CN112512080A

CN112512080A - Flow control method, device, equipment and storage medium, link state notification method, device and equipment

Info

Publication number: CN112512080A
Application number: CN202011140983.0A
Authority: CN
Inventors: 汪梦珍; 陈琳; 曲淼
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2021-03-16

Abstract

The application provides a method, a device, equipment and a storage medium for flow control and link state notification, which comprises the following steps: the first node sends the congestion information of the exit link to the second node; the congestion information is used to instruct the second node to perform data transmission, and the egress link is a link through which the first node transmits data to the third node.

Description

Flow control method, device, equipment and storage medium, link state notification method, device and equipment

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method, an apparatus, a device, and a storage medium for traffic control and link status notification.

Background

For a relay device (relay UE) node, link congestion or data cache overload may occur, and if there is no effective flow control or congestion relief scheme, and congestion relief is not performed in time, it may further cause a reduction in system transmission efficiency or a failure of a wireless link.

Disclosure of Invention

The application provides a method, a device, equipment and a storage medium for flow control and link state notification, so as to improve the transmission efficiency of a system and avoid congestion.

In a first aspect, an embodiment of the present application provides a flow control method, where the method is applied to a first node, and includes:

sending egress link congestion information to the second node;

the congestion information is used to instruct the second node to perform data transmission, and the egress link is a link through which the first node transmits data to the third node.

In a second aspect, an embodiment of the present application provides a traffic control method, where the method is applied to a second node, and includes:

receiving exit link congestion information sent by a first node;

In a third aspect, an embodiment of the present application provides a link status notification method, where the method is applied to a first node, and includes:

detecting a state of a wireless link with a second node;

transmitting the wireless link status to a third node.

In a fourth aspect, an embodiment of the present application provides a flow control device, where the flow control device is configured at a first node, and the flow control device includes:

a first sending module configured to send egress link congestion information to a second node;

In a fifth aspect, an embodiment of the present application provides a flow control device, where the flow control device is configured at a second node, and the flow control device includes:

a receiving module configured to receive egress link congestion information sent by a first node;

In a sixth aspect, an embodiment of the present application provides a link status notification apparatus, where the apparatus is configured at a first node, and includes:

a detection module configured to detect a status of a wireless link with a second node;

a second transmitting module configured to transmit the wireless link status to a third node.

In a seventh aspect, an embodiment of the present application provides an apparatus, including:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement the method as any one of the embodiments provides herein.

In an eighth aspect, the present application provides a storage medium storing a computer program, which when executed by a processor implements the method according to any one of the methods provided in the embodiments of the present application.

The method, the device, the equipment and the storage medium for flow control and link state notification provided by the embodiment of the application send the congestion information of the outlet link to the second node through the first node; the congestion information is used for indicating the second node to transmit data, and the exit link is a link for the first node to transmit data to the third node, so that the system transmission efficiency is improved, and the radio link failure is avoided.

With regard to the above embodiments and other aspects of the present application and implementations thereof, further description is provided in the accompanying drawings description, detailed description and claims.

Drawings

Fig. 1 is a schematic diagram of a sidelink relay communication application scenario provided in an embodiment of the present application;

fig. 2 is a flowchart of a flow control method according to an embodiment of the present application;

fig. 3 is a flowchart of a flow control method according to an embodiment of the present application;

fig. 4 is a flowchart of a link status notification method according to an embodiment of the present application;

fig. 5 is a schematic diagram of uplink flow control according to an embodiment of the present application;

fig. 6 is a schematic diagram of downlink flow control according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a flow control provided by an embodiment of the present application;

FIG. 8 is a schematic diagram of a PC5 RLF provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of a Uu RLF provided by an embodiment of the present application;

fig. 10 is a block diagram illustrating a flow control device according to an embodiment of the present disclosure;

fig. 11 is a block diagram illustrating a flow control device according to an embodiment of the present disclosure;

fig. 12 is a block diagram illustrating a structure of a link status notification apparatus according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of an apparatus provided in an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.

With the development of wireless multimedia services, the demand for high data rates and user experience is increasing, and thus higher requirements are placed on the system capacity and coverage of the conventional cellular network. On the other hand, application scenarios such as public safety, social networking, close-range data sharing, local advertising and the like have increased the need for people to know and communicate with nearby people or things (Proximity Services). Conventional base station-centric cellular networks have significant limitations in terms of high data rates and support for proximity services, and Device-to-Device communication technologies have evolved against this demand. The application of the D2D technology can reduce the burden of the cellular network, reduce the battery power consumption of the user equipment, increase the data rate, and improve the robustness of the network infrastructure, and well meet the requirements of the high data rate service and the proximity service. D2D technology is also known as Proximity Services (ProSe), single edge/Sidelink/link through (SL) communication; the device-to-device interface is a PC5 interface.

To support a wider range of applications and services, sidelink-based relay (relay) communication can extend coverage and improve power consumption, as applied to indoor relay communication, smart farming, smart factories, public security, etc. sidelink relay communication mainly has the following two application scenarios:

1) UE-to-Network relay: UE relay transmission in weak/no-coverage areas, such as mode 1 in fig. 1, allowing a UE1 with poor signal quality or no coverage to communicate with the network through a UE2 with network coverage nearby can help operators to extend coverage and improve capacity; wherein the UE2 is called UE-to-Network relay and the UE1 is called remote UE.

2) UE-to-UE relay: in case of earthquake or emergency, the cellular network cannot work normally or in order to extend the sidelink communication range, the devices are allowed to communicate with each other through the relay UE, as in mode 2 of fig. 1, data communication is performed between the UE3 and the UE4 through the UE5 or the multi-hop relay UE; where the UE5 is referred to as a UE-to-UE relay.

The technical scheme of the application can be applied to various communication systems, such as: a Global System for Mobile communications (GSM) System, a Code Division Multiple Access (CDMA) System, a Wideband Code Division Multiple Access (WCDMA) System, a General Packet Radio Service (GPRS), a Long Term Evolution (Long Term Evolution, LTE) System, a LIE-a (Advanced Long Term Evolution) System, a Universal Mobile Telecommunications System (UMTS), and a fifth generation Mobile communications (5th generation wireless systems, 5G) System, and the like, but the embodiments of the present invention are not limited thereto. In the present application, a 5G system is described as an example.

