Abstract:
The present invention discloses a method for triggering the sending of Sounding Reference Signals (SRS), a method for sending the SRS and an device thereof. The method for triggering the sending of SRS includes that a base station sends a downlink transmission scheduling signal to the user equipment (UE), wherein the signal carries the indication information for instructing the UE to send the SRS. By adopting the present invention, one or a plurality of UEs can be triggered by one piece of physical downlink control channel (PDCCH) signal to send the SRS.

Description:
[0001]    This application claims the priority to the Chinese Patent Application No. 201010111748.0 titled “Method for Sending Sounding Reference Signals (SRS), Trigger Method and Device Thereof” filed to the Patent Office of the People&#39;s Republic of China on Feb. 11, 2010, the entire disclosure of which is incorporated by reference herein. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates the field of wireless communication technology, in particular to the method for triggering the sending of uplink Sounding Reference Signals (SRS), and the method for sending the SRS signals and device thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    In a Long Term Evolution-Advanced (LTE-A) system, as the uplink Mult-Input Mult-Output (MIMO) supports multiple antennas transmission, for better performing the evaluation with channel quality indicator (CQI) and the uplink pre-coding selection, it is required to support the independent SRS transmission of User Equipment (UE) through the multiple antennas. 
         [0004]    In a Release-8 (REL-8) system, the SRS resources are allocated periodically, the SRS of each UE are sent periodically, and the sending parameters (such as period, sub-frame, frequency band and frequency hopping configuration) are configured by the high layer signal radio resource control (RRC) information. After receiving the commands of the base station, the UE starts sending the SRS. Before receiving the commands of closing the SRS, the UE continuously sends the SRS, therefore, the SRS configuration slowly varies. 
         [0005]    As more requirements are put forward for the SRS resources in the LET-A system, the pure semi-static configuration cannot meet the requirements. Therefore, the dynamic configuration for the SRS has been made available in this industry, namely, the configuration through a physical downlink control channel (PDCCH) (a dedicated control channel). One typical method is to add one bit during the uplink scheduling of the UE to trigger the sending of the SRS, and another is to independently send a PDCCH signal for instructing the UE to send the SRS. In the former method, the SRS configuration parameters are determined by the high-layer signaling, and the PDCCH signal is only used for triggering the sending of the SRS; in the latter method, the SRS configuration parameters are directly set in the PDCCH instructions. The two methods are to realize an independent configuration to the UE. 
         [0006]    In consideration of the realizability and efficiency of the system, and in the process of realizing the, objects of the present invention, the at least the following problems existing in the prior art were found: 
         [0007]    In one aspect, the method for triggering a single UE to send the SRS by employing PDCCH signal requires large resource consumption, especially when a plurality of UEs need to be triggered for sending SRS by employing this method, PDCCH signal needs to use a lot of resources; 
         [0008]    In a further aspect, the method for triggering a UE to send SRS by employing uplink scheduling signal leads to conflict with other UEs with respect to resource allocation when the UE sends the SRS. Even if thus conflict can be avoided, the resource allocation is to be limited to a great extent. 
       SUMMARY OF THE INVENTION 
       [0009]    The embodiments of the present invention provide a method for triggering the sending of SRS, a corresponding method for sending the SRS and a corresponding device, for solving the problem in the prior art that the existing mechanism for sending the SRS cannot instruct a plurality of UEs to send the SRS. 
         [0010]    The embodiments of the present invention provide a method and an device for triggering the sending of the SRS, for realizing the object of instructing the UE to send the SRS by employing the downlink transmission scheduling signal. 
         [0011]    The method for triggering the sending of the SRS provided in the embodiments of the present invention comprises the following steps: 
         [0012]    A base station sends the downlink transmission scheduling signal to a UE, wherein the signal carries the indication information for instructing the UE to send the SRS. 
         [0013]    The base station provided in the embodiments of the present invention comprises: 
         [0014]    A sending module for sending the downlink transmission scheduling signal to the UE, wherein the signal carries the indication information for instructing the UE to send the SRS. 
         [0015]    In the aforesaid embodiments of the present invention, the employment of the downlink transmission scheduling signal for instructing the UE to send the SRS enables the UE to send uplink SRS while performing downlink transmission, thus benefiting the support for such transmission modes as beamforming and downlink non-codebook in a better way, since these transmission modes can acquire the uplink channel information of the UE via the uplink SRS base station by making use of the reciprocity of the uplink channel and downlink channel. 
