Small data transmission method based on random access, user equipment and base station

Abstract

A method for small data transmission (SDT) based on random access is performed in a user equipment, comprising: receiving a configuration indicating a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters from a base station; selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship; sending a random access preamble code to the base station through the selected PRACH resource; sending a radio resource control (RRC) connection recovery request to the base station; and receiving an RRC connection release request from the base station.

Description

Technical Field

[0001] The present invention relates to the field of communication systems, and more specifically to a small data transmission method based on random access, user equipment and base station. Background Art

[0002] Wireless communication systems and networks have evolved into broadband and mobile systems. In a cellular wireless communication system, a user equipment (UE) is connected to a radio access network (RAN) via a radio link. The RAN consists of a set of base stations (BS) that provide radio links to the UEs located within the coverage area of ​​the base stations, and an interface to the core network (CN), which provides overall network control. As understood, the RAN and CN each perform their own functions for the entire network. The 3rd Generation Partnership Project (3GPP) developed the so-called Long Term Evolution (LTE) system, the Evolved Universal Mobile Telecommunications System Territorial Radio Access Network (E-UTRAN), for mobile access networks, in which one or more macro cells are supported by base stations called eNodeB or eNB (evolved NodeB). LTE is further evolving towards the so-called 5G or NR (New Radio) system, in which one or more cells are supported by base stations called gNBs.

[0003] Ultra-Reliable Low-Latency Communications (URLLC) is one of several different types of use cases supported by the 5G NR standard as specified by 3GPP Release 15. URLLC is a communication service for the successful delivery of data packets with stringent requirements, particularly in terms of availability, latency, and reliability. URLLC was developed to support emerging applications and services such as wireless control and automation in industrial factory environments, vehicle-to-vehicle communications for improved safety and efficiency, and the tactile Internet. Therefore, URLLC is important to 5G as it supports vertical industries and brings new services to the entire telecommunications industry.

[0004] One of the main features of URLLC is low latency. Low latency allows the network to be optimized to handle incredibly large amounts of data with minimal delay or latency. URLLC requires a completely different quality of service (QoS) than mobile broadband services. In addition, handling infrequent, small data traffic is one of the important scenarios for URLLC. For example, smartphones need to handle traffic from instant messaging services (whatsapp, QQ, WeChat, etc.), heartbeat / keep-alive traffic from IM / email clients, and push notifications from various applications. In addition, wearable devices require regular positioning information, industrial wireless sensor networks need to transmit temperature, pressure readings periodically or in an event-triggered manner, and smart meters and smart meter networks need to send meter readings periodically. NR supports the RRC_INACTIVE state, and user equipment with infrequent data transmission (periodic and / or aperiodic) is usually maintained in the RRC_INACTIVE state by the network. Prior to 3GPP Release 16, the RRC_INACTIVE state did not support data transmission. Therefore, the user equipment must restore the connection for any downlink (DL) and uplink (UL) data (i.e., return to the RRC_CONNECTED state). Each data transmission establishes a connection and then releases it to the RRC_INACTIVE state. However, infrequent transmission of small data packets results in unnecessary power consumption and signaling overhead. When multiple user equipments are in the RRC_INACTIVE state, contention occurs when performing small data transmissions. Therefore, reducing conflicts and controlling network congestion is a necessary task. Summary of the invention

[0005] Technical issues

[0006] Conflicts between small data transmissions (SDTs) based on random access channels (RACHs) initiated by different user equipments can lead to SDT failures and network congestion, resulting in resource waste and poor QoS assurance, which is a technical problem that needs to be solved.

[0007] Technical Solution

[0008] An object of the present invention is to provide a small data transmission method based on random access, a user equipment and a base station.

[0009] The first aspect of the present invention provides a method for small data transmission (SDT) based on random access, which is executed in a user equipment, and includes: receiving a configuration indicating a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters from a base station; selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship; sending a random access preamble code to the base station through the selected PRACH resource; sending a radio resource control (RRC) connection recovery request to the base station; and receiving an RRC connection release request from the base station.

[0010] According to an embodiment of the first aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resources includes: sending a first message to the base station through the selected PRACH resources, the first message carrying uplink UL user plane UP data and / or a random access preamble; and wherein the receiving of an RRC connection release request from the base station includes: receiving a second message from the base station, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0011] According to an embodiment of the first aspect of the present invention, sending an RRC connection recovery request to the base station includes: transmitting the RRC connection recovery request and / or UL UP data to the user equipment; and wherein receiving an RRC connection release request from the base station includes: receiving a second message from the base station, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0012] According to an embodiment of the first aspect of the present invention, the method also includes: after sending the random access preamble code to the base station, receiving a second message carrying a random access response RAR from the base station; wherein the sending of a wireless resource control RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including an RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0013] According to an embodiment of the first aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resource includes: sending a first message to the base station through the selected PRACH resource, the first message including a random access preamble and / or a UL UP authorization request or a scheduling report SR or a buffer status report BSR; wherein after the first message is sent to the base station through the selected PRACH resource, the method further includes: after sending the first message to the base station through the selected PRACH resource, receiving a second message carrying a random access response RAR and / or a UL authorization signal from the base station; wherein the sending of an RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including the RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

[0014] According to an embodiment of the first aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resources includes: sending a first message to the base station through the selected PRACH resources, the first message carrying ULUP data and / or a random access preamble; wherein after the sending of the first message to the base station through the selected PRACH resources, the method also includes: receiving a second message from the base station, the second message carrying a random access response RAR and an acknowledgment ACK signal or a negative acknowledgment NACK signal; wherein the sending of an RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including the RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or a acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0015] According to an embodiment of the first aspect of the present invention, selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship includes: measuring the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; determining a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resource is less than or equal to a configuration threshold transmitted by the base station; and selecting one of the available PRACH resources from the PRACH pool.

[0016] According to an embodiment of the first aspect of the present invention, the received signal strength strength represents reference signal received power RSRP, reference signal received quality RSRQ, received signal strength indication RSSI and / or signal to interference plus noise ratio SINR.

[0017] According to an embodiment of the first aspect of the present invention, measuring the received signal strength on the PRACH resource to obtain the measurement result of the PRACH resource includes: measuring the received signal strength on the PRACH resource to obtain the measurement result during a monitoring period, and the monitoring period starts at the start time of the PRACH time period or a configured time point.

[0018] According to an embodiment of the first aspect of the present invention, the length of the PRACH period is equal to the length of the monitoring period plus the length of the PRACH resource.

[0019] According to an embodiment of the first aspect of the present invention, the measurement result of the PRACH period in a measurement cycle is defined as an average value of the measurement results during the activity period relative to the activity period.

[0020] According to an embodiment of the first aspect of the present invention, the measurement result of the PRACH period in a measurement cycle is defined as being within an average value of the measurement results during the activity period relative to the measurement cycle.

[0021] According to an embodiment of the first aspect of the present invention, the measurement result refers to an average value of received signal strength on the PRACH resource during the monitoring period.

[0022] According to an embodiment of the first aspect of the present invention, the length of the monitoring period is adjusted or configured according to different user equipment or different SDT services.

[0023] According to an embodiment of the first aspect of the present invention, when an SDT service occurs, the received signal strength on the PRACH resource is measured to obtain a measurement result of the PRACH resource.

[0024] According to an embodiment of the first aspect of the present invention, the method further includes: when the measurement result is less than or equal to a configured threshold, selecting the next measurement PRACH period or the next PRACH period to perform the SDT service.

[0025] According to an embodiment of the first aspect of the present invention, the method further includes: when the measurement result is less than or equal to a configured threshold, after a backoff period, selecting the next measurement PRACH period or the next PRACH period to perform the SDT service.

[0026] According to an embodiment of the first aspect of the present invention, the method further includes: when no available PRACH resources are detected within a configured number of measurements, adjusting the configured threshold.

[0027] According to an embodiment of the first aspect of the present invention, the PRACH pool is maintained in real time by the user equipment.

[0028] According to an embodiment of the first aspect of the present invention, the PRACH resources indicated by the base station as occupied are excluded from the available PRACH resources.

[0029] A second aspect of the present invention provides a user equipment, comprising a transceiver and a processor, the processor being electrically connected to the transceiver and configured to perform the following operations. The operations include: receiving a configuration indicating a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters from a base station; selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship; sending a random access preamble to the base station through the selected PRACH resource; sending a radio resource control (RRC) connection recovery request to the base station; and receiving an RRC connection release request from the base station.

[0030] According to an embodiment of the second aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resources includes: sending a first message to the base station through the selected PRACH resources, the first message carrying uplink UL user plane UP data and / or a random access preamble; and wherein the receiving of an RRC connection release request from the base station includes: receiving a second message from the base station, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0031] According to an embodiment of the second aspect of the present invention, sending an RRC connection recovery request to the base station includes: transmitting the RRC connection recovery request and / or UL UP data to the user equipment; and wherein receiving an RRC connection release request from the base station includes: receiving a second message from the base station, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0032] According to an embodiment of the second aspect of the present invention, the method also includes: after sending the random access preamble code to the base station, receiving a second message carrying a random access response RAR from the base station; wherein the sending of a wireless resource control RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including an RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0033] According to an embodiment of the second aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resources includes: sending a first message to the base station through the selected PRACH resources, the first message including a random access preamble and / or a UL UP authorization request or a scheduling report SR or a buffer status report BSR; wherein after the first message is sent to the base station through the selected PRACH resources, the method further includes: after sending the first message to the base station through the selected PRACH resources, receiving a second message carrying a random access response RAR and / or a UL authorization signal from the base station; wherein the sending of an RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including the RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or a confirmation ACK signal or a negative confirmation NACK signal.

