CN110740485A - Node selection method and device for integrated access and backhaul system - Google Patents

Abstract

The present invention relates to a node selection method for an integrated access and backhaul system deployed in a new wireless NR, using a massive multiple-input multiple-output MIMO system, comprising a plurality of IAB nodes, some of which For the donor IAB node; LTE RRC signaling needs to be enhanced to support the control signaling required for the IAB node integration process to dynamically switch the backhaul link; the IAB node supports the access chain in TDM, FDM and SDM with half-duplex constraints multiplexing the backhaul link and the backhaul link; the selection method includes: when the IAB node performs cell selection/reselection, the IAB node with fewer hops backhauled to the IAB donor should have a higher priority, and The load on the IAB node should be low. This allows for flexible, very dense deployment of NR cells, and connecting to IAB nodes with fewer backhaul hops can reduce latency and achieve better resource efficiency.

Description

Node selection method and device for integrated access and backhaul system

technical field

The present invention relates to wireless communication technology, and more particularly, to link assistance information reporting and data transmission in wireless communication systems.

Background technique

A wireless communication system may include a base station (hereinafter referred to as "BS") that communicates with user equipment (hereinafter referred to as "UE"). UEs may include mobile devices (eg, cell phones, tablets, laptops, Internet of Things (IoT) devices, etc.). The quality of the communication link or channel between the BS and the UE may be degraded due to various factors, such as blockage of buildings, relatively long distance between the BS and the UE, and so on. A solution to this problem may include deploying a relay node (hereinafter referred to as "RN") in a wireless communication system to enhance and/or extend the coverage of the BS.

A BS that communicates with a UE through one or more RNs is called a donor BS. These RNs form a backhaul link with the donor BS, allowing the UE to reach the donor BS through one or more RNs. The signal from the UE can also simply be sent directly from one RN to the donor BS. An Integrated Access and Backhaul (IAB) system, evolved from the RN deployment in 3GPP, is being developed to support multi-hop relaying in New Radio (NR) communication networks.

However, the backhaul link can fail in some cases, so a new solution is needed to protect data or signal transmission.

SUMMARY OF THE INVENTION

The present invention has been made to address at least the problems and disadvantages described above and to provide at least the benefits described below. Accordingly, one aspect of the present invention provides a node selection method for an integrated access and backhaul system deployed in new wireless NR using massive multiple-input multiple-output MIMO systems, including multiple IAB nodes, some of which are donor IAB nodes; LTE RRC signaling needs to be enhanced to support the control signaling required for the IAB node integration process to dynamically switch the backhaul link; IAB nodes support TDM, FDM with half-duplex constraints With the SDM, the access link and the backhaul link are multiplexed; it is characterized in that, including:

When an IAB node performs cell selection/reselection, the IAB node with fewer hops back to the IAB donor should have higher priority, and the load of the IAB node should be lower.

Further, it also includes donor IAB reselection, wherein,

Step 0: The IAB node is configured by the serving IAB donor 1 to report information, the measurement result of the candidate backhaul link between the IAB node and the adjacent IAB donor,

Step 1: The IAB node reports the auxiliary information to the service donor IAB,

Step 2: Once the source donor IAB decides to handover based on the measurement results, the source donor IAB sends a backhaul handover request to the target donor IAB,

Step 3: If the resources in the target IAB donor are available, the target IAB donor will reply ACK to the source IAB donor,

Step 4: The source IAB donor sends the backhaul handover command to the IAB node,

Step 5: Once the backhaul handover command message is received, the IAB node will connect to the target IAB donor,

Step 6: After the IAB node is successfully connected, the target IAB donor transmits the complete backhaul switch to the source IAB donor.

Further, it also includes next-hop IAB node reselection, wherein,

Both IAB Node 1 and IAB Node 2 are within the coverage of the IAB Donor, however, IAB Node 3 is beyond the coverage of the Donor IAB, therefore, IAB Node 3 is connected to the IAB Donor relayed by IAB Node 1 or IAB Node 2,

Step 0: The IAB donor in the service configures the IAB node to report information, measurement results, delay or load information,

Step 1: The IAB node reports auxiliary information, the measurement results of the backhaul links related to IAB node2 and IAB node3,

Step 2: Once the IAB donor decides to perform an IAB node handover, the IAB donor sends a backhaul handover request to the target IAB node 2,

Step 3: The target IAB node 2 replies ACK to the IAB donor,

Step 4: The IAB donor sends a backhaul handover command to the IAB node 3 relayed by the IAB node 1, FFS: the content of the backhaul handover command is transparent to the IAB node1,

