, the subsequent access process follows the traditional RACH process without any modification to Msg2 / Msg3 / Msg4, and can be quickly adapted to the deployment of existing 5G NR R19 systems.

[0025] 4) Low risk of secondary collision: The UE randomly selects an RO from the additional RO set indicated by MsgX for retransmission, avoiding secondary collision caused by multiple colliding UEs selecting the same RO again. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart illustrating an overall embodiment of the random access collision handling method of this application; Figure 2 This is a schematic diagram of the retransmission response after a collision; Figure 3 This is a flowchart illustrating an embodiment of the method of this application used in a network-side device; Figure 4 This is a flowchart illustrating an embodiment of the method of this application used in a terminal-side device; Figure 5 This is a schematic diagram of the functional modules of a network-side device embodiment; Figure 6 This is a schematic diagram of the functional modules of an embodiment of a terminal-side device; Figure 7This is a schematic diagram of the structure of a network-side device according to another embodiment of the present invention; Figure 8 This is a block diagram of a terminal-side device according to another embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The core concept of this application is to abandon the semi-static periodic configuration method of additional ROs in the R19 mechanism, and dynamically and temporarily schedule a set of one-time use additional ROs by sending a new control message MsgX through gNB. This is specifically used for Msg1 retransmission after PRACH collision, realizing a closed loop of "collision detection - real-time scheduling - one-time use - process compatibility". This solves the low-latency retransmission requirement and avoids resource waste.

[0029] The technical solution of this application has the following innovative features on both the network side and the terminal side: Network-side innovation features include: Collision detection and instant triggering mechanism: The PRACH receiver detects multiple spatial paths or temporal peaks with the same preamble, determines Msg1 collision in real time, and immediately triggers the enhancement mechanism without waiting for load threshold or paging process. Dynamic one-time RO scheduling: Based on the current air interface resource status and MsgX transmission location, additional ROs for one-time use are dynamically allocated in real time without the need for SIB1 pre-configuration; Added MsgX generation and fast transmission: adopts PDCCH+PDSCH combination and cell-level broadcast method, fast transmission in the most recent downlink subframe, and the transmission parameters are determined in real time; Resource adaptation and subsequent process handling: When allocating additional ROs, avoid already occupied resources, adapt the quantity to the estimated number of UEs, and execute the traditional RACH process after successful retransmission.

[0030] The innovative features on the terminal side include: MsgX listening trigger condition optimization: MsgX is only listened to when Msg2 is not detected in the Msg2 listening window and a collision state is determined, and is not detected at the same time as Msg2; MsgX reception and parsing: Receive and parse the MsgX sent by gNB to obtain temporary RO set information; Random RO selection mechanism: Randomly select an RO from a temporary RO set to reduce the risk of secondary collisions; Msg1 retransmission mechanism: Retransmit the PRACH preamble on the selected RO, using the traditional preamble sequence and power control, only changing the RO position; Closed-loop interaction with MsgX: Listen to and respond to MsgX under specific conditions to achieve a closed loop of "collision detection → real-time scheduling → fast retransmission".

[0031] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0032] For ease of description, this application uses the following names to uniformly name the relevant messages in the machine access process: The first message refers to the Random Access Preamble sent by the terminal device to the network device, which corresponds to Msg1 in the traditional random access procedure. This message is carried on the Physical Random Access Channel (PRACH) and is used to initiate a random access request.

[0033] The second message refers to the Random Access Response (RAR) sent by the network-side device to the terminal-side device in response to the first message. In the traditional random access procedure, it corresponds to Msg2. This message is carried on the Physical Downlink Shared Channel (PDSCH) and scheduled by the Physical Downlink Control Channel (PDCCH). It is used to provide the terminal-side device with information such as timing advance, uplink grant, and temporary C-RNTI.