         [0016]    The method for triggering the sending of the SRS provided in the embodiments of the present invention comprises: 
         [0017]    The base station sends the PDCCH signal, which carries corresponding identifier information of a plurality of user equipments and corresponding indication information of a plurality of user equipments that are previously mentioned for indicating the sending of the SRS. The indication information is used for instructing corresponding user equipment to either send the SRS or not. 
         [0018]    The base station provided in the embodiments of the present invention comprises: 
         [0019]    A sending module for sending PDCCH signal, which carries corresponding identifier information of a plurality of user equipments and corresponding indication information of a plurality of user equipments that are previously mentioned for indicating the sending of the SRS. The indication information is used for instructing corresponding user equipment to either send the SRS or not. 
         [0020]    The method for the sending of SRS provided in the embodiments of the present invention comprises the following steps: 
         [0021]    the UE corresponding to the indication information in the PDCCH signal receives the PDCCH signal, which include the indication information for the sending of the SRS corresponding to the UE; and 
         [0022]    If the indication information instructs the UE to send the SRS, the UE sends the SRS. The UE provided in the embodiments of the present invention comprises: 
         [0023]    A receiving module for receiving the PDCCH signal when the UE is the UE corresponding to the corresponding identifier information of a plurality of UEs in the PDCCH signal, which includes the indication information for the sending of the SRS corresponding to the UE; and 
         [0024]    A sending module for sending the SRS when the receiving module receives the indication information for instructing the UE to send the SRS included in the PDCCH signal. 
         [0025]    In the above embodiments of the present invention, since the PDCCH signal sent by the base station carries the corresponding identifier information of a plurality of UEs and the corresponding indication information of the UEs, the PDCCH signal can instruct a plurality of UEs corresponding to the identifier information to send the SRS at a time. Accordingly, the UE, after receiving the PDCCH signal, can trigger the sending of the SRS according to the indication information in the PDCCH signal. It can be seen that the above embodiments realize the effect that a PDCCH signal triggers a plurality of UEs to send the SRS. Of course, products that employ the embodiments of the present do not necessarily need to have all aforesaid advantages at the same time. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    For a better understanding of the technical solution in the embodiments of the present invention or the prior art, the drawings required to use in description of the embodiments or the prior art will be introduced briefly hereinbelow. Obviously, the drawings described below are a plurality of embodiments of the present invention. 
           [0027]    Those skilled in the art can also get other drawings according to these drawings without creative work. 
           [0028]      FIG. 1  is a process diagram of the method for triggering the sending of the SRS and sending the SRS provided in the embodiments of the present invention; 
           [0029]      FIG. 2  and  FIG. 3  are schematic diagrams of the configuration parameters of the sub-frame used for transmitting the SRS in TDD system provided in the embodiments of the present invention; 
           [0030]      FIG. 4  is a schematic structure diagram of the base station apparatus provided in the embodiment I of the present invention; 
           [0031]      FIG. 5  is a schematic structure diagram of the UE provided in the embodiment I of the present invention; 
           [0032]      FIG. 6  is a process diagram of the method for triggering the sending of the SRS and sending the SRS provided in the embodiment I of the present invention; 
           [0033]      FIG. 7  is a schematic diagram of the base station apparatus provided in the embodiment I of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0034]    The technical solution in the embodiments of the present invention is explained in a clear and complete way with reference to the drawings in the embodiments of the present invention. Obviously, the embodiments described hereinbelow are only a plurality of embodiments of the present invention rather than all. All other embodiments gained by those skilled in the art on the basis of the embodiments in the present invention without any creative work shall fall within the protection scope of the present invention. 
       Embodiment I 
       [0035]    In the embodiment I, to ease the SRS resource restriction, the uplink SRS can be sent in a non-periodic way, namely, the base station sends a trigger signal to cause the UE to send the SRS. Besides, a control signal can be sent to instruct a plurality of UEs to send the SRS. 
