US-12621745-B2 - Communication control method

US12621745B2US 12621745 B2US12621745 B2US 12621745B2US-12621745-B2

Abstract

In a first aspect, a communication control method is used in a cellular communication system. The communication control method includes receiving, by a relay node involved between a parent node and a child node, a flow control feedback message from the parent node or the child node. The communication control method includes executing, by the relay node, local rerouting to transfer a data packet to an alternative path, which is different from a path to the parent node or the child node transmitting the flow control feedback message, in response to a certain period elapsing after receiving the flow control feedback message.

Inventors

Masato Fujishiro
Henry Chang

Assignees

KYOCERA CORPORATION

Dates

Publication Date: 20260505
Application Date: 20230703

Claims (3)

1 . A communication control method comprising: receiving, by a first relay node from a second relay node, a first indication indicating a failure in a backhaul link; in response to receiving the first indication, executing by the first relay node, first local rerouting to transfer a first data packet to a first alternative path different from a path to the second relay node; after executing the first local rerouting, receiving by the first relay node from the second relay node, a second indication indicating a recovery in the backhaul link; in response to receiving the second indication, transmitting, by the first relay node, a second data packet to the path to the second relay node; receiving, by the first relay node, a flow control feedback message from a child node of the first relay node; and determining, by the first relay node, whether to perform second local rerouting to transfer a third data packet to a second alternative path different from a path to the child node based on specified information included in the flow control feedback message.
2 . A relay node comprising a processor and a memory, the processor configured to: receive from a second relay node, a first indication indicating a failure in a backhaul link, in response to receiving the first indication, execute first local rerouting to transfer a first data packet to a first alternative path different from a path to the second relay node, after executing the first local rerouting, receive from the second relay node, a second indication indicating a recovery in the backhaul link, in response to receiving the second indication, transmit a second data packet to the path to the second relay node; receive a flow control feedback message from a child node of the relay node; and determine whether to perform second local rerouting to transfer a third data packet to a second alternative path different from a path to the child node based on specified information included in the flow control feedback message.
3 . An apparatus configured to control a first relay node, the apparatus comprising a processor and a memory, the processor configured to: receive from a second relay node, a first indication indicating a failure in a backhaul link, in response to receiving the first indication, execute first local rerouting to transfer a first data packet to a first alternative path different from a path to the second relay node, after executing the first local rerouting, receive from the second relay node, a second indication indicating a recovery in the backhaul link, in response to receiving the second indication, transmit a second data packet to the path to the second relay node; receive a flow control feedback message from a child node of the first relay node; and determine whether to perform second local rerouting to transfer a third data packet to a second alternative path different from a path to the child node based on specified information included in the flow control feedback message.

Description

RELATED APPLICATIONS The present application is a continuation based on PCT Application No. PCT/JP2021/047564, filed on Dec. 22, 2021, which claims the benefit of U.S. Provisional Application No. 63/133,490 filed on Jan. 4, 2021. The content of which is incorporated by reference herein in their entirety. TECHNICAL FIELD The present disclosure relates to a communication control method used in a cellular communication system. BACKGROUND OF INVENTION In the 3GPP (Third Generation Partnership Project), which is a project for the standardization of cellular communication systems, introducing a new relay node referred to as an IAB (Integrated Access and Backhaul) node (for example, see “3GPP TS 38.300 V16.3.0 (2020 September)”) is being considered. One or more relay nodes are involved in communication between a base station and a user equipment and perform relay for the communication. SUMMARY In a first aspect, a communication control method is used in a cellular communication system. The communication control method includes receiving, by a relay node involved between a parent node and a child node, a flow control feedback message from the parent node or the child node. The communication control method includes executing, by the relay node, local rerouting to transfer a data packet to an alternative path, the alternative path being different from a path to the parent node or the child node transmitting the flow control feedback message, in response to a certain period elapsing after receiving the flow control feedback message. In a second aspect, a communication control method is used in a cellular communication system. The communication control method includes attempting, by a relay node involved between a parent node and a child node, to transfer a data packet to the parent node or the child node. The communication control method includes executing, by the relay node, local rerouting to transfer the data packet to an alternative path when the relay node fails to transfer the data packet for a certain period, the alternative path being different from a path to the parent node or the child node. In a third aspect, a communication control method is used in a cellular communication system. The communication control method includes executing, by a relay node and in response to at least one of a plurality of execution conditions being satisfied, local rerouting to transfer a data packet to an alternative path, the plurality of execution conditions including receiving a flow control feedback message, receiving an occurrence notification of a failure in a backhaul link between the relay node and a different relay node, and failing to transfer the data packet for a certain period, the alternative path being different from a path to the different relay node. The communication control method includes stopping, by the relay node, the local rerouting in response to a stopping condition being satisfied after executing the local rerouting. In a fourth aspect, a communication control method is used in a cellular communication system. The communication control method includes transmitting, by a donor base station including a first relay node under control of the donor base station, a first message to the first relay node, the first message being related to local rerouting, and performing, by the first relay node, an operation related to the local rerouting in response to receiving the first message. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a configuration example of a cellular communication system according to an embodiment. FIG. 2 is a diagram illustrating a relationship between an IAB node, Parent nodes, and Child nodes. FIG. 3 is a diagram illustrating a configuration example of a gNB (base station) according to an embodiment. FIG. 4 is a diagram illustrating a configuration example of an IAB node (relay node) according to an embodiment. FIG. 5 is a diagram illustrating a configuration example of a UE (user equipment) according to an embodiment. FIG. 6 is a diagram illustrating an example of a protocol stack related to an RRC connection and a NAS connection of an IAB-MT. FIG. 7 is a diagram illustrating an example of a protocol stack related to an F1-U protocol. FIG. 8 is a diagram illustrating an example of a protocol stack related to an F1-C protocol. FIG. 9 is a diagram illustrating an example of local rerouting in a first embodiment. FIG. 10 is a diagram illustrating an example of the local rerouting in the first embodiment. FIG. 11 is a diagram illustrating an operation example of the first embodiment. FIG. 12 is a diagram illustrating an example of local rerouting in a second embodiment. FIG. 13 is a diagram illustrating an example of the local rerouting in the second embodiment. FIG. 14 is a diagram illustrating an operation example in the second embodiment. FIG. 15 is a diagram illustrating an example of local rerouting in a third embodiment. FIG. 16 is a diagram illustrating an example of