[0034] According to an embodiment of the second aspect of the present invention, the sending of a random access preamble to the base station through the selected PRACH resources includes: sending a first message to the base station through the selected PRACH resources, the first message carrying ULUP data and / or a random access preamble; wherein after the sending of the first message to the base station through the selected PRACH resources, the method also includes: receiving a second message from the base station, the second message carrying a random access response RAR and an acknowledgment ACK signal or a negative acknowledgment NACK signal; wherein the sending of an RRC connection recovery request to the base station includes: sending a third message to the base station, the third message including the RRC connection recovery request and / or UL UP data; and wherein the receiving of an RRC connection release request from the base station includes: receiving a fourth message from the base station, the fourth message including the RRC connection release request and / or DL ​​UP data or a acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0035] According to an embodiment of the second aspect of the present invention, selecting one of the PRACH resources corresponding to the user equipment access parameters according to the mapping relationship includes: measuring the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; determining a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resources is less than or equal to a configuration threshold transmitted by the base station; and selecting one of the available PRACH resources from the PRACH pool.

[0036] According to an embodiment of the second aspect of the present invention, the received signal strength strength represents reference signal received power RSRP, reference signal received quality RSRQ, received signal strength indication RSSI and / or signal to interference plus noise ratio SINR.

[0037] According to an embodiment of the second aspect of the present invention, measuring the received signal strength on the PRACH resource to obtain the measurement result of the PRACH resource includes: measuring the received signal strength on the PRACH resource to obtain the measurement result during a monitoring period, and the monitoring period starts at the start time of the PRACH time period or a configured time point.

[0038] According to an embodiment of the second aspect of the present invention, the length of the PRACH period is equal to the length of the monitoring period plus the length of the PRACH resource.

[0039] According to an embodiment of the second aspect of the present invention, the measurement result of the PRACH period in a measurement cycle is defined as an average value of the measurement results during the activity period relative to the activity period.

[0040] According to an embodiment of the second aspect of the present invention, the measurement result of the PRACH period in a measurement cycle is defined as being within an average value of the measurement results during the activity period relative to the measurement cycle.

[0041] According to an embodiment of the second aspect of the present invention, the measurement result refers to an average value of received signal strength on the PRACH resource during the monitoring period.

[0042] According to an embodiment of the second aspect of the present invention, the length of the monitoring period is adjusted or configured according to different user equipment or different SDT services.

[0043] According to an embodiment of the second aspect of the present invention, when an SDT service occurs, the received signal strength on the PRACH resource is measured to obtain a measurement result of the PRACH resource.

[0044] According to an embodiment of the second aspect of the present invention, the operation further includes: when the measurement result is less than or equal to a configured threshold, selecting the next measurement PRACH period or the next PRACH period to perform the SDT service.

[0045] According to an embodiment of the second aspect of the present invention, the operation further includes: when the measurement result is less than or equal to a configured threshold, after a backoff period, selecting the next measurement PRACH period or the next PRACH period to perform the SDT service.

[0046] According to an embodiment of the second aspect of the present invention, the operation further includes: when no available PRACH resources are detected within a configured number of measurements, adjusting the configured threshold.

[0047] According to an embodiment of the second aspect of the present invention, the PRACH pool is maintained in real time by the user equipment.

[0048] According to an embodiment of the second aspect of the present invention, the PRACH resources indicated by the base station as occupied are excluded from the available PRACH resources.

[0049] The third aspect of the present invention provides a method for small data transmission SDT based on random access, which is executed in a base station and includes: sending a mapping relationship between multiple physical random access channel PRACH resources and multiple access parameters to a user equipment; receiving a random access preamble code from the user equipment through a selected PRACH resource, wherein the selected PRACH resource is one of the corresponding PRACH resources selected from the access parameters of the user equipment according to the mapping relationship; receiving a radio resource control RRC connection recovery request from the user equipment; and sending an RRC connection release request to the user equipment.

[0050] According to an embodiment of the third aspect of the present invention, the access parameter is a user equipment identification ID.

[0051] According to an embodiment of the third aspect of the present invention, the access parameter is an access ID.

[0052] According to an embodiment of the third aspect of the present invention, the access parameter is an access category.

[0053] According to an embodiment of the third aspect of the present invention, the access parameter is a Quality of Service (QoS) file.

[0054] According to an embodiment of the third aspect of the present invention, the access parameter indicates the priority of the multiple PRACH resources.

[0055] According to an embodiment of the third aspect of the present invention, the access parameter indicates various SDT service types.

[0056] According to an embodiment of the third aspect of the present invention, sending a mapping relationship between multiple PRACH resources and multiple access parameters to a user equipment includes: periodically broadcasting the mapping relationship between the multiple PRACH resources and the multiple access parameters to the user equipment.

[0057] According to an embodiment of the third aspect of the present invention, sending a mapping relationship between multiple PRACH resources and multiple access parameters to a user equipment includes: periodically unicasting the mapping relationship between the multiple PRACH resources and the multiple access parameters to the user equipment.

[0058] According to an embodiment of the third aspect of the present invention, the mapping relationship is modified or generated according to the network load.

[0059] According to an embodiment of the third aspect of the present invention, the mapping relationship is transmitted from the 5G core network.

[0060] According to an embodiment of the third aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment through the selected PRACH resource, the first message carrying uplink UL user plane UP data and / or a random access preamble; and wherein the sending of an RRC connection release request to the user equipment includes: sending a second message to the user equipment, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0061] According to an embodiment of the third aspect of the present invention, the receiving of the radio resource control RRC connection recovery request from the user equipment includes: receiving an RRC connection recovery request and / or uplink UL user plane UP data from the user equipment; and wherein the sending of the RRC connection release request to the user equipment includes: sending a second message to the user equipment, the second message carrying the RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0062] According to an embodiment of the third aspect of the present invention, the method also includes: after receiving the random access preamble code from the user equipment, sending a second message carrying a random access response RAR to the user equipment; wherein the receiving of the radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message including the RRC connection recovery request and / or UL UP data; and wherein the sending of the RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0063] According to an embodiment of the third aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment, the first message including a random access preamble and / or a UL UP authorization request or a scheduling report SR or a buffer status report BSR; wherein after the first message is received from the user equipment through the selected PRACH resource, the method further includes: after receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, the second message carrying a random access response RAR and / or a UL authorization signal, the first message including a random access preamble and / or a UL UP authorization request or SR or BSR; wherein the receiving of a radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and wherein the sending of an RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

[0064] According to an embodiment of the third aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment, the first message including a random access preamble and / or UL UP data; wherein after the first message is received from the user equipment through the selected PRACH resource, the first message including a random access preamble and / or UL UP data, the method further includes: after receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, the second message carrying a random access response RAR and an ACK signal or a negative ACK signal, the first message including a random access preamble and / or UL UP data; wherein the receiving of a radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and wherein the sending of an RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or a ACK signal or a negative ACK signal.

[0065] According to an embodiment of the third aspect of the present invention, the method also includes: sending a configuration threshold and a measurement configuration to the user equipment, wherein the user equipment is used to measure the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; the user equipment is used to determine a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resources is less than or equal to the configuration threshold; the user equipment is used to select one of the available PRACH resources from the PRACH pool.

[0066] A fourth aspect of the present invention provides a base station, comprising a transceiver and a processor, the processor being electrically connected to the transceiver and configured to perform the following operations. The operations include: sending a mapping relationship between multiple physical random access channel PRACH resources and multiple access parameters to a user equipment; receiving a random access preamble from the user equipment through a selected PRACH resource, wherein the selected PRACH resource is one of the corresponding PRACH resources selected from the access parameters of the user equipment according to the mapping relationship; receiving a radio resource control RRC connection recovery request from the user equipment; and sending an RRC connection release request to the user equipment.

[0067] According to an embodiment of the fourth aspect of the present invention, the access parameter is a user equipment identification ID.

[0068] According to an embodiment of the fourth aspect of the present invention, the access parameter is an access ID.

[0069] According to an embodiment of the fourth aspect of the present invention, the access parameter is an access category.

[0070] According to an embodiment of the fourth aspect of the present invention, the access parameter is a Quality of Service (QoS) file.

[0071] According to an embodiment of the fourth aspect of the present invention, the access parameter indicates the priority of the multiple PRACH resources.

[0072] According to an embodiment of the fourth aspect of the present invention, the access parameter indicates various SDT service types.

[0073] According to an embodiment of the fourth aspect of the present invention, sending a mapping relationship between multiple PRACH resources and multiple access parameters to a user equipment includes: periodically broadcasting the mapping relationship between the multiple PRACH resources and the multiple access parameters to the user equipment.

[0074] According to an embodiment of the fourth aspect of the present invention, sending a mapping relationship between multiple PRACH resources and multiple access parameters to a user equipment includes: periodically unicasting the mapping relationship between the multiple PRACH resources and the multiple access parameters to the user equipment.

[0075] According to an embodiment of the fourth aspect of the present invention, the mapping relationship is modified or generated according to the network load.

[0076] According to an embodiment of the fourth aspect of the present invention, the mapping relationship is transmitted from the 5G core network.

[0077] According to an embodiment of the fourth aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment through the selected PRACH resource, the first message carrying uplink UL user plane UP data and / or a random access preamble; and wherein the sending of an RRC connection release request to the user equipment includes: sending a second message to the user equipment, the second message carrying an RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0078] According to an embodiment of the fourth aspect of the present invention, the receiving of the radio resource control RRC connection recovery request from the user equipment includes: receiving an RRC connection recovery request and / or uplink UL user plane UP data from the user equipment; and wherein the sending of the RRC connection release request to the user equipment includes: sending a second message to the user equipment, the second message carrying the RRC connection release request and / or downlink DL user plane UP data or an acknowledgment ACK signal or a negative acknowledgment NACK signal.

[0079] According to an embodiment of the fourth aspect of the present invention, the method also includes: after receiving the random access preamble code from the user equipment, sending a second message carrying a random access response RAR to the user equipment; wherein the receiving of the radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message including the RRC connection recovery request and / or UL UP data; and wherein the sending of the RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or a confirmation ACK signal or a negative confirmation NACK signal.