         [0036]      FIG. 1  presents the procedure that the base station triggers the sending of the SRS provided in the embodiment I of the present invention and the procedure that the UE is triggered to send the SRS, wherein, the SRS configuration parameters can be configured to the UE via high layer signaling in advance and can comprises corresponding signal sequence, frequency band and other information. The procedure can comprise the following steps: 
         [0037]    Step  101 : the base station determines the UE that needs to send the SRS. In this step, the high layer signaling can determine which UE(s) needs to send the SRS according to the needs of the UEs or the data transmission mode and determine the identification of the UE(s). A plurality of (e.g. a group of) UEs that need to send the SRS are allowed. 
         [0038]    Step  102 : the base station sends the PDCCH signal, which carries corresponding identifier of the group of UEs. The identifier sets an indication identifier for the sending of the SRS for the group of UEs that needs to send the SRS determined in step  101  and each UE in the group of UEs. Different indication identifier values for the sending of the SRS are employed to indicate whether to require the UE to send the SRS. 
         [0039]    The indication identifier for the sending of the SRS included in the PDCCH signal can be 1 bit so as to reduce PDCCH signal overhead. If a 1 bit identifier is utilized, 0 can be set to indicate that the UE is required to send the SRS and 1 to indicate that the UE is not required to send the SRS, and vice versa. 
         [0040]    Thus, the procedure that a PDCCH signal instructs a plurality of (e.g. a group of) UEs to send the SRS is completed. 
         [0041]    In consideration that the UE receives the PDCCH signal in a blind detection way, i.e. the UE generally does not know the format of the information transmitted by the current downlink control information (DCI) and the position of the information needed by the UE. But the UE knows which information is expected, for example, currently the UE possibly expects the indication information for the sending of the SRS. The UE performs cyclic redundancy check (CRC) between radio network temporary identity (X-RNTI) and control channel element (CCE), namely the basic element of DCI. If the CRC is successful, the UE knows the information is in need and corresponding DCI format, thus DCI content. Therefore, in the embodiment I, the base station can employ SRS-RNTI as the ID number of PDCCH signal for indicate a group of UEs that the PDCCH signal is used for instructing the UE to send the SRS, thus enhancing the blind detection efficiency of the UE for PDCCH, wherein, the SRS-RNTI can correspond to a group of UEs. 
         [0042]    In consideration that the PDCCH space can be divided into common search space and specific search space for the purpose of enhancing the blind detection efficiency of the UE, in the embodiment I, the base station sends the PDCCH signal for instructing the UE to send the SRS by utilizing the common search space, so that the UE can detect the PDCCH signal in the common search space and the blind detection of the UE can be simplified. 
         [0043]    Furthermore, to reduce blind detection times, in the embodiment I, the base station builds the PDCCH for instructing the UE to send the SRS according to the length of the existing PDCCH signal. 
         [0044]    A typical PDCCH DCI format is shown as follows: 
         [0045]    Providing that the effective information bit of the DCI is 20 bit and can support 20 UEs. 20 indexes of user (user identification) respectively correspond to one of the sequence numbers from 1 to 20 and the corresponding information bit of each sequence number can be either 1 or 0, wherein, 1 represents that the UE is triggered to send the SRS, while 0 represents that the UE is not triggered to send the SRS. The UE, at the time of sending the DCI, can perform CRC for the DCI and perform XOR for the check information and SRS-RNTI to generate new check bit, the effective information bit and the check bit together forming the final information bit of the DCI, before performing channel coding and sending data via mapping. 
         [0046]    The UE triggers the sending of the SRS according to the PDCCH signal sent by the base station, which comprises: 
         [0047]    Step  103 : the UE monitors the PDCCH at a preset time and analyzes the PDCCH signal when the corresponding SRS network identifier of the user is read. 
         [0048]    In this step, according to the way that the base station sends the PDCCH signal, the UE detects whether the ID of any PDCCH signal is SRS-RNTI in the common search area during the blind detection of the PDCCH. If yes, step  104  is carried out. 
         [0049]    The embodiment I is described by taking that the UE is one of a group of UEs identified by the SRS-RNTI in the PDCCH signal as an example. 
         [0050]    Step  104 : the UE analyzes the PDCCH signal received and reads the SRS indication identifier corresponding to the UE identifier included in the PDCCH signal. 
         [0051]    Step  105 : if the UE is required to send the SRS according to the SRS indication identifier value, step  106  is followed, or step  107  is followed. 
         [0052]    Step  106 : the UE sends the SRS according to the SRS configuration parameters pre-configured to the UE. 