[0034] Lightweight Control Message (hereinafter referred to as MsgX): A control message added in this application, used to dynamically indicate a set of one-time additional random access opportunities (ROs). This message is sent using a combination of PDCCH and PDSCH and broadcast to the terminal where the first message collision occurs via common signaling. It only carries the time-frequency location and quantity information of the additional ROs and does not carry complex access parameters such as preamble sequence selection and power control.

[0035] Random Access Occasion (RO): refers to the time-frequency resource location at which the terminal device sends the first message, including a specific time slot in the time domain and a specific physical resource block in the frequency domain.

[0036] Figure 1 This is a flowchart illustrating an overall embodiment of the random access collision handling method of this application. This application proposes a method for random access collision handling, which describes the collaborative interaction process between network-side devices and terminal-side devices from a system-wide perspective. The method includes the following steps 110-130: Step 110: In response to detecting a first message collision on a random access opportunity, the network-side device generates and sends a lightweight control message, which is used to dynamically indicate a set of one-time additional random access opportunities.

[0037] In this step, the "first message" refers to Msg1 in the traditional random access procedure, i.e., the random access preamble sent by the terminal device to the network device. The "random access occasion" (RO) is the time-frequency resource location at which the terminal device sends the first message. The "lightweight control message" (hereinafter referred to as MsgX) is a control message added in this application, used to dynamically indicate a set of additional random access occasions for one-time use.

[0038] In one specific embodiment, after the gNB detects a Msg1 collision on a certain RO through the PRACH receiver, it immediately triggers an enhancement mechanism to generate and send MsgX. A "collision" refers to multiple UEs sending the same preamble sequence on the same RO, causing the gNB to be unable to correctly distinguish between the UEs. The gNB detects collisions by detecting multiple spatial paths or temporal peaks of the same PRACH preamble through the PRACH receiver and determining it as a UE collision (rather than multipath transmission) based on signal characteristics (such as signal strength and time difference of arrival).

[0039] The time-frequency location of the additional RO is dynamically determined in real time by the gNB based on the current air interface resource status and the transmission location of MsgX, without prior configuration via SIB1. For example, after detecting a collision, the gNB immediately checks the current uplink resource usage, avoids already occupied time-frequency resource blocks, and selects a set of idle RO resources as temporary additional ROs. The generation and transmission of MsgX do not require SIB1 configuration or paging procedures, and the transmission latency is on the same order of magnitude as Msg2.

[0040] Step 120: After sending the first message, the terminal device opens a listening window. In response to the failure to successfully detect a valid second message in the listening window, it listens for and parses the lightweight control message, randomly selects a random access opportunity from the additional random access opportunities, and retransmits the first message.

[0041] In this step, the "listening window" refers to the Msg2 listening window (RAResponse Window) in the traditional random access procedure, used to receive the network-side device's response to the first message. The "second message" refers to Msg2 in the traditional random access procedure, that is, the random access response (RAR) sent by the network-side device to the terminal-side device in response to the first message.

[0042] In one specific embodiment, a UE that has sent Msg1 on the collision RO first enters the Msg2 listening window and focuses on detecting its own corresponding Msg2. When Msg2 is not detected within the Msg2 listening window, the UE determines that it is in a collision state, starts the MsgX receiving and parsing module, and listens for and parses the MsgX sent by the gNB in ​​the cell. The UE only listens for MsgX when it does not detect Msg2 within the Msg2 listening window and determines that it is in a collision state; it does not detect MsgX simultaneously with Msg2.

[0043] The UE parses the additional RO set information carried in MsgX to obtain the time-frequency positions of all available temporary ROs. Then, the UE randomly selects an RO from this additional RO set and retransmits its own PRACH preamble, thus completing the Msg1 retransmission (also known as MsgY). During the retransmission, the UE uses the traditional PRACH configuration, including preamble sequence selection and power control, only changing the RO positions for PRACH transmission. This random selection mechanism effectively avoids secondary collisions caused by multiple colliding UEs selecting the same RO again.

