Multicast broadcast service reception availability
Multicast Broadcast Services (“MBS”) is a service provided to user equipment (“UE”) devices. As the UE moves through the network, it may switch between network cells. Some network cells include MBS service availability, which will be considered by the UE when selecting cells. MBS service continuity can be maintained when the UE considers MBS service availability for selecting network cells. The service availability of MBS can be determined by the UE while the UE is in an inactive or idle state.
1 . A method for service continuity of a multicast broadcast service (“MBS”) performed by a user equipment (“UE”) in a wireless network, the method comprising:
receiving control information, the control information comprising a service area information, a frequency information, a cell information, and an association between the service area information, the frequency information, and the cell information;
determining a service availability for the MBS based on the control information;
receiving, when the UE has reselected a cell which provides a UE interested MBS service, the MBS service based on a last valid MBS resource allocation configuration received before the cell reselection, wherein the UE continues using the last valid MBS resource allocation configuration to receive the MBS service without receiving a new MBS resource allocation configuration from the reselected cell, the last valid MBS resource allocation configuration is within a same modification period from a moment the UE received the configuration in a previous cell until the UE has successfully reselected a new cell, and the UE monitors a multicast control channel (MCCH) in a next repetition period or modification period; and
avoiding performing packet data convergence protocol (“PDCP”) re-establishment at cell change.
2 . The method of claim 1 , wherein the service area information is a service area identity (“SAI”) list, the cell information is a physical cell identification (“PCI”) list, the frequency information is an absolute radio frequency channel number, and the association indicates that cells identified by the PCI list on the associated frequency belong to an associated SAI.
3 . The method of claim 2 , further comprising:
receiving a user service description (“USD”) from a service layer;
determining whether a service is available in specific cells on specific frequencies based on whether the SAI associated with the UE interested MBS service indicated in the USD is also indicated in an access layer control information; and
considering whether the UE interested MBS service is available in the cells on a frequency associated with the SAI.
4 . The method of claim 1 , further comprising:
selecting, during a priority handling in cell reselection, a cell from a plurality of cells based on awareness of the service availability for the MBS in the cells on specific frequencies,
wherein the frequency on which the UE interested MBS service is available is considered to be a highest frequency.
5 . The method of claim 1 , wherein the cell reselection is based on a cell ranking that includes an offset for MBS that is added to the cell-ranking criterion for cells on which the MBS service is available.
6 . The method of claim 1 , wherein the control information is received from one or more system information blocks (“SIB”) and part of the control information is in the one or more SIBs, and part of the control information is in a multicast control channel (“MCCH”).
7 . A method for service continuity of a multicast broadcast service (“MBS”) performed by a network element in a wireless network, the method comprising:
providing control information over an access layer, wherein the control information comprises a service area information, a frequency information, a cell information, and an association between the service area information, the frequency information, and the cell information, wherein:
the control information is used by a user equipment (UE) to determine a service availability for the MBS; and
sending, when the UE has reselected a cell which provides a UE interested MBS service, the MBS service based on a last valid MBS resource allocation configuration sent before the cell reselection, wherein the UE is configured to avoid performing data convergence protocol (“PDCP”) re-establishment at cell change, and the UE continues using the last valid MBS resource allocation configuration to receive the MBS service without receiving a new MBS resource allocation configuration from the reselected cell, and wherein the last valid MBS resource allocation configuration is within a same modification period from a moment the UE received the configuration in a previous cell until the UE has successfully reselected a new cell, and the UE monitors a multicast control channel (MCCH) in a next repetition period or modification period.
8 . The method of claim 7 , wherein the control information is provided in one or more system information blocks (“SIB”), wherein part of the control information is in the one or more SIBs, and part of the control information is in a multicast control channel (“MCCH”).
9 . The method of claim 7 , wherein the selecting is based on a cell ranking, and the cell ranking includes an offset for MBS.
10 . The method of claim 9 , wherein the offset is configured to the UE with the control information, or in a separate system information blocks (“SIB”), further wherein the service area information is received on an Radio Resource Control (“RRC”) release signaling or on a multicast control channel (“MCCH”).
11 . A method for service continuity of a multicast broadcast service (“MBS”) performed by a user equipment (“UE”) in a wireless network, the method comprising:
receiving a service area information of the MBS;
determining a service availability for the MBS based on the service area information;
receiving, when the UE has reselected a cell belonging to a configured service area, a MBS service based on a last valid MBS resource allocation configuration received before the cell reselection, wherein the UE continues using the last valid MBS resource allocation configuration to receive the MBS service without receiving a new MBS resource allocation configuration from the reselected cell, the last valid MBS resource allocation configuration is within a same modification period from a moment the UE received the configuration in a previous cell until the UE has successfully reselected a new cell, and the UE monitors a multicast control channel (MCCH) in a next repetition period or modification period; and
avoiding performing packet data convergence protocol (“PDCP”) re-establishment at cell change.
12 . The method of claim 11 , wherein the service area information of the MBS is a physical cell identification (“PCI”) list with frequency information associated with each PCI, which indicates that MBS service is available on such cell on the associated frequency.
13 . The method of claim 11 , wherein the UE handles a cell reselection procedure for selecting from a plurality of cells based on the MBS service availability in the cells on the associated frequency.
14 . The method of claim 13 , further comprising:
considering, during a priority handling in cell reselection, a frequency on which the UE interested MBS service is available to be a highest frequency.
15 . The method of claim 13 , wherein the cell reselection is based on a cell ranking that includes an offset for MBS that is added to a cell-ranking criterion for cells on which the MBS service is available.
16 . The method of claim 11 , further comprising:
checking whether a reselected cell belongs to service area information based on the information provided in the reselected cell.
17 . The method of claim 16 , wherein MBS service area identification that can identify an MBS area in RAN (“MAIR”) is broadcast in the reselected cell in one or more system information blocks (“SIB”) or in a multicast control channel (“MCCH”).
18 . The method of claim 11 , wherein when the UE has not reselected a cell, the method comprises:
initiating Radio Resource Control (“RRC”) resume with a cause value indicating a failure of MBS service continuity.