         [0053]    Step  107 : the UE does not send the SRS. 
         [0054]    In the above procedure, the UE can send the SRS according to the resources reserved by the system for the sending of the SRS, and to reduce conflict between resources, the base station can group the users according to the user service conditions, transmission mode and the like, allocate resources, and then inform each UE via high layer signaling. Preferably, the resources reserved by the system for a group of UEs indicated by the PDCCH signal are mutually orthogonal. 
         [0055]    In the above procedure, the UE can send the SRS according to the time sequence provided by the system. For example, after receiving the PDCCH at the nth sub-frame, the UE sends the SRS at the kth sub-frame after the nth sub-frame. The k can be determined by protocol and k should be a value that: in one aspect, ensures the time delay of the UE to receive and analyze the PDCCH and the time delay for the processing of the SRS that need to be reported to the greatest extent; in a further aspect, prevent the k from conflict with other positions for sending information as the protocol possibly appoints other positions for information. 
         [0056]    In the implementation of the embodiment I, for the UEs in frequency division duplexing (FDD), the SRS can be sent at the n+4th sub-frame, wherein, n represents the sub-frame that receives the PDCCH signal; while for the UEs in time division duplexing (TDD), the SRS can be sent at the n+kth sub-frame, wherein, n represents the sub-frame that receives the PDCCH. K value can varies according to the different time slot configuration types.  FIG. 2  and  FIG. 3  respectively show the values of k under different time slot configuration types in the TDD system. 
         [0057]    As shown in  FIG. 2 , according to the different time slot configuration (TDD UL/DL Configuration in  FIG. 2 ) types, when the sub-frame that receives the PDCCH signal is DL sub-frame number n, the number in the table is the value of the k. For example, if the TDD UL/DL (uplink/downlink) Configuration is 0 and the sub-frame that receives the PDCCH signal is sub-frame  0 , k=4; if the sub-frame that receives the PDCCH signal is sub-frame  1 , k=6; and the like. 
         [0058]    In another preferred embodiment of the present invention, the PDCCH signal further include SRS configuration parameters, thus the base station can set the parameters for the sending of the SRS for the UEs while triggering a plurality of UEs to send the SRS via a PDCCH signal, so that the UEs can send the SRS according to the parameters, thus realizing the dynamic configuration of the SRS configuration parameters. 
         [0059]    Based on the same technical concepts, the embodiment I of the present invention also provide a base station apparatus and a UE respectively. 
         [0060]    As shown in  FIG. 4 , the base station provided in the embodiment I of the present invention comprises: 
         [0061]    A sending module  401  for sending PDCCH signal, which carries corresponding identifier information of a plurality of user equipments and corresponding indication information of a plurality of user equipments that are previously mentioned for indicating the sending of the SRS. The indication information is used for instructing corresponding user equipment to either send the SRS or not. 
         [0062]    The sending module  401  can employ X-RNTI of SRS as the indication information corresponding to a plurality of UEs; and can also send the PDCCH signal in the common search space of the PDCCH. 
         [0063]    The indication information for the sending of the SRS sent by the sending module  401  is a 1 bit indication identifier. 
         [0064]    The PDCCH signal sent by the sending module  401  also includes the SRS configuration parameters, which can comprise signal sequence and frequency band information. 
         [0065]    The abovementioned base station can also comprise: 
         [0066]    A resource reservation module  402  for reserving the resources for the sending of the SRS for a plurality of UEs respectively or indicating the resources for the sending of the SRS respectively reserved for a plurality of UEs to the aforesaid UEs before the sending module  401  sends the PDCCH signal, wherein, the resources respectively reserved for a plurality of UEs can be mutually orthogonal. 
         [0067]    As shown in  FIG. 5 , the UE provided by the embodiment I of the present invention can comprises: 
         [0068]    A receiving module  501 , which is used for receiving the PDCCH signal when the UE is the one corresponding to the indication information in the PDCCH corresponding to a plurality of UEs; and the PDCCH signal contains the SRS sending indication information corresponding to the UE. When monitoring the PDCCH, the module can search the PDCCH in the public search space; 
         [0069]    A sending module  502 , which is used for sending the SRS when the SRS sending indication information in the PDCCH signal received by the receiving module  501  instructs the UE to send the SRS. Preferably, the sending module can send the SRS either according to the pre-configured SRS sending configuration information, or by using the resources reserved for the UE for sending the SRS. 
