CN113873607B

CN113873607B - Cell switching method and device

Info

Publication number: CN113873607B
Application number: CN202111108429.9A
Authority: CN
Inventors: 杨星; 江小威
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2018-09-03
Filing date: 2018-09-03
Publication date: 2023-10-31
Anticipated expiration: 2038-09-03
Also published as: CN109196909A; WO2020047696A1; CN109196909B; CN113873607A

Abstract

The disclosure provides a cell switching method and device, wherein the method comprises the following steps: determining a second alternative base station if the request to switch from the current cell to the cell covered by the first alternative base station fails; transmitting a cell reconfiguration complete message to the second alternative base station; and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to a cell covered by the second alternative base station. In the method, the terminal can perform cell switching again after cell switching failure, so that larger time delay caused by cell reconstruction is avoided, and the performance of the terminal is improved.

Description

Cell switching method and device

Statement of divisional application

The application is based on the application number 201880001861.8 and the application date 2018, 09 and 03, and creates a divisional application of a Chinese application patent application named as a cell switching method and a cell switching device.

Technical Field

The present disclosure relates to the field of communications, and in particular, to a cell handover method and apparatus.

Background

In the related art, a procedure of performing cell handover by a terminal is shown in fig. 1.

And the terminal reports the measurement report to a source base station which is accessed by the terminal currently, and the source base station determines whether the terminal needs to perform cell switching according to the measurement report. If the source base station determines that the terminal needs to perform cell switching, the source base station sends a switching request to a plurality of alternative base stations, and after the plurality of alternative base stations are confirmed, the source base station sends a cell switching command message to the terminal, wherein the cell switching command message carries configuration information of target cells respectively covered by the plurality of alternative base stations.

After receiving the cell switching command message, the terminal starts a timer, generates a reconfiguration complete message by the RRC (Radio Resource Control ) layer, sends the reconfiguration complete message to the PDCP (Packet Data Convergence Protocol ) layer, triggers the MAC (Media Access Control, medium access control) to initiate a random access procedure to the target cell, stops the timer after the random access is successful, and then continues the subsequent switching procedure.

If the random access process is unsuccessful when the timer is overtime, that is, the terminal does not receive the scheduling information of the PDCCH (Physical Downlink Control Channel ) corresponding to the terminal, which is sent by the target cell, the terminal considers that the handover fails, and at this time, the terminal initiates a cell reestablishment process. And larger time delay is generated when the cell reconstruction is performed.

Disclosure of Invention

To overcome the problems in the related art, embodiments of the present disclosure provide a cell handover method and apparatus.

According to a first aspect of embodiments of the present disclosure, there is provided a cell handover method, the method being used for a terminal, the method comprising:

determining a second alternative base station if the request to switch from the current cell to the cell covered by the first alternative base station fails;

Transmitting a cell reconfiguration complete message to the second alternative base station;

and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to a cell covered by the second alternative base station.

Optionally, if the handover from the current cell request to the cell covered by the first alternative base station fails, the method further comprises:

discarding the data unit corresponding to the packet data convergence protocol PDCP layer which is currently stored, and subtracting one from the transmission sequence number of the data unit corresponding to the PDCP layer.

Optionally, the method further comprises:

transmitting a measurement report to a source base station which is accessed currently, wherein the measurement report is used for the source base station to determine whether the terminal needs to perform cell switching;

if a cell switching command message carrying a plurality of alternative base stations is received, which is returned by the source base station, one alternative base station, of the plurality of alternative base stations, of which the reference signal quality meets the preset cell selection condition is used as the first alternative base station;

and requesting to switch to the cell covered by the first alternative base station from the current cell.

Optionally, the determining the second alternative base station includes:

And taking one of the plurality of alternative base stations which does not receive the cell reconfiguration completion message sent by the terminal and the reference signal quality meets the preset cell selection condition as the second alternative base station.

Optionally, the method further comprises:

and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, repeating the step of determining the second alternative base station, and then sending a cell reconfiguration complete message to the second alternative base station until the cell is successfully switched to the cell covered by the second alternative base station.

Optionally, the cell switching command message carries a switching parameter; the switching parameters include any one of a switching timer parameter and a switching counter parameter;

the switching timer parameter is used for indicating the effective duration of the terminal for cell switching;

the switching counter parameter is used for indicating the maximum value of the accumulated times of the terminal for carrying out cell switching.

Optionally, the method further comprises:

and if the time length of the terminal for cell switching reaches the effective time length indicated by the switching timer parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, starting a cell reconstruction process.

Optionally, the method further comprises:

and if the accumulated times of cell switching by the terminal reaches the maximum value indicated by the switching counter parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, starting a cell reestablishment flow.

According to a second aspect of embodiments of the present disclosure, there is provided a cell switching apparatus for a terminal, the apparatus comprising:

a first determining module configured to determine a second alternative base station if a handover from a current cell request to a cell covered by the first alternative base station fails;

a first sending module configured to send a cell reconfiguration complete message to the second alternative base station;

and the first switching module is configured to switch to a cell covered by the second alternative base station if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received.

Optionally, the apparatus further comprises:

and the execution module is configured to discard the data unit corresponding to the packet data convergence protocol PDCP layer which is currently stored, and reduce the transmission sequence number of the data unit corresponding to the PDCP layer by one.

Optionally, the apparatus further comprises:

a second sending module configured to send a measurement report to a source base station currently accessed, where the measurement report is used by the source base station to determine whether the terminal needs to perform cell handover;

the second determining module is configured to take one candidate base station, which satisfies a preset cell selection condition, of the plurality of candidate base stations as the first candidate base station if a cell switching command message carrying the plurality of candidate base stations returned by the source base station is received;

and a second switching module configured to request switching from the current cell to the cell covered by the first alternative base station.

Optionally, the first determining module includes:

and the determining submodule is configured to take one of the plurality of alternative base stations which does not receive the cell reconfiguration complete message sent by the terminal and the reference signal quality of which meets the preset cell selection condition as the second alternative base station.

