CN107426810B

CN107426810B - Method and device for acquiring uplink timing

Info

Publication number: CN107426810B
Application number: CN201610345246.1A
Authority: CN
Inventors: 徐汉青; 赵亚军; 吴昱民
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2016-05-23
Filing date: 2016-05-23
Publication date: 2022-04-29
Anticipated expiration: 2036-05-23
Also published as: CN107426810A; WO2017202267A1

Abstract

The invention provides a method and a device for acquiring uplink timing, wherein the method comprises the following steps: before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell; the UE determines the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel. By adopting the technical scheme, the problem of how to accurately determine the uplink timing of the target cell is solved, and the uplink timing of the target cell is accurately acquired under the condition of reducing the random access and the whole switching time delay.

Description

Method and device for acquiring uplink timing

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for acquiring uplink timing.

Background

Maintaining a seamless, high quality connection is an important goal of cellular systems when the user or terminal is moving. For example, for a Heterogeneous Network (HetNet) composed of high-power macro cells and low-power small cells, it is particularly challenging to maintain Long Term Evolution (LTE) mobility robustness with a low Handover failure (HOF) probability in the HetNet Network. In fact, these challenges or problems have led to the introduction of mobile enhanced features in LTE Rel-12(Release 12) to address. For example, a mechanism for reducing the probability of connecting a high-speed User Equipment (UE) to a small cell is provided, fast reply is performed from Radio Link Failure (RLF), context is acquired after RLF, and the UE notifies the mobile history from the network.

Considering characteristics of Rel-12 Mobility enhancement and Self-organizing Network (SON) based Mobility Robustness Optimization (MRO), better Mobility performance with low RLF and HOF probability can be achieved. However, each LTE handover results in an interruption of the UE data transmission. Statistics have shown that the time for each handover to cause an interruption is typically 50ms, and sometimes even 80-100 ms. The break time is the result of the "break before action (break before make)" methodology that depends on each handover in LTE. Upon receiving the handover command, the UE stops ongoing data interaction with the source cell and then starts acquiring a data connection with the target cell. The latter step in the handover procedure requires the UE to perform Random Access (RA) with the target cell to obtain Timing Advance (TA) of the new cell.

The data interruption time can be reduced if the UE does not need to perform a RA procedure with the target cell, which we call this mobility enhancement a RACH-less handover. The RACH-less handover scheme can reduce the interruption time in handover, avoid the need to perform random access, RA, for each handover, reduce handover delay, and improve mobility robustness. In addition, reducing the data stream interruption time is also beneficial to avoid retransmission timeout such as Transmission Control Protocol (TCP) and improving the quality of Voice Over Internet Protocol (VOIP).

For the RACH-less described above and similar techniques in wireless communications, the UE does not need to perform a complete random access procedure with the target cell. However, the UE still needs to obtain a timing advance relationship with the target cell to perform corresponding uplink timing adjustment, so as to perform uplink data interaction with the target cell. The invention provides a solution for obtaining the uplink timing advance of the target cell and how to accurately perform corresponding uplink timing adjustment.

For the problem of how to accurately determine the uplink timing of the target cell in the related art, no effective solution exists at present.

Disclosure of Invention

The embodiment of the invention provides a method and a device for acquiring uplink timing, which are used for at least solving the problem of how to accurately determine the uplink timing of a target cell in the related art.

According to an embodiment of the present invention, a method for acquiring uplink timing is provided, including: small by source at user equipment UEBefore a cell is switched to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell; the UE determines uplink timing of the target cell according to a received Timing Advance (TA) command, downlink timing of a second cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell. Optionally, the uplink signal or the uplink channel includes one of: a channel Sounding Reference Signal (SRS), a Physical Random Access Channel (PRACH), or other uplink signals or channels. Optionally, when the uplink signal or the uplink channel is an SRS or a non-PRACH, the method further includes: the UE advances value N according to the timing of the source cell_TATo determine a transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

Optionally, in a case that the first cell type and the second cell type are both source cells, the method includes: before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of the source cell; and the UE determines the uplink timing of the target cell according to the received Timing Advance (TA) command, the downlink timing of the source cell and/or the current timing advance value of the source cell, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a source cell and the second cell type is a target cell, the method includes: before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of the source cell; and the UE determines the uplink timing of the target cell according to the received Timing Advance (TA) command, the downlink timing of the target cell and/or the current timing advance value of the source cell, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a target cell and the second cell type is a target cell, the method includes: before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of the target cell; and the UE determines the uplink timing of the target cell according to the received Timing Advance (TA) command, the downlink timing of the target cell and/or the current timing advance value of the source cell, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, the performing, by the UE, timing adjustment according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell includes: the TA command is calculated by the target cell according to the uplink signal or the uplink channel, wherein the target cell notifies the TA command to the source cell by confirming a Handover Request acknowledgement or setting a Response Setup Response by X2 through a Handover Request.

Optionally, the configuration information of the uplink signal or the uplink channel is configured in the following three ways: the source cell is configured, wherein the source cell informs a target cell of the configuration through a Handover Request Handover Request or a Setup Request of X2; configuring a target cell; and the source cell and the target cell negotiate configuration.

Optionally, the first cell type and the second cell type each include: a source cell or a target cell; the UE determines the first cell type and the second cell type in one of the following ways: and sending the notification message to the source cell according to the notification message or a preset rule. Optionally, the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

Optionally, in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, and/or the timing advance value of the UE and the source cell is kept unchanged, or the uplink timing relation of the UE and the source cell is kept unchanged.

According to an embodiment of the present invention, a method for acquiring uplink timing is provided, including: before User Equipment (UE) is switched from a source cell to a target cell, the source cell sends an uplink signal or configuration information of an uplink channel to the UE; the source cell receives the uplink signal or the uplink channel sent by the UE, wherein the uplink signal or the uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell; the source cell sends a Timing Advance (TA) command to the UE, wherein the UE executes timing adjustment according to the received TA command, the downlink timing of a second cell and/or the current timing advance value of the source cell, and determines the uplink timing of the target cell through the timing adjustment, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type includes the source cell or the target cell. Optionally, before the source cell sends the configuration information of the uplink signal or the uplink channel to the UE, the method includes: and the source cell informs the configuration information to the target cell through a Handover Request Handover Request or a Setup Request of X2. Optionally, after the source cell receives the uplink signal or the uplink channel sent by the UE, the source cell notifies the target cell of the time information of receiving the uplink signal or the uplink channel, and/or the timing offset information between the source cell and the target cell. Optionally, the source cell sends a notification message to the UE through a high-level signaling, an MAC PDU/CE, a physical layer control signaling, or a physical layer control downlink channel, where the notification message is used to set the first cell type and the second cell type. Optionally, the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel. Optionally, in the UE handover procedure, the source cell does not perform uplink timing related operation for the UE, where the operation includes: the source cell does not perform timing advance measurement of the UE, or the source cell does not send a TA command of the source cell to the UE, or the uplink timing relationship between the source cell and the UE remains unchanged.

According to an embodiment of the present invention, a method for acquiring uplink timing is provided, including: before User Equipment (UE) is switched from a source cell to a target cell, the target cell receives an uplink signal or configuration information of an uplink channel sent by the source cell; the target cell calculates a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell; and the target cell sends a Timing Advance (TA) command to the UE, wherein the UE executes timing adjustment according to the received TA command, the downlink timing of a second cell and/or the current timing advance value of the source cell, and determines the uplink timing of the target cell through the timing adjustment, wherein the type of the second cell comprises the source cell or the target cell. Optionally, the sending, by the target cell, the timing advance TA command to the UE includes: and the target cell confirms a Handover Request acknowledgement or an X2set Response Setup Response through a Handover Request to inform the TA command to the source cell, wherein the source cell forwards the TA command to the UE.

