CN113875314A - Wireless communication method and device - Google Patents

Abstract

The application provides a method of wireless communication, comprising: the first access backhaul integrated IAB node determines that at least one of the following trigger conditions is satisfied: the first IAB node receives an access request sent by a child node, the child node comprises a second IAB node and/or User Equipment (UE), the first IAB node receives a paging message triggered by a host node, the first IAB node has data to be sent, and an RRC layer or an F1AP layer of the first IAB node receives an upper layer connection recovery indication; the first IAB node triggers a wireless connection restoration with the host node. When the first IAB node meets the triggering condition, the wireless connection with the host node is recovered, and the power consumption is reduced while the communication requirement is met.

Description

Wireless communication method and device Technical Field

The present application relates to the field of communications, and in particular, to a method and an apparatus for wireless communication.

Background

In order to meet the ultra-high capacity requirement of the 5th generation (5G) mobile communication system, high-frequency small-station networking is the mainstream. The high-frequency carrier wave has poor propagation characteristics, serious shielding attenuation and low coverage range, so that a large number of densely deployed small stations are required. Accordingly, it is very costly and difficult to construct the optical fiber backhaul provided for these numerous densely deployed small stations, and therefore an economical and convenient backhaul scheme is required. In addition, from the perspective of wide coverage requirement, network coverage is provided in some remote areas, the deployment difficulty of optical fibers is high, the cost is high, and a flexible and convenient access and return scheme also needs to be designed. An Integrated Access and Backhaul (IAB) technology provides an idea for solving the above problems. An access link (access link) and a backhaul link (backhaul link) of the IAB network both adopt a wireless transmission scheme, so that optical fiber deployment can be avoided.

In some cases, there is no connected user equipment in the cell covered by the IAB node, and the power consumption is large when the wireless connection with the host node is maintained.

Disclosure of Invention

The application provides a wireless communication method and device, which can reduce power consumption of an IAB node while meeting communication requirements.

In a first aspect, a method of wireless communication is provided, including: the first access backhaul integrated IAB node determines that any one or more of the following trigger conditions are met: the first IAB node receives an access request sent by a child node, the child node comprises a second IAB node and/or User Equipment (UE), the first IAB node receives a paging message triggered by a host node, the first IAB node has data to be sent, and an RRC layer or an F1AP layer of the first IAB node receives an upper layer connection recovery indication; the first IAB node triggers a wireless connection restoration with the host node.

When the first IAB node meets the triggering condition, the wireless connection with the host node is recovered, and the power consumption is reduced while the communication requirement is met.

With reference to the first aspect, in some possible implementations, before the first IAB node triggers restoration of a radio connection with a host node, the method further includes: the first IAB node obtains an access mark corresponding to the trigger condition according to the trigger condition; the first IAB node carries out access control verification according to the access mark; the first IAB node triggering a wireless connection restoration with a host node, comprising: and when the access control check is passed, the first IAB node triggers the recovery of the wireless connection with the host node.

Before the wireless connection is restored, the first IAB node performs an access control check to determine whether the access is allowed, i.e., whether the wireless connection is allowed to be restored.

With reference to the first aspect, in some possible implementations, the access label is an access label associated with an IAB node.

The IAB is configured with the access mark different from that of the UE, so that the wireless connection recovery of the UE and the IAB can be processed differently, and the flexibility is improved.

With reference to the first aspect, in some possible implementation manners, the obtaining, by the first IAB node, an access flag corresponding to a trigger condition according to the trigger condition being met includes: according to the satisfied trigger condition, the non-access stratum (NAS) of the first IAB node obtains the access event corresponding to the satisfied trigger condition, wherein the access event is an access event associated with the IAB node; and the first IAB node obtains the access mark corresponding to the access event according to the access event.

The IAB is configured with the access event different from the UE, the same or different treatment can be carried out on the wireless connection recovery of the UE and the IAB, and the flexibility is improved.

With reference to the first aspect, in some possible implementations, the method further includes: the first IAB node sends a wireless connection recovery request message to a host node, wherein the wireless connection recovery request message comprises reason indication information, and the reason indication information corresponds to the satisfied trigger condition.

The host node can know the reason for the wireless connection recovery of the first IAB node according to the reason indication information, and can perform the same or different processing on different reasons, thereby improving the flexibility.

With reference to the first aspect, in some possible implementations, the method further includes: the first IAB node sends IAB node indication information to a host node, wherein the IAB node indication information is used for indicating that the wireless connection recovery is the wireless connection recovery of the IAB node.

The host node can perform the same or different processing on the wireless connection restoration of the UE and the IAB node according to the indication information of the IAB node, thereby improving the flexibility.

With reference to the first aspect, in some possible implementation manners, the satisfied trigger condition includes that the first IAB node receives access requests sent by child nodes, where a number of the access requests is greater than or equal to a threshold value, or a number of the child nodes is greater than or equal to the threshold value.

The first IAB node may trigger the recovery of the wireless connection with the host node when receiving a certain number of access requests or receiving access requests sent by a certain number of child nodes, thereby further reducing power consumption.

With reference to the first aspect, in some possible implementations, before the first IAB node determines that a trigger condition is satisfied, the method further includes: and the first IAB node receives the threshold value sent by the host node.

The donor base station may configure a threshold value for the first IAB node. The host node can configure the threshold value according to the load condition and the like, and the flexibility is improved.

With reference to the first aspect, in some possible implementation manners, the first IAB node is a relay device or a device providing data backhaul, and the host node is a base station.

With reference to the first aspect, in some possible implementation manners, the paging message is sent by the host node under a condition that the host node receives downlink data of an inactive UE and/or the host node receives a first paging message of an idle UE.

In a second aspect, a method of wireless communication is provided, comprising: the first host node determines that any one or more of the following trigger conditions are met: the first host node receives downlink data of non-activated UE, and receives a first paging message of idle UE; the first host node sends a second paging message to the first access backhaul integrated IAB, wherein the second paging message is used for indicating the first IAB to trigger the recovery of the wireless connection between the first IAB and a host node, and the host node is the first host node or a second host node.

When the host node meets the trigger condition, the host node sends a paging message to the first IAB node to indicate the first IAB node to trigger and recover the wireless connection with the host node, and the power consumption is reduced while the communication requirement is met.

With reference to the second aspect, in some possible implementations, the triggering condition met includes that the first host node receives downlink data of the inactive UE, and before the first host node sends the second paging message to the first IAB node, the method further includes: and the first host node determines the first IAB node according to a Radio Access Network (RAN) notification area of the UE in an inactive state.

When the host node meets the trigger condition, the IAB node is paged in a specific range to indicate the IAB node to trigger the recovery of the wireless connection between the IAB node and the host node, and the power consumption is reduced while the communication requirement is met.

With reference to the second aspect, in some possible implementations, the trigger condition that is met includes that the first host node receives a first paging message of an idle UE, and before the first host node sends a second paging message to the first IAB node, the method further includes: and the first host node determines the first IAB node according to a Tracking Area Identification (TAI) list of the first paging message.

When the host node meets the trigger condition, the IAB node is paged in a specific range to indicate the IAB node to trigger the recovery of the wireless connection between the IAB node and the host node, and the power consumption is reduced while the communication requirement is met.

With reference to the second aspect, in some possible implementations, the method further includes: the first host node receives a wireless connection recovery request message sent by the first IAB node; the first host node sends a context request to a third host node, where the context request is used to request the third host node to send correspondence information between a distributed unit DU of the first IAB node and a mobile terminal MT of the first IAB node; and the first host node receives the corresponding relation information sent by the third host node.

With reference to the second aspect, in some possible implementation manners, the correspondence information includes: the DU identifier of the DU of the first IAB node and the inactive radio network temporary identifier I-RNTI of the MT of the first IAB node, and/or the new radio cell global identifier NR CGI of the DU of the first IAB node and the I-RNTI of the MT of the first IAB node.

With reference to the second aspect, in some possible implementation manners, the radio connection restoration request message carries an identifier of a first IAB node, and the identifier of the first IAB node includes an identifier of the third host node.

With reference to the second aspect, in some possible implementations, the first IAB node is a relay device or a device providing data backhaul, and the first host node is a base station.

In a third aspect, an access backhaul integrated IAB apparatus is provided, including: a determination module configured to determine that any one or more of the following trigger conditions are satisfied: the IAB device receives an access request sent by a child node, wherein the child node comprises a second IAB node and/or User Equipment (UE), the IAB device receives a paging message triggered by a host node, the IAB device has data to be sent, and an RRC layer or an F1AP layer of the IAB node receives a connection recovery instruction of an upper layer; and the triggering module is used for triggering the wireless connection between the host node and the host node to recover.

With reference to the third aspect, in some possible implementations, the apparatus includes: an obtaining module, configured to obtain, according to a trigger condition that is satisfied, an access flag corresponding to the trigger condition; the checking module is used for carrying out access control checking according to the access mark; the triggering module is further configured to trigger, when the access control check passes, the IAB device to recover the wireless connection with the host node.

With reference to the third aspect, in some possible implementations, the access label is an access label associated with an IAB node.

With reference to the third aspect, in some possible implementations, the non-access stratum NAS of the IAB apparatus is configured to, according to a trigger condition that is met, obtain the access event corresponding to the trigger condition that is met, where the access event is an access event associated with an IAB node; the obtaining module is configured to obtain the access flag corresponding to the access event according to the access event.

With reference to the third aspect, in some possible implementations, the apparatus includes: a transceiver module, configured to send a wireless connection recovery request message to a host node, where the wireless connection recovery request message includes reason indication information, and the reason indication information corresponds to a satisfied trigger condition.

With reference to the third aspect, in some possible implementations, the apparatus includes: a transceiver module, configured to send IAB node indication information to a host node, where the IAB node indication information is used to indicate that the radio connection recovery is the radio connection recovery of an IAB node.

With reference to the third aspect, in some possible implementation manners, the satisfied trigger condition includes that the IAB apparatus receives access requests sent by child nodes, where the number of the access requests is greater than or equal to a threshold value, or the number of the child nodes is greater than or equal to the threshold value.

With reference to the third aspect, in some possible implementations, the apparatus includes: and the transceiver module is used for receiving the threshold value sent by the host node.

With reference to the third aspect, in some possible implementations, the IAB apparatus is a relay device or a device providing data backhaul, and the host node is a base station.

In a fourth aspect, an access network device is provided, including: a determination module configured to determine that any one or more of the following trigger conditions are satisfied: the access network equipment receives downlink data of non-activated UE, and the access network equipment receives a first paging message of idle UE; a transceiver module, configured to send a second paging message to the first access backhaul integrated IAB node, where the second paging message is used to indicate that the first IAB node triggers recovery of a wireless connection with a host node, and the host node is the access network device or a second host node.

With reference to the fourth aspect, in some possible implementation manners, the met trigger condition includes that the access network device receives downlink data of an inactive UE, and the determining module of the access network device is further configured to determine the first IAB node according to a radio access network RAN notification area of the inactive UE.

With reference to the fourth aspect, in some possible implementations, the triggering condition that is met includes that the access network device receives a first paging message of an idle UE, and the determining module of the access network device is further configured to determine the first IAB node according to a tracking area identity TAI list of the first paging message.

With reference to the fourth aspect, in some possible implementations, the transceiver module is further configured to receive a radio connection recovery request message sent by the first IAB node; the transceiver module is further configured to send a context request to a third host node, where the context request is used to request the third host node to send correspondence information between a distributed unit DU of the first IAB node and a mobile terminal MT of the first IAB node; the transceiver module is further configured to receive the correspondence information sent by the third host node.

