Abstract:
A cell deployment method and device for replacing PCells, used for enabling PCell replacement in a carrier aggregation system. Said method comprises: a User Equipment (UE) obtains PCell and SCell deployment information via a PCell replacement command; UE obtains target PCell and target SCell deployment information by combining the obtained PCell and SCell deployment information with saved original PCell and SCell deployment information, and hands over from the original PCell and original SCell to the target PCell and target SCell. A device used to carry out the method is also disclosed.

Description:
[0001]    This application claims the benefit of Chinese Patent Application No. 201010251151.6, filed with the Chinese Patent Office on Aug. 11, 2010 and entitled “Cell configuration method and apparatus for changing primary cell”, which is hereby incorporated by reference in its entirety. 
       FIELD 
       [0002]    The present invention relates to the field of communications and particularly to a cell configuration method and apparatus for changing a primary cell 
       BACKGROUND 
       [0003]    There is only one carrier in a cell in Long Term Evolution (LTE) and earlier radio communication systems, and the maximum bandwidth in the LTE system is 20 MHz. A Long Term Evolution-Advanced (LTE-A) system has been proposed in the industry for an improved transmission bandwidth, 
         [0004]    Peak rates of the LTE-A system, which requires 1 Gbps in the downlink and 500 Mbps in the uplink, are greatly improved than that of the LTE system. In the LTE-A system, the required peak rates can not be reached by using only one carrier with the maximum bandwidth of 20 MHz. Thus the LTE-A system has to extend a bandwidth available to a user equipment, and to this end, Carrier Aggregation (CA) has been introduced, that is, a plurality of consecutive or inconsecutive carriers under the same Evolved NodeB (eNB) are aggregated together to serve a User Equipment (UE) concurrently, thereby providing the required rates. These carriers aggregated together are also referred to as Component Carriers (CCs). Each cell can be a component carrier, and cells (component carriers) under different eNB can not be aggregated. The concepts of a primary cell (Pcell) and a secondary (Scell) have been defined among a plurality of cells aggregated for a UE and correspond respectively to a primary carrier cell and a secondary carrier cell currently aggregated for the UE. 
         [0005]    The LTE system is a single-carrier system and involves configuration of only one target cell during handover. The LTE-A system involves handover of a plurality of cells including a primary carrier cell and a secondary carrier cell and can not directly continue the use of a handover process of the LTE system, and an effective solution to a handover process in the LTE-A system has been absent so far. 
       SUMMARY 
       [0006]    Embodiments of the invention provide a cell configuration method and apparatus for changing a primary cell to enable change of a primary cell in a carrier aggregation system. 
         [0007]    A cell configuration method for changing a primary cell, applicable to the UE side, includes: 
         [0008]    a User Equipment, UE, obtaining configuration information of a primary cell and a secondary cell(s) from a primary cell change command; and 
         [0009]    the UE obtaining configuration information of a target primary cell and a target secondary cell(s) from the obtained configuration information of the primary cell and the secondary cell(s) in combination with stored configuration information of a source primary cell and a source secondary cell(s) and changing from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0010]    A cell configuration method for changing a primary cell, applicable to the base station side to instruct a UE to update cells, includes: 
         [0011]    a base station generating a primary cell change command including configuration information of a primary cell; and 
         [0012]    the base station transmitting the primary cell change command to the User Equipment, UE, to instruct the UE to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and a secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0013]    A user equipment includes: 
         [0014]    an interface module configured to obtain configuration information of a primary cell and a secondary cell(s) from a primary cell change command; and 
         [0015]    a configuration module configured to obtain configuration information of a target primary cell and a target secondary cell(s) from the obtained configuration information of the primary cell and the secondary cell(s) in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0016]    A base station includes: 
         [0017]    a control module configured to generate a primary cell change command including configuration information of a primary cell; and 
         [0018]    an interface module configured to transmit the primary cell change command to a User Equipment, UE, to instruct the UE to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and a secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0019]    In the embodiments of the invention, a UE stores configuration information of a source primary cell and a source secondary cell(s) instead of deleting the configuration information of the source primary cell and the source secondary cell(s) immediately upon reception of a primary cell change command and then executes the primary cell change command by updating the stored configuration information of the source primary cell with configuration information of a primary cell carried in the primary cell change command and changing from the source primary cell to a target primary cell to thereby enable handover of the primary cell in an LTE-A system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a structural diagram of a communication system in an embodiment of the invention; 
           [0021]      FIG. 2  is a general structural diagram of a UE in an embodiment of the invention; 
           [0022]      FIG. 3  is a detailed structural diagram of a UE in an embodiment of the invention; 
           [0023]      FIG. 4  is a structural diagram of a base station in an embodiment of the invention; 
