US-12621743-B2 - Method and relay node

Abstract

A method according to a first aspect is a method performed by a relay node that establishes a radio backhaul link, with an adjacent relay node, relaying communication between a user equipment and a donor base station. The method includes measuring a parameter related to communication quality of a data packet by a BAP entity that transmits or receives the data packet via the radio backhaul link, and reporting a result of the measuring to the donor base station by an upper entity locating in an upper layer than the BAP entity.

Inventors

• Masato Fujishiro

Assignees

• KYOCERA CORPORATION

Dates

Publication Date

20260505

Application Date

20220927

Priority Date

20200327

Claims (13)

1. 1 . A method performed by a relay node, the relay node establishing a radio backhaul link, with an adjacent relay node, configured to relay communication between a user equipment and a donor base station, the method comprising: measuring, by a Backhaul Adaptation Protocol (BAP) entity, a parameter related to communication quality of a data packet, the BAP entity being configured to transmit or receive the data packet via the radio backhaul link; and reporting, by an upper entity, a result of the measuring to the donor base station, the upper entity being located in an upper layer than the BAP entity, wherein the measuring comprises measuring for each of a plurality of Quality of Service (QoS) flows established between the user equipment and a core network, the parameter for a data packet belonging to the each of the QoS flows, and the reporting comprises transmitting by the upper layer to the donor base station, a measurement report including a plurality of QoS identifiers that each identifies one of the plurality of QoS flows and a measurement result of the parameter of the corresponding QoS flow.
2. 2 . The method according to claim 1 , further comprising relaying, by the relay node, communication between at least one of a plurality of user equipments and the donor base station, wherein the measuring comprises measuring, for each of the plurality of user equipments, the parameter for a data packet belonging to the each of the user equipments, and the reporting comprises reporting a result of the measuring for each of the plurality of user equipments to the donor base station.
3. 3 . The method according to claim 1 , further comprising receiving, by the relay node and from the donor base station, routing configuration information configured to configure a plurality of relay routes, wherein the plurality of relay routes pass through the relay node and are configured between a different relay node and the donor base station, the different relay node comprising a radio access link with the user equipment, the measuring comprises measuring, for each of the plurality of relay routes, the parameter for a data packet relayed through the each of the relay route, and the reporting comprises reporting a result of the measuring for each of the plurality of relay routes to the donor base station.
4. 4 . The method according to claim 1 , wherein the parameter comprises transmission delay that occurs in transmitting a data packet to the adjacent relay node via the radio backhaul link, the transmission delay is a period of time from a first time point when the data packet reaches the BAP entity to a second time point, and the second time point is a time point when a Medium Access Control (MAC) entity of the relay node receives, from the adjacent relay node, information indicating that reception of the data packet is successful.
5. 5 . The method according to claim 1 , wherein the parameter comprises processing delay that occurs, at the BAP entity, in transmitting a data packet to the adjacent relay node via the radio backhaul link, and the processing delay is a period of time from a time point when the data packet reaches the BAP entity to a time point when a Radio Link Control (RLC) entity of the relay node receives the data packet.
6. 6 . The method according to claim 1 , wherein the parameter comprises a parameter related to the number of discards that is the number of data packets discarded, at the BAP entity, in transmitting a plurality of data packets to the adjacent relay node via the radio backhaul link.
7. 7 . The method according to claim 6 , further comprising measuring, by the BAP entity, the number of discards per reason for discarding the data packet, wherein the reporting comprises reporting a parameter related to the number of discards measured per the reason to the donor base station.
8. 8 . The method according to claim 1 , wherein the parameter comprises a parameter related to the number of data packets where the adjacent relay node fails to receive among a plurality of data packets transmitted to the adjacent relay node via the radio backhaul link.
9. 9 . The method according to claim 1 , further comprising: establishing, by the relay node, the radio backhaul link with at least one of a plurality of adjacent relay nodes; receiving, by the relay node and from the donor base station, routing configuration information configured to configure a relay route passing through each of the plurality of adjacent relay nodes; and performing, by the BAP entity, rerouting, the rerouting allowing a data packet where a relay route is specified to be transmitted via a radio backhaul link corresponding to a relay route different from the specified relay route, wherein the parameter comprises a parameter related to the number of rerouting counts that is the number of data packets where the rerouting is performed at the BAP entity.
10. 10 . The method according to claim 9 , further comprising measuring, by the BAP entity, the number of rerouting counts per reason for the rerouting, wherein the reporting comprises reporting a parameter related to the number of rerouting counts measured per the reason to the donor base station.
11. 11 . The method according to claim 8 , further comprising: receiving, by the relay node, a plurality of Packet Data Convergence Protocol (PDCP) data packets transmitted from the adjacent relay node with PDCP sequence numbers being consecutive, wherein the parameter comprises a parameter related to the number of missing PDCP sequence numbers among the plurality of data packets.
12. 12 . The method according to claim 1 , further comprising receiving, by the relay node and from the donor base station, configuration information configured to configure measurement of the parameter, wherein the measuring comprises a step of measuring the parameter based on the configuration information.
13. 13 . A relay node configured to establish a radio backhaul link, with an adjacent relay node, configured to relay communication between a user equipment and a donor base station, the relay node comprising: a Backhaul Adaptation Protocol (BAP) entity configured to transmit or receive a data packet via the radio backhaul link; and an upper entity located in an upper layer than the BAP entity, wherein the BAP entity performs measurement of a parameter related to communication quality of the data packet, and the upper entity reports a result of the measurement to the donor base station, wherein the measurement comprises a measurement for each of a plurality of Quality of Service (QoS) flows established between the user equipment and a core network, the parameter for a data packet belonging to the each of the QoS flows, and the upper entity reports the result by transmitting by the upper layer to the donor base station, a measurement report including a plurality of QoS identifiers that each identifies one of the plurality of QoS flows and a measurement result of the parameter of the corresponding QoS flow.