With reference to the fourth aspect, in some possible implementation manners, the correspondence information includes: the DU identifier of the DU of the first IAB node and the inactive radio network temporary identifier I-RNTI of the MT of the first IAB node, and/or the new radio cell global identifier NR CGI of the DU of the first IAB node and the I-RNTI of the MT of the first IAB node.

With reference to the fourth aspect, in some possible implementation manners, the radio connection resumption request message carries an identifier of a first IAB node, where the identifier of the first IAB node includes an identifier of the third host node.

With reference to the fourth aspect, in some possible implementations, the first IAB node is a relay device or a device providing data backhaul, and the access network device is a base station.

In a fifth aspect, an access backhaul integrated IAB apparatus is provided, including: a processor configured to determine that any one or more of the following trigger conditions are met: the device receives an access request sent by a child node, wherein the child node comprises a second IAB node and/or User Equipment (UE), the device receives a paging message triggered by a host node, and the device has data to be sent; the RRC layer or F1AP layer of the device receives the connection recovery indication of the upper layer; and the communication interface is used for triggering the wireless connection recovery between the host node and the host node.

With reference to the fifth aspect, in a possible implementation manner, the processor is configured to obtain, according to a trigger condition that is met, an access flag corresponding to the trigger condition; the processor is used for carrying out access control verification according to the access mark; the processor is configured to trigger a radio connection restoration with the host node by the IAB apparatus when the access control check passes.

With reference to the fifth aspect, in one possible implementation, the access label is an access label associated with an IAB node.

With reference to the fifth aspect, in a possible implementation manner, the non-access stratum NAS of the IAB apparatus is configured to, according to a satisfied trigger condition, obtain the access event corresponding to the satisfied trigger condition, where the access event is an access event associated with an IAB node; the processor is configured to obtain the access flag corresponding to the access event according to the access event.

With reference to the fifth aspect, in a possible implementation manner, the communication interface is further configured to send a wireless connection recovery request message to the host node, where the wireless connection recovery request message includes cause indication information, and the cause indication information corresponds to the satisfied trigger condition.

With reference to the fifth aspect, in a possible implementation manner, the communication interface is further configured to send IAB node indication information to the host node, where the IAB node indication information is used to indicate that the radio connection recovery is radio connection recovery of an IAB node, and the IAB node indication information is carried in a radio connection recovery request message or a radio connection recovery completion message.

With reference to the fifth aspect, in a possible implementation manner, the satisfied trigger condition includes that the IAB apparatus receives access requests sent by child nodes, where the number of the access requests is greater than or equal to a threshold, or the number of the child nodes is greater than or equal to a threshold.

With reference to the fifth aspect, in a possible implementation manner, the communication interface is further configured to receive the threshold value sent by the host node.

With reference to the fifth aspect, in a possible implementation manner, the IAB apparatus is a relay device or a device providing data backhaul, and the host node is a base station.

In a sixth aspect, an access network device is provided that includes a processor and a communication interface. A processor configured to determine that any one or more of the following trigger conditions are met: the access network equipment receives downlink data of the non-activated UE, and receives a first paging message of the idle UE; a communication interface, configured to send a second paging message to the first access backhaul integrated IAB node, where the second paging message is used to indicate that the first IAB node triggers recovery of a wireless connection with a host node, and the host node is the access network device or a second host node.

With reference to the sixth aspect, in some possible implementations, the satisfied trigger condition includes that the access network device receives downlink data of the inactive UE, and the processor is further configured to determine the first IAB node according to a radio access network RAN notification area of the inactive UE.

With reference to the sixth aspect, in some possible implementations, the trigger condition that is met includes that the access network device receives a first paging message of an idle UE, and the processor is further configured to determine the first IAB node according to a tracking area identity TAI list of the first paging message.

With reference to the sixth aspect, in some possible implementations, the communication interface is further configured to receive a radio connection restoration request message sent by the first IAB node; the communication interface is further configured to send a context request to a third host node, where the context request is used to request the third host node to send correspondence information between the distributed unit DU of the first IAB node and the mobile terminal MT of the first IAB node; the communication interface is further configured to receive the correspondence information sent by the third host node.

With reference to the sixth aspect, in some possible implementations, the correspondence information includes: the DU identifier of the DU of the first IAB node and the inactive radio network temporary identifier I-RNTI of the MT of the first IAB node, and/or the new radio cell global identifier NR CGI of the DU of the first IAB node and the I-RNTI of the MT of the first IAB node.

With reference to the sixth aspect, in some possible implementation manners, the radio connection resumption request message carries an identifier of the first IAB node, and the identifier of the first IAB node includes an identifier of the third host node.

With reference to the sixth aspect, in some possible implementations, the first IAB node is a relay device or a device providing data backhaul, and the access network device is a base station or a donor base station.

In a seventh aspect, a wireless communication system is provided, comprising the first IAB node and the host node as described above.

In an eighth aspect, there is provided a wireless communication system comprising the first IAB node and the first host node as described above.

In a ninth aspect, a computer program storage medium is provided, characterized in that the computer program storage medium has program instructions which, when executed by a processor, cause the processor to perform the method of wireless communication as described in the foregoing.

In a tenth aspect, a chip system is provided, wherein the chip system comprises at least one processor, and when program instructions are executed in the at least one processor, the at least one processor is caused to execute the method for wireless communication described in the foregoing.

Drawings

Fig. 1 is an architecture diagram of an IAB system suitable for use in the solution of the present application.

Fig. 2 is a schematic diagram of the composition of an IAB node.

Fig. 3 (a) and (b) are examples of the protocol stack architecture of the intermediate IAB node.

Fig. 4 is an example of a user plane protocol stack architecture for a multi-hop IAB network.

Fig. 5 is an example of a control plane protocol stack architecture of a multi-hop IAB network.

Fig. 6 is a schematic diagram of a UE connected state.

Fig. 7 is a schematic diagram of an idle state of a UE.

Fig. 8 is a schematic diagram of a UE in a deactivated state.

Fig. 9 is a schematic diagram of an access network apparatus.

Fig. 10 is a schematic flow chart of an RRC recovery procedure.

Fig. 11 is a schematic flow chart of a method of wireless communication according to an embodiment of the present application.

Fig. 12 is a schematic flow chart of a method of wireless communication according to another embodiment of the present application.

Fig. 13 is a schematic flow chart of a method of wireless communication according to another embodiment of the present application.

Fig. 14 is a schematic flow chart of a method of wireless communication according to another embodiment of the present application.

Fig. 15 is a schematic flow chart of a method of wireless communication according to another embodiment of the present application.

Fig. 16 is a schematic flow chart of a method of wireless communication according to another embodiment of the present application.

Fig. 17 is a schematic structural diagram of an IAB apparatus according to another embodiment of the present application.

Fig. 18 is a schematic structural diagram of an access network device according to still another embodiment of the present application.

Fig. 19 is a schematic structural diagram of an IAB apparatus according to another embodiment of the present application.

Fig. 20 is a schematic structural diagram of an access network device according to still another embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The communication system mentioned in the embodiments of the present application includes but is not limited to: a narrowband internet of things (NB-IoT) system, a Wireless Local Access Network (WLAN) system, a Long Term Evolution (LTE) system, the 5th generation (5G) mobile communication system or a communication system after 5G, such as a New Radio (NR), a device-to-device (D2D) communication system, and the like.

Reference herein to a base station includes, but is not limited to: an evolved node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home evolved NodeB (HNB), a Base Band Unit (BBU), an evolved LTE (LTE) base station, an NR base station (neighbor B, gw), and the like.

Terminal devices include, but are not limited to: user Equipment (UE), a mobile station, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a terminal, a wireless communication device, a user agent, a station (station, ST) in a Wireless Local Access Network (WLAN), a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with wireless communication capability, a computing device, other processing devices connected to a wireless modem, a vehicle mounted device, a wearable device, a mobile station in a future 5G network, and a terminal device in a future evolved Public Land Mobile Network (PLMN) network, etc.

Wireless backhaul nodes (which may also be referred to as Integrated Access and Backhaul (IAB) nodes) are used to provide wireless backhaul (backhaul) services to nodes (e.g., terminals) accessing the wireless backhaul nodes. Wherein, the wireless backhaul service refers to a data and/or signaling backhaul service provided through a wireless backhaul link. The IAB node is a specific name of a relay node, and is not limited to the configuration of the present application, and may be one of the base station and the terminal device having a relay function, or may be in a separate device form. In a network including an IAB node (hereinafter referred to as an IAB network), the IAB node may provide a wireless access service for a terminal, and is connected to a donor base station (donor gNB) through a wireless backhaul link to transmit traffic data of a user.

For example, the IAB node may also be a Customer Premises Equipment (CPE), a home gateway (RG), or the like. In this case, the method provided by the embodiment of the present application may also be applied to a home access (home access) scenario.

Fig. 1 is an architecture diagram of an IAB system suitable for use in the solution of the present application. As shown in fig. 1, an IAB system at least includes a base station 100, one or more terminal equipments (terminal)101 served by the base station 100, one or more relay nodes (i.e., IAB nodes) 110, and one or more terminal equipments 111 served by the IAB nodes 110. The IAB node 110 is connected to the base station 100 through a wireless backhaul link 113. In general, the base station 100 is referred to as a donor base station. Alternatively, the donor base station is also referred to as a donor node or an IAB donor (IAB donor) in the present application. The IAB system may include one or more intermediate IAB nodes in addition to the above. For example, IAB node 120 and IAB node 130, IAB node 120 serves terminal device 121 over wireless link 122 and IAB node 130 serves terminal device 131 over wireless link 132.

The wireless links 102, 112, 122, 132, 113, 123, 133, 134 may be bidirectional links including uplink and downlink transmission links, and in particular, the wireless backhaul links 113, 123, 133, 134 may be used for the upper node to provide service for the lower node, such as the upper node 100 providing wireless backhaul service for the lower node 110. It should be appreciated that the uplink and downlink of the backhaul link may be separate, i.e., the uplink and downlink are not transmitted through the same node.

The host base station may be an access network element having a complete base station function, or may be in a form in which a centralized unit (CU for short) and a distributed unit (DU for short) are separated, that is, the host node is composed of the centralized unit of the host base station and the distributed unit of the host base station. Herein, a centralized unit of a host node is also referred to as an IAB donor CU (also referred to as a donor CU, or directly as a CU). The distributed unit of the home node is also called an IAB donor DU (or donor DU). Wherein the donor CU may also be in a separate configuration of a Control Plane (CP) (abbreviated CU-CP herein) and a User Plane (UP) (abbreviated CU-UP herein). For example, a CU may consist of one CU-CP and one or more CU-UP.

In the embodiment of the application and in the drawings, the method provided by the embodiment of the application is exemplified by the case that the host node is composed of a Donor-CU and a Donor-DU.

The concepts involved in the IAB system are exemplarily described below with reference to fig. 1.

1. The basic concept.

And link: refers to a path between two adjacent nodes in a path.

And accessing a link: and the link between the terminal equipment and the base station, or between the terminal equipment and the IAB node, or between the terminal equipment and the host DU. Alternatively, the access link may comprise a radio link used by an IAB node to communicate with its parent node in the role of a normal end device. When the IAB node is in the role of a common terminal device, the back-transmission service is not provided for any child node. The access link includes an uplink access link and a downlink access link. In the present application, the access link of the terminal device is a wireless link, so the access link may also be referred to as a wireless access link.