           [0024]      FIG. 5  is a flow chart of a method for cell handover at the UE side in an embodiment of the invention; 
           [0025]      FIG. 6  is a flow chart, of a method for cell handover at the base station side in an embodiment of the invention; 
           [0026]      FIG. 7  is a flow chart of a cell configuration method for changing a primary cell when a primary cell change command includes a deletion instruction and an addition instruction and the deletion instruction and the addition instruction include the same cell index in an embodiment of the invention; 
           [0027]      FIG. 8  is a flow chart of a cell configuration method for changing a primary cell when a primary cell change command includes a deletion instruction and an addition instruction and the deletion instruction and the addition instruction include different cell indexes in an embodiment of the invention; 
           [0028]      FIG. 9  is a flow chart of a cell configuration method for changing a primary cell when a primary cell change command includes a change instruction and there is an unchanged correspondence relationship between a cell and a cell index in an embodiment of the invention; 
           [0029]      FIG. 10  is a flow chart of a cell configuration method for changing a primary cell when a primary cell change command includes a change instruction and there is an unchanged correspondence relationship between a primary cell and a cell index in an embodiment of the invention; and 
           [0030]      FIG. 11  is a flow chart of a cell configuration method for changing a primary cell across base stations in an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0031]    In an embodiment of the invention, a UE stores configuration information of a source primary cell and a source secondary cell(s) instead of deleting the configuration information of the source primary cell and source secondary cell(s) immediately upon reception of a primary cell change command and then executes the primary cell change command by updating the stored configuration information of the source primary cell with, configuration information of a primary cell carried in the primary cell change command and changing from the source primary cell to a target primary cell to thereby enable handover of the primary cell in an LTE-A system. 
         [0032]    Referring to  FIG. 1 , a communication system in this embodiment includes a base station and a UE. The base station may be an eNB, a NodeB, etc. 
         [0033]    The base station is configured to generate a primary cell change command including configuration information of a primary cell and to transmit the primary cell change command to the UE to instruct the UE to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and a secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0034]    The primary cell change command may be embodied in various forms, and handover of a primary cell and/or a secondary cell may be implemented in various ways, for example, the primary cell change command includes a deletion instruction (release or remove) and an addition instruction; and the base station transmits the primary cell change command to the UE to instruct the UE to delete a cell index included in the deletion instruction and configuration information corresponding to the cell index and to add a cell index included in the addition instruction and configuration information, carried in the primary cell change command, corresponding to the cell index. Particularly, when the deletion instruction and the addition instruction includes the same cell index, the base station transmits the primary cell change command to the UE to instinct the UE to firstly delete the cell index and the configuration information corresponding to the cell index in response to the deletion instruction and then add the cell index and the configuration information, carried in the primary cell change command, corresponding to the cell index in response to the addition instruction. Alternatively, for example, the primary cell change command includes a change instruction; and the base station transmits the primary cell change command to the UE to instruct the UE to delete configuration information corresponding to a cell index included in the change instruction and to add configuration information, carried in the primary cell change command, corresponding to the cell index. Particularly the configuration information of the primary cell and the secondary cell(s) carried in the primary cell change command is delta configuration information or full configuration information relative to the stored configuration information of the source primary cell. Alternatively the configuration information of the primary cell carried in the primary cell change command is delta configuration information or full configuration information relative to the stored configuration information of the source primary cell, and the configuration information of the secondary cell(s) carried in the primary cell change command is delta configuration information or full configuration information relative to the stored configuration information of the source secondary cell(s). The foregoing deletion instruction, addition instruction and change instruction may be used to only change a secondary cell(s). To change a primary cell, the primary cell change command may carry only a cell index and configuration information of the target primary cell but none of the corresponding deletion instruction, addition instruction and change instruction. The UE configures the target primary cell directly in response to the primary cell change command and then deletes the configuration information of the source primary cell (updates the configuration information) automatically. 
         [0035]    The primary cell change command is a reconfiguration message (e.g., a Radio Resource Control (RRC) reconfiguration message); or the primary cell change command is a handover command. 
         [0036]    A cell index may be at a UE level, that is, different UEs corresponding to the same cell may be provided with different cell indexes. At present, the number of cells that can be aggregated for a UE is 5, and 3 bits may suffice to represent a cell index. 