Optionally, the apparatus further comprises:

and the control module is configured to control the first determining module to repeat the determination of the second alternative base station if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, and then control the first transmitting module to transmit a cell reconfiguration complete message to the second alternative base station until the cell covered by the second alternative base station is successfully switched.

Optionally, the apparatus further comprises:

the first starting module is configured to start a cell reestablishment flow if the cell switching duration of the terminal reaches the effective duration indicated by the switching timer parameter and the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal returned by the second alternative base station is not received.

Optionally, the apparatus further comprises:

and the second starting module is configured to start a cell reestablishment flow if the number of times of cell switching performed by the terminal reaches the maximum value indicated by the switching counter parameter and scheduling information of a Physical Downlink Control Channel (PDCCH) corresponding to the terminal returned by the second alternative base station is not received.

According to a third aspect of embodiments of the present disclosure, there is provided a computer readable storage medium storing a computer program for executing the cell handover method according to the first aspect.

According to a fourth aspect of embodiments of the present disclosure, there is provided a cell switching apparatus for a terminal, including:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to:

The technical scheme provided by the embodiment of the disclosure can comprise the following beneficial effects:

in the embodiment of the disclosure, if the terminal fails to switch from the current cell request to the cell covered by the first alternative base station, the terminal may not perform cell reconstruction, but determine a second alternative base station, and send a cell reconfiguration complete message to the second alternative base station; and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to a cell covered by the second alternative base station. Through the process, the terminal can perform cell switching again after the cell switching fails, so that larger time delay caused by cell reconstruction is avoided, and the performance of the terminal is improved.

In the embodiment of the disclosure, after a cell request from a current cell to be switched to a cell covered by a first alternative base station fails, the terminal may discard a data unit corresponding to a PDCP layer of a packet data convergence protocol stored currently, and reduce a transmission sequence number of the data unit corresponding to the PDCP layer by one. The accuracy of the ciphering and integrity protection algorithms of the terminal at the PDCP layer is ensured so that the subsequent terminal can retransmit a transmitting cell reconfiguration complete message to the second alternative base station.

In the embodiment of the disclosure, a terminal can send a measurement report to a source base station, and the source base station determines whether the terminal needs to perform cell switching according to the measurement report. If the terminal receives a cell switching command message carrying a plurality of alternative base stations returned by the source base station, the terminal can select one alternative base station with reference signal quality meeting preset cell selection conditions from the plurality of alternative base stations as a first alternative base station, and then request to switch to a cell covered by the first alternative base station from a current cell. The usability is high.

In the embodiment of the disclosure, when determining the second alternative base station, the terminal may select, from a plurality of alternative base stations provided by the source base station, one alternative base station that does not receive the cell reconfiguration complete message sent by the terminal and that satisfies the preset cell selection condition with reference signal quality as the second alternative base station. In the embodiment of the disclosure, the terminal can determine the second alternative base station when the cell switching is performed again according to the plurality of alternative base stations provided by the source base station, so that the implementation is simple and convenient, and the availability is high.

In the embodiment of the disclosure, if the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the step of determining the second alternative base station is repeated, and a cell reconfiguration complete message is sent to the second alternative base station after that until the terminal is successfully switched to the cell covered by the second alternative base station. In the above embodiment, after the terminal fails to request to switch to the cell covered by the first alternative base station from the current cell, the terminal may request to switch to the second alternative base station, and if the switch fails again, a new second alternative base station may be redetermined, and cell switching may be performed again until the handover is successful in the cell covered by the second alternative base station. And larger time delay caused by cell reconstruction is avoided, and the terminal performance is improved.

In the embodiment of the disclosure, the source base station may carry a handover parameter when returning a handover command message, where the handover parameter may be any one of a handover timer parameter and a handover counter parameter. Optionally, the switching timer parameter is used for indicating the effective duration of the terminal for cell switching; the switching counter parameter is used for indicating the maximum value of the accumulated times of the terminal for carrying out cell switching. The terminal can control the time length of cell switching or control the accumulated times of cell switching according to the switching parameters, so that under the condition that the time length of cell switching is longer or the accumulated times of cell switching are more, the terminal starts a cell reestablishment flow, and the terminal is prevented from causing larger time delay when the terminal performs cell switching for many times. Ensuring normal operation of terminal service.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic diagram illustrating a cell handover scenario in the related art according to an exemplary embodiment.

Fig. 2 is a flow chart illustrating a method of cell handover according to an exemplary embodiment.

Fig. 3 is a flow chart illustrating another cell handover method according to an example embodiment.

Fig. 4 is a flowchart illustrating another cell handover method according to an example embodiment.

Fig. 5 is a flowchart illustrating another cell handover method according to an example embodiment.

Fig. 6 is a flowchart illustrating another cell switching method according to an exemplary embodiment.

Fig. 7 is a flowchart illustrating another cell handover method according to an example embodiment.

Fig. 8 is a flowchart illustrating another cell handover method according to an example embodiment.

Fig. 9 is a block diagram of a cell switching apparatus according to an exemplary embodiment.

Fig. 10 is a block diagram of another cell switching apparatus according to an exemplary embodiment.

Fig. 11 is a block diagram of another cell switching apparatus according to an exemplary embodiment.

Fig. 12 is a block diagram of another cell switching apparatus according to an example embodiment.

Fig. 13 is a block diagram of another cell switching apparatus according to an example embodiment.

Fig. 14 is a block diagram of another cell switching apparatus according to an exemplary embodiment.

Fig. 15 is a block diagram of another cell switching apparatus according to an exemplary embodiment.

Fig. 16 is a schematic diagram of another architecture for a cell switching apparatus according to an exemplary embodiment of the present disclosure.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of the invention as detailed in the accompanying claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if" as used herein may be interpreted as "at … …" or "at … …" or "responsive to a determination", depending on the context.

The embodiment of the disclosure provides a cell switching method which can be used for terminals, such as smart phones, tablet computers, personal digital assistants (Personal Digital Assistant, PDAs) and the like. Referring to fig. 2, fig. 2 is a flowchart illustrating a cell handover method according to an exemplary embodiment, which may include the steps of:

In step 101, if a handover from the current cell to a cell covered by the first alternative base station is requested to fail, determining a second alternative base station;

in step 102, a cell reconfiguration complete message is sent to the second alternative base station;

in step 103, if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to the cell covered by the second alternative base station.