A return link: the IAB node is used as a link between the wireless backhaul node and a parent node. When the IAB node is used as a wireless backhaul node, the IAB node provides wireless backhaul service for the child node. The backhaul links include an uplink backhaul link, and a downlink backhaul link. In the present application, the backhaul link between the IAB node and the parent node is a wireless link, and therefore the backhaul link may also be referred to as a wireless backhaul link.

Parent node and child node: each IAB node treats neighboring nodes for which wireless access service and/or wireless backhaul service is provided as parent nodes (parent nodes). Accordingly, each IAB node may be considered a child node (child node) of its parent node.

Alternatively, a child node may also be referred to as a subordinate node, and a parent node may also be referred to as an upper node.

Last hop node of the node: refers to the node in the path containing the node that last received a packet before the node. It is to be understood that the node's previous hop node may include a node's previous hop node in uplink transmission and a node's previous hop node in downlink transmission.

Next hop node of node: refers to the node in the path containing the node that first receives a packet after the node. It is to be understood that the next hop node of a node may include the next hop node of the node in uplink transmission and the next hop node of the node in downlink transmission.

Ingress link of a node: refers to a link between the node and a previous hop node of the node, and may also be referred to as a previous hop link of the node. It will be appreciated that the ingress link of a node may include the ingress link of the node in uplink transmission and the ingress link of the node in downlink transmission.

Egress link of node: refers to a link between the node and a next hop node of the node, and may also be referred to as a next hop link of the node. It will be appreciated that the egress links of a node may include the egress link of the node in uplink and the egress link of the node in downlink.

Accessing the IAB node: refers to an IAB node to which a terminal accesses, or an IAB node providing access service for a terminal device.

Intermediate IAB node: refers to an IAB node that provides wireless backhaul service to other IAB nodes (e.g., an access IAB node or other intermediate IAB nodes), or an intermediate IAB node refers to an IAB node between an access IAB node and a home node.

2. Composition of IAB nodes.

The IAB node may have a Mobile Terminal (MT) part and a DU part. The DU part of the IAB node has part of the functionality of the gNB for serving its child nodes (which may be terminals or another IAB node). The MT part of the IAB node is similar to the UE for providing data backhaul. An IAB node communicates with its parent node using the MT part and communicates with its child nodes using the DU part. An IAB node may establish backhaul connections with at least one parent node of the IAB node via the MT part. The DU part of one IAB node may provide access services for the MT part of a terminal or other IAB node. A two-hop Backhaul (BH) link is illustrated below in conjunction with fig. 2.

Fig. 2 is a schematic diagram of the composition of an IAB node. The UE is connected to the host node through IAB node 2 and IAB node 1. Illustratively, IAB node 1 and IAB node 2 each include a DU portion and an MT portion. The DU part of IAB node 2 provides access services for the UE. The DU part of IAB node 1 provides access services to the MT part of IAB node 2. The DU portion of the home node functions similarly to the DU portion of the IAB node to provide access services to the MT portion of the IAB node 1. The CU part of the donor node is used to control and manage all the IAB nodes and UEs below it. The CU part of the host node is connected to a Core Network (CN) via an NG interface. The core network may also be referred to as a 5G core network (5 GC) or a new generation core Network (NGC).

For ease of understanding, the protocol stack of the IAB network needs to be described as well. The protocol stack of the IAB network includes a user plane protocol stack and a control plane protocol stack.

3. And accessing the protocol stack architecture of the IAB node, the intermediate IAB node, the Donor-DU, the Donor-CU and the terminal equipment.

The intermediate IAB nodes have the same protocol stacks in the user plane and the control plane. Fig. 3 (a) and (b) are examples of the protocol stack architecture of the intermediate IAB node. Illustratively, the MT part and the DU part of the intermediate IAB node may not share an adaptation (adapt) layer or adaptation layer entity, as shown in fig. 3 (a). In the case of IAB, the adaptation layer may also be referred to as a Backhaul Adaptation Protocol (BAP) layer. The MT part and the DU part of the intermediate IAB node may also share an adaptation layer or adaptation layer entity, as shown in fig. 3 (b).

The protocol stacks for the access IAB node are different in the user plane and the control plane, see IAB node 2 in fig. 4 and fig. 5, respectively.

Referring to fig. 4, fig. 4 is an example of a user plane protocol stack architecture of a multi-hop IAB network. As shown in fig. 4, in the protocol architecture shown in fig. 4, the meaning of each protocol layer is: a Packet Data Convergence Protocol (PDCP) layer, a general packet radio service tunneling protocol user plane (GTP-U) layer, a User Datagram Protocol (UDP) layer, an Internet Protocol (IP) layer, an L2 layer (layer 2), an L1 layer (layer 1), a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, a Physical (PHY) layer, and a Radio Resource Control (RRC) layer. Wherein the L2 layer is a link layer. Illustratively, the L2 layer may be the data link layer in the Open Systems Interconnection (OSI) reference model. The L1 layer may be a physical layer. Illustratively, the L1 layer may be the physical layer in the OSI reference model.

In order to meet the service quality requirements of different types of services of the terminal device, one or more Radio Bearers (RBs) are introduced into the wireless network, and the radio bearers include a Data Radio Bearer (DRB) and a Signaling Radio Bearer (SRB) for transmitting different types of service data (including control plane signaling and user plane data) between the UE and the base station. In an IAB network, an RB can be considered as a logical channel for transmitting data between a UE and a donor node.

Illustratively, each protocol layer is configured with its corresponding protocol layer entities, such as PDCP entity, RLC entity, MAC entity, etc. In uplink transmission, a data packet (e.g., an IP data packet) of the UE is transmitted to a PHY layer of an access backhaul node (e.g., IAB node 2 shown in fig. 4) after being processed by a PDCP layer and then sequentially passing through an RLC layer, a MAC layer and the PHY layer.

As described above, in an IAB network, an IAB node may contain a DU part and an MT part. When the IAB node is acting as a wireless backhaul node, the MT part of the IAB node performs data forwarding on the backhaul link without requiring the terminal device's complete protocol stack on the wireless access link. For example, IAB node 2 shown in fig. 4 for IAB node 1, IAB node 2 is a child node of IAB node 1. When IAB node 2 sends a packet from UE to IAB node 1, the MT of IAB node 2 does not need PDCP layer, and the packet is forwarded under adaptation layer (adapt layer). Therefore, in fig. 4, when the IAB node is used as the wireless backhaul node to send a data packet to its parent node, only the protocol layers below the adaptation layer are involved, which is applicable to all IAB nodes and is not described again.

When the IAB node plays the role of a wireless terminal, the protocol stack of the communication link between the IAB node and the parent node is the same as the protocol stack of the wireless access link between the UE and the access IAB node, and the protocol stack between the IAB node and the donor CU is the same as the protocol stack between the UE and the donor CU.

In addition, the user plane (F1-U) protocol stack of the F1 interface between the hosting CU and the access IAB node (e.g., IAB node 2 in fig. 4) is also shown in fig. 4. The GTP-U tunnel established by the F1 interface through the GTP-U protocol layer is in one-to-one correspondence with the data radio bearer DRB of the UE. In other words, each radio bearer of a UE has a GTP tunnel corresponding to it.

Referring to fig. 5, fig. 5 is an example of a control plane protocol stack architecture of the multi-hop IAB network. The description of the protocol layers in fig. 4 is also applicable in fig. 5, but there are some differences. For example, in fig. 5, the F1 interface between the access IAB node and the host CU uses the F1 control plane (F1-C) protocol stack, which includes: f1application protocol (F1application protocol, F1AP) layer, Stream Control Transmission Protocol (SCTP) layer.

It should be noted that fig. 4 and 5 respectively show an example of an end-to-end user plane and a control plane protocol stack architecture for transmitting data traffic of a UE in an IAB network. Alternatively, the protocol stack architecture may have other possibilities. For example, if the F1 interface between the IAB2 and the host CU introduces a protocol layer for security protection, the protocol stack architecture will change.

In addition, if the host node is a functionally complete entity, the IAB donor may reserve the protocol stack of the donor DU and the donor CU for the external node interface, and a protocol layer on the internal interface between the donor DU and the donor CU is not necessary. Similarly, the protocol stack of the IAB node, for the outside, may not distinguish between the DU part and the MT part, and only show the protocol stack of the interface to the external node in a unified way.

In addition, no matter the protocol stack architecture of the control plane or the protocol stack architecture of the user plane, if the donor DU is a proxy node of the F1 interface between the donor CU and the IAB node, the user plane protocol stack architecture of the donor DU facing the access IAB node may include, above the IP layer, a UDP layer and a GTP-U layer respectively equivalent to the UDP layer and the GTP-U layer in the protocol stack architecture of the DU part in the access IAB node, and may further include an IPsec layer equivalent to the DU part of the access IAB node; in the control plane protocol stack architecture facing the access IAB node in the Donor-DU, above the IP layer, the control plane protocol stack architecture may include an SCTP layer and an F1AP layer that are respectively equivalent to the SCTP layer and the F1AP layer in the protocol stack architecture of the DU part in the access IAB node, and may further include an IPsec layer or a DTLS layer that is equivalent to the DU part of the access IAB node.

According to the control plane protocol stack, IAB node 2 may send the UE's RRC message to the IAB donor CU in an F1AP message (e.g., a UE-associated F1AP message, i.e., UE-associated F1 AP).

Fig. 4 and 5 also relate to the F1 interface.

4. Protocol layer of F1 interface and F1 interface

Illustratively, the F1 interface refers to the logical interface between the DU part of the IAB node and the home node (Donor-CU), or alternatively, to the logical interface between the home node Donor-CU and the Donor-DU. The F1 interface between the DU part of the IAB node and the home node (donor-CU) may also be referred to as F1 interface, supporting the user plane and the control plane. The protocol layer of the F1 interface refers to the communication protocol layer on the F1 interface.

The PHY, MAC and RLC layers of the UE peer are located on the IAB node 2DU, i.e., the Access IAB node DU, while the PDCP, SDAP and RRC layers of the UE peer are located on the IAB node CU.

Compared with the LTE system in which the UE has only two states, namely idle mode and connected mode, the UE in NR introduces a new state, namely inactive mode.

Fig. 6 is a schematic diagram of a UE in a connected state.

RRC connection between UE and gNB, and NG connection between gNB and NGC exist, and the gNB retains context of UE.

Fig. 7 is a diagram illustrating the UE in an idle state.

The RRC connection between the UE and the gNB, and the NG connection between the gNB and the NGC are released, and the gNB deletes the context of the UE.

Fig. 8 is a schematic diagram of a UE in an inactive state.

The inactive state is a state between the idle state and the connected state, namely: the RRC connection between the UE and the gNB is released, but the NG connection between the gNB and the NGC remains, and the gNB retains the context of the UE.

Fig. 9 is a schematic diagram of the gNB in NR.

In the NR, the gNB may adopt a CU-DU separation architecture, that is, one gNB is composed of one gNB-CU and one or more gNB-DUs, where the gNB-CU and the gNB-DU are connected through an F1 interface, and the gNB-CU and the core network NGC are connected through an NG interface.

And the UE accesses the gNB-CU through the gNB-DU, namely the corresponding PHY/MAC/RLC layer function of the UE is positioned on the gNB-DU, and the peer PDCP/SDAP/RRC layer function of the UE is positioned on the gNB-CU.

