Abstract:
A method for indicating and determining a carrier scheduling mode in a Long Term Evolution-Advanced (LTE-A) system is disclosed in the present invention. The method is that: a network device determines whether a component carrier adopts a cross-carrier scheduling mode to perform resource scheduling, and transmits first indication information that indicating whether the component carrier adopts the cross-carrier scheduling mode to perform the resource scheduling to a User Equipment (UE), so as to indicate the UE to determine whether adopting the cross-carrier scheduling mode to perform the resource scheduling on a component carrier supported by the UE itself according to the received first indication information. By adopting the present solution, the UE supporting multi-carriers in the LTE-A system is able to determine which mode one certain component carrier or several certain component carriers adopt to perform the resource scheduling, thereby performing data reception/transmission correctly.

Description:
[0001]    The present application is a US National Stage of International Application No. PCT/CN2010/077368, filed 27 Sep. 2010, designating the United States, and claiming priority to Chinese Patent Application No. 200910235258.9, filed with the State Intellectual Property Office of China on Sep. 29, 2009 and entitled “Method, system and device for determining carrier scheduling mode”, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of radio communications and particularly to a method and device for determining a carrier scheduling mode. 
       BACKGROUND OF THE INVENTION 
       [0003]    Uplink and downlink resources are scheduled over a Physical Downlink Control Channel (PDCCH) in a Long Term Evolution (LTE) system. Particularly, a resource of a Physical Downlink Shared Channel (PDSCH) and a resource of a Physical Uplink Shared Channel (PUSCH) can be scheduled over the PDCCH. Since the LTE system is a single-carrier system, always uplink and downlink data resources of the present carrier are scheduled over the PDCCH as illustrated in  FIG. 1 . 
         [0004]    In the LTE system, there is only one carrier with the maximum bandwidth of 20 MHz available in a cell as illustrated in  FIG. 2 . In the Long Term Evolution-Advanced (LTE-A) system, the peak rate of the system is improved so greatly over the LTE system that there are a downlink rate up to 1 Gbps and an uplink rate up to 500 Mbps. Such a demand has not been satisfied over the bandwidth of 20 MHz. Carrier aggregation is introduced to the LTE-A system, that is, a plurality of consecutive or inconsecutive Component Carriers (CCs) are aggregated together in the same cell to serve concurrently a User Equipment (UE) as needed to thereby offer a desired rate. In order to ensure that the UE can operate over each aggregated component carrier in the LTE system, the maximum bandwidth of each component carrier does not exceed 20 MHz, and the largest number of component carriers aggregated in the LTE-A system is five. The CA in the LTE-A system is as illustrated in  FIG. 3 . 
         [0005]    Four CCs are aggregated in the LTE-A system illustrated in  FIG. 3 . A base station can transmit data with a UE concurrently over four component carriers to thereby improve the throughput of the system or can schedule the UE over a part of the CCs. 
         [0006]    An LTE-A system will support a larger system bandwidth, e.g., 100 MHz, than an LTE system by connecting resources of a plurality of component carriers together, particularly in the following two approaches. 
         [0007]    In a first approach, a plurality of consecutive component carriers are aggregated to provide a larger transmission bandwidth for the LTE-A. 
         [0008]    In a second approach, a plurality of inconsecutive LTE carriers are aggregated to provide a larger transmission bandwidth for the LTE-A. 
         [0009]    In view of the design complexity and the scheduling flexibility of a PDCCH as well as asymmetric uplink and downlink carrier aggregation, a PDCCH of a carrier aggregation-enabled system is designed in the following two schemes. 
         [0010]    A first scheme is the PDCCH  1   a  mode: 
         [0011]    a PDCCH is transmitted separately over each component carrier, and only a physical resource of the present carrier can be scheduled over the PDCCH, which is also referred to as intra-carrier scheduling, as illustrated in  FIG. 4 . 