In the above embodiment, if the terminal fails to switch from the current cell to the cell covered by the first alternative base station, it may determine the second alternative base station without performing cell reestablishment, and send a cell reconfiguration complete message to the second alternative base station; and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to a cell covered by the second alternative base station. Through the process, the terminal can perform cell switching again after the cell switching fails, so that larger time delay caused by cell reconstruction is avoided, and the performance of the terminal is improved.

For the step 101, if the terminal receives the cell switching command message carrying multiple alternative base stations sent by the source base station, the terminal determines that cell switching is currently required. Wherein the source base station is a base station covering the current cell. Further, the terminal may determine a first alternative base station among the plurality of alternative base stations. Alternatively, one of the alternative base stations whose reference signal quality satisfies the preset cell selection condition may be used as the first alternative base station.

The reference signal quality may be characterized by at least one of RSRP (Reference Signal Receiving Power, reference signal received power) and RSRQ (reference signal received quality).

In this step, the terminal may send a cell reconfiguration complete message to the first alternative base station according to the related art, and start a timer at the same time. Alternatively, the timer may be a T304 timer used at system handover. If the timer times out, the scheduling information of the PDCCH (Physical Downlink Control Channel ) corresponding to the terminal, returned by the first alternative base station, is not received yet, the terminal determines that the switching from the current cell request to the cell covered by the first alternative base station fails.

The terminal may not perform cell re-establishment at this point but rather determine a second alternative base station. Optionally, in the embodiment of the present disclosure, the terminal may determine a second alternative base station from the multiple alternative base stations returned by the source base station, where the second alternative base station is one alternative base station that does not receive the cell reconfiguration complete message sent by the terminal and the reference signal quality meets a preset cell selection condition in the multiple alternative base stations.

For example, the plurality of alternative base stations includes base station a, base station B, and base station C. The first alternative base station is a base station A, the base station A already receives the cell reconfiguration complete message sent by the terminal, and the base station B and the base station C do not receive the cell reconfiguration complete message sent by the terminal. The terminal may select one of the base stations B and C, which satisfies the preset cell selection condition, as the second alternative base station, assuming that the base station B is the second alternative base station, and use the second alternative base station as the second alternative base station.

If the base station B and the base station C do not receive the cell reconfiguration complete message sent by the terminal and both meet the preset cell selection condition of the reference signal quality, an alternative base station with better reference signal quality can be selected as the second alternative base station.

For the above step 102, after determining the second alternative base station, the terminal may send a cell reconfiguration complete message to the second alternative base station again according to the related art. Meanwhile, the terminal may restart the timer according to the related art. Alternatively, the timer may be a T304 timer used at system handover.

For the step 103, if the terminal receives the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station before the time-out of the T304 timer, the terminal may execute a cell switching process according to the related technology, and switch to the cell covered by the second alternative base station.

In the above embodiment, after the cell switching failure, the terminal can perform the cell switching again, so that a larger time delay caused by cell reconstruction is avoided, and the performance of the terminal is improved.

In an embodiment, referring to fig. 3, fig. 3 is a flowchart of another cell switching method according to the embodiment shown in fig. 2, if a cell switching from a current cell request to a first alternative base station coverage fails, the cell switching method may further include the steps of:

in step 104, discarding the data unit corresponding to the PDCP layer of the packet data convergence protocol currently stored, and subtracting one from the transmission sequence number of the data unit corresponding to the PDCP layer.

In the related art, after receiving a cell handover command message sent by a source base station, a terminal updates an algorithm for ciphering and integrity protection of its PDCP layer and a key, and then, after receiving a reconfiguration complete message generated by an RRC layer, the PDCP layer performs subsequent processing according to a new ciphering and integrity protection algorithm.

The input parameters corresponding to the encryption and integrity protection algorithm comprise: DIRECTION, BEARER and COUNT. Wherein the DIRECTION is used for representing the data transmission DIRECTION; BEARER is used for the radio BEARER identification of the meter terminal; the COUNT is a counter, and is composed of HFN (hyper frame number) and PDCP layer transmission sequence number, and each PDCP layer transmits one PDCP corresponding data unit, the transmission sequence number is incremented by one.

In the embodiment of the disclosure, the transmission sequence number of the data unit corresponding to the PDCP layer has been increased by one due to the failure of the terminal to request to switch to the first alternative base station. In order to ensure that the terminal can initiate a cell reconfiguration complete message to the second alternative base station again, the data unit corresponding to the currently stored packet data convergence protocol PDCP layer can be discarded, and the transmission sequence number of the data unit corresponding to the PDCP layer is decremented by one. Optionally, the data units corresponding to the PDCP layer include PDUs (Protocol Data Unit, protocol data units) and SDUs (service Data Unit, service data units).

The terminal may send a cell reconfiguration complete message to the second alternative base station after performing step 104. And if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switching to a cell covered by the second alternative base station.

In the above embodiment, after the cell request from the current cell to be switched to the cell covered by the first alternative base station fails, the terminal may discard the data unit corresponding to the PDCP layer of the packet data convergence protocol stored currently, and reduce the transmission sequence number of the data unit corresponding to the PDCP layer by one. The accuracy of the ciphering and integrity protection algorithms of the terminal at the PDCP layer is ensured so that the subsequent terminal can send a cell reconfiguration complete message to the second alternative base station again.

In an embodiment, referring to fig. 4, fig. 4 is a flowchart of another cell handover method according to the embodiment shown in fig. 2, the method further comprising:

in step 100-1, a measurement report is sent to a source base station which is accessed currently, wherein the measurement report is used for the source base station to determine whether the terminal needs to perform cell switching;

in this step, the terminal sends a measurement report to the current access source base station according to the related technology, and the source base station can determine whether the terminal needs to perform cell switching according to the measurement report.