[0044] Step 130: The network-side device receives the first message retransmitted by the terminal-side device during the additional random access opportunity, and in response to successfully receiving the first retransmitted message, executes the random access procedure.

[0045] In one specific embodiment, if the gNB successfully receives the PRACH preamble retransmitted by the UE, it follows the traditional RACH procedure, sequentially sending Msg2, receiving Msg3, and sending Msg4 to resolve the contention and advance subsequent access. The subsequent access procedure completely reuses the traditional RACH procedure, requiring no additional modifications to the subsequent process, resulting in minimal protocol changes.

[0046] It should be noted that the above steps are used for network entities in a wireless communication system, including terminal-side devices, network-side devices, or other intermediate devices; the above steps can also be used for service devices that provide information processing for the network entity devices; the above steps can also be used for any device, system, subsystem, circuit, chip, or software entity that provides information reception, transmission, identification, and processing for terminal-side devices or network-side devices.

[0047] Figure 2 This diagram illustrates the retransmission response after a collision. As shown, when multiple UEs collide while transmitting Msg1 on the same RO, the gNB detects the collision and sends MsgX. After receiving MsgX, the UE retransmits Msg1 on a temporary RO. The gNB responds with Msg2, completing subsequent access. The diagram clearly demonstrates the complete closed loop of this application: "collision detection - real-time scheduling - one-time use - process compatibility".

[0048] Figure 3 This is a flowchart illustrating an embodiment of the method of this application used in a network-side device. The method described in any embodiment of the first aspect of this application, used in a network-side device, includes the following steps 210-240: Step 210: In response to the detection of a first message collision on a random access opportunity, a lightweight control message is generated, which is used to dynamically indicate a set of additional random access opportunities for one-time use.

[0049] In one specific embodiment, the gNB's PRACH receiver detects the signals of each RO in real time. When multiple spatial paths with the same PRACH preamble are detected on a certain RO, and the signal characteristics (such as signal strength and time difference of arrival) determine that it is a UE collision (rather than multipath transmission), the enhancement mechanism of the present invention is immediately triggered without waiting for the access load to continue to rise or without going through the paging process.

[0050] Upon detecting a collision, the gNB immediately generates MsgX. The generation and transmission of MsgX do not require SIB1 configuration or paging procedures, and the transmission latency is on the same order of magnitude as Msg2. The time-frequency location of the additional ROs is dynamically determined by the gNB in ​​real time based on the current air interface resource status and the transmission location of MsgX, without prior configuration via SIB1. For example, the gNB-side RO scheduling module, based on the current air interface uplink resource occupancy, avoids already occupied resources and, combined with the time-frequency location of the upcoming MsgX, dynamically allocates several temporary additional ROs. The number of these ROs is adapted to the estimated number of UEs involved in the collision, ensuring sufficient resources without waste.

[0051] Step 220: Send the lightweight control message.

[0052] In one specific embodiment, MsgX is scheduled for transmission via the downlink control channel and sent to the terminal involved in the Msg1 collision using common signaling. It is immediately scheduled for transmission in the nearest downlink subframe after the gNB completes the dynamic allocation of additional ROs and generates MsgX. The transmission mechanism of MsgX references the fast transmission logic of Msg2. However, unlike Msg2, which is a directed response to a single UE, MsgX is a broadcast lightweight control message aimed at all UEs within the collision event coverage area.

[0053] Specifically, MsgX is sent as follows: Transmission channel selection: Referencing Msg2, a transmission combination of PDCCH (Physical Downlink Control Channel) + PDSCH (Physical Downlink Shared Channel) is used. PDCCH is used to carry the scheduling information of MsgX (such as transmission time and resource location), and PDSCH is used to carry the specific content of MsgX (time and frequency location and number of additional ROs). The scrambling method of PDCCH is the common RNTI.