[0080] According to an embodiment of the fourth aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment, the first message including a random access preamble and / or a UL UP authorization request or a scheduling report SR or a buffer status report BSR; wherein after the first message is received from the user equipment through the selected PRACH resource, the method further includes: after receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, the second message carrying a random access response RAR and / or a UL authorization signal, the first message including a random access preamble and / or a UL UP authorization request or SR or BSR; wherein the receiving of a radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and wherein the sending of an RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

[0081] According to an embodiment of the fourth aspect of the present invention, the receiving of a random access preamble from the user equipment through the selected PRACH resource includes: receiving a first message from the user equipment, the first message including a random access preamble and / or UL UP data; wherein after the first message is received from the user equipment through the selected PRACH resource, the first message including a random access preamble and / or UL UP data, the method further includes: after receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, the second message carrying a random access response RAR and an ACK signal or a negative ACK signal, the first message including a random access preamble and / or UL UP data; wherein the receiving of a radio resource control RRC connection recovery request from the user equipment includes: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and wherein the sending of an RRC connection release request to the user equipment includes: sending a fourth message to the user equipment, the fourth message including the RRC connection release request and / or DL ​​UP data or a ACK signal or a negative ACK signal.

[0082] According to an embodiment of the fourth aspect of the present invention, the operation also includes: sending a configuration threshold and a measurement configuration to the user equipment, wherein the user equipment is used to measure the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; the user equipment is used to determine a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resources is less than or equal to the configuration threshold; the user equipment is used to select one of the available PRACH resources from the PRACH pool.

[0083] The fifth aspect of the present invention provides a method for small data transmission SDT based on random access, which is executed in a base station and includes: establishing a mapping relationship between a type parameter and a backoff period length; a first user equipment having a physical random access channel PRACH resource detects the amount of data or the random access channel RACH type or the SDT type during the execution of the RACH-based SDT; according to the detected amount of data or the detected RACH type or the detected SDT type, a backoff period is selected from the mapping relationship; and information of the selected backoff period is transmitted to a second user equipment within the coverage controlled by the base station, so that the second user equipment will not perform the RACH-based SDT through the PRACH resource during the selected backoff period.

[0084] According to an embodiment of the fifth aspect of the present invention, transmitting the selected information of the backoff period to a second user equipment within the coverage controlled by the base station includes: broadcasting or unicasting the information of the backoff period to the second user equipment.

[0085] According to an embodiment of the fifth aspect of the present invention, the type parameters include data volume, service type, random access channel RACH type and SDT type.

[0086] According to an embodiment of the fifth aspect of the present invention, the data amount is indicated in a scheduling report SR or a buffer status report BSR.

[0087] According to an embodiment of the fifth aspect of the present invention, the service type is represented by an access identity ID, a category ID, and QoS related parameters.

[0088] According to an embodiment of the fifth aspect of the present invention, the RACH type includes 2-step RACH and 4-step RACH.

[0089] According to an embodiment of the fifth aspect of the present invention, the SDT type includes pre-configured grant-based SDT and RACH-based SDT, or pre-configured grant-based SDT, RACH-based 2-step SDT and RACH-based 4-step SDT.

[0090] The sixth aspect of the present invention provides a base station, which includes a transceiver and a processor, the processor is electrically connected to the transceiver and configured to perform the following operations. The operations include: establishing a mapping relationship between a type parameter and a backoff period length; a first user equipment with a physical random access channel PRACH resource detects the amount of data or the random access channel RACH type or the SDT type during the execution of a RACH-based SDT; according to the detected amount of data or the detected RACH type or the detected SDT type, a backoff period is selected from the mapping relationship; and information about the selected backoff period is transmitted to a second user equipment within the coverage controlled by the base station, so that the second user equipment will not perform a RACH-based SDT through the PRACH resource during the selected backoff period.

[0091] According to an embodiment of the sixth aspect of the present invention, transmitting the selected information of the backoff period to a second user equipment within the coverage controlled by the base station includes: broadcasting or unicasting the information of the backoff period to the second user equipment.

[0092] According to an embodiment of the sixth aspect of the present invention, the type parameters include data volume, service type, random access channel RACH type and SDT type.

[0093] According to an embodiment of the sixth aspect of the present invention, the data amount is indicated in a scheduling report SR or a buffer status report BSR.

[0094] According to an embodiment of the sixth aspect of the present invention, the service type is represented by an access identity ID, a category ID, and QoS related parameters.

[0095] According to an embodiment of the sixth aspect of the present invention, the RACH type includes 2-step RACH and 4-step RACH.

[0096] According to an embodiment of the sixth aspect of the present invention, the SDT type includes pre-configured grant-based SDT and RACH-based SDT, or pre-configured grant-based SDT, RACH-based 2-step SDT and RACH-based 4-step SDT.

[0097] The seventh aspect of the present invention provides a method for small data transmission SDT based on random access, which is executed in a base station and includes: establishing a mapping relationship between an SDT service type and an access identity ID or an access category; determining an access control configuration based on the mapping relationship, wherein the access control configuration executes the SDT service according to the access identity ID or access category set according to the network load; and sending the access control configuration to a user device that is allowed to execute the SDT service so that the user device executes RACH-based SDT.

[0098] According to an embodiment of the seventh aspect of the present invention, sending the access control configuration to the user equipment allowed to perform the SDT service includes: broadcasting the access control configuration to the user equipment allowed to perform the SDT service.

[0099] According to an embodiment of the seventh aspect of the present invention, the network load represents the number of successful / failed random accesses, the number of random access attempts, and the amount of data transmitted within a specified period.

[0100] The eighth aspect of the present invention provides a base station, comprising a transceiver and a processor, the processor being electrically connected to the transceiver and configured to perform the following operations. The operations include: establishing a mapping relationship between an SDT service type and an access identity ID or an access category; determining an access control configuration according to the mapping relationship, the access control configuration allowing the set access identity ID or access category to perform the SDT service according to the network load; and sending the access control configuration to a user equipment that is allowed to perform the SDT service, so that the user equipment performs the RACH-based SDT.

[0101] According to an embodiment of the eighth aspect of the present invention, sending the access control configuration to the user equipment allowed to perform the SDT service includes: broadcasting the access control configuration to the user equipment allowed to perform the SDT service.

[0102] According to an eighth aspect of the present invention, the network load represents the number of successful / failed random accesses, the number of random access attempts, and the amount of data transmitted within a specified period.

[0103] The method disclosed in the present invention can be implemented in a chip. The chip may include a processor configured to call and run a computer program stored in a memory so that a device equipped with the chip executes the method disclosed in the present application.

[0104] The method disclosed in the present invention can be programmed as computer-executable instructions stored in a non-transitory computer-readable medium. When the non-transitory computer-readable medium is loaded into a computer, it instructs the processor of the computer to execute the method disclosed in the present invention.

[0105] The non-transitory computer readable medium may include at least one of the following readable media: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an EPROM, an electrically erasable programmable read-only memory, and a flash memory.

[0106] The methods disclosed in the present invention may be programmed as a computer program product, which causes a computer to execute the methods disclosed in the present application.

[0107] The methods disclosed in the present invention may be programmed as computer programs, which cause a computer to execute the methods disclosed in the present application.

[0108] Beneficial Effects

[0109] The embodiment of the present invention provides a method, a base station and a user equipment for small data transmission based on random access. The present invention reduces the conflict when multiple UEs perform RACH-based small data transmission and alleviates network congestion. Restrictions between UE / SDT services and PRACH resources are introduced so that RACH-based SDT events can be dispersed in the configured PRACH resources. The present invention reduces random access conflicts initiated by different UEs on the same PRACH resource. The restriction can be a mapping between UE ID / access ID / access category / QoS profile and PRACH resources.

[0110] The PRACH resource can be selected based on the measurement result of the PRACH resource. The UE shall monitor the configured PRACH resource. If the measurement result is less than or equal to the configured threshold, the UE is considered to be available for performing RACH-based small data transmission. The UE measures the signal strength received on the configured PRACH resource. Small data transmission based on the LBT mechanism will effectively reduce conflicts between UEs.

[0111] The UE may continuously monitor PRACH resources and record / report PRACH resource status information, or perform measurements based on the discontinuous reception (DRX) mechanism for power saving considerations. In addition, the UE may perform monitoring after receiving PRACH resource configuration or entering the RRC_INACTIVE state. Alternatively, the measurement may be triggered when a small data transmission occurs, i.e., the UE starts monitoring only when a small data transmission needs to be performed. After detecting available PRACH resources and / or successfully performing a small data transmission, the UE shall stop measuring. However, the UE may be configured to perform monitoring in any of the above measurement modes.

[0112] In addition, the present invention also proposes to perform fallback when the UE cannot perform small data transmission based on random access. When random access contention occurs between UEs performing small data transmission, the base station should send fallback information to the UE that failed to perform RACH-based small data transmission or / and the UE within the coverage of the base station through unicast and / or broadcast. The length of the fallback time can be obtained by the amount of data and / or the SDT type (RACH-based SDT or pre-configured grant-based SDT) and / or the random access type (2-step random access or 4-step random access).

[0113] In addition, the present invention also proposes a mechanism based on access control, where the base station prohibits or allows certain UEs to perform small data transmission based on RACH, so that the network load can be controlled. Small data transmission services are divided into multiple access categories, and / or multiple access IDs are assigned to small data transmission services. The base station should then control the network load by prohibiting / allowing the execution of small data services with specific access IDs or belonging to specific access categories. The configuration should be dynamically adjusted according to the network load of the base station to effectively utilize radio resources. The access control configuration can be transmitted to the UE via broadcast or unicast. Or in another way, the random access procedure for small data transmission can be accepted / rejected by the base station according to the access control configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0115] Figure 1 A communication system including UE, base station and network entity equipment is described.