According to an embodiment of the present invention, a method for acquiring uplink timing is provided, including: before User Equipment (UE) is switched from a source cell to a target cell, the UE calculates a Timing Advance (TA) of the target cell according to a timing advance value of the source cell, a transmission delay difference of downlink signals sent by the source cell and the target cell simultaneously to the UE, and/or a timing deviation of the source cell and the target cell; and the UE determines the uplink timing of the target cell through the TA.

Optionally, the method further comprises: in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, or the timing advance value of the UE and the source cell is kept unchanged, or the uplink timing relation of the UE and the source cell is kept unchanged.

According to another embodiment of the present invention, an apparatus for acquiring uplink timing is provided, which is applied to a UE, and includes: a first sending module, configured to obtain configuration information of an uplink signal or an uplink channel before a user equipment UE is switched from a source cell to a target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell; a first determining module, configured to determine uplink timing of the target cell according to a received Timing Advance (TA) command, downlink timing of a second cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell.

Optionally, the uplink signal or the uplink channel includes one of: a channel Sounding Reference Signal (SRS), a Physical Random Access Channel (PRACH), or other uplink signals or channels.

Optionally, when the uplink signal or the uplink channel is the SRS or the non-PRACH, the first sending module is further configured to forward the value N according to the timing of the source cell_TATo determine a transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

Optionally, when the first cell type and the second cell type are both source cells, the first sending module is further configured to obtain configuration information of an uplink signal or an uplink channel before the UE is switched from the source cell to the target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the source cell; the first determining module is further configured to determine, by the UE, uplink timing of the target cell according to the received timing advance TA command, downlink timing of the source cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a source cell and the second cell type is a target cell, the first sending module is further configured to obtain configuration information of an uplink signal or an uplink channel before the UE is switched from the source cell to the target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the source cell; the first determining module is further configured to determine uplink timing of the target cell according to a received timing advance TA command, downlink timing of the target cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a target cell and the second cell type is a target cell, the first sending module is further configured to obtain configuration information of an uplink signal or an uplink channel before the UE is switched from the source cell to the target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the target cell; the first determining module is further configured to determine uplink timing of the target cell according to a received timing advance TA command, downlink timing of the target cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, the first cell type and the second cell type each include: a source cell or a target cell; the UE determines the first cell type and the second cell type in one of the following ways: and sending the notification message to the source cell according to the notification message or a preset rule.

Optionally, the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

Optionally, in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, and/or the timing advance value of the UE and the source cell is kept unchanged.

According to an embodiment of the present invention, an apparatus for acquiring uplink timing is provided, which is applied to a source cell, and includes: a second sending module, configured to send an uplink signal or configuration information of an uplink channel to the UE before the UE is switched from the source cell to the target cell; a first receiving module, configured to receive the uplink signal or the uplink channel sent by the UE, where the uplink signal or the uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell; a third sending module, configured to send a Timing Advance (TA) command to the UE, where the UE performs timing adjustment according to the received TA command, downlink timing of the second cell, and/or a current timing advance value of the source cell, and determines uplink timing of the target cell through the timing adjustment, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type includes the source cell or the target cell.

Optionally, before the source cell sends the configuration information of the uplink signal or the uplink channel to the UE, the source cell notifies the configuration information to the target cell through a Handover Request or a Setup Request set 2.

Optionally, the first receiving module is further configured to, after the source cell receives the uplink signal or the uplink channel sent by the UE, notify the target cell of the received time information of sending the uplink signal or the uplink channel, and/or the timing offset information between the source cell and the target cell.

Optionally, the source cell sends a notification message to the UE through a high-level signaling, an MAC PDU/CE, a physical layer control signaling, or a physical layer control downlink channel, where the notification message is used to set the first cell type and the second cell type.

Optionally, in the UE handover procedure, the source cell does not perform uplink timing related operation for the UE, where the operation includes: the source cell does not perform timing advance measurement of the UE, or the source cell does not send a TA command of the source cell to the UE.

According to an embodiment of the present invention, an apparatus for acquiring uplink timing is provided, which is applied to a target cell, and includes: a second receiving module, configured to receive an uplink signal or configuration information of an uplink channel sent by a source cell before a user equipment UE is switched from the source cell to a target cell; a processing module, configured to calculate a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell; a fourth sending module, configured to send a Timing Advance (TA) command to the UE, where the UE performs timing adjustment according to the received TA command, downlink timing of the second cell, and/or a current timing advance value of the source cell, and determines uplink timing of the target cell through the timing adjustment, where the second cell type includes the source cell or the target cell. Optionally, the fourth sending module is further configured to notify the TA command to the source cell by a Handover Request acknowledgement message or a Setup Response message Setup through X2, where the source cell forwards the TA command to the UE.

According to an alternative embodiment of the present invention, an apparatus for acquiring uplink timing of a UE is provided, including: a calculation module, configured to calculate, according to a timing advance value of a source cell, a transmission delay difference between downlink signals simultaneously sent by the source cell and a target cell and reaching the UE, and/or a timing offset between the source cell and the target cell to obtain a timing advance TA of the target cell before a user equipment UE is switched from the source cell to the target cell; a second determining module, configured to determine uplink timing of the target cell through the TA. Optionally, the apparatus further comprises: in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, or the timing advance value of the UE and the source cell is kept unchanged, or the uplink timing relation of the UE and the source cell is kept unchanged.

According to the invention, before or during the switching of the cell by the UE, the UE sends the uplink signal or the uplink channel based on the uplink timing or the downlink timing of the source cell or the downlink timing of the target cell, the target cell can calculate the timing advance TA command according to the obtained uplink signal or the uplink channel, and the UE determines the uplink timing of the target cell according to the received TA command and the downlink timing of the source cell or the target cell, so that the problem of accurately determining the uplink timing of the target cell is solved, and the uplink timing of the target cell is accurately obtained under the condition of reducing the random access and the whole switching time delay.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a flowchart of a method for acquiring uplink timing applied to a UE side according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating a UE calculating a TA value according to an alternative embodiment of the present invention;

fig. 3 is a diagram illustrating transmission delay differences between a source cell and a target cell in an asynchronous scenario in accordance with an alternative embodiment of the present invention;

fig. 4 is a flowchart of a method for acquiring uplink timing applied to a source cell side according to an embodiment of the present invention;

fig. 5 is a flowchart of a method for acquiring uplink timing applied to a target cell side according to an embodiment of the present invention;

fig. 6 is a flowchart of a method for acquiring uplink timing according to an embodiment of the present invention;

fig. 7 is a block diagram of an apparatus for acquiring uplink timing applied to a UE according to an embodiment of the present invention;

fig. 8 is a block diagram of an apparatus for acquiring uplink timing applied to a source cell according to an embodiment of the present invention;

fig. 9 is a block diagram of an apparatus for acquiring uplink timing applied to a target cell according to an embodiment of the present invention;

fig. 10 is a block diagram of an apparatus for acquiring uplink timing according to an embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

It should be noted that the handover method described in the present application is handover of a UE between different cells, and is also applicable to handover of a UE between different base stations.

Example 1

Embodiments of the present application may operate in a cellular system (including but not limited to a cellular system), and a network architecture of a network of the system may include a network side device (e.g., a base station) and a terminal. In this embodiment, a handover method capable of operating on the network architecture is provided, and it should be noted that an operating environment of the handover method provided in this embodiment is not limited to the network architecture.

For RACH-less as described in the background and similar techniques in wireless communications, the UE does not need to perform a complete random access procedure with the target cell. However, the UE still needs to obtain the timing advance relationship with the target cell to perform corresponding uplink timing adjustment, so that the UE can quickly perform uplink data interaction with the target cell after the handover is completed. For the uplink timing advance of the target cell and how to accurately perform corresponding uplink timing adjustment, the technical scheme provided by the embodiment of the application is as follows:

a source cell configures UE to send an uplink signal or an uplink channel and informs the UE and a target cell of the configuration; or the configuration of the uplink signal or the uplink channel is determined by the target cell and is notified to the source cell, and the source cell notifies the UE; or, the configuration of the uplink signal or the uplink channel is determined by the two cells in a coordinated manner, and is notified to the UE by the source cell. The alternative uplink signal or uplink channel may be PRACH and/or SRS, or other uplink signal or uplink channel. The uplink signal or the uplink channel is mainly used for determining the timing advance or uplink timing of the UE and the target cell.

