CN114390442A

CN114390442A - Transmission method and system for multicast broadcast service in NR cell

Info

Publication number: CN114390442A
Application number: CN202011112155.6A
Authority: CN
Inventors: 魏立梅; 袁乃华; 陈迎; 朱玉梅; 周志宏; 范晨
Original assignee: Chengdu TD Tech Ltd
Current assignee: Chengdu TD Tech Ltd
Priority date: 2020-10-16
Filing date: 2020-10-16
Publication date: 2022-04-22
Anticipated expiration: 2040-10-16
Also published as: CN114390442B

Abstract

The invention provides a transmission method and a system of multicast broadcast service in NR cells, which configure activated PTM load and non-activated PTM load for each MBS, configure an activated PTP load or a non-activated PTP load for receiving service UE, configure activated DL BWP for each UE, transmit the service through the activated PTM load and the activated PTP load, dynamically switch between PTM and PTP for each UE in the process of transmitting the service, transmit the service to the UE through corresponding load by signaling interaction between a source cell and a target cell in the process of switching the UE to the target cell, and can ensure that the service can be continuously received through corresponding load when the UE is switched from the source cell to the target cell.

Description

Transmission method and system for multicast broadcast service in NR cell

Technical Field

The present invention relates to wireless communication technologies, and in particular, to a method and a system for transmitting a multicast broadcast service in an NR cell.

Background

With the continuous development of wireless communication technology, New Radio Access (NR) systems have come into people's lives. In order to provide Multicast and Broadcast Service (MBS) in NR cell, Release 17Work Item (R17 WI) was set up in Radio Access Network (RAN) in 3rd Generation Partnership Project (3 GPP) in year 20112, and The total meeting of Radio Access Network (RAN): the NR MBS project.

In NR MBS, it is explicitly required that in the transmission process of MBS, for a given RRC connected UE, under the condition of ensuring the continuity of MBS service, the transmission mode supporting broadcast/multicast service is dynamically switched between PTM and PTP, and at the same time, it is required to ensure the continuous reception of MBS during the UE moving process. However, there is currently no corresponding method to ensure the above requirements.

Disclosure of Invention

In view of the above problems, the present invention provides a method and system for transmitting multicast broadcast service in NR cell.

In a first aspect, the present invention provides a method for transmitting a multicast broadcast service in an NR cell, including:

in each cell transmitting multicast broadcast service MBS, uniformly configuring at least one MBS special bandwidth part BWP and uniformly configuring at least one general BWP for each MBS special BWP, wherein the MBS special BWP is used for transmitting MBS to user equipment UE, the general BWP is used for carrying common service of the UE, and the general BWP includes the MBS special BWP; for a broadcast multicast service, configuring a service data adaptation protocol SDAP entity for the service, wherein the SDAP entity is used for mapping each service quality QOS flow of the service MBS conversation to a radio bearer RB and configuring a packet data convergence protocol PDCP entity for each generated RB; configuring an activated PTM bearer and an inactivated PTM bearer for the service in each cell for transmitting the service, configuring an activated PTP bearer or an inactivated PTP bearer for each RRC connected-state UE for receiving the service, and configuring an activated DL BWP for each RRC connected-state UE for receiving the service; in each cell transmitting the service, a media access control MAC layer receives RLC PDUs of each radio link control protocol RLC entity loaded by each PTM/PTP configured for the MBS through a logic channel; at each cell transmitting the traffic, for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP where the bearer is located; for each RRC connected UE receiving the service, in the transmission process of the service, the MAC layer dynamically switches the transmission mode of the service between the PTM and the PTP; in the transmission process of the service, for each RRC connected state UE receiving the service, in the process that the UE moves from a source cell to a target cell, the service is transmitted to the UE in the target cell through corresponding load bearing through signaling interaction between the source cell and the target cell.

In other optional embodiments, the configuring active PTM bearers and inactive PTM bearers for the service, configuring one active PTP bearer or one inactive PTP bearer for each RRC connected UE receiving the service, and configuring active DL BWP for each RRC connected UE receiving the service includes: determining N configured for the MBS in each cell transmitting the MBS₁An active PTM bearer; when N is present₁>0, when configuring each activated PTM bearer, selecting a BWP from the MBS-dedicated BWPs configured in a unified manner for transmitting the PTM bearer, and configuring PTP bearers for RRC connected UEs receiving the PTM bearer on the selected BWP, where the PTP bearer for each UE is transmitted on the selected BWP, where the PTP bearer for each UE is in an inactive state(ii) a When N is present₁When the current configuration is 0, selecting at least one BWP from the MBS special BWPs which are configured uniformly for configuring PTP load to the RRC connection state UE which receives the service, and recording the selected BWP, wherein the PTP load configured for each UE is in an activated state; in N₁>0, if at least one RRC connected UE receiving the service exists, and the UE cannot receive the service through any activated PTM bearer, excluding BWPs used for transmitting the activated PTM bearer in an MBS dedicated BWP configured in a unified manner, and selecting at least one BWP from the remaining BWPs for configuring PTP bearers for the UE, wherein PTP bearers configured for the UE are in an activated state; number of BWPs N when recorded₃When not 0, configuring a PTM bearer for the service on each recorded BWP, wherein each configured PTM bearer is in an inactive state; configuring activated DL BWP for each RRC connected UE receiving the service through PTM bearer or PTP bearer; configuration information of each PTM bearer, configuration information of each PTP bearer, and DL BWP configuration information of each UE are determined.

In other optional embodiments, the configuration information of the PTM bearer includes basic configuration information of the PTM bearer and BWP configuration information of the PTM bearer; wherein, the basic configuration information of the PTM bearer comprises: the MBS comprises a temporary mobile group identifier TMGI, a session identifier ID, a group radio network temporary identifier G-RNTI, a semi-persistent scheduling group radio network temporary identifier SPS G-RNTI, configuration information of an SDAP entity, configuration information of a PDCP entity, configuration information of an RLC entity and physical layer configuration information; the BWP configuration information of the PTM bearer includes: sending basic parameters of BWP of the PTM bearer, sending configuration information of a control resource CORESET and a search space on the BWP of the PTM bearer and a discontinuous reception DRX mode of the PTM bearer; the configuration information of the PTP bearer comprises basic configuration information of the PTP bearer and BWP configuration information of the PTP bearer; wherein the basic configuration information of the PTP bearer includes: TMGI of the MBS, session ID, configuration information of the SDAP entity, configuration information of the PDCP entity, configuration information of the RLC entity, cell radio network identification C-RNTI of the UE, semi-persistent scheduling cell radio network identification SPS C-RNTI of the UE and physical layer configuration information; the BWP configuration information of the PTP bearer includes: and sending the basic parameters of the BWP of the PTP bearer, sending configuration information of CORESET and a search space on the BWP of the PTP bearer and the DRX mode of the PTP bearer.

In other optional embodiments, in the same cell, each PTM bearer that transmits the MBS service has the same basic configuration information and different BWP configuration information; in different cells, PTM bearers configured for the MBS on the same MBS special BWP have the same basic configuration information and the same BWP configuration information except the DRX mode; for a UE receiving a service, PTP bearers employed on the same MBS-dedicated BWP at different cells have the same basic configuration information and the same BWP configuration information except for DRX mode.

In other optional embodiments, the configuring active PTM bearers and inactive PTM bearers for the service includes: configuring K RLC entities and K SC-MTCHs for the PTM bearer, wherein the K RLC entity is connected with the PDCP entity of the K RB of the service upwards and is connected with the K SC-MTCH downwards; configuring K RLC entities and K DTCHs for PTP load bearing of each UE, wherein the kth RLC entity is connected with the PDCP entity of the kth RB of the service upwards and connected with the kth DTCH downwards; when the kth RLC entity carried by the PTP and the kth RLC entity carried by the PTM on the same BWP adopt the same RLC mode, the kth RLC entity carried by the PTP and the kth RLC entity carried by the PTM have the same RLC parameters; wherein, the RLC mode corresponding to the RLC entity carried by the PTM includes a TM mode or an UM mode; the RLC mode corresponding to the RLC entity of the PTP bearer includes a TM mode, an UM mode, or an AM mode.

In other optional embodiments, for a PTM bearer or PTP bearer in an inactive state, configuring K sets of RLC parameters and K SC-MTCHs or DTCHs; and the kth group of RLC parameters are used for configuring the kth RLC entity of the PTM bearer or the PTP bearer, and the kth SC-MTCH or DTCH corresponds to the PDCP entity of the kth RB.

In other optional embodiments, the RLC entities associated with the RB share a data storage area for storing PDCP PDUs from the PDCP entity of the RB and parameters employed by the respective RLC entities associated with the RB.

In other alternative embodiments, for a PTM or PTP bearer in the inactive state, N is configured₅The group RLC entities, wherein the kth RLC entity in each group of RLC entities is connected with the PDCP entity of the kth RB; wherein N is₅<N₄，N₄Indicating the number of PTM bearers in an inactive state and PTP bearers in an inactive state; slave N when inactive PTM/PTP bearer is activated₅Selecting a group of idle RLC entities from the group RLC entities, and configuring the idle RLC entities to the PTM/PTP bearer in the inactive state; or configuring an RLC entity resource pool, wherein the RLC entity resource pool is composed of at least one RLC entity; when the kth RB in the PTP bearer of one UE is activated, selecting an idle RLC entity from the RLC entity resource pool, configuring the idle RLC entity by using the kth group RLC parameters of the PTP bearer of the UE, connecting the idle RLC entity with the PDCP entity of the kth RB of the service, and connecting the RLC entity with the kth DTCH in the PTP bearer of the UE; when an inactive PTM bearer is activated, K idle RLC entities are selected from the RLC entity resource pool for the PTM bearer, a K-th RLC entity is configured by using a K-th group of RLC parameters of the PTM bearer, the RLC entity is connected with a PDCP entity of a K-th RB of the service, and the RLC entity is connected with a K-th SC-MTCH of the bearer.

In other optional embodiments, for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP on which the bearer is located, including: for each activated PTM bearer, for each RRC connected state UE receiving the PTM bearer, transmitting configuration information of the PTM bearer, configuration information of a PTP bearer configured for the UE and configuration information of DL BWP configured for the UE to the UE through dedicated signaling; determining a SET of beams SET for transmitting the PTM bearer; splitting the PTM bearer into K₁+1 sub-PTM bearers, K₁The number of RBs having a fixed data amount per transmission and having periodic transmission among the RBs generated for the traffic is represented by P-RB, and the data amount per transmission and having periodic transmission is represented by NP-RB tableIndicating other RBs, each P-RB having a sub-PTM bearer for transmitting the P-RB to the UE in a PTM mode, indicating the sub-PTM bearer of the P-RB by the P-PTM bearer, and the rest sub-PTM bearers for transmitting other (K-K) bearers of the service in a PTM mode₁) Transmitting RB to UE, using NP-PTM bearing to represent the sub PTM bearing, when K₁When the number of RBs is 0, each PTM bearer is split into unique sub PTM bearers, and the sub PTM bearers are used for transmitting all the RBs of the service to the UE in a PTM mode; and on the BWP where the PTM bearer is positioned, the MAC layer allocates wireless resources for each sub PTM bearer of the PTM bearer and sends each sub PTM bearer through the allocated resources.

In other optional embodiments, for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP on which the bearer is located, including: for each activated PTP bearer, determining the UE using the PTP bearer, and sending the configuration information of the PTP bearer, the configuration information of the corresponding PTM bearer and the configuration information of DL BWP configured for the UE to the UE using the PTP bearer through dedicated signaling; the corresponding PTM bearer is used for transmitting the service, is in an inactive state, and is positioned on the same MBS special BWP with the PTP bearer; and the MAC layer determines the BWP for transmitting the PTP bearer and transmits the PTP bearer on the corresponding BWP.

In another optional embodiment, for each RRC connected UE receiving the service, during transmission of the service, the MAC layer dynamically switches the transmission mode of the service between PTM and PTP, including: when the MAC layer determines that the service is transmitted through the PTP bearer of the UE, the PTP bearer is activated; when the MAC layer determines that one or more RBs of the service are transmitted through the PTP bearer of the UE, each RB which needs to be transmitted in a PTP mode in the PTP bearer of the UE is activated; for each activated RB, an RLC entity associated with the RB in a PTP bearer of the UE determines a subscript of a first PDCP PDU to be transmitted, extracts the PDCP PDU from the data storage area from the PDCP PDU, executes corresponding processing, and transmits the generated RLC PDU to a MAC layer through a corresponding DTCH; for the UE, if the transmission of each activated RB in the PTP bearer of the UE causes the parameter transmission change of the DRX mode configured to the UE by the MAC layer, the MAC layer sends an MAC CE in advance for transmitting a new DRX mode to the UE; after the new DRX mode takes effect, the MAC layer transmits each activated RB to the UE based on the new DRX mode; in the process of transmitting the service through the PTP bearer, when the MAC layer determines to suspend transmitting part or all RBs through the PTP bearer, the part or all RBs enter an inactive state from an active state, and the MAC layer informs RLC entities corresponding to the part or all RBs; each notified RLC entity inquires about INDEX stored in the corresponding data storage area and borne by the PTM in the storage area, and if the notified RLC entity finds that a plurality of PDCP PDUs before the PDCP PDU corresponding to the INDEX are not transmitted by the notified RLC entity, the notified RLC entity transmits the indication information of the slow speed to the MAC layer; then, the RLC entity continuously sends the PDCP PDU which is not transmitted to the MAC layer through the corresponding DTCH; after all the untransmitted PDCP PDUs are issued to the MAC layer, the RLC entity stops transmitting the RLC PDUs to the MAC layer through the DTCH; when no RLC entity is configured for the inactive PTM/PTP bearing, the state of the RLC entity becomes idle, and the connection of the RLC entity and the corresponding DTCH is disconnected; and after receiving the indication information of the RLC entity with low speed, the MAC layer promotes the scheduling priority of the RB in the PTP bearer and preferentially schedules the radio resource for the RB.

In another optional embodiment, for each RRC connected UE receiving the service, during transmission of the service, the MAC layer dynamically switches the transmission mode of the service between PTM and PTP, including: for the BWP, whenever the number of RRC connected UEs receiving the service on the BWP increases or the location of the existing UEs receiving the service changes, the MAC layer determines whether to activate the PTM bearer in an inactive state configured for the service by the BWP; when the MAC layer determines to activate the PTM bearing, if the RLC entity is not configured for the PTM bearing, the MAC layer triggers the RLC layer to configure the RLC entity for the PTM bearing; each RLC entity of the PTM load extracts the parameters INDEX saved in the data storage area by each activated PTP load from the corresponding data storage area, selects the PDCP PDU generated earliest from the PDCP PDUs indicated by each INDEX, and starts from the PDCP PDU and is saved in the data storage area by the RLC entityExtracting PDCP PDU for assembling RLC PDU, and transmitting the assembled RLC PDU to the MAC layer through SC-MTCH; the MAC layer receives the PTM to carry RLC PDUs transmitted through each SC-MTCH; the MAC layer sends the PTM bearer on the BWP; before transmitting the PTM bearer, the MAC layer transmits MAC CE to each UE which receives the service through PTP bearer on the BWP; in the process of transmitting the service through the PTM bearer, the MAC layer gradually stops transmitting the service to each UE through the PTP bearer; for the PTP bearer for stopping transmitting the service, the MAC layer triggers the PTP bearer to enter an inactive state; for each PTP bearer entering the inactive state, when no RLC entities are configured for the inactive PTM/PTP bearer, K RLC entities occupied by each PTP bearer stopping transmitting the service enter an idle state; in the process of transmitting the service through PTM bearer, the MAC layer determines whether to activate part or all RBs in PTP bearer of UE; for each activated RB in the PTP bearer, the MAC layer transmits the RB through the PTP bearer; in the process of transmitting the service through the PTM bearer, the MAC layer determines to send a beam set of the PTM bearer; when the number of beams included in the beam set for transmitting the PTM bearer is M₁When the value is 0, the MAC layer triggers the load to enter an inactive state; and when the RLC entities are not configured for the inactive bearer, the MAC layer also triggers K RLC entities occupied by the PTM bearer in the RLC layer to enter an idle state.

In other optional embodiments, the transmitting, in the target cell, the MBS to the UE through a corresponding bearer through signaling interaction between the source cell and the target cell in the process that the UE moves from the source cell to the target cell includes: the source cell executes a first process when determining to execute cell switching according to the received measurement report of the UE, and sends an RRC switching request message to a target cell; wherein the RRC handover request message comprises: the configuration information of the service currently received by the UE, the C-RNTI and SPS C-RNTI of the UE and the configuration information of the common service; the configuration information of the service currently being received by the UE includes: TMGI, conversation ID, G-RNTI and SPS G-RNTI of the said business, ID of MBS special BWP where PTP bearing of UE locates, basic configuration information of PTP bearing of UE and basic configuration information of PTM bearing of the said business on BWP where PTP bearing of UE locates; the first processing comprises that if the PTP bearer of the UE is not activated, the RRC layer sends a message for activating the PTP bearer of the UE to the MAC layer of the cell, and the MAC layer activates the PTP bearer of the UE according to the message and transmits the service through the bearer; after receiving the RRC switching request message, the target cell executes a second process and feeds back a switching request confirmation message to the source cell; and the source cell sends RRC reconfiguration information to the UE according to the received switching request confirmation information so as to enable the UE to establish a corresponding bearer according to the RRC reconfiguration information and receive the service through the established bearer in the target cell.