In the connected state, both the gNB-CU and the gNB-DU store the context of the UE. In the inactive state, the gNB-CU reserves the UE context, and the gNB-DU can delete the UE context.

Through the UE non-activation state, the power consumption of the user equipment can be effectively reduced, and simultaneously, once the UE needs to enter the connection state from the non-activation state, the RRC connection can be quickly recovered, and the RRC recovery time delay is reduced.

Fig. 10 is a schematic flow diagram of RRC recovery between a UE and a gNB.

In NR, the triggering conditions for the UE in the inactive state to perform the RRC recovery procedure include the following three conditions:

condition 1: triggered by the upper layer (upper layer) of the UE, for example: when Uplink (UL) data is to be transmitted, the UE needs to enter a connected state from an inactive state, which triggers an RRC recovery procedure.

Condition 2: triggered by the RRC layer of the UE, for example: the UE needs to perform a RAN-based notification area (RNA) update (update). The RAN-based notification area may also be referred to as a RAN notification area. Illustratively, the UE in the inactive state may periodically perform RNA update. Alternatively, the UE in the inactive state discovers an RNA update triggered by its movement outside the RAN notification area configured by the network, thereby triggering the RRC recovery procedure. RNA update, i.e. the host CU reconfigures a new RAN notification area for the UE. The RAN notification area may be determined based on RAN area code (RAN area code) information or may be determined based on cell information (e.g., NR CGI).

Condition 3: the UE receives a paging message based on the RAN notification area. For example: when the called service exists in the inactive state UE, the UE needs to enter the connected state from the inactive state, and an RRC recovery procedure is triggered.

That is, as long as any one or more of the three triggering conditions is/are satisfied, the inactive UE triggers the RRC recovery procedure to perform RRC recovery through the gNB DU and the gNB CU.

In step S1001, the UE transmits a preamble sequence to the gNB-DU. The preamble sequence is a physical signal transmitted by the UE on a Physical Random Access Channel (PRACH). When the gmb receives the preamble sequence on the PRACH, the gmb considers that there is UE access.

In step S1002, the gNB-DU sends a Random Access Response (RAR) message to the UE, where the RAR message carries a radio network temporary identity (C-RNTI) allocated by the gNB-DU to the UE in the access cell. The C-RNTI is the only identification of the connected UE in the access cell.

In step S1003, the UE transmits an RRC recovery Request (RRC Resume Request) message to the gNB-DU for requesting recovery of the RRC connection.

In step S1004, the gNB-DU forwards the RRC Resume Request message to the gNB-CU. Illustratively, the gNB-DU encapsulates the RRC Resume Request Message in an Initial UL RRC Message Transfer (Initial UL RRC Message Transfer) Message for transmission to the gNB-CU. Optionally, the Initial UL RRC Message Transfer Message may also carry a Cell Global Identifier (CGI) of an NR cell of a gNB-DU accessed by the UE, and an identifier C-RNTI of the UE in the cell.

In step S1005, the gNB-CU sends a UE context setup request message to the gNB-DU for requesting the gNB-DU to set up the context of the UE.

In step S1006, after the gNB-DU establishes the UE context, the gNB-DU sends a UE context establishment response message to the gNB-CU, where the UE context establishment response message is used by the gNB-DU to confirm that the UE context establishment is complete.

In step S1007, the gNB-CU generates an RRC recovery Message, and this RRC recovery Message is encapsulated in a DL RRC Message Transfer (DL RRC Message Transfer) Message and transmitted to the gNB-DU.

In step S1008, the gNB-DU receives the DL RRC Message Transfer Message, extracts an RRC recovery Message from the Message, and transmits the Message to the UE.

In step S1009, the UE transmits an RRC resume complete message to the gNB-DU.

In step S1010, the gNB-DU transmits an RRC recovery complete Message encapsulated in a UL RRC Message Transfer (UL RRC Message Transfer) Message to the gNB-CU.

In an IAB scenario, when the IAB node has an energy saving requirement, or when the UEs served by the IAB node are all in an idle state or an inactive state, or when the number of UEs in the coverage area of the IAB node or the amount of data for serving is lower than a threshold, the IAB node may disconnect/release the RRC connection with the host node in order to reduce the power consumption of the IAB node, that is: the IAB node operates in an inactive state. The threshold may be preset by the IAB node or configured by the host node as an IAB node.

Fig. 11 is a schematic flow chart of a communication method provided in an embodiment of the present application.

In step S1101, the first IAB node determines that the trigger condition is satisfied. The trigger condition may include any one or more of the following:

the first IAB node receives an access request sent by a child node, wherein the child node comprises a second IAB node and/or User Equipment (UE),

the first IAB node receives a paging message triggered by the home node,

the first IAB node has data to send,

the RRC layer or F1AP layer of the first IAB node receives a connection restoration indication of an upper layer, where the connection restoration indication is used to instruct the first IAB node to restore the wireless connection with the host node.

The first IAB node is a relay device or a device providing data backhaul, and the host node is a base station.

And when the child node of the first IAB node has data to be sent, restoring the wireless connection with the host node. The child node of the first IAB node sends an access request to the first IAB node, where the access request may be one or more of a preamble sequence, an RRC setup request message, an RRC recovery request message, an F1 connection recovery request message, and other access requests.

The satisfied trigger request may include the first IAB node receiving an access request sent by a child node. The first IAB node may be provided with a threshold value for the number of child nodes or the number of access requests. Reaching or exceeding the threshold value, step S1102 is performed. That is, the first IAB node may perform step S1102 when the number of received access requests is greater than or equal to the threshold value, or the first IAB node may perform step S1102 when the number of child nodes corresponding to the received access requests is greater than or equal to the threshold value.

The threshold value may be preset by the first IAB node or may be configured by the host node. The first IAB node may send the threshold value to the first IAB node via a connection release message when the first IAB node disconnects the RRC connection with the host node or when the first IAB node enters an inactive state from a connected state. The donor node may configure a threshold value for the first IAB node according to a load capability of the donor node, a load capability of the first IAB node, and the like.

In step S1102, the first IAB node triggers the restoration of the radio connection with the host node. The radio connection may be, for example, RRC connection recovery, F1 connection recovery, or the like.

Triggering the restoration of the wireless connection with the host node may also be understood as sending a preamble sequence or a wireless connection restoration request to the host node.

The first IAB node may trigger a radio connection restoration with the host node in case a trigger condition is met. Or, the first IAB node performs access control check when the trigger condition is satisfied, and the first IAB node triggers the recovery of the radio connection with the host node when the access control check is passed.

Prior to step S1102, the first IAB node may perform an access control check to determine whether the current access attempt is allowed.

The first IAB node may obtain an access flag corresponding to the trigger condition according to the trigger condition being satisfied. And the first IAB node carries out access control verification according to the access mark. The procedure of the access control check can be seen in the description of fig. 15.

The access flags obtained by the first IAB node may be the same or different for different trigger conditions. The first IAB node may maintain a correspondence between the trigger condition and the access flag. The first IAB node may determine the access label according to the correspondence. Alternatively, the first IAB node may select the access flag according to other conditions, where the access flag selected by the first IAB node is the access flag corresponding to the trigger condition.

An access label different from that of the UE may be defined for the IAB node. The access flag obtained by the first IAB node may be an access flag associated with the IAB node, that is, an access flag defined for the IAB node, or an access flag corresponding to the IAB node.

The Access label may be an Access Category (Access Category) and/or an Access Identity (Access Identity). The access category defined for the IAB node may be a reserved access category, or other access category. The access category defined for the IAB node may be a reserved access identity, or other access identity.

A non-access stratum (NAS) of the first IAB node may be used to select the access label based on the trigger condition. The RRC layer of the first IAB node may also select the access flag based on a triggering condition.

According to the satisfied trigger condition, the NAS layer of the first IAB node may obtain an access event corresponding to the satisfied trigger condition. The first IAB node may obtain an access flag corresponding to the access event according to the access event.

Different access events may be defined for the IAB node than for the UE. The access event determined by the NAS layer of the first IAB node may be an access event associated with the IAB node, that is, an access event defined for the IAB node, or an access event corresponding to the IAB node.

The first IAB node triggers the wireless connection between the first IAB node and the host node to be recovered, the first IAB node sends a wireless connection recovery request message to the host node, the wireless connection recovery request message comprises reason indication information, and the reason indication information corresponds to the satisfied triggering condition. One kind of cause indication information may indicate one kind of trigger condition, or one kind of cause indication information may correspond to a plurality of kinds of trigger conditions. Namely: the trigger condition may correspond to a cause value in the cause indication information one-to-one, and one cause value may also correspond to a plurality of trigger conditions.

The host node may perform different processing according to different trigger conditions. For example, the host node may determine whether to resume the wireless connection with the first IAB node based on load conditions, etc.

The first IAB node may send IAB node indication information to the host node, which may be used to indicate that the radio connection recovery is a radio connection recovery of the IAB node. Alternatively, the AB node indication information may be used to indicate that radio connection restoration is IAB node triggered. The IAB node indication information may be carried in an RRC recovery request message or a radio connection recovery complete message, or may be carried in other messages. The donor node may resume for the IAB node or for the UE to do different processing depending on the radio connection. The first IAB node is an IAB node.

The first IAB node may be an inactive IAB node. The host node holds the context of the first IAB node. The sub-nodes of the IAB of the first IAB node may include any one or more of an idle state UE, an inactive state UE, and an inactive state IAB node.

Through steps S1101 to S1102, the first IAB node is able to resume the wireless connection with the host node. The power consumption is reduced while the communication requirement is met.

The following description will be made by taking the case of the radio connection recovery as the RRC connection recovery. The radio connection resumption request may be an RRC resumption request, and the radio connection resumption completion message may be an RRC resumption completion message.

Fig. 12 is a schematic flow chart of a communication method provided in an embodiment of the present application.

The IAB node comprises an IAB-DU and an IAB-MT. The IAB nodes in the figure may be access IAB nodes or intermediate IAB nodes.

The host node comprises a host DU and a host CU. The IAB node is in the inactive state, which means that the IAB MT is in the inactive state and the IAB DU is in the inactive state. No RRC connection exists between the IAB MT in the inactive state and the host node. The host CU holds the context of the inactive IAB node. The context of the inactive IAB node may include one or more of a security algorithm and a key used by the IAB MT over the air interface, air interface configuration of the IAB MT, an identity of the IAB DU, a cell identity of the IAB DU, and a correspondence between the IAB MT and the IAB DU. The correspondence between the IAB MT and the IAB DU may be, for example, a correspondence between an inactive-radio network temporary identifier (I-RNTI) of the IAB MT and a DU identifier (DU identification) of the IAB DU, or a correspondence between an I-RNTI of the IAB MT and a CGI of an NR of an IAB DU cell.

The I-RNTI is used for identifying an IAB MT in an inactive state, and can be a short identification of 24 bits or a long identification of 40 bits. When the IAB node enters an inactive state from a connected state, the host CU configures the I-RNTI (long identification or short identification) for the IAB node. It should be understood that in the inactive IAB node, both IAB-DU and IAB-MT are inactive. Illustratively, the IAB-DU is in an inactive state, which means that the IAB DU operates in a Discontinuous Transmission (DTX) state and is configured using a long-period Measurement Timing Configuration (MTC). That is, to save power, the IAB DU transmits only a System Information Block (SIB) 1 and a Synchronization Signal Block (SSB) for the idle UE or the inactive UE to access or other IAB nodes in the inactive state.