Step 5: After the IAB node 3 receives the backhaul handover command message, it connects to the target IAB node 2,

Step 6: After the IAB node 3 is successfully connected, the target IAB node 2 will send the complete backhaul exchange to the donor IAB,

Step 7: The IAB donor transmits the backhaul release to the IAB node 1,

In step 1, the IAB node will report some information to help the donor IAB in the service to make a decision, the following information will help the donor IAB,

- a measurement of the link between IAB Node 3 and the candidate IAB Node, or

- delay information for candidate IAB nodes, or

- Loading information of candidate IAB nodes;

In the case of IAB node reselection, the IAB node shall report auxiliary information including measurement results, latency information and load information to the donor IAB.

Further, the slot boundaries of the IAB node and the donor IAB node should be aligned with integer multi-symbol shifts.

Further, described IAB node topology management has two types: centralized topology management and distributed topology management; in centralized topology management, the topology of the entire IAB network is managed by a centralized entity, which maintains the global topology of the IAB network ; Centralized entity is located on the donor IAB, core network or application server; In distributed topology management, each IAB node and IAB donor has its own topology management entity and maintains local topology.

In another aspect, the present invention proposes a node selection device for an integrated access and backhaul system, the integrated access and backhaul IAB system deployed in the new wireless NR, using a massive multiple-input multiple-output MIMO system, including multiple IABs nodes, some of which are donor IAB nodes; LTE RRC signaling needs to be enhanced to support control signaling required for the IAB node integration process to dynamically switch backhaul links; IAB nodes support TDM, FDM and SDM with half-duplex constraints The access link and the backhaul link are multiplexed in the middle; it is characterized in that, including:

The selection means is used for when the IAB node performs cell selection/reselection, the IAB node with less hops back to the IAB donor should have higher priority, and the load of the IAB node should be lower.

Further, a donor IAB reselection device is also included to perform the following steps, wherein,

Step 0: The IAB node is configured by the serving IAB donor 1 to report information, the measurement result of the candidate backhaul link between the IAB node and the adjacent IAB donor,

Step 1: The IAB node reports the auxiliary information to the service donor IAB,

Step 2: Once the source donor IAB decides to handover based on the measurement results, the source donor IAB sends a backhaul handover request to the target donor IAB,

Step 3: If the resources in the target IAB donor are available, the target IAB donor will reply ACK to the source IAB donor,

Step 4: The source IAB donor sends the backhaul handover command to the IAB node,

Step 5: Once the backhaul handover command message is received, the IAB node will connect to the target IAB donor,

Step 6: After the IAB node is successfully connected, the target IAB donor transmits the complete backhaul switch to the source IAB donor.

Further, a next-hop IAB node reselection device is also included to perform the following steps, wherein,

Both IAB Node 1 and IAB Node 2 are within the coverage of the IAB Donor, however, IAB Node 3 is beyond the coverage of the Donor IAB, therefore, IAB Node 3 is connected to the IAB Donor relayed by IAB Node 1 or IAB Node 2,

Step 0: The IAB donor in the service configures the IAB node to report information, measurement results, delay or load information,

Step 1: The IAB node reports auxiliary information, the measurement results of the backhaul links related to IAB node2 and IAB node3,

Step 2: Once the IAB donor decides to perform an IAB node handover, the IAB donor sends a backhaul handover request to the target IAB node 2,

Step 3: The target IAB node 2 replies ACK to the IAB donor,

Step 4: The IAB donor sends a backhaul handover command to the IAB node 3 relayed by the IAB node 1, FFS: the content of the backhaul handover command is transparent to the IAB node1,

Step 5: After the IAB node 3 receives the backhaul handover command message, it connects to the target IAB node 2,

Step 6: After the IAB node 3 is successfully connected, the target IAB node 2 will send the complete backhaul exchange to the donor IAB,

Step 7: The IAB donor transmits the backhaul release to the IAB node 1,

In step 1, the IAB node will report some information to help the donor IAB in the service to make a decision, the following information will help the donor IAB,

- a measurement of the link between IAB Node 3 and the candidate IAB Node, or

- delay information for candidate IAB nodes, or

- Loading information of candidate IAB nodes;

In the case of IAB node reselection, the IAB node shall report auxiliary information including measurement results, latency information and load information to the donor IAB.

Further, the slot boundaries of the IAB node and the donor IAB node should be aligned with integer multi-symbol shifts.