In other optional embodiments, when the target cell transmits the service through at least one active PTM bearer; the executing the second processing and feeding back the handover request acknowledgement message to the source cell includes: selecting one BWP from the BWPs in which each active PTM bearer is positioned, and configuring a PTP bearer for the UE on the selected BWP so as to perform PTM/PTP switching after the UE moves to the target cell; the target cell saves the TMGI, the session ID, the G-RNTI, the SPS G-RNTI, the C-RNTI and the SPS C-RNTI in the RRC switching request message; the target cell sends the handover request acknowledgement message to the source cell, wherein the handover request acknowledgement message includes: ID of MBS special BWP where PTP load of UE locates, PTM load activation indication, DRX mode of PTP load and DRX mode of PTM load and configuration information related to common service; the source cell sends an RRC reconfiguration message to the UE according to the received handover request acknowledgement message, so that the UE establishes a corresponding bearer according to the RRC reconfiguration message, and receives the service through the established bearer in the target cell, including: the source cell sends an RRC reconfiguration message to the UE according to the received switching request confirmation message, wherein the RRC reconfiguration message comprises: ID of MBS special BWP, PTP loading indication, PTM loading indication, configuration information of MBS special BWP, DRX mode of PTP loading, DRX mode of PTM loading and configuration information of common service; the UE refreshes the configuration information of the PTP/PTM bearer stored by the UE according to the DRX mode of the PTP/PTM bearer; when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; after the target cell is switched to, the UE receives the PTP bearer and the PTM bearer on the corresponding BWP according to the refreshed configuration information of the PTP/PTM bearer; and the UE continues to receive the common service after being switched to the target cell according to the configuration information related to the common service in the message.

In other optional embodiments, when the target cell does not configure an active PTM bearer for the service and transmits the service only through an active PTP bearer, the performing the second process and feeding back a handover request acknowledgement message to the source cell includes: the target cell determines the BWP in which each activated PTP bearer is located, selects a BWP from the BWPs, and if the ID of one BWP in the BWPs is the same as the ID of the BWP in the handover request, the target cell preferentially selects the BWP; the target cell configures PTP bearer for the UE on the selected BWP, so that the UE receives the service through the bearer after being switched to the target cell; if the UE has common service, configuring the common service of the UE on the MBS special BWP or a certain universal BWP of the BWP; the target cell stores TMGI, session ID, G-RNTI, SPS G-RNTI, C-RNTI and SPS C-RNTI in the switching request; the target cell sends a switching request confirmation message to the source cell, wherein the switching request confirmation message comprises: ID of MBS special BWP where PTP load of UE locates, DRX mode of PTP load and configuration information of common service; the source cell sends an RRC reconfiguration message to the UE according to the received handover request acknowledgement message, so that the UE establishes a corresponding bearer according to the RRC reconfiguration message, and receives the service through the established bearer in the target cell, including:

the source cell sends an RRC reconfiguration message to the UE according to the received switching request confirmation message, wherein the RRC reconfiguration message comprises: ID of MBS special BWP, receiving PTP loading indication, configuration information of MBS special BWP, DRX mode of PTP loading and configuration information of common service; the UE refreshes the configuration information of the PTP bearer stored by the UE according to the DRX mode of the PTP bearer in the switching request; when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; and deleting the DRX mode of the PTM bearer from the refreshed configuration information of the PTM bearer; after the target cell is switched to, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by the UE; and, prepare to receive PTM and bear the weight of in the target cell according to the configuration information that PTM that oneself refreshes bears the weight of; and the UE continues to receive the common service after being switched to the target cell according to the configuration information of the common service in the message.

In other optional embodiments, when the target cell does not transmit the service, the executing the second processing and feeding back a handover request acknowledgement message to the source cell includes: selecting a BWP from MBS special BWP, configuring activated PTP load for UE on the BWP, and configuring non-activated PTM load for the service; when the PTP bearer is configured for the UE, the basic configuration information of the PTP bearer in the switching request is used as the basic configuration information of the PTP bearer configured for the UE; when configuring PTM load bearing for the service, using the PTM load bearing basic configuration information in the switching request as the basic configuration information of the PTM load bearing; determining the configuration information of the BWP in the configuration information of the PTP/PTM bearer according to the configuration information of the selected BWP; if the UE has common service, configuring the common service of the UE on the MBS special BWP or a certain universal BWP of the BWP; the target cell stores TMGI, session ID, G-RNTI, SPS G-RNTI, C-RNTI and SPS C-RNTI in the switching request; the target cell determines the session of the MBS needing 5GC transmission according to the TMGI and the session ID of the MBS in the switching request, and triggers the 5GC to transmit the control plane information and the user plane data of the service to the target cell through a control plane interface and a user plane interface respectively by a control plane interface between the target cell and the 5 GC; the target cell sends a handover request acknowledgement message to the source cell, wherein the handover request acknowledgement message includes: ID of MBS special BWP where PTP load of UE locates, DRX mode of PTP load and configuration information of common service; the source cell sends an RRC reconfiguration message to the UE according to the received handover request acknowledgement message, so that the UE establishes a corresponding bearer according to the RRC reconfiguration message, and receives the service through the established bearer in the target cell, including: the source cell sends an RRC reconfiguration message to the UE according to the received switching request confirmation message, wherein the RRC reconfiguration message comprises: ID of MBS special BWP, receiving PTP loading indication, configuration information of MBS special BWP, DRX mode of PTP loading and configuration information of common service; the UE refreshes the configuration information of the PTP bearer stored by the UE according to the DRX mode of the PTP bearer in the message; when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; deleting the DRX mode of the PTM bearer in the refreshed configuration information of the PTM bearer; after the target cell is switched to, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by the UE; and the UE prepares to receive the PTM bearer in the target cell according to the configuration information of the self-refreshed PTM bearer; and the UE continues to receive the common service after being switched to the target cell according to the configuration information of the common service in the message.

In other optional embodiments, the transmitting, in the target cell, the MBS to the UE through a corresponding bearer through signaling interaction between the source cell and the target cell in the process that the UE moves from the source cell to the target cell includes: when a target cell receives a switching request sent by a source cell, for an MBS being received by UE, if the target cell transmits the service by PTM bearing and/or PTP bearing, for each RB of the MBS, only newly generated PDCP PDU is placed in a data storage region of the RB from the current moment; determining SN of PDCP PDU generated earliest in storage area of kth RB by TSN_kRepresents the SN; transmitting K SNs to a source cell through a handover request acknowledgement message, the K SNs being: TSN_kK is 1, … …, K; after receiving the switching request confirmation message, the source cell determines, for the UE in the switching process, a parameter INDEX stored in a storage area of a kth RLC entity in a PTP bearer of the UE in the kth RB; by SSN_kSN indicating PDCP PDU to be extracted next by the kth RLC entity; if SSN_kCorresponding PDCP PDU generation time is earlier than TSN_kCorresponding PDCP PDU shows that the transmission speed of the PDCP PDU of the kth RB in the PTP load of the UE in the source cell is later than that of the same RB in the target cell, and STSN is used_kDenotes SN as TSN_kThe source cell is SSN from SN in the storage area corresponding to the kth RB_kThe PDCP PDUs start to extract each PDCP PDU until the SN is extracted as STSN_kPDCP PDU of (1); forwarding the extracted PDCP PDUs to a target cell; if SSN_kCorresponding PDCP PDU generation time later than TSN_kWhen the UE is in the source cell, the transmission speed of the PDCP PDU of the kth RB in the PTP bearer of the UE in the source cell is higher than that of the same RB in the target cell, and the corresponding PDCP PDU is not required to be forwarded for lossless reception of the kth RB in the source cell; for the forwarded PDCP PDUs of the kth RB, in the target cell, the kth RLC entity in the PTP bearer of the UE preferentially transmits the forwarded PDCP PDUs to the MAC layer, so that the MAC layer preferentially transmits the forwarded PDCP PDUs; after the transmission of the forwarded PDCP PDU is finished, the RLC entity starts to transmit the PDCP PDU in the corresponding data storage area; or, when the target cell receives the handover request sent by the source cell, for the MBS being received by the UE, if the target cell does not transmit the service, the target cell carries the nondata in the handover request message, where the nondata is 0 and is used to indicate that the target cell has not transmitted the MBS; after receiving the switching request confirmation message, when the NoData in the message is 0, for the UE in the switching process, the source cell determines the parameter INDEX stored in the storage area of the k-th RB by the k-th RLC entity in the PTP bearer of the UE, and uses SSN_kSN indicating PDCP PDU to be extracted next by the kth RLC entity; for each RB in the PTP bearer of the UE, the source cell forwards PDCP PDUs stored in a data storage area of the RB to the target cell in sequence from the next PDCP PDU to be extracted, and when a new PDCP PDU is put into the storage area, all the newly put PDCP PDUs also need to be forwarded to the target cell in sequence; the target cell receives PDCP PDUs of all RBs forwarded by the source cell; after the target cell starts to receive the MBS conversation of the service from the 5GC, the target cell determines the SN of the first PDCP PDU of each RB in the received MBS conversation; will be SSN before N is denoted STOPSN; if the PDCP PDU received from the source cell and forwarded by the RB comprises the PDCP PDU with the SN of STOPSN, the target cell does not need the source cell to forward the PDCP PDU of the RB; otherwise, the target cell forwards the PDCP PDU of the RB to the source cell until the PDCP PDU with the SN of STOPSN is forwarded to the target cell; the target cell generates a STOP indication message according to the generated STOP indication message, wherein the STOP indication message carries a parameter STOP, and when the STOP is 1, the target cell indicates that the source cell STOPs forwarding the PDCP PDU; when the STOP is 0, carrying an RB list in the message, for instructing the source cell to forward only PDCP PDUs of each RB in the RB list; when receiving a STOP indication message from the target cell, if STOP in the message is 1, the source cell STOPs forwarding PDCP PDUs of each RB of the service; if STOP in the message is 0, the source cell extracts the carried K in the message₂For each group of parameters in the list, the source cell determines the RB which needs to continuously forward the PDCP PDU according to the RB subscript in the group of parameters; determining the SN of the last PDCP PDU which needs to be forwarded in the PDCP PDUs of the RB according to the STOPSN in the set of parameters; and for each RB to be forwarded, the source cell continues to forward the PDCP PDU from the storage area of the RB until the PDCP PDU with the SN of STOPSN is completely forwarded.

In other optional embodiments, the method further comprises: determining one base station from a plurality of interconnected base stations as a main node, and determining base stations except the main node as auxiliary nodes; wherein, the unified configuration and corresponding configuration result across the gNB executed by the master node includes: in a same-frequency networking scene, a main node uniformly configures at least one MBS special BWP for an NR cell transmitting MBS and at least one general BWP for each MBS special BWP, wherein the general BWP includes the MBS special BWP, each MBS special BWP is used for transmitting MBS to RRC connected state UE in a PTM/PTP mode, and for UE receiving MBS on one MBS special BWP, the general BWP of the MBS special BWP is used for bearing the common service of the UE; uniformly configuring a CORESET and a search space for each MBS special BWP, wherein the CORESET and the search space are used for bearing the scheduling information of the MBS, and uniformly configuring the CORESET and the search space for each general BWP of each MBS special BWP, and the CORESET and the search space are used for bearing the scheduling information of the common service; one MBS-specific BWP and the BWP's general BWP may share the same CORESET and search space; the master node generates configuration information of each MBS special BWP and configuration information of each general BWP of each MBS special BWP; for any MBS, the main node configures an SDAP entity for the service, is used for mapping the QOS flow contained in the MBS conversation of the service to the RB, configures a PDCP entity for each generated RB, and the PDCP entity of each RB generates a PDCP PDU for the RB; configuring G-RNTI and SPS G-RNTI for the service; the main node generates the following configuration information of the service: SDAP configuration information and PDCP configuration information; for any MBS, the main node determines the configuration information of K RLC entities carried by the PTM of the service, and the information is used for configuring the K RLC entities for any PTM of the service; k is the RB number of the service; for any MBS, the main node configures PDSCH parameters and PDCCH parameters for the service, and correspondingly determines PDSCH configuration information and PDCCH configuration information, wherein the PDSCH/PDCCH configuration information is used for the auxiliary node to configure the PDSCH parameters and the PDCCH parameters for the PTM bearer of the service; the primary node transmits the configuration information of each MBS special BWP, the configuration information of each general BWP of each MBS special BWP and the basic configuration information borne by the PTM of one MBS to the secondary node, wherein the basic configuration information borne by the PTM of one MBS comprises TMGI, session ID, G-RNTI, SPS G-RNTI, SDAP configuration information, PDCP configuration information, RLC configuration information, PDSCH configuration information and PDCCH configuration information.

In a second aspect, the present invention provides a transmission system for multicast broadcast service in an NR cell, including a plurality of interconnected base stations, where one base station is used as a master node and base stations other than the master node are used as slave nodes; wherein, the unified configuration and corresponding configuration result across the gNB executed by the master node includes:

in a same-frequency networking scene, a main node uniformly configures at least one MBS special BWP for an NR cell transmitting MBS and at least one general BWP for each MBS special BWP, wherein the general BWP includes the MBS special BWP, each MBS special BWP is used for transmitting MBS to RRC connected state UE in a PTM/PTP mode, and for UE receiving MBS on one MBS special BWP, the general BWP of the MBS special BWP is used for bearing the common service of the UE; uniformly configuring a CORESET and a search space for each MBS special BWP, wherein the CORESET and the search space are used for bearing the scheduling information of the MBS, and uniformly configuring the CORESET and the search space for each general BWP of each MBS special BWP, and the CORESET and the search space are used for bearing the scheduling information of the common service; one MBS-specific BWP and the BWP's general BWP may share the same CORESET and search space; the master node generates configuration information of each MBS special BWP and configuration information of each general BWP of each MBS special BWP;

for any MBS, the main node configures an SDAP entity for the service, is used for mapping the QOS flow contained in the MBS conversation of the service to the RB, configures a PDCP entity for each generated RB, and the PDCP entity of each RB generates a PDCP PDU for the RB; configuring G-RNTI and SPS G-RNTI for the service; the main node generates the following configuration information of the service: SDAP configuration information and PDCP configuration information;

for any MBS, the main node determines the configuration information of K RLC entities carried by the PTM of the service, and the information is used for configuring the K RLC entities for any PTM of the service; k is the RB number of the service;

for any MBS, the main node configures PDSCH parameters and PDCCH parameters for the service, and correspondingly determines PDSCH configuration information and PDCCH configuration information, wherein the PDSCH/PDCCH configuration information is used for the auxiliary node to configure the PDSCH parameters and the PDCCH parameters for the PTM bearer of the service;

the primary node transmits the configuration information of each MBS special BWP, the configuration information of each general BWP of each MBS special BWP and the basic configuration information of PTM bearing of one MBS to the secondary node, wherein the basic configuration information of the PTM bearing of one MBS comprises TMGI, session ID, G-RNTI, SPS G-RNTI, SDAP configuration information, PDCP configuration information, RLC configuration information, PDSCH configuration information and PDCCH configuration information;

the primary node and the secondary node are further configured to: configuring an activated PTM bearer and an inactivated PTM bearer for the service in each cell for transmitting the service, configuring an activated PTP bearer or an inactivated PTP bearer for each RRC connected-state UE for receiving the service, configuring an activated DL BWP for each RRC connected-state UE for receiving the service, determining configuration information of each PTM bearer, determining configuration information of each PTP bearer, and determining DL BWP configuration information of each UE; each active PTM/PTP bearer is used for transmitting the service, and each inactive PTM/PTP bearer is in a standby state before being activated and is not used for transmitting the service;

in each cell transmitting the service, a media access control MAC layer receives RLC PDUs of each radio link control protocol RLC entity loaded by each PTM/PTP configured for the MBS through a logic channel;

at each cell transmitting the traffic, for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP where the bearer is located;

for each RRC connected UE receiving the service, in the transmission process of the service, the MAC layer dynamically switches the transmission mode of the service between the PTM and the PTP;

in the transmission process of the service, for each RRC connected state UE receiving the service, in the process that the UE moves from a source cell to a target cell, the service is transmitted to the UE in the target cell through corresponding load bearing through signaling interaction between the source cell and the target cell.

The invention provides a transmission method and a system of multicast broadcast service in NR cells, which are characterized in that at least one MBS special bandwidth part BWP is uniformly configured in each cell for transmitting the multicast broadcast service MBS, and at least one general BWP is uniformly configured for each MBS special BWP, wherein, the MBS special BWP is used for transmitting the MBS to user equipment UE, the general BWP is used for bearing the common service of the UE, and the general BWP contains the MBS special BWP; for a broadcast multicast service, configuring a service data adaptation protocol SDAP entity for the service, wherein the SDAP entity is used for mapping each service quality QOS flow of the service MBS conversation to a radio bearer RB and configuring a packet data convergence protocol PDCP entity for each generated RB; configuring an activated PTM bearer and an inactivated PTM bearer for the service in each cell for transmitting the service, configuring an activated PTP bearer or an inactivated PTP bearer for each RRC connected-state UE for receiving the service, and configuring an activated DL BWP for each RRC connected-state UE for receiving the service; in each cell transmitting the service, a media access control MAC layer receives RLC PDUs of each radio link control protocol RLC entity loaded by each PTM/PTP configured for the MBS through a logic channel; at each cell transmitting the traffic, for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP where the bearer is located; for each RRC connected UE receiving the service, in the transmission process of the service, the MAC layer dynamically switches the transmission mode of the service between the PTM and the PTP; in the transmission process of the service, for each RRC connection state UE receiving the service, in the process that the UE moves from a source cell to a target cell, the service is transmitted to the UE through corresponding bearing in the target cell through signaling interaction between the source cell and the target cell, so that not only can the UE be ensured to continuously receive the MBS in PTM/PTP switching, but also the UE can be ensured to continuously receive the MBS through corresponding bearing in the target cell when the UE is switched from the source cell to the target cell.