In the embodiment of the present application, the base station may be a device capable of communicating with the user terminal. The base station may be any device having a wireless transceiving function. Including but not limited to: a base station NodeB, an evolved node b, a base station in a 5G communication system, a base station in a future communication system, an access node in a WiFi system, a wireless relay UE, a wireless backhaul node, etc. The base station may also be a wireless controller in a Cloud Radio Access Network (CRAN) scenario; the base station may also be a small station, a transmission node (TRP), and the like, and the embodiment of the present application is not limited. In the present application, a 5G base station is described as an example.

In the embodiment of the application, the user terminal is a device with a wireless transceiving function, and can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The user terminal may be a mobile phone (mobile phone), a tablet computer (Pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal, an Augmented Reality (AR) terminal, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned driving (self driving), a wireless terminal in remote medical treatment (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), and the like. The embodiments of the present application do not limit the application scenarios. A user terminal may also be referred to as a terminal, access terminal, UE unit, UE station, mobile station, remote terminal, mobile device, UE terminal, wireless communication device, UE agent, or UE device, among others. The embodiments of the present application are not limited.

Two Sidelink link relay technical schemes based on an IP Layer (Layer 3) and an access Layer (Layer 2) are provided in 3 GPP. Wherein, the layer 3(IP layer) relay forwards data according to the information of target IP address/port number, etc.; layer 2 (access layer) relay, that is, relay UE performs routing forwarding of control plane and user plane data in the access layer, so that an operator (that is, a core network element and a base station) can more effectively manage remote equipment (remote UE). For the relay UE node, when the data transmission rate of the ingress link (ingress link) is greater than the data transmission rate of the egress link (egress link), congestion of the egress link or overload of the data buffer may occur, and if there is no effective congestion relief scheme, the congestion is not timely relieved, which may further cause the situations such as reduction of system transmission efficiency or failure of the radio link.

In an embodiment, an embodiment of the present application provides a flow control method, where the method is applied to a first node, as shown in fig. 2, the flow control method provided in this embodiment mainly includes step S11.

S11, sending the congestion information of the exit link to the second node;

In one embodiment, the first node is a relay UE, the second node is a remote user equipment UE, and the third node is a base station.

In one embodiment, in the case that the first node is a relay UE, the second node is a remote user equipment UE, and the third node is a base station, the congestion information includes one or more of:

uu returns a link BH congestion indication message;

flow control indication information;

a second node Uu data bearing DRB identification causing Uu BH congestion;

the second node PC5 radio link control, RLC, bearer identity or logical channel identity causing uubh congestion;

uu DRB identification of the second node;

the data volume of the data of each Uu DRB to which the second node belongs cached on the first node;

congestion level of data of each Uu DRB to which the second node belongs on the first node.

In one embodiment, the method further comprises:

and the third node indicates the exit link congestion information to all remote UEs connected with the first node through an RRC reconfiguration message.

In one embodiment, the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE.

In one embodiment, in the case that the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE, the congestion information includes one or more of the following:

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB mark;

a second remote UE identity;

the entrance link SL BH RLC carries an identifier or a logical channel identifier;

the data amount of the data corresponding to the end-to-end SLRB cached at the relay UE;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

Wherein the ingress link is a link for the second node to transmit data to the first node.

In one embodiment, the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE, or the first node is a relay UE, the second node is a remote user equipment UE, and the third node is a base station, and in case that the first node is a relay UE, the congestion information is sent to the second node through one or more of the following signaling:

PC5-RRC signaling; PC5-S signaling; SL MAC CE; PC5 adaptation layer.

In one embodiment, the first node is a relay UE, the second node is a base station, and the third node is a remote UE.

In one embodiment, in a case where the first node is a relay UE, the second node is a base station, and the third node is a remote UE, the congestion information includes one or more of:

a third node identification;

side link SL BH congestion indication information;

flow control indication information;

a third node Uu DRB identification that causes SL BH congestion;

uu BH RLC bearing identification or logical channel identification causing SL BH congestion;

uu DRB identification of the third node;

the data volume of the data of each Uu DRB to which the third node belongs cached on the first node;

congestion level of data of each Uu DRB to which the third node belongs on the first node.

In one embodiment, in the case that the first node is a relay UE, the second node is a base station, and the third node is a remote UE, the congestion information is sent to the second node by one or more of the following signaling:

uu RRC signaling, Uu adaptation layer.

In one embodiment, the egress link congestion information is sent to the second node if one or more of the following conditions are met:

the first node cache load exceeds a cache threshold;

the total data volume to be transmitted cached by the first node exceeds a first data volume threshold;

the data volume of the remote UE to be transmitted cached by the first node exceeds a second data volume threshold;

the data volume to be transmitted mapped to the BH RLC channel exceeds a third data volume threshold;

the data volume of any Uu DRB in the remote end UE to be forwarded, which is cached at the first node, exceeds a fourth data volume threshold;

a first node receives a flow control polling instruction sent by a second node;

the first node sends congestion information to the second node according to the congestion information sending period;

wherein the buffering threshold, the first data amount threshold, the second data amount threshold, the third data amount threshold, the fourth data amount threshold, and the congestion information sending period are configured or preconfigured by a base station.

In an embodiment, in a case where the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE, or in a case where the first node is a relay UE, the second node is a remote UE, and the third node is a base station, the second node sends the flow control polling indication to the first node by one of the following methods:

PC5 adaptation layer PDU, PC5 RLC PDU, PC5 RRC signaling.

In one embodiment, the flow control poll indication comprises one or more of: flow control polling indication, target remote end UE identification and flow control information granularity.

In one embodiment, when the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE, or when the first node is a relay UE, the second node is a remote UE, and the third node is a base station, one of the following conditions is satisfied, and the second node sends a flow control polling indication to the first node:

initiating a flow control polling indication after interval polPDU adaptation layer PDU or RLC PDU;

after the interval polByte byte data, initiating a flow control polling indication;

wherein, the polPDU and polByte are configured or pre-configured by the base station.

In one embodiment, in the case that the first node is a relay UE, the second node is a base station, and the third node is a remote UE, the second node sends the flow control polling indication to the first node by one of the following methods:

uu adaptation layer protocol data unit PDU, Uu RLC PDU, Uu radio resource control RRC signaling.

In an embodiment, an embodiment of the present application provides a flow control method, where the method is applied to a second node, as shown in fig. 3, the flow control method provided in this embodiment mainly includes step S21.

S21, receiving the exit link congestion information sent by the first node;

In one embodiment, the method further comprises: and sending a flow control polling indication to the first node, wherein the flow control polling indication is used for indicating the first node to send the outlet link congestion information.

In one embodiment, the first node is a relay UE, the second node is a remote UE, and the third node is a base station.