Alternatively, the alternative signal may be a non-contention PRACH. Because a longer execution time is needed for contending for RACH, for example, if a UE successfully receives its Random Access Response (RAR) in subframe n, the UE will send a message Msg3 in the first available uplink subframe of n + k1(k1 ≧ 6), and in addition, the base station is also needed to send a contention decision message. These two steps take longer.

The UE may send the uplink signal or the uplink channel based on the downlink timing of the target cell (or the downlink subframe timing and/or the downlink frame timing, which is omitted in the same manner as described in this application) based on the downlink timing of the source cell. If the uplink signal or the uplink channel is the SRS or other uplink signal or uplink channel other than the PRACH, the timing advance value N based on the current source cell is further required when the uplink signal or the uplink channel is transmitted_TAThe value (see Rel-1336.213, same below) to determine the transmission moment.

When the UE receives a timing advance command (TA command) sent by the target cell, the uplink timing of the target cell may be determined based on the downlink timing of the source cell or based on the downlink timing of the target cell. Similarly, if the uplink signal or uplink channel is SRS or other non-PRACHWhen determining the uplink timing of the target cell, the uplink signal or the uplink channel also needs to be based on the timing advance value N of the current source cell_TAThe value (see Rel-1336.213) to determine the target cell uplink timing.

After the UE determines the uplink timing interacted with the target cell, the UE can perform normal uplink and downlink data interaction with the target cell after the switching is completed.

The present application provides three solutions to the above-described methods and to the problems described in the background, the three solutions being as follows:

solution one (corresponding to alternative embodiments one and two below):

constraining before or during handover, the UE transmits an alternative uplink signal or uplink channel based on the downlink timing of the source cell or the uplink timing of the source cell. The uplink signal or uplink channel transmission configuration is known by the source cell and the target cell, and is mainly used for determining the timing advance or uplink timing of the UE and the target cell.

And/or, restricting the UE to perform timing adjustment based on the downlink timing of the source cell, and/or the received timing advance command calculated by the target cell, and/or the current timing advance value of the source cell, and determining the uplink timing of the target cell according to the timing adjustment.

Solution two (corresponding to alternative embodiments three to six below):

And/or the source cell informs the target cell of the time information of the received uplink signal or the uplink channel and/or the timing deviation information of the source cell and the target cell.

And constraining the UE to perform timing adjustment based on the downlink timing of the target cell, and/or the received timing advance command calculated by the target cell, and/or the current timing advance value of the source cell, so as to determine the uplink timing of the target cell.

Solution three (corresponding to alternative embodiments seven and eight below):

constraining before or during handover, the UE transmits an alternative uplink signal or uplink channel based on the downlink timing of the target cell. The uplink signal or uplink channel transmission configuration is known by the source cell and the target cell, and is mainly used for determining the timing advance or uplink timing of the UE and the target cell.

And/or, restricting the UE to perform timing adjustment based on the downlink timing of the target cell, and/or the received timing advance command calculated by the target cell, and/or the current timing advance value of the source cell, so as to determine the uplink timing of the target cell.

For the three solutions, for the constrained behavior of the UE, the source cell may notify the UE through a high-level signaling, a Media Access Control Protocol Data Unit (MAC PDU for short), a Media Access Control Element (MAC CE for short), a physical layer Control signaling or a physical layer Control downlink channel, and send the uplink signal or the uplink channel according to which timing, and/or determine the uplink timing of the target cell according to which timing. Optionally, the constraint behavior may be notified to the UE by the source cell in a handover command, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

Alternatively, the settings may be predefined for the constrained behavior of the UE. For example, the constraint behavior is specified by a 3GPP standard protocol, and the UE determines according to which timing to transmit the uplink signal or uplink channel and/or according to which timing to determine the uplink timing of the target cell according to the specification predefined by the standard protocol. In this case, the source cell, the target cell and the UE are all aware of this constrained behavior or timing relationship, and therefore need not be notified to the UE by the source cell.

In the above-described solution, there is a technical problem that, first, during handover, the UE gradually changes from data interaction with the source cell to data interaction with the target cell. The data interaction requirements or necessity of the source cell and the UE are reduced. If the subframe n sends a timing adjustment command in the handover process, the UE needs to start to apply the timing advance value for adjustment in subframe n + 6. Therefore, the UE is likely to have not yet adjusted the uplink timing with the source cell and has already been handed off. In RACH-less or similar techniques, the uplink timing advance calculation of the target cell is started from before handover or early in the handover process, when the source cell is still the serving cell for the UE. At this time, the source cell and the target cell both send timing advance commands, which may cause confusion of uplink sending timing of the UE; meanwhile, according to the method for calculating TA based on UE, the timing advance adjustment of the source cell may result in the timing advance adjustment of the target cell, and the UE needs to repeatedly calculate and adjust the timing advance parameter of the target cell. The UE power consumption and implementation complexity may increase.

In order to solve the above-mentioned problems, the present application describes the following solutions in addition to the above-mentioned three solutions: the method includes that a source cell does not execute uplink timing related operation aiming at the UE in a UE switching process, and/or the UE does not execute uplink timing adjustment aiming at the source cell in the UE switching process. The method specifically comprises the following steps: it is constrained that the source cell does not perform timing advance measurements for the UE during the UE handover. Or, the source cell does not send the timing advance command of the source cell to the UE during the UE handover. Or, the uplink timing relationship between the source cell and the UE is constrained to remain unchanged. Or, the UE is restricted not to execute the timing advance command sent by the source cell in the UE switching process. Or, constraining that the timing advance value of the UE and the source cell is kept unchanged during the UE handover process. Or, the uplink timing relationship between the UE and the source cell is constrained to remain unchanged. In the solution described in this document, the TA command in the second and third solutions is calculated by the target cell, and in the related art, there are two methods for calculating the TA command, one is to calculate the TA based on the base station, and the other is to calculate the TA based on the UE.

In this embodiment, a method for acquiring uplink timing running in the above network architecture is provided, and fig. 1 is a flowchart of a method for acquiring uplink timing applied to a UE side according to an embodiment of the present invention, as shown in fig. 1, the flowchart includes the following steps:

step S102, before user equipment UE is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell. Optionally, the configuration of the uplink signal or the uplink channel is known to both the source cell and the target cell.

Step S104, the UE determines the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell.

Optionally, the executing subject of the above steps may be a user equipment, etc., but is not limited thereto.

In a RACH-less scenario or similar, the following are two schemes for calculating TA (Timing Advanced), the first scheme is based on the UE calculating TA, and the other scheme is based on the eNB calculating TA.

The first method comprises the following steps: based on the UE calculating TA, fig. 2 is a schematic diagram of the UE calculating TA value according to an alternative embodiment of the present invention, and as shown in fig. 2, it is assumed that the transmission delays of the UE to the source cell (or source base station, the same below) and the target cell (or target base station, the same below) are T1 and T2, respectively. Assuming that the uplink transmission delay is the same as the downlink transmission delay, and assuming that the UL transmission delay is the same as the DL transmission delay, the UE may obtain the TA of the target cell from the TA of the source cell by the following formula:

TA_target＝TA_source-2*ΔT

wherein, T is T1-T2.

The above applies to both synchronous and asynchronous networks.

Fig. 3 is a diagram illustrating transmission delay differences between a source cell and a target cell in an asynchronous scenario according to an alternative embodiment of the present invention, which is illustrated in fig. 3, and not only the asynchronous scenario is depicted, but also a synchronous scenario, i.e., t3 is t1 and Td is 0 in fig. 3. There is no internal timing offset of the transmission between the two cells. For a synchronous network, a UE may obtain the DL transmission delay difference from the UE to the source cell and the target cell according to the DL signal receiving timing sent by the source cell and the target cell simultaneously. The UE can directly apply the calculated TA value, i.e. it executes the TA command itself.