Further, described IAB node topology management has two types: centralized topology management and distributed topology management; in centralized topology management, the topology of the entire IAB network is managed by a centralized entity, which maintains the global topology of the IAB network ; Centralized entity is located on the donor IAB, core network or application server; In distributed topology management, each IAB node and IAB donor has its own topology management entity and maintains local topology.

The present invention achieves the following beneficial effects:

One of the potential technologies that the present invention aims at enabling future cellular network deployment scenarios and applications is support for wireless backhaul and relay links, allowing for flexible and very dense deployment of NR cells without scaling down the density of the transmission network. Connecting to the IAB node with fewer backhaul hops can reduce delay and achieve better resource efficiency, which is also the effect that the present invention needs to achieve.

Description of drawings

The present invention is now described below with respect to various aspects of its preferred embodiments with reference to the accompanying drawings, in which:

Figure 1 shows the network system architecture of integrated access and backhaul links;

Fig. 2 shows the semi-static time slot format configuration schematic diagram of donor gNB and IAB node;

FIG. 3 shows a schematic diagram of the dynamic slot format configuration on the group common PDCCH through SFI;

Figure 4 shows a schematic diagram of multi-hop backhaul of an IAB node.

Detailed ways

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, embodiments of the present invention may take different forms and should not be construed as limited to the descriptions set forth herein. Accordingly, the embodiments are described below, by referring to the figures, only for the purpose of illustrating aspects of the present invention.

In the prior art, due to the larger available bandwidth of NR compared to LTE (eg mmWave spectrum) and the local deployment of massive MIMO or multi-beam systems in NR, the creation and deployment of integrated access and backhaul links has created a opportunity. This may allow for easier deployment of dense networks of self-backhauled NR cells in a more integrated manner, based on the many control and data channels/procedures defined to provide access to the UE. An example illustration of a network with such integrated access and backhaul links is shown in Figure 1, where relay nodes (rTRPs) can multiplex the access and backhaul links in time, frequency or space use.

For current network systems that integrate access and backhaul links, there are many factors to consider at the physical layer. The operation of the different links may be on the same or different frequencies (also referred to as "in-band" and "out-of-band" relays). While effective support of out-of-band relays is important for some NR deployment scenarios, it is critical to understand the requirements for in-band operation, which means that interworking with access links operating on the same frequency is more efficient Tight, to accommodate duplex constraints and avoid/mitigate operations is critical. interference.

Additionally, NR systems operating in mmWave spectrum present some unique challenges, including encountering severe short-term congestion, which current RRC-based handover mechanisms may not be able to easily due to the longer than short time required to complete the process. alleviate these problems. Deadline blocked. Overcoming short-term congestion in mmWave systems may require a fast RAN-based mechanism for handover between rTRPs, where core network involvement is not necessarily required. The need to alleviate short-term congestion for NR operation in mmWave spectrum, and the desire for easier deployment of self-backhauled NR cells, has created a need to develop an integrated framework that allows fast handover of access and backhaul links. need. Over-the-air (OTA) coordination between rTRPs can also be considered to mitigate interference and support end-to-end routing and optimization.

SA1 has established service requirements for wireless self-backhaul. Includes the following:

5G networks should enable operators to support wireless self-backhaul using NR and E-UTRA.

5G networks should support flexible and efficient wireless self-backhaul for indoor and outdoor scenarios.

5G networks should support flexible allocation of radio resources between access and backhaul functions.

5G networks should support autonomous configuration of access and wireless self-backhaul functions.

5G networks should support multi-hop wireless self-backhaul.

5G networks should support autonomous adaptation to the wireless self-backhaul network topology to minimize service interruptions.

5G networks should support topologically redundant connections over wireless self-backhaul.

For NSA deployments, SSB transport and system information are not transmitted. The initial access procedure will be through LTEPCell for NSA. To support IAB in NSA deployments, the IAB node can simply follow the LTE initial access procedure and play the role of a UE supporting LTE-NR dual connectivity. After initial LTE access, the IAB node needs to identify itself as an NR IAB node and request LTE-NR dual connectivity. LTE RRC signaling needs to be enhanced to support control signaling required for IAB node integration procedures such as route update and IAB DU setup with F1-AP setup procedure. These control signaling are part of the NR F1 control signaling during initial setup and IAB node control signaling. Once the IAB integration process is completed, the donor gNB will configure the LTE-NR bidirectional connection to the IAB node as an NR cell and as an SCG for the IAB node's backhaul link.