[0054] Transmission timing: Referring to the logic of Msg2 responding quickly after the UE transmits Msg1, after the gNB detects the Msg1 collision and completes the dynamic allocation of additional RO and the generation of MsgX, it immediately schedules PDCCH and PDSCH resources in the nearest downlink subframe to transmit MsgX without waiting for a fixed period, ensuring that the UE can receive and parse it in the shortest possible time, thus meeting the low-latency retransmission requirement of Msg1.

[0055] Transmission range: Cell-level broadcast transmission is used to cover the target cell where the Msg1 collision occurred, ensuring that all UEs that have transmitted Msg1 on the RO of the collision can receive MsgX; there is no need to send to a single UE, simplifying the transmission logic, reducing the processing overhead on the gNB side, and avoiding the increase in latency caused by targeted transmission.

[0056] Transmission parameter adaptation: Referring to the transmission parameter configuration logic of Msg2, MsgX adopts low-order modulation (such as QPSK) in its modulation and coding scheme (MCS) to ensure the reliability of UE reception, while reducing the complexity of encoding and decoding, and further shortening the UE parsing latency; the transmission power is adapted to the cell coverage range, without the need for excessive power, balancing resource overhead and reception effect.

[0057] The difference between MsgX and Msg2 is as follows: Msg2 is a response message sent by the gNB to a single UE for Msg1, carrying access-related parameters such as RAR, and is used for access guidance of a single UE; while MsgX is a broadcast message for a single collision event, carrying only additional RO key information, not involving the access parameters of a single UE, lightweight and with a wider transmission range, and its core objective is to quickly schedule temporary RO for Msg1 retransmission.

[0058] MsgX sending is characterized by its dynamic, one-time, low-latency, and lightweight nature. Dynamics: The time-frequency location of the additional RO is dynamically determined in real time by the gNB based on factors such as the current air interface resource status and the transmission location of MsgX, without the need for semi-static configuration via SIB1 in advance; One-time use: The RO set indicated by MsgX is only used for the retransmission of Msg1 in this collision event. It is a one-time resource and will automatically expire after use. It will not reappear at a fixed period. Low latency: MsgX skips complex processes such as SIB1 configuration and paging, and can send quickly, ensuring that the UE can receive in time and prepare for retransmission; Lightweight: MsgX only carries key information such as the time and frequency location and number of additional ROs, without carrying complex access parameters, thus reducing signaling overhead.

[0059] Step 230: Receive the first message retransmitted by the receiving terminal at the additional random access opportunity.

[0060] In one specific embodiment, the gNB listens for and receives the PRACH preamble for UE retransmissions on the additional ROs. Since the additional ROs are one-time resources, the gNB only needs to listen to these ROs during the retransmission phase of this collision event, without needing to occupy the resources for an extended period.

[0061] Step 240: In response to successfully receiving the first retransmitted message, execute the random access procedure.

[0062] In one specific embodiment, if the gNB successfully receives the PRACH preamble retransmitted by the UE, it follows the traditional RACH procedure, sequentially sending Msg2, receiving Msg3, and sending Msg4 to resolve contention and advance subsequent access. The Msg2 sent by the gNB includes information such as the temporary C-RNTI, timing advance (TA), and uplink grant (UL Grant). After receiving this, the UE sends Msg3 (RRC connection request), and the gNB then sends Msg4 (contention resolution message) to complete the entire access process.

[0063] Figure 4 This is a flowchart illustrating an embodiment of the method of this application used in a terminal-side device. The method described in any embodiment of the first aspect of this application, used in a terminal-side device, includes the following steps 310-340: Step 310: After sending the first message, open the listening window.

[0064] In one specific embodiment, after sending Msg1, the UE opens a Msg2 listening window (RA ResponseWindow) to focus on detecting its own corresponding Msg2. The length of the listening window is configured by the network side through system information, and is usually several time slots or subframes. Within the listening window, the UE continuously listens to the PDCCH, checking whether there is a PDCCH scrambled with RA-RNTI (Random Access Radio Network Temporary Identifier) ​​scheduling Msg2, and whether the preamble identifier (RAPID) in Msg2 matches the preamble it sent.