For asynchronous networks, Δ T also needs to take into account the internal timing offset between the two cells, assuming that the internal timing offset between the target cell and the source cell is Td, as shown in fig. 3. The source cell sends a downlink signal at time T1, the UE receives a corresponding signal at time T2, and the transmission delay from the base station of the source cell to the UE is T1-T2-T1. Similarly, the target cell transmits a downlink signal at time T3, the UE receives the corresponding signal at time T4, and the transmission delay from the base station of the target cell to the UE is T2-T4-T3. Then the process of the first step is carried out,

ΔT＝T1-T2＝(t2-t1)–(t4-t3)＝(t3-t1)–(t4-t2)＝Td-Δt

here, Δ t is t4-t2, and may be calculated by the UE receiving DL signals transmitted by two cells.

The second method comprises the following steps: the TA is calculated based on the eNB.

The method for calculating the TA based on the eNB mainly comprises the steps that the UE is configured to send an uplink control signal in the switching process, and the base station estimates the TA according to the received uplink control signal.

Optionally, the uplink signal or the uplink channel includes one of: a channel Sounding Reference Signal (SRS), a non-contention Physical Random Access Channel (PRACH), or other uplink signals or channels.

Optionally, in a case that the uplink signal or the uplink channel is SRS or non-PRACH, the transmitting is performed according to a specific scheduleUE according to the timing advance value N of the source cell_TATo determine the transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

Optionally, when the first cell type and the second cell type are both source cells (corresponding to the technical solution of the first solution described above), before a user equipment UE is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the source cell; the UE determines the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the source cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a source cell and the second cell type is a target cell (corresponding to the second solution described above), before a UE is switched from the source cell to the target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the source cell;

the UE determines the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the target cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a target cell and the second cell type is a target cell (corresponding to the technical solution of the third solution method described above), before a UE is switched from a source cell to the target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the target cell;

Optionally, the performing, by the UE, timing adjustment according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell includes:

the TA command is calculated by the target cell according to the uplink signal or the uplink channel, wherein the target cell confirms a Handover Request acknowledgement or X2 sets a Response Setup Response to notify the TA command to the source cell through a Handover Request.

Optionally, the configuration information of the uplink signal or the uplink channel is configured in the following three ways:

the source cell is configured, wherein the source cell informs a target cell of the configuration through a Handover Request Handover Request or a Setup Request Setup Request set by X2; configuring a target cell; the source cell and the target cell negotiate a configuration.

Optionally, the first cell type and the second cell type both include: a source cell or a target cell; the UE determines the first cell type and the second cell type according to one of the following: and sending the notification message to the source cell according to the notification message or a preset rule.

In the technical solution described in the present application, there are three technical solutions, that is, the first to third solutions described above, and all the three methods can solve the technical solution proposed in the background art, specifically, which method is adopted by the UE to solve the technical problem, there are two ways to determine the two constraint ways for the constraint behavior of the UE described above, and the notification message in the above optional embodiment corresponds to the first solution described above, that is, the source cell notifies the UE through the higher layer signaling, MAC PDU/CE, or physical layer control signaling/downlink channel, and transmits the signal/channel according to which timing, and/or determines the uplink timing of the target cell according to which timing. Optionally, the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

The preset rule described in the above optional embodiment corresponds to the second constraint method, i.e. the predefined setting. The above constraint behavior is specified, for example, by a 3GPP standard protocol, and the UE determines from which timing the signal/channel is transmitted and/or from which timing the uplink timing of the target cell is determined, according to the specification predefined by the standard protocol. At this time, the source cell, the target cell and the UE are all clear of the constraint behavior or timing relationship, and therefore the UE does not need to be notified by the source cell.

Optionally, in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, and/or the timing advance value of the UE and the source cell remains unchanged, or the uplink timing relationship between the UE and the source cell remains unchanged. As described above, the method for the UE not to perform uplink timing adjustment with respect to the source cell is not limited to the case where the target cell calculates the TA command described in the present embodiment, and is also applicable to the case where the TA command is calculated by the UE.

Fig. 4 is a flowchart of a method for acquiring uplink timing applied to a source cell side according to an embodiment of the present invention, as shown in fig. 4, the steps are as follows:

s402, before User Equipment (UE) is switched from a source cell to a target cell, the source cell sends an uplink signal or configuration information of an uplink channel to the UE;

s404, the source cell receives the uplink signal or uplink channel sent by the UE, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

s406, the source cell sends a TA timing advance command to the UE, wherein the UE performs timing adjustment according to the received TA command, the downlink timing of the second cell and/or the current TA timing advance value of the source cell, and determines the uplink timing of the target cell through the timing adjustment, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type includes the source cell or the target cell.

Optionally, before the source cell sends the configuration information of the uplink signal or the uplink channel to the UE, the source cell notifies the target cell of the configuration information through a Handover Request or a Setup Request of X2.

Optionally, after the source cell receives the uplink signal or the uplink channel sent by the UE, the source cell notifies the target cell of the time information of receiving the uplink signal or the uplink channel, and/or the timing offset information between the source cell and the target cell.

Optionally, the source cell sends a notification message to the UE through a higher layer signaling, MAC PDU/CE, physical layer control signaling, or physical layer control downlink channel, where the notification message is used to set the first cell type and the second cell type. The above embodiments describe a first method for restricting which solution the UE adopts, and the source cell sends the notification message. Optionally, the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

Optionally, in the UE handover procedure, the source cell does not perform uplink timing related operation for the UE, where the operation includes: the source cell does not perform timing advance measurement of the UE, or the source cell does not send the TA command of the source cell to the UE, or the uplink timing relationship between the source cell and the UE remains unchanged. As described above, the method for the source cell not to perform uplink timing adjustment for the UE is not limited to the case where the target cell calculates the TA command described in the present embodiment, and is also applicable to the case where the TA command is calculated by the UE.

Fig. 5 is a flowchart of a method for acquiring uplink timing applied to a target cell side according to an embodiment of the present invention, as shown in fig. 5, the steps are as follows:

s502, before User Equipment (UE) is switched from a source cell to a target cell, the target cell receives an uplink signal or configuration information of an uplink channel sent by the source cell;

s504, the target cell calculates a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

s506, the target cell sends a TA timing advance command to the UE, wherein the UE determines the uplink timing of the target cell according to the received TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell, and the second cell type includes the source cell or the target cell.

Optionally, the sending, by the target cell, the timing advance TA command to the UE includes: the target cell confirms a Handover Request acknowledgement or an X2Setup Response to notify the TA command to the source cell through a Handover Request, wherein the source cell forwards the TA command to the UE.

Fig. 6 is a flowchart of a method for acquiring uplink timing according to an embodiment of the present invention, as shown in fig. 6, the steps are as follows:

s602, before a User Equipment (UE) is switched from a source cell to a target cell, the UE calculates a timing advance TA of the target cell according to a timing advance value of the source cell, a transmission delay difference of downlink signals sent by the source cell and the target cell simultaneously to the UE, and/or a timing deviation of the source cell and the target cell;

s604, the UE determines the uplink timing of the target cell through the TA.

Optionally, in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, or the timing advance value between the UE and the source cell remains unchanged, or the uplink timing relationship between the UE and the source cell remains unchanged. As described above, the method for the UE not to perform uplink timing adjustment with respect to the source cell is not limited to the case where the target cell calculates the TA command described in the present embodiment, and is also applicable to the case where the TA command is calculated by the UE.

Alternative embodiment of the invention (corresponding to the solution one described above)

In this embodiment, when the uplink signal or uplink channel to be transmitted is PRACH, the following steps are performed:

step one, a source cell configures UE to send PRACH and informs a target cell of the configuration. Alternatively, the above operation may occur before or during handover. Alternatively, the configuration may be notified to the target cell in the Handover Request or the X2Setup Request. The above-described method can also be used for determining the configuration and interacting between the source cell and the target cell, and this embodiment only takes the example of setting and notifying the source cell to the target cell/UE.