In one embodiment, in a case where the first node is a relay UE, the second node is a remote UE, and the third node is a base station, the congestion information includes one or more of:

the Uu BH congestion indication information is,

the flow control indication information is transmitted to the mobile station,

the second node Uu data causing Uu BH congestion carries the DRB identity,

the second node PC5 that caused uubh congestion has either radio link control RLC bearer identity or logical channel identity,

the Uu DRB identification of the second node,

the amount of data buffered at the first node for each Uu DRB to which the second node belongs,

In one embodiment, after receiving the congestion information sent by the first node, the method further includes:

reducing the sending rate of uplink transmission data, or sending indication information to a high layer; the indication information is used for indicating the high layer to reduce the uplink transmission data volume.

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB mark;

a second remote UE identity;

the entrance SL BH RLC carries an identifier or a logical channel identifier;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

PC5 adaptation layer PDU, PC5 RLC PDU, PC5 RRC signaling.

In an embodiment, when the first node is a relay UE, the second node is a first remote UE, and the third node is a second remote UE, or when the first node is a relay UE, the second node is a remote UE, and the third node is a base station, one of the following conditions is satisfied, and a flow control polling indication is sent to the first node:

In one embodiment, in the case that the first node is a relay UE, the second node is a base station, and the third node is a far-end UE, the congestion information includes one or more of:

a third node identification;

sidelink SL BH congestion indication information,

the flow control indication information is transmitted to the mobile station,

the third node Uu DRB that caused the SL BH congestion,

the Uu BH RLC bearer identity or logical channel identity that results in SL BH congestion,

the Uu DRB identification of the third node,

the amount of data buffered at the first node for each Uu DRB to which the third node belongs,

In one embodiment, in the case that the first node is a relay UE, the second node is a base station, and the third node is a remote UE, the flow control polling indication is sent to the first node by one of the following methods:

In an embodiment, an embodiment of the present application provides a link state notification method, which is applied to a first node, as shown in fig. 4, the link state notification method provided in this embodiment mainly includes steps S31 and S32.

S31, detecting the state of a wireless link between the first node and the second node;

s32, sending the wireless link state to the third node.

In one embodiment, in case the first node is a relay UE, the second node is a remote UE, and the third node is a base station, detecting a status of a wireless link with the second node; transmitting the wireless link status to a third node, comprising:

receiving a relay reselection threshold value configured by a base station or a first threshold value reported by PC5 link quality or a second threshold value reported by PC5 link quality,

detecting a PC5 link quality PC5RSRP with the second node;

and when the PC5RSRP is lower than a relay reselection threshold or a first threshold reported by the PC5 link quality, sending the PC5RSRP to a base station.

detecting a radio link failure PC5 RLF with the second node;

sending the PC5 RLF to a third node.

In one embodiment, further comprising: when the second node detects a PC5 RLF with the first node, a relay reselection is performed.

In one embodiment, further comprising: and after the remote UE executes relay reselection and selects a new relay UE, the second node initiates RRC connection reestablishment to the base station through the new relay UE.

In one embodiment, further comprising: when detecting that the PC5RSRP between the second node reaches or is higher than the second threshold value, sending the PC5RSRP to a base station.

In one embodiment, the first node sends the PC5RSRP or the PC5 RLF to the base station by one of:

uu RRC signaling, the Uu adaptation layer controls PDUs.

In one embodiment, in a case where the first node is a relay UE, the second node is a base station, and the third node is a remote UE, the method includes:

detecting the Uu wireless link state between the base station and the base station;

and if detecting the Uu radio link failure RLF, sending Uu RLF information to the remote UE.

In one embodiment, while the Uu RLF information is transmitted to the remote UE, the method further includes:

the Uu RLF recovery is performed,

if the Uu RLF is successfully recovered, transmitting Uu RLF recovery success information to the remote UE;

and if the Uu RLF recovery fails, transmitting Uu RLF recovery failure information to the remote UE.

after Uu RLF is detected, Uu RLF recovery is carried out;

and after the Uu RLF recovery fails, transmitting Uu RLF recovery failure information to the remote UE.

In one embodiment, the Uu RLF or Uu RLF recovery success information or Uu RLF recovery failure information is sent to the remote UE by one of the following methods:

SL MIB, PC5-S signaling, PC5-RRC signaling; a newly defined SL MAC CE; PC5 adaptation layer.

In one embodiment, the method comprises: transmitting relay communication auxiliary information to the base station; and receiving the configuration information of the backhaul link bearer sent by the base station.

In one embodiment, the relay communication assistance information includes at least one of:

a relay UE indication, an L2 relay indication, an L3 relay indication, a UE-NW relay indication, a UE-UE relay indication, an L2 UE-NW relay indication, an L2 UE-UE relay indication, an L3 UE-NW relay indication, an L3 UE-UE relay indication, PC5 data flow QoS information.

In one embodiment, the backhaul link bearer configuration information includes: a packet discard timer is adapted.

In one embodiment, an L2 UE-NW relay uplink flow control method is provided.

As shown in fig. 5, for uplink, if the transmission rate of the relay UE egr Uu BH link (Uu interface backhaul link for forwarding far-end UE data) is slower than the transmission rate of the ingress PC5 BH link (PC 5 interface backhaul link for transmitting far-end UE data), it may cause congestion of uplink data transmission at the relay UE.

To alleviate congestion, the relay UE may notify the remote UE of uubh congestion information. After receiving the notification, the remote UE may reduce uplink data transmission or slow down the data transmission rate of the PC5 interface, thereby relieving the uubh congestion of the relay UE.

The Uu BH congestion information notified by the relay UE to the remote UE comprises at least one of the following information:

1) uu BH congestion indication and flow control indication; specifically, the relay UE sends uubh congestion indications to all remote UEs, and after receiving the indications, the remote UEs can further indicate to their higher layers, which reduces/slows down uplink data transmission.

2) Remote UE Uu DRB ID/PC5 RLC bearer ID/PC5 LCH ID causing relay Uu BH congestion. Specifically, the relay UE identifies which Uu BH RLC channels are congested, and notifies the relevant remote UE of Uu BH congestion according to a mapping relationship between a remote UE Uu DRB or a remote UE PC5 RLC channel and the Uu BH RLC channel, and further indicates which Uu DRB/PC5 RLC channels of the remote UE cause Uu BH congestion, so that the remote UE controls the transmission rate of the Uu DRB/PC5 RLC channels.

3) The DRB ID of the remote UE Uu and the buffer data volume or the congestion state of the DRB data at the relay UE. Specifically, the relay UE indicates to the remote UE the amount of data buffered at the relay UE for each Uu DRB to which the remote UE belongs, or the congestion status/level (high, medium, low) of the data at the relay UE for each Uu DRB to which the remote UE belongs.

