CN109196909B

CN109196909B - Cell switching method and device

Info

Publication number: CN109196909B
Application number: CN201880001861.8A
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: 2021-10-08
Anticipated expiration: 2038-09-03
Also published as: CN109196909A; CN113873607B; WO2020047696A1; CN113873607A

Abstract

The present disclosure provides a cell switching method and device, wherein the method includes: determining a second alternative base station if the switching from the current cell to the cell covered by the first alternative base station fails; sending a cell reconfiguration complete message to the second alternative base station; and if receiving the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the second alternative base station, switching to a cell covered by the second alternative base station. In the present disclosure, the terminal may perform cell handover again after the cell handover fails, thereby avoiding a large time delay caused by cell reconstruction and improving the terminal performance.

Description

Cell switching method and device

Technical Field

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

Background

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

And the source base station determines whether the terminal needs to carry out 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 confirm completion, 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 covered by the plurality of alternative base stations.

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

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 is failed, and at this time, the terminal initiates a cell reestablishment process. However, the cell re-establishment causes a large delay.

Disclosure of Invention

In order 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 the embodiments of the present disclosure, there is provided a cell handover method, where the method is used for a terminal, and the method includes:

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

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

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

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

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

Optionally, the method further comprises:

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

if receiving a cell switching command message which is returned by the source base station and carries a plurality of candidate base stations, taking one candidate base station of the plurality of candidate base stations, the reference signal quality of which meets a preset cell selection condition, as the first candidate base station;

requesting handover from a current cell to a cell covered by the first alternative base station.

Optionally, the determining the second alternative base station includes:

and taking one of the multiple candidate base stations which does not receive the cell reconfiguration completion message sent by the terminal and has reference signal quality meeting preset cell selection conditions as the second candidate base station.

Optionally, the method further comprises:

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 completion message to the second alternative base station until the handover is successfully carried out to the cell covered by the second alternative base station.

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

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

the handover counter parameter is used for indicating the maximum value of the accumulated cell handover times of the terminal.

Optionally, the method further comprises:

and if the time length of the cell switching of the terminal 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, which is returned by the second alternative base station, is not received, starting a cell reconstruction process.

Optionally, the method further comprises:

and if the times of cell switching accumulated 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, which is returned by the second alternative base station, is not received, starting a cell reconstruction process.

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

a first determining module configured to determine a second alternative base station if handover from the current cell 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, which is returned by the second alternative base station, is received.

Optionally, the apparatus further comprises:

the execution module is configured to discard a currently stored data unit corresponding to a Packet Data Convergence Protocol (PDCP) layer, and subtract one from a transmission sequence number of the data unit corresponding to the PDCP layer.

Optionally, the apparatus further comprises:

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

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

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

Optionally, the first determining module includes:

a determining submodule configured to use one of the candidate base stations that does not receive the cell reconfiguration complete message sent by the terminal and whose reference signal quality satisfies a preset cell selection condition as the second candidate 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 candidate base station if the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the second candidate base station, is not received, and then control the first sending module to send a cell reconfiguration completion message to the second candidate base station until the handover is successfully performed to the cell covered by the second candidate base station.

Optionally, the apparatus further comprises:

and the first starting module is configured to start a cell reestablishing process if the time length for the terminal to perform cell handover reaches the effective time length indicated by the handover timer parameter and the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the second alternative base station, is not received.

Optionally, the apparatus further comprises:

and the second starting module is configured to start the cell reestablishing process 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, which is 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 the embodiments of the present disclosure, there is provided a cell switching apparatus, where the apparatus is used for a terminal, and the apparatus includes:

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 have the following beneficial effects:

in the embodiment of the disclosure, if the terminal fails to request handover from the current cell to the cell covered by the first alternative base station, the terminal may determine a second alternative base station without cell reconstruction, and send a cell reconfiguration complete message to the second alternative base station; and if receiving the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the second alternative base station, switching to a cell covered by the second alternative base station. Through the process, the terminal can perform cell switching again after cell switching fails, so that large time delay caused by cell reconstruction is avoided, and the terminal performance is improved.