         [0037]    Full configuration refers to that the base station transmits full configuration information to the UE in dedicated signaling, and the UE enables the configuration directly; and delta configuration refers to that both the UE and the base station stores the same set of old configuration internally, and then the base station transmits parameters different from the old configuration to the UE in dedicated signaling, and the UE enables directly the new configuration transmitted from the base station while continuing the use of or releasing the old configuration (and corresponding functions) for those parameters absent in the signaling. With the delta configuration scheme, the size of the dedicated signaling can be reduced and an overhead of the signaling can be lowered. 
         [0038]    Configuration information of a cell as a primary cell includes at least one of the following parameters: a relevant parameter of a Physical Uplink Control Channel (PUCCH), e.g., an Schedule Request (SR) resource; a relevant parameter of Semi-Persistent Scheduling (SPS), e.g., SPS resource configuration; a relevant parameter of a periodical Channel Quality-Indicator (CQI); a relevant parameter of a random access, e.g., allocation of a random access preamble; a relevant parameter of a radio link failure, e.g., a relevant counter and the length of the counter; a part of parameters in system information, e.g., the cycle of the system information, the size of a reception window of the system information, a Tracking Area Index (TAI), etc.; and the configuration information of the primary cell can further include other parameters which will not be enumerated here. 
         [0039]    Configuration information of a cell as a secondary cell includes an inactivated timer, etc. The configuration information of the secondary cell can further include other parameters which will not be enumerated here. 
         [0040]    The UE is configured to store instead of deleting immediately the configuration information of the source primary cell and the source secondary cell(s) upon reception of the primary cell change command, and then the UE obtains the configuration information of the target primary cell and the target secondary cell(s) from the configuration information of the primary cell and the secondary cell(s) carried in the primary cell change command in combination with the stored configuration information of all of the source primary cell and the source secondary cell(s) and changes from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). The primary cell change command may be embodied in various forms, and a primary and/or secondary cell handover may be implemented in various ways, for example, the primary cell change command includes a deletion instruction and an addition instruction; and the UE deletes a cell index included in the deletion instruction and configuration information corresponding to the cell index and adds a cell index included in the addition instruction and configuration information, carried in the primary cell change command, corresponding to the cell index. Particularly, when the deletion instruction and the addition instruction includes the same cell index, the UE firstly deletes the cell index and the configuration information corresponding to the cell index in response to the deletion instruction and then adds the cell index and the configuration information, carried in the primary cell change command, corresponding to the cell index in response to the addition instruction. Alternatively, for example, the primary cell change command includes a change instruction; and the UE deletes configuration information corresponding to a cell index included in the change instruction and adds configuration information, carried in the primary cell change command, corresponding to the cell index. The UE fetches system information of the target cell after updating the configuration information to thereby finish handover. The foregoing deletion instruction, addition instruction and change instruction can be used to only change a secondary cell(s). To change a primary cell, the primary cell change command may carry only a cell index and configuration information of a target primary cell but none of the corresponding deletion instruction, addition instruction and change instruction. The UE configures the target primary cell directly in response to the primary cell change command and then deletes configuration information of a source primary cell (updates the configuration information) automatically. 
         [0041]    Primary cell handover may be handover in a base station or across base stations. In the case of handover in a base station, then the same base station both decides handover and generates the primary cell change command. In the case of handover across base stations, then a source base station decides handover and transmits to a target base station a handover request carrying configuration information of a source primary cell and/or a source secondary cell(s), and the target base station generates a primary cell change command and transmits the primary cell change command to the UE via the source base station. In the case of handover across base stations, the UE fetches system information of the target cell to thereby establish a connection with the target base station and finish handover. 
         [0042]    Referring to  FIG. 2 , a UE in this embodiment includes an interface module  201  and a configuration module  202 . The interface module  201  may include a transceiver and other devices. The configuration module  202  may be embodied in various executable devices. 
         [0043]    The interface module  201  is configured to receive and parse a primary cell change command and to obtain configuration information of a primary cell and a secondary cell(s) carried therein from the primary cell change command. The interface module  201  is further configured to fetch system information of a target cell, etc. The interface module  201  may-further receive and transmit other messages. 