The IAB node will perform LTE initial access for NSA operations. LTE RRC signaling needs to be enhanced to support control signaling required for IAB node integration procedures, such as route update and IAB DU setup negotiation with F1-AP setup process, both SSB and CSI-RS can be used for IAB detection in phase 2 And measure candidate backhaul links to dynamically switch backhaul links. The radio resources used for backhaul link measurements will be configured relative to the candidate donor gNB. Under half-duplex constraints, the radio resources used by the IAB node to measure the backhaul link shall be UE-specific RS configuration to avoid potential cell-specific radio resource collisions that can be between the donor gNB and the IAB In the transmission to the UE, the synchronization node is based on different situations of the transmission timing. The radio resources used by the IAB node for candidate backhaul link measurements shall be configured and coordinated among the candidate donor gNBs to allow simultaneous measurements of multiple backhaul links, including serving and target donor gNBs. Using SSB in TDM/FDM with/without muting will limit the number of candidate backhaul links to measure. Since the IAB node will be considered as a UE in CONNECTED state, the CSI-RS resource for CSI or RRM measurement should be a good reference signal for backhaul link measurement. The configuration of CSI-RS resources for IAB backhaul link measurements is similar to UE CSI measurements from multiple beams for beam management or CoMP. Multiple NZP and ZP CSI-RS resources can be configured as references for backhaul link measurement and non-measured backhaul link interference mitigation for any candidate backhaul link, respectively, to allow an IAB node to measure multiple candidate backhaul links simultaneously.

Further, it may be considered to configure multiple NZP and ZP CSI-RS resources as a reference for the backhaul link measurement of any candidate backhaul link and the interference mitigation of non-measured backhaul links to allow the IAB node to measure multiple candidate backhaul links simultaneously road.

By serving the gNB, the CSI-RS resources configured for candidate backhaul link measurement can also be used for RRM measurement in the case where NZP and ZP CSI-RS resource configuration is coordinated between candidate backhaul links. The CSI-RS resources used for beam management or CSI measurement of the donor gNB should be reused for RRM measurement of IAB backhaul link as well as RLM measurement. The advantage of using CSI-RS for RRM and RLM measurement is that measurement performance can be improved when ZP CSI-RS is configured on the same REs of CSI-RS resources of neighboring cells to mitigate interference. .

The CSI-RS resources configured for beam management or CSI measurement of the donor gNB should be reused for RRM measurement as well as RLM measurement of the IAB backhaul link.

The use of CSI-RS as RS is of interest for RRM and RLM measurements of IAB backhaul links for Phase 2 discovery in unsynchronized network deployments. For the second phase discovery, the IAB node becomes active in serving the UE. In order to perform TDM operation in half-duplex constrained combat, the transmission time needs to be fixed under the assumption of full offset synchronization with the donor gNB and other IAB nodes. The transmission timing cases 1-7 studied in the IAB study do not work at all if the network is not fully synchronized (including offset synchronization). Therefore, the CSI-RS as the RS for the IAB node backhaul link measurement will work with different cases of DL/UL transmission timings that require offset synchronization between the IAB node and the donor gNB.

The CSI-RS used as the RS for the IAB node backhaul link measurement will work with different cases of DL/UL transmission timing requiring offset synchronization between the IAB node and the donor gNB.

In RAN1 #93, the IAB node supports multiplexing of access and backhaul links in TDM, FDM and SDM with half-duplex constraints. For in-band operation of backhaul links and IAB Uu access links, when one link is in transmit state and the other is in receive state, transmission side lobes will cause self-interference. The half-duplex constraint is to avoid self-interference in in-band operation. The antennas for the Uu link and the backhaul link need to be separated and isolated to contain interference from side lobes. Without antenna isolation, the backhaul link and Uu link transmit and receive need to be coordinated in time to minimize self-interference caused by side lobes. An IAB node will have symbols in transmission or reception on both the access link and the backhaul link.

Since NR systems are flexible in terms of system configuration (eg digital, DL/UL configuration and HARQ timing), a better interference mitigation solution is to have a coordinated DL/UL configuration between the access link and the backhaul link. The interference mitigation scheme for the IAB node is to coordinate DL/UL transmission with the donor gNB to avoid IAB DL transmission in the access link colliding with DL reception in the backhaul link, or to avoid UL supplementation on the access link being affected by UL transmission interference to the backhaul link on the IAB node. If the DL/UL slot format of the donor gNB is semi-statically configured by RRC, as shown in Figure 1, the IAB node can receive the DL/UL slot format configuration during the initial setup of the IAB node. The interference mitigation scheme is for the IAB node to configure the DL/UL slot format through the offset of the slot boundary to avoid simultaneous reception in one link and transmission in the other link, as shown in Figure 2.