In the embodiment of the disclosure, after a failure of requesting handover from a current cell to a cell covered by a first candidate base station, a terminal may discard a data unit corresponding to a currently stored packet data convergence protocol PDCP layer, and subtract one from a transmission sequence number of the data unit corresponding to the PDCP layer. And ensuring the accuracy of the encryption and integrity protection algorithm of the terminal at the PDCP layer so that the subsequent terminal can send a sending cell reconfiguration complete message to the second alternative base station again.

In the embodiment of the present disclosure, a terminal may send a measurement report to a 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 may select one alternative base station, of the plurality of alternative base stations, of which the reference signal quality meets a preset cell selection condition as a first alternative base station, and then request to switch to a cell covered by the first alternative base station from the current cell. The usability is high.

In this embodiment of the present disclosure, when determining the second candidate base station, the terminal may select, as the second candidate base station, one candidate base station that does not receive the cell reconfiguration complete message sent by the terminal and whose reference signal quality satisfies the preset cell selection condition, from among the multiple candidate base stations provided by the source base station. In the embodiment of the disclosure, the terminal may determine the second candidate base station when performing cell handover again according to the multiple candidate base stations provided by the source base station, which is simple and convenient to implement and high in availability.

In the embodiment of the present disclosure, if the terminal does not receive the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the second candidate base station, the step of determining the second candidate base station before is repeated, and then a cell reconfiguration complete message is sent to the second candidate base station until the handover is successfully performed to the cell covered by the second candidate base station. In the above embodiment, after the terminal fails to request handover from the current cell to the cell covered by the first alternative base station, the terminal may request handover to the second alternative base station, and if the handover fails again, the terminal may re-determine a new second alternative base station, and perform cell handover again until the handover is successfully performed to the cell covered by the second alternative base station. Avoid carrying on the great time delay that the district rebuilds and cause, promoted terminal performance.

In the embodiment of the present disclosure, the source base station may carry a handover parameter when returning the handover command message, where the handover parameter may be any one of a handover timer parameter and a handover counter parameter. Optionally, the handover timer parameter is used to indicate an effective duration of cell handover performed by the terminal; the handover counter parameter is used for indicating the maximum value of the accumulated cell handover times of the terminal. The terminal can control the time length for carrying out cell switching or the times for carrying out cell switching accumulatively according to the switching parameters, so that the cell reconstruction process is started under the condition that the cell switching time length is long or the times for carrying out cell switching accumulatively are large, and the phenomenon that the terminal carries out cell switching for many times to cause large time delay is avoided. And ensuring the normal operation of the 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 diagram illustrating a cell handover scenario in the related art according to an exemplary embodiment.

Fig. 2 is a flowchart illustrating a cell handover method according to an exemplary embodiment.

Fig. 3 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 4 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 5 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 6 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 7 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 8 is a flow chart illustrating another method of cell handover in accordance with an example embodiment.

Fig. 9 is a block diagram illustrating a cell switching apparatus according to an example embodiment.

Fig. 10 is a block diagram illustrating another cell switching apparatus according to an example embodiment.

Fig. 11 is a block diagram illustrating another cell switching apparatus according to an example embodiment.

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

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

Fig. 14 is a block diagram illustrating another cell switching apparatus according to an example embodiment.

Fig. 15 is a block diagram illustrating another cell switching apparatus according to an example embodiment.

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

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended 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 and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such 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 "when … …" or "in response to a determination", depending on the context.

The disclosed embodiments provide a cell switching method, which may be used for a terminal, such as a smart phone, a tablet computer, a Personal Digital Assistant (PDA), and the like. Fig. 2 is a flowchart illustrating a method for cell handover according to an exemplary embodiment, where the method includes:

in step 101, if the request for switching from the current cell to the cell covered by the first alternative base station fails, 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, which is returned by the second candidate base station, is received, the cell covered by the second candidate base station is switched to.