How the relay UE notifies the Uu BH congestion information to the remote UE may consider any of the following methods:

1) PC5-RRC signaling; for example, PC5 RRC reconfiguration message/reconfiguration response message/measurement report message/, or newly defined PC5 RRC signaling.

2) PC5-S signaling;

3)SL MAC CE；

4) PC5 adaptation layer (adaptation layer): and an adapt control PDU, namely the Uu BH congestion information is indicated by the adaptation layer control PDU.

In addition, the base station may sense that the relay Uu BH is congested, and the base station may not allocate sufficient resources to the relay UE according to the BSR reported by the relay UE, which obviously results in a cache over load at the relay UE. But the base station does not know which uubh is congested or which far end UE has more fast data causing congestion at the relay UE. If the remote UE connected to the relay UE is configured with SL resources by the base station, the base station may reduce the SL resources allocated to the remote UE, thereby reducing the transmission rate of the remote UE. In addition, it may be considered that the base station indicates relay Uu BH congestion to all remote UEs connected to the relay UE through an RRC reconfiguration message (the RRC reconfiguration message is forwarded to the remote UEs by the relay), and the remote UEs control/slow down uplink data transmission by themselves after receiving the relay Uu BH congestion indication.

The relay UE notifies the uuBH congestion information to the remote UE when the following conditions are met:

1) when the buffer load of the relay UE exceeds a buffer threshold, or when the total data volume to be transmitted to the base station and cached at the relay UE exceeds a first data volume threshold, or when the data volume to be transmitted to a certain remote UE of the base station and cached at the relay UE exceeds a second data volume threshold, or when the data volume to be transmitted mapped to a certain uuBH RLC channel exceeds a third data volume threshold, or when the data volume to be transmitted to a certain uuDRB of the remote UE and cached at the relay UE exceeds a fourth data volume threshold; wherein the buffer threshold, the first data amount threshold, the second data amount threshold, the third data amount threshold, and the fourth data amount threshold are configured or preconfigured by a base station.

2) When the relay UE receives a flow control Polling (Polling) indication sent by the remote UE, the relay UE sends Uu BH congestion information to the remote UE. The remote UE may send the flow control polling indication via PC5 RRC signaling or PC5 adaptation layer PDU or PC5 RLC PDU. Wherein the flow control polling indication may comprise one or more of: flow control polling indication, remote UE identification and flow control information granularity. The flow control information granularity comprises at least one of: flow control indication/buffer size/buffer status of per UE/per equations BH bearer/per end-to-end bearer. Optionally, a scenario may be defined in which the remote UE sends flow control polling: i) initiating poling once after most of poll PDU adaptation layer PDU or RLC PDU intervals; ii) initiating polling once after maximum interval polByte byte data; wherein, the polPDU and polByte are configured or pre-configured by the base station.

3) The relay UE informs the uuBH congestion information to the remote UE according to the congestion information sending period, wherein the congestion information sending period is configured or preconfigured by the base station.

In one embodiment, an L2 UE-NW relay downlink flow control method is provided.

As shown in fig. 6, for the downlink, if the relay UE ingress Uu BH transmission rate is faster than the egr PC5 BH transmission rate, it may cause congestion at the relay UE for data transmission to some target remote UEs.

In order to alleviate the congestion, the relay UE needs to inform the base station of the SL communication congestion information with the target remote UE, so that the base station slows down the downlink data transmission for the target remote UE.

The SL BH congestion information notified to the base station by the relay UE may include at least one of:

1) target remote UE ID: informing the base station which far-end UE the SL BH transmission is congested for.

2) SL BH congestion indication, or flow control indication;

3) remote UE Uu DRB ID/Uu BH RLC bearer ID/Uu LCH ID causing SL BH congestion. Specifically, the relay UE determines which PC5 BH RLC channel is congested, identifies which Uu DRB/Uu BH RLC of the remote UE causes the congestion of the PC5 BH RLC channel according to the mapping relation between the Uu DRB or the Uu BH RLC and the PC5 BH RLC channel, and indicates the Uu DRB ID/Uu BH RLC bearer ID/LCH ID of the remote UE to the base station.

4) The DRB ID of the remote UE Uu and the buffer data volume or the congestion state of the DRB data at the relay UE. The relay UE identifies the amount of buffered data or congestion status/level (high, medium, low, or congested, uncongested indication) of data at the relay UE for each Uu DRB of the remote UE to which it belongs.

The relay UE notifies the base station of the SL BH congestion information by any of the following means:

uu RRC signaling: SUI;

uu adaptation layer (adaptation layer): and an adapt control PDU, namely SL BH congestion information is indicated through a Uu adaptation layer control PDU.

The relay UE notifies the base station of SL BH congestion information when any of the following conditions are met:

1) when the buffer load of the relay UE exceeds a buffer threshold, or when the total data volume to be transmitted by the PC5 interface and buffered at the relay UE exceeds a first data volume threshold, or when the data volume to be transmitted to a certain remote UE and buffered at the relay UE exceeds a second data volume threshold, or when the data volume to be transmitted mapped to a certain PC5 BH RLC channel exceeds a third data volume threshold, or when the data volume to be transmitted of a certain Uu DRB and buffered at the relay UE and to be forwarded at the remote UE exceeds a fourth data volume threshold; wherein the buffer threshold, the first data amount threshold, the second data amount threshold, the third data amount threshold, and the fourth data amount threshold are configured or preconfigured by a base station.

2) When the relay UE receives a flow control Polling (Polling) indication sent by the base station, the relay UE sends SL BH congestion information to the base station. More specifically, the flow control Polling (Polling) indication may comprise at least one of: flow control polling indication, target remote UE ID (specifically flow control information for a certain target remote UE), and flow control information granularity (flow control indication/buffer size/buffer status of per UE/per e exit BH bearer/per end-to-end bearer). The base station may send the flow control polling indication via a Uu adapt PDU (e.g., an assembly polling adapt control PDU, where flow control polling is indicated via a PDU type) or a Uu RLC PDU or Uu RRC signaling.

3) And the relay UE informs the base station of SL BH congestion information according to a congestion information sending period, wherein the congestion information sending period is configured or preconfigured by the base station.

In one embodiment, an L2 UE-UE relay flow control method is provided.

As shown in FIG. 7, assume that the remote UE1 is a source UE and the remote UE2 is a destination UE, i.e., the data flow is remote UE1- > relay UE- > remote UE 2. The relay UE may forward data for multiple different source, destination remote UEs.