Drawings

FIG. 1 is a diagram illustrating an MBS architecture in an NR system;

fig. 2 is a first flowchart illustrating a method for transmitting a multicast broadcast service in an NR cell according to the present invention;

fig. 3 is a flowchart illustrating a second method for transmitting a multicast broadcast service in an NR cell according to the present invention;

fig. 4 is a third flowchart illustrating a transmission method of a multicast broadcast service in an NR cell according to the present invention;

fig. 5 is a fourth flowchart illustrating a transmission method of a multicast broadcast service in an NR cell according to the present invention;

fig. 6 is a fifth flowchart illustrating a method for transmitting a multicast broadcast service in an NR cell according to the present invention;

fig. 7 is a sixth flowchart illustrating a method for transmitting a multicast broadcast service in an NR cell according to the present invention;

fig. 8 is a seventh flowchart illustrating a method for transmitting a multicast broadcast service in an NR cell according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the examples of the present invention will be clearly and completely described below with reference to the accompanying drawings in the examples of the present invention.

With the continuous development of wireless communication technology, New Radio Access (NR) systems have come into people's lives. In order to provide Multicast and Broadcast Service (MBS) in NR cell, Release 17Work Item (Release 17Work Item, abbreviated R17 WI) was set up in Radio Access Network (RAN) of 3rd Generation Partnership Project (3 GPP) in year 2019, 12 months: the NR MBS project.

Fig. 1 is a schematic diagram of an MBS architecture in an NR system, and as shown in fig. 1, the MBS architecture in the NR system includes an MBS server, a 5G Core network (5G Core network, abbreviated as 5GC), a Next Generation radio access network (Next Generation RAN, abbreviated as NG-RAN), and a User Equipment (User Equipment, abbreviated as UE).

Wherein, the MBS server provides broadcast/multicast service. For each broadcast/multicast service, the MBS server transmits user plane data and control plane information of the service to the 5GC through a user plane interface and a control plane interface between the 5GC and the MBS server, respectively.

The 5GC provides a user plane data transmission path and a control plane information transmission path for the broadcast/multicast service from the MBS server, and transmits the user plane data and the control plane information of the broadcast/multicast service to NG-RAN (gNB) through the two paths respectively.

The gNB determines an NR cell for transmitting the broadcast/multicast service according To control plane information of the broadcast/multicast service from the 5GC core network, and transmits the broadcast/multicast service in a Point-To-Multipoint (PTM) mode and/or a Point-To-Point (PTP) mode in the corresponding NR cell.

In the PTM mode, the gNB transmits the user plane data of the broadcast/multicast service to a group of UEs in the NR cell via a shared resource, and each UE receives the data of the broadcast/multicast service on the shared resource.

In the PTP mode, the gNB transmits the user plane data of the broadcast/multicast service to a specific UE in the NR cell via a dedicated resource, and the UE receives the data of the broadcast/multicast service on the dedicated resource.

As shown in fig. 1, the gNB establishes two PTM bearers and 1 PTP bearer for transmitting a broadcast/multicast service in an NR cell, and transmits the service to two groups of UEs in a PTM manner through the two PTM bearers and transmits the service to a specific UE through the 1 PTP bearer.

For an MBS, when the number of UEs receiving the service in the NR cell is small, such as: the number of the UE receiving the service is less than the number of beams adopted when a Synchronization Signal/Physical Broadcast Channel Block (SS/PBCH BLOCK, short for SS/PBCH BLOCK) in the current NR cell is sent, and the service is transmitted in a PTP mode, so that the service receiving performance of the UE can be improved, and wireless resources can be effectively saved; when the number of the UE receiving the service in the NR cell is large, the service is transmitted by the PTM mode, so that the radio resource can be effectively saved.

When the PTM method is used to transmit the MBS, if a BLock Error Rate (BLER) of MBS data received by a certain UE through the PTM bearer is high, a special PTP bearer may be established for the UE, and the MBS is transmitted to the UE in the PTP method, so as to improve the performance of receiving the MBS by the UE.

In summary, in an MBS transmission process, for a specific UE, the gNB may dynamically switch the transmission mode of the service between the PTM and the PTP or simultaneously transmit the service through the PTM and the PTP according to a change of a situation, and accordingly, the UE needs to dynamically switch the mode of receiving the service between the PTM and the PTP or simultaneously receive the same service through the PTM and the PTP.

In the NR MBS, it is explicitly required that, in the transmission process of the MBS, for a given Radio Resource Control (RRC) connected UE, under the condition of ensuring the continuity of the MBS service, the transmission mode of the broadcast/multicast service is dynamically switched between PTM and PTP, and meanwhile, the continuous reception of the MBS during the UE moving process needs to be ensured. However, there is currently no corresponding method to ensure the above requirements.

In order to solve the above problems, the present invention provides a transmission method of multicast broadcast service in NR cell, which can ensure that RRC connected UE continuously receives MBS during PTM/PTP handover, and can also ensure that UE continuously receives MBS during moving.

Fig. 2 is a first flowchart illustrating a method for transmitting a multicast broadcast service in an NR cell according to the present invention.

As shown in fig. 2, the method for transmitting multicast broadcast service in NR cell according to the present invention includes:

s101: in a same-frequency networking scene, in each cell for transmitting MBS, at least one MBS special Bandwidth Part (BWP for short) is uniformly configured, and each MBS special BWP is used for transmitting MBS to RRC connection state UE in a PTM/PTP mode. At least one general BWP is configured for each MBS special BWP in a unified way, each general BWP contains the MBS special BWP, and for RRC connected UE receiving MBS on one MBS special BWP, the general BWP of the BWP is used for bearing common service of the UE.

Specifically, in a same-frequency networking scenario, each gNB transmits uplink services and downlink services in each cell by using the same carrier frequency.

In the same-frequency networking scene, when the MBS is transmitted across gNB, a plurality of MBS special BWPs are uniformly configured in each cell controlled by gNB and used for transmitting the MBS to RRC connection state UE in a PTM/PTP mode. A Control Resource Set (referred to as "CORESET") and a search space are uniformly configured on each MBS dedicated BWP for bearing scheduling information of a Physical Downlink Shared channel (referred to as "PDSCH") used for transmitting MBS to RRC connected UE. If there are free resources on an MBS dedicated BWP, the resources may also be borrowed.

And uniformly configuring a plurality of universal BWPs for each MBS special BWP, wherein each universal BWP contains the MBS special BWP. And a CORESET and a search space are uniformly configured on each general BWP and are used for bearing PDSCH scheduling information, and the PDSCH is used for bearing common services and MBS transmitted in a PTP mode. A resource may also be borrowed if there is a free resource on a general BWP.

One MBS-specific BWP and one general BWP of the BWP may share the same CORESET and search space or have different CORESET and search spaces.

For the UE receiving MBS on MBS dedicated BWP, the normal service of the UE can be transmitted on a general BWP, and when the idle resources on MBS dedicated BWP are very small, the PTP bearer for transmitting MBS to the UE can be migrated to general BWP.

To configure MBS dedicated BWP and generic BWP uniformly across the gNB, it can be specified in the 3GPP NR protocol: in the same-frequency networking scene, each gNB adopts the same method to configure MBS special BWP and general BWP for the same downlink carrier frequency. Under the convention, although each gNB configures the MBS dedicated BWP and the general BWP on one downlink carrier frequency, the configuration result of each gNB is the same.

S102: for a broadcast/multicast Service, configuring a Service Data Attachment Protocol (SDAP) entity for the Service, and mapping each Quality of Service (QOS) flow included in an MBS session of the Service to a Radio Bearer (RB); configuring a Packet Data Convergence Protocol (PDCP) entity for each generated RB, wherein the PDCP entity is used for executing PDCP layer processing on an SDAP Protocol Data Unit (PDU) on the RB according to the requirement; uniformly configuring a Group Radio Network Temporary Identity (G-RNTI)/Semi-persistent Scheduling (SPS) G-RNTI for the service, wherein the Group Radio Network Temporary Identity is used for transmitting the service in a dynamic Scheduling mode/Semi-persistent Scheduling mode in each cell for transmitting the service; and uniformly configuring a C-RNTI/SPS C-RNTI for each RRC connection state UE receiving the service, wherein the C-RNTI is the short for Cell RNTI and is used for transmitting the service to the UE in a dynamic scheduling mode/semi-static scheduling mode in a Cell where the UE is located. The number of generated RBs is denoted by K.

In the invention, each cell transmitting the service in the cell controlled by the gNB shares the SDAP entity and each PDCP entity. The PDCP layer processing performed by the PDCP entity of each RB includes: generating a Sequence Number (SN), header compression and encryption. Whether header compression and encryption are employed depends on the need.

When the service is transmitted across gNBs, each gNB transmitting the service configures one SDAP entity for the service, and configures one PDCP entity for each RB generated by the SDAP entity. Preferably, the following is specified in the 3GPP NR protocol:

different gNBs perform the same processing for the SDAP entities configured for the service so that each gNB gets a set of the same RBs;

for each RB, different gnbs perform the same processing for the PDCP entity configured for that RB, so that the same PDCP PDU is generated for the PDCP entities configured for the same RB in different gnbs.

When the service is transmitted across gNBs, the same processing mode is adopted to enable each gNB to allocate the same G-RNTI/SPS G-RNTI for the service, and allocate the same C-RNIT/SPS C-RNTI for each RRC connection state UE receiving the service. And uniformly allocating a G-RNTI/SPS G-RNTI to the service, and uniformly allocating a C-RNTI/SPS C-RNTI to each RRC connection state UE receiving the service, so that the UE receiving the service can keep continuous receiving of the service when moving among cells across the gNB, and the content of configuration information is simplified to save radio resources.

In order to support UE to continuously receive an MBS in the movement of crossing gNB, before the core network transmits the MBS session of the service to each gNB, a time stamp or an initial frame number is periodically added in the MBS session of the service, so that each cell of crossing gNB sets the same SN for the same PDCP SDU on the same RB in the same MBS session.

S103: configuring an activated PTM bearer and an inactivated PTM bearer for the service in each cell for transmitting the service, configuring an activated PTP bearer or an inactivated PTP bearer for each RRC connection state UE for receiving the service, configuring activated DL BWP for each RRC connection state UE for receiving the service, determining configuration information of each PTM bearer, determining configuration information of each PTP bearer, and determining DL BWP configuration information of each UE. Each active PTM/PTP bearer is transmitting the service, and each inactive PTM/PTP bearer is in a standby state before being activated and is not used for transmitting the service.

Specifically, in each cell transmitting the service, a plurality of active PTM bearers and a plurality of inactive PTM bearers are configured for the service according to specific situations. Each PTM bearer is located on one MBS-specific BWP and different PTM bearers are located on different BWPs. And configuring a unique PTP bearer for each RRC connected UE receiving the service, wherein the PTP bearer is used for transmitting the service to the UE in a PTP mode. For each PTM bearer, the PTP bearer of the RRC connected UE receiving the bearer is located in the same BWP as the bearer.

Each active PTM/PTP bearer is transmitting the service, and each inactive PTM/PTP bearer is in a standby state before being activated and is not used for transmitting the service.

Configuring a PTM/PTP bearer in a cell specifically includes: and configuring K RLC entities and K SC-MTCH/DTCH for the bearer, wherein the kth RLC entity is connected with the PDCP entity of the kth RB of the service upwards and is connected with the kth SC-MTCH/DTCH downwards.

Optionally, configuring an inactive PTM/PTP bearer in the cell specifically includes: no RLC entity is configured for the bearer, only K groups of RLC parameters and K SC-MTCH/DTCH are configured for the bearer, the kth group of RLC parameters are used for configuring the kth RLC entity of the bearer, and the kth SC-MTCH/DTCH corresponds to the PDCP entity of the kth RB.

After the above process is completed, configuring an activated DL BWP for each RRC connected UE receiving the service.

Finally, determining the configuration information of each PTM bearer, determining the configuration information of each PTP bearer, and determining the DL BWP configuration information of each UE.

The DL BWP configuration information of each UE at least includes:

(1) configuration information of activated DL BWP configured for UE

(2) General service related configuration information (if the UE has general service)

(3) Other DL BWP configuration information (if other BWPs are configured for the UE)

S104, in each cell for transmitting the service, the MAC layer receives the RLC PDU of each RLC entity borne by each PTM/PTP through a logic channel.

Specifically, for each active PTM bearer, the MAC layer receives RLC PDUs of K RBs of the service through K SC-MTCHs configured for the bearer. For each activated PTP bearer, the MAC layer receives RLC PDUs of K RBs of the service through K DTCHs configured for the bearer. When only a part of RBs in an activated PTP bearer are activated, the MAC layer receives RLC PDUs of each activated RB through each DTCH corresponding to the RBs.

For each inactive PTM/PTP bearer, the bearer is connected with the MAC layer through K SC-MTCH/DTCH, but no RLC PDU exists on the K SC-MTCH/DTCH.

For the RRC connection state UE receiving the service, the DTCH used for bearing the common service of the UE and the DTCH used for bearing the MBS are numbered uniformly or respectively. When DTCHs of common services and DTCHs carrying MBS are multiplexed together at an MAC layer for transmission, the DTCHs multiplexed together need to be numbered uniformly; when DTCH of common service and DTCH carrying MBS are transmitted in time division multiplexing mode in MAC layer, they can be numbered separately.

Currently, there are a maximum of 32 DTCHs for a UE in the 3GPP NR protocol. In the case of transmitting the MBS by PTP bearer, if 32 DTCHs are not enough, the number of DTCHs can be increased. Specifically, at present, 6 bits are used in the MAC PDU to indicate the index of the logical channel, the number of bits indicating the index of the logical channel may be increased, for example, 7 or 8 bits are used to indicate the index of the logical channel, and accordingly, the newly added index value of the logical channel may be used to assign the index to the DTCH, so as to support more DTCHs.

S105, in each cell transmitting the service, for each activated PTM/PTP bearer, the MAC layer sends the bearer on the BWP where the bearer is located.

S106, for each RRC connection state UE receiving the service, in the transmission process of the service, the MAC layer dynamically switches the transmission mode of the service between the PTM and the PTP.

S107, in the process of transmitting the service, for each RRC connected state UE receiving the service, in the process that the UE moves from the source cell to the target cell, the service is transmitted to the UE in the target cell through corresponding bearing through signaling interaction between the source cell and the target cell.

In summary, the method for maintaining the continuity of the MBS service in the NR cell provided by the present invention employs the following processing, which not only can ensure that the UE continuously receives the MBS in the PTM/PTP handover, but also can ensure that the UE continuously receives the MBS through the corresponding bearer in the target cell when the UE is handed over from the source cell to the target cell.

(1) In each cell transmitting multicast broadcast service MBS, uniformly configuring at least one MBS special bandwidth part BWP and uniformly configuring at least one general BWP for each MBS special BWP, wherein the MBS special BWP is used for transmitting MBS to UE, the general BWP is used for carrying common service of the UE, and the general BWP includes the MBS special BWP;

(2) configuring a service data adaptation SDAP entity for MBS, wherein the SDAP entity is used for mapping each service quality QOS flow of MBS conversation to RB and configuring a packet data convergence PDCP entity for each generated RB;

(3) selecting a plurality of BWPs from MBS special BWPs for transmitting the MBS, configuring point-to-multipoint PTM (packet transfer protocol) bearing and point-to-point PTP (Point-to-Point PTP) bearing for the MBS on each selected MBS special BWP, and configuring activated DL BWP for receiving RRC connected UEP (unified equipment protocol) of the MBS;

(4) the media access control MAC layer receives RLC PDU of each RLC entity of each PTM/PTP load-bearing configured for the MBS through a logic channel;

(5) the MAC layer transmits the PTM/PTP load on the BWP where the activated PTM/PTP load is positioned;

(6) for each RRC connection state UE receiving the MBS, the MAC layer dynamically switches the transmission mode of the MBS between PTM/PTP in the MBS transmission process;

and in the process that the UE moves from the source cell to the target cell, transmitting the MBS to the UE in the target cell through a corresponding bearer through signaling interaction between the source cell and the target cell.

Fig. 3 is a second flowchart of a method for transmitting a multicast broadcast service in an NR cell according to the present invention, where on the basis of the method for transmitting a multicast broadcast service in an NR cell according to the present invention shown in fig. 2, a specific implementation method of S103 is shown in fig. 3, and specifically includes the following steps:

s1031: in each cell transmitting the service, configuring N for the service according to the number of RRC connected state UE receiving the service and other related information₁An active PTM bearer, N in different cells₁May be different.

Specifically determining N₁The method is not the content of the invention and is not described in detail.

S1032: when N is present₁>0, when configuring each activated PTM bearer, selecting a BWP from the uniformly configured MBS special BWPs for sending the PTM bearer. Different BWPs are selected for different PTM bearers. And configuring K RLC entities and K SC-MTCHs for the PTM bearer, wherein the K RLC entity is connected with the PDCP entity of the K RB of the service upwards and is connected with the K SC-MTCH downwards. And configuring PTP bearers for RRC connected-state UEs receiving the PTM bearer on the selected BWP, wherein the PTP bearer of each UE is transmitted on the BWP. And configuring K RLC entities and K DTCHs for the PTP bearer of each UE, wherein the kth RLC entity is connected with the PDCP entity of the kth RB of the service upwards and is connected with the kth DTCH downwards. The PTP bearer configured for each UE is in an inactive state.

The PTP bearer configured to the UE according to the above method is not really used for transmitting the service, but a transmission path from the SDAP layer to the MAC layer is established for the bearer, the path does not start transmitting the service, and the bearer is in an inactive state. And activating the PTP bearer of the UE when necessary so as to transmit the service to the UE in a PTP mode through the bearer.