[0116] Figure 2A and 2B A two-step flow chart of RACH-based SDT performed by a user equipment and a base station according to an embodiment of the present invention is shown.

[0117] Figure 3A , 3B 3C and 3C are flowcharts of a RACH-based 4-step SDT performed by a user equipment and a base station according to an embodiment of the present invention.

[0118] Figure 4 A flow chart of measurement-based PRACH resource selection performed by a user equipment and a base station according to an embodiment of the present invention is shown.

[0119] Figure 5 PRACH resource pattern is shown.

[0120] Figure 6 DRX measurement cycle is shown.

[0121] Figure 7 A flow chart of determining fallback based on auxiliary information executed by a user equipment and a base station according to an embodiment of the present invention is shown.

[0122] Figure 8 A flow chart of network congestion based access control performed by a user equipment and a base station according to an embodiment of the present invention is shown.

[0123] Fig. 9 is a block diagram of a system for wireless communication according to an embodiment of the present invention. DETAILED DESCRIPTION

[0124] The embodiments of the present application describe in detail the technical matters, structural features, implementation purposes and effects with reference to the accompanying drawings. Specifically, the terms in the embodiments of the present application are only used for the purpose of describing specific embodiments, rather than limiting the disclosure.

[0125] As described in 3GPP TS22.891, the NR system should:

[0126] - Efficient and flexible, suitable for short burst data with low throughput

[0127] - Support efficient signaling mechanisms (e.g., signaling is smaller than payload)

[0128] - Generally reduces signaling overhead.

[0129] The signaling overhead from UE handling small packets in RRC_INACTIVE state is a common problem and will become a critical issue for UEs in NR. This not only affects network performance and efficiency, but also UE battery performance. Typically, devices in RRC_INACTIVE state for any intermittent small data packets will benefit from enabling small data transmission in the inactive state.

[0130] The key enablers for small data transmission in NR, namely RRC_INACTIVE state, 2-step, 4-step RACH and configured Grant Type 1, have been specified in 3GPP Release 15 and 16. Therefore, this work builds on these foundations to enable small data transmission in NR RRC_INACTIVE state.

[0131] In the revised Small Data Transfer RP-201305WID, the following scope related to Small Data Transfer is identified:

[0132] This work item enables small data transfers in the RRC_INACTIVE state as follows:

[0133] -For RRC_INACTIVE state:

[0134] o UL small data transmission, applicable to RACH-based schemes (i.e. 2-step and 4-step RACH):

[0135] ■ Generic process to enable UP data transmission for small packets in the inactive state (e.g. using MSGA or MSG3) [RAN2]

[0136] ■ Enable flexible payload size larger than Rel-16 CCCH message size, currently inactive for MSGA and MSG3, to support UP data transmission in UL (actual payload size is up to network configuration) [RAN2]

[0137] ■Context extraction and data forwarding for RACH based solutions (with or without anchor reset bit) is inactive [RAN2, RAN3]

[0138] NOTE 1: The security aspects of the above solutions should be checked using SA3

[0139] o Transmit UL data on pre-configured PUSCH resources (i.e. reuse configured grant type 1) - when TA is valid,

[0140] ■General process for small data transfers from inactive state [RAN2] over configured Grant Type 1 resources

[0141] ■Configure the configured grant type 1 resources for small data transfers in the UL inactive state [RAN2]

[0142] o Specify RRM Core requirements for small data transfers in RRC_INACTIVE units if required [RAN4]

[0143] No new RRC states should be introduced in this WID. The transmission of small data in UL, the subsequent transmission of small data in UL and DL, and the state transition decision should be under network control.

[0144] The focus of WID should be on licensed operators and the solutions could be repurposed for NR-U if applicable.

[0145] For direct data transmission in the RRC_INACTIVE state, in the event of a conflict and network congestion, a mechanism to alleviate network congestion should be considered in the design.

[0146] Related protocols about small data transmission (SDT)

[0147] 3GPP RAN2#111-e protocol

[0148] 1 Support small data transmission with RRC messages as the baseline for RA-based and CG-based schemes.

[0149] 2. No RRC can be used for limited use cases with lower priority (e.g. same service unit and / or CG).

[0150] 3. Context acquisition and data forwarding with and without anchor relocalization will be considered. The issue of “without anchor relocalization” needs further study.

[0151] 4. From RAN2 perspective, the “configuration” stored in the UE context is the RLC bearer configuration for any SDT mechanism (RACH and CG).

[0152] 5.2-step RACH or 4-step RACH is applied to RACH-based uplink small data transmission in RRC_INACTIVE state.

[0153] 6. Small uplink data can be sent as msgA of 2-step RACH or msg3 of 4-step RACH.

[0154] 7. Small data transfers are configured by the network on a per-DRB basis.

[0155] 8. The data volume threshold is used by the UE to decide whether to perform SDT. Further study is needed on how to calculate the data volume. Further study is needed on if an “additional SDT-specific” RSRP threshold is further used to determine whether the UE should perform SDT.

[0156] 9. Support UL / DL transmission after UL SDT without transitioning to RRC_CONNECTED.

[0157] 10. When the UE is in RRC_INACTIVE state, it should be possible to send multiple UL and DL packets as part of the same SDT mechanism without transitioning to RRC_CONNECTED under a dedicated grant. Further study is needed on the details and whether any network indication is required.

[0158] refer to Figure 1 As shown, the communication system includes user equipment (UE) 10a, 10b, a base station 200 and a network entity device 30. The connections between the devices and device components are shown as lines and arrows in the figure. UE 10a may include a processor 11a, a memory 12a and a transceiver 13a. UE 10b may include a processor 11b, a memory 12b and a transceiver 13b. Base station 200 may include a processor 201, a memory 202 and a transceiver 203. Network entity device 300 may include a processor 301, a memory 302 and a transceiver 303. Each processor 11a, 11b, 201 and 301 may implement the functions, processes and / or methods provided by the embodiment after execution. The wireless interface protocol layer may be implemented in the processors 11a, 11b, 201 and 301. Various programs and information may be stored in each memory 12a, 12b, 202 and 302 to cooperate with the operation of the connected processor. Each transceiver 13a, 13b, 203 and 303 is coupled to a processor for sending and / or receiving radio signals or wired signals. The base station 200 can be one of an eNB, a gNB or other types of wireless nodes, and can configure wireless resources for UEs 10a and 10b.

[0159] Each processor 11a, 11b, 201 and 301 may include an application specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. Each memory 12a, 12b, 202 and 302 may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium and / or other storage devices. Each transceiver 13a, 13b, 203 and 303 may include a baseband circuit and a radio frequency (RF) circuit to process radio frequency signals. When the embodiment is implemented in software, when the embodiment is implemented in software, the technology described herein can be implemented by executing the functional modules, processes, functions, entities, etc. described herein. The module can be stored in a memory and executed by a processor. The memory can be implemented inside or outside the processor, and various devices known in the art can be coupled to the processor.

[0160] The network entity device 300 may be a node in the CN. The CN may include an LTE CN or a 5G core network (5GC), including a user plane function (UPF), a session management function (SMF), a mobility management function (AMF), a unified data management (UDM), a policy control function (PCF), a control plane (CP) / user plane (UP) separation (CUPS), an identity authentication server (AUSF), a network slice selection function (NSSF) and a network open function (NEF).

[0161] Example 1

[0162] refer to Figure 1 , Figure 2A and Figure 2B . Figure 2A and Figure 2B Flowcharts of RACH-based 2-step SDT performed by the user equipment 10a and the base station 200 are respectively shown. According to an embodiment of the present invention, the main idea of ​​this embodiment is to introduce restrictions between the UE or SDT service and the PRACH resources so that the occurrence of RACH-based SDT is distributed in the configured PRACH resources with equal probability as much as possible.

[0163] The base station 200 sends a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters to the user equipment 10a (step 202). The access parameters include, but are not limited to, UE ID / access ID / access category / QoS related parameters (such as delay requirements, etc.) of the SDT service. The mapping relationship is a mapping relationship between the UE ID / access ID / access category / QoS related parameters (such as delay requirements, etc.) of the service and the PRACH resources, etc. RACH-based SDT occurs between non-overlapping PRACH resources in the area controlled and covered by the base station 200.

[0164] In other words, the SDT dedicated PRACH resources can be designed as multiple non-overlapping PRACH resource subsets. Each PRACH resource subset is configured for one or more UEs, that is, UE 10a is restricted to selecting PRACH resources (randomly or based on measurement results) from multiple PRACH resource subsets configured therefor. Or the mapping relationship is determined by the mapping relationship / priority between the PRACH resource subset and the service type / access ID / access category / QoS related parameters (such as latency requirements, etc.), or is set by other service-related configuration files. For the services supported by the UE, when the supported services have the same priority value or its priority value is already within the range of one or more of the above configuration files, PRACH resources can only be selected from the PRACH resource subset configured for the service to perform SDT.

[0165] The restriction may be defined in the technical specification or configured by the base station 200. The base station 200 may obtain the relevant configuration from the 5G Core and then forward it to the UE, or the base station 200 may modify / generate the restriction information according to the network load and then send it to the UEs 10a, 10b within the coverage controlled by the base station 200. The configuration information related to the restriction may be sent to the UE 10a or triggered by the base station 200 through unicast or periodic broadcast.

[0166] like Figure 2A As shown, in one embodiment, UE 10a selects one of the PRACH resources corresponding to the access parameters of user equipment 10a according to the mapping relationship, and sends a message MsgA to base station 200 through the selected PRACH resource, and the message MsgA carries the random access preamble (step 204a). Then, UE 10a sends a message carrying an RRC connection recovery request RRCResumeRequest and uplink (Uplink, UL) user plane (User, UP) data or an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal to base station 200, as shown in step 206a. Base station 200 sends a second message MsgB to user equipment 10a, and the second message MsgB carries an RRC connection release request RRCconnectionreleaserequest and downlink (Downlink, DL) user plane data or an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal (step 208a).