         [0012]    A second scheme is the PDCCH  1   b  mode: 
         [0013]    a plurality of carrier resources are scheduled over a plurality of separate PDCCHs borne over a specific carrier, which is also referred to as cross-carrier scheduling, and this scheme is an improvement to the first scheme. In this case, a resource of only one component carrier can be scheduled over each PDCCH, as illustrated in  FIG. 5 . 
         [0014]    As for carrier scheduling, the inventors have identified the following technical problem in the prior art. 
         [0015]    In the LTE-A system, the UE cannot determine which of the modes is adopted for carrier scheduling of a component carrier supported by the UE, that is, the UE cannot determine whether to adopt the intra-carrier scheduling or the cross-carrier scheduling mode for resource scheduling of a specific CC or several CCs. 
       SUMMARY OF THE INVENTION 
       [0016]    Embodiments of the invention provide a method, system and device for determining a carrier scheduling mode in order to address such a problem that a UE cannot determine which mode is adopted for carrier scheduling of a component carrier supported by the UE in an LTE-A system. 
         [0017]    A method for indicating a carrier scheduling mode in an LTE-A system includes: 
         [0018]    determining, by a network device, whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier; and 
         [0019]    transmitting, by the network device, a first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the component carrier to a user equipment to indicate to the user equipment whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0020]    A method for determining a carrier scheduling mode in a Long Term Evolution-Advanced (LTE-A) system includes: 
         [0021]    receiving, by a user equipment, a first indicator, transmitted from a network device, of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier; and 
         [0022]    determining, by the user equipment, from the first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0023]    A network device includes: 
         [0024]    a determining unit configured to determine whether to adopt a cross-carrier scheduling mode for a component carrier of a user equipment; and 
         [0025]    a transmitting unit configured to transmit a first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the component carrier to the user equipment. 
         [0026]    A user equipment includes: 
         [0027]    a receiving unit configured to receive a first indicator, transmitted from a network device, of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier; and 
         [0028]    a determining unit configured to determine from the first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0029]    In the invention, a network device transmits an indicator of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier to a user equipment; and the user equipment determines from the received indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment, so that a UE supporting multi-carriers in an LTE-A system can determine which mode is adopted for carrier scheduling of a specific component carrier or some component carriers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a schematic diagram of intra-carrier scheduling in an LTE system in the prior art; 
           [0031]      FIG. 2  is a schematic diagram of a carrier in an LTE system in the prior art; 
           [0032]      FIG. 3  is a schematic diagram of carrier aggregation in an LTE-A system in the prior art; 
           [0033]      FIG. 4  is a schematic diagram of intra-carrier scheduling in an LTE-A system in the prior art; 
           [0034]      FIG. 5  is a schematic diagram of cross-carrier scheduling in an LTE-A system in the prior art; 
           [0035]      FIG. 6  is a schematic flow chart of a method according to an embodiment of the invention; 
           [0036]      FIG. 7  is a schematic structural diagram of a system according to an embodiment of the invention; 
           [0037]      FIG. 8  is a schematic structural diagram of a network device according to an embodiment of the invention; and 
           [0038]      FIG. 9  is a schematic structural diagram of a user equipment according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0039]    In order to enable a UE in an LTE-A system to determine which mode is adopted for carrier scheduling of a component carrier supported by the UE, an embodiment of the invention provides a method for determining a carrier scheduling mode in an LTE-A system, and in this method, a network device in the LTE-A system transmits a first indicator of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier to a user equipment to instruct the user equipment to determine from the first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0040]    Referring to  FIG. 6 , a method for determining a carrier scheduling mode in an LTE-A system according to an embodiment of the invention includes the following operations. 
         [0041]    Operation  60 : A network device transmits a first indicator of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier to a user equipment to instruct the user equipment to determine from the first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0042]    Operation  61 : The user equipment determines from the received first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0043]    In a first embodiment, the network device carries in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a component carrier and broadcasts the system message to respective user equipments subject to the network device in the operation  60 . 