If the data transmission rate of the greress link (relay UE sends data to remote UE2) of the relay UE is slower than the data transmission rate of the ingress link (remote UE1 sends data to relay UE), then it may result in buffer overload or congestion of the egress link data transmission at the relay UE. To alleviate congestion, a flow control method may be considered in which the relay UE notifies the remote UE1 of the egresslink congestion information, or the relay UE instructs the remote UE1 to perform/initiate flow control. In particular, the amount of the solvent to be used,

the relay UE informing (source) the remote UE of the SL BH congestion information on the egr link includes at least one of:

1) congestion indication of Egress SL BH, or flow control indication;

2) destination remote UE ID: indicating to which target remote UE the link/data transmission is congested;

3) End-to-End SLRB ID: the indication is which end-to-end SLRB between the source remote UE and destination remote UE causes the egr link to be congested. The relay UE identifies which SL BH RLC channels on the egres link are congested, and determines which end-to-end SLRBs of the remote UE cause the congestion of the egres link according to the mapping relation between the end-to-end SLRBs and the egres SL BH RLC channels. And after receiving the indication, the source remote UE can control the transmission rate of the SLRBs or reduce the data volume.

4) Ingress SL BH RLC bearer ID/LCH ID: indicating which ingress SL BH RLC bearer between source remote UE and relay UE causes the egress link to be congested. The relay UE identifies which SL BH RLC channels on the egress link are congested, and determines which ingress SL BH RLC channels of which remote UEs cause the egress link to be congested according to the mapping relation between the ingress SL BH RLC channels and the egress SL BH RLC channels.

5) End-to-End SLRB ID and corresponding buffer size/status at the relay UE. Specifically, the relay UE indicates to the remote UE the amount of data buffered at the relay UE (for the equalising link direction) for the data belonging to each end-to-end SLRB, or the congestion status/level (high, medium, low) of the data belonging to each end-to-end SLRB at the relay UE (for the equalising link direction).

The relay UE notifies the (source) remote UE of the egr link SL BH congestion information in any mode as follows:

PC5-RRC signaling; PC5-S signaling; SL MAC CE; PC5 adapt layer (adapt control PDU).

The relay UE notifies (source) the remote UE of the egr link SL BH congestion information when the following arbitrary conditions are met:

1) when the buffer load of the relay UE exceeds a buffer threshold, or when the total data volume to be transmitted cached at the relay UE exceeds a first data volume threshold, or when the data volume to be transmitted to a certain dest remote UE cached at the relay UE exceeds a second data volume threshold, or when the data volume to be transmitted mapped to a certain PC5 BH RLC channel exceeds a third data volume threshold, or when the data volume of a certain end-to-end SLRB to be forwarded at the relay UE exceeds a fourth data volume threshold; wherein the buffer threshold, the first data volume threshold, the second data volume threshold, the third data volume threshold, and the fourth data volume threshold are configured or preconfigured by a base station.

2) When the relay UE receives a flow control Polling (Polling) indication sent by the source remote UE, the relay UE sends egr SL BH congestion information to the source remote UE. More specifically, the flow control Polling (Polling) indication may include at least one of: a flow control polling indication, a target remote UE ID (specifically, flow control information for a certain target remote UE), and a flow control information granularity (flow control indication/buffer size/buffer status of per UE/per aggregation BH bearer/per end-to-end bearer). The remote UE may send the flow control polling indication via PC5 RRC signaling or PC5 adapt PDU or PC5 RLC PDU. Optionally, a condition for sending the flow control polling by the remote UE may be defined: i) after the polPDU or RLC PDU is spaced, initiating poling once; ii) initiating polling once after interval polByte byte data; wherein, the polPDU and polByte are configured or pre-configured by the base station.

3) The relay UE informs the base station of the congestion link SL BH congestion information according to the congestion information sending period, wherein the congestion information sending period is configured or preconfigured by the base station. When the data flow is reversed, as is the case by far end UE2, relay UE, far end UE1, far end UE2 is symmetrical to far end UE 1.

In one embodiment, an L2 UE-NW relay RLF notification method is provided.

Case 1: PC5 RLF occurs between the remote UE and the relay UE. As shown in fig. 8.

When the remote UE detects PC5 RLF, it can trigger to perform UE-NW relay (re-) selection, or cell selection, or UE-UE relay selection, looking for a UE-UE relay connected to the relay UE 1.

After the remote UE performs relay reselection and selects a new relay UE, the second node initiates RRC connection reestablishment to the base station through the new relay UE.

The relay UE also obtains a relay (re-) selection threshold (or a new configured threshold), and reports the PC5RSRP to the base station when the relay UE detects that the PC5RSRP reaches the threshold. Let the base station know that the link quality of PC5 is deteriorating, the remote UE performs relay reselection, or the base station performs relay reselection for the remote UE. Optionally, before the remote UE switches the relay, if the relay UE detects that the PC5RSRP recovers to/is higher than a certain threshold, the relay UE updates and reports the PC5 RSRP.

After the relay UE detects the PC5 RLF, the relay UE may inform the base station of the PC5 RLF so that the base station stops downlink transmission for the remote UE and releases the remote UE configuration/context, or the base station does not immediately release the remote UE context but waits for the remote UE to initiate RRC connection re-establishment through a new relay UE or a direct Uu link. The relay UE may inform the base station of the PC5 RLF Information of the relay UE and the remote UE through Uu RRC signaling (e.g., Sidelink UE Information, or other RRC signaling), or Uu adaptation layer control PDU. Specifically, the RRC signaling or Uu adaptation layer control PDU contains the remote UE identity, PC5 RLF indication.

Case 2: the relay UE generates Uu RLF.

As shown in fig. 9, in the Uu interface, when the relay UE detects Uu RLF, the relay UE searches for a survivable cell to initiate RRC reestablishment. For UE-NW relay communication, when the relay UE detects Uu RLF, the time for searching for a viable cell and RRC reestablishment may be several tens of seconds, if the RLF recovery fails, the remote UE is notified, and the remote UE performs other preparation (such as relay reselection or cell selection), which may delay a long time. Therefore, it is proposed that when the relay UE detects Uu RLF, the remote UE is notified so that the remote UE can make other preparations in time; and meanwhile, the relay UE performs Uu RLF recovery, if the Uu RLF recovery of the relay UE is successful, the relay UE sends a Uu RLF recovery success indication to the remote UE, and if the Uu RLF recovery of the relay UE fails, the relay UE further sends a Uu RLF recovery failure indication to the remote UE.