S1033: when N is present₁When 0, one or more BWPs (one BWP is adopted as much as possible) are selected for reception in the MBS-specific BWPs with unified configurationAnd the RRC connected UE of the service configures PTP load. The PTP bearer configured on a selected BWP is transmitted on that BWP. Each selected BWP is recorded. And configuring K RLC entities and K DTCHs for the PTP bearer of each UE, wherein the kth RLC entity is connected with the PDCP entity of the kth RB of the service upwards and is connected with the kth DTCH downwards. And the PTP bearer configured for each UE is in an activated state and is used for transmitting the service to the UE.

S1034: in N₁>At time 0, if there is at least one RRC connected UE receiving the service, and the UE cannot receive the service through any active PTM bearer, excluding BWPs used for transmitting the active PTM bearer in the MBS dedicated BWPs configured in a unified manner, and selecting one or more BWPs (using only one BWP as far as possible) in the remaining BWPs for configuring PTP bearers for the UE. And the PTP bearer configured on the selected BWP is transmitted on the BWP. Each selected BWP is recorded. And configuring K RLC entities and K DTCHs for the PTP bearer of each UE, wherein the kth RLC entity is upwards connected with the PDCP entity of the kth RB of the service and is downwards connected with the kth DTCH. And the PTP bearer configured for the UE is in an activated state and is used for transmitting the service to the UE.

S1035: after the above-described processing is performed, the number N of BWPs when recorded₃And if not, configuring a PTM bearer for the service on each recorded BWP, configuring K RLC entities and K SC-MTCHs for the PTM bearer, wherein the K RLC entity is connected with the PDCP entity of the K RB of the service upwards and is connected with the K SC-MTCH downwards. Each configured PTM bearer is in an inactive state.

The PTM bearer configured in the above manner is not actually used for transmitting the service, but a transmission path from the SDAP layer to the MAC layer is established for the bearer, and the path does not start to transmit the service and is in an inactive state. And activating the PTM bearer when necessary so as to transmit the service to the UE in a PTM mode through the bearer.

S1036: after configuring the PTM bearer and the PTP bearer for the service, configuring activated DL BWP for each RRC connected UE receiving the service through the PTM bearer or the PTP bearer.

Specifically, determining MBS-dedicated BWP in which PTM/PTP bearer adopted by the UE when receiving the service is located, and configuring the MBS-dedicated BWP as active DL BWP of the UE. Under the configuration method, the active DL BWP of the UE is the MBS BWP where the UE receives the service.

Optionally, determining MBS-dedicated BWPs in which a PTM/PTP bearer adopted by the UE when receiving the service is located, selecting one general BWP from the general BWPs of the MBS-dedicated BWPs, and configuring the general BWP as an activated DL BWP of the UE. Under the configuration method, the activated DL BWP of the UE includes the MBS BWP that the UE receives the service.

When the UE has normal traffic to receive, the normal traffic of the UE may be configured on the active DL BWP of the UE.

S1037: after the above processes are completed, configuration information of each PTM bearer, configuration information of each PTP bearer, and DL BWP configuration information of each UE are determined.

In the method of the present invention, the configuration information of each PTM/PTP bearer includes: basic configuration information and BWP configuration information.

Specifically, the basic configuration information of a PTM bearer includes the following:

(1) TMGI, conversation ID, G-RNTI and SPS G-RNTI of the service;

(2) configuration information of the SDAP entity of the service;

(3) configuration information of K PDCP entities of the service;

(4) configuration information of K RLC entities carried by the PTM;

(5) physical layer configuration information: configuration information of PDSCH, configuration information of PDCCH.

Specifically, the BWP configuration information of one PTM bearer includes the following:

(1) transmitting basic parameters of BWP of the PTM bearer;

(2) sending configuration information of CORESET and search space on BWP carried by the PTM;

(3) DRX mode of the PTM bearer: and the UE monitors the scheduling information of the PTM bearer according to the DRX mode so as to receive the service. Inactive PTM bearers do not have DRX mode.

In the method of the present invention, each PTM bearer transmitting the service in the same cell has the same basic configuration information and different BWP configuration information, that is: in the same cell, each PTM bearer for transmitting the service transmits the service on different BWPs by adopting the same parameters.

In the method of the present invention, for the service, the PTM bearers configured for the service on the same MBS-dedicated BWP in different cells have the same basic configuration information, except for DRX mode. When the UE moves in different cells, if the source cell and the target cell use the same MBS dedicated BWP to transmit the service in PTM bearer, the UE may directly use the configuration information of the PTM bearer of the source cell to receive the service in the same BWP in the target cell.

Specifically, the basic configuration information of the PTP bearer of the UE includes the following:

(1) TMGI, session ID of the service;

(2) C-RNTI and SPS C-RNTI of the UE;

(3) configuration information of the SDAP entity of the service;

(4) configuration information of K PDCP entities of the service;

(5) configuration information of K RLC entities carried by PTP;

(6) physical layer configuration information: configuration information of PDSCH, configuration information of PDCCH.

Specifically, the BWP configuration information of the PTP bearer of the UE includes the following:

(1) transmitting basic parameters of BWP of the PTP bearer;

(2) sending configuration information of CORESET and search space on BWP carried by PTP;

(3) DRX mode of the PTP bearer: and the UE monitors the scheduling information of the PTP bearer according to the DRX mode so as to receive the service. Inactive PTP bearers do not have DRX mode.

The PTP bearer of the UE in the cell receiving the service and the PTM bearer transmitting the service on the same MBS-dedicated BWP have the following same information.

(1) TMGI, session ID of the service;

(2) configuration information of the SDAP entity of the service;

(3) configuration information of K PDCP entities of the service;

(4) physical layer configuration information: configuration information of PDSCH, configuration information of PDCCH;

(5) sending basic parameters of BWP of the bearer;

(6) and sending the configuration information of CORESET and search space on the loaded BWP.

When the kth RLC entity of a PTP bearer and the kth RLC entity of a PTM bearer on the same BWP use the same RLC mode (TM mode or UM mode), the two RLC entities have the same RLC parameters, but the logical channels connected to the two RLC entities are DTCH and SC-MTCH, respectively.

In the method of the present invention, the following information of PTP bearers adopted by the UE receiving the service in different cells is necessarily the same:

(1) TMGI, session ID of the service;

(2) C-RNTI and SPS C-RNTI of the UE;

(3) configuration information of the SDAP entity of the service;

(4) configuration information of K PDCP entities of the service;

(5) configuration information of K RLC entities;

In the method of the present invention, the PTP bearers employed by the UE receiving the service on the same MBS-dedicated BWP in different cells have the same basic configuration information, and the same BWP configuration information except for the DRX mode. Therefore, when the UE moves in different cells, if the source cell and the target cell use the same BWP to transmit the service in PTP bearer, the UE may directly use the configuration information of the PTP bearer of the source cell to receive the service in the same BWP in the target cell.

The PDSCH configuration information includes: parameters used for PDSCH, PDSCH DMRS, PDSCH PTRS, etc.

The PDCCH configuration information includes: parameters used for PDCCH and parameters used for PDCCH DMRS, etc.

In the above steps S1032 to S1035, when configuring the RLC entity for each PTM/PTP bearer, the transmission mode adopted by the RLC entity needs to be determined.

Specifically, the RLC entity configured for the PTM bearer may employ the TM mode or the UM mode. The RLC entity configured for the PTP bearer may employ TM mode, UM mode or AM mode.

When a RB carries voice service, the RLC entity associated with the RB adopts a TM mode, the PDCP entity of the RB strips the VOIP head of the input PDCP SDU, and the output PDCP PDU only consists of voice payload.

In the above steps S1032 to S1035, in order to save the resources of the gNB, for each RB of the service, the RLC entity associated with the RB shares a data storage area, where the data storage area is used to store the PDCP PDUs from the PDCP entity of the RB and the necessary parameters adopted by the respective RLC entities associated with the RB. Each RLC entity independently extracts PDCP PDUs from the memory area to assemble RLC PDUs, and inquires necessary parameters employed by other RLC entities stored in the memory area, if necessary, to perform corresponding processing.

Specifically, for each RB of the service, one RLC entity is associated with each RB in each PTM/PTP bearer, and N is total₁+N₂+N₃One RLC entity is associated with the RB. For each RB of the service, let N associated with that RB₁+N₂+ N3 RLC entities share a data storage area for storing PDCP PDUs from the PDCP entity of the RB and the necessary parameters to be employed by each RLC entity associated with the RB. The shared data storage area not only can greatly save the storage space of the gNB, but also facilitates the coordination process between RLC entities associated with the same RB, such as: one RLC entity can know the transmission progress of the PDCP PDU of the same RB by other RLC entities through necessary parameters of other RLC entities stored in a shared data storage area, thereby ensuring continuous transmission of the service in the PTM/PTP switching.

In the above steps S1032 to S1035, in order to further save the resources of the gNB, it is not necessary to configure K RLC entities for each inactive PTM/PTP bearer, but it is only necessary to configure K sets of RLC parameters and K SC-MTCH/DTCHs for each inactive PTM/PTP bearer, where the kth set of RLC parameters is used to configure the kth RLC entity of the bearer, and the kth SC-MTCH/DTCH corresponds to the kth PDCP entity of the RB.

When the RLC entity is not configured for the inactive PTM/PTP bearer, each inactive PTM/PTP bearer is disconnected in the RLC layer, that is: each inactive PTM/PTP carries one SDAP entity, K PDCP entities and K SC-MTCH/DTCH, but there is no K RLC entity connecting the K PDCP entity and the K SC-MTCH/DTCH. Since the bearer is in an inactive state and is not used for transmitting the traffic, there is no problem in disconnecting the bearer at the RLC layer. When the bearer is activated, K RLC entities can be immediately configured for the bearer through K sets of RLC parameters, and the kth RLC entity immediately connects the kth PDCP entity with the kth SC-MTH/DTCH, so that the bearer can transmit the service.

With N₄The invention discloses a method for indicating the number of PTM bearing in an inactive state and PTP bearing in an inactive state, when not configuring RLC entities for PTM/PTP bearing in an inactive state, in order to configure K RLC entities for the bearing immediately when PTM/PTP bearing is activated, the invention provides that: configuring N for the service₅<N₄And the k RLC entity in each group of RLC entities is connected with the PDCP entity of the k RB. Slave N when a PTM/PTP bearer is activated₅And selecting a group of idle RLC entities from the group of RLC entities, and configuring the group of RLC entities to the bearer. Specifically, the kth RLC entity is configured by using the kth set of RLC parameters configured for the bearer, and the RLC entity is connected to the kth SC-MTCH/DTCH of the bearer, so that the bearer can transmit the service.

When no RLC entity is configured for the PTM/PTP bearing in the inactive state, the invention provides that: allocating an RLC entity resource pool to the service, wherein the resource pool consists of a plurality of RLC entities, N₄R in the resource pool is shared by the inactivated bearingAn LC entity.

When the kth RB in the PTP bearer of the UE is activated, selecting an idle RLC entity from a resource pool, configuring the RLC entity by using the kth group RLC parameters of the PTP bearer of the UE, connecting the RLC entity with the PDCP entity of the kth RB of the service, and connecting the RLC entity with the kth DTCH in the PTP bearer of the UE.

When an inactive PTM bearer is activated, K idle RLC entities are selected from a resource pool for the bearer, a kth RLC entity is configured by using the kth group of RLC parameters of the PTM bearer, the RLC entity is connected with a PDCP entity of the kth RB of the service, and the RLC entity is connected with the kth SC-MTCH of the bearer.

Specifically, since each RB of the MBS generally has different QOS requirements, when the UE receives the MBS through the PTM bearer, the following occurs: the receiving quality of some RBs meets the QOS requirement, the receiving quality of some RBs does not meet the QOS requirement, the RBs which do not meet the QOS requirement need to be transmitted through PTP bearer, and all RBs do not need to be transmitted through PTP bearer. Thus, the RLC entity resource pool, N, may be set₄The PTM bearer in the inactive state and the PTP bearer in the inactive state share the RLC entity in the resource pool. When the receiving quality of the kth RB by one UE is not good, the kth RB in the PTP bearer of the UE can be activated, an idle RLC entity is selected from a resource pool, the RLC entity is configured by using the kth group of RLC parameters of the PTP bearer of the UE, the RLC entity is connected with the PDCP entity of the kth RB of the service, and the RLC entity is connected with the kth DTCH in the PTP bearer of the UE. Thus, the kth RB of the service can be transmitted through the PTP bearer.

For inactive PTM bearers, no separate activation of the RB or RBs of the bearer is used. Therefore, when the bearer is activated, K idle RLC entities are selected from a resource pool for the bearer, a kth RLC entity is configured with the kth set of RLC parameters of the PTM bearer, the RLC entity is connected to the PDCP entity of the kth RB of the service, and the RLC entity is connected to the kth SC-MTCH of the bearer. In this way, the bearer can transport the traffic.

In summary, for an MBS, after an activated PTM bearer is configured for the MBS on a MBS dedicated BWP, an inactive PTP bearer needs to be configured for each RRC connected UE receiving the PTM bearer on the BWP, and the PTP bearer of the UE is activated as necessary to transmit the service to the UE in a PTP manner, so as to improve the quality of receiving the service by the UE; after configuring the activated PTP bearer for the RRC connected UE receiving the MBS on a MBS dedicated BWP, it is further required to configure an inactive PTM bearer for the MBS on the BWP, activate the PTM bearer if necessary, for transmitting the service to the UE receiving the service on the BWP in a PTM manner, and after transmitting the MBS through the PTM bearer, successively deactivate each activated PTP bearer on the BWP for transmitting the service. When no RLC entities are configured for PTM/PTP bearing in the inactive state, after one PTP/PTM bearing is deactivated, the bearing releases occupied K RLC entities.

The method for configuring the PTM bearer and the PTP bearer can simplify the flow of dynamically switching the MBS transmission mode in the MBS transmission process.

Fig. 4 is a third schematic flow chart of a method for transmitting a multicast broadcast service in an NR cell according to the present invention, and based on the method for transmitting a multicast broadcast service in an NR cell according to the present invention shown in fig. 2 and fig. 3, in S105, when there is at least one active PTM bearer in a cell in which the service is transmitted, for each active PTM bearer, a specific method for a MAC layer to transmit the bearer on a BWP in which the bearer is located is shown in fig. 4, and specifically includes the following processes:

s1051: in each cell transmitting the service, for each active PTM bearer, for each RRC connected UE receiving the bearer, transmitting configuration information of the PTM bearer, configuration information of PTP bearers configured for the UE, and configuration information of DL BWP configured for the UE to the UE through dedicated signaling.

Since the contents of some items in the configuration information of the two bearers are the same, preferably, the configuration information of the PTP bearer transmitted to the UE only includes items with different contents.

The dedicated signaling may be: RRC reconfiguration message.

S1052: determining a SET of beams SET for transmitting the PTM bearer.

In each cell, the SS/PBCH BLOCK is transmitted over multiple beams that cover exactly the entire cell. In the present invention, M denotes the number of beams transmitting SS/PBCH BLOCK, and M denotes the mth beam, where M is 1, …, M.

For each PTM bearer, a beam is determined in which each UE receiving the bearer is located. When a UE is located on beam m, it indicates that the UE is within the coverage area of beam m. When a UE is located in the middle of two adjacent beams, that is, the UE is located at the edge of the coverage areas of the two beams at the same time, if there is no other UE in one of the two beams, the UE may be considered to be located in the beam of the two beams without other UE; if there is no other UE in both beams, the UE may be considered to be located in one of the beams; otherwise, the UE may be considered to be located within both beams.

For each beam, when at least one UE is located in the beam, the index of the beam is recorded. The PTM bearer is transmitted within the coverage area of each recorded beam. When there is only one UE in a recorded beam, a dedicated beam for the UE is used when transmitting the PTM bearer in the beam coverage area. A dedicated beam for a UE is generated by the gNB based on information about the UE, the beam being directed to the UE. When there is more than one UE in a recorded beam, the beam is used when transmitting the PTM bearer in the beam coverage area. However, if the UEs in the beam are concentrated within a narrow direction within the coverage area of the beam, a narrow beam may be synthesized from the dedicated beams of all UEs located within the beam, and the synthesized narrow beam may be used when transmitting the PTM bearer within the coverage area of the beam. And generating a set of beams for transmitting the PTM bearer according to the processing. The set consists of recorded beams that are replaced by dedicated beams for a UE when there is only one UE in a recorded beam, and by a narrow beam when included in a recorded beam that covers the UE.

In the process of sending the PTM bearer, a beam set for sending the PTM bearer needs to be dynamically adjusted according to a change in a location of a UE receiving the bearer. If the number of the UE in the coverage area of one beam is changed from one to a plurality along with the change of the position of the UE, the beam or the synthesized narrow beam is adopted when the PTM bearer is sent in the coverage area of the beam; if the number of the UE in one beam coverage area is changed from a plurality of UE to one UE along with the change of the position of the UE, when the PTM bearer is sent in the beam coverage area, the special beam of the UE left in the area is adopted; if the UE in a beam coverage area is dispersed in the beam coverage area from being concentrated in a certain direction along with the change of the position of the UE, the beam is adopted when the PTM bearer is sent in the beam coverage area; if the UE in a beam coverage area changes from being dispersed in the area to being intensively distributed in a narrow direction along with the change of the position of the UE, adopting a synthesized narrow beam when the PTM bearer is sent in the beam coverage area; if the number of the UE in one wave beam coverage area is changed from 0 to non-0 along with the position change of the UE, newly adding the PTM bearer transmitted in the wave beam coverage area, and according to the number and the distribution condition of the UE in the wave beam coverage area, adopting a special wave beam, a synthesized narrow wave beam or the wave beam of the UE when the PTM bearer is transmitted in the newly added wave beam coverage area, and putting the wave beam adopted when the PTM bearer is transmitted in the newly added wave beam coverage area into a wave beam set for transmitting the PTM; and if the number of the UE in one beam coverage area is changed from non-0 to 0 along with the position change of the UE, stopping transmitting the PTM bearer in the beam coverage area, and removing the beam corresponding to the area from a beam set for transmitting the PTM bearer.