         [0044]    The configuration module  202  is connected with the interface module  201  and configured to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and the secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). When the primary cell change command includes a deletion instruction and an addition instruction, the configuration module  202  deletes a cell index included in the deletion instruction and configuration information corresponding to the cell index and adds a cell index included in the addition instruction and configuration information, carried in the primary cell change command, corresponding to the cell index. Particularly, when the deletion instruction and the addition instruction includes the same cell index, the configuration module  202  firstly deletes the cell index and the configuration information corresponding to the cell index in response to the deletion instruction and then adds the cell index and the configuration information, carried in the primary cell change command, corresponding to the cell index in response to the addition instruction. When the primary cell change command includes a change instruction, the configuration module  202  deletes configuration information corresponding to a cell index included in the change instruction and adds configuration information, carried in the primary cell change command, corresponding to the cell index. 
         [0045]    Referring to  FIG. 3 , the UE further includes a storage module  203  which can be embodied in various storage mediums. The storage module  203  is configured to save the configuration information of the source primary cell and the source secondary cell(s), etc. 
         [0046]    Referring to  FIG. 4 , a base station in this embodiment includes a control module  401  and an interface module  402 . The control module  401  can be embodied in various executable devices. The interface module  402  can be embodied in a transmitter and a receiver, etc. 
         [0047]    The control module  401  is configured to generate a primary cell change command including configuration information of a primary cell. The control module  401  is further configured to make a handover decision. 
         [0048]    The interface module  402  is configured to transmit the primary cell change command to a UE to instruct the UE to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and a secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). When the primary cell change command generated by the control module  401  includes a deletion instruction and an addition instruction; the interface module  402  transmits the primary cell change command to the UE to instruct the UE to delete a cell index included in the deletion instruction and configuration information corresponding to the cell index and to add a cell index included in the addition instruction and configuration information, carried in the primary cell change command, corresponding to the cell index. Particularly, when the deletion instruction and the addition instruction includes the same cell index, the interface module  402  transmits the primary cell change command to the UE to instruct the UE to firstly delete the cell index and the configuration information corresponding to the cell index in response to the deletion instruction and then add the cell index and the configuration information, carried in the primary cell change command, corresponding to the cell index in response to the addition instruction. When the primary cell change command generated by the control module  401  includes a change instruction, the interface module  402  transmits the primary cell change command to the UE to instruct the UE to delete configuration information corresponding to a cell index included in the change instruction and to add configuration information, carried in the primary cell change command, corresponding to the cell index. The interface module  402  is further configured to transmit and receive a handover request. 
         [0049]    The base station includes all of functions of being a source base station and a target base station and it plays of different roles in different scenarios. 
         [0050]    The internal structures and functions of the communication system, the base station and the UE have been described above, and a process of cell handover will be described below. 
         [0051]    Referring to  FIG. 5 , a flow chart of a method for cell handover at the UE side in this embodiment is as follows: 
         [0052]    Operation  501 : A UE stores configuration information of a source primary cell and a source secondary cell(s) upon reception of a primary cell change command. 
         [0053]    Operation  502 : The UE obtains configuration information of a target primary cell and a target secondary cell(s) from configuration information of a primary cell and a secondary cell(s) carried in the primary cell change command in combination with the stored configuration information of all of the source primary cell and the source secondary cell(s) and changes from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0054]    Referring to  FIG. 6 , a flow chart of a method for cell handover at the base station side in this embodiment is as follows: 
         [0055]    Operation  601 : A base station generates a primary cell change command including configuration information of a primary cell. 
         [0056]    Operation  602 : The base station transmits the primary cell change command to a UE to instruct the UE to obtain configuration information of a target primary cell and a target secondary cell(s) from the configuration information of the primary cell and a secondary cell(s) carried in the primary cell change command in combination with stored configuration information of all of a source primary cell and a source secondary cell(s) and to change from the source primary cell and the source secondary cell(s) to the target primary cell and the target secondary cell(s). 
         [0057]    There are various forms of the primary cell change command and correspondingly various ways of performing cell handover including handover in a base station and handover across base stations, a process of which will be detailed below in several embodiments. 
         [0058]    Referring to  FIG. 7 , a flow chart of a cell configuration method for changing a primary cell is as follows when a primary cell change command includes a deletion instruction and an addition instruction and the deletion instruction and the addition instruction include the same cell index in this embodiment: 
         [0059]    For example, cells under a base station include a cell  1 , a cell  2 , a cell  3  and a cell  4 , and cells aggregated for a UE includes the cell  1 , the cell  2  and the cell  3  with corresponding cell indexes referring to as index  1 , index  2  and index  3 , where a primary cell is the cell  1 . The primary cell is the cell  2 , and secondary cells include the cell  1  and the cell  3  after handover. 