Before or during handover may also be described as before the user equipment UE is handed over from the source cell to the target cell. Both meanings are the same throughout this document.

And step two, the UE sends the PRACH based on the downlink timing of the source cell at the UE side according to the configuration sent by the source cell.

And step three, the source cell receives the PRACH and calculates a timing advance TA value. And transmits a timing advance command (TA command 1) of 11 bits to the UE. And/or the target cell receives the PRACH, calculates a timing advance TA value and sends a timing advance command (TA command2) of 11bit to the UE. The TA value calculated by the current cell is not actually the real timing relationship or timing advance relationship between the target cell and the UE, because the UE transmits the PRACH according to the downlink timing of the source cell, but not according to the downlink timing of the target cell. Alternatively, the TA command2 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

Step four, the UE receives the TA command sent by the source cell and/or the target cell, and executes timing adjustment based on the downlink timing of the source cell,to determine the uplink timing of the target cell. Before the switching is completed or the UE sends switching confirmation information, the UE calculates to obtain N according to the received TA command1 sent by the source cell_TAValues (see 3GPP Rel-1336.213, infra). And performs timing adjustment to determine the uplink timing of the source cell based on the downlink timing of the source cell (see 3GPP Rel-1336.211, infra). And the UE sends an uplink signal or a channel to the source cell according to the uplink timing. The UE calculates to obtain N according to the TA command2 calculated or sent by the received target cell_TAValue (3GPP Rel-1336.213, hereinafter), and performs timing adjustment based on the downlink timing of the source cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Alternative embodiment two of the present invention (corresponding to the second solution described above)

In this embodiment, when the uplink signal or the uplink channel to be transmitted is SRS or non-PRACH, the following steps are performed:

step one, a source cell configures UE to send SRS or other non-PRACH uplink signals or channels, and informs a target cell of the configuration. The following takes SRS as an example. Alternatively, the above operation may occur before or during handover. Alternatively, the configuration may be notified to the target cell in the Handover Request or the X2Setup Request. The above-described method can also be used for determining the configuration and interacting between the source cell and the target cell, and this embodiment only takes the example of setting and notifying the source cell to the target cell/UE.

And step two, the UE sends the SRS based on the downlink timing of the source cell at the UE side and/or the current timing advance value of the source cell according to the configuration of the source cell. Here, the downlink timing on the UE side based on the source cell includes the following cases: and on the basis of the downlink timing of the source cell at the UE side, determining the uplink sending timing according to the current timing advance value of the source cell. This current uplink transmission timing is also generated based on the downlink timing of the source cell on the UE side. The downlink timing of the source cell at the UE side and the current source cell timing advance value actually determine the uplink timing of the source cell at the UE side.

And step three, the source cell receives the SRS and calculates a timing advance TA value. And transmits a timing advance command (TA command 1) of 6 bits to the UE. And/or the target cell receives the SRS, calculates a timing advance TA value and sends a 6-bit timing advance command (TA command2) to the UE. The TA value calculated by the current cell is not actually the real timing or timing advance relationship between the target cell and the UE, because the UE transmits the SRS according to the downlink timing of the source cell, but not according to the downlink timing of the target cell. Alternatively, the TA command2 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step four, the UE receives the TA command sent by the source cell and/or the target cell, and executes timing adjustment based on the downlink timing of the source cell and/or the current timing advance value of the source cell to determine the uplink timing of the target cell. Before the switching is completed or the UE sends switching confirmation information, the UE sends TA command1 and the current timing advance value (N) according to the received source cell_TAValue) N_TA,oldCalculating to obtain new N_TAValue N_TA,new. And performing timing adjustment based on the downlink timing of the source cell to determine the uplink timing of the source cell. And the UE sends an uplink signal or a channel to the source cell according to the uplink timing. The UE sends TA command2 and current source cell N according to the received target cell_TAValue N_TA,oldCalculating to obtain new N_TAValue N_TA,new. And performing timing adjustment to determine the uplink timing of the target cell based on the downlink timing of the source cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Optionally, when the first cell is a source cell and the second cell is a target cell, the configuration information includes: the downlink timing of the source cell or the uplink timing of the source cell.

Optionally, the UE sends an uplink signal or an uplink channel to the target cell and/or the source cell based on the configuration information of the first cell, where the source cell notifies the target cell of the time information of receiving the uplink signal or the uplink channel, and/or the timing offset information between the source cell and the target cell.

Alternative embodiment three of the present invention (corresponding to the solution two described above)

This embodiment describes a case where the uplink signal or uplink channel transmitted in a scenario where a source cell and a target cell are synchronized is a PRACH, and the steps are as follows:

And step two, the UE sends the PRACH based on the downlink timing of the source cell at the UE side according to the configuration of the source cell.

Step three, the source cell receives the PRACH at the time of Ts; and/or the target cell receives the PRACH at the Tt moment; the source cell informs the target cell of the timing or time information of the received PRACH.

And step four, the target cell calculates a timing advance TA value according to the timing of receiving the PRACH and the timing of receiving the PRACH by the source cell. And transmits a timing advance command (TA command 1) of 11 bits to the UE. Specifically, if the target cell only receives the timing of the PRACH, the uplink timing adjustment amount corresponding to the TA command obtained by calculation is T. The corresponding TA command is T/(16 Ts). Ts is a timing unit defined in Rel-1336.211 and is equal to about 32.55 ns. Since the PRACH is based on the downlink timing transmission of the source cell, the actual timing advance offset of the target cell should also be subtracted by the path delay difference from the UE to both cells. The actual timing advance deviation should therefore be T' ═ T- (Ts-Tt). The actual TA command1 ═ T'/(16 × Ts). Alternatively, the TA command1 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step five, the UE receives the TA command1 calculated or sent by the target cell, and executes timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. The UE calculates N according to the received TA command1 of the target cell_TAValue (Rel-1336.213). And performing timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Alternative embodiment four of the invention (corresponding to the solution two described above)

This embodiment describes a case where the uplink signal or the uplink channel transmitted in the scenario of synchronization between the source cell and the target cell is SRS or non-PRACH, and the steps are as follows:

And step two, the UE sends the SRS based on the downlink timing of the source cell at the UE side and/or the current timing advance value of the source cell according to the configuration of the source cell. Including the following cases: and based on the downlink timing of the source cell at the UE side, transmitting the SRS according to the uplink transmission timing determined according to the current timing advance value. This current uplink transmission timing is also generated based on the downlink timing of the source cell on the UE side. The downlink timing of the source cell at the UE side and the current source cell timing advance value actually determine the uplink timing of the source cell at the UE side.

Step three, the source cell receives the SRS at the time Ts; and/or the target cell receives the SRS at the Tt moment; the source cell notifies the target cell of the timing or time information of the received SRS.

And step four, the target cell calculates a timing advance TA value according to the timing of receiving the SRS and the timing of receiving the SRS by the source cell. And transmits a timing advance command (TA command 1) of 6 bits to the UE. Specifically, if the target cell only receives the SRS at the timing, the uplink timing adjustment amount corresponding to the TA command is calculated to be T. The corresponding TAcommand ═ T/(16 × Ts). Ts is a timing unit defined in Rel-1336.211 and is equal to about 32.55 ns. Since SRS is transmitted based on the downlink timing of the source cell, the actual timing advance offset of the target cell should also be subtracted by the path delay difference between the UE and the two cells. The actual timing advance deviation should therefore be T' ═ T- (Ts-Tt). The actual TA command1 ═ T'/(16 × Ts). Alternatively, TA command1 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step five, the UE receives the TA command1 calculated or sent by the target cell, and performs timing adjustment based on the current timing advance value of the source cell and the downlink timing of the target cell to determine the uplink timing of the target cell. The UE carries out timing advance value (N) according to the TA command1 of the received target cell and the current source cell_TAValue) N_TA,oldCalculating to obtain new N_TAValue N_TA,new. And performing timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing. When UE executes the timing advance command of the target cell for the first time, the target cell does not have N currently_TAValue (or 0) and the previous SRS transmission is based on the downlink timing and/or uplink timing of the source cell, and thus is in accordance with the source cell N_TAValue N_TA,oldTo obtain new N_TAValue N_TA,newAnd performs timing adjustment. Then if the timing advance adjustment is executed again, the current N of the target cell is followed_TAValue N_TA,oldTo obtain new N_TA。

Alternative embodiment five of the invention (corresponding to the solution two described above)

This embodiment describes a case where the uplink signal or uplink channel sent in an asynchronous scenario between a source cell and a target cell is PRACH, and includes the following steps:

assuming that the timing offset of the target cell and the source cell is Td, as shown on the left side of fig. 3, Td is (t3-t 1).