         [0044]    Correspondingly, the user equipment determines from the received system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment in the operation  61 . Particularly, when the first indicator of the cross-carrier scheduling mode being adopted for resource scheduling of a component carrier is carried in the system message, the user equipment determines the cross-carrier scheduling mode to be adopted for resource scheduling over all component carriers supported by the user equipment; or when the first indicator of the cross-carrier scheduling mode being not adopted for resource scheduling of a component carrier is carried in the system message, the user equipment determines the intra-carrier scheduling mode to be adopted for resource scheduling over all component carriers supported by the user equipment. 
         [0045]    Preferably, the network device may further carry in a system message or Radio Resource Control (RRC) signalling a reconfigured second indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the component carrier and transmit the system message or the RRC signalling to the user equipment after the network device transmits the first indicator to the user equipment; and the user equipment determines again from the system message or the RRC signalling whether to adopt the cross-carrier scheduling mode or the intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment upon reception of the system message or the RRC signalling. 
         [0046]    In a second embodiment, the network device carries in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a component carrier and broadcasts the system message to the user equipment over the component carrier in the first indicator in the operation  60 . 
         [0047]    Correspondingly, the user equipment determines from the received system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier in the indicator in the operation  61 . Particularly, when the first indicator of the cross-carrier scheduling mode being adopted for resource scheduling of a component carrier is carried in the system message, the user equipment determines the cross-carrier scheduling mode to be adopted for resource scheduling over the component carrier in the first indicator; or when the first indicator of the cross-carrier scheduling mode being not adopted for resource scheduling of a component carrier is carried in the system message, the user equipment determines the intra-carrier scheduling mode to be adopted for resource scheduling over the component carrier in the first indicator. 
         [0048]    Preferably, the network device may further carry in a system message or RRC signalling a reconfigured second indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the component carrier and transmit the system message or the RRC signalling to the user equipment over the component carrier in the second indicator after the network device transmits the first indicator to the user equipment; and the user equipment determines again from the system message or the RRC signalling whether to adopt the cross-carrier scheduling mode or the intra-carrier scheduling mode for resource scheduling over the component carrier upon reception of the system message or the RRC signalling. 
         [0049]    In a third embodiment, the network device carries in RRC signalling a first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers supported by the user equipment and transmits the RRC signalling to the user equipment in the operation  60 . 
         [0050]    Correspondingly, the user equipment determines from the received RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment in the operation  61 . Particularly, when the first indicator of the cross-carrier scheduling mode being adopted for resource scheduling of all component carriers supported by the user equipment is carried in the RRC signalling, the user equipment determines the cross-carrier scheduling mode to be adopted for resource scheduling over all component carriers supported by the user equipment; or when the first indicator of the cross-carrier scheduling mode being not adopted for resource scheduling over all component carriers supported by the user equipment is carried in the RRC signalling, the user equipment determines the intra-carrier scheduling mode to be adopted for resource scheduling over all component carriers supported by the user equipment. 
         [0051]    Preferably, the network device may further carry in RRC signalling a reconfigured second indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers supported by the user equipment and transmit the RRC signalling to the user equipment after the network device transmits the first indicator to the user equipment; and the user equipment determines again from the RRC signalling whether to adopt the cross-carrier scheduling mode or the intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment upon reception of the RRC signalling. 
         [0052]    In a fourth embodiment, the network device carries in RRC signalling the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a specific component carrier supported by the user equipment and transmits the RRC signalling to the user equipment in the operation  60 . 
         [0053]    Correspondingly, the user equipment determines from the received RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier in the first indicator in the operation  61 . Particularly, when the first indicator of the cross-carrier scheduling mode being adopted for resource scheduling of the specific component carrier supported by the user equipment is carried in the RRC signalling, the user equipment determines the cross-carrier scheduling mode to be adopted for resource scheduling over the component carrier in the first indicator; or when the first indicator of the cross-carrier scheduling mode being not adopted for resource scheduling of the specific component carrier supported by the user equipment is carried in the RRC signalling, the user equipment determines the intra-carrier scheduling mode to be adopted for resource scheduling over the component carrier in the first indicator. 