In step S1201, the child node sends a request to the IAB-DU, for example: a preamble sequence is transmitted. The child node may be an inactive or idle UE, or may be another IAB node in an inactive state.

In step S1202, the IAB-DU sends a RAR message to the child node. The RAR message may carry the C-RNTI allocated by the IAB-DU to the child node.

If the child node is an idle UE, the child node sends an RRC establishment request to the IAB-DU at step S1203. If the child node is an inactive UE or another IAB node, the child node sends an RRC recovery request to the IAB-DU at step S1203.

In step S1204, the IAB-DU transmits, to the IAB-MT, instruction information for instructing the IAB MT to resume the RRC connection with the host CU. This indication information may be referred to as a connection resume indication.

Step S1204 may be performed after step S1201. And after receiving the preamble sequence sent by the child node, the IAB-DU sends indication information to the IAB-MT, triggers the IAB-MT to initiate an RRC recovery flow to the host CU, and recovers the RRC connection between the IAB-MT and the host CU as soon as possible.

Alternatively, step S1204 may be performed after step S1203. And after receiving the RRC establishment request sent by the child node, the IAB-DU sends indication information to the IAB-MT, triggers the IAB-MT to initiate an RRC recovery flow to the host CU, and recovers the RRC connection between the IAB-MT and the host CU as soon as possible.

As an alternative, the IAB-DU sends the indication information to the IAB-MT after receiving the RRC setup request, RRC recovery request, or preamble sequence sent by the N child nodes. N is a positive integer. N may be preset by the IAB-DU node or may be configured by the host node. The host CU may configure N to the IAB-DU when the IAB node enters the inactive state. For example, the donor node may flexibly configure N according to the load condition of the donor node when the IAB node enters the unconnected state, and the like.

In step S1205, the IAB-MT starts the RRC recovery procedure after receiving the indication information.

When the IAB-DU has uplink data to be transmitted, the indication information may also be transmitted to the IAB-MT. For example, when the IAB-DU needs to send a service to the OAM server, the IAB-DU sends an indication message to the IAB-MT, and triggers the IAB-MT to initiate an RRC recovery procedure to the host CU.

Fig. 13 is a schematic flow chart of a communication method provided in an embodiment of the present application.

In step S1601, the first host node determines that the trigger condition is satisfied.

The triggering condition comprises that the first host node receives downlink data of the non-activated UE, and/or the first host node receives a first paging message of the idle UE.

The trigger condition may also include the first host node determining to resume the wireless connection with the first IAB node. For example, due to limitations in the processing power of the first sink node, the first sink node determines to resume the wireless connection with the first IAB node, which may be an RRC connection, or an F1 connection, or the like.

The first host node may determine whether an IAB node in an inactive state exists in a paging area of the UE before paging the UE. If so, the first host node may first restore the wireless connection with the IAB node.

And under the condition that the first host node receives downlink data of the non-activated UE, the first host node determines the first IAB node according to the stored radio access network RAN notification area of the non-activated UE.

The first host node maintains a RAN notification area with inactive UEs. When the first host node receives downlink data of the inactive UE, the first host node may determine one or more IAB nodes corresponding to a RAN notification area according to the RAN notification area of the inactive UE. If one or more IAB nodes corresponding to the RAN notification area comprise an IAB node with disconnected wireless connection with the host CU, namely the IAB node in an inactive state, the first host node determines the IAB node in the inactive state as the first IAB node.

In a case that a first host node receives a first paging message of an idle UE, the first host node may determine a first IAB node according to a Tracking Area Identity (TAI) list (list) carried by the first paging message.

The core network stores a TAI list configured for the idle-state UE, and can determine the cell included in the paging range of the idle-state UE according to the TAI list. After receiving the downlink data of the idle-state UE, the core network sends a first paging message to a host node corresponding to a cell in a paging area determined by the TAI list. The first paging message includes a TAI list. The first host node may determine, according to the TAI list, one or more IAB nodes corresponding to cells in the paging area of the idle-state UE. If one or more IAB nodes corresponding to the cell in the paging area of the idle-state UE include an IAB node with a disconnected wireless connection with the host CU, that is, an inactive IAB node, the first host node determines the inactive IAB node as the first IAB node.

In step S1602, the first host node sends a second paging message to the first IAB node, where the second paging message is used to indicate that the first IAB node triggers the recovery of the wireless connection with the host node. And after receiving the second paging message, the first IAB node triggers to recover the wireless connection with the host node. The host node performing the wireless connection recovery may be the first host node, or may be another host node.

After the first host node instructs the first IAB node to enter the inactive state from the connected state, the host node to which the first IAB node accesses may change due to mobility of the first IAB node or cell selection when the IAB node needs to return to the connected state from the inactive state.

And the first host node receives a wireless connection recovery request message sent by the first IAB node, namely the first host node is a target host node of the first IAB node.

If the first host node stores the corresponding relationship between the DU of the first IAB node and the MT of the first IAB, that is, the source host node of the first IAB node is the same as the target host node. The first host node may determine the MT of the first IAB based on the DU cell included in the paging area according to the correspondence.

If the first host node does not store the corresponding relationship between the DU of the first IAB node and the MT of the first IAB, that is, the source host node and the target host node of the first IAB node are different. The third host node is a source host node of the first IAB node. The first host node may send a context request to the third host node. The context request is used to request the third host node to send the correspondence information between the distributed unit DU of the first IAB node and the mobile terminal MT of the first IAB node. And the first host node receives the corresponding relation information sent by the third host node.

The correspondence information may include a DU identity of a DU of the first IAB node and an inactive radio network temporary identity I-RNTI of the MT of the first IAB node.

The correspondence information may also include a new radio cell global identity NR CGI of the first IAB node DU and an I-RNTI of the MT of the first IAB node.

The first host node may determine the third host node according to the wireless connection restoration request message. The radio connection restoration request message carries an identifier of the first IAB node, where the identifier of the first IAB node includes an identifier of the third host node.

Fig. 15 is a schematic flow chart of a communication method according to an embodiment of the present application.

When the inactive state UE or the idle state UE in the coverage of the inactive state IAB node has downlink data to be transmitted (i.e., there is a called service), the inactive state IAB node may also be triggered to initiate an RRC recovery procedure to the host node.

In step S1301, the host CU receives DL data or a paging message sent by a network element of the core network.

For an inactive UE, the host CU receives DL data of the UE sent by a network element of the core network. For idle UE, the host CU receives a paging message sent by a network element of the core network.

In step S1302, the donor CU determines an IAB node in an inactive state.

For the inactive UE, the host CU first determines an inactive IAB node in a RAN notification area of the UE according to RAN notification area information configured by the inactive UE. For idle UE, the host CU first determines an inactive IAB node in a CN paging area according to a Tracking Area Identity (TAI) list (list) carried in a received core network paging message.

In step S1303, the host CU sends a paging message for the IAB-MT.

The host CU pages the inactive IAB node first. And after the IAB node is changed from the inactive state to the connected state and the RRC connection between the IAB node and the host CU is recovered, the host CU initiates paging to the UE through the connected-state IAB node.

DL data needs to be sent to idle UE or inactive UE in the cell covered by the IAB DU, and when the DL data reaches the host CU or the core network element, the host CU needs to wake up the inactive IAB MT in the paging area corresponding to the idle UE or the RAN notification area of the inactive UE before paging the UE.

For idle UE, when there is DL data arriving at the core network element, the core network element initiates core network paging (CN paging). And the core network element sends a paging message to all gNBs including the host CU in a paging area of the idle-state UE. When the inactive state IAB node exists in the paging area of the idle state UE, the host CU needs to wake up the inactive state IAB node in the paging area before paging the idle state UE, that is, to recover the RRC connection between the host CU and the IAB MT and recover the F1 connection between the host CU and the IAB DU, and then the host CU sends an F1 paging message to the IAB DU to request the IAB DU to page the UE.

Illustratively, a paging message sent by a core network element carries a Tracking Area Identity (TAI) list, and according to the TAI list, all cell information included in a tracking area may be determined. The cell information may be, for example, a cell identity, such as NR CGI.

With the NR CGI, the host node can determine the IAB DU. That is, the host CU may determine cell information (e.g., cell identifier NR CGI) in the paging area according to the TAI list carried in the received core network paging message, and then determine the corresponding IAB MT according to the cell information. For example, the host CU may determine the corresponding IAB DU from the cell information, and determine the IAB MT according to the correspondence between the IAB DU and the IAB MT. Illustratively, an IAB DU contains one or more cells.

When the IAB DU and the host CU establish the F1 connection, the host CU may know and store the relationship between the IAB DU and the IAB DU cell, for example: relationship of identity DU ID of IAB DU and identity NR CGI of IAB DU cell. Namely: the host CU can determine cell identifiers NR CGI of all IAB DUs in the paging area according to the TAI list, and then determine all inactive IAB MTs in the paging area according to the corresponding relation between the cell identifiers NR CGI of the IAB DUs and the I-RNTI of the IAB MT identifiers. Or, the host CU may determine cell identities NR CGI of all IAB DUs in the paging area according to the TAI list, then determine all IAB DUs in the paging area according to a correspondence between an identity DU ID of the IAB DU and the cell identity NR CGI of the IAB DU, and finally determine all inactive IAB MTs in the paging area according to a correspondence between an identity DU ID of the IAB DU and an identity I-RNTI of the IAB MT.

For the inactive UE, when DL data arrives at the core network element, the core network element may further send the DL data to the host CU because a connection exists between the core network element and the host CU for the inactive UE. The host CU determines cell information (such as cell identification NR CGI) in the RAN notification area according to RAN notification area information configured for the UE in the non-activated state, and then determines a corresponding IAB MT according to the cell information, or determines a related IAB DU according to the cell information, and finally determines the IAB MT according to the corresponding relation between the IAB DU and the IAB MT. Illustratively, the IAB DU includes one or more cells, and when the IAB DU and the host CU establish the F1 connection, the host CU may learn and store the relationship between the IAB DU and the IAB DU cells, for example: relationship of identity DU ID of IAB DU and identity NR CGI of IAB DU cell. Namely: the host CU determines cell identifiers NR CGI of all IAB DUs in the area according to the RAN notification area configured for the UE in the non-activated state, and then determines all IAB MTs in the non-activated state in the RAN notification area according to the corresponding relation between the cell identifiers NR CGI of the IAB DUs and the I-RNTI of the IAB MT identifiers. Or, the host CU determines cell identities NR CGI of all IAB DUs in the area according to the RAN notification area configured for the inactive UE, determines all IAB DUs in the area according to a correspondence between an identity DU ID of the IAB DU and the cell identity NR CGI of the IAB DU, and determines all inactive IAB MTs in the RAN notification area according to a correspondence between an identity DU ID of the IAB DU and an identity I-RNTI of the IAB MT.

In step S1304, the IAB node performs an RRC recovery procedure with the host CU.

In step S1305, the F1 interface resumes.

After the RRC connection is restored, a fast F1 interface recovery procedure between the IAB-DU and the host CU will be triggered. For example: the host CU stores the cell information of the IAB DU, and once the host CU knows that the RRC connection with the IAB MT is restored, the host CU triggers sending of an F1 interface restoration message to the IAB DU, where the message carries activation indication information of the IAB DU cell, that is: indicating which IAB DU cells are activated.

In step S1306, the host CU transmits a paging message to the IAB DU. For the inactive UE, the host CU sends a paging message to the IAB-DU of the IAB node corresponding to all cells in the area notified by the RAN configured by the UE to find the UE. For idle state UE, host CU sends paging message to IAB-DU of IAB node corresponding to all cells in paging area configured by UE.