If the DL/UL slot format is dynamically configured on the donor gNB and SFI is indicated on the group common PDCCH, the IAB can play the role of the UE and decode the group common PDCCH and determine its DL/UL slot format, as shown in Figure 3 As shown, the slot boundary on the IAB node starts with a delay of some symbols after DL transmission from the backhaul link, where the access link slot format dynamically adjusts each slot based on the SFI received from the donor gNB. From Figures 2 and 3, the interference mitigation of the IAB can be achieved by semi-statically or dynamically allocating the DL/UL slot configuration on the IAB node on the basis of the DL/UL slot configuration of the donor gNB.

As can be seen from Figures 2 and 3, the slot boundary of the IAB node should be offset by a few symbols relative to the slot boundary of the donor gNB to avoid between the access link and the backhaul link when one link transmits of self-interference while the other link is receiving. For UL transmission on the backhaul link, the transmission time will be determined by the TA command from the donor gNB, the TA being derived from the propagation delay. For the IAB backhaul link, since the IAB nodes are fixed, the propagation delay should be stable. Therefore, the minimum time interval for the advanced UL transmission time in the backhaul link can be specified and included in the calculation of the number of symbols of the GP in the slot. Therefore, the slot boundaries of the IAB node and the donor gNB should be aligned with integer multi-symbol shifts. Since each IAB node semi-statically aligns the slots with the symbol shifts from its donor gNB, it would be beneficial to configure the same number of OFDM symbol shifts. This will minimize co-channel interference for UEs covered by neighboring IAB nodes.

Therefore, the slot boundaries of the IAB node and the donor gNB should be aligned with integer multi-symbol shifts. The number of OFDM symbols offset at the slot boundaries of the IAB nodes should be configured to be the same for all IAB nodes in the cluster.

Furthermore, based on the current NR specification, the UE will perform measurements and select an appropriate cell based on RRC_IDLE state measurements and cell selection criteria, which are not optimal due to issues in the physical layer design. When camping on a cell, the UE should periodically search for a better cell according to the cell reselection criteria. If a better cell is found, it is selected. Likewise, if the IAB node MT part tries to connect to the parent IAB node, the cell selection and reselection scheme should be the same. But considering that different IAB nodes have different number of backhaul hops to reach the IAB donor, if the IAB node connects to the IAB donor with fewer hops to the IAB node, it will require less radio resources and less end-to-end delay .

As shown in Figure 4, IAB2 needs two hops to reach the donor IAB, while IAB-x only needs one hop to reach the donor IAB. Assuming that both IAB2 and IAB-x are suitable cells for IAB3, and IAB3 chooses to connect to IAB2, the packet transmission delay from the UE served by IAB3 to the IAB donor consists of four parts: 1) Delay between UE and IAB 3; 2) Delay between IAB3 and IAB2; 3) Delay between IAB2 and IAB1; 4) Delay between IAB1 and donor IAB. On the other hand, if IAB3 is connected to IABx, the packet transmission delay from the UE served by IAB3 to the IAB donor consists of only three parts. Therefore, connecting to an IAB node with fewer backhaul hops reduces latency and achieves better resource efficiency.

How to connect to an IAB node with fewer backhaul hops can reduce latency and achieve better resource efficiency. is an issue that must be considered.

Based on the above analysis, when the IAB node performs cell selection/reselection, the IAB node with fewer hops back to the IAB donor should have a higher priority. In addition to the hop count, in order to achieve load balancing, when the IAB node performs cell selection/reselection, the links with lower load should also be considered.

Therefore, when the IAB node performs cell selection/reselection, the IAB node with less backhaul hops should have higher priority, and the load of the IAB node should be lower.

In general, an IAB node does not have to establish a connection with every detected neighbor node. Instead, the IAB node only needs to select one or several neighboring cells for connection. This process can be thought of as topology management. There are two types of topology management: centralized topology management and distributed topology management. In centralized topology management, the topology of the entire IAB network is managed by a centralized entity that maintains the global topology of the IAB network. The centralized entity can be located on the donor IAB, core network or application server. In distributed topology management, each IAB node and IAB donor has its own topology management entity and maintains the local topology based on the exchange of information with neighboring nodes. In this section, the possible solutions chosen by the parent IAB will be analyzed based on centralized and distributed topology management, respectively.

To achieve the parent IAB node selection can be based on the control of a centralized topology management entity or a distributed topology management entity. The following operations should also be implemented.