S1053: splitting each active PTM bearer into K for that bearer at each cell transmitting the service₁+1 sub-PTM bearers.

Wherein, K₁The number of RBs having a fixed amount of data transmitted at a time and transmitted periodically among the RBs generated for the service,using P-RB to represent RB with periodic transmission and fixed data quantity of each transmission, using NP-RB to represent other RBs, each P-RB having a sub PTM bearing for transmitting the P-RB to UE in PTM mode, using P-PTM bearing to represent sub PTM bearing of P-RB, the rest sub PTM bearing being used for transmitting other (K-K) of the service in PTM mode₁) Transmitting RB to UE, using NP-PTM bearing to represent the sub PTM bearing, when K₁When the number of RBs is equal to 0, each PTM bearer is split into unique sub PTM bearers for transmitting all RBs of the service to the UE in a PTM manner.

S1054: in each cell transmitting the service, for each active PTM bearer, the MAC layer allocates radio resources for each sub PTM bearer of the PTM bearer on the BWP where the bearer is located, and transmits each sub PTM bearer through the allocated resources.

And for the service, uniformly allocating a G-RNTI for the service according to the description in S102, and when at least one P-RB exists in the RBs generated by the service, uniformly allocating an SPS G-RNTI for the service.

In each cell transmitting the service, for each activated PTM bearer, determining the BWP in which the bearer is located, and allocating PDSCH resources to each sub PTM bearer on the BWP for transmitting PDSCH, wherein the sub PTM bearers are carried on the PDSCH.

In each cell for transmitting the service, for each activated PTM bearer, determining the BWP in which the bearer is located, and allocating PDCCH resources to each sub PTM bearer in CORESEET and search space configured on the BWP for sending PDCCH, wherein the DCI format on the PDCCH is the dynamic scheduling information or the activation/deactivation information of semi-static resources of the sub PTM bearer.

In each cell transmitting said service, for each active PTM bearer, when K₁When not 0, the PTM carries K₁A k1 th P-PTM bearer is used for transmitting a k1 th P-RB in a PTM mode. One of K RLC entities of the PTM bearer is connected to the PDCP entity of the K1 th P-RB, and the RLC entity transmits the generated RLC PDU to the MAC layer through the connected SC-MTCH. The MAC layer allocates PDSCH resources to the k1 th P-PTM bearing and allocates the PDSCH resources according to the allocationAnd the PDSCH resource assembles TB from RLC PDU on the SC-MTCH, and transmits PDSCH through the allocated PDSCH resource, wherein the TB is carried on the PDSCH.

In each cell transmitting said service, for each active PTM bearer, when K-K₁And when the number of the NP-RB is not 0, the PTM carries one NP-PTM bearer, and the bearer is used for transmitting all NP-RBs of the PTM bearer in a PTM mode. For each NP-RB, one RLC entity in K RLC entities carried by the PTM is connected with a PDCP entity of the NP-RB, and the RLC entity transmits the generated RLC PDU to the MAC layer through the connected SC-MTCH. The MAC layer receives the above (K-K)₁) NP-RB through (K-K)₁) RLC PDUs of SC-MTCH transmission. The MAC layer allocates PDSCH resources to the NP-PTM bearer and uses the (K-K) resources according to the allocated PDSCH resources₁) And RLC PDUs on the SC-MTCH assemble TBs, and transmit PDSCHs through allocated PDSCH resources, wherein the TBs are borne on the PDSCHs.

In each cell transmitting the service, for each active PTM bearer, the method of transmitting each sub PTM bearer of the bearer in more detail is as follows:

determining the number M1 of beams in the beam SET SET for transmitting the PTM bearer.

For each P-PTM bearer of the PTM bearers, the MAC layer at least allocates one semi-static resource for the P-PTM bearer, wherein each semi-static resource is used for periodically sending the P-PTM bearer and informing the configuration information of the at least one semi-static resource to each RRC connection state UE receiving the PTM bearer through dedicated signaling.

When a plurality of semi-static resources are configured for the P-PTM bearer, only one activated semi-static resource is used for transmitting the P-PTM bearer in the same time period. And in the process of transmitting the P-PTM bearer, informing the UE receiving the P-PTM bearer of the activated semi-static resources in the current time period through a DCI format on the PDCCH scrambled by the SPS G-RNTI through CRC.

Specifically, the MAC layer allocates M1 × T1 PDCCH occasions to the PDCCH, and allocates CCE resources to the PDCCH in each time slot, and the CCE resources in each PDCCH time slot may be the same or different. The MAC layer divides M1T 1 occasions into T1 groups, each group consists of continuous M1 PDCCH occasions, the PDCCH is transmitted by adopting the beams in the beam SET SET borne by the PTM in turn in the M1 PDCCH occasions included in each group, and the PDCCH adopts the distributed CCE resources when being transmitted in each occasion. T1 is the number of times of repeated transmission of P-PTM bearing.

And transmitting the semi-static resource borne by the P-PTM in each period, wherein the semi-static resource borne by the P-PTM consists of M1 × T1 continuous PDSCH occasions, the MAC layer allocates the same resource to the PDSCH in each occasion, the PDSCH bears corresponding P-RB, and the PDSCH adopts SPS G-RNTI during bit scrambling. Dividing M1 × T occasions into T1 groups, each group consists of continuous M1 PDSCH occasions, and sequentially adopting the beams in the beam SET SET borne by the PTM to transmit the PDSCH in the M1 PDSCH occasions included in each group, wherein the PDSCH adopts allocated resources when transmitting in each occasion. In different periods, the value of M1 may be different, but the resources allocated to PDSCH in each PDSCH occasion in different periods are the same, the starting point for transmitting the P-PTM bearer in different periods is the same, and the maximum number of PDSCH occasions in each period is M × T1.

When the TB needs to be retransmitted on the PDSCH, the MAC layer allocates PDCCH resources and PDSCH resources for the TB, wherein the PDCCH resources consist of M1T 1 PDCCH occasions, and the PDSCH resources consist of M1T 1 PDSCH occasions. And transmitting the PDCCH scrambled by the SPS G-RNTI by the CRC in each PDCCH opportunity by adopting the allocated PDCCH resource. Each PDCCH time corresponds to the only PDSCH time according to the time sequence relation, different PDCCH times correspond to different PDSCH times, and the DCI format on the PDCCH sent in each PDCCH time is the dynamic scheduling information of the PDSCH in the corresponding PDSCH time. And transmitting the PDSCH by adopting the allocated PDSCH resources in each PDSCH opportunity, wherein the PDSCH is provided with a retransmitted TB, and the PDSCH adopts SPS G-RNTI when in bit scrambling. The method for sending PDCCH/PDSCH by using the beam in the beam SET SET is the same as above, and is not described again.

For the NP-PTM bearer of the PTM bearer, the MAC layer dynamically allocates PDCCH resources and PDSCH resources for the NP-PTM bearer each time the NP-PTM bearer is sent, wherein the PDCCH resources consist of M1T 2 continuous PDCCH occasions, and the PDSCH resources consist of M1T 2 PDSCH occasions. T2 indicates the number of NP-PTM bearer retransmissions.

CCE resources are allocated to the PDCCH in each PDCCH time machine, the same CCE resources can be allocated to the PDCCH in different PDCCH time machines, and different CCE resources can also be allocated. The PDSCH may be allocated the same resources or different resources at each PDSCH occasion. Each PDCCH time corresponds to a unique PDSCH time according to a time sequence relation, different PDCCH times correspond to different PDSCH times, the DCI format on the PDCCH transmitted in one PDCCH time is the dynamic scheduling information of the PDSCH transmitted in the corresponding PDSCH time, the CRC of the PDCCH is scrambled by G-RNTI, and the PDSCH adopts the G-RNTI when bits are scrambled.

And dividing the PDCCH occasions into T2 groups, wherein each group consists of continuous M1 PDCCH occasions, the PDCCH is sequentially transmitted by adopting the beams in the beam SET SET carried by the PTM in the M1 PDCCH occasions included in each group, and the PDCCH adopts the distributed CCE resources when being transmitted in each occasion.

And dividing PDSCH occasions into T2 groups, wherein each group consists of continuous M1 PDSCH occasions, the PDSCH is sequentially transmitted by adopting the beams in the beam SET SET borne by the PTM in the M1 PDSCH occasions included in each group, and the PDSCH adopts allocated resources when being transmitted in each occasion.

The value of M1 may be different each time the P-PTM/NP-PTM bearer is sent. But the maximum value of M1 is M.

Fig. 5 is a fourth schematic flow chart of a method for transmitting a multicast broadcast service in an NR cell according to the present invention, and in the method for transmitting a multicast broadcast service in an NR cell according to the present invention shown in fig. 2 and fig. 3, in S105, in a cell in which the service is transmitted, when there is at least one active PTP bearer, for each active PTP bearer, a specific method for a MAC layer to transmit the bearer on a BWP in which the bearer is located is shown in fig. 5, and specifically includes the following processes:

s1055: in the cell for transmitting the service, for each activated PTP bearer, determining the UE using the bearer, and sending the configuration information of the bearer, the configuration information of the corresponding PTM bearer and the configuration information of DL BWP of the UE to the UE using the bearer through a dedicated signaling; the corresponding PTM bearer is used for transmitting the service, is in an inactive state, and is positioned on the same MBS special BWP with the PTP bearer.

Since the contents of some items in the configuration information of the two bearers are the same, preferably, the configuration information of the PTM bearer transmitted to the UE only includes items with different contents.

S1056: at each cell, for each active PTP bearer, the MAC layer determines the BWP that sent the PTP bearer, which is sent on the corresponding BWP.

Specifically, for each active PTP bearer, the specific method of transmitting the bearer differs according to the active DL BWP of the UE using the bearer.

Scene one: for an active PTP bearer, determining the UE using the bearer, and when the active DL BWP of the UE is MBS-dedicated BWP, transmitting the PTP bearer on the BWP.

In scenario one, for each P-RB in the PTP bearer, the method for the MAC layer to send the P-RB is the existing method, and is not described again.

In scenario one, for NP-RBs in the PTP bearer, the MAC layer carries DTCHs corresponding to these NP-RBs and DTCHs corresponding to other NP-RBs of the UE through the same DL-SCH. Specifically, the method for transmitting each DTCH through the DL-SCH is an existing method, and is not described again.

Scene two: for an active PTP bearer, determining a UE using the bearer, and when the active DL BWP of the UE is a general BWP, transmitting the PTP bearer in one of the following manners:

the first method is as follows: transmitting the PTP bearer on MBS-specific BWP included in general BWP

In this way, the sending method for sending each P-RB in the PTP bearer is an existing method, and is not described again.

In this way, the MAC layer carries the DTCH corresponding to the NP-RB in the PTP bearer through the same DL-SCH. Specifically, the method for transmitting each DTCH through the DL-SCH is an existing method, and is not described again.

The second method comprises the following steps: transmitting the PTP bearer on a generic BWP

The method for sending the P-RB carried by the PTP in the mode is the existing method and is not described in detail.

In this way, the MAC layer carries DTCH corresponding to NP-RB in the PTP bearer and DTCH corresponding to other NP-RB of the UE through the same DL-SCH. Specifically, the method for transmitting each DTCH through the DL-SCH is an existing method, and is not described again.

Fig. 6 is a flowchart illustrating a fifth method for transmitting a multicast broadcast service in an NR cell according to the present invention, where, on the basis of the method for transmitting a multicast broadcast service in an NR cell proposed by the present invention shown in fig. 2, 3, 4, and 5, in S106, for each RRC connected UE that receives the service only through an active PTM bearer, a PTP bearer of the UE is in an inactive state, and in S106, a method for dynamically switching a transmission mode of the service on a BWP that transmits the PTM bearer by using a MAC layer for the UE is shown in fig. 6, and specifically includes the following processes:

s1061: when the MAC layer determines that the service is transmitted through the PTP bearer of the UE according to the related information, the PTP bearer is activated; and when the MAC layer determines that one or more RBs of the service are transmitted through the PTP bearer of the UE according to the related information, each RB which needs to be transmitted in a PTP mode in the PTP bearer of the UE is activated.

Specifically, in the process of transmitting the service through the PTM bearer, the MAC layer determines, according to the related information from the physical layer, the related information from the RRC layer, and the related information obtained by itself: whether the service needs to be transmitted through a PTP bearer of the UE, and whether corresponding RBs of the service need to be transmitted through one or more RBs in the PTP bearer.

Such as: the MAC layer can determine which P-RB receiving quality of the UE does not meet the BLER requirement according to the feedback information of the UE, and can also determine whether the NP-RB receiving quality of the service meets the BLER requirement or not. When one P-RB of the service does not meet the BLER requirement, the MAC layer may activate the corresponding RB in the PTP bearer of the UE. When the NP-RB of the service does not meet the BLER requirement, the MAC layer can activate all NP-RBs in the PTP bearer of the UE. However, if only one NP-RB in the service is transmitted in a certain time period, the MAC layer may only activate the corresponding NP-RB in the PTP bearer of the UE when determining that the NP-RB in the time period does not satisfy the BLER requirement according to the feedback information.

For another example: the MAC layer may also activate all RBs in the PTP bearer of the UE according to related messages from the RRC layer. Such as: when the UE is located at the cell edge, the UE may report a measurement report to the base station, and after receiving the measurement report of the UE, the RRC layer of the cell may notify the MAC layer through related information before switching the UE to the target cell: the UE is at the cell edge. The MAC layer may activate all RBs in the PTP bearer of the UE after receiving the message. And then transmitting the service through a PTP bearer so as to ensure the receiving quality of the UE to the service at the edge of the cell.

When a PTP bearer is activated, each RB of the bearer is activated.

S1062: for each activated RB, the RLC entity associated with the RB in the PTP bearer of the UE determines the subscript of the first PDCP PDU to be transmitted, extracts the PDCP PDU from the data storage area from the PDCP PDU, performs corresponding processing, and transmits the generated RLC PDU to the MAC layer through the corresponding DTCH.

Specifically, on a BWP transmitting said service, for each RB of said service, each active PTM/PTP located on the BWP carries an RLC entity associated with the RB, which RLC entities share a data storage area. Each RLC entity extracts PDCP PDUs from the corresponding data storage area for assembling RLC PDUs while storing a number of necessary parameters for that RLC entity in the data storage area, wherein there is a parameter INDEX for indicating the INDEX of the next PDCP PDU to be extracted for that RLC entity.

When the inactive PTM/PTP bearer shares the RLC entity or the inactive PTM/PTP bearer shares the RLC entity resource pool, the RLC entity is not configured for the inactive PTM/PTP bearer. Therefore, when an inactive PTM/PTP bearer is activated or at least one RB in an inactive PTM/PTP bearer is activated, the MAC layer needs to trigger the RLC layer to configure the RLC entity for the bearer. The method for configuring the RLC entity for the corresponding bearer by the RLC layer is described in S103, and is not described again.

For each activated RB in the PTP bearer of the UE, the RLC entity associated with the RB inquires an INDEX stored in a corresponding data storage area by the PTM bearer in the storage area, and the RLC entity extracts the PDCP PDU from the PDCP PDU indicated by the INDEX in the data storage area for assembling the RLC PDU and transmits the generated RLC PDU to the MAC layer through DTCH.

S1063: for the UE, if the parameters of the DRX mode configured to the UE by the MAC layer before are changed due to the fact that the activated RBs in the PTP bearer of the UE are transmitted, the MAC layer sends MAC CE in advance for transmitting the new DRX mode to the UE; the MAC layer transmits each activated RB to the UE based on the new DRX mode after the new DRX mode is enabled.

The parameters of the DRX mode include: DRX period, radio frame offset, time slot offset, ON-DURATION timer, inactivity timer, etc. And the UE monitors the PDCCH scrambled by the C-RNTI for the CRC from the time slot indicated by the time slot offset in the radio frame indicated by the radio frame offset in each DRX period according to the configured DRX mode, and receives the corresponding PDSCH according to the DCI format on the PDCCH to acquire the corresponding service when monitoring the corresponding PDCCH.

When the activated RB is the P-RB, the method for transmitting the P-RB in the PTP bearer by the MAC layer is as above. And when the activated RB is NP-RB, the method for transmitting the NP-RB in the PTP bearer by the MAC layer is as above.

S1064: in the process of transmitting the service through the PTP bearer, when the MAC layer determines to suspend transmitting a certain RB or some RBs or all RBs through the PTP bearer according to the related information, the RBs enter an inactive state from an active state, and the MAC layer informs RLC entities corresponding to the RBs.

Specifically, the MAC layer makes a decision of transmission mode switching based on the related information. Some examples are given below.

When the MAC layer finds that resources on the current BWP are insufficient and requires more resources for transmitting the corresponding PTP bearer than the MBS with the higher priority of the service, the MAC layer may stop transmitting the service through the PTP bearer and release the resources dedicated to the PTP bearer of the service to the MBS with the higher priority.