         [0054]    Preferably, the network device may further carry in RRC signalling a reconfigured second indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the specific component carrier supported by the user equipment and transmit the RRC signalling to the user equipment after the network device transmits the first indicator to the user equipment; and the user equipment determines again from the RRC signalling whether to adopt the cross-carrier scheduling mode or the intra-carrier scheduling mode for resource scheduling over the component carrier in the second indicator upon reception of the RRC signalling. 
         [0055]    After the operation  61 , the user equipment detects a Physical Downlink Control Channel (PDCCH) over the component carrier, for which the cross-carrier scheduling mode is determined to be adopted for resource scheduling, in accordance with a Downlink Control Information (DCI) format corresponding to the cross-carrier scheduling mode; or the user equipment detects a PDCCH over the component carrier, for which the cross-carrier scheduling mode is determined not to be adopted for resource scheduling, in accordance with a DCI format corresponding to the intra-carrier scheduling mode. The DCI format corresponding to the cross-carrier scheduling mode includes at least information on the number of the carrier where the scheduled physical resource is located, so that the UE can acquire a resource scheduling instruction of the corresponding carrier from the number of the carrier included in the DCI by monitoring the carrier where the PDCCH is located and further transmit and receive data over the scheduled carrier resource. The DCI format corresponding to the intra-carrier scheduling mode does not include information on the number of any carrier. 
         [0056]    Preferably, the network device may further transmit identifiers of all or a part of component carriers supported by the LTE-A system to the user equipment when the network device transmits the first indicator or the second indicator to the user equipment in the operation  60 ; and the user equipment may determine a frequency point location of a component carrier from the received identifier of the component carrier. 
         [0057]    The invention will be detailed below. 
         [0058]    The method in the present invention may be performed in the following several solutions. 
       The First Solution: 
       [0059]    A user equipment is notified of whether the system adopts cross-carrier scheduling, i.e., whether to adopt the PDCCH  1   b  mode, from the network side by broadcasting a system message. 
         [0060]    This solution is applicable to cross-carrier scheduling configuration in which one CC is not distinguished from another at the system level, that is, each UE is configured at the network side to have the cross-carrier scheduling mode enabled or not enabled, that is, the same configuration value is broadcasted over each CC participating in broadcasting the system message. Information on the carrier number of each CC that can be aggregated in the system may further be broadcasted from the network side. If cross-carrier scheduling is configured to be enabled in the system message broadcast, the configuration is validated if a UE receiving the broadcast is capable of supporting cross-carrier scheduling, i.e., the UE performs cross-carrier scheduling in the PDCCH  1   b  mode by using the carrier number; or the UE performs resource scheduling only in the intra-carrier scheduling (i.e., PDCCH  1   a ) mode if the UE is incapable of supporting cross-carrier scheduling. If cross-carrier scheduling is configured not to be enabled in the system message broadcast, each UE receiving the broadcast enables only the intra-carrier scheduling mode and disables the PDCCH  1   b  mode. 
         [0061]    If a configuration scheme regarding cross-carrier scheduling is changed in the system, this will be reflected in a change to the system message, and the UE can acquire information on the changed carrier scheduling configuration by monitoring the changed system message; and a connected UE can further be notified of the change to the carrier scheduling configuration scheme from the network side in dedicated RRC signalling. 
       The Second Solution: 
       [0062]    A user equipment is notified of whether to enable cross-carrier scheduling for each component carrier in the system from the network side by broadcasting a system message. 
