Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus, the method comprising: receiving first information from a first network device, wherein a first cell belongs to the first network device, the first cell is a serving cell currently accessed by a terminal device, the first information comprises a first field, and the first field is used for indicating a candidate cell or indicating a candidate cell and the serving cell currently accessed by the terminal device; and determining the first cell or a second cell on the basis of the first information and a first rule, wherein the second cell is a candidate cell, and the first rule is used for indicating a correspondence between the first field and the candidate cell, or a correspondence between the first field and the candidate cell and a correspondence between the first field and the serving cell currently accessed by the terminal device. According to the communication method and the communication apparatus of the present application, when the terminal device accesses the first cell, the candidate cell or the serving cell for which timing advance needs to be obtained is determined on the basis of a clear indication of a field in the first information, so as to prepare for flexible handover of the terminal device among a plurality of cells.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 28, 2023, with application number 202311290105.0 and invention name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and more specifically, to a communication method and a communication device. Background Art

[0003] In mobile communication systems, terminal devices can switch between different cells under the control of network equipment. Currently, network equipment can instruct terminal devices to initiate random access requests to neighboring cells based on downlink control signaling. Therefore, whether terminal devices can efficiently and flexibly switch between cells depends on clear instructions from network equipment.

[0004] Therefore, how to clearly instruct a terminal device to switch to a corresponding cell so as to enable the terminal device to switch flexibly and efficiently between multiple cells is a problem that needs to be solved urgently.

[0005] Summary of the Invention

[0006] The present application provides a communication method and a communication apparatus, in which a terminal device can implement flexible switching between multiple cells through explicit instructions from a network device.

[0007] In a first aspect, a communication method is provided, including: receiving first information from a first network device, a first cell belonging to the first network device, the first cell being a service cell currently accessed by a terminal device, the first information including a first field, the first field being used to indicate a candidate cell, or the first field being used to indicate the candidate cell and the service cell currently accessed by the terminal device; determining the first cell or the second cell according to the first information and a first rule, the second cell belonging to the candidate cell, the second cell belonging to the first network device, or the second cell belonging to the second network device, wherein the first rule is used to indicate a correspondence between the first field and the candidate cell; or the first rule is used to indicate a correspondence between the first field and the candidate cell and a correspondence between the first field and the service cell currently accessed by the terminal device.

[0008] Exemplarily, the first information may be downlink control indication (DCI) signaling sent by the first network device to the terminal device via a physical downlink control channel (PDCCH), where the DCI includes a field for indicating the candidate cell. For example, the field may be a "cell indicator" field.

[0009] The first rule may be replaced by "correspondence", "association", etc. The first rule may also be used to indicate the correspondence between the value of the first field and the identifier of the candidate cell; the first rule may also be used to indicate the correspondence between the value of the first field and the physical identifier of the candidate cell; the first rule may also be used to indicate the correspondence between the value of the first field and the logical identifier of the candidate cell, etc.

[0010] It should be understood that when the first rule is used to indicate the correspondence between the first field and the candidate cell, the terminal device can determine the second cell based on the first information and the first rule; when the first rule is used to indicate the correspondence between the first field and the candidate cell and the relationship between the first field and the service cell currently accessed by the terminal device, the terminal device can determine the first cell and / or the second cell based on the first information and the first rule.

[0011] It should be noted that the first rule can be used to indicate the correspondence between the first field and the cell. The cell may include a candidate cell, or may include a candidate cell and a service cell currently accessed by the terminal device. As the terminal device switches, the service cell currently accessed by the terminal device may also change. The cell accessed by the terminal device before the switch can be understood as the service cell currently accessed by the terminal device, and the cell accessed by the terminal device after the switch can be understood as the service cell after the terminal device switches. When the terminal device switches, the service cell after the terminal device switches can also be understood as the service cell currently accessed by the terminal device. The "current" and the "current" before the switch may not be the same moment.

[0012] It should be understood that when the second cell belongs to the first network device, it corresponds to the scenario in which the terminal device within the first network device switches between cells; when the second cell belongs to the second network device, it corresponds to the scenario in which the terminal device between multiple network devices switches between cells.

[0013] Based on the above scheme, when the terminal device accesses the first cell, it can determine the candidate cell or service cell for which timing advance needs to be obtained based on the first information from the first network device of the first cell and the clear indication of the field in the first information, thereby preparing for the flexible switching of the terminal device between multiple cells.

[0014] In combination with the first aspect, in some implementations of the first aspect, the method further includes: sending a random access request message 1 (preamble) to the first cell or the second cell according to the first information and the first rule.

[0015] Based on the above solution, the terminal device can determine to send a random access request message 1 (preamble code) to a candidate cell under the clear instruction of the first information and in accordance with the first rule, so that the network device can obtain the timing advance of the terminal device in the corresponding cell.

[0016] In combination with the first aspect, in certain implementations of the first aspect, the first cell is a cell configured with random access resource configuration, and the first rule includes: the first field of the first value corresponds to the first cell, and the first fields of other values ​​correspond to different candidate cells; the first information includes the first field of the second value.

[0017] Exemplarily, the random access resource configuration may be a layer 1, layer 2 triggered mobility (L1 / L2 triggered mobility, LTM) random access resource configuration. The first cell is a cell configured with random access resources. It can be understood that the first cell may also be used as a candidate cell for the terminal device. After the terminal device switches from the first cell to another cell, the terminal device may also switch back to the first cell from the other cell.

[0018] It should be understood that the first fields of other values ​​correspond to different candidate cells in a one-to-one correspondence. The terminal device can initiate random access to different candidate cells based on the first fields of other values ​​and the first rule. The candidate cell configuration may include the configuration of the service cell currently accessed by the terminal device, and the corresponding random access resources. That is, when the value of the first field indicates that the terminal device initiates a random access request to the candidate cell, since the candidate cell configuration includes the configuration of the service cell currently accessed by the terminal device, it can also trigger the terminal device to initiate access to the currently accessed service cell. When the first field of the first value (for example, the minimum value of the first field) corresponds to the service cell currently accessed by the terminal device, in addition to the first field of the first value, the first field of other values ​​may also trigger the terminal device to initiate a random access request to the currently accessed service cell.

[0019] It is understandable that the first information may also include a first field with other values, which is not limited in this application.

[0020] Based on the above solution, the terminal device can determine the candidate cell to be switched to based on the different values ​​of the first field, thereby being able to initiate random access to different candidate cells. In addition, because the serving cell currently accessed by the terminal device is also configured with random access resource configuration, the terminal device can switch back to the original serving cell after switching from the currently accessed serving cell to a candidate cell, thereby achieving flexible switching of the terminal device between different cells.

[0021] In combination with the first aspect, in certain implementations of the first aspect, initiating random access to the first cell or the second cell based on the first information and the first rule includes: sending a random access request message 1 to the first cell based on the first field of the first value and the first rule.

[0022] In combination with the first aspect, in certain implementations of the first aspect, random access is initiated to the first cell or the second cell based on the first information and the first rule, including: sending a random access request message 1 to different candidate cells based on the first field of the other value and the first rule.

[0023] Based on the above scheme, when the first field of the first value in the first rule corresponds to the first cell and the first field of the second value corresponds to the second cell, the terminal device can determine the candidate cell to be switched based on the first fields with different values, and send a random access request message 1 to the candidate cell to be switched.

[0024] In combination with the first aspect, in certain implementations of the first aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched, and the first rule is: the first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; wherein, the first rule is determined according to the order of the candidate cells configured with random access resource configurations.

[0025] It should be understood that the candidate cell configured with random access resources can be understood as the candidate cell's random access resource configuration existing in the LTM candidate cell random access resource configuration. The first cell accessed by the terminal device before handover is also configured with random access resources, and the random access resource configuration of the first cell also exists in the LTM candidate cell random access resource configuration.

[0026] Exemplarily, the order of candidate cells configured with random access resources before and after the terminal device is switched is fixed, and therefore, the correspondence between different values ​​and candidate cells in the first rule is fixed. For example, a first field with a value of '00' corresponds to cell 1 before and after the switch, and a first field with a value of '01' corresponds to cell 2 before and after the switch.

[0027] It should be noted that before switching to the second cell, the terminal device is connected to the first network device of the first cell. Among them, the first cell is a cell configured with random access resource configuration, which can be understood as the random access resource configuration of the first cell also belonging to the random access resource configuration of the candidate cell. For example, the random access channel (RACH) resources of the first cell exist in the LTM configuration. At this time, the value of the DCI field can be mapped according to the order of the list of candidate cells containing RACH resources in the LTM configuration (the logical identifier of the candidate cells configured with random access resources is in ascending order), that is, the correspondence between the first field and the candidate cell is mapped. Among them, the relationship between the first field and the candidate cell can also be understood as the correspondence between the value of the first field and the candidate cell.

[0028] Exemplarily, when the correspondence between the value of the first field and the candidate cells is mapped according to the order of the candidate cells containing RACH resources in the LTM configuration, during the switching of the terminal device between cells, the value of the first field corresponds to the candidate cell one-to-one, and the correspondence does not change with the switching of the terminal device. Unless the radio resource control (RRC) reconfigures the candidate cell list of the LTM. Among them, the one-to-one correspondence between the value of the first field and the candidate cell can be understood as the one-to-one correspondence between the value of the first field and the physical cell identity (PCI) of the candidate cell.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the first field of the second value corresponds to the second cell, wherein the fourth value is a minimum value.

[0030] It should be understood that after the terminal device switches from the first cell to the second cell, the second cell is the service cell after the terminal device switches. Before and after the terminal device switches, the order of candidate cells configured with random access resources is fixed. Therefore, the correspondence between different values ​​and candidate cells in the first rule is fixed. The candidate cells may include the service cell of the terminal device (for example, the second cell accessed after the terminal device switches), wherein different values ​​may be understood as values ​​other than the minimum value, and the first field of the minimum value may correspond to the service cell of the terminal device (for example, the first field of the minimum value corresponds to the first cell before the terminal device switches, and may also correspond to the second cell after the terminal device switches). It can be seen that for the service cell of the terminal device, it may correspond to the first field of two values, including the first field of the minimum value, and may also include the first field of the value determined according to the order of the candidate cells configured with random access resources before the switch.

[0031] For example, before the terminal device switches, it accesses cell 1, and cell 1 corresponds to the first field with a value of '00', and corresponds to the first field with a value of '01'. Cell 2, as a candidate cell, corresponds to the first field with a value of '10'. After the terminal device switches from cell 1 to cell 2, cell 2 corresponds to the first field with a value of '00', and corresponds to the first field with a value of '10', and cell 1 corresponds to the first field with a value of '01'. It can be seen that after the terminal device switches, cell 2, as the service cell of the terminal device, can correspond to the first field with the minimum value ('00') or the first field with the original value before switching ('10').

