Access network signaling and resource allocation for multicast/broadcast sessions
This disclosure describes an architecture for supporting MBS sessions in a wireless access network. Each of such MBS sessions is flexibly and dynamically delivered by the access network into one or more Point-To-Point (PTP, or unicast) and Point-To-Multipoint (PTM, or multicast) delivery instances. As such, a subset of the UEs participating in the MBS may be configured to receive the MBS session in a PTP-like manner and quality. The architecture further allows for access network level switching of one or more of the UEs participating in the MBS session between the PTP mode and PTM mode. Such switching are effectuated dynamically without involvement of application layer. The resource allocations and configuration for the PTP and PTM delivery instances may be performed in the access network collaboratively between a central unit (CU) and one or more distributed units (DUs). Such collaborative resource allocation and configuration may be effectuated using a novel architecture for the signaling messages between the CU and the DUs.
1 . A method for wireless resource allocation performed by a first access network node (ANN) in communication with a second ANN in a wireless communication network, the first ANN comprising a Distributed Unit (DU), the second ANN comprising a Central Unit (CU), and the method comprising:
receiving, from the second ANN, one or more requests for an establishment, a modification, or a release of resource allocations in the first ANN for transmitting service data of a multicast/broadcast service (MBS) session to a set of user equipments (UEs) in a point-to-point (PTP) delivery mode and/or a point-to-multipoint (PTM) delivery mode and for communicating control information between the first ANN and the second ANN, wherein the first ANN decides a delivery mode for each of the set of UEs as being either the PTP delivery mode, the PTM delivery mode, or both the PTP and PTM delivery modes, and wherein the one or more requests comprise an MBS session identifier; and
establishing the resource allocations in the first ANN based on the one or more requests;
wherein the one or more requests further comprises:
a UE identifier to indicate a target UE of the request and
a separate UE-specific radio bearer (RB) identifier for at least one of the set of RBs for at least one specific UE of the set of UEs.
2 . The method of claim 1 , wherein the one or more requests further comprise a set of RB identifiers for uniquely identifying, along with the MBS session identifier, a set of RBs allocated to Quality of Service (QOS) flows of the MBS session by the second ANN.
3 . The method of claim 2 , wherein the one or more requests further comprise:
a first set of QoS parameters corresponding to each RB in the set of RBs; and
a second set of QoS parameters for each of the QoS flows mapped to the set of RBs.
4 . The method of claim 2 , wherein:
the one or more requests comprise a set of information items; and
the method further comprises establishing, modifying or releasing, by the first ANN, the resource allocations corresponding to a plurality of delivery instances for transmission of MBS session protocol data unit (PDUs) of the MBS session based on the set of information items.
5 . The method of claim 4 , wherein each of the plurality of delivery instances is either a PTP delivery instance or a PTM delivery instance.
6 . The method of the claim 2 , further comprising:
determining a downlink data tunnel information for receiving PDCP PDU associated with an RB at the first ANN;
including the downlink data tunnel information in configuration information for transmission to the second ANN; and
receiving the PDCP PDU associated with the RB from the second ANN according to the downlink data tunnel information.
7 . The method of the claim 2 , wherein the one or more requests further comprises a retransmission activation indication associated with a UE of the set of UEs and associated with an RB of the set of RBs.
8 . The method of claim 7 , further comprising:
establishing an RLC entity for an RB associated with a PTP instance for a UE by the first ANN, wherein the RLC entity is associated with a first data tunnel for transmitting a PDCP PDU associated with the RB from the second ANN to the first ANN.
9 . A first access network node (ANN) comprising a memory for storing computer instructions and a processor in communication with the memory, wherein, when the processor executes the computer instructions, the processor is configured to cause the first ANN to:
receive, from a second ANN comprising a Central Unit (CU), one or more requests for an establishment, a modification, or a release of resource allocations in the first ANN for transmitting service data of a multicast/broadcast service (MBS) session to a set of user equipments (UEs) in a point-to-point (PTP) delivery mode and/or a point-to-multipoint (PTM) delivery mode and for communicating control information between the first ANN and the second ANN, wherein the first ANN comprises a Distributed Unit (DU) and decides a delivery mode for each of the set of UEs as being either the PTP delivery mode, the PTM delivery mode, or both the PTP and PTM delivery modes, and wherein the one or more requests comprise an MBS session identifier; and
establish the resource allocations in the first ANN based on the one or more requests, wherein the one or more requests further comprises:
a UE identifier to indicate a target UE of the request, and
a separate UE-specific radio bearer (RB) identifier for at least one of the set of RBs for at least one specific UE of the set of UEs.
10 . The first ANN of claim 9 , wherein the one or more requests further comprise a set of RB identifiers for uniquely identifying, along with the MBS session identifier, a set of RBs allocated to Quality of Service (QOS) flows of the MBS session by the second ANN.
11 . The first ANN of claim 10 , wherein the one or more requests further comprise:
a first set of QoS parameters corresponding to each RB in the set of RBs; and
a second set of QOS parameters for each of the QoS flows mapped to the set of RBs.
12 . The first ANN of claim 10 , wherein:
the one or more requests comprise a set of information items; and
when the processor executes the computer instructions, the processor is configured to further cause the first ANN to establish, modify or release the resource allocations corresponding to a plurality of delivery instances for transmission of MBS session protocol data unit (PDUs) of the MBS session based on the set of information items.
13 . The first ANN of claim 12 , wherein each of the plurality of delivery instances is either a PTP delivery instance or a PTM delivery instance.
14 . A non-transitory storage medium for storing computer readable instructions, the computer readable instructions, when executed by a processor of a first access network node (ANN), causing the processor to:
receive, from a second ANN comprising a Central Unit (CU), one or more requests for an establishment, a modification, or a release of resource allocations in the first ANN for transmitting service data of a multicast/broadcast service (MBS) session to a set of user equipments (UEs) in a point-to-point (PTP) delivery mode and/or a point-to-multipoint (PTM) delivery mode and for communicating control information between the first ANN and the second ANN, wherein the first ANN comprises a Distributed Unit (DU) decides a delivery mode for each of the set of UEs as being either the PTP delivery mode, the PTM delivery mode, or both the PTP and PTM delivery modes, and wherein the one or more requests comprise an MBS session identifier; and
establish the resource allocations in the first ANN based on the one or more requests, wherein the one or more requests further comprises:
a UE identifier to indicate a target UE of the request, and
a separate UE-specific radio bearer (RB) identifier for at least one of the set of RBs for at least one specific UE of the set of UEs.
15 . The non-transitory storage medium of claim 14 , wherein the one or more requests further comprise a set of RB identifiers for uniquely identifying, along with the MBS session identifier, a set of RBs allocated to Quality of Service (QOS) flows of the MBS session by the second ANN.
16 . The non-transitory storage medium of claim 15 , wherein the one or more requests further comprise:
a first set of QoS parameters corresponding to each RB in the set of RBs; and
a second set of QOS parameters for each of the QoS flows mapped to the set of RBs.
17 . The non-transitory storage medium of claim 15 , wherein:
the one or more requests comprise a set of information items; and
the computer readable instructions further cause the processor to establish, modify or release the resource allocations corresponding to a plurality of delivery instances for transmission of MBS session protocol data unit (PDUs) of the MBS session based on the set of information items.
18 . The non-transitory storage medium of claim 17 , wherein each of the plurality of delivery instances is either a PTP delivery instance or a PTM delivery instance.