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

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

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

In this step, the terminal may send a cell reconfiguration complete message to the first candidate 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 scheduling information of the PDCCH (Physical Downlink Control Channel) corresponding to the terminal, which is returned by the first candidate base station, is not received when the timer is overtime, the terminal determines that the request for switching from the current cell to the cell covered by the first candidate base station fails.

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

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 the base station A, the base station A already receives the cell reconfiguration complete message sent by the terminal, and the base stations B and C do not receive the cell reconfiguration complete message sent by the terminal. The terminal may select, from the base station B and the base station C, one candidate base station whose reference signal quality satisfies a preset cell selection condition, assume that the base station B is used as the second candidate base station, and use the second candidate base station as the second candidate base station.

If neither base station B nor base station C receives the cell reconfiguration complete message sent by the terminal and both satisfy that the reference signal quality satisfies the preset cell selection condition, then one candidate base station with better reference signal quality may be selected as the second candidate base station.

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

For step 103, if the terminal receives the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the second candidate base station, before the T304 timer expires, the terminal may perform a cell handover procedure according to the related art, and handover the terminal to the cell covered by the second candidate base station.

In the above embodiment, the terminal may perform cell handover again after the cell handover fails, thereby avoiding a large time delay caused by cell reconstruction and improving the terminal performance.

In an embodiment, referring to fig. 3, fig. 3 is a flowchart of another cell handover method according to the embodiment shown in fig. 2, where, after a handover request from a current cell to a cell covered by a first alternative base station fails, the cell handover method may further include the following steps:

in step 104, the currently stored data unit corresponding to the packet data convergence protocol PDCP layer is discarded, and the transmission sequence number of the data unit corresponding to the PDCP layer is decremented by one.

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

The input parameters corresponding to the algorithm of encryption and integrity protection comprise: direct, BEARER and COUNT. Wherein the DIRECTION is used for representing the data transmission DIRECTION; BEARER is used for indicating the radio BEARER identification of the terminal; the COUNT is a counter, and is composed of HFN (hyper frame number) and a PDCP layer transmission sequence number, where the PDCP layer adds one to the transmission sequence number every time a data unit corresponding to one PDCP is transmitted.

In the embodiment of the present disclosure, since the terminal fails to request handover to the first candidate base station before, the transmission sequence number of the data unit corresponding to the PDCP layer is incremented by one. In order to ensure that the terminal can initiate the cell reconfiguration complete message to the second alternative base station again, the currently stored data unit corresponding to the packet data convergence protocol PDCP layer can be discarded, and the transmission sequence number of the data unit corresponding to the PDCP layer can be reduced by one. Optionally, the Data Unit corresponding to the PDCP layer includes a PDU (Protocol Data Unit) and an SDU (service Data Unit).

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

In the above embodiment, after the failure of requesting handover from the current cell to the cell covered by the first candidate base station, the terminal may discard the currently stored data unit corresponding to the packet data convergence protocol PDCP layer, and subtract one from the transmission sequence number of the data unit corresponding to the PDCP layer. And ensuring the accuracy of the encryption and integrity protection algorithm of the terminal at the PDCP layer 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 illustrating another cell handover method according to the embodiment illustrated in fig. 2, where the method further includes:

in step 100-1, sending a measurement report to a currently accessed source base station, where the measurement report is used for the source base station to determine whether the terminal needs to perform cell handover;

in this step, the terminal first sends a measurement report to the currently accessed source base station according to the related technology, and the source base station may determine whether the terminal needs to perform cell handover according to the measurement report.