In step S1307, the IAB-DU generates a paging message of the RRC layer according to the paging message received from the F1 interface and transmits the paging message.

For idle state UE, an Authentication Management Function (AMF) network element of the core network generates an NG paging message and sends the NG paging message to the host CU through an NG interface. Then the host CU generates F1 paging message according to the received NG paging message, and sends F1 paging message to IAB DU through F1 interface. And the IAB DU generates a final paging message of the RRC layer according to the F1 paging message and sends the final paging message to the UE.

For the inactive UE, the donor CU generates F1 paging message, and sends F1 paging message to the IAB DU through F1 interface. And generating a paging message of an RRC layer by the IAB DU according to the F1 paging message and sending the paging message to the UE.

In some embodiments, the DL data may also be data of the IAB node, that is, the data needs to be sent to the IAB node, where the data may be, for example, network management service data (e.g., data sent by an OAM server to an IAB DU), and the OAM server sends the DL data to the host CU, and the host CU determines that the IAB node is in an inactive state according to the context of the IAB node, and then the host CU sends a RAN paging message to trigger the inactive IAB node to execute an RRC recovery procedure. The host CU may send a RAN paging message in the RAN notification area of the inactive IAB node. The RAN notification area of the IAB node may be configured by the host CU when the IAB node enters an inactive state. Once the IAB node recovers the RRC connection with the donor CU, the donor CU may send network management service data of the IAB node to the IAB node.

For example, the host CU stores a correspondence between the IAB MT and the IAB DU, or the host CU stores a correspondence between the IAB MT and an identifier of the IAB DU (for example, a correspondence between an inactive-radio network temporary identifier (I-RNTI) of the IAB MT and an identifier DU ID of the IAB DU), or the host CU stores a correspondence between the IAB MT and an identifier of a cell of the IAB DU (for example, a correspondence between an identifier I-RNTI of the IAB MT and an identifier NR CGI of the cell of the IAB DU). And the host CU determines the IAB MT of the IAB node according to the identification of the IAB DU or the cell identification of the IAB DU. The host CU sends a paging message to the IAB MT.

After receiving the paging message, the IAB MT performs step S1304 to perform an RRC recovery procedure with the host CU.

After step S1304, the host CU transmits DL data to the IAB DU.

After the IAB MT and the host CU perform the RRC recovery procedure, the user plane bearer corresponding to the DL data may be configured through the recovered RRC connection, for example: a Data Radio Bearer (DRB) or an RLC channel (RLC channel). The host CU sends DL data to the IAB MT through a corresponding user plane bearer, and the IAB MT sends the IAB DU through an internal interface.

Through steps S1301-S1304, the IAB node in the inactive state is woken up, and establishes an RRC connection with the host CU.

After the host node instructs the IAB node to enter the inactive state from the connected state, the host node to which the IAB node accesses may change due to mobility of the IAB node or cell selection when the IAB node needs to return to the connected state from the inactive state. The host node when the IAB node enters the non-activated state from the connected state is called an original host node, and the host node when the IAB node in the non-activated state initiates the RRC recovery flow is called a target host node. In the process of performing the RRC recovery procedure between the non-active IAB node and the target host node, an I-RNTI (long identity or short identity) may be sent to the target host node. The I-RNTI is allocated to the non-activated IAB node by the original host node, and the I-RNTI comprises the information of the original host node. And the target host node can determine the original host node according to the I-RNTI.

The target host node may obtain the context of the inactive IAB node from the original host node, including: the corresponding relationship between IAB MT and IAB DU is, for example: the corresponding relation between the I-RNTI of the IAB MT and the DU ID of the IAB DU, or the corresponding relation between the I-RNTI of the IAB MT and the NR CGI of the IAB DU cell. DU identifications and I-RNTIs are in one-to-one correspondence. Multiple NR CGIs may correspond to one I-RNTI. The correspondence may be sent in a list. For example, each row in the list includes one NR CGI and the I-RNTI to which the NR CGI corresponds.

The target host node may send a context request to the original host node, where the context request is used to request the original host node to send a correspondence between a distributed unit DU of the first IAB node and the mobile terminal MT of the first IAB node. According to the received context request, the original host node may send the corresponding relationship to the target host node.

The original host node may send downlink data of the inactive UE to the target host node. The original host node may send downlink data of the inactive UE to the target host node after receiving the context request sent by the target host node. Or, the original host node may receive a downlink data request sent by the target host node. The original host node may send the downlink data of the UE to the target host node according to the downlink data request.

Fig. 15 is a schematic flow chart of a communication method according to an embodiment of the present application.

The UE in the non-activated state enters the connected state by performing an RRC recovery flow, so that the network is accessed. Before the UE in the inactive state performs the RRC recovery procedure, a control check of the access cell needs to be performed to determine whether the attempt of currently accessing the cell is allowed, i.e., whether the UE is allowed to access the current cell.

The UE in the inactive state triggers an access attempt after determining that the access condition is satisfied. The inactive UE configures an access category (access category) and an access identity (access identity) according to the access condition.

The access condition may be triggered by the NAS layer of the UE, i.e. the access category and the access identity are determined by the NAS layer of the UE. Illustratively, the NAS layer of the UE discovers the access event (e.g., the NAS layer receives an upper layer transmission request), and the NAS layer maps the access event to an access category and one or more access identities. The access event comprises any one or more of the following events:

receiving a terminal originating (MO) voice call start instruction, an MO video call start instruction and the like from an upper layer;

receiving a short message request from an upper layer, wherein the short message request is used for requesting to send the MO short message through the NAS;

receiving a session establishment request from an upper layer, wherein the session establishment request is used for requesting to send an uplink NAS Transport (UL NAS Transport) message to establish a PDU session (session);

receiving a session modification request from an upper layer, the session modification request being for requesting sending an uplink NAS Transport (UL NAS Transport) message to modify a PDU session;

receiving a request for reestablishing user plane resources for an existing PDU session;

a PDU session that is informed that the user plane resources are pending has UL data to send, and so on.

The access condition may also be triggered by the RRC layer of the UE, i.e. the RRC layer of the UE determines the access category and the NAS layer of the UE determines the access identity. Illustratively, the RRC layer of the UE determines to perform an RNA update or receive a paging message, determines an access category corresponding to an access attempt (access attach) triggered by the RNA update or the paging message, and determines an access identifier corresponding to the access attempt by the NAS layer.

If the UE determines to perform RNA update, the RRC layer of the UE determines that the access category is 8, and the NAS layer of the UE determines one or more access identities.

If the UE receives the paging message, the RRC layer of the UE determines that the access category is 0, and determines one or more access identifications by the NAS layer of the UE.

The correspondence between the access category and the access attempt type is shown in table 1.

TABLE 1

Access class	Type of access attempt
0	Paging-induced MO signaling
1	UE configured as Multimedia Priority Service (MPS)
2	Incident event
3	NAS layer MO signaling for reasons other than paging
4	Multimedia Telephony (MMTEL) sound
5	Multimedia Telephony (MMTEL) video
6	Short Message Service (SMS)
7	MO data not belonging to other ranks
8	RRC layer MO signaling for reasons other than paging
9-31	Future standardized access class reservation
32-63	Operator-based categories

The access category takes a value of 0-63, illustratively, access category 0 indicates access control triggered for paging, access category 2 indicates access control triggered for emergency calls, access category 8 indicates access control triggered for RNA update, and so on. Access classes 9-31 are reserved for future standardized access classes and access classes 32-63 are reserved for operators.

The correspondence between the access identities and the configuration of the UE is shown in table 2.

TABLE 2

Access identification	UE configuration
0	UE for other configuration scenarios
1	UE configured as Multimedia Priority Service (MPS)
2	UE configured as Mission Critical Service (MCS)
3-10	Reservation
11	UE configured as Access Class (Access Class)11
12	UE configured as Access Class (Access Class)12
13	UE configured as Access Class (Access Class)13
14	UE configured as Access Class (Access Class)14
15	UE configured as Access Class (Access Class)15

The Access identifier is taken to be 0-15, and illustratively, the Access identifier 11-15 is taken to be consistent with an Access Class (Access Class) stored in a Universal Subscriber Identity Module (USIM) card of the UE, and is used for indicating that the Access Class is a special high-priority user of any one of 11-15. The access identities 3-10 are reserved for future use.

An Access Stratum (AS) of the UE, for example, an RRC layer of the UE, performs an access control check based on the access identifier and the access type determined by the UE. After the access control check is passed, the RRC recovery process is carried out,

similarly, the non-activated IAB node may also perform an access control check before performing RRC recovery.

There are several possibilities for access control checking of IAB nodes.

As a possible approach, a new event and a new access category are defined for the IAB MT.

When the IAB DU receives the access request sent by the child node, the IAB DU sends to an upper layer (upper layer) of the IAB MT, for example: and sending indication information to the NAS layer of the IAB MT, wherein the indication information is used for indicating the NAS layer of the IAB MT to discover an access event and determining an access category and an access identifier corresponding to the access event. The access request sent by the child node may be a preamble sequence, or may be an RRC recovery request or an RRC establishment request.

When the IAB DU is to transmit data (for example, OAM traffic), the IAB DU is transmitted to an upper layer of the IAB MT, for example: and sending the indication information to the NAS layer of the IAB MT so that the NAS layer of the IAB MT discovers the access event and determines the access category and the access identification corresponding to the access event.

Illustratively, the access event is a newly defined access event for the IAB node, and may be the receipt of an access request from a child node or the receipt of an UL transmission request.

The NAS layer of the IAB MT maps this event to one access category. The Category may be an Access Category that has been defined, such as Access Category 0. The access category may also be a reserved access category, such as: access Category 9. The standard defines that access attempts corresponding to certain specific access categories are allowed, and therefore, the RRC layer of the IAB MT determines whether an access attempt is allowed according to the access category. Illustratively, the standard defines that access attempts corresponding to access categories corresponding to IAB nodes are allowed. If the access attempt is allowed, the IAB MT makes a recovery of the RRC connection with the host CU.

Optionally, in addition to the access event that the IAB MT switches from inactive state to connected state, other events may be: an access event of the initial random access network of the IAB MT, an access event of RLF recovery by the IAB MT, etc. may be mapped to the defined access category.

Multiple events may also be defined, each of which may be mapped to the same or different access categories. For example, event 1 is defined as the NAS layer receiving the access indication, and event 1 is defined as the NAS layer receiving the transmission request. According to the mapping relation between the event and the category, the event 1 and the event 2 can be mapped on different access categories.

Alternatively, the NAS layer may map the events to the same or different access identities.

As another possibility, an access category is defined for the IAB MT.

When the IAB DU receives the access request sent by the child node, the IAB DU sends indication information to the RRC layer of the IAB MT, so that the RRC layer of the IAB MT determines the access category corresponding to the access attempt.

When the RRC layer of the IAB MT receives the paging message of the IAB node, the RRC layer of the IAB MT determines an access category corresponding to the access attempt triggered by the paging message.

The RRC layer of the IAB MT determines the access category. The Category may be an Access Category that has been defined, such as Access Category 0. The access category may also be a reserved access category, such as: for example: access Category 9.

The RRC layer of the IAB MT determines whether access is allowed according to the access category. Illustratively, the standard defines that access attempts corresponding to access categories corresponding to IAB nodes are allowed.

The RRC layer may determine that the access identity may be one of the access categories reserved in table 1.