[0065] Step 320: In response to the failure to detect a valid second message within the listening window, listen for a lightweight control message, which is used to dynamically indicate a set of one-time additional random access opportunities.

[0066] In one specific embodiment, when the UE fails to detect the corresponding Msg2 within the Msg2 listening window, it determines that it is in a collision state and activates the MsgX receiving and parsing module to listen for and parse the MsgX sent by the gNB in ​​the cell. The UE only listens for MsgX when it fails to detect Msg2 within the Msg2 listening window and determines that it is in a collision state, and does not detect MsgX simultaneously with Msg2. This design avoids unnecessary MsgX listening by the UE during normal access, reducing the UE's power consumption and processing complexity.

[0067] Listening to MsgX requires the UE to know the PDCCH scrambling method of MsgX. In one embodiment, MsgX is scrambled using a common RNTI (such as SI-RNTI or a newly defined RNTI). After collision detection, the UE starts listening to the PDCCH scheduled by this RNTI to obtain the scheduling information of MsgX, and then receives the MsgX content on the PDSCH.

[0068] Step 330: Parse the lightweight control message to obtain information about the additional random access timing.

[0069] In one specific embodiment, the UE parses the additional RO set information carried in MsgX to obtain the time-frequency positions of all available temporary ROs. The content format of MsgX can be designed to include: the number of additional ROs (N), the time-domain position of each RO (such as system frame number, time slot index), and the frequency-domain position (such as physical resource block index). Since MsgX only carries this key information and does not carry complex access parameters such as preamble sequence selection and power control, the signaling overhead is extremely small, and transmission and decoding are very efficient.

[0070] Step 340: Randomly select a random access opportunity from the additional random access opportunities and retransmit the first message.

[0071] In one specific embodiment, the UE randomly selects an RO from the additional RO set and retransmits its own PRACH preamble, thus completing the Msg1 retransmission (also known as MsgY). This random selection mechanism avoids secondary collisions caused by multiple colliding UEs selecting the same RO again. During retransmission, the UE uses the traditional PRACH configuration, including preamble sequence selection and power control, only changing the RO position in the PRACH transmission. This means the UE does not need to reselect the preamble sequence (it can use the previously transmitted preamble sequence) nor does it need to recalculate open-loop power control; it can directly use the original transmit power or fine-tune it according to the PRACH power control formula.

[0072] After the UE completes the Msg1 retransmission, it re-enters the Msg2 listening window and waits for the gNB's response. If the gNB successfully receives the retransmitted Msg1, the UE will receive Msg2 and then continue with the subsequent Msg3 / Msg4 process to complete the access.

[0073] Figure 5 This is a schematic diagram of the functional modules of a network-side device embodiment. This application also proposes a network-side device for implementing the method of any embodiment of this application, wherein the network-side device is used for: To implement the above technical solution, this application proposes a network-side device 400, which includes a network transmitting module 401, a network determining module 402, and a network receiving module 403 that are interconnected.

[0074] The network sending module 401 is used to send lightweight control messages, which dynamically indicate a set of one-time additional random access opportunities; send random access responses (Msg2), etc. This module can perform the sending operations in steps 220 and 240, as well as send Msg2.

[0075] The network determination module 402 is configured to generate a lightweight control message in response to the detection of a first message collision during a random access opportunity; determine that a first message collision has occurred by detecting multiple spatial paths or temporal peaks with the same first message preamble at the physical random access channel receiver; and dynamically determine the time-frequency position of an additional random access opportunity in real time based on the current air interface resource status and the transmission position of the lightweight control message. This module can execute step 210, the collision determination operation, and the reception parsing operation in step 230.

[0076] The network receiving module 403 is used to receive the first message retransmitted by the terminal during the additional random access opportunity; and to receive Msg3, etc., sent by the terminal. This module can perform the receiving operation in step 230.