Step three, the source cell receives the PRACH at the time of Ts; the target cell receives the PRACH at the time Tt; the source cell informs the target cell, e.g., Ts, of the timing or time information of receiving the PRACH. And/or the source cell informs the target cell of the timing deviation Td of the source cell and the target cell.

And step four, the target cell calculates the TA value of the timing advance according to the timing of receiving the PRACH, the timing of receiving the PRACH by the source cell and the timing deviation of the two cells. And transmits a timing advance command (TA command 1) of 11 bits to the UE. Specifically, if the target cell only receives the timing of the PRACH, the uplink timing adjustment amount corresponding to the TA command obtained by calculation is T. The corresponding TA command is T/(16 Ts). Ts is a timing unit defined in Rel-1336.211 and is equal to about 32.55 ns. Then the actual timing advance offset of the target cell should also take into account the path delay difference of the UE to the two cells and the timing offset of the two cells, since the PRACH is based on the downlink timing transmission of the source cell. The actual timing advance deviation should therefore be T' ═ T + Td- (Ts-Tt). The actual TA command1 ═ T'/(16 × Ts). Alternatively, TA command1 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step five, the UE receives the TA command1 sent by the target cell, and executes timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. The UE calculates N according to the received TA command1 sent by the target cell_TAValue (Rel-1336.213). And performing timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Alternative embodiment six of the invention (corresponding to the solution two described above)

This embodiment describes a case where the uplink signal or uplink channel transmitted in an asynchronous scenario between a source cell and a target cell is SRS or non-PRACH, and the steps are as follows:

And step two, the UE sends the SRS based on the downlink timing of the source cell at the UE side and/or the current timing advance value of the source cell according to the configuration of the source cell. Including the following cases: and based on the downlink timing of the source cell at the UE side, transmitting the SRS according to the uplink transmission timing determined by the current timing advance parameter. This current uplink transmission timing is also generated based on the downlink timing of the source cell on the UE side. The downlink timing of the source cell at the UE side and the current source cell timing advance value actually determine the uplink timing of the source cell at the UE side.

Step three, the source cell receives the SRS at the time Ts; and/or the target cell receives the SRS at the Tt moment; the source cell informs the target cell, e.g., Ts, of the timing or time information of the SRS reception. And/or the source cell informs the target cell of the timing deviation Td of the source cell and the target cell.

And step four, the target cell calculates the TA value of the timing advance according to the timing of receiving the SRS, the timing of receiving the SRS by the source cell and the timing deviation of the two cells. And transmits a timing advance command (TA command 1) of 6 bits to the UE. Specifically, if the target cell only receives the SRS at the timing, the uplink timing adjustment amount corresponding to the TA command is calculated to be T. The corresponding TA command is T/(16 Ts). Ts is a timing unit defined in Rel-1336.211 and is equal to about 32.55 ns. Then the actual timing advance offset of the target cell should also take into account the path delay difference of the UE to the two cells and the timing offset of the two cells, since the SRS is transmitted based on the downlink timing of the source cell. The actual timing advance deviation should therefore be T' ═ T + Td- (Ts-Tt). The actual TA command1 ═ T'/(16 × Ts). Alternatively, the TA command1 may be notified by the target cell to the source cell in the Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step five, the UE receives the TA command1 sent by the source cell and/or the target cell, and executes timing adjustment based on the downlink timing of the target cell and the current timing advance value of the source cell to determine the uplink timing of the target cell. The UE sends TA command1 and the current timing advance value (N) of the source cell according to the received target cell_TAValue) N_TA,oldCalculating to obtain new N_TAValue N_TA,new. And performing timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing. The first time the UE executes the timing advance command of the target cell,since the target cell does not currently have N_TAValue (or 0) and the previous SRS transmission is based on the downlink timing and/or uplink timing of the source cell, and thus is in accordance with the source cell N_TAValue N_TA,oldTo obtain new N_TAValue N_TA,newAnd performs timing adjustment. Then if the timing advance adjustment is executed again, the current N of the target cell is followed_TAValue N_TA,oldTo obtain new N_TA。

Optionally, when the first cell and the second cell are both target cells, the configuration information includes: the downlink timing of the source cell or the uplink timing of the source cell.

Optionally, the performing, by the UE, timing adjustment according to the received timing advance TA command and the downlink timing of the second cell includes: the TA command is calculated by the target cell according to the uplink signal or the uplink channel, wherein the target cell notifies the TA command to the source cell through a Handover Request or an X2Setup Request.

Alternative embodiment seven of the invention (corresponding to the solution three described above)

This embodiment is a case where the uplink signal or the uplink channel to be transmitted is the PRACH according to the above optional embodiments, and includes the following steps:

And step two, the UE sends PRACH based on the downlink timing of the target cell at the UE side according to the configuration sent by the source cell.

And step three, the target cell receives the PRACH, calculates a timing advance TA value and sends a timing advance command (TA command 1) of 11 bits to the UE. Alternatively, the TA command1 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step four, the UE receives the TA command1 of the target cell and executes timing adjustment to determine the uplink timing of the target cell based on the downlink timing of the target cell. The UE calculates to obtain N according to the received TA command1 calculated or sent by the target cell_TAValue (3GPP Rel-1336.213, hereinafter), and performs timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Alternative embodiment eight of the invention (corresponding to the solution three described above)

This embodiment is a case where the uplink signal or the uplink channel to be transmitted is SRS or non-PRACH according to the above optional embodiments, and includes the following steps:

And step two, the UE sends the SRS based on the downlink timing of the target cell at the UE side and/or the timing advance value of the current source cell according to the configuration sent by the source cell. And on the basis of the downlink timing of the target cell at the UE side, transmitting the SRS according to the uplink transmission timing determined by the timing advance value of the current source cell.

And step three, the target cell receives the SRS, calculates a timing advance TA value and sends a 6-bit timing advance command (TA command 1) to the UE. Alternatively, the TA command1 may be notified by the target cell to the source cell in a Handover Request acknowledgement or X2Setup Response, and notified by the source cell to the UE.

And step four, the UE receives the TA command1 calculated or sent by the target cell, and executes timing adjustment based on the downlink timing of the target cell and the timing advance value of the current source cell to determine the uplink timing of the target cell. The UE calculates or sends TA command1 and current source cell N according to the received target cell_TAValue N_TA,oldCalculating to obtain new N_TAValue N_TA,new. And performing timing adjustment based on the downlink timing of the target cell to determine the uplink timing of the target cell. During or after the handover, the UE transmits an uplink signal or channel to the target cell according to the uplink timing.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

Example 2

In this embodiment, an uplink timing obtaining apparatus is further provided, which is applied to a user equipment UE, and is used to implement the foregoing embodiments and preferred embodiments, and details of which have been already described are omitted. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Fig. 7 is a block diagram of an apparatus for acquiring uplink timing applied to a UE according to an embodiment of the present invention, and as shown in fig. 7, the apparatus includes:

a first sending module 72, configured to obtain configuration information of an uplink signal or an uplink channel before a user equipment UE is switched from a source cell to a target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell;

a first determining module 74, connected to the first sending module 72, configured to determine the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell.