In another embodiment, the remote UE is not notified immediately after the Uu RLF is detected, but the Uu RLF recovery failure indication information is sent to the remote UE after the Uu RLF recovery failure.

How the relay UE informs the remote UE of the Uu RLF/Uu RLF recovery success/Uu RLF recovery failure:

SL MIB: the signaling overhead is low, and the UE in the relay communication range can receive the information; however, the SL MIB has a period, and the SL MIB can be sent only after the next SL MIB period is needed, which is not timely enough;

PC5-S signaling: e.g. relay UE initiating PC5-S release and carrying a cause value (Uu RLF); the relay UE AS layer needs to inform the Uu state to the V2X layer, and interlayer interaction is increased;

PC5-RRC signaling;

passing the newly defined SL MAC CE;

the adaptation layer is indicated by a PC5, i.e. by a PC5 adaptation layer control PDU.

In one embodiment, an L2 UE-UE relay QoS guarantee method is provided.

For L2 UE-UE Relay, when a source UE (remote UE1) wants to establish a unicast connection with a target UE (remote UE2), the source UE decides the end-to-end E2E QoS based on application layer requirements. E2E QoS, especially PDB, needs to be split over two segments of PC5(remote UE1 and relay UE, relay UE and remote UE 2). The Relay UE divides the E2E QoS into two parts: source PC5 QoS (remote UE1 and relay UE), and target PC5 QoS (relay UE and remote UE 2). The Relay UE ensures that the PDB/PER associated with PQI in the source PC5 QoS and the PDB/PER associated with PQI in the target PC5 QoS support E2E PDB/PER. The Relay UE also ensures that other QoS parameters in the source and destination PC5 QoS are compatible (e.g. same value).

Specifically, the source UE sends E2E QoS corresponding to PC5 QoS flow to Relay UE, the Relay UE performs QoS (pdb) segmentation, determines source PC5 QoS and target PC5 QoS, sends target PC5 QoS corresponding to PC5 QoS flow to the target UE, and sends source PC5 QoS corresponding to PC5 QoS flow to the source UE. The target PC5 QoS includes the segmented target PDB (PDB to be satisfied between relay UE and remote UE2), and in implementation, the PDB is guaranteed by a packet discard timer (discardTimer) of the PDCP layer. But for the L2 Relay UE, there is no PDCP layer, and in order to guarantee the target-end PDB, the packet dropping function may be supported by an adaptation layer (adaptation layer) of the Relay UE. Specifically, the Relay UE adaptation layer maintains a packet discard timer discard for each adapt SDU, starts the discard timer when the Relay UE receives the adapt SDU, and discards the adapt SDU/PDU if the discard timer is not timed out and has not sent out the adapt SDU/PDU. Wherein the value of the packet discard timer of the adaptation layer is configured in the BH bearer configuration.

If the Relay UE is in the RRC connection state, the Relay UE sends a Relay indication sum or a target end QoS corresponding to a PC5 QoS flow to the base station, and the base station configures a target end backhaul link bearer for the Relay UE through an RRC dedicated signaling (namely, a BH RLC channel between the Relay UE and a remote UE2, which can be called a Relay BH RLC channel). Wherein the relay indication comprises at least one of: l2 relay indication, L3 relay indication, UE-NW relay indication, UE-UE relay indication, L2 UE-NW relay indication, L2 UE-UE relay indication, L3 UE-NW relay indication, L3 UE-UE relay indication. Specifically, the relay backhaul link bearer configuration information includes at least one of: the mapping relation of end-to-end SLRB and relay BH RLC channel, the mapping relation of BH RLC channel between source UE and relay UE and BH RLC channel between relay UE and target UE, the mapping relation of ingress link BH RLC channel and egress link BH RLC channel, adaptive packet discarding timer discard, relay BH RLC channel identification, relay BH logical channel identification, RLC configuration and logical channel configuration.

If the Relay UE is in an RRC idle/inactive state, the Relay UE obtains the Relay backhaul link bearer configuration information from the system message, wherein the Relay backhaul link bearer configuration information comprises an adaptation layer discardTimer. If the Relay UE is uncovered, the Relay UE obtains the Relay backhaul link bearer configuration information from the preconfigured side link information, wherein the Relay backhaul link bearer configuration information comprises an adaptation layer discardTimer.

A backhaul link bearer configuration method applied to a first node includes:

transmitting the relay communication assistance information to the base station,

and receiving the configuration information of the backhaul link bearer sent by the base station.

Wherein the relay communication assistance information includes at least one of: relay UE indication, L2 relay indication, L3 relay indication, UE-NW relay indication, UE-UE relay indication, L2 UE-NW relay indication, L2 UE-UE relay indication, L3 UE-NW relay indication, L3 UE-UE relay indication, PC5 data stream QoS information.

The backhaul link bearer configuration information includes at least an adaptation layer packet drop timer discardTimer.

In an embodiment, an embodiment of the present application provides a flow control device, where the flow control device is configured at a first node, as shown in fig. 10, the flow control device provided in this embodiment mainly includes a first sending module 101.

A first sending module 101 configured to send egress link congestion information to the second node;

In one embodiment, the congestion information includes one or more of:

uu returns a link BH congestion indication message;

flow control indication information;

a second node Uu data bearing DRB identification causing Uu BH congestion;

uu DRB identification of the second node;

In one embodiment, the method further comprises:

In one embodiment, the congestion information includes one or more of:

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB mark;

a second remote UE identity;

the entrance SL BH RLC carries an identifier or a logical channel identifier;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

In one embodiment, the congestion information is sent to the second node by one or more of the following signaling:

PC5-RRC signaling; PC5-S signaling; SL MAC CE; PC5 adaptation layer.

In one embodiment, the congestion information includes one or more of:

a third node identification;

side link SL BH congestion indication information;

flow control indication information;

a third node Uu DRB identification that causes SL BH congestion;

uu DRB identification of the third node;

uu RRC signaling, Uu adaptation layer.

the first node cache load exceeds a cache threshold;

a first node receives a flow control polling instruction sent by a second node;

The flow control device provided in the embodiment can execute the flow control method provided in any embodiment of the invention, and has corresponding functional modules and beneficial effects for executing the method. For details of the flow control method provided in any embodiment of the present invention, reference may be made to the technical details not described in detail in this embodiment.

It should be noted that, in the embodiment of the flow control device, the included units and modules are merely divided according to the functional logic, but are not limited to the above division as long as the corresponding functions can be realized; in addition, specific names of the functional units are only used for distinguishing one functional unit from another, and are not used for limiting the protection scope of the application.