         [0063]    This solution is applicable to cross-carrier scheduling configuration in which one CC is distinguished from another at the system level, that is, each UE is configured at the network side to have the cross-carrier scheduling mode enabled or not enabled for each CC that can be aggregated, i.e., a configuration value of the carrier scheduling mode over each CC participating in broadcasting the system message is broadcasted over the corresponding CC. Information on the carrier number of each CC participating in broadcasting the system message or the carrier numbers of all the other CCs that can be aggregated may further be broadcasted over the corresponding CC. If cross-carrier scheduling is configured to be enabled in the system message broadcast over a specific CC, the configuration over that carrier is validated (that is, cross-carrier scheduling is performed in the PDCCH  1   b  mode by using the carrier number) if a UE receiving the broadcast is capable of supporting cross-carrier scheduling; or the UE enables only the intra-carrier scheduling (i.e., PDCCH  1   a ) mode over that carrier if the UE is incapable of supporting cross-carrier scheduling. If cross-carrier scheduling is configured not to be enabled in the system message broadcast over a specific CC, each UE receiving the broadcast enables only the intra-carrier scheduling mode and disables the PDCCH  1   b  mode. 
         [0064]    If a configuration scheme regarding cross-carrier scheduling over a specific CC is changed in the system, this will be reflected in a change to the system message over that CC, and the UE can acquire information on the changed carrier scheduling configuration by monitoring the changed system message over that CC; and a connected UE may further be notified of the change to the carrier scheduling configuration scheme of a specific CC or some CCs in dedicated RRC signalling. 
       The Third Solution: 
       [0065]    A UE is notified of whether to enable cross-carrier scheduling from the network side in dedicated RRC signalling. 
         [0066]    This solution is applicable to cross-carrier scheduling configuration in which one CC is not distinguished from another at the UE level, that is, each UE can be configured with a different carrier scheduling scheme at the network side but without distinguishing one CC from another while configuring a specific UE with a carrier scheduling scheme, that is, the UE is configured to have the PDCCH  1   b  mode enabled separately, and a different carrier scheduling scheme can be enabled for a different UE in the same system. 1-bit information can be used at the network side in RRC signalling, in which a carrier scheduling scheme of a UE is configured, to indicate whether the PDCCH  1   b  mode is enabled for the UE, and also information on the numbers of all the current aggregated carriers or all the carriers that can be aggregated of the UE can optionally be carried in the signalling for use in the cross-carrier scheduling mode. 
         [0067]    A carrier scheduling scheme configured for a specific UE can be reconfigured separately at the network side in dedicated RRC signalling. 
       The Fourth Solution: 
       [0068]    A UE is notified of whether to enable cross-carrier scheduling for a specific component carrier from the network side in dedicated RRC signalling. 
         [0069]    This solution is applicable to cross-carrier scheduling configuration in which one CC is distinguished from another at the UE level, that is, each carrier that can be aggregated of each UE can be configured with a different carrier scheduling scheme at the network side. 1-bit information can be used at the network side in RRC signalling, in which a carrier scheduling scheme over a specific carrier of a UE is configured, to indicate whether the PDCCH  1   b  mode is enabled over that CC, and also information on the number corresponding to that CC or the numbers of all the current aggregated carriers of the UE can optionally be carried in the signalling for use in the cross-carrier scheduling mode. 
         [0070]    A carrier scheduling scheme configured for a specific CC in a set of CCs that can be aggregated for a specific UE can be reconfigured separately at the network side in dedicated RRC signalling. 
         [0071]    The method in the invention will be described below in embodiments. 
       The First Embodiment 
       [0072]    This embodiment corresponds to the foregoing first solution and is particularly as follows. 
         [0073]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, each of which is a backward compatible carrier. The cross-carrier scheduling mode being configured in the system to be enabled is broadcasted over each of the CC 1 , the CC 2  and the CC 3  together with information on the carrier numbers of all the CCs, {{CC 1 ,  00 }, {CC 2 ,  01 }, {CC 3 ,  10 }}. A UE 1  capable of supporting cross-carrier scheduling enables the PDCCH  1   b  mode to use the CC 1  in scheduling data transmission over the CC 1 , the CC 2  and the CC 3 , a UE 2  capable of supporting cross-carrier scheduling enables the PDCCH  1   b  mode to use the CC 2  in scheduling data transmission over the CC 2  and the CC 3 , and a UE 3  incapable of supporting cross-carrier scheduling disables the PDCCH  1   b  mode and enables the intra-carrier scheduling mode. 