[0077] The specific methods for implementing the functions of the network sending module, network determining module, and network receiving module are as described in the various method embodiments of this application, and will not be repeated here.

[0078] The network-side equipment described in this application may refer to base station facilities, network-side equipment or servers connected to base stations, systems that provide services for the aforementioned equipment, or any system, subsystem, module, circuit, chip or software operating device that provides information reception, transmission, identification and processing for the aforementioned equipment.

[0079] Figure 6 This is a schematic diagram of an embodiment of a terminal-side device. This application also proposes a terminal-side device for implementing the method of any embodiment of this application, wherein the terminal-side device is used for: To implement the above technical solution, this application proposes a terminal-side device 500, which includes a terminal transmitting module 501, a terminal determining module 502, and a terminal receiving module 503 that are interconnected.

[0080] The terminal receiving module 503 is configured to open a listening window after sending the first message; listen for lightweight control messages in response to the failure to successfully detect a valid second message within the listening window; and receive random access responses (Msg2), etc. This module can perform the listening operations in steps 310 and 320.

[0081] The terminal determination module 502 is used to parse the lightweight control message, obtain information about the additional random access opportunities, and randomly select a random access opportunity from the additional random access opportunities. This module can perform the selection operations in steps 330 and 340.

[0082] The terminal sending module 501 is used to retransmit the first message at a selected random access time; and to send the first message (Msg1) and Msg3, etc. This module can perform the sending operation in step 310 and the retransmission operation in step 340.

[0083] The specific methods for implementing the functions of the terminal sending module, the terminal determining module, and the terminal receiving module are as described in the various method embodiments of this application, and will not be repeated here.

[0084] The terminal-side equipment described in this application may refer to user equipment (UE), personal mobile terminal, smart terminal, mobile phone, computer with communication function, system that provides services for the above-mentioned equipment, or any system, subsystem, module, circuit, chip or software running device that provides information reception, transmission, identification and processing for the above-mentioned equipment.

[0085] Figure 7 A schematic diagram of a network-side device according to another embodiment of the present invention is shown. As shown, the network-side device 600 includes a processor 601, a wireless interface 602, and a memory 603. The wireless interface may consist of multiple components, including a transmitter and a receiver, providing a unit for communication with various other devices over a transmission medium. The wireless interface implements communication functions with the terminal-side device, processes wireless signals through receiving and transmitting devices, and the data carried by the signals is communicated with the memory or processor via an internal bus structure. The memory 603 contains a computer program that executes any embodiment of this application, and the computer program runs or modifies the processor 601. When the memory, processor, and wireless interface circuit are connected through a bus system, the bus system includes a data bus, a power bus, a control bus, and a status signal bus, which will not be described in detail here.

[0086] Figure 8 This is a block diagram of a terminal-side device according to another embodiment of the present invention. The terminal-side device 700 includes at least one processor 701, a memory 702, a user interface 703, and at least one wireless network interface 704. The various components in the terminal-side device 700 are coupled together via a bus system. The bus system is used to enable communication between these components. The bus system includes a data bus, a power bus, a control bus, and a status signal bus.

[0087] User interface 703 may include a display, keyboard, or clicking device, such as a mouse, trackball, touchpad, or touchscreen.

[0088] The memory 702 stores executable modules or data structures. The memory may store an operating system and application programs. The operating system includes various system programs, such as a framework layer, core library layer, and driver layer, used to implement various basic business functions and handle hardware-based tasks. The application programs include various applications, such as media players and browsers, used to implement various application functions.

[0089] In an embodiment of the present invention, the memory 702 contains a computer program that executes any embodiment of the present application, the computer program being run on or modified by the processor 701.

[0090] The memory 702 includes a computer-readable storage medium. The processor 701 reads the information in the memory 702 and, in conjunction with its hardware, completes the steps of the above-described method. Specifically, the computer-readable storage medium stores a computer program, which, when executed by the processor 701, implements the steps of the method embodiments described in any of the above embodiments.