In an embodiment, an embodiment of the present application provides a flow control device, where the flow control device is configured at a second node, as shown in fig. 11, the flow control device provided in this embodiment mainly includes a receiving module 111.

A receiving module 111 configured to receive egress link congestion information sent by a first node;

In one embodiment, the congestion information includes one or more of:

the Uu BH congestion indication information is,

the flow control indication information is transmitted to the mobile station,

the second node Uu data causing Uu BH congestion carries the DRB identity,

the Uu DRB identification of the second node,

In one embodiment, the congestion information includes one or more of:

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB mark;

a second remote UE identity;

the entrance SL BH RLC carries an identifier or a logical channel identifier;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

In one embodiment, the second node sends the flow control poll indication to the first node by one of:

PC5 adaptation layer PDU, PC5 RLC PDU, PC5 RRC signaling.

In one embodiment, one of the following conditions is met, and a flow control polling indication is sent to the first node:

In one embodiment, the congestion information includes one or more of:

a third node identification;

sidelink SL BH congestion indication information,

the flow control indication information is transmitted to the mobile station,

the third node Uu DRB that caused the SL BH congestion,

the Uu DRB identification of the third node,

In an embodiment, an embodiment of the present application provides a link status notification apparatus, where the apparatus is configured at a first node, as shown in fig. 12, the link status notification method provided in this embodiment mainly includes a detection module 121 and a second sending module 122.

A detection module 121 configured to detect a status of a wireless link with a second node;

a second transmitting module 122 configured to transmit the wireless link status to a third node.

detecting a PC5 link quality PC5RSRP with the second node;

detecting a radio link failure PC5 RLF with the second node;

sending the PC5 RLF to a third node.

uu RRC signaling, the Uu adaptation layer controls PDUs.

the Uu RLF recovery is performed,

after Uu RLF is detected, Uu RLF recovery is carried out;

The link state notification device provided in the embodiment can execute the link state notification method provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method. For details of the technique not described in detail in this embodiment, reference may be made to a link status notification method provided in any embodiment of the present invention.

It should be noted that, in the embodiment of the link status notification apparatus, each included unit and module are only divided according to functional logic, but are not limited to the above division as long as the corresponding functions can be implemented; in addition, specific names of the functional units are only used for distinguishing one functional unit from another, and are not used for limiting the protection scope of the application.

Fig. 13 is a schematic structural diagram of an apparatus provided in the embodiment of the present application, and as shown in fig. 13, the apparatus includes a processor 131, a memory 132, an input device 133, an output device 134, and a communication device 135; the number of the processors 131 in the device may be one or more, and one processor 131 is taken as an example in fig. 13; the processor 131, the memory 132, the input device 133 and the output device 134 in the apparatus may be connected by a bus or other means, and the bus connection is exemplified in fig. 13.

The memory 132, which is a computer-readable storage medium, may be used to store software programs, computer-executable programs, and modules. The processor 131 executes various functional applications and data processing of the device by executing software programs, instructions and modules stored in the memory 132, namely, implements any method provided by the embodiments of the present application.

The memory 132 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required for at least one function; the storage data area may store data created according to use of the device, and the like. Further, the memory 132 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some examples, memory 132 may further include memory located remotely from processor 131, which may be connected to devices over a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The input device 133 is operable to receive input numeric or character information and to generate key signal inputs relating to user settings and function controls of the apparatus. The output device 134 may include a display device such as a display screen.

The communication device 135 may include a receiver and a transmitter. The communication device 135 is configured to perform information transceiving communication according to the control of the processor 131.

In an exemplary embodiment, the present application further provides a storage medium containing computer-executable instructions, which when executed by a computer processor, perform a method for flow control, the method being applied to a first node, including:

sending egress link congestion information to the second node;

Of course, the storage medium provided in the embodiments of the present application contains computer-executable instructions, and the computer-executable instructions are not limited to the method operations described above, and may also perform related operations in the flow control method provided in any embodiment of the present application.

In an exemplary embodiment, the present application further provides a storage medium containing computer-executable instructions, which when executed by a computer processor, perform a method for flow control, the method being applied to a second node, including:

receiving exit link congestion information sent by a first node;

In an exemplary embodiment, the present application further provides a storage medium containing computer-executable instructions, which when executed by a computer processor, perform a method of link state notification, the method applied to a first node, including:

detecting a state of a wireless link with a second node;

transmitting the wireless link status to a third node.

Of course, the storage medium provided in the embodiments of the present application and containing computer-executable instructions is not limited to the method operations described above, and may also perform related operations in the link state notification method provided in any embodiment of the present application.

From the above description of the embodiments, it is obvious for those skilled in the art that the present application can be implemented by software and necessary general hardware, and certainly can be implemented by hardware, but the former is a better embodiment in many cases. Based on such understanding, the technical solutions of the present application may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as a floppy disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a FLASH Memory (FLASH), a hard disk or an optical disk of a computer, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the methods described in the embodiments of the present application.

The above description is only exemplary embodiments of the present application, and is not intended to limit the scope of the present application.

It will be clear to a person skilled in the art that the term user terminal covers any suitable type of wireless user equipment, such as a mobile phone, a portable data processing device, a portable web browser or a car mounted mobile station.

In general, the various embodiments of the application may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the application is not limited thereto.

Embodiments of the application may be implemented by a data processor of a mobile device executing computer program instructions, for example in a processor entity, or by hardware, or by a combination of software and hardware. The computer program instructions may be assembly instructions, Instruction Set Architecture (ISA) instructions, machine related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages.

Any logic flow block diagrams in the figures of this application may represent program steps, or may represent interconnected logic circuits, modules, and functions, or may represent a combination of program steps and logic circuits, modules, and functions. The computer program may be stored on a memory. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), optical storage devices and systems (digital versatile disc, DVD, or CD disc), etc. The computer readable medium may include a non-transitory storage medium. The data processor may be of any type suitable to the local technical environment, such as but not limited to general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), programmable logic devices (FGPAs), and processors based on a multi-core processor architecture.

The foregoing has provided by way of exemplary and non-limiting examples a detailed description of exemplary embodiments of the present application. Various modifications and adaptations to the foregoing embodiments may become apparent to those skilled in the relevant arts in view of the following drawings and the appended claims, without departing from the scope of the invention. Therefore, the proper scope of the invention is to be determined according to the claims.

Claims

1. A flow control method applied to a first node comprises the following steps:

sending egress link congestion information to the second node;

2. The method of claim 1, wherein the first node is a relay UE, wherein the second node is a remote user equipment UE, and wherein the third node is a base station.