       The Second Embodiment 
       [0074]    This embodiment corresponds to the foregoing second solution and is particularly as follows. 
         [0075]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, where the CC 1  and the CC 2  are backward compatible carriers and the CC 3  is an extended carrier. The cross-carrier scheduling mode is configured in a system message over the CC 1  not to be enabled for that carrier; the cross-carrier scheduling mode is configured in a system message broadcasted over the CC 2  to be enabled for that carrier, and information on the carrier numbers of the CC 2  and the CC 3 , {{CC 2 ,  01 }, {CC 3 ,  10 }} is broadcasted; and no system message broadcast is set over the CC 3 . Each UE capable of supporting cross-carrier scheduling in the system disables the PDCCH  1   b  mode over the CC 1  and enables intra-carrier scheduling for data transmission over the CC 1  as well as enables the PDCCH  1   b  mode over the CC 2  for cross-carrier scheduling for data transmission over the CC 2  and the CC 3 . Other UEs incapable of supporting cross-carrier scheduling enables the intra-carrier scheduling mode. 
       The Third Embodiment 
       [0076]    This embodiment corresponds to the foregoing third solution and is particularly as follows. 
         [0077]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, where the CC 1  and the CC 2  are backward compatible carriers and the CC 3  is an extended carrier. A UE 1  operates with aggregation over the CC 1  and the CC 2 , and a UE 2  operates with aggregation over all the three CCs. Cross-carrier scheduling is configured in RRC signalling from the network side to the UE 1  not to be enabled and is configured in RRC signalling to the UE 2  to be enabled. Upon reception of the respective RRC configuration signalling, the UE 1  disables the PDCCH  1   b  mode over both the CC 1  and the CC 2  and enables the intra-carrier scheduling mode to schedule data transmission over the respective carriers, and the UE 2  disables the PDCCH  1   a  mode over the CC 1  and enables cross-carrier scheduling for data transmission over the CC 1 , the CC 2  and the CC 3 . 
       The Fourth Embodiment 
       [0078]    This embodiment corresponds to the foregoing fourth solution and is particularly as follows. 
         [0079]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, where the CC 1  and the CC 2  are backward compatible carriers and the CC 3  is an extended carrier. A UE 1  operates with aggregation over the CC 1  and the CC 2 , and a UE 2  operates with aggregation over all the three CCs. Cross-carrier scheduling is configured in RRC signalling from the network side to the UE 1  to be enabled for both the CC 1  and the CC 2  and is configured in RRC signalling to the UE 2  to be enabled for the CC 1  and the CC 3  but not for the CC 2 . Upon reception of the respective RRC configuration signalling, the UE 1  enables cross-carrier scheduling over the CC 1  for data transmission over the CC 1  and the CC 2 ; and the UE 2  enables cross-carrier scheduling over the CC 1  for data transmission over the CC 1  and the CC 3  and enables the intra-carrier scheduling mode over the CC 2 . 
       The Fifth Embodiment 
       [0080]    A carrier scheduling mode is reconfigured in RRC signalling in this embodiment particularly as follows. 
         [0081]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, where the CC 1  and the CC 2  are backward compatible carriers and the CC 3  is an extended carrier. A UE 1  operates with aggregation over all the three CCs and complies with currently received RRC configuration signalling by enabling cross-carrier scheduling over the CC 1  for data transmission over the CC 1  and the CC 3  and enabling the intra-carrier scheduling mode over the CC 2 . Thereafter RRC reconfiguration signalling is transmitted from the network side to the UE 1  to indicate cross-carrier scheduling being not enabled for the CC 1  but enabled for the CC 2  and the CC 3 . The UE 1  enables cross-carrier scheduling over the CC 2  for data transmission over the CC 2  and the CC 3  and enables the intra-carrier scheduling mode over the CC 1  upon reception of the reconfiguration signalling. 
       The Sixth Embodiment 
       [0082]    A carrier scheduling mode is reconfigured by broadcasting a system message in this embodiment particularly as follows. 