It should be appreciated that the RRC layer may determine the same access category for two different cases, an access request, a paging message, of the child node, or the RRC layer may determine a different access category for each of the two cases.

As a third possibility, a new Access Class is defined for the IAB MT.

The Access Class of the IAB node may be configured for the USIM card of the IAB node. When the trigger condition is met, the RRC layer of the IAB MT determines an Access identifier corresponding to the Access attempt of the IAB MT according to the Access Class configured in the USIM card. When the IAB DU receives the access request sent by the child node, the IAB DU sends indication information to the RRC layer of the IAB MT, so that the RRC layer of the IAB MT determines an access identifier corresponding to the access attempt.

When the RRC layer of the IAB MT receives the paging message of the IAB node, the RRC layer of the IAB MT determines an access identifier corresponding to the access attempt triggered by the paging message.

When the IAB DU has data (for example, OAM service) to be transmitted, the IAB DU sends indication information to an RRC layer of the IAB MT so that the RRC layer of the IAB MT determines an access identifier corresponding to the access attempt.

In step S1401, the IAB-MT performs access control verification.

The IAB MT determines whether to allow the access to the current cell according to the determined access category. If the access is allowed, the verification is considered to be successful, and the process proceeds to step S1402. Otherwise, the IAB MT determines whether to allow access to the current cell according to the determined access identifier, and if the access is allowed, proceeds to step S1402.

Illustratively, the IAB MT checks, according to the determined access identifier, a Unified Access Control (UAC) Information Element (IE) (UAC-barringforessability IE) parameter carrying an access identifier carried in a System Information Block (SIB) 1 in a system broadcast message sent by the parent node. The uac-barringforaccessibility IE parameter represents the correspondence between the access identifier and whether to allow access in a bitmap (bitmap) manner, that is, each 1bit corresponds to an access identifier, and if the bit is set to 0, it indicates that the access attempt corresponding to the access identifier is allowed. The parent node may be other IAB nodes or a host node.

The judgment according to the access identification and the access category can be carried out simultaneously or according to the sequence. If either one of the access identifier and the access category is allowed to be accessed, step S1402 is performed.

If the access attempt of the IAB MT is allowed by the above-mentioned judgment according to the access identifier and the access category, step S1402 is performed; otherwise, the IAB MT may generate a random number between 0 and 1, and if the random number is smaller than the value of the uac-BarringFactor field in the SIB1, it indicates that the access attempt is allowed, and step S1402 is performed.

The IAB MT may start a timer if access attempts by the IAB MT through the random number are prohibited. For example, the IAB MT may generate a random number between 0 and 1 again, and start the timer T390 for the access attempt corresponding to the access category (the timing Time of the T390 is determined according to the random number generated by the IAB MT, and the parameter of the uac-Barring Time field in the SIB 1). Before the timer expires, the IAB MT can no longer initiate an access attempt.

In step S1402, an RRC setup procedure or an RRC recovery procedure is performed.

Through steps S1401-S1402, the access control verification of the inactive IAB MT during the access process is realized.

Fig. 16 is a schematic flowchart of a wireless communication method according to an embodiment of the present application, and illustrates an RRC recovery procedure.

In step S1501, the IAB-MT in the inactive state sends a preamble sequence to the host DU.

In step S1502, the host DU sends an RAR message to the IAB-MT, where the RAR message carries the C-RNTI allocated by the host DU in the access cell for the IAB-MT.

In step S1503, the IAB-MT sends an RRC recovery Request (RRC Resume Request) message to the host DU for requesting recovery of the RRC connection.

When the UE in the non-activated state performs RRC recovery, the sent RRC Resume Request message carries information with different reason indication information.

The triggering conditions for RRC recovery of the non-active IAB node are different from those for RRC recovery of the non-active UE. New cause indication information may be defined for the IAB node. The reason indication information sent by the IAB-MT to the host DU may be located in a new field or an existing field in the RRC Resume Request message.

Optionally, the RRC Resume Request message sent by the IAB-MT to the host DU may carry reason indication information. The reason indication information may be used to indicate a reason for performing the RRC recovery procedure. The reason may be an access request of the child node, a called request of the child node, or a wake-up request of the host node, and the like, that is, the reason indication information is used to indicate a trigger condition for triggering the RRC recovery procedure. The reason indication information may include one reason value corresponding to the trigger condition of all RRC recovery procedures, or may include a plurality of reason values, where different reason values correspond to different trigger conditions of RRC recovery procedures. The trigger condition may correspond to a cause value, and one cause value may correspond to a plurality of trigger conditions. The host node can acquire the reason for the IAB node to perform RRC connection recovery according to the reason indication information, so that different processing can be performed for RRC connection recovery procedures triggered by different reasons. For example, when the parent node is highly loaded, RRC recovery due to one or more reasons may be rejected, i.e., the parent node may reject RRC recovery due to one or more recovery conditions.

Optionally, the RRC Resume Request message may carry IAB node indication information, where the IAB node indication information is used to indicate that the RRC connection recovery is for the IAB node, or is used to indicate that the IAB node triggers an RRC recovery procedure. The host node may determine that the RRC recovery procedure is triggered by the IAB node, rather than by the normal UE, according to the IAB node indication information. With the IAB node indication information, the IAB node may indicate to the host node that the access procedure was initiated by the IAB node through a shorter field. The host node may configure a higher priority for this RRC recovery procedure.

In step S1504, the host DU forwards the RRC Resume Request message to the host CU. Illustratively, the host DU sends the RRC response Request Message to the host CU encapsulated in an Initial UL RRC Message Transfer (Initial UL RRC Message Transfer) Message. Illustratively, the Initial UL RRC Message Transfer Message also carries the NR CGI of the host DU accessed by the IAB-MT, and the identity C-RNTI of the IAB-MT in the cell.

In step S1505, the hosting CU sends an IAB-MT context setup request message to the hosting DU for requesting the hosting DU to set up a context of the IAB-MT.

The context of an IAB node includes the correspondence between IAB MT and IAB DU, for example: the corresponding relation between the I-RNTI of the IAB MT and the DU ID of the IAB DU, or the corresponding relation between the I-RNTI of the IAB MT and the NR CGI of the IAB DU cell.

In step S1506, after the host DU establishes the IAB-MT context, the host DU sends an IAB-MT context setup response message to the host CU, where the IAB-MT context setup response message is used for the host DU to confirm that the IAB-MT context setup is completed.

In step S1507, the host CU generates RRC recovery information and transmits the RRC recovery information to the host DU.

In step S1508, the host DU transmits the RRC recovery information to the IAB-MT.

In step S1509, the IAB-MT transmits RRC recovery complete information to the host DU.

In step S1510, the host DU will send RRC recovery complete information to the host CU.

The RRC recovery procedure described above is merely exemplary. More or fewer steps may be included when the IAB node performs RRC recovery with the host node.

Fig. 17 is a schematic structural diagram of an apparatus of an IAB node according to another embodiment of the present application. The apparatus 1700 includes a determination module 1710 and a trigger module 1720.

The determining module 1710 is configured to determine that any one or more of the following trigger conditions are satisfied:

the apparatus 1700 receives an access request sent by a child node, the child node comprising a second IAB node and/or a user equipment, UE,

apparatus 1700 receives a paging message triggered by a home node,

device 1700 has data to send;

the RRC layer or F1AP layer of the apparatus 1700 receives a connection recovery indication of an upper layer;

the triggering module 1720 is used to trigger restoration of a wireless connection with a host node.

Optionally, the apparatus 1700 further comprises:

an obtaining module, configured to obtain, according to a trigger condition that is satisfied, an access flag corresponding to the trigger condition;

the checking module is used for carrying out access control checking according to the access mark;

the triggering module 1720 is configured to trigger recovery of a radio connection with the host node when the access control check passes.

Optionally, the access label is an access label associated with the IAB node.

Optionally, the non-access stratum NAS of the apparatus 1700 is configured to obtain, according to the satisfied trigger condition, the access event corresponding to the satisfied trigger condition, where the access event is an access event associated with an IAB node;

the obtaining module is configured to obtain the access flag corresponding to the access event according to the access event.

Optionally, the apparatus 1700 further includes a transceiver module configured to send a radio connection recovery request message to the host node, where the RRC recovery request message includes cause indication information, and the cause indication information corresponds to the satisfied trigger condition.

Optionally, the apparatus 1700 further includes a transceiver module configured to send IAB node indication information to the host node, where the IAB node indication information is used to indicate that the radio connection restoration is a radio connection restoration of an IAB node.

Optionally, the satisfied trigger condition includes that the apparatus 1700 receives access requests sent by child nodes, where the number of the access requests is greater than or equal to a threshold, or the number of the child nodes is greater than or equal to a threshold.

Optionally, the apparatus 1700 further includes a transceiver module, configured to receive the threshold value sent by the host node.

Optionally, the apparatus 1700 is a relay device, and the host node is a base station.

Optionally, the paging message is sent by the host node under a condition that the host node receives downlink data of the inactive UE and/or the host node receives a first paging message of the idle UE.

Fig. 18 is a schematic structural diagram of an access network device according to an embodiment of the present application. The access network device 1800 includes a determination module 1810 and a transceiver module 1820.

The determining module 1810 is configured to determine that any one or more of the following trigger conditions are satisfied:

the access network equipment receives downlink data of the UE in the inactive state,

the access network equipment receives a first paging message of idle-state UE;

a transceiver module 1820, configured to send a second paging message to the first access backhaul integrated IAB node, where the second paging message is used to indicate the first IAB node and then trigger a wireless connection restoration between the first IAB node and a host node, and the host node is the access network device or the second host node.

Optionally, the met trigger condition includes that the access network device receives downlink data of the inactive UE, and the determining module 1810 is further configured to determine the first IAB node according to a radio access network RAN notification area of the inactive UE.

Optionally, the satisfied trigger condition includes that the access network equipment receives a first paging message of idle-state UE,

the determining module 1810 is further configured to determine the first IAB node according to a tracking area identity, TAI, list of the first paging message.

Optionally, the transceiver module 1820 is further configured to receive a radio connection recovery request message sent by the first IAB node;

the transceiver module 1820 is further configured to send a context request to a third donor node, where the context request is used to request the third donor node to send correspondence information between the distributed unit DU of the first IAB node and the mobile terminal MT of the first IAB node;

the transceiver module 1820 is further configured to receive the correspondence information sent by the third host node.

Optionally, the correspondence information includes:

the DU identification of the DU of the first IAB node and the inactive state radio network temporary identification I-RNTI of the MT of the first IAB node, and/or

A new radio cell global identity NR CGI of the first IAB node DU and an I-RNTI of the MT of the first IAB node.

Optionally, the radio connection resumption request message carries an identifier of a first IAB node, where the identifier of the first IAB node includes an identifier of the third host node.

Optionally, the first IAB node is a relay device or a device providing data backhaul, and the access network device is a base station.

Fig. 19 is a schematic structural diagram of an access backhaul integrated IAB device according to an embodiment of the present application. Apparatus 1900 includes a processor 1910, a communication interface 1920.

A processor 1910 configured to determine that any one or more of the following triggering conditions are met:

the apparatus 1900 receives an access request sent by a child node, the child node comprising a second IAB node and/or a user equipment, UE,

apparatus 1900 receives a paging message triggered by a host node,

device 1900 has data to send;

the RRC layer or F1AP layer of the device 190 receives the connection recovery indication of the upper layer;

communication interface 1920 is configured to trigger restoration of a wireless connection with a host node.