         [0060]    Operation  701 : The base station decides the primary cell of the UE to be changed to the cell  2  and the cell  2  among the secondary cells to be changed to the cell  1 , which is equivalent to changing-over of the primary and secondary cells. Particularly the base station may make the decision according to a measurement report from the UE. 
         [0061]    Operation  702 : The base station generates a primary cell change command including a deletion instruction and an addition instruction, and both the deletion instruction and the addition instruction include index  2 . The addition instruction in the primary cell change command further includes configuration information of the target cell corresponding to index  2 . The primary cell change command further includes index  1  and configuration information of the target primary cell corresponding to index  1 . The UE can determine from the configuration information which index corresponds to the primary cell. The configuration information of the primary cell and the secondary cell may be delta configuration information or full configuration information relative to configuration information of the source primary cell; or the configuration information of the target cell corresponding to index  1  is delta configuration information or full configuration information relative to the configuration information of the source primary cell, and the configuration information of the target cell corresponding to index  2  is delta configuration information or full configuration information relative to configuration information of the source secondary cell(s) (the cell  2  and/or the cell  3 ). 
         [0062]    Operation  703 : The base station transmits the primary cell change command to the UE. 
         [0063]    Operation  704 : The UE receives the primary cell change command and stores the configuration information of the source primary cell and the source secondary cells. 
         [0064]    Operation  705 : The UE deletes the configuration information corresponding to index  2  in response to the deletion instruction, which is equivalent to deletion of configuration information of the cell  2  (the source secondary cell). 
         [0065]    Operation  706 : The UE updates the configuration information corresponding to index  2  in response to the addition instruction, which is equivalent to addition of the configuration information of the cell  2  (the target primary cell), and also updates the configuration information of the target primary cell corresponding to index  1  and deletes the configuration information of the source primary cell (updates the configuration information). 
         [0066]    For the cell  3 , the target secondary cell and the source secondary cell are the same cell, and the UE continues the use of the stored configuration information. 
         [0067]    Operation  707 : The UE fetches system information corresponding to index  1  (the cell  2 ) and index  2  (the cell  1 ) to thereby finish changing of the cells. 
         [0068]    In this embodiment, the cell index corresponding to the primary cell is unchanged before and after changing, but the correspondence relationship between the cell and the cell index is changed. 
         [0069]    In this embodiment, the secondary cell can alternatively be changed from the cell  2  to the cell  4  simply by carrying configuration information of the cell  4  in the addition instruction. 
         [0070]    Referring to  FIG. 8 , a flow chart of a cell configuration method for changing a primary cell is as follows when a primary cell change command includes a deletion instruction and an addition instruction and the deletion instruction and the addition instruction include different cell indexes in this embodiment: 
         [0071]    For example, cells under a base station include a cell  1 , a cell  2 , a cell  3  and a cell  4 , and cells aggregated for a UE includes the cell  1 , the cell  2  and the cell  3  with corresponding cell indexes referring to as index  1 , index  2  and index  3 , where a primary cell is the cell  1 . The primary cell is the cell  2 , and secondary cells include the cell  3  and the cell  4  after changing, 
         [0072]    Operation  801 : The base station decides the primary cell of the UE to be changed to the cell  2  and the cell  2  among the secondary cells to be changed to the cell  4 . 
         [0073]    Operation  802 : The base station generates a primary cell change command including a deletion instruction and an addition instruction, and the deletion instruction includes index  2  and the addition instruction includes index  4  and configuration information corresponding to them. Particularly the addition instruction indicates that index  2  corresponds to the target primary cell and can further indicate that index  4  corresponds to the target secondary cell. Instead of the indication, for example, command combination is adopted so that index  2  is deleted and index  4  is added, which is equivalent to changing from the cell  2  corresponding to index  2 , to the cell  4  corresponding to index  4 , and since index  2  corresponds to the secondary cell before changing, index  4  also corresponds to the secondary cell after changing; or it can be known from the carried configuration information which cell is the primary cell and which cell is the secondary cell(s). The addition instruction in the primary cell change command further includes the configuration information of the target cell corresponding to index  4 . The primary cell change command further includes index  2  and the configuration information of the target primary cell corresponding to index  2 , which is equivalent to changing from the cell  1  corresponding to index  1  to the cell  2  corresponding to index  2 . 
         [0074]    Operation  803 : The base station transmits the primary cell change command to the UE. 
         [0075]    Operation  804 : The UE receives the primary cell change command and stores the configuration information of the source primary cell and the source secondary cells. 