[0167] like Figure 2B As shown, in another embodiment, UE 10a selects one of the PRACH resources corresponding to the access parameters of user equipment 10a according to the mapping relationship, and sends a first message MsgA to base station 200 through the selected PRACH resource, the first message MsgA carrying uplink (UL) user plane (UP) data and / or random access preamble (Random access preamble) selected PRACH resource (step 204b). Base station 200 sends a second message MsgB to user equipment 10a, the second message MsgB carrying RRC connection release request RRC connection release request and downlink (DL) user plane (UP) data or confirmation (ACK) signal or negative confirmation (NACK) signal (step 208b).

[0168] See also Figure 1 and Figure 3A , Figure 3B and Figure 3C . Figure 3A , Figure 3B and Figure 3CFlow charts of the 4-step SDT based on RACH performed by the user equipment 10a and the base station 200 in the embodiment of the present invention are respectively shown. Figure 3A As shown, the base station 200 sends a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters to the user equipment 10a (step 302). In another embodiment, the UE 10a selects one of the PRACH resources corresponding to the access parameters of the user equipment 10 according to the mapping relationship, and sends a first message Msg1 to the base station 200 through the selected PRACH resource, and the first message Msg1 carries a random access preamble (step 304a). After receiving the random access preamble, the base station 200 sends a second message Msg2 to the user equipment 10a (step 306a), and the second message Msg2 carries a random access response (RAR). The UE 10a sends a third message Msg3 to the base station 200 (step 308a), and the third message Msg3 carries a radio resource control (RRC) connection recovery request and / or UL UP data. The base station 200 sends a fourth message Msg4 to the user equipment 10a (step 310a), where the fourth message Msg4 carries an RRC connection release request RRCconnectionreleaserequest and / or downlink (DL) user plane (UP) data or an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal.

[0169] like Figure 3BAs shown, in another embodiment of the present invention, the base station 200 sends a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters to the user equipment 10a (step 302). The UE 10a selects one of the PRACH resources corresponding to the access parameter of the user equipment 10a according to the mapping relationship, and sends a first message Msg1 to the base station 200 through the selected PRACH resource, and the first message Msg1 carries a random access preamble and / or an uplink (UL) user plane (UP) grant request or a scheduling report (SR) or a buffer status report (BSR) (step 304b). After receiving the random access preamble, the base station 200 sends a second message Msg2 to the user equipment 10a, and the second message Msg2 carries a random access response (RAR) and / or a UL grant signal (step 306b). UE 10a sends a third message Msg3 to base station 200, the third message Msg3 carries a radio resource control (RRC) connection recovery request and / or UL UP data (step 308b). Base station 200 sends a fourth message Msg4 to user equipment 10a (step 310b), the fourth message Msg4 carries an RRC connection release request RRCconnectionreleaserequest and / or downlink (DL) user plane (UP) data or an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal.

[0170] like Figure 3CAs shown, in another embodiment of the present invention, the base station 200 sends a mapping relationship between multiple physical random access channel (PRACH) resources and multiple access parameters to the user equipment 10a (step 302). The UE 10a selects one of the PRACH resources corresponding to the access parameter of the user equipment 10a according to the mapping relationship, and sends a first message Msg1 to the base station 200, the first message Msg1 carrying the selected PRACH resource of the uplink (UL) user plane (UP) data and / or the random access preamble (step 304c). After receiving the random access preamble, the base station 200 sends a second message Msg2 to the user equipment 10a (step 306c), the second message Msg2 carrying a random access response (RAR) and an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal. The UE 10a sends a third message Msg3 to the base station 200 (step 308c), the third message Msg3 carrying a radio resource control (RRC) connection recovery request and / or subsequent UL UP data. The base station 200 sends a fourth message Msg4 to the user equipment 10a (step 310c), where the fourth message Msg4 carries an RRC connection release request and / or downlink (DL) user plane (UP) data or an acknowledgement (ACK) signal or a negative acknowledgement (NACK) signal.

[0171] The present invention reduces conflicts when multiple UEs perform RACH-based small data transmissions and alleviates network congestion. Restrictions between UE / SDT services and PRACH resources are introduced so that RACH-based SDT events can be dispersed in the configured PRACH resources. The present invention reduces random access conflicts initiated by different UEs on the same PRACH resource.

[0172] Example 2

[0173] See also Figure 1 and Figure 4 . Figure 4 A flowchart of the method for selecting PRACH resources based on measurement performed by the user equipment 10a and the base station 200 in SDT according to an embodiment of the present invention is shown. This embodiment provides a method for selecting PRACH resources based on measurement for small data transmission. After receiving the PRACH resource configuration (step 402), the UE 10a measures the configured PRACH resources (step 404). According to the configured threshold and the measurement result, the UE 10a determines on which PRACH resources to perform RACH-based SDT. The UE 10a selects the PRACH resources whose measurement result is less than or equal to the configured threshold to perform SDT based on RACH. Figure 2A , Figure 2B , Figure 3A , Figure 3B and Figure 3C RACH-based 2 / 4 step SDT (step 410) is shown. Then, Figure 2A step 208a, or Figure 2B Step 208b, Figure 3A Step 310a, Figure 3B Step 310b, or Figure 3C As described in step 310c, the base station 200 sends an RRC connection release request to the UE 10a.

[0174] In some embodiments, selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship includes the following operations. The UE 10a measures the signal strength received on the PRACH resource to obtain a measurement result of the PRACH resource. Then the UE 10a determines a PRACH pool having at least one available PRACH resource, wherein the available PRACH resource refers to a PRACH resource whose signal strength measurement result is less than or equal to a configuration threshold sent by the base station 200. Then, the UE 10a selects one of the PRACH resources from the PRACH pool for use.

[0175] When measuring the signal strength received on the configured PRACH resources, the signal strength indicates the reference signal received power (RSRP), the reference signal received quality (RSRQ), the received signal strength indicator (RSSI), and the signal to interference plus noise ratio (SINR). The PRACH resources where strong signals can be detected mean that the UE 10a has occupied these resources to perform random access or data transmission. Not using these occupied resources to perform SDT can reduce the random access contention between UE 10a and 10b. Instead, using PRACH resources with lower measurement results to perform SDT will make it more likely to successfully perform RACH-based SDT.

[0176] The minimum PRACH resource for UE 10a to perform monitoring and measurement can be specified through the PRACH resource configuration information. Figure 5 The PRACH resource pattern shown in FIG. 1 may be a part of a PRACH Occasion. During the monitoring period T monitor Monitor PRACH resources and determine whether the PRACH period is occupied. If the measurement result is less than or equal to the configured threshold, the PRACH period is available, otherwise it is occupied.

[0177] In some embodiments, UE 10a continuously monitors and measures the configured PRACH resources. If the PRACH resources are available, that is, the measured value is less than or equal to the configured threshold, it is recorded or reported to the upper layer. If a small amount of data is to be transmitted, UE 10a selects an available PRACH period to perform SDT.

[0178] UE 10a can monitor the monitor The UE 10a may continuously monitor the measurement results, record / report available PRACH resources or record the available / occupied status of PRACH resources without suspending / terminating the measurement. In another embodiment, the UE 10a may perform measurement at the start time of the upcoming PRACH period, determine the PRACH period during the measurement monitoring period T monitor After determining whether the PRACH is available, the UE 10a then stops monitoring and waits for another upcoming PRACH period to perform measurements.

[0179] In some embodiments, considering energy saving, the measurement of PRACH resources can be designed to be based on a discontinuous reception (DRX) mechanism. UE 10a does not continuously monitor the configured PRACH resources. Figure 6 In the DRX measurement cycle shown, the configured PRACH resources are monitored and continuous reception is performed during the "active period". During the "inactive period" of the measurement cycle, the UE 10a returns to the sleep state and does not perform reception. The measurement result of the PRACH period within the measurement cycle can be defined as the average value of the measurement results during the active period. In another embodiment, the measurement result of the PRACH period within the measurement cycle can be defined as the average value of the measurement results during the measurement cycle. When the SDT service is about to occur, the UE 10a selects an available PRACH period that meets the preconfigured conditions and performs SDT.

[0180] In some embodiments, UE 10a does not monitor PRACH resources before SDT service occurs. When SDT service occurs, UE 10a performs measurements on the configured PRACH resources. If available PRACH resources are detected, that is, the measurement result is less than or equal to the configured threshold, UE 10a will select the next PRACH period to perform SDT. Or UE 10a will back off (step 408), that is, wait for the configured period, and then perform SDT in the next PRACH period. Otherwise, if the measurement result shows that there are no available PRACH resources, UE 10a may continue to perform measurements until available PRACH resources are detected, or UE 10a waits for a period of time and then performs measurements again until available PRACH resources are detected. The length of the period can be fixed / configured or a random value within a given range.

[0181] When no available PRACH resources are detected for a long time or a certain number of measurements, the configuration threshold may be adjusted.

[0182] Optionally, the UE 10a may maintain a PRACH resource pool including at least one available PRACH resource. The PRACH resource pool may be updated in real time according to the measurement result.

[0183] The available PRACH resources need to exclude the PRACH resources indicated by the broadcast information of the base station 200 .

[0184] Monitoring period T monitor The length of the monitoring period can be set according to the UE or the service, that is, different UEs / services can be configured with different monitoring periods T. monitor The measurement result can be the measurement result during the monitoring period T monitor The average value of the measurements.

[0185] The selection of PRACH resources can be based on the measurement of PRACH resources. The UE shall monitor the configured PRACH resources. If the measurement result is less than or equal to the configured threshold, the UE is considered to be available for performing RACH-based small data transmission. The UE measures the signal strength received on the configured PRACH resources. Small data transmission based on the Listen Before Talk (LBT) mechanism will effectively reduce conflicts between UEs.