In step 100-2, if a cell handover command message carrying multiple candidate base stations returned by the source base station is received, taking one of the multiple candidate base stations whose reference signal quality meets a preset cell selection condition as the first candidate base station;

in this step, if cell switching is required, the source base station may determine a plurality of candidate base stations according to a related technique, and send a cell switching request to the plurality of candidate base stations, after the plurality of candidate base stations respectively return an acknowledgement message to allow the terminal to perform cell switching, the source base station returns a cell switching command message carrying the plurality of candidate base stations to the terminal, and the terminal may receive the cell switching command message according to the related technique.

Further, the terminal may select, as the first candidate base station, one candidate base station whose reference signal quality satisfies a preset cell selection condition from among the multiple candidate base stations provided by the source base station. Optionally, 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, which may be a T304 timer used in system handover. If the terminal receives the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the first alternative base station before the timer times out, the terminal may continue to execute the cell handover procedure according to the related technology, and handover the cell to the cell covered by the first alternative base station.

And if the terminal does not receive the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the first alternative base station, before the time-out of the timer, the terminal fails to request to switch to the cell covered by the first alternative base station from the current cell. At this time, the terminal may perform the above steps 101 to 103 to switch to the cell covered by the second candidate 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 may select one alternative base station, of the plurality of alternative base stations, of which the reference signal quality meets a preset cell selection condition as a first alternative base station, and then request to switch to a cell covered by the first alternative base station from the current cell. The usability is high.

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

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

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

In an embodiment, referring to fig. 5, fig. 5 is a flowchart illustrating another cell handover method according to the embodiment illustrated in fig. 4, where the cell handover 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 candidate base station is not received, the step of determining the second candidate base station is repeated, and then a cell reconfiguration complete message is sent to the second candidate base station until the handover is successful to the cell covered by the second candidate base station.

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

According to the step 101-1, one candidate base station which does not receive the cell reconfiguration complete message sent by the terminal and whose reference signal quality meets the preset cell selection condition 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 the base station A, the base station A already receives the cell reconfiguration complete message sent by the terminal, and the base stations B and C do not receive the cell reconfiguration complete message sent by the terminal. The terminal may select, from the base station B and the base station C, one candidate base station whose reference signal quality satisfies the preset cell selection condition, assuming that the candidate base station is the base station B, and then take the base station B as the second candidate 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, which is returned by the base station B, is not received before the T304 timer expires, the terminal may determine a new second candidate base station again among the multiple candidate base stations, and at this time, the base station C may be used as the new second candidate base station.

After determining a new second candidate base station, the terminal sends a cell reconfiguration complete message to the new second candidate base station, and if the scheduling information of the physical downlink control channel PDCCH corresponding to the terminal, which is returned by the second candidate base station, is received before the timer of T304 times out, the terminal may switch to a cell covered by the second candidate 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, which is returned by the new second candidate base station, the step 101-1 may be repeated again, and then a cell reconfiguration complete message may be sent to the second candidate base station until the terminal is successfully switched to the cell covered by the second candidate 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, which is returned by the second candidate base station, the step of determining the second candidate base station is repeated, and then a cell reconfiguration complete message is sent to the second candidate base station until the handover is successful to the cell covered by the second candidate base station. In the above embodiment, after the terminal fails to request handover from the current cell to the cell covered by the first alternative base station, the terminal may request handover to the second alternative base station, and if the handover fails again, the terminal may re-determine a new second alternative base station, and perform cell handover again until the handover is successfully performed to the cell covered by the second alternative base station. Avoid carrying on the great time delay that the district rebuilds and cause, promoted terminal performance.

In an embodiment, if the terminal performs cell handover for a long time or multiple times, a large time delay is also caused, and the terminal service is affected. 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 handover parameter comprises any one of a handover timer parameter and a handover counter parameter; the switching timer parameter is used for indicating the effective duration of cell switching of the terminal; the handover counter parameter is used for indicating the maximum value of the accumulated cell handover times of the terminal.

The terminal can control the time length of cell switching or the number of times of cell switching according to the switching parameters.