[0032] In combination with the first aspect, in certain implementations of the first aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched. The first rule is updated as follows: the first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

[0033] It should be understood that before the terminal device switches, the first field of the first value corresponds to the first cell; after the terminal device switches, the first field of the first value corresponds to the second cell. The first field of the first value corresponds to the serving cell of the terminal device. Due to the switching of the terminal device, the serving cell of the terminal device is also constantly changing, and the cell corresponding to the first field of the first value will also constantly change with the switching of the terminal device.

[0034] It should be noted that before switching to the second cell, the terminal device is connected to the first network device of the first cell. The first cell is a cell configured with a random access resource configuration. It can be understood that the random access resource configuration of the first cell also belongs to the random access resource configuration of the candidate cell. For example, the random access resource configuration of the first cell also exists in the random access resource configuration of the LTM candidate cell.

[0035] Based on the above solution, when the terminal device switches from the first cell to the second cell, the first field of the first value is updated from corresponding to the first cell to corresponding to the second cell. At the same time, the first cell is updated to correspond to the first field of the fifth value. The fifth value may be the same as or different from the second value. Whether the fifth value is the same as the second value is related to one of the order of the candidate cells configured with random access resources, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0036] In combination with the first aspect, in certain implementations of the first aspect, the updated first rule is related to one of the following: the order of candidate cells configured with random access resource configurations, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0037] It should be understood that the updated first rule is determined based on one of the following: the order of candidate cells configured with random access resources, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0038] The first order may be an initial default order or an order predefined according to certain rules. The order of the candidate cell identifiers may also be the order of the candidate cell physical identifiers.

[0039] It should be noted that when the updated first rule is related to the order of candidate cells configured with random access resources, the fifth value may be different from the second value; when the updated first rule is related to the first order, the fifth value may be different from the second value; when the updated first rule is related to the correspondence between the first field of the second value, the fifth value is the same as the second value; when the updated first rule is related to the order of the identifiers of the candidate cells, the fifth value may be different from the second value.

[0040] Based on the above solution, when a terminal device switches between different cells, the first rule can be dynamically updated based on the order of the candidate cells configured with random access resource configurations, the correspondence between the first order and the second value of the first field, the order of the candidate cell identifiers, etc. The random access resource configuration of the original serving cell accessed by the terminal device also belongs to the random access resource configuration of the candidate cell, allowing the terminal device to flexibly switch back and forth between different candidate cells.

[0041] With reference to the first aspect, in certain implementations of the first aspect, the order of the candidate cells configured with random access resources is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

[0042] It can also be understood that the order of the candidate cells configured with random access resource configurations is related to the ascending order of the logical identifiers of the candidate cells configured with random access resources.

[0043] In combination with the first aspect, in certain implementations of the first aspect, when the first field of the first value corresponds to the service cell to which the terminal device is currently connected, or corresponds to the service cell after the terminal device is switched, the first value is the minimum value.

[0044] It should be understood that when the first field of the first value corresponds to the first cell accessed by the terminal device before switching, or the second cell after the terminal device switches, the first value is the minimum value. The first value being the minimum value may refer to the minimum value of an N-bit binary number, where N is greater than or equal to 1, or may refer to the minimum value of a decimal number. For example, the first value may be '0', '00', or '000'.

[0045] Based on the above scheme, the first rule can preset the first field of the minimum value to correspond to the service cell of the terminal device. As the service cell of the terminal device changes, the cell corresponding to the first field of the minimum value will also change, and the cells corresponding to the first fields of other values ​​may also change accordingly.

[0046] In combination with the first aspect, in some implementations of the first aspect, the first information includes a second field, and the second field is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell.

[0047] It should be understood that the first information may also include a second field for indicating whether the terminal device triggers sending a random access request message 1 to the currently accessed serving cell. The second field may be a newly added bit in the first information.

[0048] Optionally, the second field may be enabled or disabled in the RRC configuration DCI format.

[0049] Based on the above solution, the terminal device can be displayed and instructed to switch to a candidate cell or trigger access to the current service cell through the second field in the first information, so that the terminal device can flexibly switch back and forth between different cells.

[0050] In combination with the first aspect, in certain implementations of the first aspect, when the value of the second field is the sixth value, the first field is a fill field, and the second cell is determined based on the first information and the first rule, including: determining to send a random access request message 1 to the first cell based on the second field in the first information.

[0051] Exemplarily, when the sixth value is 1, the second field is used to indicate that the terminal device can trigger random access to the currently accessed serving cell (first cell). At this time, the value of the first field can be regarded as meaningless, and the terminal device can ignore the first field or regard the first field as a filler bit. The PDCCH used to transmit the first information is only used to indicate the random access resources of the currently accessed serving cell (first cell).

[0052] In combination with the first aspect, in certain implementations of the first aspect, when the value of the second field is the seventh value, before determining the second cell based on the first information and the first rule, the method also includes: determining not to send a random access request message 1 to the first cell based on the second field in the first information.

[0053] Exemplarily, when the seventh value is 0, the second field is used to indicate that the terminal device cannot trigger random access to the currently accessed serving cell (first cell). At this time, the currently accessed serving cell does not belong to the candidate cell, and the PDCCH used to transmit the first information is only used to indicate the random access resources of the candidate cell. The value of the first field corresponds to the candidate cell containing the RACH.

[0054] In a second aspect, a communication method is provided, including: a first network device sends first information to a terminal device, the first information being used to instruct the terminal device to determine a first cell or a second cell according to a first rule; wherein the first cell belongs to the first network device, the first cell is the service cell currently accessed by the terminal device, and the first information includes a first field, the first field being used to indicate a candidate cell; or the first field is used to indicate the candidate cell and the service cell currently accessed by the terminal device, the second cell belongs to the candidate cell, the second cell belongs to the first network device, or the second cell belongs to the second network device, the first rule is used to indicate the correspondence between the first field and the candidate cell, or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

[0055] In combination with the second aspect, in certain implementations of the second aspect, the first cell is a cell configured with random access resource configuration, and the first rule includes: the first field of the first value corresponds to the first cell, and the first fields of other values ​​correspond to different candidate cells; the first information includes the first field of the second value.

[0056] In combination with the second aspect, in certain implementations of the second aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched, and the first rule is: the first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; wherein, the first rule is determined according to the order of the candidate cells configured with random access resource configurations.

[0057] In combination with the second aspect, in certain implementations of the second aspect, the first field of the second value corresponds to the second cell, wherein the fourth value is a minimum value.

[0058] In combination with the second aspect, in certain implementations of the second aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched, and the first rule is updated as follows: the first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

[0059] In combination with the second aspect, in certain implementations of the second aspect, the updated first rule is related to one of the following: the order of candidate cells configured with random access resource configurations, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0060] In combination with the second aspect, in certain implementations of the second aspect, the order of the candidate cells configured with random access resources is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

[0061] In combination with the second aspect, in certain implementations of the second aspect, when the first field of the first value corresponds to the service cell to which the terminal device is currently connected, or corresponds to the service cell after the terminal device is switched, the first value is the minimum value.

[0062] In combination with the second aspect, in some implementations of the second aspect, the first information includes a second field, and the second field is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell.

[0063] In combination with the second aspect, in some implementations of the second aspect, when the value of the second field is the sixth value, the first field is a padding field.

[0064] In a third aspect, a communication device is provided, including: a transceiver unit for receiving first information from a first network device, a first cell belonging to the first network device, the first cell being the service cell currently accessed by the communication device, the first information including a first field, the first field being used to indicate a candidate cell, or the first field being used to indicate the candidate cell and the service cell currently accessed by the communication device; a processing unit for determining the first cell or the second cell based on the first information and a first rule, the second cell belonging to the candidate cell, the second cell belonging to the first network device, or the second cell belonging to the second network device, wherein the first rule is used to indicate the correspondence between the first field and the candidate cell; or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the communication device.

[0065] In combination with the third aspect, in certain implementations of the third aspect, the processing unit is further configured to send a random access request message 1 to the first cell or the second cell according to the first information and the first rule.

[0066] In combination with the third aspect, in certain implementations of the third aspect, the first cell is a cell configured with random access resource configuration, and the first rule includes: the first field of the first value corresponds to the first cell, and the first fields of other values ​​correspond to different candidate cells; the first information includes the first field of the second value.

[0067] In combination with the third aspect, in certain implementations of the third aspect, the processing unit is specifically configured to send a random access request message 1 to the first cell according to the first field of the first value and the first rule.

[0068] In combination with the third aspect, in certain implementations of the third aspect, the processing unit is specifically configured to send the random access request message 1 to different candidate cells according to the first field with other values ​​and the first rule.

[0069] In combination with the third aspect, in certain implementations of the third aspect, after the communication device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the communication device is switched, and the first rule is: the first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; wherein, the first rule is determined according to the order of the candidate cells configured with random access resource configurations.

[0070] In combination with the third aspect, in certain implementations of the third aspect, the first field of the second value corresponds to the second cell, wherein the fourth value is a minimum value.

[0071] In combination with the third aspect, in certain implementations of the third aspect, after the communication device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the communication device is switched, and the first rule is updated as follows: the first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

[0072] In combination with the third aspect, in certain implementations of the third aspect, the updated first rule is related to one of the following: the order of candidate cells configured with random access resource configurations, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0073] In combination with the third aspect, in certain implementations of the third aspect, the order of the candidate cells configured with random access resources is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

[0074] In combination with the third aspect, in certain implementations of the third aspect, when the first field of the first value corresponds to the service cell currently accessed by the communication device, or corresponds to the service cell after the communication device is switched, the first value is the minimum value.

[0075] In combination with the third aspect, in certain implementations of the third aspect, the first information includes a second field, and the second field is used to indicate whether the communication device triggers sending a random access request message 1 to the first cell.

[0076] In combination with the third aspect, in certain implementations of the third aspect, when the value of the second field is the sixth value, the first field is a fill field, and the processing unit is specifically used to determine to send a random access request message 1 to the first cell based on the second field in the first information.

[0077] In combination with the third aspect, in certain implementations of the third aspect, when the value of the second field is the seventh value, before determining the second cell based on the first information and the first rule, the processing unit is also used to determine not to send a random access request message 1 to the first cell based on the second field in the first information.