[0186] Example 3

[0187] See also Figure 1 and Figure 7 . Figure 7A flowchart of determining fallback based on auxiliary information performed by user equipment 10a, 10b and base station 200 according to an embodiment of the present invention is depicted. This embodiment discloses an association between the length of the fallback period and the amount of data / service type or RACH type (2-step RACH and 4-step RACH) / SDT type. The base station 200 establishes a mapping relationship between the type parameter and the length of the fallback period (step 702). Preferably, a mapping relationship between the amount of data or RACH type / SDT type and the length of the fallback period is established. The base station 200 can detect the amount of data and / or RACH type / SDT type information during the RACH-based SDT period performed by UE 10a using PRACH resources. The base station 200 selects one of the fallback periods from the mapping relationship according to the detected amount of data or the detected RACH type or the detected SDT type, and transmits the selected fallback period information to other UEs 10b within the coverage controlled by the base station 200 in a broadcast or unicast manner (step 710). The fallback indication BI-2 is used to indicate the fallback period information. The UE 10b receiving the backoff indication BI-2 from the base station 200 shall not use the same PRACH resource (frequency domain perspective) to perform RACH-based SDT during the backoff period indicated by the backoff indication BI-2. That is, the user equipment 10b does not perform RACH-based SDT together with the PRACH resource during the selected backoff period.

[0188] The embodiment of the present invention proposes to perform fallback when the UE cannot perform small data transmission based on random access. When random access contention occurs between UE10 and 10b, the base station 200 sends back information that the RACH-based small data transmission cannot be performed to UE 10b within the control coverage of the base station 200 through unicast and / or broadcast. The length of the fallback period can be obtained by the amount of data and / or the SDT type (RACH-based SDT or pre-configured grant-based SDT) and / or the random access type (2-step random access or 4-step random access).

[0189] The data volume information can be expressed in any form, such as BSR, SR or any other variable. It can be a continuous value within a range or a fixed value with multiple discrete values.

[0190] Service types may include smartphone applications and non-smartphone applications. Smartphone applications include instant messaging services, heartbeat / activity traffic, push notifications, etc. Non-smartphone applications include traffic from wearable devices, sensors, smart meters, etc. It can be represented by access ID, category ID, QoS related parameters, etc.

[0191] The RACH type may include 2-step RACH and 4-step RACH. The SDT type may be pre-configured grant-based SDT and RACH-based SDT, or pre-configured grant-based SDT, RACH-based 2-step SDT, and RACH-based 4-step SDT.

[0192] The fallback indication may be a continuous value within a range, or may be a plurality of discrete fixed values, or it may be expressed as several levels, such as three levels of low, medium and high, or multiple levels such as level 1, level 2, level 3 ... level N.

[0193] A data volume value or a range of volume values ​​can be mapped to a fallback value. Alternatively, multiple data volume values ​​can be mapped to a fallback value. And vice versa.

[0194] One RACH type / SDT type can be mapped to one fallback value, or multiple RACH types / SDT types can be mapped to one fallback value, or vice versa.

[0195] The service type and value of the fallback indication can be a one-to-one mapping, a many-to-one mapping, a one-to-many mapping, or a many-to-many mapping. No specific restrictions are specified here.

[0196] The fallback indication may be broadcast to the UE in system information. Or it may be transmitted to the UE via unicast, such as a RAR message.

[0197] Example 4

[0198] See also Figure 1 and Figure 8 . Figure 8 A flowchart of a network (NW) congestion based on access control performed by a user equipment 10a and a base station 200 according to an embodiment of the present invention is depicted. This embodiment discloses that small data transmission services of different services can be mapped to access IDs and / or access categories, and the different services can be heartbeat services, one-time services, etc. That is, different access IDs can be assigned to different small data transmission services. The base station 200 establishes a mapping relationship between a small data transmission (SDT) service type and an access identity (ID) or access category. Small data transmission services can be mapped to different access categories. Allocation and mapping can be based on service type, traffic pattern, QoS (e.g., priority, delay requirements, etc.) or other related profiles. The base station 200 determines an access control configuration based on the mapping relationship, and the access control configuration sets which access identities (IDs) or access categories are allowed to perform SDT services according to the network (network, NW) load. The base station 200 sends the access control configuration to the user equipment 10a, and the user equipment 10a is allowed to perform the SDT service, so that the user equipment 10a performs RACH-based SDT.

[0199] The base station 200 dynamically prohibits or allows the UE 10a from supporting services with one or more specific access IDs / access categories to perform SDT based on network load or according to configuration. The configuration of the access ID / access category for prohibiting or allowing the execution of SDT can be transmitted to the UE through system information broadcast by the base station 200. Or in another way, the base station 200 accepts or rejects random access of the SDT service with one or more specified access IDs / access categories according to the configuration.

[0200] The association between the access ID / access category and the service or related QoS may be specified by a technical specification, or may be determined by a configuration received by the base station 200 from the network entity device 300 (e.g., 5GC), or may be specified or dynamically adjusted by the base station 200.

[0201] The network load may be a successful / failed random access count, a random access attempt count, a transmitted data volume, etc. During a specified period, the base station 200 / network entity device 300 may dynamically adjust the access control configuration according to the network load.

[0202] Fig. 9 7 is a block diagram of an example system 700 for wireless communication according to an embodiment of the present application. The embodiments of the present application may use any appropriately configured hardware and / or software for implementation into the system 700. The system 700 includes a radio frequency (RF) circuit 710, a baseband circuit 720, a processing unit 730, a memory 740, a display 750, a camera 760, a sensor 770, and an input / output (I / O) interface 780.

[0203] The processing unit 730 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors, such as a graphics processor and an application processor. The processor may be coupled to a memory / storage and configured to execute instructions stored in the memory / storage to enable various applications and / or operating systems running on the system.

[0204] The baseband circuit 720 may include circuits, such as but not limited to one or more single-core or multi-core processors. The processor may include a baseband processor. The baseband circuit may handle various radio control functions, which may communicate with one or more radio networks through RF circuits. The radio control functions may include but are not limited to signal modulation, encoding, decoding, radio frequency conversion, etc. In some embodiments, the baseband circuit may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit may support communications with 5G NR, LTE, Evolved Universal Terrestrial Radio Access Network (EUTRAN) and / or other wireless metropolitan area networks (WMAN), wireless local area networks (WLAN), wireless personal area networks (WPAN). An embodiment in which the baseband circuit is configured to support radio communications of more than one wireless protocol may be referred to as a multimode baseband circuit. In different embodiments, the baseband circuit 720 may include circuits that operate with signals of baseband frequencies. For example, in some embodiments, the baseband circuit may include circuits that work with signals having an intermediate frequency, which is between the baseband frequency and the radio frequency.

[0205] RF circuitry 710 may communicate with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate communication with the wireless network. In various embodiments, the RF circuitry 710 may include circuitry that operates using signals that are not strictly considered to be radio frequencies. For example, in some embodiments, the RF circuitry may include circuitry that operates with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

[0206] In different embodiments, the transmitter circuits, control circuits, or receiver circuits discussed above regarding the UE, eNB, or gNB may be embodied in whole or in part in one or more RF circuits, baseband circuits, and / or processing units. As used herein, a "circuit" may be a portion of an application-specific integrated circuit (ASIC), an electronic circuit, a processor, and / or a memory that executes one or more software or firmware programs, a combination of logic circuits, and / or other suitable hardware components that provide the functionality. In some embodiments, an electronic device circuit may be implemented in one or more software or firmware modules, or the functionality associated with the circuit may be implemented by one or more software or firmware modules. In some embodiments, some or all of the constituent components of the baseband circuit, processing unit, and / or memory / storage may be implemented together on a system on a chip (SOC).

[0207] The memory 740 can be used to load and store data and / or instructions, such as for the system. The memory for one embodiment can include any combination of suitable volatile memory, such as dynamic random access memory (DRAM)) and / or non-volatile memory (such as flash memory). In different embodiments, the I / O interface 780 can include one or more user interfaces designed to enable a user to interact with the system and / or a peripheral component interface designed to interact with the peripheral components of the system. The user interface can include, but is not limited to, a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. The peripheral component interface can include, but is not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power interface.

[0208] In various embodiments, the sensor 770 may include one or more sensing devices to determine environmental conditions and / or location information associated with the system. In some embodiments, the sensor may include, but is not limited to, a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of or interact with a baseband circuit and / or an RF circuit to communicate with components of a positioning network, such as a global positioning system (GPS) satellite. In various embodiments, the display 750 may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system 700 may be a mobile computing device, such as, but not limited to, a laptop computing device, a tablet computing device, a smart phone, etc. In various embodiments, the system may have more or less components, and / or different architectures. Where appropriate, the methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-temporary storage medium.

[0209] The embodiments of the present application are a combination of techniques / processes that can be adopted in the 3GPP specifications to create a final product.

[0210] It is understood by those skilled in the art that each unit, algorithm and step described and disclosed in the embodiments of the present application is implemented using software or a combination of software for computers and electronic hardware. Whether the function is run in hardware or software depends on the application conditions and design requirements of the technical plan. A person of ordinary skill in the art can use different ways to implement the functions of each specific application, and such implementation should not exceed the scope of the present application. It is understood by those skilled in the art that since the working processes of the above-mentioned systems, devices and units are basically the same, he / she can refer to the working processes of the systems, devices and units in the above-mentioned embodiments. For ease of description and simplicity, these workflows will not be described in detail.

[0211] It is understood that the systems, devices and methods disclosed in the embodiments of the present application can be implemented in other ways. The above embodiments are exemplary only. The division of units is based only on logical functions, while other divisions exist in the implementation. Multiple units or components can be combined or integrated into another system. Certain features may also be omitted or skipped. On the other hand, the mutual coupling, direct coupling or communication coupling shown or discussed can be operated indirectly or in a communication manner through certain ports, devices or units through electrical, mechanical or other forms.