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

in step 106, if the duration of the cell handover performed by the terminal reaches the effective duration indicated by the handover timer parameter and the scheduling information of the PDCCH corresponding to the terminal and returned by the second candidate base station is not received, a cell re-establishment procedure is started.

In this step, the terminal may start a handover timer when it fails to request handover from the current cell to the cell covered by the first candidate base station, where a duration of the handover timer is an effective duration indicated by a parameter of the handover timer. And the terminal sends a cell reconfiguration completion message to the second alternative base station, and if the switching timer is overtime and the terminal still does not receive the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the second alternative base station, the terminal can stop cell switching and start a cell reconstruction process according to the related technology.

Optionally, the terminal may start the handover timer when requesting handover from the current cell to the cell covered by the first alternative base station, if the terminal fails to request 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 still does not receive scheduling information of a physical downlink control channel PDCCH corresponding to the terminal and returned by the second alternative base station, the terminal may stop performing cell handover, and start a cell reconstruction process according to the related technology.

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

in step 107, 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 PDCCH corresponding to the terminal and returned by the second candidate base station is not received, a cell re-establishment procedure is started.

In this step, the terminal may start a handover counter after the terminal fails to request handover from the current cell to the cell covered by the first candidate base station, where an initial value of the handover counter is zero. And the terminal adds 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 of cell switching by 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, which is returned by the second alternative base station, the terminal can stop cell switching, and start a cell reconstruction process according to the related technology.

Alternatively, the terminal may start the handover counter when requesting handover from the current cell to the cell covered by the first alternative base station, and the initial value of the handover counter is zero. And if the terminal fails to request to switch to the cell covered by the first alternative base station from the current cell, the value of the switching counter is increased by one. And the terminal adds one to the value of the switching counter every time the terminal sends a cell reconfiguration completion message to the second alternative base station. And when the number of times of cell handover performed by the terminal reaches the maximum value indicated by the handover counter parameter, that is, the number of times counted by the handover 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 candidate base station, the terminal may stop performing cell handover, and start a cell reconstruction process according to the related technology.

In the above embodiment, the source base station may carry the handover parameter when returning the handover command message, where the handover parameter may be any one of a handover timer parameter and a handover counter parameter. Optionally, the handover timer parameter is used to indicate an effective duration of cell handover performed by the terminal; the handover counter parameter is used for indicating the maximum value of the accumulated cell handover times of the terminal. The terminal can control the time length for carrying out cell switching or the times for carrying out cell switching accumulatively according to the switching parameters, so that the cell reconstruction process is started under the condition that the cell switching time length is long or the times for carrying out cell switching accumulatively are large, and the phenomenon that the terminal carries out cell switching for many times to cause large time delay is avoided. And ensuring the normal operation of the terminal service.

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

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

wherein the measurement report is used for 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 candidate base stations and handover parameters returned by the source base station is sent to the terminal.

In this step, the source base station determines that the terminal needs to perform cell handover, and then sends a handover request to the multiple second candidate base stations, and after the multiple second candidate base stations confirm that the handover request is completed, the source base station sends a cell handover command message to the terminal (not shown in fig. 8), where the cell handover command message carries configuration information of target cells covered by the multiple second candidate base stations.

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

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

In this step, the terminal takes, as the second candidate base station, one of the candidate base stations that has not received the cell reconfiguration complete message sent by the terminal and whose reference signal quality satisfies a preset cell selection condition.

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 PDCCH corresponding to the terminal, which is returned by the second candidate 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, which is returned by the second candidate base station, the terminal is switched to the cell covered by the second candidate base station.

In step 209, if the duration of cell handover performed by the terminal reaches the effective duration indicated by the handover timer parameter or the number of times of cell handover performed by the terminal cumulatively reaches the maximum value indicated by the handover counter parameter, and the scheduling information of the PDCCH corresponding to the terminal and returned by the second candidate base station is not received, a cell re-establishment procedure is started.

The above examples are further illustrated as follows.