Optionally, in a case that the uplink signal or the uplink channel is SRS or non-PRACH, the first sending module 72 is further configured to advance the value N according to the timing of the source cell_TATo determine the transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

Optionally, in case that the first cell type and the second cell type are both source cells, characterized in that,

the first sending module 72 is further configured to, before the UE is switched from the source cell to the target cell, obtain configuration information of an uplink signal or an uplink channel, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the source cell;

the first determining module 74 is further configured to determine the uplink timing of the target cell by the UE according to the received timing advance TA command, the downlink timing of the source cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, in case the first cell type is a source cell and the second cell type is a target cell, characterized in that,

the first determining module 74 is further configured to determine the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the target cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

Optionally, when the first cell type is a target cell and the second cell type is a target cell, the first sending module 72 is further configured to obtain configuration information of an uplink signal or an uplink channel before the UE is switched from the source cell to the target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the target cell;

Optionally, in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes:

the UE does not perform the timing advance command sent by the source cell and/or the timing advance value of the UE and the source cell remains unchanged.

Fig. 8 is a block diagram of an apparatus for acquiring uplink timing applied to a source cell according to an embodiment of the present invention, and as shown in fig. 8, the apparatus includes:

a second sending module 82, configured to send an uplink signal or configuration information of an uplink channel to the UE before the UE is switched from the source cell to the target cell;

a first receiving module 84, connected to the second sending module 82, configured to receive the uplink signal or the uplink channel sent by the UE, where the uplink signal or the uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

a third sending module 86, connected to the first receiving module 84, configured to send a timing advance TA command to the UE, where the UE performs timing adjustment according to the received TA command, downlink timing of the second cell and/or a current timing advance value of the source cell, and determines uplink timing of the target cell through the timing adjustment, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type includes the source cell or the target cell.

Optionally, the first receiving module 84 is further configured to, after the source cell receives the uplink signal or the uplink channel sent by the UE, notify the target cell of the time information of receiving the uplink signal or the uplink channel, and/or the timing offset information of the source cell and the target cell.

Optionally, the source cell sends a notification message to the UE through a higher layer signaling, MAC PDU/CE, physical layer control signaling, or physical layer control downlink channel, where the notification message is used to set the first cell type and the second cell type.

Optionally, in the UE handover procedure, the source cell does not perform uplink timing related operation for the UE, where the operation includes: the source cell does not perform timing advance measurements for the UE, or the source cell does not send the TA command of the source cell to the UE.

Fig. 9 is a block diagram of an apparatus for acquiring uplink timing applied to a target cell according to an embodiment of the present invention, and as shown in fig. 9, the apparatus includes:

a second receiving module 92, configured to receive an uplink signal or configuration information of an uplink channel sent by a source cell before a user equipment UE is switched from the source cell to a target cell;

a processing module 94, connected to the second receiving module 92, configured to calculate a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

a fourth sending module 96, connected to the processing module 94, configured to send a timing advance TA command to the UE, where the UE performs timing adjustment according to the received TA command, downlink timing of the second cell and/or a current timing advance value of the source cell, and determines uplink timing of the target cell through the timing adjustment, where the second cell type includes the source cell or the target cell.

Optionally, the fourth sending module 96 is further configured to notify the TA command to the source cell by a Handover Request acknowledgement (Handover Request Acknowledge) or a Setup Response (Setup Response) of X2, where the TA command is forwarded to the UE by the source cell.

Fig. 10 is a block diagram of an apparatus for acquiring uplink timing according to an embodiment of the present invention, which is applied to a UE, and as shown in fig. 10, the apparatus includes:

a calculating module 1002, configured to calculate, before a UE is switched from a source cell to a target cell, a timing advance TA of the target cell according to a timing advance value of the source cell, a transmission delay difference between downlink signals simultaneously sent by the source cell and the target cell and arriving at the UE, and/or a timing offset between the source cell and the target cell;

a second determining module 1004, connected to the calculating module 1002, is configured to determine the uplink timing of the target cell through the TA.

Optionally, the apparatus further comprises: in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes: the UE does not execute the timing advance command sent by the source cell, or the timing advance value between the UE and the source cell remains unchanged, or the uplink timing relationship between the UE and the source cell remains unchanged.

It should be noted that, the above modules may be implemented by software or hardware, and for the latter, the following may be implemented, but not limited to: the modules are all positioned in the same processor; alternatively, the modules are respectively located in different processors in any combination.

Example 3

The embodiment of the invention also provides a storage medium. Alternatively, in the present embodiment, the storage medium may be configured to store program codes for performing the following steps:

s1, before UE is switched from source cell to target cell, the UE obtains configuration information of uplink signal or uplink channel, and the UE sends the uplink signal or uplink channel to the target cell and/or the source cell based on the downlink timing of the first cell;

s2, the UE determines the uplink timing of the target cell according to the received TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell.

The storage medium may be configured to store program code for performing the steps of:

s1, before user equipment UE is switched from a source cell to a target cell, the source cell sends uplink signals or configuration information of uplink channels to the UE;

s2, the source cell receives the uplink signal or uplink channel sent by the UE, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

s3, the source cell sends a TA command to the UE, wherein the UE performs timing adjustment according to the received TA command, the downlink timing of the second cell and/or the current TA value of the source cell, and determines the uplink timing of the target cell through the timing adjustment, wherein the TA command is calculated by the target cell according to the uplink signal or uplink channel; the second cell type includes the source cell or the target cell.

s1, before the UE is switched from the source cell to the target cell, the target cell receives the uplink signal or the configuration information of the uplink channel sent by the source cell;

s2, the target cell calculates a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

s3, the target cell sends a TA timing advance command to the UE, wherein the UE performs timing adjustment according to the received TA command, downlink timing of the second cell and/or a current TA value of the source cell, and determines uplink timing of the target cell through the timing adjustment, wherein the type of the second cell includes the source cell or the target cell.

Optionally, in this embodiment, the storage medium may include, but is not limited to: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

Optionally, in this embodiment, the processor executes the method steps described in the above embodiments according to the program code stored in the storage medium.

Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and this embodiment is not described herein again.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for acquiring uplink timing is characterized by comprising the following steps:

before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of a first cell;

the UE determines uplink timing of the target cell according to a received Timing Advance (TA) command, downlink timing of a second cell and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell;

in the UE handover procedure, the UE does not perform an operation of uplink timing adjustment for the source cell, where the operation includes:

the UE does not execute the timing advance command sent by the source cell, or the timing advance value of the UE and the source cell is kept unchanged, or the uplink timing relation of the UE and the source cell is kept unchanged.

2. The method of claim 1, wherein the uplink signal or uplink channel comprises one of: a channel Sounding Reference Signal (SRS), a Physical Random Access Channel (PRACH), or other uplink signals or uplink channels.

3. The method of claim 1, wherein in case that the uplink signal or the uplink channel is SRS or non-PRACH, the method further comprises:

the UE advances value N according to the timing of the source cell_TATo determine a transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

4. The method according to claim 1, wherein in case that the first cell type and the second cell type are both source cells, the method comprises:

before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of the source cell;

and the UE determines the uplink timing of the target cell according to the received Timing Advance (TA) command, the downlink timing of the source cell and/or the current timing advance value of the source cell, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

5. The method according to claim 1, wherein in case that the first cell type is a source cell and the second cell type is a target cell, the method comprises:

and the UE determines the uplink timing of the target cell according to the received Timing Advance (TA) command, the downlink timing of the target cell and/or the current timing advance value of the source cell, wherein the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

6. The method according to claim 1, wherein in case that the first cell type is a target cell and the second cell type is a target cell, the method comprises:

before User Equipment (UE) is switched from a source cell to a target cell, the UE acquires configuration information of an uplink signal or an uplink channel, and the UE sends the uplink signal or the uplink channel to the target cell and/or the source cell at a fixed time based on downlink of the target cell;

7. The method of claim 1, wherein the UE determining the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell comprises:

the TA command is calculated by the target cell according to the uplink signal or the uplink channel, and the target cell notifies the TA command to the source cell by confirming a Handover request acknowledgement or setting a Response Setup Response by X2.