[0078] In a fourth aspect, a communication device is provided, including: a transceiver unit, used to send first information to a terminal device, the first information being used to instruct the terminal device to determine a first cell or a second cell according to a first rule; wherein the first cell belongs to the communication device, the first cell is the service cell currently accessed by the terminal device, and the first information includes a first field, and the first field is used to indicate a candidate cell; or the first field is used to indicate the candidate cell and the service cell currently accessed by the terminal device, the second cell belongs to the candidate cell, the second cell belongs to the communication device, or the second cell belongs to a second network device, the first rule is used to indicate the correspondence between the first field and the candidate cell, or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

[0079] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first cell is a cell configured with random access resource configuration, and the first rule includes: the first field of the first value corresponds to the first cell, and the first fields of other values ​​correspond to different candidate cells; the first information includes the first field of the second value.

[0080] In combination with the fourth aspect, in certain implementations of the fourth aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched, and the first rule is: the first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; wherein, the first rule is determined according to the order of the candidate cells configured with random access resource configurations.

[0081] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first field of the second value corresponds to the second cell, wherein the fourth value is the minimum value.

[0082] In combination with the fourth aspect, in certain implementations of the fourth aspect, after the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the service cell after the terminal device is switched, and the first rule is updated as follows: the first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

[0083] In combination with the fourth aspect, in certain implementations of the fourth aspect, the updated first rule is related to one of the following: the order of candidate cells configured with random access resource configurations, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

[0084] In combination with the fourth aspect, in certain implementations of the fourth aspect, the order of the candidate cells configured with random access resources is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

[0085] In combination with the fourth aspect, in certain implementations of the fourth aspect, when the first field of the first value corresponds to the service cell to which the terminal device is currently connected, or corresponds to the service cell after the terminal device is switched, the first value is the minimum value.

[0086] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first information includes a second field, and the second field is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell.

[0087] In combination with the fourth aspect, in certain implementations of the fourth aspect, when the value of the second field is the sixth value, the first field is a padding field.

[0088] In a fifth aspect, a communication device is provided, comprising: a processor coupled to a memory, the memory being used to store a computer program, the processor being used to run the computer program, so that the communication device executes the method as described in the first aspect and any possible implementation thereof.

[0089] In a sixth aspect, a communication device is provided, comprising: a processor coupled to a memory, the memory being used to store a computer program, the processor being used to run the computer program, so that the communication device executes the method as described in the second aspect and any possible implementation thereof.

[0090] In the seventh aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a computer, the computer executes the communication method that can be implemented in the first aspect and the first aspect, or the second aspect and the second aspect.

[0091] In an eighth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute any of the communication methods that can be implemented in the first aspect and the first aspect, or the second aspect and the second aspect.

[0092] In the ninth aspect, a chip is provided, which includes a processor and a data interface. The processor reads instructions stored in a memory through the data interface to execute any communication method that can be implemented in the first aspect and the first aspect, or the second aspect and the second aspect.

[0093] In combination with the ninth aspect, in one possible implementation, the processor is coupled to the memory through an interface.

[0094] In combination with the ninth aspect, in one possible implementation, the chip system also includes a memory, in which a computer program or computer instructions are stored. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] FIG1 is a schematic diagram of a scenario provided in an embodiment of the present application.

[0096] FIG2 is a schematic flow chart of a communication method provided in an embodiment of the present application.

[0097] FIG3 is a schematic diagram of a corresponding relationship provided in an embodiment of the present application.

[0098] FIG4 is a schematic diagram of a corresponding relationship provided in an embodiment of the present application.

[0099] FIG5 is a schematic diagram of a corresponding relationship provided in an embodiment of the present application.

[0100] FIG6 is a schematic diagram of a field structure of first information provided in an embodiment of the present application.

[0101] FIG7 is a schematic block diagram of a communication device of the present application.

[0102] FIG8 is a schematic block diagram of a terminal device of the present application.

[0103] FIG9 is a schematic block diagram of another communication device of the present application.

[0104] FIG10 is a schematic block diagram of a network device of the present application. DETAILED DESCRIPTION

[0105] The technical solution in this application will be described below with reference to the accompanying drawings.

[0106] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WiMAX) communication system, future fifth generation (5G) system or new radio (NR), etc.

[0107] The terminal equipment (UE) involved in the embodiments of the present application may include various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem. The terminal equipment may be a mobile station (MS), a subscriber unit (subscriber unit), a cellular phone (cellular phone), a smart phone (smart phone), a wireless data card, a personal digital assistant (PDA), a tablet computer, a wireless modem (modem), a handheld device (handset), a laptop computer (laptop computer), a machine type communication (MTC) terminal, etc., and the embodiments of the present application are not limited to this.

[0108] The network device in the embodiment of the present application may also be referred to as an access network device. The network device may be a base transceiver station (BTS) in a global system for mobile communications (GSM) system or a code division multiple access (CDMA) system, a base station (NodeB, NB) in a wideband code division multiple access (WCDMA) system, an evolved NodeB (eNB or eNodeB) in an LTE system, or a wireless controller in a cloud radio access network (CRAN) scenario, or the network device may be a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in a future 5G network, or a network device in a future evolved public land mobile network (PLMN) network, for example, a transmission point (transmission reception point (TRP) or TP) in an NR system, a base station (gNB) in an NR system, one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G system, etc. The embodiment of the present application is not particularly limited to this.

[0109] The embodiments of the present application do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application. As long as it is possible to communicate according to the method provided by the embodiments of the present application by running a program that records the code of the method provided by the embodiments of the present application, for example, the execution subject of the method provided by the embodiments of the present application can be a terminal device or a network device, or a functional module in the terminal device or the network device that can call and execute the program.

[0110] In addition, various aspects or features of the present application can be implemented as methods, devices or products using standard programming and / or engineering techniques. The term "product" as used in this application covers computer programs that can be accessed from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or magnetic tapes, etc.), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memories (EPROMs), cards, sticks or key drives, etc.). In addition, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0111] The embodiments of the present application do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application. As long as it is possible to communicate according to the method provided by the embodiments of the present application by running a program that records the code of the method provided by the embodiments of the present application, for example, the execution subject of the method provided by the embodiments of the present application can be a terminal device or a network device, or a functional module in the terminal device or the network device that can call and execute the program.

[0112] The following introduces the technical terms involved in the embodiments of this application.

[0113] Beam: A beam is a communication resource. A beam can be a wide beam, a narrow beam, or other types of beams. The technology for forming the beam can be beamforming technology or other technical means. Beamforming technology can specifically be digital beamforming technology, analog beamforming technology, and hybrid digital / analog beamforming technology. Different beams can be considered as different resources. The same information or different information can be sent through different beams. Optionally, multiple beams with the same or similar communication characteristics can be regarded as a beam. A beam can include one or more antenna ports for transmitting data channels, control channels, and detection signals, etc. For example, a transmit beam can refer to the distribution of signal strength in different directions in space after the signal is transmitted by the antenna, and a receive beam can refer to the distribution of signal strength in different directions in space of the wireless signal received from the antenna. It can be understood that one or more antenna ports forming a beam can also be regarded as an antenna port set.

[0114] When using low-frequency or medium-frequency bands, signals can be sent omnidirectionally or through a wider angle. When using high-frequency bands, thanks to the smaller carrier wavelength of high-frequency communication systems, antenna arrays consisting of many antenna elements can be arranged at the transmitting and receiving ends. The transmitting end sends signals with certain beamforming weights, so that the transmitted signals form a beam with spatial directionality. At the same time, the receiving end uses an antenna array with certain beamforming weights to receive the signals, which can improve the received signal power at the receiving end and combat path loss.

[0115] Reference Signal: According to the Long Term Evolution (LTE) / NR protocol, at the physical layer, uplink communication includes the transmission of uplink physical channels and uplink signals. Uplink physical channels include the random access channel (PRACH), the physical uplink control channel (PUCCH), and the physical uplink shared channel (PUSCH). Uplink signals include the sounding reference signal (SRS), the uplink control channel demodulation reference signal (PUCCH-DMRS), the uplink data channel demodulation reference signal (PUSCH-DMRS), the uplink phase noise tracking reference signal (PTRS), and the uplink positioning RS. Downlink communication includes the transmission of downlink physical channels and downlink signals. The downlink physical channels include the physical broadcast channel (PBCH), the physical downlink control channel (PDCCH), the physical downlink shared channel (PDSCH), etc. The downlink signals include the primary synchronization signal (PSS) / secondary synchronization signal (SSS), the downlink control channel demodulation reference signal PDCCH-DMRS, the downlink data channel demodulation reference signal PDSCH-DMRS, the phase noise tracking signal PTRS, the channel status information reference signal (CSI-RS), the cell signal (CRS) (NR does not have), the time / frequency tracking reference signal (TRS) (LTE does not have), the LTE / NR positioning signal (positioning RS), etc.

[0116] Timing Advance (TA): Timing advance is used for UE uplink transmissions. It means that the UE sends data packets in advance according to instructions. The base station sends a timing advance command (TAC) to the UE, informing it of the timing advance time. A key feature of uplink transmission is orthogonal multiple access (TPA) between different UEs in time and frequency. This means that uplink transmissions from different UEs in the same cell do not interfere with each other. To ensure orthogonality in uplink transmissions and avoid intra-cell interference, the TRP requires that signals from different UEs in the same subframe but on different frequency resources arrive at the TRP at essentially aligned times. The TRP can correctly decode uplink data as long as it receives the uplink data transmitted by the UE within the cyclic prefix (CP). Therefore, uplink synchronization requires that signals from different UEs in the same subframe arrive at the TRP within the CP. From the UE's perspective, the TA is essentially a negative offset between the start time of the received downlink subframe and the time of the uplink subframe transmission. By appropriately controlling the TRP offset for each UE, the arrival time of uplink signals from different UEs at the TRP can be controlled. For UEs that are farther from the TRP, due to the larger transmission delay, uplink data must be sent earlier than UEs that are closer to the TRP.

[0117] Figure 1 shows a schematic block diagram of a wireless communication system 100 according to an embodiment of the present application. The wireless communication system 100 includes at least two cells, for example, a serving cell belonging to a first network device 110 and a candidate cell belonging to a second network device 120. When a terminal device 130 moves from a serving cell to a candidate cell, a handover may occur, i.e., switching from the serving cell to the candidate cell.

[0118] It should be noted that when the terminal device switches to a candidate cell, the candidate cell can be understood as a new serving cell, and the original serving cell can be understood as a new candidate cell.

[0119] It should be understood that the candidate cell may be a neighboring cell of the serving cell. In the embodiments of the present application, "first", "second", "third", "fourth", etc. are only for distinction, and the first, second, third, and fourth are not intended to limit the embodiments of the present application.

[0120] It should be understood that in the embodiments of the present application, a network device may have one or more cells. The serving cell and the candidate cell may also belong to the same network device, that is, the first network device and the second network device may be the same network device. In this case, the terminal device performs a handover within the network device.