Example 1, when the terminal receives a cell handover command message sent by a source base station, the cell handover command message carries a plurality of candidate 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 complete message to the base station A to perform cell switching failure, the terminal discards a data unit corresponding to a currently stored PDCP layer, including a PDU and an SDU, subtracts one from a sending sequence number of the data unit corresponding to the PDCP layer, and starts a switching timer, wherein the time length of the switching timer is T.

And 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 to switch the cell again, the terminal discards the currently stored data unit corresponding to the PDCP layer again at this moment, including the PDU and the SDU, and subtracts one from the transmission sequence number of the data unit corresponding to the PDCP layer.

And 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. And if the switching timer is overtime, the terminal starts a cell reconstruction process.

Example 2, when the terminal receives a cell handover command message sent by a source base station, the cell handover command message carries a plurality of candidate 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 a data unit corresponding to a currently stored PDCP layer, including a PDU and an SDU, and subtracts one from a sending sequence number of the data unit corresponding to the PDCP layer, and adds one to the number of times of cell switching accumulated by the terminal every time cell switching is initiated from zero.

And 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 to switch the cell again, the terminal discards the currently stored data unit corresponding to the PDCP layer again at this moment, including the PDU and the SDU, and subtracts one from the transmission sequence number of the data unit corresponding to the PDCP layer. And the accumulated times of cell switching of the terminal is added to one.

And if the switching is successful, stopping accumulating the times of the accumulated cell switching by the terminal. And if the times of cell switching accumulated by the terminal reach the maximum times, the terminal starts a cell reconstruction process.

In the above embodiment, the terminal may perform cell handover again after the cell handover fails, thereby avoiding a large time delay caused by cell reconstruction and improving the terminal performance. In addition, the terminal can control the time length for carrying out cell switching or the times for carrying out cell switching accumulatively according to the switching parameters, thereby carrying out cell reconstruction under the condition of longer cell switching time or more accumulated switching times and avoiding larger time delay caused by cell switching carried out for many times by the terminal. And ensuring the normal operation of the terminal service.

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

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

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

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

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

the execution module 340 is configured to discard a currently stored data unit corresponding to the 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 shown on the basis of the embodiment shown in fig. 9, the apparatus further includes:

a second sending module 350, configured to send a measurement report to a currently accessed source base station, where the measurement report is used for 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 multiple candidate base stations returned by the source base station is received, take one of the multiple candidate base stations whose reference signal quality meets a preset cell selection condition as the first candidate base station;

a second handover module 370 configured to request 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 shown on the basis of the embodiment shown in fig. 11, where the first determining module 310 includes:

the determining submodule 311 is configured to use, as the second candidate base station, one of the candidate base stations that does not receive the cell reconfiguration complete message sent by the terminal and has reference signal quality meeting a preset cell selection condition.

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

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

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

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, which is returned by the second candidate base station, is not received.

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

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 scheduling information of the physical downlink control channel PDCCH corresponding to the terminal and returned by the second candidate base station is not received.

For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the disclosed solution. One of ordinary skill in the art can understand and implement it without inventive effort.

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

Correspondingly, the present disclosure further provides a cell switching apparatus, where the apparatus is used for a terminal, and the apparatus includes:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to:

Fig. 16 is a schematic structural diagram illustrating 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: processing component 1601, memory 1602, power component 1603, multimedia component 1604, audio component 1605, input/output (I/O) interface 1606, sensor component 1607, and communication component 1608.

The processing component 1601 generally controls the overall operation of the device 1600, such as operations associated with display, telephone calls, data communications, camera operations, and recording operations. 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, processing component 1601 may include one or more modules that facilitate interaction between processing component 1601 and other components. For example, processing component 1601 can include a multimedia module to facilitate interaction between multimedia component 1604 and processing component 1601.

The memory 1602 is configured to store various types of data to support operation at the apparatus 1600. Examples of such data include instructions for any application or method operating on device 1600, contact data, phonebook data, messages, pictures, videos, and so forth. The memory 1602 may be implemented by any type or combination of volatile or non-volatile 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 disks.