When an IAB node is powered up, it can only select the appropriate serving IAB node by itself, since it cannot receive guidance from a centralized topology management entity until it is connected to the network. In this case, the IAB node can select and connect to a suitable IAB node like a normal UE. After connecting to the parent IAB node, the IAB node can obtain initial configuration parameters and perform measurements of neighboring cells. In addition, taking into account the changing channel environment and radio link, the IAB node has to update the measurement report to the centralized topology management entity. This means that each IAB will continue to perform measurements on neighboring cells and report to the centralized entity. After the centralized entity obtains topology information and measurement reports from an IAB node, it can determine which IAB node is the best parent IAB node for this IAB and keep that IAB node informed of its decisions. If the best parent IAB node is not the currently serving IAB node, the IAB may be detached from the currently serving IAB node and connected or handed over to the IAB node indicated by the centralized topology management entity.

Further, for centralized topology management, the IAB node has to perform measurements and send measurement reports to the centralized topology management entity.

Regarding the location of the centralized topology management entity, it is considered that the donor CU or donor node is eligible for centralized topology management. For the case of CU-DU splitting, the donor CU can obtain the measurement reports of all access UEs and the MT part of the IAB node, the connection between the IAB nodes and the congestion status of the backhaul link. Thus, the donor CU may be a centralized topology management entity. In the case of non-CU-DU splitting, the IAB donor node can obtain topology-related information from the IAB node through the Xn interface, and then make topology control decisions. However, this means that the Xn interface should be enhanced for topology-dependent information exchange.

It should also be noted that donor CUs or donor nodes may be eligible for centralized topology management.

In distributed topology management, each IAB node and IAB donor has a topology management entity and maintains a local topology on each node based on information received from its neighbors.

When an IAB node is powered on, it can access the parent IAB node like a UE. Specifically, the IAB can perform cell selection by utilizing the stored information, and can also search all RF channels in the NR band according to its capabilities to find a suitable cell. Based on the analysis in Section 2.1, IAB cell selection/reselection should take into account many factors such as measurement results, number of backhaul hops to the donor IAB and load conditions. To assist an IAB node in selecting a suitable parent IAB node, the information required for selection/re-selection of an IAB cell, such as IAB indication, donor IAB indication, number of backhaul hops to the IAB donor, and traffic load status of intermediate IAB nodes along that IAB node The data forwarding path can be broadcast by each IAB node. Then, the IAB node MT part can select the parent node based on a specific algorithm and take the above parameters as input.

For distributed topology management, information required for IAB cell selection/reselection can be broadcast, such as IAB indication, donor IAB indication, number of backhaul hops to the IAB donor, and traffic load status data forwarding paths of intermediate IAB nodes along that IAB node.

further more,

For IAB node reselection, it is also processed in the following ways:

Perform topology adjustments for physically fixed repeaters for reliable operation, such as mitigating congestion and load changes on the backhaul link. Based on IAB donor reselection and next-hop IAB node reselection, the processes are as follows.

(1) Donor IAB reselection

Step 0: The IAB node is configured by the serving IAB Donor 1 to report information, such as measurement results of candidate backhaul links between the IAB node and neighboring IAB donors.

Step 1: The IAB node reports auxiliary information (eg measurement results) to the service donor IAB.

Step 2: Once the source donor IAB decides to handover based on the measurement results, the source donor IAB sends a backhaul handover request to the target donor IAB.

Step 3: If the resources in the target IAB donor are available, the target IAB donor will reply ACK to the source IAB donor.

Step 4: The source IAB donor sends a backhaul handover command to the IAB node.

Step 5: Once the backhaul handover command message is received, the IAB node will connect to the target IAB donor.

Step 6: After the IAB node is successfully connected, the target IAB donor transmits the complete backhaul switch to the source IAB donor.

The above CP procedure for donor IAB re-selection is similar to the handover procedure.

(2) Next-hop IAB node reselection

Assume that both IAB Node 1 and IAB Node 2 are located within the coverage area of the IAB donor. However, IAB Node 3 is beyond the coverage of the donor IAB. Therefore, IAB Node 3 is connected to the IAB Donor relayed by IAB Node 1 or IAB Node 2 .

Step 0: The in-service IAB donor configures the IAB node (eg, IAB node 3) to report information such as measurement results, delay or load information.

Step 1: The IAB node reports auxiliary information, such as the measurement results of the backhaul links related to IAB node2 and IAB node3.

Step 2: Once the IAB donor decides to perform an IAB node handover, the IAB donor sends a backhaul handover request to the target IAB node 2.

Step 3: The target IAB node 2 replies an ACK to the IAB donor.

Step 4: The IAB donor sends a backhaul handover command to the IAB node 3 relayed by the IAB node 1. FFS: The content of the backhaul switching command is transparent to IAB node1.

Step 5: After the IAB node 3 receives the backhaul handover command message, it connects to the target IAB node 2.

Step 6: After the IAB node 3 is successfully connected, the target IAB node 2 will send the complete backhaul exchange to the donor IAB.

Step 7: The IAB donor transmits the backhaul release to the IAB node 1.

In step 1, the IAB node will report some information to help the in-service donor IAB make a decision. The following information will be helpful to the donor IAB.

- Measurement results of the link between IAB node 3 and the candidate IAB node

- Delay information for candidate IAB nodes (eg IAB Node 1 and IAB Node 2)

- Loading information for candidate IAB nodes (eg IAB Node 1 and IAB Node 2)

In the case of IAB node reselection, the IAB node shall report auxiliary information including measurement results, latency information and load information to the donor IAB.

The above are only optional embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes, combinations or modifications made to the above embodiments according to the technical essence of the present invention still belong to The protection scope of the technical solution of the present invention.

Those of ordinary skill in the art can understand that all or part of the steps in the above method can be completed by instructing relevant hardware (such as a processor) through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a magnetic disk or an optical disk Wait. Optionally, all or part of the steps in the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above-mentioned embodiments may be implemented in the form of hardware, for example, an integrated circuit to implement its corresponding function, or it may be implemented in the form of a software function module, for example, a processor executes a function stored in a memory. program/instruction to achieve its corresponding function. The present invention is not limited to any particular form of combination of hardware and software.

Although the embodiments disclosed in the present application are as above, the described contents are only the embodiments adopted to facilitate understanding of the present application, and are not intended to limit the present application, such as specific implementation methods in the embodiments of the present invention. Any person skilled in the art to which this application belongs, without departing from the spirit and scope disclosed in this application, can make any modifications and changes in the form and details of the implementation, but the scope of patent protection of this application must still be The scope defined by the appended claims shall prevail.

The above are the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. The node selection method of integrated access and backhaul system, the integrated access and backhaul IAB system is deployed in new wireless NR, uses large-scale MIMO system with multiple input multiple output, including multiple IAB nodes, wherein part is donor IAB node, needs to enhance LTE RRC signaling to support control signaling required by IAB node integration process to dynamically switch backhaul link, and the IAB node supports multiplexing access link and backhaul link in TDM, FDM and SDM with half-duplex constraint, characterized in that, it includes:

   when the IAB node performs cell selection/reselection, the IAB node with the lower number of hops back to the IAB donor should have a higher priority and the load of the IAB node should be lower.
2. 2. The selection method of claim 1, further comprising donor IAB reselection, wherein,

   step 0: the IAB node is configured by the serving IAB donor 1 to report information, measurements of candidate backhaul links between the IAB node and neighboring IAB donors,

   step 1: the IAB node reports the assistance information to the serving donor IAB,

   , the source donor IAB decides to handover based on the measurement, the source donor IAB sends a backhaul handover request to the target donor IAB,

   and step 3: if resources in the target IAB donor are available, the target IAB donor will reply ACK to the source IAB donor, step 4: the source IAB donor sends a backhaul handover command to the IAB node,

   , upon receiving the backhaul handover command message, the IAB node will connect to the target IAB donor,

   step 6: after the IAB node is successfully connected, the target IAB donor transmits the complete backhaul switch to the source IAB donor.
3. 3. The selection method of any of claims 1-2, further comprising a next hop IAB node reselection, wherein,

   IAB node1 and IAB node2 are both within the coverage of the IAB donor, but IAB node3 is out of the coverage of the donor IAB, and therefore IAB node3 is connected to the IAB donor relayed by either IAB node1 or IAB node2,

   step 0: the serving IAB donor configures the IAB node to report information, measurement results, delay or load information, step 1: the IAB node reports assistance information, measurements of backhaul links related to IAB node2 and IAB node3,