The MAC layer may also deactivate all RBs in the PTP bearer of the UE according to the related message from the RRC layer. Such as: when the RRC layer reports that the quality of the wireless channel of the UE is changed from poor to good according to the measurement of the UE, the RRC layer of the cell issues related information to the MAC layer to indicate that: the quality of the radio channel of the UE becomes good, and the MAC layer can deactivate all RBs of the PTP bearer of the UE after receiving the message of the RRC layer.

S1065: each notified RLC entity inquires about INDEX stored in the corresponding data storage area by PTM bearer in the storage area, and if the notified RLC entity finds that a plurality of PDCP PDUs before the PDCP PDU corresponding to the INDEX are not transmitted by the notified RLC entity, the notified RLC entity transmits 'indication of slow speed' to the MAC layer. And then the RLC entity continues to send the PDCP PDUs which are not transmitted to the MAC layer through the corresponding DTCH. After transmitting all untransmitted PDCP PDUs to the MAC layer, the RLC entity stops transmitting the RLC PDUs to the MAC layer through the DTCH. When no RLC entity is configured for an inactive PTM/PTP bearer, the status of the RLC entity will become "idle" and the RLC entity will disconnect from the corresponding DTCH.

S1066: after receiving an RLC entity 'slow speed indication', the MAC layer may raise the scheduling priority of the RB in the PTP bearer, and preferentially schedule radio resources for the RB, so as to transmit PDCP PDUs, which have not been transmitted in the RB, to the UE through the PTP bearer as quickly as possible.

Fig. 7 is a flowchart illustrating a sixth method for transmitting a multicast broadcast service in an NR cell according to the present invention, where, on the basis of the method for transmitting a multicast broadcast service in an NR cell according to the present invention shown in fig. 2, fig. 3, fig. 4, and fig. 5, in S106, there is an inactive PTM bearer on a BWP transmitting the service, a few RRC connected UEs receive the service through respective active PTP bearers on the BWP, and as more RRC connected UEs receive the service on the BWP, the method for the MAC layer to dynamically switch the transmission mode of the service for each RRC connected UE on the BWP is as follows:

SS 1061: for the BWP, whenever the number of RRC connected UEs receiving the service on the BWP increases or the location of the existing UE receiving the service changes, the MAC layer evaluates whether to activate the PTM bearer in the inactive state configured for the service by the BWP. And when the MAC layer determines to activate the PTM bearer through evaluation, if the RLC entity is not configured for the PTM bearer, the MAC layer triggers the RLC layer to configure the RLC entity for the PTM bearer.

When the MAC layer triggers the RLC layer to configure the RLC entities for the PTM bearer, the RLC layer selects K idle RLC entities for the PTM bearer from the shared RLC entities or from a shared RLC entity resource pool under the triggering of the MAC layer, configures the K RLC entities for the PTM bearer, and configures the kth RLC entity by adopting the kth group of RLC parameters of the bearer, wherein the RLC entity is upwards connected with the PDCP entity of the kth RB and downwards connected with the kth SC-MTCH of the K SC-MTCHs of the PTM bearer.

SS 1062: each RLC entity of the PTM bearer extracts the parameter INDEX saved in the data storage area by each activated PTP bearer from the corresponding data storage area, selects the PDCP PDU generated earliest from the PDCP PDUs indicated by each INDEX, extracts the PDCP PDU from the data storage area from the PDCP PDU for assembling the RLC PDU, and sends the assembled RLC PDU to the MAC layer through SC-MTCH.

SS 1063: the MAC layer receives the PTM bearer RLC PDUs transmitted through the respective SC-MTCH.

SS 1064: the MAC layer sends the PTM bearer on the BWP. Before transmitting the PTM bearer, the MAC layer transmits MAC CE to each UE which receives the service on the BWP through PTP bearer, and the following information is indicated through the MAC CE:

(1) the PTM bearer in the inactive state configured on the BWP is activated

(2) DRX mode adopted by PTM bearing

Already stated in the above S105: in order to enable the UE to receive the service through the activated PTP bearer and subsequently receive the service through the PTM bearer, the configuration information of the PTP bearer of the UE and the configuration information of the non-activated PTM bearer configured on the same BWP are transmitted to the UE together through dedicated signaling.

Therefore, when the PTM bearer in the inactive state is activated, the UE does not need to be configured with information of the bearer, and only needs to notify the UE of the DRX mode adopted by the PTM bearer through the MAC CE.

SS 1065: and in the process of transmitting the service through the PTM bearer, the MAC layer gradually stops transmitting the service to each UE through the PTP bearer. And for the PTP load stopping transmitting the service, the MAC layer triggers the PTP loads to enter an inactive state. For each PTP bearer entering the inactive state, when no RLC entities are configured for the inactive PTM/PTP bearer, the K RLC entities occupied by each PTP bearer stopping transmitting the service enter an idle state.

SS 1066: in the process of transmitting the service through the PTM bearer, the MAC layer determines whether some or all RBs in the PTP bearer of one UE need to be activated or not through related information. For each activated RB in a PTP bearer, the MAC layer transmits the RB over the PTP bearer.

SS 1067: in the process of transmitting the service through the PTM bearer, the MAC layer dynamically determines a beam SET SET for sending the PTM bearer through related information. When the number of beams included in the beam set for transmitting the PTM bearer is M1 ═ 0, the MAC layer triggers the bearer to enter an inactive state. When the RLC entities are not configured for the inactive bearer, the MAC layer also triggers K RLC entities occupied by the PTM bearer in the RLC layer to enter an idle state.

Specifically, for an active PTM bearer, on the BWP transmitting the bearer, the MAC layer dynamically determines the SET of beams SET transmitting the PTM bearer according to the location of the UE receiving the bearer.

When all RBs in a PTP bearer configured for a UE on the BWP are activated, optionally, the UE is deleted from the set of UEs receiving the PTM bearer when determining the set of beams to transmit the PTM bearer.

As the number of UEs in the set of UEs receiving the PTM bearer decreases, when: when all the UEs receiving the service on the BWP adopt their PTP bearers to receive the service, the set of UEs receiving the bearers will become an "empty set", in which case the MAC layer triggers the PTM bearer to enter an "inactive state". The MAC layer may switch the state of the corresponding bearer by setting a state variable of each PTM/PTP bearer. When the RLC entities are not configured for the inactive bearer, the MAC layer also triggers K RLC entities occupied by the PTM bearer in the RLC layer to enter an idle state.

Before describing in detail the transmission method of the multicast broadcast service in the NR cell shown in fig. 2 at S107, the relationships among the active PTM bearers, inactive PTM bearers, active PTP bearers and inactive PTP bearers in the method are summarized as follows:

in a cell, configuring an activated PTM bearer for an MBS on an MBS special BWP, and configuring an inactivated PTP bearer for each UE receiving the bearer for transmitting the MBS; configuring an inactive PTM bearer on an MBS-dedicated BWP for transmitting the service while configuring an active PTP bearer for a UE receiving the service on the BWP.

In the same cell, the PTM bearers configured for the same MBS have the same basic configuration information and different BWP configuration information.

PTM bearers of the same BWP for transmitting the same service in different cells have the same basic configuration information, except for DRX mode.

PTP bearers configured for the same UE in different cells have the same basic configuration information. When two PTP bearers are located on the same BWP of different cells, the two PTP bearers have not only the same basic configuration information but also the same BWP configuration information in addition to the DRX mode.

Fig. 8 is a flow diagram of a seventh flow of a transmission method of a multicast and broadcast service in an NR cell provided by the present invention, based on the above summary, in the transmission method of a multicast and broadcast service in an NR cell provided by the present invention shown in fig. 2 to fig. 7, in S107, in a transmission process of the service, for each RRC connected UE receiving the service, in a process that the UE moves from a source cell to a target cell, a method of transmitting the service to the UE through a corresponding bearer in the target cell through signaling interaction between the source cell and the target cell is as shown in fig. 8, and specifically includes the following processes:

s1071: and when the source cell determines to execute the switching according to the received measurement report of the UE, executing corresponding processing and sending an RRC switching request message to the target cell.

Specifically, when the RRC layer of the source cell determines to perform handover according to the received measurement report of the UE, if the PTP bearer of the UE is not activated yet, the RRC layer immediately issues a message to activate the PTP bearer of the UE to the MAC layer of the cell, and the MAC layer immediately activates the PTP bearer of the UE according to the message and transmits the service through the bearer.

Then, the source cell transmits the following information to the target cell through a handover request message.

(1) Information related to the service currently being received by the UE

The information specifically includes:

1) TMGI, session ID, G-RNTI and SPS G-RNTI of the service

2) ID of MBS-specific BWP where PTP bearer of UE is located

When the target cell does not transmit the MBS in PTM/PTP load

3) Basic configuration information of PTP bearer of UE

4) Basic configuration information of PTM bearer of the service on BWP where PTP bearer of UE is located

(2) C-RNTI and SPS C-RNTI of UE

(3) When UE receives common service at the same time, configuration information related to common service

(4) Other handover-related information

S1072: and after receiving the switching request message, the target cell executes corresponding processing and feeds back a switching request confirmation message to the source cell.

S1073: and the source cell sends RRC reconfiguration information (switching command) to the UE according to the received switching request confirmation information, the UE establishes a corresponding bearer according to the RRC reconfiguration information, and the service is received in the target cell through the established bearer.

Specifically, after receiving the handover request message, the target cell performs different processing according to different support conditions of the target cell for the service. Specifically, the target cell has three support cases for the service, where the target cell performs different processes under different conditions, and the content included in the handover request acknowledgement message sent to the source cell is also different. Accordingly, after receiving the handover request confirm message, the source cell may send RRC reconfiguration information to the UE with different contents according to the different contents of the message. Accordingly, the UE performs different processes according to different message contents after receiving the RRC reconfiguration message.

Specifically, the supporting situations of the target cell for the service are divided into the following three situations:

(1) target cell transmitting said service via at least one active PTM bearer

(2) The target cell does not configure the activated PTM bearer for the service, and the service is transmitted only through the activated PTP bearer

(3) The target cell has not transmitted the service

The processing performed by the target cell in S1072, the processing performed by the source cell in S1073, and the processing that the UE needs to perform as mentioned in S1073 will be described in detail for each case.

The first condition is as follows: target cell transmitting said service via at least one active PTM bearer

In which case the target cell performs the following:

(1) one BWP is selected among BWPs in which each active PTM is located, and PTP bearers are configured to the UE on the BWP so that the PTM/PTP handover can be performed immediately after the UE moves to the target cell.

Specifically, the target cell selects one BWP from among the BWPs in which the active PTM is located. If the ID of one BWP is the same as the ID of the BWP in the handover request, the target cell preferentially selects the BWP.

The target cell configures PTP bearer for the UE on the selected BWP, so that the UE receives the service through the bearer after being switched to the target cell. If the UE has normal services, the normal services of the UE are configured on the MBS dedicated BWP or a general BWP of the BWP.

(2) The target cell stores the TMGI, the session ID, the G-RNTI, the SPS G-RNTI, the C-RNTI and the SPS C-RNTI in the handover request.

(3) The target cell sends a switching request confirmation message to the source cell, and the message carries the following information:

1) ID of MBS-specific BWP where PTP bearer of UE is located

2) PTM bearer activation indication: and the method is used for indicating that the PTM bearer for transmitting the same service on the BWP where the PTP bearer of the UE is located is in an activated state, so that the UE receives the PTP bearer and the PTM bearer at the same time in the target cell.

3) DRX mode for PTP bearers

4) DRX mode for PTM bearer

5) Configuration information related to ordinary service (if the UE also receives ordinary service)

6) Other configuration information

In this case, when receiving the handover request acknowledge message, the source cell sends an RRC reconfiguration message (handover command) to the UE, where the message carries the following information:

(1) ID of MBS-specific BWP: BWP ID to indicate receiving MBS

(2) Receiving a PTP bearing indication: instructing the UE to receive the PTP bearer on the BWP indicated by the BWP ID of the target cell

(3) Receiving a PTM bearer indication: instructing the UE to receive the PTM bearer on the BWP indicated by the BWP ID in the target cell

(4) Configuration information of MBS dedicated BWP: if the BWP ID is different from the ID of the MBS BWP in the switching request, the source cell transmits the configuration information of the MBS special BWP corresponding to the BWP ID to the UE so that the UE receives PTP load and PTM load on the corresponding BWP at the target cell.

(5) DRX mode for PTP bearers

(6) DRX mode for PTM bearer

(7) Configuration information related to ordinary service (if the UE also receives ordinary service)

(8) Other configuration information

After receiving the message, the UE executes the following processing:

(1) and the UE refreshes the configuration information of the PTP/PTM bearer stored by the UE according to the DRX mode of the PTP/PTM bearer.

(2) When the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the 'configuration information of the MBS special BWP' in the message.

(3) And after the handover to the target cell, the UE receives the PTP bearer and the PTM bearer on the corresponding BWP according to the refreshed configuration information of the PTP/PTM bearer.

(4) And the UE continues to receive the common service after being switched to the target cell according to the configuration information related to the common service in the message.

Case two: the target cell does not configure the activated PTM bearer for the service, and the service is transmitted only through the activated PTP bearer

In this case, the target cell performs the following processing:

(1) one BWP is selected from these BWPs. If the ID of one BWP is the same as the ID of the BWP in the handover request, the target cell preferentially selects the BWP.

(3) The target cell sends a handover request acknowledge message to the source cell. The following information is carried in this message:

1) ID of MBS-specific BWP where PTP bearer of UE is located

2) DRX mode for PTP bearers

3) Configuration information related to ordinary service (if the UE also receives ordinary service)

4) Other configuration information

(1) ID of MBS-specific BWP: BWP ID to indicate receiving MBS

(3) Configuration information of MBS dedicated BWP: if the BWP ID is different from the ID of the MBS BWP in the switching request message, the source cell transmits the configuration information of the MBS special BWP corresponding to the BWP ID to the UE so that the UE receives PTP load and PTM load on the corresponding BWP on the target cell.

(4) DRX mode for PTP bearers

(5) Configuration information related to ordinary service (if the UE also receives ordinary service)

(6) Other configuration information

After receiving the message, the UE executes the following processing:

(1) and the UE refreshes the configuration information of the PTP bearer stored by the UE according to the 'DRX mode of the PTP bearer' in the switching request.

(2) When the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the 'configuration information of the MBS special BWP' in the message. And, deleting 'DRX mode of PTM bearer' from the refreshed configuration information of PTM bearer.

(3) And after the handover to the target cell, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by the UE. And, prepare to receive PTM bearing in the target cell according to the configuration information of PTM bearing that oneself is refreshed.

Case three: the target cell has not transmitted the service

In this case, the target cell performs the following processing:

(1) selecting a BWP from MBS special BWP, configuring activated PTP load for UE on the BWP, and configuring non-activated PTM load for the service; when the PTP bearer is configured for the UE, taking 'PTP bearer basic configuration information' in the switching request as basic configuration information of the PTP bearer configured for the UE; when configuring PTM load bearing for the service, using the PTM load bearing basic configuration information in the switching request as the basic configuration information of the PTM load bearing; determining the configuration information of the BWP in the configuration information of the PTP/PTM bearer according to the configuration information of the selected BWP; if the UE has common service, configuring the common service of the UE on the MBS special BWP or a certain universal BWP of the BWP;

(3) The target cell determines the session of the MBS needing 5GC transmission according to the 'TMGI and the session ID of the MBS' in the switching request, and triggers the 5GC to transmit the control plane information and the user plane data of the service to the target cell through a control plane interface and a user plane interface respectively by the control plane interface between the target cell and the 5 GC.

(4) The target cell sends a handover request acknowledge message to the source cell. The following information is carried in this message:

1) ID of MBS-specific BWP where PTP bearer of UE is located

2) DRX mode for PTP bearers

4) Other configuration information

(1) ID of MBS-specific BWP: BWP ID to indicate receiving MBS

(4) DRX mode for PTP bearers

(6) Other configuration information

After receiving the message, the UE executes the following processing:

(1) and the UE refreshes the configuration information of the PTP bearer stored by the UE according to the DRX mode of the PTP bearer in the message.

(2) When the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the 'configuration information of the MBS special BWP' in the message. And deleting ' DRX mode of PTM bearer ' in the refreshed configuration information of PTM bearer '.

(3) After switching to the target cell, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by itself. And the UE prepares to receive the PTM bearer in the target cell according to the configuration information of the PTM bearer refreshed by the UE.

In the method for maintaining MBS continuity in an NR cell according to the present invention shown in fig. 2 to 8, in S107, in order to ensure that the UE maintains lossless reception of the service during handover to the target cell, in the UE handover process described in S107, the following method is adopted to ensure that lossless data transmission is performed between the source cell and the target cell for the service, and specifically includes the following steps:

when the target cell receives the handover request sent by the source cell, for the MBS being received by the UE, if the target cell transmits the service by PTM bearer and/or PTP bearer, the target cell and the source cell execute S901: otherwise the target cell and the source cell execute S902.

S901 includes the following processing procedures:

when a target cell receives a switching request sent by a source cell, for an MBS being received by UE, if the target cell transmits the service by PTM bearing and/or PTP bearing, for each RB of the MBS, only newly generated PDCP PDU is placed in a data storage region of the RB from the current moment, even if a certain PDCP PDU is transmitted to an MAC layer through all connected RLC entities, the PDCP PDU is not deleted from the storage region. It doesDetermining SN of PDCP PDU generated earliest in storage area of kth RB by TSN_kThe SN is represented. Transmitting K SNs to a source cell through a handover request acknowledgement message, the K SNs being: TSN_k，k＝1,……,K。

After receiving the handover request acknowledge message, the source cell determines, for the UE in the handover process, a parameter INDEX stored in a storage area of a kth RLC entity in a PTP bearer of the UE in the kth RB. By SSN_kRepresents the SN of the PDCP PDU to be extracted next by the kth RLC entity.