Description

RELATED APPLICATIONS The present application is a continuation based on PCT Application No. PCT/JP2021/008638, filed on Mar. 5, 2021, which claims the benefit of Japanese Patent Application No. 2020-057444 filed on Mar. 27, 2020. The content of which is incorporated by reference herein in their entirety. TECHNICAL FIELD The present disclosure relates to a method, a relay node, and a communication node used in a mobile communication system. BACKGROUND ART In the 3rd Generation Partnership Project (3GPP), which is a standardization project of a mobile communication system, a new relay node referred to as an Integrated Access and Backhaul (IAB) node has been under study. One or a plurality of relay nodes are located between a user equipment and a donor base station. The relay node establishes a radio backhaul link with another relay node or the donor base station to perform relay for communication between the user equipment and the donor base station via the radio backhaul link. The 3GPP defines Minimization of Drive Test (MDT), which is a technique for optimizing a network configuration by using results of communication quality measurement performed in a base station or a user equipment. Examples of such communication quality measurement include packet loss measurement, packet delay measurement, and the like (see NPL 1, for example). CITATION LIST Non-Patent Literature NPL 1: 3GPP Technical specification “TS36.314 V15.2.0” December 2018 SUMMARY OF INVENTION A method according to a first aspect is a method performed by a relay node that establishes a radio backhaul link, with an adjacent relay node, relaying communication between a user equipment and a donor base station. The method includes measuring a parameter related to communication quality of a data packet by a Backhaul Adaptation Protocol (BAP) entity that transmits or receives the data packet via the radio backhaul link, and reporting a result of the measuring to the donor base station by an upper entity located in an upper layer than the BAP entity. A method according to a second aspect is a method performed by a communication node. The method includes transmitting or receiving a data packet to a different communication node or from the different communication node by using a first radio resource belonging to a first cell group and a second radio resource belonging to a second cell group, and measuring a first parameter related to communication quality of a data packet transmitted or received using the first radio resource, and a second parameter related to communication quality of a data packet transmitted or received using the second radio resource. A relay node according to a third aspect is a relay node that establishes a radio backhaul link with an adjacent relay node, relaying communication between a user equipment and a donor base station. The relay node includes a Backhaul Adaptation Protocol (BAP) entity that transmits or receives a data packet via the radio backhaul link, and an upper entity located in an upper layer than the BAP entity, in which the BAP entity performs measurement of a parameter related to communication quality of the data packet, and the upper entity reports a result of the measurement to the donor base station. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating a configuration of a mobile communication system 1 according to an embodiment. FIG. 2 is a diagram illustrating a configuration of a gNB 200. FIG. 3 is a diagram illustrating a configuration of an IAB node 300. FIG. 4 is a diagram illustrating a configuration of a UE 100. FIG. 5 is a diagram illustrating an example of a protocol stack of a user plane. FIG. 6 is a diagram illustrating an example of a protocol stack of a control plane. FIG. 7 is a diagram illustrating an example of the protocol stack of the control plane. FIG. 8 is a diagram illustrating an IAB topology according to an embodiment. FIG. 9 is a diagram illustrating a sequence of an operation example according to an embodiment. DESCRIPTION OF EMBODIMENTS In a case where communication between a user equipment and a donor base station is relayed by one or a plurality of relay nodes, it is desired to implement the communication quality measurement performed in the relay node(s). In view of this, the present disclosure has an object to appropriately measure communication quality for a radio backhaul link of a relay node. A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference signs. Configuration of Mobile Communication System First, a configuration of a mobile communication system according to an embodiment will be described. FIG. 1 is a diagram illustrating a configuration of a mobile communication system 1 according to an embodiment. The mobile communication system 1 is a fifth generation (5G) mobile communication system based on the 3GP