[0212] The units used as separate components for explanation may or may not be physically separated. The units used for display may or may not be physical units, i.e., located in one place or distributed over multiple network units. Some or all of the units are used according to the purpose of the embodiment. Moreover, each functional unit in each embodiment may be integrated into one processing unit, physically independent, or integrated into one processing unit having two or more units.

[0213] If the software functional unit is implemented and used and sold as a product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution proposed in the present application can be substantially or partially implemented in the form of a software product. Alternatively, a part of the technical plan that is beneficial to conventional technology can be implemented in the form of a software product. The software product in the computer is stored in a storage medium, including multiple commands for running a computing device (such as a personal computer, a server, or a network device) of all or part of the steps disclosed in the embodiments of the present application. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk, or other types of media capable of storing program code.

[0214] The embodiment of the present invention provides a method, a base station and a user equipment for small data transmission based on random access. In the first aspect of the present invention, the mapping relationship between UE ID / service type / QoS profile / access ID / access category and PRACH resource / PRACH period is disclosed. In the second aspect of the present invention, a measurement-based PRACH resource selection mechanism is introduced so that the UE performs RACH-based small data transmission through available PRACH resources. The third aspect of the present invention introduces the mapping relationship between data volume / SDT type / RACH type and fallback period. The base station determines the fallback period according to the data volume / SDT type / RACH type, and then successfully performs random access and transmits the fallback configuration to the UE through unicast and / or broadcast. Then, the UE performs RACH-based SDT using the same PRACH resource (in the frequency domain perspective) according to the configuration. In the fourth aspect of the present invention, an access ID is allocated to a small data service, and / or the small data transmission service is divided into several categories. In order to strengthen the access control mechanism, the present invention allows / prohibits specific UE / services from performing RACH-based SDT according to the configuration based on the access ID / access category. These adjustments are based on the network load to alleviate network congestion.

[0215] In the embodiments of the present application, specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for small data transmission (SDT) based on random access, the method being executed in a user equipment, characterized in that: include: receiving, from a base station, a configuration indicating a mapping relationship between a plurality of physical random access channel (PRACH) resources and a plurality of access parameters; Select one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship; perform random access small data transmission with the base station according to the selected PRACH resource and Sending a random access preamble to the base station via the selected PRACH resource; Sending a radio resource control (RRC) connection recovery request to the base station; as well as An RRC connection release request is received from the base station.

2. The method according to claim 1, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message carries uplink UL user plane UP data and / or a random access preamble; and The receiving of an RRC connection release request from the base station comprises: A second message is received from the base station, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an acknowledgement ACK signal or a negative acknowledgement NACK signal.

3. The method according to claim 1, characterized in that: The sending the RRC connection recovery request to the base station comprises: transmitting the RRC connection resumption request and / or UL UP data to the user equipment; and The receiving of an RRC connection release request from the base station comprises: A second message is received from the base station, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an acknowledgement ACK signal or a negative acknowledgement NACK signal.

4. The method according to claim 1, characterized in that The method further comprises: After sending the random access preamble to the base station, receiving a second message carrying a random access response RAR from the base station; The sending of a radio resource control (RRC) connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes an RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

5. The method according to claim 1, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message includes a random access preamble and / or a UL UP grant request or a scheduling report SR or a buffer status report BSR; After sending the first message to the base station through the selected PRACH resource, the method further includes: After sending the first message to the base station through the selected PRACH resource, receiving a second message carrying a random access response RAR and / or a UL grant signal from the base station; The sending of the RRC connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes the RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

6. The method according to claim 1, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message carries UL UP data and / or a random access preamble; After sending the first message to the base station through the selected PRACH resource, the method further includes: receiving a second message from the base station, where the second message carries a random access response RAR and an ACK signal or a negative ACK signal; The sending of the RRC connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes the RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

7. The method according to claim 1, characterized in that The selecting, according to the mapping relationship, one of the PRACH resources corresponding to the user equipment access parameter includes: Measuring a received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; determining a PRACH pool having available PRACH resources, wherein a measurement result of the available PRACH resources is less than or equal to a configured threshold transmitted by the base station; and One of the available PRACH resources is selected from the PRACH pool.

8. The method according to claim 7, characterized in that The received signal strength indicates a reference signal received power RSRP, a reference signal received quality RSRQ, a received signal strength indicator RSSI and / or a signal to interference plus noise ratio SINR.

9. The method according to claim 7, characterized in that: The measuring the received signal strength on the PRACH resource to obtain the measurement result of the PRACH resource includes: The received signal strength on the PRACH resource is measured to obtain a measurement result during a monitoring period, where the monitoring period starts at the start time of the PRACH period or a configured time point.

10. The method according to claim 9, characterized in that The length of the PRACH period is equal to the length of the monitoring period plus the length of the PRACH resource.

11. The method according to claim 9, characterized in that The measurement result of the PRACH period in a measurement cycle is defined as the average value of the measurement results during the activity period relative to the activity period.

12. The method according to claim 9, characterized in that The measurement result of the PRACH period in a measurement cycle is defined as the average value of the measurement results during the activity period relative to the measurement cycle.

13. The method according to claim 9, characterized in that The measurement result refers to an average value of received signal strength on the PRACH resource during the monitoring period.

14. The method according to claim 9, characterized in that The length of the monitoring period is adjusted or configured according to different user equipment or different SDT services.

15. The method according to claim 9, characterized in that When the SDT service occurs, the received signal strength on the PRACH resource is measured to obtain a measurement result of the PRACH resource.

16. The method according to claim 15, characterized in that The method further comprises: When the measurement result is less than or equal to the configured threshold, a next measurement PRACH period or a next PRACH period is selected to perform the SDT service.

17. The method according to claim 15, characterized in that The method further comprises: When the measurement result is less than or equal to the configured threshold, after the backoff period, the next measurement PRACH period or the next PRACH period is selected to perform the SDT service.

18. The method according to claim 7, characterized in that The method further comprises: If no available PRACH resources are detected within the configured number of measurements, the configured threshold is adjusted.

19. The method according to claim 7, characterized in that The PRACH pool is maintained in real time by the user equipment.

20. The method according to claim 16, characterized in that The PRACH resources indicated by the base station as occupied are excluded from the available PRACH resources.

21. A user equipment, comprising: Transceiver; and A processor is electrically connected to the transceiver and configured to perform the following operations, wherein the operations include: Receiving a configuration indicating a mapping relationship between a plurality of physical random access channel (PRACH) resources and a plurality of access parameters from a base station; performing a random access small data transmission with the base station according to the selected PRACH resource and selecting one of the PRACH resources corresponding to the user equipment access parameter according to the mapping relationship; Sending a random access preamble to the base station via the selected PRACH resource; Sending a radio resource control (RRC) connection recovery request to the base station; and An RRC connection release request is received from the base station.

22. The user equipment according to claim 21, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message carries uplink UL user plane UP data and / or a random access preamble; and The receiving of an RRC connection release request from the base station comprises: A second message is received from the base station, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an acknowledgement ACK signal or a negative acknowledgement NACK signal.

23. The user equipment according to claim 21, characterized in that The sending the RRC connection recovery request to the base station comprises: transmitting the RRC connection resumption request and / or UL UP data to the user equipment; and The receiving of an RRC connection release request from the base station comprises: A second message is received from the base station, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an acknowledgement ACK signal or a negative acknowledgement NACK signal.

24. The user equipment according to claim 21, characterized in that The operations also include: After sending the random access preamble to the base station, receiving a second message carrying a random access response RAR from the base station; The sending of a radio resource control (RRC) connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes an RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

25. The user equipment according to claim 21, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message includes a random access preamble and / or a UL UP grant request or a scheduling report SR or a buffer status report BSR; After sending the first message to the base station through the selected PRACH resource, the operation further includes: After sending the first message to the base station through the selected PRACH resource, receiving a second message carrying a random access response RAR and / or a UL grant signal from the base station; The sending of the RRC connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes the RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

26. The user equipment according to claim 21, characterized in that The sending a random access preamble code to the base station through the selected PRACH resource comprises: Sending a first message to the base station through the selected PRACH resource, where the first message carries UL UP data and / or a random access preamble; After sending the first message to the base station through the selected PRACH resource, the operation further includes: receiving a second message from the base station, where the second message carries a random access response RAR and an ACK signal or a negative ACK signal; The sending of the RRC connection recovery request to the base station comprises: sending a third message to the base station, where the third message includes the RRC connection recovery request and / or UL UP data; and The receiving of an RRC connection release request from the base station comprises: A fourth message is received from the base station, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

27. The user equipment according to claim 21, characterized in that The selecting, according to the mapping relationship, one of the PRACH resources corresponding to the user equipment access parameter includes: Measuring a received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; determining a PRACH pool having available PRACH resources, wherein a measurement result of the available PRACH resources is less than or equal to a configured threshold transmitted by the base station; and One of the available PRACH resources is selected from the PRACH pool.

28. The user equipment according to claim 27, characterized in that The received signal strength indicates a reference signal received power RSRP, a reference signal received quality RSRQ, a received signal strength indicator RSSI and / or a signal to interference plus noise ratio SINR.

29. The user equipment according to claim 27, characterized in that The measuring the received signal strength on the PRACH resource to obtain the measurement result of the PRACH resource includes: The received signal strength on the PRACH resource is measured to obtain a measurement result during a monitoring period, where the monitoring period starts at the start time of the PRACH period or a configured time point.

30. The user equipment according to claim 29, characterized in that The length of the PRACH period is equal to the length of the monitoring period plus the length of the PRACH resource.

31. The user equipment according to claim 29, characterized in that The measurement result of the PRACH period in a measurement cycle is defined as the average value of the measurement results during the activity period relative to the activity period.