         [0076]    Operation  805 : The UE deletes the configuration information corresponding to index  2  in response to the deletion instruction, which is equivalent to deletion of configuration information of the cell  2  (the source secondary cell). 
         [0077]    Operation  806 : The UE updates the configuration information corresponding to index  4  in response to the addition instruction, which is equivalent to addition of configuration information of the cell  4  (the target secondary cell). This operation and the operation  805  can be performed in a reversed order. 
         [0078]    The UE also updates the configuration information of the target primary cell corresponding to index  2  and deletes the configuration information of the source primary cell (updates the configuration information). 
         [0079]    For the cell  3 , the UE continues the use of the stored configuration information. 
         [0080]    Operation  807 : The UE fetches system information corresponding to index  2  (the cell  2 ) and index  4  (the cell  4 ) to thereby finish changing of the cells. 
         [0081]    In this embodiment, the cell index corresponding to the primary cell is changed before and after changing, but the correspondence relationship between the cell and the cell index is unchanged. 
         [0082]    The secondary cell can also be changed from the cell  2  to the cell  1  in the method illustrated in  FIG. 8  simply by changing index  4  to index  1  and carrying configuration information of the cell  1 . 
         [0083]    Referring to  FIG. 9 , a flow chart, of a cell configuration method for changing a primary-cell is as follows when a primary cell change command includes a change instruction and there is an unchanged correspondence relationship between a cell and a cell index in this embodiment: 
         [0084]    For example, cells under a base station include a cell  1 , a cell  2 , a cell  3  and a cell  4 , and cells aggregated for a UE includes the cell  1 , the cell  2  and the cell  3  with corresponding cell indexes referring to as index  1 , index  2  and index  3 , where a primary cell is the cell  1 . The primary cell is the cell  2 , and secondary cells include the cell  3  and the cell  4  after changing. 
         [0085]    Operation  901 : The base station decides the primary cell of the UE to be changed to the cell  2  and the cell  2  among the secondary cells to be changed to the cell  4 . 
         [0086]    Operation  902 : The base station generates a primary cell change command including a change instruction including configuration information corresponding to index  1 , index  2  and index  4 . 
         [0087]    Operation  903 : The base station transmits the primary cell change command to the UE. 
         [0088]    Operation  904 : The UE receives the primary cell change command and stores the configuration information of the source primary cell and the source secondary cells. 
         [0089]    Operation  905 : The UE deletes the configuration information corresponding to index  2  in response to the change instruction, which is equivalent to deletion of configuration information of the cell  2  (the source secondary cell). Particularly it is not necessary to perform any deletion operation with respect to index  4  because the configuration information corresponding to index  4  is not stored in the UE. 
         [0090]    Operation  906 : The UE updates the configuration information corresponding to index  4  in response to the change instruction, which is equivalent to addition of configuration information of the cell  4  (the target secondary cell). The UE also updates the configuration information of the target primary cell corresponding to index  2  and deletes the configuration information of the source primary cell (updates the configuration information). 
         [0091]    This operation and the operation  905  can be performed in a reversed order. 
         [0092]    The operation  905  and the operation  906  can also be combined, for example, the change instruction includes the configuration information corresponding to index  2  and index  4 . The UE updates local configuration information on index  4  being null with the configuration information corresponding to index  4  (the configuration information of the target secondary cell), which is equivalent to addition of the cell  4  as the secondary cell. The UE updates local configuration information on index  1  with the configuration information of the target primary cell corresponding to index  2 , which is equivalent to changing of the primary cell from the cell  1  to the cell  2 , and then the UE deletes the original configuration information of the cell  1  and the cell  2  (updates the configuration information) automatically. 
         [0093]    For the cell  3 , the UE continues the use of the stored configuration information. 
         [0094]    Operation  907 : The UE fetches system information corresponding to index  2  (the cell  2 ) and index  4  (the cell  4 ) to thereby finish changing of the cells. 
         [0095]    In this embodiment, the cell index corresponding to the primary cell is changed before and after changing, but the correspondence relationship between the cell and the cell index keeps unchanged. 
         [0096]    The secondary cell can also be changed from the cell  2  to the cell  1  in the method illustrated in  FIG. 9  simply by changing index  4  to index  1  and carrying configuration information corresponding to the cell  1 . 
