CN116686310A - Method for cell switching or reselecting in MBS service - Google Patents

Abstract

The application provides a method for carrying out cell switching or reselection in MBS service, which is executed at a user equipment side and comprises the following steps: acquiring a user service description, wherein the user service description comprises a temporary mobile group identifier, MBS session service and a first service area identifier of a cell, and the first service area identifier corresponds to the temporary mobile group identifier and the session service; receiving a system information block of a broadcast control channel, wherein the system information block comprises second service area identifiers of a plurality of adjacent cells; and selecting to switch or reselect to a corresponding adjacent cell containing the first service area identification in the second service area identification. Through the method for carrying out cell switching or reselection based on cell priority, the UE is ensured not to interrupt receiving MBS service.

Description

Method for cell switching or reselecting in MBS service [ field of technology ]

The disclosed embodiments of the present application relate to the MBS communication technology field, and more particularly, to a method and a user equipment for performing cell handover or reselection in an MBS service.

[ background Art ]

The transmission modes of the multimedia broadcast Multicast service (Multimedia Broadcast Multicast Service, MBMS) of LTE can be classified into SC-PTM (Single Cell Point-To-Multipoint) and MBSFN (Multicast/Multicast single frequency network). The UE receives the MSMS service through the SC-PTM transmission mode, and when the cell selection or the cell reselection is required, the UE performs the following mode to ensure that the MBMS service is not interrupted to be transmitted: (1) and receiving a broadcast control channel SIB15, wherein the SIB15 comprises SAI (MBMS Service Area Identities) of the cell and the neighbor cell, and if the UE finds that the neighbor cell does not have SAI required by the UE, when the UE is in an idle state to perform cell reselection, the UE may preferentially select the cell corresponding to the MBMS service of interest. When the UE is in a connected state for handover, a notification may be sent to let the target handover cell set up the MSMS service in advance so that the service does not interrupt transmission. (2) Each MBMS service supported by the cell, the SC-MCCH (Single Cell MBMS Control Channel, single-cell MBMS control channel) informs the UE which neighbor cells can also support the same MBMS service, so that the UE can request to continue transmitting the MBMS service by unicast if performing cell switching or reselecting to a cell that does not support the MBMS service. (3) The UE in the connected state can also notify the network side of the MBMS service of interest, so that the network side sets up in advance to meet the mobility requirements of the broadcast multicast service and the unicast service of the UE.

However, in the MBS (Multicast Broadcast Service ) in the current 5G new air interface network, there are two transmission modes, namely PTM (Point to Multipoint, point-to-multipoint transmission) and PTP (Point-to-Point transmission), instead of the MBSFN transmission mode of MBMS in the LTE network. And the MBS service needs to support the V2X service with high requirements on time delay and reliability. Due to the different transmission modes and the different supported services, the mode of cell handover or cell reselection by the UE may also be different in MBS services in the NR network.

Therefore, a standard needs to be proposed to define a method for performing cell handover or cell reselection by the UE in MBS service.

[ application ]

According to the embodiment of the application, the application provides a method for carrying out cell switching or reselection in MBS service to solve the technical problems.

According to a first aspect of the present application, there is provided a method for performing cell handover or reselection in an MBS service, the method being performed at a user equipment side, the method comprising: acquiring a user service description, wherein the user service description comprises a temporary mobile group identifier, MBS session service and a first service area identifier of a cell, and the first service area identifier corresponds to the temporary mobile group identifier and the session service; receiving a system information block containing second service area identifiers of a plurality of adjacent cells, and reading the second service area identifiers of the plurality of adjacent cells; and selecting to switch or reselect to a corresponding adjacent cell containing the first service area identification in the second service area identification.

According to a second aspect of the present application there is provided a user equipment comprising a processor and communication circuitry, the processor being connected to the communication circuitry, the processor being for performing the method as in the first aspect.

According to a third aspect of the present application there is provided a user equipment having stored instructions which when executed implement a method as in the first aspect.

The beneficial effects of the application are as follows: the application obtains the user service description through UE, the user service description comprises the temporary mobile group identification, MBS session service and the first service area identification of the cell, thereby obtaining the first service area identification and the temporary mobile group identification corresponding to the MBS service required by the user; and then, through receiving the system information block containing the second service area identifiers of the plurality of adjacent cells, switching or reselecting to the corresponding adjacent cell containing the first service area identifier in the second service area identifier so as to continuously receive the required MBS service, thereby ensuring uninterrupted transmission of the MBS service required by the UE.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

fig. 1 is a schematic diagram of information elements of a system information block 15 in MBMS;

fig. 2 is a flow chart of an embodiment of a method of cell handover or reselection in accordance with the present application;

fig. 3 is a schematic structural diagram of a ue according to an embodiment of a cell handover or reselection-based method of the present application;

fig. 4 is a storage schematic diagram of a user equipment according to an embodiment of the method of the present application based on cell handover or reselection.

[ detailed description ] of the application

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In the conventional SC-PTM transmission mode of the MBMS service, the user service description (User Service Description, USD) includes a temporary mobile group identifier (Temporary Mobile Group Identity, TMGI), a service session (session), a carrier Frequency point (Frequency, F), and a service area identifier (Service Area Identities, SAI), that is, usd=tmgi+session+f (Frequency point) +sai, that is, the MBMS service carried on the same carrier Frequency point is the same, that is, the carrier Frequency point and the TMGI are corresponding, and the same carrier Frequency point may correspond to a plurality of SAIs, and there may be at most 64 SAIs on a Frequency band where one carrier Frequency point is located.

In the MBMS service, the UE performs cell handover or reselection preferentially based on frequency to ensure continuous transmission of the service. The specific flow is as follows: the UE acquires the USD at the application layer, and based on the USD, the UE can acquire carrier frequency F corresponding to the SAI and TMGI of the MBMS service. The UE receives SIB15 (system information block 15) sent by the broadcast control channel, where an information element of SIB15 is shown in fig. 1, where an information element MBMS-SAI-IntraFreq-r11 carries carrier frequency related to the MBMS service of the cell and a corresponding SAI, and an information element MBMS-SAI-intersfreqlist-r 11 carries other carrier frequency related to the MBMS service of the neighboring cell and a corresponding SAI, and when the UE performs cell reselection or handover or reselection, the UE can preferentially select a cell of the MBMS service required by itself.

Specifically, the following examples can be used for illustration. For example, the UE obtains the USD through the application layer, the contents of which are shown in table 1.

TABLE 1

SAI	Carrier frequency point	TMGI	Session services
1	F1	TMGI1	Session1
2	F1	TMGI1	Session2
3	F1	TMGI2	Session1
…	…	…	…
63	F1	TMGI62	Session1
64	F1	TMGI63	Session1
65	F2	TMGI65	Session1

66

F2

TMGI66

Session1

As can be seen from table 1, F1 in the USD contains 64 SAIs, which corresponds to 63 TMGIs and 64 sessions, and F2 contains 2 SAIs, which corresponds to 2 TMGIs and 2 sessions.

The UE acquires SAI of 5 neighbor cells by receiving SIB15 of the broadcast control channel, as shown in table 2.

TABLE 2

SAI	Carrier frequency point	Neighboring cell code
3	F1	Cell 1
3,4	F1	Cell 2
5	F1	Cell 3
65	F2	Cell 4
66	F2	Cell 5

Assuming that the UE is interested in the traffic of TMGI2 (corresponding to sai=3), it can be known from table 1 that the traffic is carried on carrier frequency point F1, when the UE performs cell reselection or cell switching, the UE preferentially searches for the corresponding cell in the neighboring cell according to carrier frequency point F1, and does not consider whether other frequency points such as F2 of the neighboring cell carry the traffic at all. Further, by searching for that all of the cell 1, the cell 2 and the cell 3 contain the carrier frequency point F1, and then providing the service only in the cell 1 and the cell 2 according to the SAI of 3, the UE will select between the cell 1 and the cell 2, but will not select the cell 3.

Of course, in an embodiment, when the TMGI and the carrier frequency point of the MBS service are corresponding to each other in a binding manner, the MBS service may also use the above method for performing cell handover or reselection based on frequency priority to ensure continuous transmission of the MBS service. However, in the existing new air interface network, the TMGI and the carrier frequency point F may not be corresponding to each other in a binding manner, and different carrier frequency points may exist to carry the same MBS session service.

In another embodiment, the present application provides a method for performing cell switching or reselection in MBS service, which is performed at a UE side, and is based on cell switching or reselection preferentially to ensure continuous transmission of MBS service, referring to fig. 2, fig. 2 is a flow chart of an embodiment of the method for cell switching or reselection of the present application, and specifically includes the following steps:

s110, obtaining user service description, wherein the user service description comprises a temporary mobile group identifier, MBS session service and a first service area identifier of a cell, and the first service area identifier corresponds to the temporary mobile group identifier and the session service.

In order to receive MBS service on the MBS service control channel, the UE generally completes a service announcement procedure in which USD is received, where the UE may acquire USD information by broadcasting or may acquire USD information of the MBS service by non-broadcasting (e.g. unicast, email, etc.), and the method of acquiring USD information by the UE is not limited in the present application. The USD information generally includes a first Service Area Identity (SAI), a Temporary Mobile Group Identity (TMGI), and an MBS session service (session) within the home cell of the MBS service of interest to the UE. In this embodiment, the first SAI further includes a Mobile Country Code (MCC), a Mobile Network Code (MNC), a Location Area Code (LAC), and a Service Area Code (SAC). The TMGI includes MCC, MNC and MBS service ID. The MBS session also includes a start time (start), a duration (duration), etc. of the MBS service. Therefore, in one USD, the first SAI and the TMGI and session are corresponding, and after the UE reads the USD, the UE can know which TMGI the first SAI corresponds to (i.e. corresponds to the MBS service).

And S120, receiving a system information block of the broadcast control channel, wherein the system information block comprises second service area identifiers of a plurality of adjacent cells.

The UE may receive a system information block through a broadcast control channel, where the system information block includes second SAIs of MBS services continuously transmitted by a plurality of neighboring cells in a current period, and the number of the second SAIs may be plural, and may learn whether there are SAIs of interest in the second SAIs by reading the plurality of second SAIs of the plurality of neighboring cells.

S130, selecting to switch to or reselect to a corresponding adjacent cell containing the first service area identification in the second service area identification.

The UE is interested in the session service of the TMGI corresponding to the first SAI, and can select to switch to or reselect to the cell by comparing whether the cell of the first SAI exists in the second SAI of the plurality of read neighbor cells. Of course, the second SAI also includes a Mobile Country Code (MCC), a Mobile Network Code (MNC), a Location Area Code (LAC), and a Service Area Code (SAC).

Specifically, the examples described above are continued. For example, the UE obtains a USD, the contents of which are shown in table 3.

TABLE 3 Table 3

SAI	TMGI	Session services
1	TMGI1	Session1
2	TMGI1	Session2
3	TMGI2	Session1
…	…	…
63	TMGI62	Session1
64	TMGI63	Session1

65	TMGI65	Session1
66	TMGI66	Session1

As can be seen from table 3, in the USD, the SAI corresponds to the TMGI and session only, and is not mandatory to limit the MBS service carrying the TMGI on which carrier frequency points. Suppose that the MBS service of interest to the UE is TMGI2, corresponding to sai=3.

The UE acquires SAI of other 5 neighbor cells by receiving the system information block of the broadcast control channel, as shown in table 4.

TABLE 4 Table 4

SAI	Carrier frequency point	Neighboring cell code
3	F1	Cell 1
65	F1	Cell 2
5	F1	Cell 3
3	F2	Cell 4
66	F2	Cell 5

The UE is interested in the MBS service with sai=3, and it can be known from table 4 that both cell 1 and cell 4 can provide the service, and the UE will select a cell from cell 1 and cell 4, without considering whether the service is carried at carrier frequency point F1 or carrier frequency point F2. It will be appreciated that in a method for cell handover or reselection based on cell preference, the carrier frequency point is not the first choice but the neighbor cell containing the SAI is directly selected for handover or reselection based on the SAI of interest.

As described above, when the second SAI selects to switch to or reselect to the corresponding neighboring cell including the first SAI, the UE selects the final cell to switch to or reselect to the target neighboring cell according to the conventional cell selection method, the random selection method, or the UE implementation method. And when the connected UE is switched to the target neighbor cell containing the first SAI, sending a notification for establishing the MBS service to the target neighbor cell so as to establish the MBS service in advance, thereby ensuring uninterrupted transmission of the MBS service. And when the UE in the inactive state or idle state performs cell reselection, the UE can preferentially select the interested cell as the target neighbor cell.

In another embodiment, the USD information may further include a carrier frequency point, where MBS services of the same TMGI are carried in the same carrier frequency point, or MBS services of the same TMGI may be carried in different carrier frequency points. When the same MBS service is carried by different carrier frequency points, the first SAI can be set the same or set different, wherein the SAI of the frequency band where the carrier frequency point is located is less than or equal to 64.

Specifically, the description may be continued by the above examples. For example, the UE obtains a USD, the contents of which are shown in table 5.

TABLE 5

SAI	Carrier frequency point	TMGI	Session services
1	F1	TMGI1	Session1
2	F1	TMGI1	Session2
3	F1	TMGI2	Session1
…	…	…	…
63	F1	TMGI62	Session1
64	F1	TMGI63	Session1
3 or 65	F2	TMGI2	Session1
66	F2	TMGI66	Session1
67	F3	TMGI67	Session1
68	F3	TMGI68	Session1

As can be seen from table 5, F1 in the USD contains 64 SAIs, which corresponds to 63 TMGIs and 64 sessions, and F2 contains 2 SAIs, which corresponds to 2 TMGIs and 2 sessions. However, F2 also includes MBS service of TMGI2, and the corresponding SAI may be the same as that in F1, with sai=3, or may be different from that in F1, with sai=65. That is, when different carrier frequency points bear the same MBS service, the SAI may be set the same or set different.

The UE acquires SAI of other 6 neighbor cells by receiving the system information block of the broadcast control channel, as shown in table 6.

TABLE 6

SAI	Carrier frequency point	Neighboring cell code
3	F1	Cell 1
64	F1	Cell 2
5	F1	Cell 3
3	F2	Cell 4
66	F2	Cell 5
67	F3	Cell 6

Assuming that the UE is interested in TMGI2, it can be known from table 5 that the corresponding first sai=3 or first sai=65, and the carrier frequency carrying the MBS service is F1 or F2, so when the second SAI of the neighboring cell is acquired to perform cell handover or reselection, the cell containing the carrier frequency F1 or F2 is considered first, but the cell containing the carrier frequency F3 is not considered. From table 5, the UE prioritizes 5 cells (cell 1, cell 2, cell 3, cell 4 and cell 5) containing F1 and F2, and then searches for a cell containing the first SAI from these 5 cells, namely cell 1 and cell 4, among which the UE will select, although the handover or reselection of the final target neighbor cell may be performed according to conventional cell selection, random selection or according to the UE implementation. It can be appreciated that in this embodiment, the UE is a method for performing cell handover or reselection based on both carrier frequency and cell consideration.

In summary, in the MBS service in the NR network, the UE may perform cell switching or reselection based on frequency preference, may perform cell switching or reselection based on cell preference, or may perform cell switching or reselection based on frequency and cell consideration at the same time.

Referring to fig. 3, fig. 3 is a schematic structural diagram of an embodiment of a ue according to the present application. The present user equipment 10 comprises a processor 12 and a communication circuit 11; the processor 12 is connected to the communication circuit 11, and the processor 12 is configured to execute instructions to implement the above-described cell handover or reselection method.

The processor 12 may also be referred to as a CPU (Central Processing Unit ). The processor 12 may be an integrated circuit chip having signal processing capabilities. Processor 12 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor 12 may be any conventional processor or the like.

Referring to fig. 4, fig. 4 is a schematic diagram of a storage structure of a ue in an embodiment of the present application. The user equipment 20 of the embodiment of the present application stores instruction/program data 21 which, when executed, implements the method provided by any embodiment of the cell handover or reselection method of the present application, as well as any non-conflicting combination. The instructions/program data 21 may form a program file stored in the storage medium of the user device 20 as a software product, so that a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) performs all or part of the steps of the methods according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, an optical disk, or other various media capable of storing program codes, or a terminal device such as a computer, a server, a mobile phone, a tablet, or the like.

In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of elements is merely a logical functional division, and there may be additional divisions of actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The foregoing is only the embodiments of the present application, and therefore, the patent scope of the application is not limited thereto, and all equivalent structures or equivalent processes using the descriptions of the present application and the accompanying drawings, or direct or indirect application in other related technical fields, are included in the scope of the application.

Claims (10)

1. A method for performing cell handover or reselection in MBS service, the method being performed at a user equipment side, the method comprising:

   acquiring a user service description, wherein the user service description comprises a temporary mobile group identifier, MBS session service and a first service area identifier of a cell, and the first service area identifier corresponds to the temporary mobile group identifier and the session service;

   receiving a system information block of a broadcast control channel, wherein the system information block comprises second service area identifiers of a plurality of adjacent cells;

   and selecting to switch or reselect to a corresponding adjacent cell containing the first service area identification in the second service area identification.
2. The method of claim 1, wherein the first service area identification and the second service area identification comprise a mobile country code, a mobile network code, a location area code, and a service area code.
3. The method of claim 2, wherein the user service description further comprises carrier frequency points;
4. the method of claim 3, wherein the first service area identifier is set identically or set differently when different carrier frequency points carry the same MBS session service.
5. The method of claim 4, wherein selecting to switch or reselect in the second service area identity to a corresponding neighbor cell that contains the first service area identity further comprises:

   selecting a corresponding carrier frequency point carrying the MBS session service in a second service area identifier according to the MBS session service;

   and selecting and switching to or reselecting to a corresponding adjacent cell containing the first service area identifier according to the carrier frequency point.
6. The method of claim 4, wherein the frequency band in which the carrier frequency point is located includes less than or equal to 64 service area identifiers.
7. The method of claim 1, wherein the selecting to switch to or reselect to the corresponding neighbor cell containing the first service area identity in the second service area identity further comprises:

   when the number of the corresponding neighbor cells containing the first service area identification is multiple, the UE switches or reselects to the target neighbor cell according to a traditional cell selection method, a random selection method or a UE implementation condition method.
8. The method of claim 7, wherein switching to the target neighbor cell further comprises:

   and the UE in the connection state is switched to the target adjacent cell, and a notification of establishing MBS service is sent to the target adjacent cell so as to establish the MBS service in advance.
9. A user device comprising a processor and a communication circuit, the processor being coupled to the communication circuit;

   the processor is configured to perform the method of any of the preceding claims 1-8.
10. A user equipment storing instructions which when executed implement the method of any of claims 1-8.