         [0070]    The sending module  502  can send the SRS through the nth sub-frame after receiving the sub-frames of the PDCCH signal, wherein, the n is a default value, as shown in  FIGS. 2 and 3 . 
         [0071]    As mentioned above, the PDCCH signal sent by the base station contains the SRS sending indication corresponding to a plurality of UEs, so as to instruct the UEs to send the SRS through one PDCCH signal. Correspondingly, after receiving the PDCCH signal, the instructed UEs trigger the sending of the SRS according to the SRS sending indication contained in the PDCCH signal. It can be seen that the embodiment I achieves the effect of triggering a plurality of UEs to send the SRS by sending a PDCCH signal. 
       Embodiment II 
       [0072]    In the embodiment II, the network side can configure the SRS configuration parameters to the UE. During the scheduling of the UE, the network side can instruct the UE to send the SRS by sending a downlink transmission scheduling signal. 
         [0073]    As shown in  FIG. 6 , the sending process of the SRS provided by the embodiment II can comprise: 
         [0074]    Step  601 : the base station schedules the downlink resources of the UE, sends the downlink transmission scheduling signal to the user equipment, and instructs the UE to send the SRS by using the signal. 
         [0075]    Step  602 : after receiving the downlink transmission scheduling signal, the UE sends the SRS according to the instructions of the signal. 
         [0076]    In the aforesaid process, the base station instructs the UE to send the SRS through a downlink transmission scheduling signal in an explicit or implicit way. 
         [0077]    If in an explicit way, the base station can carry the indication information for instructing the UE to send the SRS signal in a downlink transmission signal. Preferably, the indication information can be a 1-bit indication identifier, and the specific meanings of the identifier value can be indicated by the system, for example, if the indication identifier is 1, it means that the UE is required to send the SRS; if the indication identifier is 0, it means that the UE is not required to send the SRS. In the specific implementation, the DL grant can carry an indication identifier for instructing the UE to send the SRS. 
         [0078]    If in an implicit way, the downlink transmission scheduling signal can carry other information according to the pre-designation by the system, or that whether the UE needs to send the SRS can be instructed through the combination of other information, for example, the information bit of the localized virtual resource block/distributed virtual resource block (LVRB/DVRB) is used for instructing the triggering of SRS. If the information bit indicates the LVRB, the sending of the SRS is triggered. 
         [0079]    Preferably, to reduce the blind detection times of the downlink transmission scheduling signal by the UE, the downlink transmission scheduling signal can adopt the existing PDCCH format. 
         [0080]    Based on the same technical conceptions, the embodiment II of the present invention provides a base station apparatus. 
         [0081]    As shown in  FIG. 7 , the base station can comprise: 
         [0082]    a sending module  701 , which is used for sending the downlink transmission scheduling signal, wherein, the signal carries the indication information for instructing the UE to send the SRS. The indication information sent by the sending module  701  can be either a 1-bit indication identifier, or an information bit of the LVRB/DVRB, and if the information bit indicates the LVRB, it means the UE is instructed to send the SRS. 
         [0083]    As mentioned above, the UE is instructed to send the SRS through the downlink transmission scheduling signal, which enables the UE to send the uplink SRS when performing the downlink transmission, thus being beneficial for better supporting the beam forming, downlink non-codebook and other transmission forms. However, in the prior art, the UE is triggered to send the SRS by the uplink scheduling signal which can&#39;t be used for the downlink transmission by the UE. 
         [0084]    With the description of the preferred embodiments hereinabove, those skilled in the art can clearly understand that the present invention can be realized with the aid of software and necessary commonly used hardware platforms, or the aid of hardware of course, but the former is a preferred embodiment in most cases. Based on this understanding, the technical proposal of the present invention or the part contributing to the prior art can be reflected in the form of a software product, which is saved in a memory medium comprising instructions to enable a terminal equipment, which could be a cell phone, a personal computer, a server or a network device, to carry out the methods for each embodiment of the present invention. 
         [0085]    The above described are only the preferred embodiments of the present invention, and it is to be noted that those of ordinary skill in the art can also make a plurality of improvements without departing from the substance or scope of the present invention, wherein, the improvements are also within the protection scope of the present invention.