[0121] Optionally, the serving cell and the candidate cell may also belong to different network devices, that is, the first network device and the second network device may be different network devices. In this case, the terminal device performs handover between network devices.

[0122] It should be noted that the communication method provided in the embodiment of the present application can take a single network device and a terminal device as an example, and the network device can transmit data or control signaling to the terminal device.

[0123] Specifically, based on the configuration information of the network device, the terminal device can report the measurement result of the reference signal for switching the serving beam of the terminal. Each cell (including the serving cell and the candidate cell) can be configured with multiple carriers.

[0124] As shown in Figure 1, the current terminal device 130 is controlled by the first network device of the serving cell, and the first network device controls the terminal device to switch to the candidate cell by sending a switching message. At present, the first network device triggers the terminal device to initiate a random access channel (RACH) to the candidate cell through the downlink control channel (physical downlink control channel, PDCCH). This method requires the use of downlink control indication (DCI) signaling. This function is usually applicable to uplink asynchronous scenarios, that is, the terminal device can receive downlink normally, but the uplink transmission timing has failed or lost. The network device requires the terminal device to re-obtain the timing advance (TA) through the random access process for transmitting uplink data.

[0125] It should be noted that, when DCI signaling is currently used to trigger the terminal device to initiate RACH to the candidate cell, the network device needs to carry DCI signaling with format 0_1 ​​in the PDCCH.

[0126] Optionally, the DCI signaling may include the following fields: preamble index (random access preamble index); normal uplink carrier or supplementary uplink carrier (uplink indicator / supplement uplink indicator); synchronization / broadcast signal index (synchronization signal index / physical broadcasting channel index); mask index (physical random access channel mask index); and reserved bits. Some of the reserved bits may be used to indicate candidate cells for random access.

[0127] Based on this, the terminal device can continue to switch to other candidate cells without receiving a radio resource control (RRC) reconfiguration command after switching to a new cell. Other candidate cells can also be the original serving cell, which is equivalent to the terminal device switching to a new cell and switching back to the original serving cell based on the handover command issued by the new cell without reconfiguration.

[0128] However, if the reserved 2 or 3 bits in the DCI signaling are used to indicate the candidate cell, the correspondence between the field used to indicate the candidate cell and the candidate cell needs to be clearly defined. Otherwise, the terminal device will not be able to determine which cell's random access resources will be used to send the random access request message 1, thereby affecting the switching process of the terminal device.

[0129] In view of the above problems, the embodiments of the present application provide a communication method and a communication device, which clearly define the corresponding relationship between the fields used to indicate candidate cells and the candidate cells, and clarify how DCI instructs the terminal device to initiate random access to the candidate cells, thereby improving the switching efficiency of the terminal device.

[0130] In the following, for the purpose of facilitating understanding and explanation, the execution process and actions of the communication method in the present application in the communication system are described as an example rather than a limitation.

[0131] As shown in Figure 2, a schematic flow chart of a communication method provided in an embodiment of the present application is shown. The method shown in Figure 2 can be applied to the communication system shown in Figure 1. The method 200 shown in Figure 2 includes:

[0132] S201, the terminal device receives the first information, and accordingly, the first network device sends the first information.

[0133] It should be noted that the first cell belongs to the first network device, and the first cell is the serving cell currently accessed by the terminal device. As the terminal device switches, the serving cell currently accessed by the terminal device may change.

[0134] Exemplarily, the first information may be DCI sent by the first network device to the terminal device via the PDCCH, where the DCI includes a field for indicating the candidate cell, for example, the field may be a "cell indicator" field.

[0135] In one implementation, the first information includes a first field, and the first field is used to indicate a candidate cell, or the first field is used to indicate a candidate cell and a serving cell currently accessed by the terminal device.

[0136] Exemplarily, the first field is a "cell indicator" field. When the serving cell currently accessed by the terminal device is the first cell and the candidate cell is the second cell, the first field can be used to indicate the second cell, or to indicate the first cell and the second cell.

[0137] It should be understood that the embodiment of the present application does not limit the number of bits in the first field, which can be 2 bits or 3 bits. C represents the number of candidate cells configured with RACH resources, and "+1" indicates that the serving cell is included, that is, N is the logarithm of (C+1) with base 2, and then rounded up to an integer.

[0138] S202: The terminal device determines the first cell or the second cell according to the first information and the first rule.

[0139] It should be noted that the second cell is a candidate cell, the second cell belongs to the first network device, or the second cell belongs to the second network device. The second cell and the first cell can be neighboring cells. If the terminal device switches from the first cell to the second cell, the second cell can be understood as the serving cell after the terminal device switches.

[0140] It should be understood that when the second cell belongs to the first network device, it corresponds to the scenario in which the terminal device within the first network device switches between cells; when the second cell belongs to the second network device, it corresponds to the scenario in which the terminal device between multiple network devices switches between cells.

[0141] It should be understood that the first rule is used to indicate the correspondence between the first field and the candidate cell; or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the serving cell currently accessed by the terminal device. The first rule can be replaced by "correspondence", "association", etc.

[0142] It should be understood that the first rule can also be used to indicate the correspondence between the value of the first field and the identifier of the candidate cell; the first rule can also be used to indicate the correspondence between the value of the first field and the physical identifier of the candidate cell; the first rule can also be used to indicate the correspondence between the value of the first field and the logical identifier of the candidate cell, etc.

[0143] It should be understood that the network device can configure at least one cell or cell group for the terminal device as a candidate cell to be switched by the terminal device. At the same time, the network device configures an identifier for these cells or cell groups, which can be understood as a logical identifier and can be different from the cell identifier or the cell physical identifier (PCI). The service cell accessed by the terminal device can also be used as a candidate cell and is associated with the identifier of the candidate cell. Generally speaking, the service cell configuration as a candidate cell can be used in scenarios where the terminal device continuously switches between cells, that is, after the terminal device switches from the currently accessed service cell to other candidate cells, it can switch back to the original service cell without reconfiguration.

[0144] Exemplarily, when the first field is used to indicate a candidate cell, the first rule is used to indicate the correspondence between the first field and the candidate cell; when the first field is used to indicate the candidate cell and the service cell currently accessed by the terminal device, the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

[0145] It should be understood that when the first rule is used to indicate the correspondence between the first field and the candidate cell, the terminal device can determine the second cell based on the first information and the first rule; when the first rule is used to indicate the correspondence between the first field and the candidate cell and the relationship between the first field and the service cell currently accessed by the terminal device, the terminal device can determine the first cell and / or the second cell based on the first information and the first rule.

[0146] Furthermore, the terminal device may send a random access request message 1 to the first cell or the second cell according to the first information and the first rule.

[0147] Specifically, the terminal device may send a random access request message 1 to the first cell or the second cell based on the value of the first field and the first rule. Alternatively, the terminal device may send a random access request message 1 to the first cell or the second cell based on the value of the first field and the association relationship. Alternatively, the terminal device may send a random access request message 1 to the first cell or the second cell based on the value of the first field and the corresponding relationship.

[0148] That is to say, to which cell the terminal device sends the random access request message 1 is related to the value of the first field and the correspondence between the value of the first field and the identifier of the cell.

[0149] In one implementation, the first cell is a cell configured with random access resources, the first rule includes: a first field with a first value corresponds to the first cell, and first fields with other values ​​correspond to different candidate cells. The first information includes a first field with a second value.

[0150] Specifically, the terminal device may send a random access request message 1 to the first cell according to the first field of the first value and the first rule. The terminal device may send a random access request message 1 to the second cell according to the first field of the second value and the first rule.

[0151] Exemplarily, the random access resource configuration of the candidate cell may be a layer 1, layer 2 triggered mobility (L1 / L2 triggered mobility, LTM) candidate cell resource configuration. The first cell is a cell configured with random access resources. It can be understood that the first cell can also be used as a candidate cell for the terminal device. After the terminal device switches from the first cell to other cells, the terminal device can also switch back to the first cell from other cells.

[0152] It should be understood that the first field with other values ​​has a one-to-one correspondence with different candidate cells.

[0153] The terminal device can initiate random access to different candidate cells based on the first field with other values ​​and the first rule.

[0154] It should be noted that, based on the first field including the second value in the first information, the terminal device can determine that the second cell is a candidate cell according to the first field of the second value in the first information and the first rule.

[0155] It is understandable that the first information may also include a first field with other values, which is not limited in this application.

[0156] It should be noted that the first rule can be used to indicate the correspondence between the first field and the cell. The cell may include a candidate cell, or may include a candidate cell and a service cell currently accessed by the terminal device. As the terminal device switches, the service cell currently accessed by the terminal device may also change. The cell accessed by the terminal device before the switch can be understood as the service cell currently accessed by the terminal device, and the cell accessed by the terminal device after the switch can be understood as the service cell after the terminal device switches. When the terminal device switches, the service cell after the terminal device switches can also be understood as the service cell currently accessed by the terminal device. The "current" and the "current" before the switch may not be the same moment.

[0157] It should be understood that the correspondence between the first field and the cell can be fixed or can be flexibly changed as the terminal device switches between different cells. In other words, the first rule can be fixed or can be dynamically updated.

[0158] Based on this, several possible situations of the first rule are introduced below.

[0159] Method 1: The first rule is fixed.

[0160] It should be noted that the fixed first rule can be understood as the corresponding relationship between the value of the first field and the cell is fixed. The cell may include a candidate cell and a serving cell currently accessed by the terminal device.

[0161] It should be understood that the fixity of the first rule is relative, and not all values ​​of the first field and the corresponding relationship between the cell is fixed. At least except for the minimum value, the corresponding relationship between the first field and the cell is fixed.

[0162] In an embodiment of the present application, a terminal device receives first information from a first network device in a first cell, the first information including a first field, the first field being used to indicate a candidate cell; or the first field being used to indicate a candidate cell and a serving cell currently accessed by the terminal device; the terminal device determines the first cell or the second cell based on the first information and a first rule, wherein the first cell is the serving cell currently accessed by the terminal device, the second cell is a candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell; or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the serving cell currently accessed by the terminal device. Specifically, the first field of the first value corresponds to the first cell (the serving cell currently accessed by the terminal device), and the first field of the second value corresponds to the second cell (one of the candidate cells of the terminal device). The terminal device determines the second cell based on the first field of the second value in the first information and the first rule, and sends a random access request message 1 to the second cell. After the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the serving cell after the terminal device switches. The first rule after switching is: the first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell. The first rule is determined according to the order of candidate cells configured with random access resources.

[0163] It should be understood that the candidate cell configured with random access resources can be understood as the candidate cell's random access resource configuration existing in the LTM candidate cell random access resource configuration. The first cell accessed by the terminal device before handover is also configured with random access resources, and the random access resource configuration of the first cell also exists in the LTM candidate cell random access resource configuration.

[0164] It should be noted that the order of the candidate cells configured with random access resources is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

[0165] It can be seen that the order of candidate cells configured with random access resources is fixed before and after the terminal device is switched. Therefore, the correspondence between different values ​​and candidate cells in the first rule is fixed. For example, a first field with a value of 00 corresponds to cell 1 before and after the switch, and a first field with a value of 01 corresponds to cell 2 before and after the switch.

[0166] It should be noted that before switching to the second cell, the terminal device is connected to the first network device of the first cell. Among them, the first cell is a cell configured with random access resource configuration, which can be understood as the random access resource configuration of the first cell also belonging to the random access resource configuration of the candidate cell. For example, the RACH resources of the first cell exist in the LTM configuration. At this time, the value of the DCI field can be mapped according to the order of the list of candidate cells containing RACH resources in the LTM configuration (the logical identifier of the candidate cells configured with random access resources is in ascending order), that is, the correspondence between the first field and the candidate cell is mapped. Among them, the relationship between the first field and the candidate cell can also be understood as the correspondence between the value of the first field and the candidate cell.

[0167] Exemplarily, when the correspondence between the value of the first field and the candidate cells is mapped according to the order of the candidate cells containing RACH resources in the LTM configuration, during the switching of the terminal device between cells, the value of the first field corresponds to the candidate cell one-to-one, and the correspondence does not change with the switching of the terminal device. Unless, RRC reconfigures the candidate cell list of LTM. Among them, the one-to-one correspondence between the value of the first field and the candidate cell can be understood as the one-to-one correspondence between the value of the first field and the physical cell identity (PCI) of the candidate cell.

[0168] For example, in RRC configuration signaling, LTM configuration includes the following correspondence:

[0169] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538 (with RACH configuration)

[0170] LTM-candidate Cell ID = 1, corresponding to Physical cell ID = 1002 (with RACH configuration)

[0171] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123 (current serving cell, with RACH configuration)

[0172] LTM-candidate Cell ID = 3, corresponding to Physical cell ID = 356

[0173] LTM-candidate Cell ID = 4, corresponding to Physical cell ID = 432

[0174] LTM-candidate Cell ID = 5, corresponding to Physical cell ID = 974

[0175] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 736 (with RACH configuration)

[0176] LTM-candidate Cell ID = 7, corresponding to Physical cell ID = 176

[0177] Based on the order of the list of candidate cells with RACH resources in the above LTM configuration (the logical identifiers of the candidate cells configured with random access resources are ordered from small to large), mapped to the first field with different values, we can get:

[0178] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538, corresponding to '00'

[0179] LTM-candidate Cell ID = 1, corresponding to Physical cell ID = 1002, corresponding to '01'

[0180] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123, corresponding to '10'

[0181] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 736, corresponding to '11'

[0182] Candidate cell 538 corresponds to the first field with a value of '00'; candidate cell 1002 corresponds to the first field with a value of '01'; candidate cell 123 corresponds to the first field with a value of '10'; and candidate cell 736 corresponds to the first field with a value of '11'.

[0183] It can be seen that the physical identifier of the candidate cell can be corresponded to the first field with different values. When the terminal device receives the first information including the first field, it can determine the candidate cell to be switched.

[0184] It should be noted that the candidate cells in the LTM configuration may also not contain RACH resources, for example, candidate cell 356, candidate cell 432, candidate cell 974, and candidate cell 176. Candidate cells without RACH resources may also occupy the first field of the corresponding value, but the first field of the corresponding value corresponding to the candidate cell without RACH resources may be ignored by the terminal device, or will not be used to indicate the candidate cell to which the terminal device is to switch.

[0185] For example, if the first cell is candidate cell 123, and the second cell is candidate cell 538. Before the terminal device switches, the terminal device accesses the first cell, the first value is '10', and the second value is '00'. After the terminal device switches, the terminal device accesses the second cell, the third value is '10', and the fourth value is '00'. Among them, the first field of the first value and the first field of the third value correspond to the first cell, the first field of the second value and the first field of the fourth value correspond to the second cell, the first value is the same as the third value, and the second value is the same as the fourth value. It can be seen that based on the above-mentioned first rule, before and after the terminal device switches, the one-to-one correspondence between the value of the first field and the cell is fixed.

[0186] Exemplarily, when mapping the correspondence between the value of the first field and the candidate cells according to the order of the candidate cells containing RACH resources in the LTM configuration, during the switching of the terminal device between cells, the value of the first field corresponds to the candidate cells and the current serving cell according to the configuration order or identifier of the candidate cells, and, except for the serving cell, the correspondence between the non-serving cells in the correspondence does not change with the switching of the terminal device. Unless, RRC reconfigures the candidate cell list of LTM.

[0187] For example, in RRC configuration signaling, LTM configuration includes the following correspondence:

[0188] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538 (with RACH configuration)

[0189] LTM-candidate Cell ID = 1, corresponding to Physical cell ID = 1002

[0190] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123 (current serving cell, with RACH configuration)

[0191] LTM-candidate Cell ID = 3, corresponding to Physical cell ID = 356

[0192] LTM-candidate Cell ID = 4, corresponding to Physical cell ID = 432

[0193] LTM-candidate Cell ID = 5, corresponding to Physical cell ID = 974

[0194] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 176 (with RACH configuration)

[0195] Based on the order of the list of candidate cells with RACH resources in the above LTM configuration (the logical identifiers of the candidate cells configured with random access resources are ordered from small to large), mapped to the first field with different values, we can get:

[0196] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123, is the current serving cell, corresponding to '00'

[0197] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538, corresponding to '01'

[0198] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123, which is the current serving cell and the second cell in the candidate cell list that is configured with random access resources, so it corresponds to '10'

[0199] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 176, corresponding to '11'

[0200] In this example, the serving cell is indicated by the minimum value of the first field. The remaining values ​​of the first field correspond to the candidate cells configured with random access resources. The corresponding order is from smallest to largest candidate cell configuration identifier, and the remaining values ​​of the first field, excluding the minimum value, correspond to them in ascending order.

[0201] It should be understood that in this application, the corresponding order can also be from large to small, or the corresponding order can be understood according to the physical cell identifier, or regardless of whether the candidate cell is configured with random access resources, it corresponds to the value of the first field.

[0202] The method of this example also includes that if the terminal device is triggered to send a random access request message 1 to the serving cell by the first field of the minimum value in the first information, the terminal device will attempt to receive a random access request response message (random access response, RAR) on the preconfigured time-frequency resources; if the terminal device is triggered to send a random access request message 1 to the serving cell by the first field of other values ​​other than the minimum value in the first information, the terminal device may no longer attempt or consider receiving a random access request response message for the random access request message 1. It should be understood that the other values ​​other than the minimum value in the above-mentioned first information are values ​​corresponding to the serving cell.

[0203] For example, in this example, the first field with the minimum value of '00' corresponds to cell PCI123 (the current serving cell), and the first field with the value of '10' also corresponds to cell PCI123. If the terminal device is triggered by the first field with the value of '00' to send a random access request message 1 to cell PCI123, the terminal device may attempt to receive a random access request response message on the preconfigured time-frequency resources; if the terminal device is triggered by the first field with the value of '10' to send a random access request message 1 to cell PCI123, the terminal device may no longer attempt or consider receiving a random access request response message for the random access request message 1.

[0204] For ease of understanding, as shown in FIG3 , a correspondence between the value of the first field before and after switching of a terminal device and the cell is shown.

[0205] Before switching, the first field with a value of '00' corresponds to the original serving cell (cell PCI123), the first field with a value of '01' corresponds to cell PCI538, the first field with a value of '10' corresponds to cell PCI123, and the first field with a value of '11' corresponds to cell PCI176.

[0206] After switching to cell PCI538, the first field with a value of '00' corresponds to the new service cell (cell PCI538), the first field with a value of '01' corresponds to cell PCI538, the first field with a value of '10' corresponds to cell PCI123, and the first field with a value of '11' corresponds to cell PCI176.

[0207] It can be seen that before and after the switching, except that the cell corresponding to '00' changes with the change of the serving cell of the terminal device, the cells corresponding to the values ​​of the first field '01', 10' and '11' are fixed.

[0208] In this example, the serving cell of the terminal device may correspond to two values ​​of the first field. For example, the serving cell of the terminal device is cell PCI123, and the corresponding first field values ​​are '00' and '10'.

[0209] Similarly, the terminal device switches continuously between cells. Based on Figure 3, after the terminal device switches to cell PCI538, it can also switch back to cell PCI123. After the terminal device switches back to cell PCI123, the first field with a value of '00' corresponds to cell PCI123, the first field with a value of '01' corresponds to cell PCI538, the first field with a value of '10' corresponds to cell PCI123, and the first field with a value of '11' corresponds to cell PCI176. Alternatively, after the terminal device switches to cell PCI538, it can also switch to cell PCI176. After the terminal device switches to cell PCI176, the first field with a value of '00' corresponds to cell PCI176, the first field with a value of '01' corresponds to cell PCI538, the first field with a value of '10' corresponds to cell PCI123, and the first field with a value of '11' corresponds to cell PCI176.

[0210] In the second method, the first rule can be updated dynamically.

[0211] It should be noted that the first rule of dynamic update can be understood as the correspondence between the value of the first field and the cell can be dynamically updated. The cell may include a candidate cell and a serving cell currently accessed by the terminal device.

[0212] In an embodiment of the present application, a terminal device receives first information from a first network device in a first cell, the first information including a first field, the first field being used to indicate a candidate cell; or the first field being used to indicate a candidate cell and a serving cell currently accessed by the terminal device; the terminal device determines the first cell or the second cell based on the first information and a first rule, wherein the first cell is the serving cell currently accessed by the terminal device, the second cell is a candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell; or the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the serving cell currently accessed by the terminal device. Specifically, the first field of the first value corresponds to the first cell (the serving cell currently accessed by the terminal device), and the first field of the second value corresponds to the second cell (one of the candidate cells of the terminal device). The terminal device determines the second cell based on the first field of the second value in the first information and the first rule, and sends a random access request message 1 to the second cell. After the terminal device switches from the first cell to the second cell, the first cell belongs to the candidate cell, and the second cell is the serving cell after the terminal device switches. The first rule after switching is updated as follows: the first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

[0213] It can be seen that in mode 2, before the terminal device switches, the first field of the first value corresponds to the first cell; after the terminal device switches, the first field of the first value corresponds to the second cell. The first field of the first value corresponds to the serving cell of the terminal device. Due to the switching of the terminal device, the serving cell of the terminal device is also constantly changing, and the cell corresponding to the first field of the first value will also constantly change with the switching of the terminal device.