In step 100-2, if a cell switching command message carrying a plurality of alternative base stations returned by the source base station is received, taking one alternative base station, of the plurality of alternative base stations, with reference signal quality meeting a preset cell selection condition as the first alternative base station;

in this step, if cell switching is required, the source base station determines a plurality of alternative base stations according to the related technology, and sends a cell switching request to the plurality of alternative base stations, after the plurality of alternative base stations return acknowledgement messages to allow the terminal to perform cell switching, the source base station returns a cell switching command message carrying the plurality of alternative base stations to the terminal, and the terminal can receive according to the related technology.

Further, the terminal may select, from a plurality of candidate base stations provided by the source base station, as the first candidate base station, one candidate base station whose reference signal quality satisfies a preset cell selection condition. Alternatively, the reference signal quality may be characterized by at least one of RSRP and RSRQ.

In step 100-3, a handover is requested from the current cell to a cell covered by the first alternative base station.

In this step, the terminal may send a cell reconfiguration complete message to the first alternative base station, and at the same time, the terminal may start a timer, and optionally, the timer may be a T304 timer used during system handover. If the terminal receives the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the first alternative base station before the timer is overtime, the terminal can continue to execute the cell switching flow according to the related technology and switch to the cell covered by the first alternative base station.

If the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the first alternative base station before the timer is overtime, the terminal fails to switch from the current cell request to the cell covered by the first alternative base station. At this time, the terminal may perform steps 101 to 103 described above, and switch to the cell covered by the second alternative base station.

In the above embodiment, the terminal may send a measurement report to the source base station, and the source base station determines whether the terminal needs to perform cell handover according to the measurement report. If the terminal receives a cell switching command message carrying a plurality of alternative base stations returned by the source base station, the terminal can select one alternative base station with reference signal quality meeting preset cell selection conditions from the plurality of alternative base stations as a first alternative base station, and then request to switch to a cell covered by the first alternative base station from a current cell. The usability is high.

In an embodiment, the determining the second alternative base station in step 101 may include: and taking one of the plurality of alternative base stations which does not receive the cell reconfiguration completion message sent by the terminal and the reference signal quality meets the preset cell selection condition as the second alternative base station.

In the embodiment of the disclosure, the terminal may determine a second alternative base station from the multiple alternative base stations returned by the source base station, where the second alternative base station is one alternative base station that does not receive the cell reconfiguration complete message sent by the terminal and the reference signal quality meets a preset cell selection condition. Alternatively, the reference signal quality may be characterized by at least one of RSRP and RSRQ.

Further, after determining the second alternative base station, the terminal may send a cell reconfiguration complete message to the second alternative base station, and if scheduling information of a physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received, switch to a cell covered by the second alternative base station.

In an embodiment, referring to fig. 5, fig. 5 is a flowchart of another cell switching method according to the embodiment shown in fig. 4, where the cell switching method may further include:

in step 105, if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, repeating the step of determining the second alternative base station, and then sending a cell reconfiguration complete message to the second alternative base station until the handover is successfully performed to the cell covered by the second alternative base station.

In this step, if the terminal sends a cell reconfiguration complete message to the second alternative base station, and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received before the timeout of the T304 timer, the terminal may determine a new second alternative base station again.

According to the above step 101-1, one candidate base station that does not receive the cell reconfiguration complete message sent by the terminal and that satisfies the preset cell selection condition with reference signal quality is selected again from the plurality of candidate base stations as a new second candidate base station.

For example, the plurality of alternative base stations includes base station a, base station B, and base station C. The first alternative base station is a base station A, the base station A already receives the cell reconfiguration complete message sent by the terminal, and the base station B and the base station C do not receive the cell reconfiguration complete message sent by the terminal. The terminal may select one of the base stations B and C, which satisfies the preset cell selection condition, and assume that the base station B is the second base station.

If the terminal sends a cell reconfiguration complete message to the base station B, and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the base station B is not received before the timeout of the T304 timer, the terminal may determine a new second alternative base station again from the multiple alternative base stations, where the base station C may be regarded as the new second alternative base station.

After determining the new second alternative base station, the terminal sends a cell reconfiguration completion message to the new second alternative base station, and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received before the timeout of the T304 timer, the terminal can be switched to the cell covered by the second alternative base station according to the related technology. If the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the new second alternative base station, the above step 101-1 may be repeated again, and then a cell reconfiguration complete message is sent to the second alternative base station until the terminal is successfully switched to the cell covered by the second alternative base station.

In the above embodiment, if the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the step of determining the second alternative base station is repeated, and then a cell reconfiguration complete message is sent to the second alternative base station until the terminal is successfully handed over to the cell covered by the second alternative base station. In the above embodiment, after the terminal fails to request to switch to the cell covered by the first alternative base station from the current cell, the terminal may request to switch to the second alternative base station, and if the switch fails again, a new second alternative base station may be redetermined, and cell switching may be performed again until the handover is successful in the cell covered by the second alternative base station. And larger time delay caused by cell reconstruction is avoided, and the terminal performance is improved.

In an embodiment, if the terminal performs cell switching for a long time or multiple times, a larger delay is also caused, which affects the terminal service. Therefore, in the embodiment of the present disclosure, the source base station may carry the handover parameter in the cell handover command message returned to the terminal. The switching parameters include any one of a switching timer parameter and a switching counter parameter; the switching timer parameter is used for indicating the effective duration of the terminal for cell switching; the switching counter parameter is used for indicating the maximum value of the accumulated times of the terminal for carrying out cell switching.

The terminal can control the time for carrying out cell switching by itself or accumulate the times of carrying out cell switching according to the switching parameters.

In an embodiment, referring to fig. 6, fig. 6 is a flowchart of another cell switching method according to the embodiment shown in fig. 5, where the cell switching method may further include:

in step 106, if the duration of cell switching performed by the terminal reaches the effective duration indicated by the switching timer parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, a cell reestablishment procedure is started.

In this step, when the terminal fails to switch from the current cell to the cell covered by the first alternative base station, the terminal starts a switching timer, and the duration of the switching timer is the effective duration indicated by the switching timer parameter. And the terminal sends a cell reconfiguration completion message to the second alternative base station, and if the switching timer is over, the terminal still does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the terminal can stop cell switching, and the cell reestablishment process is started according to the related technology.

Optionally, the terminal may start the handover timer when requesting to handover from the current cell to the cell covered by the first alternative base station, if the terminal fails to handover from the current cell to the cell covered by the first alternative base station, the terminal sends a cell reconfiguration complete message to the second alternative base station, and when the handover timer is overtime, if the terminal has not received the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the terminal may stop performing cell handover, and start a cell reestablishment procedure according to the related technology.

In an embodiment, referring to fig. 7, fig. 7 is a flowchart of another cell switching method according to the embodiment shown in fig. 5, where the cell switching method may further include:

in step 107, if the number of times of cell switching performed by the terminal reaches the maximum value indicated by the switching counter parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, a cell reestablishment procedure is started.

In this step, after the terminal fails to request to switch from the current cell to the cell covered by the first alternative base station, the terminal starts a switch counter, where the initial value of the switch counter is zero. And adding one to the value of the switching counter every time the terminal sends a cell reconfiguration completion message to the second alternative base station. If the number of times the terminal accumulates to perform cell handover reaches the maximum value indicated by the handover counter parameter, i.e. the number of times the handover counter counts reaches the maximum value,

And the terminal still does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the terminal can stop the cell switching, and the cell reestablishment flow is started according to the related technology.

Alternatively, the terminal may start the handover counter when it requests a handover from the current cell to the cell covered by the first alternative base station, the initial value of the handover counter being zero. If the terminal fails to switch from the current cell request to the cell covered by the first alternative base station, the value of the switch counter is increased by one. And the value of the switching counter is increased by one every time the terminal sends a cell reconfiguration completion message to the second alternative base station. And when the number of times of cell switching in the terminal reaches the maximum value indicated by the switching counter parameter, namely the number of times counted by the switching counter reaches the maximum value, and the terminal still does not receive the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal and returned by the second alternative base station, the terminal can stop cell switching, and the cell reestablishment process is started according to the related technology.

In the above embodiment, the source base station may carry a handover parameter when returning a handover command message, and the handover parameter may be any one of a handover timer parameter and a handover counter parameter. Optionally, the switching timer parameter is used for indicating the effective duration of the terminal for cell switching; the switching counter parameter is used for indicating the maximum value of the accumulated times of the terminal for carrying out cell switching. The terminal can control the time length of cell switching or control the accumulated times of cell switching according to the switching parameters, so that under the condition that the time length of cell switching is longer or the accumulated times of cell switching are more, the terminal starts a cell reestablishment flow, and the terminal is prevented from causing larger time delay when the terminal performs cell switching for many times. Ensuring normal operation of terminal service.

In an embodiment, referring to fig. 8, fig. 8 is a flowchart illustrating another cell switching method according to an embodiment, the cell switching method may include:

in step 201, a terminal sends a measurement report to a source base station which is currently accessed;

the measurement report is used by the source base station to determine whether the terminal needs to perform cell switching.

In step 202, a cell handover command message carrying a plurality of alternative base stations and handover parameters is returned by the source base station to the terminal.

In this step, if the source base station determines that the terminal needs to perform cell switching, the source base station sends a switching request to a plurality of second alternative base stations, and after the second alternative base stations confirm that the second alternative base stations are completed, the source base station sends a cell switching command message to the terminal (not shown in fig. 8), where the cell switching command message carries configuration information of target cells covered by each of the second alternative base stations.

The switching parameters include any one of a switching timer parameter and a switching counter parameter; the switching timer parameter is used for indicating the effective duration of the terminal for cell switching; the switching counter parameter is used for indicating the maximum value of the accumulated times of the terminal for carrying out cell switching.

In step 203, the terminal determines a first alternative base station among a plurality of alternative base stations.

In step 204, the terminal sends a cell reconfiguration complete message to the first alternative base station.

In step 205, after the terminal fails to request handover from the current cell to the cell covered by the first alternative base station, the second alternative base station is determined.

In this step, the terminal uses, as the second alternative base station, one of the plurality of alternative base stations that does not receive the cell reconfiguration complete message sent by the terminal and that satisfies a preset cell selection condition with reference signal quality.

In step 206, the terminal sends a cell reconfiguration complete message to the second alternative base station.

In step 207, if the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the above steps 205 to 206 are repeated.

In step 208, if the terminal receives the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, the terminal is switched to the cell covered by the second alternative base station.

In step 209, if the duration of cell switching by the terminal reaches the effective duration indicated by the switching timer parameter or the number of times of cell switching by the terminal reaches the maximum value indicated by the switching counter parameter, and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, a cell reestablishment procedure is started.

The above embodiments are further illustrated as follows.

In example 1, when a terminal receives a cell handover command message sent by a source base station, the cell handover command message carries a plurality of alternative base stations including a base station a, a base station B and a base station C, and meanwhile, the cell handover command message carries a handover timer parameter T. After the terminal sends a cell reconfiguration completion message to the base station A to perform cell switching failure, the terminal discards the data unit corresponding to the PDCP layer which is currently stored and comprises PDU and SDU, reduces the sending sequence number of the data unit corresponding to the PDCP layer by one, and starts a switching timer, wherein the duration of the switching timer is T.

The terminal measures the base station B and the base station C, and if the reference signal quality of the base station B meets the preset cell selection condition, the terminal sends a cell reconfiguration completion message to the base station B. If the terminal fails the cell handover again, the terminal discards the data unit corresponding to the PDCP layer, including the PDU and the SDU, and decrements the transmission sequence number of the data unit corresponding to the PDCP layer by one.

If the reference signal quality of the base station C meets the preset cell selection condition, the terminal sends a cell reconfiguration completion message to the base station C.

If the handover is successful, the handover timer is stopped. If the switching timer is overtime, the terminal starts the cell reestablishment flow.

In example 2, when the terminal receives a cell handover command message sent by the source base station, the cell handover command message carries a plurality of alternative base stations including a base station a, a base station B and a base station C, and meanwhile, the cell handover command message carries a handover counter parameter CT. After the terminal sends a cell reconfiguration completion message to the base station A to perform cell switching failure, the terminal discards the data unit corresponding to the PDCP layer which is currently stored and comprises PDU and SDU, reduces the sending sequence number of the data unit corresponding to the PDCP layer by one, and adds one to the accumulated times of cell switching by the terminal when each time of cell switching is initiated from zero.

The terminal measures the base station B and the base station C, and if the reference signal quality of the base station B meets the preset cell selection condition, the terminal sends a cell reconfiguration completion message to the base station B. If the terminal fails the cell handover again, the terminal discards the data unit corresponding to the PDCP layer, including the PDU and the SDU, and decrements the transmission sequence number of the data unit corresponding to the PDCP layer by one. And adding one more time for the terminal to perform cell switching.

If the switching is successful, stopping accumulating the times of the terminal for carrying out the cell switching. If the number of times of the terminal for carrying out the cell switching reaches the maximum number of times, the terminal starts a cell reestablishment flow.

In the above embodiment, after the cell switching failure, the terminal can perform the cell switching again, so that a larger time delay caused by cell reconstruction is avoided, and the performance of the terminal is improved. In addition, the terminal can control the time length of cell switching or control the accumulated times of cell switching according to the switching parameters, so that cell reconstruction is performed under the condition that the cell switching time is longer or the accumulated times of cell switching are more, and larger time delay caused by the fact that the terminal performs cell switching for many times is avoided. Ensuring normal operation of terminal service.

In an alternative embodiment, the present disclosure provides a method of determining a cell handover failure. The terminal may determine a cell failure to switch from the current cell to the coverage of the first alternative base station in the following manner:

in step 11, a cell reconfiguration complete message is sent to the first alternative base station, and a timer is started.

The terminal may send a cell reconfiguration complete message to the first alternative base station while starting a timer. Alternatively, the timer may be a T304 timer used at system handover.

In step 12, in response to the timer expiring, a failure to switch from the current cell to a cell covered by a first alternative base station is determined.

And under the condition that the timer is overtime, if the scheduling information of the PDCCH corresponding to the terminal returned by the first alternative base station is not received yet, the terminal determines that the cell requested to be switched to be covered by the first alternative base station from the current cell fails.

In the above embodiment, a timer may be started while the cell reconfiguration complete message is sent to the first alternative base station, and when the timer expires, it is determined that the handover from the current cell to the cell covered by the first alternative base station fails. The method and the device achieve the purpose of determining the cell switching failure, and are high in availability.

In an alternative embodiment, the present disclosure also provides a solution for determining alternative base stations.

The terminal may determine the first alternative base station in the following manner:

in step 21, one of the plurality of alternative base stations, the reference signal quality of which meets the preset cell selection condition, is used as the first alternative base station.

In the embodiment of the disclosure, the terminal may determine, from among a plurality of alternative base stations, one alternative base station whose reference signal quality satisfies a preset cell selection condition, as the first alternative base station.

In the embodiment, the terminal can quickly determine the first alternative base station from the plurality of alternative base stations, so that the implementation is simple and the availability is high.

In an alternative embodiment, the present disclosure also provides a solution for determining alternative base stations. The terminal may determine the second alternative base station in the following manner:

in step 31, in response to a cell failure in switching from the current cell to the coverage of the first alternative base station, one of the plurality of alternative base stations which is not determined as the first alternative base station and whose reference signal quality satisfies a preset cell selection condition is taken as the second alternative base station.

In the embodiment of the disclosure, the terminal may determine a second alternative base station in case of failure of handover from the current cell to the cell covered by the first alternative base station. Specifically, the terminal may take, as the second alternative base station, one of a plurality of alternative base stations which is not determined as the first alternative base station and whose reference signal quality satisfies a preset cell selection condition. That is, when the terminal determines the second alternative base station from the plurality of alternative base stations, it needs to ensure that the second alternative base station is different from the first alternative base station determined previously, and the reference signal quality needs to meet a preset cell selection condition, and the alternative base station is determined as the second alternative base station.

In the above embodiment, the terminal may quickly determine the second alternative base station from the multiple alternative base stations under the condition that the handover from the current cell to the cell covered by the first alternative base station fails, which is simple and convenient to implement and has high availability.

In an alternative embodiment, the present disclosure further provides a scheme for triggering the selection of the first alternative base station. The terminal may trigger the selection of the first alternative base station in the following manner:

in step 41, a measurement report is sent to the currently accessed source base station.

In the embodiment of the disclosure, the measurement report is used by the source base station to determine whether the terminal needs to perform cell switching. The terminal can directly send the measurement report to the current accessed source base station, and the source base station determines whether the terminal needs to perform cell switching according to the measurement report.

In step 42, if a cell handover command message carrying a plurality of alternative base stations returned by the source base station is received, the first alternative base station is selected from the plurality of alternative base stations.

In the embodiment of the disclosure, if the source base station determines that the terminal needs to perform cell switching, the source base station sends a switching request to a plurality of alternative base stations, and after the plurality of alternative base stations confirm that the cell switching command message is sent to the terminal by the source base station, wherein the cell switching command message carries the plurality of alternative base stations. The terminal may select a first alternative base station from the plurality of alternative base stations after receiving the cell handover command message.

In the above embodiment, the terminal may report a measurement report to the source base station, and the source base station determines whether the terminal needs to perform cell handover. Further, if the terminal receives a cell switching command message carrying a plurality of alternative base stations returned by the source base station, the terminal triggers a step of selecting a first alternative base station from the plurality of alternative base stations.

in step 51, one candidate base station, of the plurality of candidate base stations, whose reference signal quality satisfies a preset cell selection condition in the cell handover command message carrying the plurality of candidate base stations returned by the source base station is determined as the second candidate base station.

In the embodiment of the disclosure, the source base station currently accessed by the terminal can send the cell switching command message carrying a plurality of alternative base stations to the terminal. After the terminal receives the signal, one alternative base station with the reference signal quality meeting the preset cell selection condition can be determined in a plurality of alternative base stations, and the alternative base station is determined to be a second alternative base station.