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

The multimedia component 1604 includes a screen that provides an output interface between the device 1600 and a user. 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 an input signal from a user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundary of a touch or slide action, but also detect 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 operating mode, such as a shooting mode or a video mode. Each front camera and rear camera may be a fixed optical lens system or have a focal length and optical zoom capability.

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 apparatus 1600 is in an operational mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signals may further be stored in memory 1602 or transmitted via communication component 1608. In some embodiments, audio component 1605 also includes a speaker for outputting audio signals.

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

The sensor assembly 1607 includes one or more sensors for providing various aspects of status assessment for the device 1600. For example, sensor assembly 1607 may detect an open/closed state of device 1600, the relative positioning of components, such as a display and keypad of device 1600, the change in position of device 1600 or a component of device 1600, the presence or absence of user contact with device 1600, the orientation or acceleration/deceleration of device 1600, and the change in temperature of 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 gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

The communication component 1608 is configured to facilitate wired or wireless communication between the apparatus 1600 and other devices. The device 1600 may access a wireless network based on a communication standard, such as WiFi, 2G, or 3G, or a combination thereof. In an exemplary embodiment, the communication component 1608 receives the broadcast signal or broadcast associated information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 1608 further includes a Near Field Communication (NFC) module to facilitate short range communication. 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, micro-controllers, microprocessors or other electronic components for performing the above-described methods.

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

Wherein the instructions in the storage medium, when executed by the processor, enable the apparatus 1600 to perform any of the above-described cell handover methods for a 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 variations, uses, or adaptations of the disclosure following, in general, the 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 will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A cell switching method, wherein the method is used for a terminal, and the method comprises:

if receiving scheduling information of a Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the second alternative base station, switching to a cell covered by the second alternative base station;

the first candidate base station is a candidate base station which is provided for the terminal and has reference signal quality meeting preset cell selection conditions among a plurality of candidate base stations when the source base station determines that the terminal needs to perform cell switching according to a measurement report sent by the terminal;

the second candidate base station is one of the candidate base stations which does not receive the cell reconfiguration completion message sent by the terminal and has reference signal quality meeting the preset cell selection condition.

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

3. The method of claim 1, further comprising:

4. The method of claim 1, further comprising:

5. The method of claim 3, wherein the cell switching command message carries a switching parameter; the handover parameter comprises any one of a handover timer parameter and a handover counter parameter;

6. The method of claim 5, further comprising:

7. The method of claim 5, further comprising:

8. A cell switching apparatus, wherein the apparatus is used for a terminal, the apparatus comprising:

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

9. The apparatus of claim 8, further comprising:

and the execution module is configured to discard the currently stored data unit corresponding to the packet data convergence protocol PDCP layer and reduce the sending sequence number of the data unit corresponding to the PDCP layer by one if the request for switching from the current cell to the cell covered by the first alternative base station fails.

10. The apparatus of claim 8, further comprising:

11. The apparatus of claim 8, further comprising:

and the control module is configured to control the first determining module to repeatedly determine the second alternative base station if the scheduling information of the Physical Downlink Control Channel (PDCCH) corresponding to the terminal, which is returned by the second alternative base station, is not received, and then control the first sending module to send a cell reconfiguration completion message to the second alternative base station until the handover is successfully performed to the cell covered by the second alternative base station.

12. The apparatus of claim 10, wherein the cell switch command message carries a switch parameter; the handover parameter comprises any one of a handover timer parameter and a handover counter parameter;

13. The apparatus of claim 12, further comprising:

14. The apparatus of claim 12, further comprising:

15. A computer-readable storage medium, characterized in that the storage medium stores a computer program for executing the cell handover method according to any one of the preceding claims 1 to 7.

16. A cell switching apparatus, wherein the apparatus is used for a terminal, and comprises:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to: