Message transmission method, apparatus and system in integrated access and backhaul systems
A message transmission apparatus, applicable to a first integrated access and backhaul node (IAB-node) includes: a receiver configured to: receive a second radio resource control (RRC) reconfiguration message for path migration of a second IAB-node while the first IAB-node is still connected with source parent node, the second radio resource control (RRC) reconfiguration message being transmitted by a donor central unit (donor-CU), the second IAB-node is a downstream child node of the first IAB-node; and receive a first RRC reconfiguration message for path migration of the first IAB-node, the first RRC reconfiguration message being transmitted by the donor-CU; and a transmitter configured to forward, to the second IAB-node, the second RRC reconfiguration message which is withhold until random access of the first IAB-node is successful.
1 . A message transmission apparatus, applicable to a first integrated access and backhaul node (IAB-node), the apparatus comprises:
a receiver configured to:
receive a second radio resource control (RRC) reconfiguration message for path migration of a second IAB-node while the first IAB-node is still connected with source parent node, the second radio resource control (RRC) reconfiguration message being transmitted by a donor central unit (donor-CU), the second IAB-node is a downstream child node of the first IAB-node; and
receive a first RRC reconfiguration message for path migration of the first IAB-node, the first RRC reconfiguration message being transmitted by the donor-CU; and
a transmitter configured to withhold the second RRC reconfiguration message to be forwarded to the second IAB node until the first IAB-node has successfully performed a random access procedure to the target parent node,
wherein the second RRC reconfiguration message is carried by a first downlink F1AP message transmitted by the donor-CU, and
wherein the first RRC reconfiguration message includes a first parameter configured for the first IAB-node to change a transmission path, the first parameter including:
a default backhaul RLC channel configured for the first IAB-node,
a default BAP route configured for the first IAB-node, or
an IP address configured for the first IAB-node.
2 . The apparatus according to claim 1 , wherein the first downlink F1AP message further includes first buffer indication information, the first buffer indication information being used to instruct the first IAB-node to buffer the second RRC reconfiguration message.
3 . The apparatus according to claim 1 , wherein the transmitter is further configured to transmit path migration failure indication information to the second IAB-node when the random access of the first IAB-node fails.
4 . The apparatus according to claim 1 , wherein the first RRC reconfiguration message includes a first parameter configured for the first IAB-node to change a transmission path or first path migration indication information, and the transmitter is further configured to transmit a path migration failure indication information to the second IAB-node.
5 . The apparatus according to claim 1 ,
the transmitter is further configured to transmit, when the random access of first IAB-node is successful, a first RRC reconfiguration complete message to the donor-CU; and
the receiver configured to receive a second RRC reconfiguration complete message transmitted by the second IAB-node.
6 . The apparatus according to claim 5 , wherein the transmitter is further configured to forward, to the Donor-CU, the first RRC reconfiguration complete message including the second RRC reconfiguration complete message.
7 . The apparatus according to claim 6 , wherein
the receiver is further configured to receive the second RRC reconfiguration complete message transmitted by the second IAB-node,
the transmitter is further configured to transmit a third uplink F1AP message containing the second RRC reconfiguration complete message to a mobile terminal (MT) of the first IAB-node.
8 . A message transmission apparatus, applicable to a second integrated access and backhaul node (IAB-node), the apparatus comprises:
a receiver configured to receive a third RRC reconfiguration message for path migration of a third IAB-node from a donor-CU while a first IAB-node is still connected with source parent node; and
a transmitter configured to withhold the third RRC reconfiguration message to be forwarded to the third IAB-node until receiving a second RRC reconfiguration message transmitted by the donor-CU and forwarded by the first IAB-node, the second RRC reconfiguration message being used for path migration of a second IAB-node;
the third IAB-node is a downstream child node of the second IAB-node, and the second IAB-node is a downstream child node of the first IAB-node,
wherein the third RRC reconfiguration message is carried by a second downlink F1AP message transmitted by the Donor-CU, and
wherein when the second RRC reconfiguration message includes a second parameter configured for the second IAB-node to change a transmission path, the second parameter configured for the second IAB-node to change a transmission path including:
a default RLC channel configured for the second IAB-node,
a default BAP routing ID configured for the second IAB-node, or
an IP address configured for the second IAB-node configured for the second IAB-node.
9 . The apparatus according to claim 8 , wherein when the second RRC reconfiguration message contains second path migration indication information, the transmitter transmits the second indication information to the DU of the second IAB-node, the second path migration indication information being used to indicate that the second RRC reconfiguration message is a reconfiguration message for the second IAB-node to perform path migration.
10 . The apparatus according to claim 8 , wherein, wherein the second downlink F1AP message includes second buffer indication information, the second buffer indication information being used to indicate the second IAB-node to buffer the third RRC reconfiguration message.