In the above embodiment, the second alternative base station may be determined based on the cell handover command message sent by the source base station to which the terminal is currently connected, which is simple to implement and has high availability.

Corresponding to the foregoing embodiment of the application function implementation method, the present disclosure further provides an embodiment of an application function implementation device and a corresponding terminal.

Referring to fig. 9, fig. 9 is a block diagram of a cell switching apparatus for a terminal according to an exemplary embodiment, the apparatus comprising:

a first determining module 310 configured to determine a second alternative base station if a handover from a current cell request to a cell covered by the first alternative base station fails;

a first sending module 320 configured to send a cell reconfiguration complete message to the second alternative base station;

and the first switching module 330 is configured to switch to a cell covered by the second alternative base station if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is received.

Referring to fig. 10, fig. 10 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 9, the apparatus further comprising:

an execution module 340, configured to discard a data unit corresponding to a currently stored packet data convergence protocol PDCP layer, and reduce a transmission sequence number of the data unit corresponding to the PDCP layer by one.

Referring to fig. 11, fig. 11 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 9, the apparatus further comprising:

a second sending module 350, configured to send a measurement report to a currently accessed source base station, where the measurement report is used by the source base station to determine whether the terminal needs to perform cell handover;

a second determining module 360, configured to, if a cell handover command message carrying a plurality of alternative base stations returned by the source base station is received, take one of the plurality of alternative base stations whose reference signal quality meets a preset cell selection condition as the first alternative base station;

a second handover module 370 is configured to request a handover from the current cell to a cell covered by the first alternative base station.

Referring to fig. 12, fig. 12 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 11, and the first determining module 310 includes:

a determining submodule 311, configured to take, as the second alternative base station, one alternative base station that does not receive the cell reconfiguration complete message sent by the terminal and that satisfies a preset cell selection condition in reference signal quality.

Referring to fig. 13, fig. 13 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 12, the apparatus further comprising:

and a control module 380, configured to control the first determining module 310 to repeat the determining of the second alternative base station if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, and then control the first transmitting module 320 to transmit a cell reconfiguration complete message to the second alternative base station until the handover to the cell covered by the second alternative base station is successful.

Referring to fig. 14, fig. 14 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 13, the apparatus further comprising:

a first starting module 410, configured to start a cell reestablishment procedure if the duration of cell handover performed by the terminal reaches the effective duration indicated by the handover timer parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received.

Referring to fig. 15, fig. 15 is a block diagram of another cell switching apparatus according to the embodiment shown in fig. 13, the apparatus further comprising:

and a second starting module 420, configured to start a cell reestablishment procedure if the number of times of cell handover performed by the terminal reaches the maximum value indicated by the handover counter parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received.

For the device embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the elements described above as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the objectives of the disclosed solution. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

Accordingly, the present disclosure also provides a computer-readable storage medium storing a computer program for executing any one of the above-described cell handover methods.

Correspondingly, the disclosure also provides a cell switching device, which is used for a terminal and comprises:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to:

Fig. 16 is a schematic diagram illustrating a structure of a cell switching apparatus according to an exemplary embodiment. As shown in fig. 16, a cell switching apparatus 1600 is shown according to an exemplary embodiment, where the apparatus 1600 may be a computer, a mobile phone, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, an exercise device, a personal digital assistant, or the like.

Referring to fig. 16, apparatus 1600 may include one or more of the following components: a processing component 1601, a memory 1602, a power component 1603, a multimedia component 1604, an audio component 1605, an input/output (I/O) interface 1606, a sensor component 1607, and a communication component 1608.

The processing component 1601 generally controls overall operation of the device 1600, such as operations associated with display, telephone call, data communication, camera operations, and recording operations. The processing component 1601 may include one or more processors 1609 to execute instructions to perform all or part of the steps of the methods described above. Further, the processing component 1601 may include one or more modules to facilitate interactions between the processing component 1601 and other components. For example, the processing component 1601 may include a multimedia module to facilitate interaction between the multimedia component 1604 and the processing component 1601.

Memory 1602 is configured to store various types of data to support operations at device 1600. Examples of such data include instructions for any application or method operating on device 1600, contact data, phonebook data, messages, pictures, video, and the like. Memory 1602 may be implemented by any type of volatile or nonvolatile memory device or combination of volatile or nonvolatile memory devices such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disk.

Power supply assembly 1603 provides power to the various components of device 1600. Power supply component 1603 can include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power for device 1600.

The multimedia component 1604 includes a screen between the device 1600 and the user that provides an output interface. In some embodiments, the screen may include a Liquid Crystal Display (LCD) and a Touch Panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from a user. The touch panel includes one or more touch sensors to sense touches, swipes, and gestures on the touch panel. The touch sensor may sense not only the boundary of a touch or slide action, but also the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 1604 includes a front-facing camera and/or a rear-facing camera. The front camera and/or the rear camera may receive external multimedia data when the device 1600 is in an operational mode, such as a capture mode or a video mode. Each front camera and rear camera may be a fixed optical lens system or have focal length and optical zoom capabilities.

The audio component 1605 is configured to output and/or input audio signals. For example, audio component 1605 includes a Microphone (MIC) configured to receive external audio signals when device 1600 is in an operational mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signals may be further stored in the memory 1602 or transmitted via the communication component 1608. In some embodiments, the audio component 1605 further comprises a speaker for outputting audio signals.

The I/O interface 1606 provides an interface between the processing component 1601 and peripheral interface modules, which may be a keyboard, click wheel, buttons, etc. These buttons may include, but are not limited to: homepage button, volume button, start button, and lock button.