[0091] Processors 601 and 701 may be integrated circuit chips with signal processing capabilities. In implementation, each step of the method in this application can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, digital signal processor, application-specific integrated circuit, off-the-shelf programmable gate array or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this invention can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor.

[0092] Regarding the timing of the lightweight control message MsgX transmission in the method of this application, at time t0, multiple UEs collide while transmitting Msg1 on the same RO. The gNB detects the collision at time t1 and immediately transmits MsgX at time t2 (the most recent downlink subframe). The UE receives and parses MsgX at time t3 and retransmits Msg1 at time t4 (on the temporary RO indicated by MsgX). The gNB responds to Msg2 at time t5, the UE transmits Msg3 at time t6, and the gNB transmits Msg4 at time t7 to complete the access. Throughout the entire process, the transmission delay of MsgX is on the same order of magnitude as that of Msg2, which is much lower than the delay of activating an additional RO through paging in the R19 mechanism.

[0093] Regarding the state machine of the UE-side listening and retransmission process in this application, the UE enters the "Waiting for Msg2" state after sending Msg1. If Msg2 is received within the listening window, it enters the "Subsequent Access" state. If Msg2 is not received within the listening window timeout, it enters the "Collision Determination" state and then starts MsgX listening. If MsgX is received, it enters the "Temporary RO Selection" state, randomly selects a temporary RO, enters the "Retransmit Msg1" state, and then returns to the "Waiting for Msg2" state. If MsgX is not received during MsgX listening (i.e., the gNB does not detect a collision or does not send MsgX), the UE can fall back to the traditional retransmission mechanism (such as retransmitting after increasing the preamble transmit power).

[0094] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. In a typical configuration, the device of this application includes one or more processors (CPUs), an input / output user interface, a network interface, and memory.

[0095] Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] Therefore, this application also proposes a computer-readable medium storing a computer program that, when executed by a processor, implements the steps of the method described in any embodiment of this application. For example, the memory 603, 702 of the present invention may include non-permanent memory in the form of computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM.

[0097] Based on the embodiments of the above-described apparatus in this application, this application also proposes a mobile communication system, including at least one embodiment of any terminal-side device in this application and / or at least one embodiment of any network-side device in this application.

[0098] It should be noted that the specific mobile communication technology described in this invention is not limited, and can be WCDMA, CDMA2000, TD-SCDMA, WiMAX, LTE / LTE-A, LAA, MuLTEfire, 5G NR, and the sixth-generation and Nth-generation mobile communication technologies that may appear in the future.

[0099] The terminal described in this invention refers to a terminal-side product that can support the communication protocols of terrestrial mobile communication systems, specifically a wireless modem module that can be integrated into various types of terminal forms such as mobile phones, tablets, and data cards to complete communication functions.

[0100] For ease of description, a fifth-generation mobile communication system is used as an example, where the mobile communication terminal can be represented as UE (User Equipment), and the network-side access equipment can be represented as a base station or access point.

[0101] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0102] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be understood that when a device or component is “connected” to another device or component, it may be directly connected to the other device or component, or there may be an intermediary device or component. Furthermore, the term “connection” as used herein may include partially wireless connections as well as partially wired connections.

[0103] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0104] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for random access collision handling, characterized in that, Includes the following steps: In response to detecting a first message collision on a random access opportunity, the network-side device generates and sends a lightweight control message, which is used to dynamically indicate a set of additional random access opportunities for one-time use. After sending the first message, the terminal device opens a listening window. In response to the failure to successfully detect a valid second message in the listening window, it listens for and parses the lightweight control message, randomly selects a random access opportunity from the additional random access opportunities, and retransmits the first message. The network-side device receives the first message retransmitted by the terminal-side device during the additional random access opportunity, and in response to successfully receiving the retransmitted first message, executes the random access procedure.

