Communication control method
A communication control method according to the first aspect is a method of using a relay apparatus configured to relay communication between an upper apparatus and a lower apparatus by radio. The communication control method includes a step of, in the relay apparatus, reporting, by a user equipment function unit connecting to the upper apparatus by radio, state information to a base station function unit connecting to the lower apparatus by radio. The state information is information indicating at least one state of an RRC state of the user equipment function unit or a radio link state between the upper apparatus and the user equipment function unit.
1 . A method used in a first Integrated Access and Backhaul (IAB) node, the method comprising:
receiving from a network, by the first IAB node, configuration information configuring conditional handover to the first IAB node, the conditional handover being a handover to be executed by the first IAB node in response to a trigger condition being satisfied;
receiving, by the first IAB node, from a second IAB node which connects to the first IAB node as an upper apparatus of the first IAB node and connects to a third IAB node as a lower apparatus of the third IAB node, a Radio Link Failure (RLF) notification indicating deterioration of a radio link between the second IAB node and the third IAB node, wherein the RLF notification is a control signal of a layer lower than a Radio Resource Control (RRC) layer; and
executing, by the first IAB node, the conditional handover from the second IAB node to another IAB node, in response to the reception of the RLF notification, wherein
the trigger condition is an event indicating radio quality deterioration of a serving cell of the first IAB node, the serving cell being managed by the second IAB node, and
the executing the conditional handover comprises executing the configured conditional handover in response to the reception of the RLF notification without transmitting measurement report from the first IAB node.
2 . A first Integrated Access and Backhaul (IAB) node comprising:
a processor and a memory, the processor configured to
receive from a network, configuration information configuring conditional handover to the first IAB node, the conditional handover being a handover to be executed by the first IAB node in response to a trigger condition being satisfied,
receive from a second IAB node which connects to the first IAB node as an upper apparatus of the first IAB node and connects to a third IAB node as a lower apparatus of the third IAB node, a Radio Link Failure (RLF) notification indicating deterioration of a radio link between the second IAB node and the third IAB node wherein the RLF notification is a control signal of a layer lower than a Radio Resource Control (RRC) layer, and
execute the conditional handover from the second IAB node to another IAB node, in response to the reception of the RLF notification, wherein
the trigger condition is an event indicating radio quality deterioration of a serving cell of the first IAB node, the serving cell being managed by the second IAB node, and
the processor is configured to execute the configured conditional handover in response to the reception of the RLF notification without transmitting measurement report from the first IAB node.
3 . A chipset for controlling a first Integrated Access and Backhaul (IAB) node, the chipset comprising:
a processor and a memory, the processor configured to
receive from a network, configuration information configuring conditional handover to the first IAB node, the conditional handover being a handover to be executed by the first IAB node in response to a trigger condition being satisfied,
receive from a second IAB node which connects to the first IAB node as an upper apparatus of the first IAB node and connects to a third IAB node as a lower apparatus of the third IAB node, a Radio Link Failure (RLF) notification indicating deterioration of a radio link between the second IAB node and the third IAB node, wherein the RLF notification is a control signal of a layer lower than a Radio Resource Control (RRC) layer, and
execute the conditional handover from the second IAB node to another IAB node in response to the reception of the RLF notification, wherein
the trigger condition is an event indicating radio quality deterioration of a serving cell of the first IAB node, the serving cell being managed by the second IAB node, and
the processor is configured to execute the configured conditional handover in response to the reception of the RLE notification without transmitting measurement report from the first IAB node.
4 . A non-transitory computer-readable medium comprising, stored thereupon, computer program instructions for execution by a first Integrated Access and Backhaul (IAB) node, the computer program instructions being configured to cause the first IAB node to execute processing of:
receiving from a network, configuration information configuring conditional handover to the first IAB node, the conditional handover being a handover to be executed by the first IAB node in response to a trigger condition being satisfied,
receiving from a second IAB node which connects to the first IAB node as an upper apparatus of the first IAB node and connects to a third IAB node as a lower apparatus of the third IAB node, a Radio Link Failure (RLF) notification indicating deterioration of a radio link between the second IAB node and the third IAB node, wherein the RLF notification is a control signal of a layer lower than a Radio Resource Control (RRC) layer; and
executing the conditional handover from the second IAB node to another IAB node in response to the reception of the RLF notification, wherein
the trigger condition is an event indicating radio quality deterioration of a serving cell of the first IAB node, the serving cell being managed by the second IAB node, and
the executing the conditional handover comprises executing the configured conditional handover in response to the reception of the RLE notification without transmitting measurement report from the first IAB node.
5 . A system comprising:
a first Integrated Access and Backhaul (IAB) node, wherein
the first IAB node is configured to:
receive from a network, configuration information configuring conditional handover to the first IAB node, the conditional handover being a handover to be executed by the first IAB node in response to a trigger condition being satisfied,
receive from a second IAB node which connects to the first IAB node as an upper apparatus of the first IAB node and connects to a third IAB node as a lower apparatus of the third IAB node, a Radio Link Failure (RLF) notification indicating deterioration of a radio link between the second IAB node and the third IAB node, wherein the RLF notification is a control signal of a layer lower than a Radio Resource Control (RRC) layer, and
execute the conditional handover from the second IAB node to another IAB node in response to the reception of the RLF notification, wherein
the trigger condition is an event indicating radio quality deterioration of a serving cell of the first IAB node, the serving cell being managed by the second IAB node, and
the first IAB node is configured to execute the configured conditional handover in response to the reception of the RLE notification without transmitting measurement report from the first IAB node.
6 . The method according to claim 1 , wherein
executing the conditional handover comprises executing the configured conditional handover in response to the reception of the notification, even if the configured trigger condition is not satisfied.