The sensor assembly 1607 includes one or more sensors for providing status assessment of various aspects of the apparatus 1600. For example, the sensor assembly 1607 may detect the on/off state of the device 1600, the relative positioning of the components, such as the display and keypad of the device 1600, the sensor assembly 1607 may also detect the change in position of the device 1600 or a component of the device 1600, the presence or absence of user contact with the device 1600, the orientation or acceleration/deceleration of the device 1600, and the change in temperature of the device 1600. The sensor assembly 1607 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly 1607 may also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 1607 may also include an acceleration sensor, a gyroscopic sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

The communication component 1608 is configured to facilitate communication between the apparatus 1600 and other devices, either wired or wireless. The device 1600 may access a wireless network based on a communication standard, such as WiFi,2G, or 3G, or a combination thereof. In one exemplary embodiment, the communication component 1608 receives broadcast signals or broadcast related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, the communication component 1608 further includes a Near Field Communication (NFC) module to facilitate short range communications. For example, the NFC module may be implemented based on Radio Frequency Identification (RFID) technology, infrared data association (IrDA) technology, ultra Wideband (UWB) technology, bluetooth (BT) technology, and other technologies.

In an exemplary embodiment, the apparatus 1600 may be implemented by one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic elements for executing the methods described above.

In an exemplary embodiment, a non-transitory computer readable storage medium is also provided, such as a memory 1602, including instructions executable by the processor 1609 of the apparatus 1600 to perform the above-described method. For example, the non-transitory computer readable storage medium may be ROM, random Access Memory (RAM), CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

Wherein the instructions in the storage medium, when executed by the processor, enable apparatus 1600 to perform any one of the above-described cell handover methods for the terminal side.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any adaptations, uses, or adaptations of the disclosure following the general principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for cell handover, the method being for a terminal, the method comprising:

in response to a failure to switch from a current cell to a cell covered by a first alternative base station, not performing cell reconstruction, but sending a cell reconfiguration complete message to a second alternative base station; the first alternative base station is one of a plurality of alternative base stations, wherein the reference signal quality of the plurality of alternative base stations meets the preset cell selection condition, and the plurality of alternative base stations are determined based on the cell switching command message sent by the source base station; the second alternative base station is one of the plurality of alternative base stations, wherein the reference signal quality of the one of the plurality of alternative base stations meets a preset cell selection condition and is different from that of the first alternative base station, and the second alternative base station does not receive a cell reconfiguration complete message sent by the terminal;

And responding to receiving the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station, and switching to the cell covered by the second alternative base station.

2. The method of claim 1, wherein if the handover from the current cell request to the cell covered by the first alternative base station fails, the method further comprises:

3. The method of claim 1, wherein prior to the step of responding to a failure to handover from the current cell to the cell covered by the first alternative base station, the method further comprises:

transmitting a cell reconfiguration complete message to the first alternative base station, and starting a timer;

and determining that the switching from the current cell to the cell covered by the first alternative base station fails in response to the timer timeout.

4. The method according to claim 1, wherein the method further comprises:

and sending a measurement report to the source base station, wherein the measurement report is used for determining whether the terminal needs to perform cell switching or not by the source base station.

5. The method according to claim 1, wherein the method further comprises:

6. The method according to claim 1, wherein the cell handover command message carries handover parameters; the switching parameters include any one of a switching timer parameter and a switching counter parameter;

7. The method of claim 6, wherein the method further comprises:

8. The method of claim 6, wherein the method further comprises:

9. A cell switching apparatus for a terminal, the apparatus comprising:

a first transmitting module configured to transmit a cell reconfiguration complete message to a second alternative base station without performing cell reestablishment in response to a cell failure to switch from a current cell to a coverage of the first alternative base station; the first alternative base station is one of a plurality of alternative base stations, wherein the reference signal quality of the plurality of alternative base stations meets the preset cell selection condition, and the plurality of alternative base stations are determined based on the cell switching command message sent by the source base station; the second alternative base station is one of the plurality of alternative base stations, wherein the reference signal quality of the one of the plurality of alternative base stations meets a preset cell selection condition and is different from that of the first alternative base station, and the second alternative base station does not receive a cell reconfiguration complete message sent by the terminal;

And the first switching module is configured to respond to receiving the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station and switch to the cell covered by the second alternative base station.

10. The apparatus of claim 9, wherein the apparatus further comprises:

and the execution module is configured to discard the data unit corresponding to the PDCP layer of the current stored packet data convergence protocol and reduce the transmission sequence number of the data unit corresponding to the PDCP layer by one after the failure of requesting to switch from the current cell to the cell covered by the first alternative base station.

11. The apparatus of claim 9, wherein the apparatus further comprises:

a first starting module configured to send a cell reconfiguration complete message to a first alternative base station and start a timer before a step of responding to a failure of a handover from a current cell to a cell covered by the first alternative base station;

a first determination module configured to determine, in response to the timer expiring, that a handover from the current cell to a cell covered by a first alternative base station has failed.

12. The apparatus of claim 9, wherein the apparatus further comprises:

And the second sending module is configured to send a measurement report to the source base station, wherein the measurement report is used for determining whether the terminal needs to perform cell switching or not by the source base station.

13. The apparatus of claim 9, wherein the apparatus further comprises:

and the control module is configured to repeatedly determine the second alternative base station if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received, and then send a cell reconfiguration complete message to the second alternative base station until the cell is successfully switched to the cell covered by the second alternative base station.

14. The apparatus of claim 9, wherein the cell handover command message carries handover parameters; the switching parameters include any one of a switching timer parameter and a switching counter parameter;

15. The apparatus of claim 14, wherein the apparatus further comprises:

And the second starting module is configured to start a cell reestablishment flow if the cell switching duration of the terminal reaches the effective duration indicated by the switching timer parameter and the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal returned by the second alternative base station is not received.

16. The apparatus of claim 14, wherein the apparatus further comprises:

and the third starting module is configured to start a cell reestablishment flow if the number of times of cell switching performed by the terminal reaches the maximum value indicated by the switching counter parameter and the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal returned by the second alternative base station is not received.

17. A computer readable storage medium, characterized in that the storage medium stores a computer program for performing the cell handover method according to any of the preceding claims 1-8.

18. A cell switching apparatus, the apparatus being for a terminal, comprising:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to execute the executable instructions to implement the cell handover method of claim 1.