2. A method for handling random access collisions, used in network-side equipment, characterized in that, Includes the following steps: In response to the detection of a first message collision on a random access opportunity, a lightweight control message is generated, which is used to dynamically indicate a set of additional random access opportunities for one-time use; Send the lightweight control message; The receiving terminal retransmits the first message at the additional random access opportunity; In response to successfully receiving the first retransmitted message, a random access procedure is executed.

3. A method for random access collision handling, used in a terminal-side device, characterized in that, Includes the following steps: After sending the first message, open the listening window; In response to the failure to detect a valid second message within the listening window, a lightweight control message is listened for, which is used to dynamically indicate a set of one-time additional random access opportunities; Parse the lightweight control message to obtain information about the additional random access timing; Randomly select one of the additional random access opportunities and retransmit the first message.

4. The method according to any one of claims 1 to 3, characterized in that, The lightweight control message is sent using a combination of physical downlink control channel and physical downlink shared channel, and is sent to the terminal where the first message collision occurs via common signaling.

5. The method according to any one of claims 1 to 3, characterized in that, The time-frequency location of the additional random access opportunity is dynamically determined in real time based on the current air interface resource status and the sending location of the lightweight control message, without the need for pre-configuration through system information blocks.

6. The method according to any one of claims 1 to 3, characterized in that, The lightweight control message uses low-order modulation and coding, and its transmission power is adapted to the target cell coverage area. It only carries the time-frequency location and quantity information of additional random access opportunities, and does not carry preamble sequence selection and power control parameters.

7. The method according to any one of claims 1 to 3, characterized in that, The additional random access opportunity is a one-time resource, used only for the retransmission of the first message collision. It will automatically expire after use and will not recur at a fixed period.

8. The method according to any one of claims 1 to 3, characterized in that, If the terminal device does not detect a second message within the listening window and determines that it is in a collision state, it listens for the lightweight control message but does not detect it simultaneously with the second message.

9. The method according to any one of claims 1 to 3, used in a network-side device, characterized in that, Detecting a first message collision during random access includes: detecting multiple spatial paths or temporal peaks of the same first message preamble at the physical random access channel receiver to determine that a first message collision has occurred.

10. The method according to any one of claims 1 to 3, used in a terminal-side device, characterized in that, When retransmitting the first message, the preamble sequence selection and power control configuration of the physical random access channel are used, only the random access timing position of the physical random access channel transmission is changed.

11. A network-side device for implementing the method according to any one of claims 1 to 10, characterized in that, At least one module in the network-side device is configured to perform at least one of the following functions: in response to detecting a first message collision on a random access opportunity, generating a lightweight control message, the lightweight control message being used to dynamically indicate a set of one-time additional random access opportunities; sending the lightweight control message; receiving a first message retransmitted by the terminal on the additional random access opportunity; in response to successfully receiving the retransmitted first message, executing a random access procedure; and determining that a first message collision has occurred by detecting multiple spatial paths or temporal peaks of the same first message preamble at the physical random access channel receiver.

12. A terminal-side device for implementing the method according to any one of claims 1 to 10, characterized in that, At least one module in the terminal-side device is configured to perform at least one of the following functions: after sending a first message, opening a listening window; in response to the failure to successfully detect a valid second message within the listening window, listening for a lightweight control message, the lightweight control message being used to dynamically indicate a set of one-time additional random access opportunities; parsing the lightweight control message to obtain information about the additional random access opportunities; randomly selecting a random access opportunity from the additional random access opportunities and retransmitting the first message; when retransmitting the first message, using the preamble sequence selection and power control configuration of the physical random access channel, only changing the position of the random access opportunity transmitted through the physical random access channel.

13. A communication device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the method as described in any one of claims 1 to 10.

14. A computer-readable medium storing a computer program that, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 10.

15. A mobile communication system, characterized in that, It includes at least one network-side device as described in claim 11 and / or at least one terminal-side device as described in claim 12.

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