   , once the IAB donor decides to perform an IAB node switch, the IAB donor sends a backhaul handover request to the target IAB node2,

   and step 3: the target IAB node2 replies an ACK to the IAB donor,

   and 4, step 4: the IAB donor sends a backhaul handover command to the IAB node3 relayed by the IAB node1, FFS: the contents of the backhaul handover command are transparent to IAB node1,

   and 5: after receiving the backhaul handover command message, the IAB node3 connects to the target IAB node2,

   step 6: after successful connection of IAB node3, the target IAB node2 will send the full backhaul switch to the donor IAB,

   and 7: the IAB donor communicates the backhaul release to IAB node1,

   in step 1, the IAB node will report information to help the serving donor IAB make its decision, the following information will help the donor IAB,

   measurement of the link between IAB node3 and the candidate IAB node, or

   Delay information of candidate IAB nodes, or

   -loading information of candidate IAB nodes;

   in case of IAB node reselection, the IAB node should report side information including measurement results, latency information and load information to the donor IAB.
4. 4. The selection method of claim 3, wherein slot boundaries of the IAB node and donor IAB node should be aligned with integer multiple symbol shifts.
5. 5. The selection method of claim 4, wherein the IAB node topology management is of two types: centralized topology management and distributed topology management; in centralized topology management, the topology of the entire IAB network is managed by a centralized entity, which maintains the global topology of the IAB network; the centralized entity is located on a donor IAB, a core network or an application server; in distributed topology management, each IAB node and IAB donor has its own topology management entity and maintains a local topology based on the exchange of information with neighboring nodes.
6. The node selection device of integrated access and backhaul system deployed in new wireless NR, using massive multiple input multiple output MIMO system, including multiple IAB nodes, wherein part is donor IAB node, control signaling required for enhancing LTE RRC signaling to support IAB node integration process to dynamically switch backhaul link, IAB node supporting multiplexing access link and backhaul link in TDM, FDM and SDM with half-duplex constraint, characterized in that it comprises:

   selection means for, when the IAB node performs cell selection/reselection, the IAB node with a smaller number of hops back to the IAB donor should have a higher priority and the load of the IAB node should be lower.
7. 7. The selection apparatus of claim 6, further comprising donor IAB reselection apparatus to perform the steps of, wherein,

   step 0: the IAB node is configured by the serving IAB donor 1 to report information, measurements of candidate backhaul links between the IAB node and neighboring IAB donors,

   step 1: the IAB node reports the assistance information to the serving donor IAB,

   , the source donor IAB decides to handover based on the measurement, the source donor IAB sends a backhaul handover request to the target donor IAB,

   and step 3: if resources in the target IAB donor are available, the target IAB donor will reply ACK to the source IAB donor, step 4: the source IAB donor sends a backhaul handover command to the IAB node,

   , upon receiving the backhaul handover command message, the IAB node will connect to the target IAB donor,

   step 6: after the IAB node is successfully connected, the target IAB donor transmits the complete backhaul switch to the source IAB donor.
8. 8. The selection apparatus according to any of the claims 6-7, , further comprising a down hop IAB node reselection apparatus to perform the steps, wherein,

   IAB node1 and IAB node2 are both within the coverage of the IAB donor, but IAB node3 is out of the coverage of the donor IAB, and therefore IAB node3 is connected to the IAB donor relayed by either IAB node1 or IAB node2,

   step 0: the serving IAB donor configures the IAB node to report information, measurement results, delay or load information, step 1: the IAB node reports assistance information, measurements of backhaul links related to IAB node2 and IAB node3,

   , once the IAB donor decides to perform an IAB node switch, the IAB donor sends a backhaul handover request to the target IAB node2,

   and step 3: the target IAB node2 replies an ACK to the IAB donor,

   and 4, step 4: the IAB donor sends a backhaul handover command to the IAB node3 relayed by the IAB node1, FFS: the contents of the backhaul handover command are transparent to IAB node1,

   and 5: after receiving the backhaul handover command message, the IAB node3 connects to the target IAB node2,

   step 6: after successful connection of IAB node3, the target IAB node2 will send the full backhaul switch to the donor IAB,

   and 7: the IAB donor communicates the backhaul release to IAB node1,

   in step 1, the IAB node will report information to help the serving donor IAB make its decision, the following information will help the donor IAB,

   measurement of the link between IAB node3 and the candidate IAB node, or

   Delay information of candidate IAB nodes, or

   -loading information of candidate IAB nodes;

   in case of IAB node reselection, the IAB node should report side information including measurement results, latency information and load information to the donor IAB.
9. 9. The selection apparatus of claim 8, wherein slot boundaries of the IAB node and donor IAB node should be aligned with integer multiple symbol shifts.
10. 10. The selection apparatus of claim 9, wherein the IAB node topology management is of two types: centralized topology management and distributed topology management; in centralized topology management, the topology of the entire IAB network is managed by a centralized entity, which maintains the global topology of the IAB network; the centralized entity is located on a donor IAB, a core network or an application server; in distributed topology management, each IAB node and IAB donor has its own topology management entity and maintains a local topology based on the exchange of information with neighboring nodes.

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