32. The user equipment according to claim 29, characterized in that The measurement result of the PRACH period in a measurement cycle is defined as the average value of the measurement results during the activity period relative to the measurement cycle.

33. The user equipment according to claim 29, characterized in that The measurement result refers to an average value of received signal strength on the PRACH resource during the monitoring period.

34. The user equipment according to claim 29, characterized in that The length of the monitoring period is adjusted or configured according to different user equipment or different SDT services.

35. The user equipment according to claim 29, characterized in that When the SDT service occurs, the received signal strength on the PRACH resource is measured to obtain a measurement result of the PRACH resource.

36. The user equipment according to claim 35, characterized in that The operations also include: When the measurement result is less than or equal to the configured threshold, a next measurement PRACH period or a next PRACH period is selected to perform the SDT service.

37. The user equipment according to claim 35, characterized in that The operations also include: When the measurement result is less than or equal to the configured threshold, after the backoff period, the next measurement PRACH period or the next PRACH period is selected to perform the SDT service.

38. The user equipment according to claim 27, characterized in that The operations also include: When no available PRACH resources are detected within the configured number of measurements, the configured threshold is adjusted.

39. The user equipment according to claim 27, characterized in that The PRACH pool is maintained in real time by the user equipment.

40. The user equipment according to claim 36, characterized in that The PRACH resources indicated by the base station as occupied are excluded from the available PRACH resources.

41. A method for small data transmission (SDT) based on random access, the method being executed in a base station, characterized in that: include: Sending a mapping relationship between multiple physical random access channel PRACH resources and multiple access parameters to a user equipment; performing random access small data transmission with the user equipment according to the selected PRACH resource and Receiving a random access preamble from the user equipment through a selected PRACH resource, wherein the selected PRACH resource is one of the corresponding PRACH resources selected by the user equipment from the access parameters of the user equipment according to the mapping relationship; Receiving a radio resource control (RRC) connection recovery request from the user equipment; as well as Sending an RRC connection release request to the user equipment.

42. The method according to claim 41, characterized in that The access parameter is a user equipment identification ID.

43. The method according to claim 41, characterized in that The access parameter is an access ID.

44. The method according to claim 41, characterized in that The access parameter is an access category.

45. The method according to claim 41, characterized in that The access parameter is a quality of service QoS file.

46. ​​The method according to claim 41, characterized in that The access parameter indicates priorities of the multiple PRACH resources.

47. The method according to claim 41, characterized in that The access parameters indicate various SDT service types.

48. The method according to claim 41, characterized in that The sending of a mapping relationship between multiple PRACH resources and multiple access parameters to the user equipment includes: The mapping relationship between the multiple PRACH resources and the multiple access parameters is broadcasted to the user equipment periodically.

49. The method according to claim 41, characterized in that The sending of a mapping relationship between multiple PRACH resources and multiple access parameters to the user equipment includes: The mapping relationship between the multiple PRACH resources and the multiple access parameters is periodically unicasted to the user equipment.

50. The method according to claim 41, characterized in that The mapping relationship is modified or generated according to the network load.

51. The method according to claim 41, characterized in that The mapping relationship is transmitted from the 5G core network.

52. The method according to claim 41, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment through the selected PRACH resource, wherein the first message carries uplink UL user plane UP data and / or a random access preamble; and The sending of the RRC connection release request to the user equipment comprises: A second message is sent to the user equipment, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an ACK signal or a negative ACK signal.

53. The method according to claim 41, characterized in that The receiving a radio resource control RRC connection recovery request from the user equipment comprises: receiving an RRC connection resumption request and / or uplink UL user plane UP data from the user equipment; and The sending of the RRC connection release request to the user equipment comprises: A second message is sent to the user equipment, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an ACK signal or a negative ACK signal.

54. The method according to claim 41, characterized in that The method further comprises: After receiving the random access preamble from the user equipment, sending a second message carrying a random access response RAR to the user equipment; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message including an RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

55. The method according to claim 41, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment, where the first message includes a random access preamble and / or a UL UP grant request or a scheduling report SR or a buffer status report BSR; After receiving the first message from the user equipment through the selected PRACH resource, the method further includes: After receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, where the second message carries a random access response RAR and / or a UL authorization signal, and the first message includes a random access preamble and / or a UL UP authorization request or SR or BSR; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

56. The method according to claim 41, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment, wherein the first message includes a random access preamble and / or UL UP data; After receiving a first message from the user equipment through the selected PRACH resource, wherein the first message includes a random access preamble and / or UL UP data, the method further includes: After receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, where the second message carries a random access response RAR and an ACK signal or a negative ACK signal, and the first message includes a random access preamble code and / or UL UP data; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

57. The method according to claim 41, characterized in that Also includes: A configuration threshold and a measurement configuration are sent to the user equipment, wherein the user equipment is used to measure the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; the user equipment is used to determine a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resources is less than or equal to the configuration threshold; and the user equipment is used to select one of the available PRACH resources from the PRACH pool.

58. A base station, comprising: Transceiver; and A processor is electrically connected to the transceiver and configured to perform the following operations, wherein the operations include: Sending a mapping relationship between multiple physical random access channel PRACH resources and multiple access parameters to a user equipment; performing random access small data transmission with the user equipment according to the selected PRACH resource and Receiving a random access preamble from the user equipment through a selected PRACH resource, wherein the selected PRACH resource is one of the corresponding PRACH resources selected by the user equipment from the access parameters of the user equipment according to the mapping relationship; Receiving a radio resource control (RRC) connection recovery request from the user equipment; Sending an RRC connection release request to the user equipment.

59. The base station according to claim 58, characterized in that The access parameter is a user equipment identification ID.

60. The base station according to claim 58, characterized in that The access parameter is an access ID.

61. The base station according to claim 58, characterized in that The access parameter is an access category.

62. The base station according to claim 58, characterized in that The access parameter is a quality of service QoS file.

63. The base station according to claim 58, characterized in that The access parameter indicates priorities of the multiple PRACH resources.

64. The base station according to claim 58, characterized in that The access parameters indicate various SDT service types.

65. The base station according to claim 58, characterized in that The sending of a mapping relationship between multiple PRACH resources and multiple access parameters to the user equipment includes: The mapping relationship between the multiple PRACH resources and the multiple access parameters is broadcasted to the user equipment periodically.

66. The base station according to claim 58, characterized in that The sending of a mapping relationship between multiple PRACH resources and multiple access parameters to the user equipment includes: The mapping relationship between the multiple PRACH resources and the multiple access parameters is periodically unicasted to the user equipment.

67. The base station according to claim 58, characterized in that The mapping relationship is modified or generated according to the network load.

68. The base station according to claim 58, characterized in that The mapping relationship is transmitted from the 5G core network.

69. The base station according to claim 58, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment through the selected PRACH resource, wherein the first message carries uplink UL user plane UP data and / or a random access preamble; and The sending of the RRC connection release request to the user equipment comprises: A second message is sent to the user equipment, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an ACK signal or a negative ACK signal.

70. The base station according to claim 58, characterized in that The receiving a radio resource control RRC connection recovery request from the user equipment comprises: receiving an RRC connection resumption request and / or uplink UL user plane UP data from the user equipment; and The sending of the RRC connection release request to the user equipment comprises: A second message is sent to the user equipment, where the second message carries an RRC connection release request and / or downlink DL user plane UP data or an ACK signal or a negative ACK signal.

71. The base station according to claim 58, characterized in that The operations also include: After receiving the random access preamble from the user equipment, sending a second message carrying a random access response RAR to the user equipment; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message including an RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

72. The base station according to claim 58, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment, where the first message includes a random access preamble and / or a UL UP grant request or a scheduling report SR or a buffer status report BSR; After receiving the first message from the user equipment through the selected PRACH resource, the operation further includes: After receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, where the second message carries a random access response RAR and / or a UL authorization signal, and the first message includes a random access preamble and / or a UL UP authorization request or SR or BSR; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

73. The base station according to claim 58, characterized in that The receiving a random access preamble from the user equipment through the selected PRACH resource comprises: receiving a first message from the user equipment, wherein the first message includes a random access preamble and / or UL UP data; After receiving a first message from the user equipment through the selected PRACH resource, wherein the first message includes a random access preamble and / or UL UP data, the operation further includes: After receiving the first message from the user equipment through the selected PRACH resource, sending a second message to the user equipment, where the second message carries a random access response RAR and an ACK signal or a negative ACK signal, and the first message includes a random access preamble code and / or UL UP data; The receiving of a radio resource control (RRC) connection recovery request from the user equipment comprises: receiving a third message from the user equipment, the third message carrying the RRC connection recovery request and / or UL UP data; and The sending of the RRC connection release request to the user equipment comprises: A fourth message is sent to the user equipment, where the fourth message includes the RRC connection release request and / or DL ​​UP data or an ACK signal or a NACK signal.

74. The base station according to claim 58, characterized in that The operations also include: A configuration threshold and a measurement configuration are sent to the user equipment, wherein the user equipment is used to measure the received signal strength on the PRACH resource to obtain a measurement result of the PRACH resource; the user equipment is used to determine a PRACH pool with available PRACH resources, wherein the measurement result of the available PRACH resources is less than or equal to the configuration threshold; and the user equipment is used to select one of the available PRACH resources from the PRACH pool.

75. A chip, comprising: A processor configured to call and run a computer program stored in a memory so that a device equipped with the chip executes the method according to any one of claims 1 to 20.

76. A chip, comprising: A processor configured to call and run a computer program stored in a memory so that a device on which the chip is mounted executes the method according to any one of claims 41 to 57.

77. A computer-readable storage medium having a computer program stored therein, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 20.

78. A computer-readable storage medium having a computer program stored therein, wherein the computer program causes a computer to execute the method of any one of claims 41 to 57.

79. A computer program product comprising a computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 20.

80. A computer program product comprising a computer program, wherein the computer program causes a computer to execute the method of any one of claims 41 to 57.

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