         [0097]    Referring to  FIG. 10 , a flow chart of a cell configuration method for changing a primary cell is as follows when a primary cell change command includes a change instruction and there is an unchanged correspondence relationship between a primary cell and a cell index in this embodiment: 
         [0098]    For example, cells under a base station include a cell  1 , a cell  2 , a cell  3  and a cell  4 , and cells aggregated for a UE includes the cell  1 , the cell  2  and the cell  3  with corresponding cell indexes referring to as index  1 , index  2  and index  3 , where a primary cell is the cell  1 . The primary cell is the cell  2 , and secondary cells include the cell  3  and the cell  4  (index  4 ) after changing. 
         [0099]    Operation  1001 : The base station decides the primary cell of the UE to be changed to the cell  2  and the cell  2  among the secondary cells to be changed to the cell  4 , 
         [0100]    Operation  1002 : The base station generates a primary cell change command including a change instruction including configuration information corresponding to index  2  (the cell  4 ), and the primary cell change command further includes index  1  (the cell  2 ) and configuration information corresponding to index  1  (the cell  2 ). 
         [0101]    In this embodiment, the cell index corresponding to the primary cell is unchanged, but the cell index corresponding to the secondary cell can also be unchanged before and after changing. 
         [0102]    Operation  1003 : The base station transmits the primary cell change command to the UE. 
         [0103]    Operation  1004 : The UE receives the primary cell change command and stores the configuration information of the source primary cell and the source secondary cells. 
         [0104]    Operation  1005 : The UE deletes the configuration information corresponding to index  2  in response to the change instruction, which is equivalent to deletion of configuration information of the cell  2  (the source secondary cell). 
         [0105]    Operation  1006 : The UE updates the configuration information corresponding to index  2  in response to the change instruction, which is equivalent to addition of configuration information of the cell  4  (the target secondary cell). The UE updates local configuration information on index  1  with the configuration information of the target primary cell corresponding to index  1  (the cell  2 ), which is equivalent to changing of the primary cell from the cell  1  to the cell  2 , and then the UE deletes the original configuration information of the cell  1  and the cell  2  (updates the configuration information) automatically. 
         [0106]    This operation and the operation  1005  can be performed in a reversed order. 
         [0107]    The operation  1005  and the operation  1006  can also be combined, for example, the change instruction includes the configuration information corresponding to index  1  and index  2 . The UE updates stored configuration information corresponding to index  1  (the cell  1 ) with the configuration information corresponding to index  1 , which is equivalent to deletion of the cell  1  and addition of configuration of the cell  2 , thereby changing the primary cell from the cell  1  to the cell  2 . The UE updates stored configuration information corresponding to index  2  with the configuration information corresponding to index  2 , which is equivalent to deletion of the cell  2  and addition of configuration of the cell  4 , thereby changing the secondary cell from the cell  2  to the cell  4 . 
         [0108]    For the cell  3 , the UE continues the use of the stored configuration information. 
         [0109]    Operation  1007 : The UE fetches system information corresponding to index  1  (the cell  2 ) and index  2  (the cell  4 ) to thereby finish changing of the cells. 
         [0110]    In this embodiment, the cell index corresponding to the primary cell is unchanged before and after changing, but the correspondence relationship between the cell and the cell index is changed. 
         [0111]    The secondary cell can also be changed from the cell  2  to the cell  1  in the method illustrated in  FIG. 10  simply by changing the carried configuration information of the cell  4  to carried configuration information corresponding to the cell  1 . 
         [0112]    Referring to  FIG. 11 , a flow chart of a cell configuration method for changing a primary cell across base stations in this embodiment is as follows: 
         [0113]    For example, cells under a source base station include a cell  1 , a cell  2  and a cell  3 , cells under a target base station include a cell  4 , a cell  5  and a cell  6 , and cells aggregated for a UE include the cell  1 , the cell  2  and the cell  3  with corresponding cell indexes referring to as index  1 , index  2  and index  3 , where a primary cell is the cell  1 . The cells aggregated for the UE include the cell  4 , the cell  5  and the cell  6  with corresponding cell indexes referring to as index  4 , index  5  and index  6 , and the primary cell is the cell  4  after changing. 
         [0114]    Operation  1101 : The source base station decides the primary cell of the UE to be changed to the cell  4  and secondary cells to be changed to the cell  5  and the cell  6 . 
         [0115]    Operation  1102 : The source base station transmits to the target base station a change request including configuration information of the cell  1 , the cell  2  and the cell  3  (equivalent to the source primary cell and all the source secondary cells). 