Optionally, the processor 1910 is configured to obtain, according to a trigger condition that is met, an access flag corresponding to the trigger condition;

a processor 1910 configured to perform access control verification according to the access flag;

processor 1910 is configured to trigger a radio connection restoration with a host node by the IAB apparatus when the access control check passes.

Optionally, the access label is an access label associated with the IAB node.

Optionally, the non-access stratum NAS of the IAB apparatus is configured to, according to a satisfied trigger condition, obtain the access event corresponding to the satisfied trigger condition, where the access event is an access event associated with an IAB node;

processor 1910 is configured to, according to the access event, obtain the access flag corresponding to the access event.

Optionally, the communication interface 1920 is further configured to send a wireless connection restoration request message to the host node, where the wireless connection restoration request message includes cause indication information, and the cause indication information corresponds to the satisfied trigger condition.

Optionally, the communication interface 1920 is further configured to send IAB node indication information to the host node, where the IAB node indication information is used to indicate that the radio connection restoration is a radio connection restoration of an IAB node, and the IAB node indication information is carried in a radio connection restoration request message or a radio connection restoration completion message.

Optionally, the satisfied trigger condition includes that the IAB apparatus receives access requests sent by child nodes, where the number of the access requests is greater than or equal to a threshold value, or the number of the child nodes is greater than or equal to a threshold value.

Optionally, the communication interface 1920 is further configured to receive the threshold value sent by the host node.

Optionally, the IAB apparatus is a relay device or a device providing data backhaul, and the host node is a base station.

Fig. 20 is a schematic structural diagram of an access network device according to an embodiment of the present application. Access network apparatus 2000 includes a processor 2010 and a communication interface 2020.

A processor 2010 for determining that any one or more of the following triggering conditions are met:

the access network device 2000 receives downlink data of the inactive UE,

the access network device 2000 receives a first paging message of the idle-state UE;

a communication interface 2020, configured to send a second paging message to the first access backhaul integrated IAB node, where the second paging message is used to indicate that the first IAB node triggers recovery of a wireless connection with a host node, and the host node is the access network device 2000 or a second host node.

Optionally, the satisfied trigger condition includes that the access network device 2000 receives downlink data of an inactive UE, and the processor 2010 is further configured to determine the first IAB node according to a radio access network RAN notification area of the inactive UE.

Optionally, the satisfied trigger condition includes that the access network device 2000 receives a first paging message of an idle UE, and the processor 2010 is further configured to determine the first IAB node according to a tracking area identity, TAI, list of the first paging message.

Optionally, communication interface 2020 is further configured to receive a radio connection resumption request message sent by the first IAB node;

communication interface 2020 is further configured to send a context request to a third donor node, where the context request is used to request that the third donor node send correspondence information between the distributed unit DU of the first IAB node and the mobile terminal MT of the first IAB node;

the communication interface 2020 is further configured to receive the correspondence information sent by the third host node.

Optionally, the correspondence information includes:

the DU identification of the DU of the first IAB node and the inactive state radio network temporary identification I-RNTI of the MT of the first IAB node, and/or

A new radio cell global identity NR CGI of the first IAB node DU and an I-RNTI of the MT of the first IAB node.

Optionally, the radio connection resumption request message carries an identifier of a first IAB node, where the identifier of the first IAB node includes an identifier of the third host node.

Optionally, the first IAB node is a relay device or a device providing data backhaul, and the access network device 2000 is a base station.

An embodiment of the present application further provides a communication system, which includes the first IAB node and the host node described above.

An embodiment of the present application further provides a computer program storage medium, which is characterized in that the computer program storage medium has program instructions, and when the program instructions are executed by a processor, the processor is caused to execute the method for wireless communication in the foregoing.

An embodiment of the present application further provides a chip system, where the chip system includes at least one processor, and when the program instructions are executed in the at least one processor, the at least one processor is caused to execute the method of wireless communication in the foregoing.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The names of all nodes and messages in the present application are only names set for convenience of description, and the names may be different in an actual network, and it should not be understood that the present application defines the names of various nodes and messages. Rather, any name having the same or similar function as a node or message used in the present application is considered a method or equivalent substitution of the present application and is within the scope of the present application.

In the embodiments of the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, and means that there may be three relationships, for example, a and/or B, and may mean that a exists alone, a and B exist simultaneously, and B exists alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple. It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (29)

1. A method of wireless communication, comprising:

   the first access backhaul integrated IAB node determines that any one or more of the following trigger conditions are met:

   the first IAB node receives an access request sent by a child node, wherein the child node comprises a second IAB node and/or User Equipment (UE),

   the first IAB node receives a paging message triggered by the home node,

   the first IAB node has data to send,

   the RRC layer or F1application protocol F1AP layer of the first IAB node receives the connection recovery indication of the upper layer;

   the first IAB node triggers a wireless connection restoration with the host node.
2. The method of claim 1, wherein before the first IAB node triggers restoration of the wireless connection with the host node, the method further comprises:

   the first IAB node obtains an access mark corresponding to the trigger condition according to the trigger condition;

   the first IAB node carries out access control verification according to the access mark;

   the first IAB node triggering a radio resource control radio connection recovery with a host node, comprising:

   and when the access control check is passed, the first IAB node triggers the recovery of the wireless connection with the host node.
3. The method of claim 2, wherein the access label is an access label associated with an IAB node.
4. The method of claim 2 or 3, wherein the obtaining, by the first IAB node, the access flag corresponding to the trigger condition according to the trigger condition being met comprises:

   according to the satisfied trigger condition, the non-access stratum (NAS) of the first IAB node obtains the access event corresponding to the satisfied trigger condition, wherein the access event is an access event associated with the IAB node;

   and the first IAB node obtains the access mark corresponding to the access event according to the access event.
5. The method according to any one of claims 1-4, further comprising:

   the first IAB node sends a radio connection restoration request message to the host node, the radio connection restoration request message including cause indication information, the cause indication information corresponding to a trigger condition being met.
6. The method according to any one of claims 1-5, further comprising:

   the first IAB node sends IAB node indication information to the host node, wherein the IAB node indication information is used for indicating that the wireless connection recovery is the wireless connection recovery of the IAB node.
7. The method of any of claims 1-6, wherein the trigger condition met comprises the first IAB node receiving access requests sent by child nodes, wherein the number of access requests is greater than or equal to a threshold value, or wherein the number of child nodes is greater than or equal to a threshold value.
8. The method of claim 7, wherein before the first IAB node determines that a trigger condition is met, the method further comprises:

   and the first IAB node receives the threshold value sent by the host node.
9. The method according to any of claims 1-8, wherein the first IAB node is a relay device or a device providing data backhaul, and the host node is a base station.
10. A method of wireless communication, comprising:

    the first host node determines that any one or more of the following trigger conditions are met:

    the first host node receives downlink data of the UE in the inactive state,

    the first host node receives a first paging message of idle UE;

    the first host node sends a second paging message to the first access backhaul integrated IAB, wherein the second paging message is used for indicating the first IAB to trigger the recovery of the wireless connection between the first IAB and the host node, and the host node is the first host node or the second host node.
11. The method of claim 10, wherein the trigger condition being met comprises the first host node receiving downlink data of an inactive UE,

    before the first host node sends the second paging message to the first IAB node, the method further includes: and the first host node determines the first IAB node according to a Radio Access Network (RAN) notification area of the UE in an inactive state.
12. The method of claim 10, wherein the trigger condition being met comprises the first host node receiving a first paging message for an idle UE,

    before the first host node sends the second paging message to the first IAB node, the method further includes:

    and the first host node determines the first IAB node according to a Tracking Area Identification (TAI) list of the first paging message.
13. The method of any of claims 10-12, wherein the first IAB node is a relay device or a device providing data backhaul, and wherein the first host node is a base station.
14. An access backhaul integrated IAB apparatus, comprising:

    a determination module configured to determine that any one or more of the following trigger conditions are satisfied:

    the IAB device receives an access request sent by a child node, wherein the child node comprises a second IAB node and/or User Equipment (UE),

    the IAB device receives a paging message triggered by a home node,

    the IAB device has data to send,

    the Radio Resource Control (RRC) layer or the F1application protocol (F1 AP) layer of the IAB node receives a connection recovery indication of an upper layer;

    and the triggering module is used for triggering the wireless connection between the host node and the host node to recover.
15. The apparatus of claim 14, comprising:

    an obtaining module, configured to obtain, according to a trigger condition that is satisfied, an access flag corresponding to the trigger condition;

    the checking module is used for carrying out access control checking according to the access mark;

    the triggering module is configured to trigger the IAB device to recover the wireless connection with the host node when the access control check passes.
16. The apparatus of claim 15, wherein the access label is an access label associated with an IAB node.
17. The apparatus according to claim 15 or 16, wherein the non-access stratum NAS of the IAB apparatus is configured to, according to the satisfied trigger condition, obtain the access event corresponding to the satisfied trigger condition, where the access event is an access event associated with an IAB node;

    the obtaining module is configured to obtain the access flag corresponding to the access event according to the access event.
18. The apparatus according to any one of claims 14-17, comprising:

    a transceiver module, configured to send a wireless connection recovery request message to the host node, where the wireless connection recovery request message includes reason indication information, and the reason indication information corresponds to a satisfied trigger condition.
19. The apparatus according to any one of claims 14-18, comprising:

    a transceiver module, configured to send IAB node indication information to the host node, where the IAB node indication information is used to indicate that the radio connection recovery is the radio connection recovery of an IAB node.
20. The apparatus of any of claims 14-19, wherein the trigger condition met comprises the IAB apparatus receiving access requests sent by child nodes, the number of access requests being greater than or equal to a threshold value, or the number of child nodes being greater than or equal to a threshold value.
21. The apparatus of claim 20, comprising:

    and the transceiver module is used for receiving the threshold value sent by the host node.
22. The apparatus according to any of claims 14-21, wherein the IAB apparatus is a relay device or a device providing data backhaul, and the host node is a base station.
23. An access network device, comprising:

    a determination module configured to determine that any one or more of the following trigger conditions are satisfied:

    the access network equipment receives downlink data of the UE in the inactive state,

    the access network equipment receives a first paging message of idle-state UE;

    a transceiver module, configured to send a second paging message to the first access backhaul integrated IAB node, where the second paging message is used to indicate that the first IAB node triggers recovery of a wireless connection with a host node, and the host node is the access network device or a second host node.
24. The access network device of claim 23, wherein the satisfied trigger condition comprises that the access network device receives downlink data of inactive UE,

    the determining module of the access network device is further configured to determine the first IAB node according to a radio access network RAN notification area of the inactive UE.
25. The access network device of claim 23, wherein the trigger condition being met comprises the access network device receiving a first paging message for an idle UE,

    the determining module of the access network device is further configured to determine the first IAB node according to a tracking area identity, TAI, list of the first paging message.
26. The access network device of any of claims 23-25, wherein the first IAB node is a relay device or a device providing data backhaul, and the access network device is a base station.
27. A wireless communication device, comprising: at least one processor and a communication interface for the communication device to interact with other communication devices, the program instructions, when executed in the at least one processor, causing the communication device to perform the method of any of claims 1 to 13.
28. A computer program storage medium having program instructions which, when executed by a processor, cause the processor to perform the method of wireless communication of any one of claims 1-13.
29. A chip system, comprising at least one processor, wherein program instructions, when executed in the at least one processor, cause the at least one processor to perform the method of wireless communication of any of claims 1-13.

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