If SSN_kCorresponding PDCP PDU generation time is earlier than TSN_kCorresponding PDCP PDU shows that the transmission speed of the PDCP PDU of the kth RB in the PTP load of the UE in the source cell is later than that of the same RB in the target cell, and STSN is used_kDenotes SN as TSN_kThe source cell is SSN from SN in the storage area corresponding to the kth RB_kThe PDCP PDUs start to extract each PDCP PDU until the SN is extracted as STSN_kThe PDCP PDU of (1). These extracted PDCP PDUs are forwarded to the target cell.

If SSN_kCorresponding PDCP PDU generation time later than TSN_kAnd when the UE is in the corresponding PDCP PDU, the transmission speed of the PDCP PDU of the kth RB in the PTP bearer of the UE in the source cell is higher than that of the same RB in the target cell, and the source cell does not need to forward the corresponding PDCP PDU for the lossless reception of the kth RB in the scene.

For the forwarded PDCP PDUs of the kth RB, in the target cell, the kth RLC entity in the PTP bearer of the UE preferentially transmits the forwarded PDCP PDUs to the MAC layer, so that the MAC layer preferentially transmits the forwarded PDCP PDUs. After the transmission of the forwarded PDCP PDU is completed, the RLC entity starts to transmit the PDCP PDU in the corresponding data storage area. The method can ensure the lossless transmission of the PDCP PDU in the switching process of the UE.

S902 includes the following processing procedures:

when the target cell receives the switching request sent by the source cell, for the MBS being received by the UE, if the target cell does not transmit the service, the target cell carries "NoData" in the switching request message, where the NoData is 0 and is used to indicate that the target cell has not transmitted the MBS.

After receiving the handover request confirmation message, when the message "NoData ═ 0", for the UE in the handover process, the source cell determines the parameter INDEX stored in the storage area of the kth RB by the kth RLC entity in the PTP bearer of the UE, and uses the SSN_kRepresents the SN of the PDCP PDU to be extracted next by the kth RLC entity.

For each RB in the PTP bearer of the UE, the source cell forwards PDCP PDUs stored in a data storage area of the RB to the target cell in sequence from the next PDCP PDU to be extracted, and when a new PDCP PDU is put into the storage area, all the newly put PDCP PDUs also need to be forwarded to the target cell in sequence.

And the target cell receives the PDCP PDU of each RB forwarded by the source cell. After the target cell starts receiving the MBS session of the service from the 5GC, the target cell determines the SN of the first PDCP PDU of each RB in the received MBS session. The SN before this SN is denoted as "STOPSN". If the PDCP PDU received from the source cell and forwarded by the RB already comprises the PDCP PDU with the SN of STOPSN, the target cell does not need the source cell to continue forwarding the PDCP PDU of the RB; otherwise, the target cell needs the source cell to continue forwarding the PDCP PDU of the RB until the PDCP PDU with the SN of STOPSN is forwarded to the target cell. The target cell generates a STOP instruction message according to the method, the STOP instruction message carries a parameter STOP, and when the STOP is 1, the target cell indicates that the source cell should immediately STOP forwarding the PDCP PDU; when "STOP ═ 0", the "RB list" is carried in the message, instructing the source cell to forward only PDCP PDUs of individual RBs in the RB list.

When the STOP instruction message is received from the target cell, if the STOP in the message is 1, the source cell immediately STOPs forwarding the PDCP PDU of each RB of the service.

If the STOP in the message is 0, the source cell extracts an RB list formed by K2 sets of parameters carried in the message, and for each set of parameters in the list, the source cell determines the RB to which the PDCP PDU needs to be forwarded continuously according to the RB subscript in the set of parameters; and determining the SN of the last PDCP PDU needing to be forwarded in the PDCP PDUs of the RB according to the STOPSN in the set of parameters.

For each RB to be forwarded, the source cell continues to forward PDCP PDUs from the storage area of the RB until the PDCP PDUs with the SN of STOPSN are completely forwarded. The method can ensure the lossless transmission of the PDCP PDU in the switching process of the UE.

In the above-described methods shown in fig. 2 to fig. 8, in order to uniformly configure the relevant information across the gnbs, an entity MCE may be newly added in the MBS architecture of the NR system, where the MCE is connected to the 5GC for receiving the control plane information of the MBS, and the MCE is further connected to each gNB through a control plane interface. When introducing MCE, the control plane interface between 5GC and gNB is cancelled. The MCE performs related configuration across the gNB and transmits the configuration result and the control plane information of the MBS received from the 5GC to the gNB through the control plane interface.

In the transmission method of the multicast broadcast service in the NR cell shown in fig. 2, S101 and S102 may be implemented by the MCE without making a relevant specification in the 3GPP NR protocol.

Optionally, in the foregoing methods shown in fig. 2 to fig. 8, in order to implement uniform configuration of relevant information across gnbs in an intra-frequency networking scenario, a master node is determined in interconnected gnbs, the master node performs relevant configuration across gnbs in the transmission method for multicast broadcast service in an NR cell according to the present invention, and transmits a configuration result to other gnbs (secondary nodes) through an Xn interface.

Specifically, the unified configuration and corresponding configuration result across the gNB performed by the master node includes:

(1) in a same-frequency networking scene, a main node uniformly configures at least one MBS special BWP for an NR cell transmitting MBS and at least one general BWP for each MBS special BWP, wherein the general BWP includes the MBS special BWP, each MBS special BWP is used for transmitting MBS to RRC connected state UE in a PTM/PTP mode, and for UE receiving MBS on one MBS special BWP, the general BWP of the MBS special BWP is used for bearing the common service of the UE; uniformly configuring a CORESET and a search space for each MBS special BWP, wherein the CORESET and the search space are used for bearing the scheduling information of the MBS, and uniformly configuring the CORESET and the search space for each general BWP of each MBS special BWP, and the CORESET and the search space are used for bearing the scheduling information of the common service; one MBS-specific BWP and the common BWP of the BWP may share the same CORESET and search space.

After the above unified configuration across the gNB is completed, the master node generates configuration information of each MBS-dedicated BWP and configuration information of each general BWP of each MBS-dedicated BWP.

(2) For any MBS, the main node configures an SDAP entity for the service, is used for mapping the QOS flow contained in the MBS conversation of the service to the RB, configures a PDCP entity for each generated RB, and the PDCP entity of each RB generates the PDCP PDU for the RB. The number of generated RBs is denoted by K. And configuring G-RNTI and SPS G-RNTI for the service.

After completing the above processing, the master node generates the following configuration information of the service:

SDAP configuration information: SDAP entity for configuring said service by secondary node

PDCP configuration information: the configuration information of the PDCP entity of each RB generated is used for the secondary node to configure the PDCP entity of each RB of the service;

(3) for any MBS, the main node determines the configuration information of K RLC entities carried by the PTM of the service, and the information is used for configuring the K RLC entities for any PTM of the service;

(4) for any MBS, the main node configures PDSCH parameters and PDCCH parameters for the service, and correspondingly determines PDSCH configuration information and PDCCH configuration information, wherein the PDSCH/PDCCH configuration information is used for the auxiliary node to configure the PDSCH parameters and the PDCCH parameters for the PTM bearer of the service.

The main node transmits the following configuration information to other auxiliary nodes through an Xn interface, so that each NR cell transmitting the service has the same basic configuration information for PTM bearing configured by the service, and the continuous receiving of the service by UE is facilitated when the UE moves among the NR cells.

(1) Configuration information of each MBS-specific BWP, configuration information of each general BWP of each MBS-specific BWP

(2) Basic configuration information of a PTM bearer of an MBS includes:

1) TMGI, Session ID, G-RNTI, SPS G-RNTI

2) SDAP configuration information

3) PDCP configuration information

4) RLC configuration information

5) PDSCH configuration information and PDCCH configuration information.

The invention also provides a transmission system of the multicast broadcast service in the NR cell, which comprises a plurality of interconnected base stations, wherein one base station is used as a main node, and base stations other than the main node are used as auxiliary nodes; wherein, the unified configuration and corresponding configuration result across the gNB executed by the master node includes:

for any MBS, the main node configures an SDAP entity for the service, is used for mapping the QOS flow contained in the MBS conversation of the service to the RB, configures a PDCP entity for each generated RB, and the PDCP entity of each RB generates a PDCP PDU for the RB; the main node generates the following configuration information of the service: SDAP configuration information and PDCP configuration information; and configuring G-RNTI and SPS G-RNTI for the service.

The implementation method and effect of the transmission system of multicast broadcast service in NR cell provided by the present invention are the same as those in the foregoing embodiments, and are not described here again.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for transmitting a multicast broadcast service in an NR cell, comprising:

in the same-frequency networking scene, in each cell for transmitting MBS, at least one MBS special bandwidth part BWP is uniformly configured, and each MBS special BWP is used for transmitting MBS to RRC connection state UE in a PTM/PTP mode; at least one general BWP is uniformly configured for each MBS special BWP, each general BWP contains the MBS special BWP, and for RRC connected UE receiving MBS on one MBS special BWP, the general BWP of the BWP is used for bearing common service of the UE;

for a broadcast/multicast service, configuring a service data adaptation protocol SDAP entity for the service, and mapping each service quality QOS flow included in the MBS session of the service to a radio bearer RB; configuring a Packet Data Convergence Protocol (PDCP) for each generated RB, and performing PDCP layer processing on SDAP Protocol Data Units (PDUs) on the RB according to requirements; uniformly configuring a group radio network temporary identifier G-RNTI/semi-persistent scheduling SPS G-RNTI for the service, and transmitting the service in a dynamic scheduling mode/semi-persistent scheduling mode in each cell for transmitting the service; uniformly configuring a C-RNTI/SPS C-RNTI for each RRC connection state UE receiving the service, wherein the C-RNTI/SPS C-RNTI is used for transmitting the service to the UE in a dynamic scheduling mode/semi-static scheduling mode in a cell where the UE is located, and K represents the number of generated RBs;

configuring an activated PTM bearer and an inactivated PTM bearer for the service in each cell for transmitting the service, configuring an activated PTP bearer or an inactivated PTP bearer for each RRC connected-state UE for receiving the service, configuring an activated DL BWP for each RRC connected-state UE for receiving the service, determining configuration information of each PTM bearer, determining configuration information of each PTP bearer, and determining DL BWP configuration information of each UE; each active PTM/PTP bearer is used for transmitting the service, and each inactive PTM/PTP bearer is in a standby state before being activated and is not used for transmitting the service;

2. The method according to claim 1, wherein the configuring active PTM bearers and inactive PTM bearers for the service, configuring one active PTP bearer or one inactive PTP bearer for each RRC connected UE receiving the service, and configuring active DL BWP for each RRC connected UE receiving the service comprises:

determining N configured for the MBS in each cell transmitting the MBS₁An active PTM bearer;

when N is present₁>0, when configuring each activated PTM bearer, selecting a BWP from the MBS dedicated BWPs configured in a unified manner for sending the PTM bearer, and configuring PTP bearers for RRC connected UEs that receive the PTM bearer on the selected BWP, where PTP bearers of each UE are sent on the selected BWP, and the PTP bearers configured for each UE are in an inactive state;

when N is present₁When the current configuration is 0, selecting at least one BWP from the MBS special BWPs which are configured uniformly for configuring PTP load to the RRC connection state UE which receives the service, and recording the selected BWP, wherein the PTP load configured for each UE is in an activated state;

in N₁>0, if at least one RRC connected UE receiving the service exists, and the UE cannot receive the service through any activated PTM bearer, excluding BWPs used for transmitting the activated PTM bearer in an MBS dedicated BWP configured in a unified manner, and selecting at least one BWP from the remaining BWPs for configuring PTP bearers for the UE, wherein PTP bearers configured for the UE are in an activated state;

number of BWPs N when recorded₃When not 0, configuring a PTM bearer for the service on each recorded BWP, wherein each configured PTM bearer is in an inactive state;

configuring activated DL BWP for each RRC connected UE receiving the service through PTM bearer or PTP bearer;

configuration information of each PTM bearer, configuration information of each PTP bearer, and DL BWP configuration information of each UE are determined.

3. The method according to claim 2, wherein the configuration information of the PTM bearer comprises basic configuration information of the PTM bearer and BWP configuration information of the PTM bearer;

wherein, the basic configuration information of the PTM bearer comprises: the MBS comprises a temporary mobile group identifier TMGI, a session identifier ID, a group radio network temporary identifier G-RNTI, a semi-persistent scheduling group radio network temporary identifier SPS G-RNTI, configuration information of an SDAP entity, configuration information of a PDCP entity, configuration information of an RLC entity and physical layer configuration information;

the BWP configuration information of the PTM bearer includes: sending basic parameters of BWP of the PTM bearer, sending configuration information of a control resource CORESET and a search space on the BWP of the PTM bearer and a discontinuous reception DRX mode of the PTM bearer;

the configuration information of the PTP bearer comprises basic configuration information of the PTP bearer and BWP configuration information of the PTP bearer;

wherein the basic configuration information of the PTP bearer includes: TMGI of the MBS, session ID, configuration information of the SDAP entity, configuration information of the PDCP entity, configuration information of the RLC entity, cell radio network identification C-RNTI of the UE, semi-persistent scheduling cell radio network identification SPS C-RNTI of the UE and physical layer configuration information;

the BWP configuration information of the PTP bearer includes: and sending the basic parameters of the BWP of the PTP bearer, sending configuration information of CORESET and a search space on the BWP of the PTP bearer and the DRX mode of the PTP bearer.

4. The method of claim 3,

in the same cell, each PTM bearer for transmitting the MBS service has the same basic configuration information and different BWP configuration information;

in different cells, PTM bearers configured for the MBS on the same MBS special BWP have the same basic configuration information and the same BWP configuration information except the DRX mode;

for a UE receiving a service, PTP bearers employed on the same MBS-dedicated BWP at different cells have the same basic configuration information and the same BWP configuration information except for DRX mode.

5. The method according to any of claims 1-4, wherein said configuring active PTM bearers and inactive PTM bearers for said service comprises:

configuring K RLC entities and K SC-MTCHs for the PTM bearer, wherein the K RLC entity is connected with the PDCP entity of the K RB of the service upwards and is connected with the K SC-MTCH downwards;

configuring K RLC entities and K DTCHs for PTP load bearing of each UE, wherein the kth RLC entity is connected with the PDCP entity of the kth RB of the service upwards and connected with the kth DTCH downwards;

when the kth RLC entity carried by the PTP and the kth RLC entity carried by the PTM on the same BWP adopt the same RLC mode, the kth RLC entity carried by the PTP and the kth RLC entity carried by the PTM have the same RLC parameters;

wherein, the RLC mode corresponding to the RLC entity carried by the PTM includes a TM mode or an UM mode; the RLC mode corresponding to the RLC entity of the PTP bearer includes a TM mode, an UM mode, or an AM mode.

6. The method of claim 5, wherein for a PTM bearer or a PTP bearer in an inactive state, K sets of RLC parameters and K SCs-MTCHs or DTCHs are configured; and the kth group of RLC parameters are used for configuring the kth RLC entity of the PTM bearer or the PTP bearer, and the kth SC-MTCH or DTCH corresponds to the PDCP entity of the kth RB.

7. The method of claim 5, wherein the RLC entities associated with the RB share a data storage area for storing PDCP PDUs from the PDCP entities of the RB and parameters employed by the respective RLC entities associated with the RB.

8. Method according to claim 6, wherein for inactive PTM or PTP bearers, N is configured₅The group RLC entities, wherein the kth RLC entity in each group of RLC entities is connected with the PDCP entity of the kth RB; wherein N is₅<N₄，N₄Indicating the number of PTM bearers in an inactive state and PTP bearers in an inactive state;

PTM/PTP bearing in inactive stateWhen the load is activated, from N₅Selecting a group of idle RLC entities from the group RLC entities, and configuring the idle RLC entities to the PTM/PTP bearer in the inactive state;

or configuring an RLC entity resource pool, wherein the RLC entity resource pool is composed of at least one RLC entity;

when the kth RB in the PTP bearer of one UE is activated, selecting an idle RLC entity from the RLC entity resource pool, configuring the idle RLC entity by using the kth group RLC parameters of the PTP bearer of the UE, connecting the idle RLC entity with the PDCP entity of the kth RB of the service, and connecting the RLC entity with the kth DTCH in the PTP bearer of the UE;

when an inactive PTM bearer is activated, K idle RLC entities are selected from the RLC entity resource pool for the PTM bearer, a K-th RLC entity is configured by using a K-th group of RLC parameters of the PTM bearer, the RLC entity is connected with a PDCP entity of a K-th RB of the service, and the RLC entity is connected with a K-th SC-MTCH of the bearer.

9. The method according to any of claims 1-4, wherein for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP on which the bearer is located, comprising:

for each activated PTM bearer, for each RRC connected state UE receiving the PTM bearer, transmitting configuration information of the PTM bearer, configuration information of a PTP bearer configured for the UE and configuration information of DL BWP configured for the UE to the UE through dedicated signaling;

determining a SET of beams SET for transmitting the PTM bearer;

splitting the PTM bearer into K₁+1 sub-PTM bearers, K₁The number of RBs which are periodically transmitted and have fixed data quantity transmitted each time in the RBs generated for the service is represented by P-RB, the RBs which are periodically transmitted and have fixed data quantity transmitted each time are represented by NP-RB, each P-RB has one sub PTM bearer for transmitting the P-RB to the UE in a PTM mode, the sub PTM bearers for representing the P-RB are represented by P-PTM bearers, and the rest sub PTM bearers are used for transmitting the data quantity to the PTM sideThe other (K-K) of the service₁) Transmitting RB to UE, using NP-PTM bearing to represent the sub PTM bearing, when K₁When the number of RBs is 0, each PTM bearer is split into unique sub PTM bearers, and the sub PTM bearers are used for transmitting all the RBs of the service to the UE in a PTM mode;

and on the BWP where the PTM bearer is positioned, the MAC layer allocates wireless resources for each sub PTM bearer of the PTM bearer and sends each sub PTM bearer through the allocated resources.