         [0116]    Operation  1103 : The target base station generates a primary cell change command including configuration information corresponding to index  4 , index  5  and index  6 , that is, configuration information of the cell  4 , the cell  5  and the cell  6 . 
         [0117]    In this embodiment, the primary cell change command may alternatively still carry the cell indexes of index  1 , index  2  and index  3  as long as index  1 , index  2  and index  3  correspond to the configuration information of the cell  4 , the cell  5  and the cell  6 . 
         [0118]    The primary cell change command may include a deletion instruction and an addition instruction, for example, a deletion instruction with index  2  and an addition instruction with index  5 , a deletion instruction with index  3  and an addition instruction with index  6 , etc. Alternatively the primary cell change command includes a change instruction, for example, a change instruction with index  2  and index  3  and carrying the configuration information of the cell  4 , the cell  5  and the cell  6 . The correspondence relationship between the primary cell and the cell index is unchanged, or the correspondence relationships between the cells and the cell indexes are unchanged. Reference can be made to the flows illustrated in  FIG. 7  to  FIG. 10  for details. 
         [0119]    Operation  1104 : The target base station transmits the primary cell change command to the UE through the source base station. 
         [0120]    Operation  1105 : The UE receives the primary cell change command and stores the configuration information of the source primary cell and the source secondary cells. 
         [0121]    Operation  1106 : The UE deletes the configuration information corresponding to the cell  1 , the cell  2  and the cell  3  in response to the primary cell change command, which is equivalent to deletion of the configuration information of the source primary cell and the source secondary cells. 
         [0122]    Operation  1107 : The UE updates the configuration information corresponding to the cell  4 , the cell  5  and the cell  6  in response to the primary cell change command, which is equivalent to addition of configuration information of the target primary cell and the target secondary cells. This operation and the operation  1106  can be performed in a reversed order. 
         [0123]    If the primary cell change command includes the change instruction, then the operation  1106  and the operation  1107  can also be combined. 
         [0124]    Operation  1108 : The UE fetches system information corresponding to the cell  4 , the cell  5  and the cell  6  and establishes a connection with the target base station to thereby finish changing of the cells. 
         [0125]    In an embodiment of the invention, a UE stores configuration information of a source primary cell and source secondary cells instead of deleting the configuration information of the source primary cell and the source secondary cells immediately upon reception of a primary cell change command and then executes the primary cell change command by updating the stored configuration information of the source primary cell with configuration information of a primary cell carried in the primary cell change command and changing from the source primary cell to a target primary cell to thereby enable changing of the primary cell in an LTE-A system without performing the existing handover process. The primary cell change command in the embodiment of the invention can be a reconfiguration message or a handover command, and the carried configuration information can be delta configuration information or full configuration information. And in the embodiment of the invention, the configuration information can be updated by combining a deletion instruction and an addition instruction or by a change instruction to thereby change the cells, and such a variety of implementations can accommodate needs of different scenarios and change a primary and/or secondary cell(s) more flexibly. 
         [0126]    Those skilled in the art shall appreciate that the embodiments of the invention can be embodied as a method, a system or a computer program product. Therefore the invention can be embodied in the form of an all-hardware embodiment, an all-software embodiment or an embodiment of software and hardware in combination. Furthermore the invention can be embodied in the form of a computer program product embodied in one or more computer useable storage mediums (including but not limited to a disk memory, an optical memory, etc.) in which computer useable program codes are contained. 
         [0127]    The invention has been described in a flow chart and/or a block diagram of the method, the device (system) and the computer program product according to the embodiments of the invention. It shall be appreciated that respective flows and/or blocks in the flow chart and/or the block diagram and combinations of the flows and/or the blocks in the flow chart and/or the block diagram can be embodied in computer program instructions. These computer program instructions can be loaded onto a general-purpose computer, a specific-purpose computer, an embedded processor or a processor of another programmable data processing device to produce a machine so that the instructions executed on the computer or the processor of the other programmable data processing device create means for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0128]    These computer program instructions can also be stored into a computer readable memory capable of directing the computer or the other programmable data processing device to operate in a specific manner so that the instructions stored in the computer readable memory create an article of manufacture including instruction means which perform the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0129]    These computer program instructions can also be loaded onto the computer or the other programmable data processing device so that a series of operational steps are performed on the computer or the other programmable data processing device to create a computer implemented process so that the instructions executed on the computer or the other programmable device provide operations for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0130]    Evidently those skilled in the art can make various modifications and variations to the invention without departing from the scope of the invention. Thus the invention is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the invention and their equivalents.