[0214] It should be noted that before switching to the second cell, the terminal device is connected to the first network device of the first cell. The first cell is a cell configured with a random access resource configuration. It can be understood that the random access resource configuration of the first cell also belongs to the random access resource configuration of the candidate cell. For example, the random access resource configuration of the first cell also exists in the random access resource configuration of the LTM candidate cell.

[0215] In the first rule of the second method, when the first field of the first value corresponds to the serving cell of the terminal device (including the serving cell currently accessed by the terminal device and the serving cell after the terminal device switches, such as the first cell before switching and the second cell after switching mentioned above), the first value is the minimum value. For example, the first value can be '0', '00', or '000'.

[0216] Alternatively, a first field with a fixed value corresponds to the serving cell of the terminal device. For example, the fixed value may be the minimum value of the first field ('0', '00' or '000').

[0217] Exemplarily, when the terminal device accesses the first cell, the first cell is the serving cell currently accessed by the terminal device, and the first field of the first value corresponds to the first cell. When the terminal device accesses the second cell, the second cell is the serving cell after the terminal device is switched, and the first field of the first cell corresponds to the second cell.

[0218] It can be seen that in the second method, the cell corresponding to the first field of the first value can dynamically change according to the different serving cells of the terminal device. The value of the first field corresponds to the cell, and the corresponding relationship changes as the terminal device switches. Among them, the correspondence between the value of the first field and the cell can be understood as that the value of the first field corresponds to the physical identifier of the cell.

[0219] Based on the first rule of the second method, when the terminal device switches from the first cell to the second cell, the first field of the first value is updated from corresponding to the first cell to corresponding to the second cell. At the same time, the first cell is updated to correspond to the first field of the fifth value.

[0220] It should be understood that the fifth value may be the same as the second value or different from the second value.

[0221] Optionally, the fifth value is the same as the second value.

[0222] It should be noted that when the terminal device switches from the first cell to the second cell, the first cell corresponds to the value of the first field corresponding to the second cell before the switch. In other words, the correspondence between the values ​​of the first field is exchanged between the original serving cell (the first cell) and the new serving cell (the second cell).

[0223] For example, as shown in FIG4 , a correspondence between the value of the first field and the cell before and after the terminal device is switched is shown.

[0224] Before switching, the first field value of '000' corresponds to the original serving cell, the first field value of '001' corresponds to candidate cell 1, the first field value of '010' corresponds to candidate cell 2, the first field value of '011' corresponds to candidate cell 3, the first field value of '100' corresponds to candidate cell 4, the first field value of '101' corresponds to candidate cell 5, the first field value of '110' corresponds to candidate cell 6, and the first field value of '111' corresponds to candidate cell 7.

[0225] After switching to candidate cell 2, the first field with a value of '000' corresponds to the new service cell (candidate cell 2), the first field with a value of '001' corresponds to candidate cell 1, the first field with a value of '010' corresponds to the original service cell, the first field with a value of '011' corresponds to candidate cell 3, the first field with a value of '100' corresponds to candidate cell 4, the first field with a value of '101' corresponds to candidate cell 5, the first field with a value of '110' corresponds to candidate cell 6, and the first field with a value of '111' corresponds to candidate cell 7.

[0226] It can be seen that before and after the handover, the cells corresponding to the first field with a value of '000' and the first field with a value of '010' are swapped, where '000' is the first value and '010' is the second value.

[0227] Based on this, the updated first rule can be determined according to the correspondence of the first field of the second value, that is, the updated first rule is related to the correspondence of the first field of the second value. The first field of the second value corresponds to the corresponding cell (second cell) which becomes the new service cell accessed by the terminal device after switching. The cell will correspond to the first field of the first value; the service cell (first cell) originally accessed by the terminal device will become a candidate cell and correspond to the first field of the second value. In this case, the fifth value is the same as the second value. For example, both are '010'.

[0228] Optionally, the fifth value is different from the second value.

[0229] In the first case, after the terminal device switches from the first cell to the second cell, the value of the first field corresponding to the first cell may be defaulted to the maximum value. That is, after the terminal device switches, the first field corresponding to the first cell has the maximum value.

[0230] For example, as shown in FIG5 , a correspondence between the value of the first field and the cell before and after the terminal device is switched is shown.

[0231] Before switching, the first field value of '000' corresponds to the original serving cell, the first field value of '001' corresponds to candidate cell 1, the first field value of '010' corresponds to candidate cell 2, the first field value of '011' corresponds to candidate cell 3, the first field value of '100' corresponds to candidate cell 4, the first field value of '101' corresponds to candidate cell 5, the first field value of '110' corresponds to candidate cell 6, and the first field value of '111' corresponds to candidate cell 7.

[0232] After switching to candidate cell 2, the first field with a value of '000' corresponds to the new service cell (candidate cell 2), the first field with a value of '001' corresponds to candidate cell 1, the first field with a value of '010' corresponds to candidate cell 3, the first field with a value of '011' corresponds to candidate cell 4, the first field with a value of '100' corresponds to candidate cell 5, the first field with a value of '101' corresponds to candidate cell 6, the first field with a value of '110' corresponds to candidate cell 7, and the first field with a value of '111' corresponds to the original service cell.

[0233] It can be seen that when the terminal device switches from the original serving cell to candidate cell 2, candidate cell 2 corresponds to the first field with a value of '000', and the original serving cell corresponds to the first field with a value of '111'. The value '111' is the maximum value of the first field. It can also be understood that Figure 5 shows a corresponding order between the first field values ​​and the cells. After the terminal device switches, the original serving cell can be arranged at the end of the corresponding order by default.

[0234] Based on this, the updated first rule can be determined according to the first order. The first order can be understood as the corresponding order of the first field and the cell logical identifier from small to large before the switch as shown in Figure 5. Since the original service cell corresponds to the last bit of the first order after the terminal device switches, the values ​​of the first fields corresponding to other candidate cells may also change accordingly. For example, before the switch, candidate cell 7 corresponds to the first field with a value of '111', and after the switch, candidate cell 7 corresponds to the first field with a value of '110'. It can be seen that in the first case, the fifth value is different from the second value. For example, the second value is '010' and the fifth value is '111'.

[0235] Illustratively, the first order may be an initial default order, or an order predefined according to certain rules.

[0236] In the second case, after the terminal device switches from the first cell to the second cell, the first rule is determined according to the order of the candidate cells configured with random access resource configurations.

[0237] It should be noted that the new candidate cell containing RACH resources may be the original serving cell. The order of the candidate cells configured with random access resources can be determined from the smallest to the largest logical identifiers of the candidate cells configured with random access resources.

[0238] For example, according to the list of candidate cells containing RACH resources in the LTM configuration (the logical identifiers of the candidate cells configured with random access resources are in ascending order), mapped to the first field with different values, the following is obtained:

[0239] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538, corresponding to '00'

[0240] LTM-candidate Cell ID = 1, corresponding to Physical cell ID = 1002, corresponding to '01'

[0241] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123, corresponding to '10'

[0242] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 736, corresponding to '11'

[0243] The original serving cell 538 of the terminal device corresponds to the first field with a value of '00', and the terminal device can switch from the original serving cell 538 to the new serving cell 123. The new serving cell 123 corresponds to the first field with a value of '10' before switching.

[0244] After the terminal device switches from the original serving cell 538 to the new serving cell 123, the correspondence between the value of the first field and the cell can be updated as follows:

[0245] LTM-candidate Cell ID = 2, corresponding to Physical cell ID = 123, corresponding to '00'

[0246] LTM-candidate Cell ID = 0, corresponding to Physical cell ID = 538, corresponding to '01'

[0247] LTM-candidate Cell ID = 1, corresponding to Physical cell ID = 1002, corresponding to '10'

[0248] LTM-candidate Cell ID = 6, corresponding to Physical cell ID = 736, corresponding to '11'

[0249] As can be seen, the new serving cell will be associated with the first field, which has the minimum value of '00'. The original serving cell 538 can be included in the LTM configuration as a new candidate cell with RACH resources. Aside from the new serving cell 123, the order of the other candidate cells with RACH resource configurations in the LTM configuration is: candidate cell 538 for LTM-candidate Cell ID = 0, candidate cell 1002 for LTM-candidate Cell ID = 1, and candidate cell 736 for LTM-candidate Cell ID = 6. In the second case, the first rule is updated based on the order of the candidate cells with random access resource configurations. Based on this, the order of the candidate cells' random access resource configurations is candidate cell 538, candidate cell 1002, and candidate cell 736, and the corresponding first field values ​​are, from smallest to largest, '01', '10', and '11'.

[0250] Therefore, in the second case, the fifth value is different from the second value. For example, the second value is '10' and the fifth value is '01'.

[0251] In a third case, after the terminal device switches from the first cell to the second cell, the first rule is determined according to the order of the identifiers of the candidate cells, where the identifiers of the candidate cells can be understood as physical identifiers of the candidate cells.

[0252] For example, the correspondence between the first field with different values ​​before the terminal device switches and the cell is as follows:

[0253] Physical cell ID = 123, corresponding to '00'

[0254] Physical cell ID = 538, corresponding to '01'

[0255] Physical cell ID = 736, corresponding to '10'

[0256] Physical cell ID = 1002, corresponding to '11'

[0257] The original serving cell 123 of the terminal device corresponds to the first field with a value of '00', and the terminal device can switch from the original serving cell 123 to the new serving cell 1002. The new serving cell 1002 corresponds to the first field with a value of '11' before switching.

[0258] After the terminal device switches from the original serving cell 123 to the new serving cell 1002, the correspondence between the value of the first field and the cell can be updated as follows:

[0259] Physical cell ID = 1002, corresponding to '00'

[0260] Physical cell ID = 123, corresponding to '01'

[0261] Physical cell ID = 538, corresponding to '10'

[0262] Physical cell ID = 736, corresponding to '11'

[0263] It can be seen that the new service cell 1002 will correspond to the first field with the minimum value of '00', and the original service cell 123 will correspond to the first field with the value of '01' in the order of the candidate cell physical identifiers (for example, the candidate cell physical identifiers are cell 123, cell 538, and cell 736 in ascending order).

[0264] Therefore, in the third case, the fifth value is different from the second value. For example, the second value is '11' and the fifth value is '01'.