10. The method according to any of claims 1-4, wherein for each active PTM/PTP bearer, the MAC layer sends the bearer on the BWP on which the bearer is located, comprising:

for each activated PTP bearer, determining the UE using the PTP bearer, and sending the configuration information of the PTP bearer, the configuration information of the corresponding PTM bearer and the configuration information of DL BWP configured for the UE to the UE using the PTP bearer through dedicated signaling; the corresponding PTM bearer is used for transmitting the service, is in an inactive state, and is positioned on the same MBS special BWP with the PTP bearer;

and the MAC layer determines the BWP for transmitting the PTP bearer and transmits the PTP bearer on the corresponding BWP.

11. The method according to any of claims 1-4, wherein for each RRC connected UE receiving the service, the MAC layer dynamically switches the transmission mode of the service between PTM and PTP during the transmission of the service, comprising:

when the MAC layer determines that the service is transmitted through the PTP bearer of the UE, the PTP bearer is activated; when the MAC layer determines that one or more RBs of the service are transmitted through the PTP bearer of the UE, each RB which needs to be transmitted in a PTP mode in the PTP bearer of the UE is activated;

for each activated RB, an RLC entity associated with the RB in a PTP bearer of the UE determines a subscript of a first PDCP PDU to be transmitted, extracts the PDCP PDU from the data storage area from the PDCP PDU, executes corresponding processing, and transmits the generated RLC PDU to a MAC layer through a corresponding DTCH;

for the UE, if the transmission of each activated RB in the PTP bearer of the UE causes the parameter transmission change of the DRX mode configured to the UE by the MAC layer, the MAC layer sends an MAC CE in advance for transmitting a new DRX mode to the UE; after the new DRX mode takes effect, the MAC layer transmits each activated RB to the UE based on the new DRX mode;

in the process of transmitting the service through the PTP bearer, when the MAC layer determines to suspend transmitting part or all RBs through the PTP bearer, the part or all RBs enter an inactive state from an active state, and the MAC layer informs RLC entities corresponding to the part or all RBs;

each notified RLC entity inquires about INDEX stored in the corresponding data storage area and borne by the PTM in the storage area, and if the notified RLC entity finds that a plurality of PDCP PDUs before the PDCP PDU corresponding to the INDEX are not transmitted by the notified RLC entity, the notified RLC entity transmits the indication information of the slow speed to the MAC layer; then, the RLC entity continuously sends the PDCP PDU which is not transmitted to the MAC layer through the corresponding DTCH; after all the untransmitted PDCP PDUs are issued to the MAC layer, the RLC entity stops transmitting the RLC PDUs to the MAC layer through the DTCH; when no RLC entity is configured for the inactive PTM/PTP bearing, the state of the RLC entity becomes idle, and the connection of the RLC entity and the corresponding DTCH is disconnected;

and after receiving the indication information of the RLC entity with low speed, the MAC layer promotes the scheduling priority of the RB in the PTP bearer and preferentially schedules the radio resource for the RB.

12. The method according to any of claims 1-4, wherein for each RRC connected UE receiving the service, the MAC layer dynamically switches the transmission mode of the service between PTM and PTP during the transmission of the service, comprising:

for the BWP, whenever the number of RRC connected UEs receiving the service on the BWP increases or the location of the existing UEs receiving the service changes, the MAC layer determines whether to activate the PTM bearer in an inactive state configured for the service by the BWP; when the MAC layer determines to activate the PTM bearing, if the RLC entity is not configured for the PTM bearing, the MAC layer triggers the RLC layer to configure the RLC entity for the PTM bearing;

each RLC entity of the PTM load extracts the parameter INDEX stored in the data storage area of each activated PTP load from the corresponding data storage area, selects the PDCP PDU generated earliest from the PDCP PDUs indicated by each INDEX, extracts the PDCP PDU from the data storage area from the PDCP PDU for assembling the RLC PDU, and sends the assembled RLC PDU to the MAC layer through SC-MTCH;

the MAC layer receives the PTM to carry RLC PDUs transmitted through each SC-MTCH;

the MAC layer sends the PTM bearer on the BWP; before transmitting the PTM bearer, the MAC layer transmits MAC CE to each UE which receives the service through PTP bearer on the BWP;

in the process of transmitting the service through the PTM bearer, the MAC layer gradually stops transmitting the service to each UE through the PTP bearer; for the PTP bearer for stopping transmitting the service, the MAC layer triggers the PTP bearer to enter an inactive state; for each PTP bearer entering the inactive state, when no RLC entities are configured for the inactive PTM/PTP bearer, K RLC entities occupied by each PTP bearer stopping transmitting the service enter an idle state;

in the process of transmitting the service through PTM bearer, the MAC layer determines whether to activate part or all RBs in PTP bearer of UE; for each activated RB in the PTP bearer, the MAC layer transmits the RB through the PTP bearer;

in the process of transmitting the service through the PTM bearer, the MAC layer determines to send a beam set of the PTM bearer; when the number of beams included in the beam set for transmitting the PTM bearer is M₁When the value is 0, the MAC layer triggers the load to enter an inactive state; and when the RLC entities are not configured for the inactive bearer, the MAC layer also triggers K RLC entities occupied by the PTM bearer in the RLC layer to enter an idle state.

13. The method as claimed in any one of claims 1-4, wherein the transmitting the MBS to the UE through the corresponding bearer in the target cell through signaling interaction between the source cell and the target cell during the process that the UE moves from the source cell to the target cell comprises:

the source cell executes a first process when determining to execute cell switching according to the received measurement report of the UE, and sends an RRC switching request message to a target cell; wherein the RRC handover request message comprises: the configuration information of the service currently received by the UE, the C-RNTI and SPS C-RNTI of the UE and the configuration information of the common service; the configuration information of the service currently being received by the UE includes: TMGI, conversation ID, G-RNTI and SPS G-RNTI of the said business, ID of MBS special BWP where PTP bearing of UE locates, basic configuration information of PTP bearing of UE and basic configuration information of PTM bearing of the said business on BWP where PTP bearing of UE locates; the first processing comprises that if the PTP bearer of the UE is not activated, the RRC layer sends a message for activating the PTP bearer of the UE to the MAC layer of the cell, and the MAC layer activates the PTP bearer of the UE according to the message and transmits the service through the bearer;

after receiving the RRC switching request message, the target cell executes a second process and feeds back a switching request confirmation message to the source cell;

and the source cell sends RRC reconfiguration information to the UE according to the received switching request confirmation information so as to enable the UE to establish a corresponding bearer according to the RRC reconfiguration information and receive the service through the established bearer in the target cell.

14. The method according to claim 13, characterized in that when the target cell transmits said traffic over at least one active PTM bearer;

the executing the second processing and feeding back the handover request acknowledgement message to the source cell includes:

selecting one BWP from the BWPs in which each active PTM bearer is positioned, and configuring a PTP bearer for the UE on the selected BWP so as to perform PTM/PTP switching after the UE moves to the target cell;

the target cell saves the TMGI, the session ID, the G-RNTI, the SPS G-RNTI, the C-RNTI and the SPS C-RNTI in the RRC switching request message;

the target cell sends the handover request acknowledgement message to the source cell, wherein the handover request acknowledgement message includes: ID of MBS special BWP where PTP load of UE locates, PTM load activation indication, DRX mode of PTP load and DRX mode of PTM load and configuration information related to common service;

the source cell sends an RRC reconfiguration message to the UE according to the received handover request acknowledgement message, so that the UE establishes a corresponding bearer according to the RRC reconfiguration message, and receives the service through the established bearer in the target cell, including:

the source cell sends an RRC reconfiguration message to the UE according to the received switching request confirmation message, wherein the RRC reconfiguration message comprises: ID of MBS special BWP, PTP loading indication, PTM loading indication, configuration information of MBS special BWP, DRX mode of PTP loading, DRX mode of PTM loading and configuration information of common service; the UE refreshes the configuration information of the PTP/PTM bearer stored by the UE according to the DRX mode of the PTP/PTM bearer; when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; after the target cell is switched to, the UE receives the PTP bearer and the PTM bearer on the corresponding BWP according to the refreshed configuration information of the PTP/PTM bearer; and the UE continues to receive the common service after being switched to the target cell according to the configuration information related to the common service in the message.

15. The method according to claim 13, wherein when the target cell does not configure an active PTM bearer for the service and transmits the service only through an active PTP bearer, the performing the second process and feeding back a handover request confirm message to the source cell comprises:

the target cell determines the BWP in which each activated PTP bearer is located, selects a BWP from the BWPs, and if the ID of one BWP in the BWPs is the same as the ID of the BWP in the handover request, the target cell preferentially selects the BWP; the target cell configures PTP bearer for the UE on the selected BWP, so that the UE receives the service through the bearer after being switched to the target cell; if the UE has common service, configuring the common service of the UE on the MBS special BWP or a certain universal BWP of the BWP;

the target cell stores TMGI, session ID, G-RNTI, SPS G-RNTI, C-RNTI and SPS C-RNTI in the switching request;

the target cell sends a switching request confirmation message to the source cell, wherein the switching request confirmation message comprises: ID of MBS special BWP where PTP load of UE locates, DRX mode of PTP load and configuration information of common service;

the source cell sends an RRC reconfiguration message to the UE according to the received switching request confirmation message, wherein the RRC reconfiguration message comprises: ID of MBS special BWP, receiving PTP loading indication, configuration information of MBS special BWP, DRX mode of PTP loading and configuration information of common service;

the UE refreshes the configuration information of the PTP bearer stored by the UE according to the DRX mode of the PTP bearer in the switching request;

when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; and deleting the DRX mode of the PTM bearer from the refreshed configuration information of the PTM bearer;

after the target cell is switched to, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by the UE; and, prepare to receive PTM and bear the weight of in the target cell according to the configuration information that PTM that oneself refreshes bears the weight of;

and the UE continues to receive the common service after being switched to the target cell according to the configuration information of the common service in the message.

16. The method of claim 13, wherein when the target cell is not transmitting the traffic,

selecting a BWP from MBS special BWP, configuring activated PTP load for UE on the BWP, and configuring non-activated PTM load for the service; when the PTP bearer is configured for the UE, the basic configuration information of the PTP bearer in the switching request is used as the basic configuration information of the PTP bearer configured for the UE; when configuring PTM load bearing for the service, using the PTM load bearing basic configuration information in the switching request as the basic configuration information of the PTM load bearing; determining the configuration information of the BWP in the configuration information of the PTP/PTM bearer according to the configuration information of the selected BWP; if the UE has common service, configuring the common service of the UE on the MBS special BWP or a certain universal BWP of the BWP;

the target cell determines the session of the MBS needing 5GC transmission according to the TMGI and the session ID of the MBS in the switching request, and triggers the 5GC to transmit the control plane information and the user plane data of the service to the target cell through a control plane interface and a user plane interface respectively by a control plane interface between the target cell and the 5 GC;

the target cell sends a handover request acknowledgement message to the source cell, wherein the handover request acknowledgement message includes: ID of MBS special BWP where PTP load of UE locates, DRX mode of PTP load and configuration information of common service;

the UE refreshes the configuration information of the PTP bearer stored by the UE according to the DRX mode of the PTP bearer in the message;

when the ID of the MBS special BWP in the message is different from the ID of the BWP of the MBS received by the UE in the source cell, the UE refreshes the BWP configuration information in the configuration information of the PTP/PTM bearer stored by the UE according to the configuration information of the MBS special BWP in the message; deleting the DRX mode of the PTM bearer in the refreshed configuration information of the PTM bearer;

after the target cell is switched to, the UE receives the PTP bearer on the corresponding BWP according to the configuration information of the PTP bearer refreshed by the UE; and the UE prepares to receive the PTM bearer in the target cell according to the configuration information of the self-refreshed PTM bearer;

17. The method of claim 13, wherein during the process of moving the UE from the source cell to the target cell, the MBS is transmitted to the UE through a corresponding bearer in the target cell through signaling interaction between the source cell and the target cell, and the method comprises:

when a target cell receives a switching request sent by a source cell, for an MBS being received by UE, if the target cell transmits the service by PTM bearing and/or PTP bearing, for each RB of the MBS, only newly generated PDCP PDU is placed in a data storage region of the RB from the current moment; determining SN of PDCP PDU generated earliest in storage area of kth RB by TSN_kRepresents the SN; transmitting K SNs to a source cell through a handover request acknowledgement message, the K SNs being: TSN_k，k＝1,……,K；

After receiving the switching request confirmation message, the source cell determines, for the UE in the switching process, a parameter INDEX stored in a storage area of a kth RLC entity in a PTP bearer of the UE in the kth RB; by SSN_kSN indicating PDCP PDU to be extracted next by the kth RLC entity;

if SSN_kCorresponding PDCP PDU generation time is earlier than TSN_kCorresponding PDCP PDU shows that the transmission speed of the PDCP PDU of the kth RB in the PTP load of the UE in the source cell is later than that of the same RB in the target cell, and STSN is used_kDenotes SN as TSN_kThe source cell is SSN from SN in the storage area corresponding to the kth RB_kThe PDCP PDUs start to extract each PDCP PDU until the SN is extracted as STSN_kPDCP PDU of (1); forwarding the extracted PDCP PDUs to a target cell;

if SSN_kCorresponding PDCP PDU generation time later than TSN_kWhen the UE is in the source cell, the transmission speed of the PDCP PDU of the kth RB in the PTP bearer of the UE in the source cell is higher than that of the same RB in the target cell, and the corresponding PDCP PDU is not required to be forwarded for lossless reception of the kth RB in the source cell;

for the forwarded PDCP PDUs of the kth RB, in the target cell, the kth RLC entity in the PTP bearer of the UE preferentially transmits the forwarded PDCP PDUs to the MAC layer, so that the MAC layer preferentially transmits the forwarded PDCP PDUs; after the transmission of the forwarded PDCP PDU is finished, the RLC entity starts to transmit the PDCP PDU in the corresponding data storage area;

or, when the target cell receives the handover request sent by the source cell, for the MBS being received by the UE, if the target cell does not transmit the service, the target cell carries the nondata in the handover request message, where the nondata is 0 and is used to indicate that the target cell has not transmitted the MBS;

after receiving the switching request confirmation message, when the NoData in the message is 0, for the UE in the switching process, the source cell determines the parameter INDEX stored in the storage area of the k-th RB by the k-th RLC entity in the PTP bearer of the UE, and uses SSN_kSN indicating PDCP PDU to be extracted next by the kth RLC entity;

for each RB in the PTP bearer of the UE, the source cell forwards PDCP PDUs stored in a data storage area of the RB to the target cell in sequence from the next PDCP PDU to be extracted, and when a new PDCP PDU is put into the storage area, all the newly put PDCP PDUs also need to be forwarded to the target cell in sequence;

the target cell receives PDCP PDUs of all RBs forwarded by the source cell; after the target cell starts to receive the MBS conversation of the service from the 5GC, the target cell determines the SN of the first PDCP PDU of each RB in the received MBS conversation; representing the SN before the SN as STOPSN; if the PDCP PDU received from the source cell and forwarded by the RB comprises the PDCP PDU with the SN of STOPSN, the target cell does not need the source cell to forward the PDCP PDU of the RB; otherwise, the target cell forwards the PDCP PDU of the RB to the source cell until the PDCP PDU with the SN of STOPSN is forwarded to the target cell; the target cell generates a STOP indication message according to the generated STOP indication message, wherein the STOP indication message carries a parameter STOP, and when the STOP is 1, the target cell indicates that the source cell STOPs forwarding the PDCP PDU; when the STOP is 0, carrying an RB list in the message, for instructing the source cell to forward only PDCP PDUs of each RB in the RB list;

when receiving a STOP indication message from the target cell, if STOP in the message is 1, the source cell STOPs forwarding PDCP PDUs of each RB of the service;

if STOP in the message is 0, the source cell extracts the carried K in the message₂For each group of parameters in the list, the source cell determines the RB which needs to continuously forward the PDCP PDU according to the RB subscript in the group of parameters; determining the SN of the last PDCP PDU which needs to be forwarded in the PDCP PDUs of the RB according to the STOPSN in the set of parameters;

and for each RB to be forwarded, the source cell continues to forward the PDCP PDU from the storage area of the RB until the PDCP PDU with the SN of STOPSN is completely forwarded.

18. The method according to any one of claims 1-4, further comprising:

determining one base station from a plurality of interconnected base stations as a main node, and determining base stations except the main node as auxiliary nodes;

wherein, the unified configuration and corresponding configuration result across the gNB executed by the master node includes:

the primary node transmits the configuration information of each MBS special BWP, the configuration information of each general BWP of each MBS special BWP and the basic configuration information borne by the PTM of one MBS to the secondary node, wherein the basic configuration information borne by the PTM of one MBS comprises TMGI, session ID, G-RNTI, SPS G-RNTI, SDAP configuration information, PDCP configuration information, RLC configuration information, PDSCH configuration information and PDCCH configuration information.

19. A transmission system of multicast broadcast service in an NR cell is characterized by comprising a plurality of interconnected base stations, wherein one base station is used as a main node, and base stations except the main node are used as auxiliary nodes;