8. The method of claim 1, wherein the configuration information of the uplink signal or the uplink channel is configured by one of the following three ways:

the source cell is configured, wherein the source cell informs a target cell of the configuration through a Handover Request Handover Request or a Setup Request of X2; configuring a target cell; and the source cell and the target cell negotiate configuration.

9. The method of claim 1, wherein the first cell type and the second cell type each comprise: a source cell or a target cell;

the UE determines the first cell type and the second cell type in one of the following ways: and sending the notification message to the source cell according to the notification message or a preset rule.

10. The method according to claim 9, wherein the notification message is carried in a handover command sent by the source cell to the UE, or carried in the configuration information of the uplink signal or the uplink channel, or sent together with the configuration information of the uplink signal or the uplink channel.

11. A method for acquiring uplink timing is characterized by comprising the following steps:

before User Equipment (UE) is switched from a source cell to a target cell, the source cell sends an uplink signal or configuration information of an uplink channel to the UE;

the source cell receives the uplink signal or the uplink channel sent by the UE, wherein the uplink signal or the uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

the source cell sends a Timing Advance (TA) command to the UE, wherein the UE determines uplink timing of the target cell according to the received TA command, downlink timing of a second cell and/or a current timing advance value of the source cell, and the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type comprises the source cell or the target cell;

in the UE switching process, the source cell does not execute uplink timing related operation aiming at the UE, wherein the operation comprises the following steps: the source cell does not perform timing advance measurement of the UE, or the source cell does not send a TA command of the source cell to the UE, or the uplink timing relationship between the source cell and the UE remains unchanged.

12. The method of claim 11, before the source cell sends the configuration information of the uplink signal or the uplink channel to the UE, comprising:

and the source cell informs the configuration information to the target cell through a Handover Request Handover Request or a Setup Request of X2.

13. The method according to claim 11, wherein after the source cell receives the uplink signal or uplink channel transmitted by the UE, the source cell notifies the target cell of the time information of receiving the transmitted uplink signal or uplink channel and/or the timing offset information between the source cell and the target cell.

14. The method of claim 11, wherein the source cell sends a notification message to the UE through higher layer signaling, MAC PDU/CE, physical layer control signaling or physical layer control downlink channel, wherein the notification message is used to set the first cell type and the second cell type.

15. The method according to claim 14, wherein the notification message is carried in a handover command sent by the source cell to the UE, or carried in or sent together with the configuration information of the uplink signal or the uplink channel.

16. A method for acquiring uplink timing is characterized by comprising the following steps:

before User Equipment (UE) is switched from a source cell to a target cell, the target cell receives an uplink signal or configuration information of an uplink channel sent by the source cell;

the target cell calculates a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

the target cell sends a Timing Advance (TA) command to the UE, wherein the UE determines uplink timing of the target cell according to the received TA command, downlink timing of a second cell and/or a current timing advance value of the source cell, wherein the type of the second cell comprises the source cell or the target cell;

in the UE handover process, the timing advance value of the UE and the source cell remains unchanged, or the uplink timing relationship between the UE and the source cell remains unchanged.

17. The method of claim 16, wherein the target cell sending a Timing Advance (TA) command to the UE comprises:

and the target cell confirms a Handover Request acknowledgement or an X2set Response Setup Response through a Handover Request to inform the TA command to the source cell, wherein the source cell forwards the TA command to the UE.

18. An apparatus for acquiring uplink timing, applied to a UE, includes:

a first sending module, configured to obtain configuration information of an uplink signal or an uplink channel before a user equipment UE is switched from a source cell to a target cell, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of a first cell;

a first determining module, configured to determine uplink timing of the target cell according to a received Timing Advance (TA) command, downlink timing of a second cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or uplink channel, the first cell type includes the source cell or the target cell, and the second cell type includes the source cell or the target cell;

19. The apparatus of claim 18, wherein the uplink signal or uplink channel comprises one of: a channel Sounding Reference Signal (SRS), a Physical Random Access Channel (PRACH), or other uplink signals or channels.

20. The apparatus of claim 18, wherein the first transmitting module is further configured to advance N according to the timing advance value of the source cell when the uplink signal or the uplink channel is SRS or non-PRACH_TATo determine a transmission time instant for transmitting the uplink signal or uplink channel to the target cell and/or the source cell.

21. The apparatus of claim 18, wherein in case both the first cell type and the second cell type are source cells,

the first sending module is further configured to, before the UE is switched from the source cell to the target cell, obtain configuration information of an uplink signal or an uplink channel, and send the uplink signal or the uplink channel to the target cell and/or the source cell at a downlink timing based on the source cell;

the first determining module is further configured to determine uplink timing of the target cell according to a received timing advance TA command, downlink timing of a source cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

22. The apparatus of claim 18, wherein in the case that the first cell type is a source cell and the second cell type is a target cell,

the first determining module is further configured to determine uplink timing of the target cell according to a received timing advance TA command, downlink timing of the target cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel.

23. The apparatus of claim 18, wherein in the case that the first cell type is a target cell and the second cell type is a target cell,

the first sending module is further configured to, before the UE is switched from the source cell to the target cell, obtain configuration information of an uplink signal or an uplink channel, and send the uplink signal or the uplink channel to the target cell and/or the source cell based on downlink timing of the target cell;

24. The apparatus of claim 18, wherein the UE determines the uplink timing of the target cell according to the received timing advance TA command, the downlink timing of the second cell and/or the current timing advance value of the source cell comprises:

25. The apparatus of claim 18, wherein the configuration information of the uplink signal or the uplink channel is configured by three methods:

26. The apparatus of claim 18, wherein the first cell type and the second cell type each comprise: a source cell or a target cell;

27. The apparatus of claim 26, wherein the notification message is carried in a handover command sent by the source cell to a UE, or carried in or sent together with configuration information of the uplink signal or uplink channel.

28. An uplink timing acquisition device applied to a source cell, comprising:

a second sending module, configured to send an uplink signal or configuration information of an uplink channel to the UE before the UE is switched from the source cell to the target cell;

a first receiving module, configured to receive the uplink signal or the uplink channel sent by the UE, where the uplink signal or the uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

a third sending module, configured to send a Timing Advance (TA) command to the UE, where the UE determines uplink timing of the target cell according to the received TA command, downlink timing of the second cell, and/or a current timing advance value of the source cell, where the TA command is calculated by the target cell according to the uplink signal or the uplink channel; the second cell type comprises the source cell or the target cell;

29. The apparatus of claim 28, wherein before the source cell sends the configuration information of the uplink signal or uplink channel to the UE, the source cell notifies the target cell of the configuration information through a Handover Request or a Setup Request X2.

30. The apparatus of claim 28, wherein the first receiving module is further configured to notify the target cell of time information of receiving the uplink signal or the uplink channel sent by the UE and/or timing offset information of the source cell and the target cell after the source cell receives the uplink signal or the uplink channel sent by the UE.

31. The apparatus of claim 28, wherein the source cell sends a notification message to the UE through higher layer signaling, MAC PDU/CE, physical layer control signaling or physical layer control downlink channel, wherein the notification message is used to set the first cell type and the second cell type.

32. The apparatus of claim 31, wherein the notification message is carried in a handover command sent by the source cell to a UE, or carried in or sent together with configuration information of the uplink signal or the uplink channel.

33. An apparatus for acquiring uplink timing, applied to a target cell, includes:

a second receiving module, configured to receive an uplink signal or configuration information of an uplink channel sent by a source cell before a user equipment UE is switched from the source cell to a target cell;

a processing module, configured to calculate a TA command according to the received uplink signal or uplink channel, where the uplink signal or uplink channel is sent by the UE based on downlink timing of a first cell, and the first cell type includes the source cell or the target cell;

a fourth sending module, configured to send a Timing Advance (TA) command to the UE, where the UE determines uplink timing of the target cell according to the received TA command, downlink timing of a second cell and/or a current timing advance value of the source cell, where the second cell type includes the source cell or the target cell;