[0265] In summary, when a terminal device switches between different cells, the first rule can be dynamically updated based on the order of candidate cells configured with random access resource configurations, the correspondence between the first order and the second value of the first field, the order of the candidate cell identifiers, etc. The random access resource configuration of the original serving cell accessed by the terminal device also belongs to the random access resource configuration of the candidate cell, allowing the terminal device to flexibly switch back and forth between different candidate cells.

[0266] In addition, in another implementation, the first information may further include a second field. The second field is used to indicate whether the terminal device triggers sending a random access request message 1 (preamble) to the first cell. The second field may be a single bit added to the first information. This single bit may be used to control whether the terminal device triggers access to the currently serving cell.

[0267] In an embodiment of the present application, a terminal device receives first information from a first network device in a first cell, where the first information includes a first field, which is used to indicate a candidate cell. The first information also includes a second field, which is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell; the terminal device determines the first cell or the second cell based on the first information and the first rule, where the first cell is the service cell currently accessed by the terminal device, the second cell is the candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell.

[0268] Exemplarily, as shown in FIG6 , a schematic diagram of the field structure of the first information is shown. It includes a synchronization signal block index (SSB index), a mask index (physical random access channel mask index, PRACH Mask index), a preamble index (random access preamble index), a cell identifier (cell indicator), a random access request retransmission identifier (PRACH retransmission indicator) and a serving cell random access identifier (serving cell RACH flag). The first field is the cell indicator shown in FIG6 , the second field is the serving cell RACH flag shown in FIG6 , and the random access request retransmission identifier is used to indicate that the terminal device triggers the sending of the random access request message 1 this time, including the initial transmission or retransmission.

[0269] Optionally, in the RRC configuration DCI format, the second field can be selected to be turned on or off.

[0270] When the second field takes the sixth value, the first field is a padding field, and the terminal device can determine to send a random access request message 1 to the first cell based on the second field in the first information.

[0271] Exemplarily, when the sixth value is 1, the second field is used to indicate that the terminal device can trigger random access to the currently accessed service cell (first cell). At this time, the value of the first field can be regarded as meaningless, and the terminal device can ignore the first field, or regard the first field as a filler bit. The PDCCH used to transmit the first information is only used to indicate the RACH of the currently accessed service cell (first cell), that is, the SSB index shown in Figure 6 is the SSB index of the currently accessed service cell, and the PRACH resources are the PRACH resources of the currently accessed service cell.

[0272] When the second field takes the seventh value, before the terminal device determines the second cell according to the first information and the first rule, the terminal device can determine not to send the random access request message 1 to the first cell according to the second field in the first information.

[0273] Exemplarily, when the seventh value is 0, the second field is used to indicate that the terminal device cannot trigger random access to the currently accessed serving cell (first cell). At this time, the currently accessed serving cell does not belong to the candidate cell, and the PDCCH used to transmit the first information is only used to indicate the RACH of the candidate cell. The value of the first field corresponds to the candidate cell containing the RACH.

[0274] The corresponding relationship between the value of the first field and the candidate cells containing RACH can be determined according to the order of random access resource configuration of the candidate cells, for example, as described in the first method above, which will not be repeated here.

[0275] Alternatively, the value of the first field is mapped to the physical identifier of the candidate cell in order from large to small, for example, the corresponding relationship described in the third case above, which will not be repeated here. If the mapping relationship includes the currently accessed service cell, the value of the first field of the currently accessed service cell (for example, the first cell) is invalid. After the terminal device switches from the first cell to other candidate cells, the first cell can be understood as a candidate cell, and the value of the first field corresponding to the first cell is valid.

[0276] Based on the above solution, the terminal device can be displayed and instructed to switch to a candidate cell or trigger access to the current service cell through the second field in the first information, so that the terminal device can flexibly switch back and forth between different cells.

[0277] It should be understood that in the embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0278] It is understood that in each of the above method embodiments, the method implemented by the terminal device can also be implemented by a component (such as a chip or circuit) that can be used in the terminal, and the method implemented by the network device can also be implemented by a component (such as a chip or circuit) that can be used in the network device. Above, the method of the embodiment of the present application is described in detail in conjunction with Figures 2 to 6. The following describes the communication device of the embodiment of the present application in conjunction with Figures 7 to 10.

[0279] FIG7 is a schematic structural diagram of a communication device provided in an embodiment of the present application. The communication device may include: a processing unit 710 and a transceiver unit 720 .

[0280] The communication device 700 provided in the present application may correspond to the process executed by the terminal device in the method embodiments of Figures 2 to 6 above. The functions of the various units / modules in the communication device may refer to the description above, and the detailed description is appropriately omitted here.

[0281] It should be understood that the communication device shown in FIG. 7 may be a terminal device, and may also be applicable to a chip or integrated circuit in the terminal device.

[0282] Taking a terminal device as an example, Figure 8 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. For ease of understanding and illustration, Figure 8 uses a mobile phone as an example. Figure 8 only illustrates the main components of the terminal device. As shown in Figure 8, terminal device 800 includes a processor, memory, control circuitry, and an antenna. Optionally, the terminal device may also include input / output devices. It should be understood that the control circuitry can be located within the processor or independently outside the processor, and the embodiments of the present application are not limited to this. The processor is primarily responsible for processing communication protocols and communication data, controlling the entire terminal device, executing software programs, and processing software program data, for example, to support the terminal device in performing the actions described in the above method embodiments. The memory is primarily responsible for storing software programs and data. The control circuit is primarily responsible for converting baseband signals into radio frequency signals and processing radio frequency signals. The control circuit and antenna together can also be referred to as a transceiver, primarily responsible for transmitting and receiving radio frequency signals in the form of electromagnetic waves. Input / output devices, such as a touch screen, display, and keyboard, are primarily responsible for receiving user input and outputting data to the user.

[0283] When the terminal device is powered on, the processor reads the software program stored in the storage unit, interprets and executes the program's instructions, and processes the program's data. When data needs to be transmitted wirelessly, the processor performs baseband processing on the data to be transmitted and outputs the baseband signal to the RF circuit. The RF circuit then performs RF processing on the baseband signal and transmits it via the antenna as electromagnetic waves. When data is sent to the terminal device, the RF circuit receives the RF signal via the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes it.

[0284] Those skilled in the art will appreciate that, for ease of explanation, FIG8 shows only one memory and processor. In an actual terminal device, multiple processors and memories may exist. Memory may also be referred to as a storage medium or storage device, etc., and this embodiment of the application does not limit this. It should be understood that the memory may be integrated into the processor or located outside the processor and exist independently, and this embodiment of the application is not limited to this.

[0285] As an optional implementation, the processor may include a baseband processor and a central processing unit (CPU). The baseband processor is primarily responsible for processing communication protocols and communication data, while the CPU is primarily responsible for controlling the entire terminal device, executing software programs, and processing data from software programs. The processor in Figure 8 may integrate the functions of both the baseband processor and the CPU. Those skilled in the art will appreciate that the baseband processor and the CPU may also be independent processors interconnected via a bus or other technology. Those skilled in the art will appreciate that a terminal device may include multiple baseband processors to accommodate different network standards, multiple CPUs to enhance its processing capabilities, and that the various components of the terminal device may be connected via various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The CPU may also be referred to as a central processing circuit or a central processing chip. The functionality for processing communication protocols and communication data may be built into the processor or stored as a software program in a storage unit, with the processor executing the software program to implement the baseband processing functionality.

[0286] In the embodiments of the present application, the antenna and control circuit with transceiver functions can be considered as the transceiver unit 801 of the terminal device 800, for example, for supporting the terminal device in performing the transceiver functions performed by the terminal device in the implementation of the method of Figures 2 to 6. The processor with processing functions can be considered as the processing unit 802 of the terminal device 800, which corresponds to the processing unit 710 in Figure 7. As shown in Figure 8, the terminal device 800 includes a transceiver unit 801 and a processing unit 802. The transceiver unit can also be referred to as a transceiver, a transceiver, a transceiver device, etc., and the transceiver unit corresponds to the transceiver unit 720 in Figure 7. Optionally, the device used to implement the receiving function in the transceiver unit 801 can be considered as the receiving unit, and the device used to implement the transmitting function in the transceiver unit 801 can be considered as the transmitting unit. That is, the transceiver unit 801 includes a receiving unit and a transmitting unit. The receiving unit can also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit can be referred to as a transmitter, a transmitter, or a transmitting circuit, etc. It is understood that the transceiver unit can also be an interface circuit.

[0287] The processing unit 802 may be configured to execute instructions stored in the memory to control the transceiver unit 801 to receive and / or transmit signals, thereby completing the functions of the terminal device in the above-described method embodiment. As an implementation method, the functions of the transceiver unit 801 may be implemented using a transceiver circuit or a dedicated transceiver chip.

[0288] It should be understood that the terminal device 800 shown in FIG8 is capable of implementing the various processes related to the terminal device in the method embodiments of FIG2 through FIG6 . The operations and / or functions of the various modules in the terminal device 800 are respectively for implementing the corresponding processes in the aforementioned method embodiments. For details, please refer to the description of the aforementioned method embodiments; to avoid repetition, detailed descriptions are omitted here.

[0289] FIG9 is a schematic structural diagram of a communication device provided in an embodiment of the present application. The device 900 may include a processing unit 910 and a transceiver unit 920 .

[0290] The communication device 900 provided in the present application may correspond to the process executed by the first network device in the method embodiments of Figures 2 to 6 above. The functions of the various units / modules in the communication device may refer to the description above, and the detailed description is appropriately omitted here.

[0291] It should be understood that the communication device described in FIG. 9 may be a network-side device, or may be a chip or integrated circuit that can be used in a network device.

[0292] It should be understood that the network side device can represent any network device that communicates with the terminal device, or it can represent the whole composed of multiple network devices that communicate with the terminal device. The embodiments of the present application are not limited to this.

[0293] The network device 1000 may include one or more radio frequency units, such as a remote radio unit (RRU) 1010 and one or more baseband units (BBU) 1020 (also referred to as digital units, DUs). The RRU may be referred to as a transceiver unit 1010, corresponding to the transceiver unit 920 in FIG9 . Optionally, the transceiver unit may also be referred to as a transceiver, a transceiver circuit, or a transceiver, etc., and may include at least one antenna 1011 and a radio frequency unit 1012. The RRU portion is primarily used for transmitting and receiving radio frequency signals and converting radio frequency signals into baseband signals. The BBU portion is primarily used for baseband processing, controlling the base station, etc. The RRU and BBU may be physically located together or physically separated, i.e., a distributed base station. It is understood that the transceiver unit may also be an interface circuit.

[0294] The BBU 1020 is the control center of the base station, which may also be referred to as the processing unit 1020 , which may correspond to the processing unit 910 in FIG. 9 , and is mainly used to complete baseband processing functions.

[0295] In one example, the BBU 1020 may be composed of one or more single boards, and the multiple single boards may jointly support a wireless access network of a single access standard (such as an LTE network), or may separately support wireless access networks of different access standards (such as an LTE network, a 5G network, or other networks). The BBU 1020 also includes a memory 1021 and a processor 1022. The memory 1021 is used to store necessary instructions and data. The processor 1022 is used to control the base station to perform necessary actions. It should be understood that the memory may be integrated into the processor or may be located outside the processor and exist independently, and the embodiments of the present application are not limited to this. The memory 1021 and the processor 1022 may serve one or more single boards. That is, a memory and a processor may be separately set on each single board. Alternatively, multiple single boards may share the same memory and processor. In addition, necessary circuits may also be provided on each single board.

[0296] It should be understood that the network device 1000 shown in FIG10 is capable of implementing the various processes related to the network device in the method embodiments of FIG2 through FIG6 . The operations and / or functions of the various modules in network device 1000 are respectively for implementing the corresponding processes in the aforementioned method embodiments. For details, please refer to the description of the aforementioned method embodiments; to avoid repetition, detailed descriptions are omitted here.

[0297] An embodiment of the present application further provides a processing device, including a processor and an interface; the processor is used to execute the communication method in any of the above method embodiments.

[0298] It should be understood that the processing device may be a chip. For example, the processing device may be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0299] During implementation, each step of the above method can be completed by an integrated logic circuit of the hardware in the processor or by instructions in the form of software. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0300] It is understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct Rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0301] An embodiment of the present application also provides a communication system, which includes the aforementioned network device and terminal device.

[0302] An embodiment of the present application further provides a computer-readable medium having a computer program stored thereon, which implements the method in any of the above method embodiments when the computer program is executed by a computer.

[0303] An embodiment of the present application further provides a computer program product, which, when executed by a computer, implements the method in any of the above method embodiments.

[0304] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0305] The network devices in the above-mentioned various apparatus embodiments completely correspond to the network devices or terminal devices in the terminal devices and method embodiments, and the corresponding steps are performed by the corresponding modules or units. For example, the sending module (transmitter) performs the sending steps in the method embodiment, and the receiving module (receiver) performs the receiving steps in the method embodiment. Other steps except sending and receiving can be performed by the processing module (processor). The functions of specific modules can refer to the corresponding method embodiments. The sending module and the receiving module can form a transceiver module, and the transmitter and the receiver can form a transceiver to jointly realize the transceiver function; there can be one or more processors.

[0306] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0307] As used in this specification, the terms "component," "module," "system," and the like are used to represent computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. By way of illustration, both an application running on a computing device and a computing device can be a component. One or more components can reside in a process and / or an execution thread, and a component can be located on a computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable media having various data structures stored thereon. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component on a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0308] Those skilled in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0309] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0310] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0311] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0312] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0313] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: include: Receiving first information from a first network device, where a first cell belongs to the first network device, where the first cell is a serving cell currently accessed by a terminal device, and where the first information includes a first field, where the first field is used to indicate a candidate cell, or where the first field is used to indicate the candidate cell and the serving cell currently accessed by the terminal device; The first cell or the second cell is determined according to the first information and the first rule, the second cell belongs to the candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

2. The method according to claim 1, characterized in that The method further comprises: According to the first information and the first rule, a random access request message 1 is sent to the first cell or the second cell.

3. The method according to claim 1 or 2, characterized in that: The first cell is a cell configured with random access resource configuration, and the first rule includes: The first field having a first value corresponds to the first cell, and the first fields having other values ​​correspond to different candidate cells; The first information includes a first field with a second value.

4. The method according to claim 3, characterized in that The initiating random access to the first cell or the second cell according to the first information and the first rule includes: According to the first field of the first value and the first rule, a random access request message 1 is sent to the first cell.

5. The method according to claim 3, characterized in that: The initiating random access to the first cell or the second cell according to the first information and the first rule includes: According to the first field with other values ​​and the first rule, a random access request message 1 is sent to different candidate cells.

6. The method according to any one of claims 1 to 5, characterized in that The first cell belongs to the candidate cell, the second cell is the serving cell after the terminal device is switched, and the first rule is: The first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; The first rule is determined according to the order of candidate cells configured with random access resource configurations.

7. The method according to claim 6, characterized in that The first field of the second value corresponds to the second cell, wherein the fourth value is a minimum value, and the second value is different from the fourth value.

8. The method according to any one of claims 1 to 5, characterized in that The first cell belongs to the candidate cell, the second cell is the serving cell after the terminal device is switched, and the first rule is: The first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

9. The method according to claim 8, characterized in that The first rule is related to one of the following: The order of candidate cells configured with random access resource configuration, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

10. The method according to claim 9, characterized in that The order of the candidate cells configured with random access resource configuration is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

11. The method according to any one of claims 1 to 10, characterized in that When the first field of the first value corresponds to a service cell currently accessed by the terminal device, or corresponds to a service cell after the terminal device is switched, the first value of the first field corresponding to the service cell is a minimum value.

12. The method according to claim 11, characterized in that The first field of the minimum value corresponds to the second cell, and the fifth value and the third value are determined according to the order of the candidate cells configured with random access resource configurations.

13. The method according to claim 1, characterized in that The first information includes a second field, and the second field is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell.

14. The method according to claim 13, characterized in that When the second field takes the sixth value, the first field is a padding field. The determining the second cell according to the first information and the first rule includes: Determine, according to the second field in the first information, that the random access request message 1 is sent to the first cell.

15. The method according to claim 13, characterized in that When the value of the second field is the seventh value, before determining the second cell according to the first information and the first rule, the method further includes: Determine not to send the random access request message 1 to the first cell according to the second field in the first information.

16. The method according to any one of claims 1 to 15, characterized in that The first field is a cell indicator field.

17. The method according to any one of claims 1 to 16, characterized in that The number of bits of the first field is N, where N is the result obtained by calculating the logarithm of (C+1) with base 2 and then rounding up to an integer, and C represents the number of candidate cells configured with random access resources.

18. A communication method, characterized in that: include: The first network device sends first information to the terminal device, where the first information is used to instruct the terminal device to determine the first cell or the second cell according to the first rule; Among them, the first cell belongs to the first network device, the first cell is the service cell currently accessed by the terminal device, the first information includes a first field, and the first field is used to indicate a candidate cell; or the first field is used to indicate the candidate cell and the service cell currently accessed by the terminal device, the second cell belongs to the candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

19. The method according to claim 18, characterized in that The first cell is a cell configured with random access resource configuration, and the first rule includes: The first field having a first value corresponds to the first cell, and the first fields having other values ​​correspond to different candidate cells; The first information includes a first field with a second value.

20. The method according to claim 18 or 19, characterized in that The first cell belongs to the candidate cell, the second cell is the serving cell after the terminal device is switched, and the first rule is: The first field of the third value corresponds to the first cell, and the first field of the fourth value corresponds to the second cell; The first rule is determined according to the order of candidate cells configured with random access resource configurations.

21. The method according to claim 20, characterized in that The first field of the second value corresponds to the second cell, wherein the fourth value is a minimum value, and the second value is different from the fourth value.

22. The method according to claim 18 or 19, characterized in that The first cell belongs to the candidate cell, the second cell is the serving cell after the terminal device is switched, and the first rule is: The first field of the first value corresponds to the second cell, and the first field of the fifth value corresponds to the first cell.

23. The method according to claim 22, characterized in that The first rule is related to one of the following: The order of candidate cells configured with random access resource configuration, the first order, the correspondence between the first field of the second value, and the order of the identifiers of the candidate cells.

24. The method according to claim 23, characterized in that The order of the candidate cells configured with random access resource configuration is determined from small to large according to the logical identifiers of the candidate cells configured with random access resources.

25. The method according to any one of claims 18 to 24, characterized in that When the first field of the first value corresponds to a service cell currently accessed by the terminal device, or corresponds to a service cell after the terminal device is switched, the first value of the service cell corresponding to the first field is a minimum value.

26. The method according to claim 25, characterized in that The first field of the minimum value corresponds to the second cell, and the fifth value and the third value are determined according to the order of the candidate cells configured with random access resource configurations.

27. The method according to claim 18, characterized in that The first information includes a second field, and the second field is used to indicate whether the terminal device triggers sending a random access request message 1 to the first cell.

28. The method according to claim 27, characterized in that When the value of the second field is the sixth value, the first field is a padding field.

29. The method according to any one of claims 18 to 28, characterized in that The first field is a cell indicator field.

30. The method according to any one of claims 18 to 29, characterized in that The number of bits of the first field is N, where N is the result obtained by calculating the logarithm of (C+1) with base 2 and then rounding up to an integer, and C represents the number of candidate cells configured with random access resources.

31. A communication device, characterized in that: include: The processor is used for storing a computer program, and the processor is used for running the computer program so that the communication device performs the method according to any one of claims 1 to 17.

32. A communication device, characterized in that: include: The processor is used for storing a computer program, and the processor is used for running the computer program so that the communication device performs the method according to any one of claims 18 to 30.

33. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a computer, the computer is caused to implement the method according to any one of claims 1 to 17 or 18 to 30.

34. A computer program product comprising instructions, characterized in that When the computer program product is run on a computer, the computer is caused to perform the method according to any one of claims 1 to 17 or 18 to 30.

35. A chip, characterized in that: The chip includes a processor and a data interface, and the processor reads instructions stored in a memory through the data interface to execute the method as described in any one of claims 1 to 17 or 18 to 30.

36. A communication device, characterized in that: include: A receiving module: receiving first information from a first network device, where a first cell belongs to the first network device, where the first cell is a serving cell currently accessed by the terminal device, and where the first information includes a first field, where the first field is used to indicate a candidate cell, or where the first field is used to indicate the candidate cell and the serving cell currently accessed by the terminal device; Processing module; Used to determine the first cell or the second cell based on the first information and the first rule, the second cell belongs to the candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

37. A communication device, characterized in that: include: A sending module: used to send first information to a terminal device, where the first information is used to instruct the terminal device to determine a first cell or a second cell according to a first rule; Among them, the first cell belongs to a first network device, the first cell is a service cell currently accessed by the terminal device, the first information includes a first field, and the first field is used to indicate a candidate cell; or the first field is used to indicate the candidate cell and the service cell currently accessed by the terminal device, the second cell belongs to the candidate cell, and the first rule is used to indicate the correspondence between the first field and the candidate cell and the correspondence between the first field and the service cell currently accessed by the terminal device.

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