3. The method of claim 2, wherein the congestion information comprises one or more of:

uu returns a link BH congestion indication message;

flow control indication information;

a second node Uu data bearing DRB identification causing Uu BH congestion;

uu DRB identification of the second node;

4. The method of claim 2, further comprising:

5. The method of claim 1, wherein the first node is a relay UE, wherein the second node is a first remote UE, and wherein the third node is a second remote UE.

6. The method of claim 5, wherein the congestion information comprises one or more of:

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB identification;

a second remote UE identity;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

7. The method according to claim 2 or 5, characterized in that the congestion information is sent to the second node by one or more of the following signalling:

PC5-RRC signaling; PC5-S signaling; SL MAC CE; PC5 adaptation layer.

8. The method of claim 1, wherein the first node is a relay UE, wherein the second node is a base station, and wherein the third node is a remote UE.

9. The method of claim 8, wherein the congestion information comprises one or more of:

a third node identification;

side link SL BH congestion indication information;

flow control indication information;

a third node Uu DRB identification that causes SL BH congestion;

uu DRB identification of the third node;

10. The method of claim 8, wherein the congestion information is sent to the second node by one or more of:

uu RRC signaling, Uu adaptation layer.

11. The method of claim 1, wherein the egress link congestion information is sent to the second node if one or more of the following conditions are met:

the first node cache load exceeds a cache threshold;

the data volume of any Uu DRB or end-to-end SLRB in the remote end UE to be forwarded, cached at the first node, exceeds a fourth data volume threshold;

a first node receives a flow control polling instruction sent by a second node;

12. The method of claim 11, wherein the flow control poll indication comprises one or more of:

flow control polling indication, target remote UE identification and flow control information granularity.

13. A flow control method applied to a second node comprises the following steps:

receiving exit link congestion information sent by a first node;

14. The method of claim 13, further comprising:

and sending a flow control polling indication to the first node, wherein the flow control polling indication is used for indicating the first node to send the outlet link congestion information.

15. The method of claim 13, wherein the first node is a relay UE, wherein the second node is a remote UE, and wherein the third node is a base station.

16. The method of claim 15, wherein the congestion information comprises one or more of:

the Uu BH congestion indication information is,

the flow control indication information is transmitted to the mobile station,

the second node Uu data causing Uu BH congestion carries the DRB identity,

the Uu DRB identification of the second node,

17. The method of claim 15, wherein after receiving the congestion information sent by the first node, the method further comprises:

reducing the sending rate of uplink transmission data, or sending indication information to a high layer; the indication information is used for indicating a high layer to reduce the uplink transmission data volume.

18. The method of claim 13, wherein the first node is a relay UE, wherein the second node is a first remote UE, and wherein the third node is a second remote UE.

19. The method of claim 18, wherein the congestion information comprises one or more of:

an egress link SL BH congestion indication information;

flow control indication information;

end-to-end SLRB identification;

a second remote UE identity;

congestion level of data corresponding to the end-to-end SLRB at the relay UE.

20. A method according to claim 15 or 18, wherein the second node sends the flow control poll indication to the first node by one of:

PC5 adaptation layer PDU, PC5 RLC PDU, PC5 RRC signaling.

21. The method according to claim 15 or 18, wherein one of the following conditions is met, and wherein a flow control poll indication is sent to the first node:

22. The method of claim 13, wherein the first node is a relay UE, wherein the second node is a base station, and wherein the third node is a remote UE.

23. The method of claim 22, wherein the congestion information comprises one or more of:

a third node identification;

sidelink SL BH congestion indication information,

the flow control indication information is transmitted to the mobile station,

the third node Uu DRB that caused the SL BH congestion,

the Uu DRB identification of the third node,

24. The method of claim 22, wherein the flow control poll indication is sent to the first node by one of:

25. A link state notification method applied to a first node, comprising:

detecting a state of a wireless link with a second node;

transmitting the wireless link status to a third node.

26. The method of claim 25, wherein the first node is a relay UE, wherein the second node is a remote UE, and wherein the third node is a base station.

27. The method of claim 26, wherein detecting the status of the wireless link with the second node; transmitting the wireless link status to a third node, comprising:

receiving a relay reselection threshold configured by a base station or a first threshold reported by PC5 link quality or a second threshold reported by PC5 link quality,

detecting a PC5 link quality PC5RSRP with the second node;

28. The method of claim 27, further comprising:

when detecting that the PC5RSRP between the second node and the second node reaches or is higher than the second threshold value, sending the PC5RSRP to a base station.

29. The method of claim 26, wherein detecting the status of the wireless link with the second node; transmitting the wireless link status to a third node, comprising:

detecting a radio link failure PC5 RLF with the second node;

sending the PC5 RLF to a third node.

30. The method of claim 25, further comprising:

when the second node detects a PC5 RLF with the first node, a relay reselection is performed.

31. The method of claim 30, further comprising:

and after the second node executes relay reselection and selects a new relay UE, the second node initiates RRC connection reestablishment to the base station through the new relay UE.

32. A method according to claim 27 or 28, characterised in that the first node sends PC5RSRP or PC5 RLF to the base station by one of:

uu RRC signaling, the Uu adaptation layer controls PDUs.

33. The method of claim 25, wherein the first node is a relay UE, wherein the second node is a base station, and wherein the third node is a remote UE.

34. The method of claim 33, comprising:

35. The method of claim 34, wherein while transmitting Uu RLF information to a remote UE, the method further comprises:

the Uu RLF recovery is performed,

36. The method of claim 33, comprising:

after Uu RLF is detected, Uu RLF recovery is carried out;

37. The method according to any of claims 34-36, wherein the Uu RLF or Uu RLF recovery success information or Uu RLF recovery failure information is sent to the remote UE by one of:

SL MIB, PC5-S signaling, PC5-RRC signaling, newly defined SL MAC CE, PC5 adaptation layer.

38. The method of claim 25, wherein the method comprises:

transmitting relay communication auxiliary information to the base station;

39. The method of claim 38, wherein the relay communication assistance information comprises at least one of:

40. The method of claim 38, wherein the backhaul link carrying configuration information comprises: a packet discard timer is adapted.

41. A flow control apparatus, the apparatus being configured at a first node, comprising:

42. A flow control apparatus, the apparatus being configured at a second node, comprising:

43. A link state notification apparatus, the apparatus being configured at a first node, comprising:

44. An apparatus, comprising:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement any of the methods.

45. A storage medium, characterized in that the storage medium stores a computer program which, when executed by a processor, implements any of the methods.