         [0083]    There are three component carriers in an LTE-A system, denoted with CC 1 , CC 2  and CC 3  respectively, where the CC 1  and the CC 2  are backward compatible carriers and the CC 3  is an extended carrier. At this time, cross-carrier scheduling is configured in a system message over the CC 1  not to be enabled; the cross-carrier scheduling mode is configured in a system message broadcasted over the CC 2  to be enabled, and information on the carrier numbers of the CC 2  and the CC 3 , {{CC 2 ,  01 }, {CC 3 ,  10 }} is broadcasted; and no system message broadcast is set over the CC 3 . A connected UE 1  receiving the broadcast operates over the three component carriers with intra-carrier scheduling being enabled over the CC 1  and data transmission over the CC 2  and the CC 3  being scheduled over the CC 2 . Then there is such a change to the carrier scheduling scheme of the system that the cross-carrier scheduling mode is configured to be enabled for each CC. Thus, cross-carrier scheduling is configured in both of the system messages over the CC 1  and the CC 2  to be enabled, and the carrier number of the CC 1 , {CC 1 ,  00 } is broadcasted over the CC 1 . The UE 1  acquires the changed carrier scheduling scheme of the system by monitoring the change to the system messages over the CC 1  and the CC 2  and enables the CC 1  in scheduling data transmission over the CC 1 , the CC 2  and the CC 3 . 
         [0084]    Referring to  FIG. 7 , an embodiment of the invention further provides a system for scheduling a carrier resource, and this system includes: 
         [0085]    a network device  70  configured to transmit a first indicator of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier to a user equipment; and 
         [0086]    the user equipment  71  configured to determine from the received first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0087]    In a first embodiment, the network device  70  is configured to carry in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers in the system and broadcast the system message to the user equipment. 
         [0088]    Correspondingly, the user equipment  71  is configured to determine from the broadcasted system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment. 
         [0089]    In a second embodiment, the network device  70  is configured to carry in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a specific component carrier and broadcast the system message to the user equipment over the component carrier. 
         [0090]    Correspondingly, the user equipment  71  is configured to determine from the broadcasted system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier. 
         [0091]    In a third embodiment, the network device  70  is configured to carry in Radio Resource Control (RRC) signalling the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers supported by the user equipment and transmit the RRC signalling to the user equipment. 
         [0092]    Correspondingly, the user equipment  71  is configured to determine from the RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment. 
         [0093]    In a fourth embodiment, the network device  70  is configured to carry in Radio Resource Control (RRC) signalling the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a specific component carrier supported by the user equipment and transmit the RRC signalling to the user equipment. 
         [0094]    Correspondingly, the user equipment  71  is configured to determine from the RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier. 
         [0095]    The user equipment  71  is further configured to detect a PDCCH over the component carrier, for which the cross-carrier scheduling mode is determined to be adopted for resource scheduling, in accordance with a DCI format corresponding to the cross-carrier scheduling mode; or to detect a PDCCH over the component carrier, for which the cross-carrier scheduling mode is determined not to be adopted for resource scheduling, in accordance with a DCI format corresponding to the intra-carrier scheduling mode. 
         [0096]    The network device  70  is further configured to transmit identifiers of all or a part of component carriers supported by the LTE-A system to the user equipment. 
         [0097]    Correspondingly, the user equipment  71  is further configured to determine a frequency point location of a component carrier from the received identifier of the component carrier. 
         [0098]    Referring to  FIG. 8 , an embodiment of the invention further provides a network device applicable to a system for scheduling a carrier resource, and this network device includes: 
         [0099]    a determining unit  80  configured to determine whether to adopt a cross-carrier scheduling mode for a component carrier; and 
         [0100]    a transmitting unit  81  configured to transmit a first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of the component carrier to a user equipment. 
         [0101]    The transmitting unit  81  includes one or any combination of a first indicating unit, a second indicating unit, a third indicating unit and a fourth indicating unit. 
         [0102]    The first indicating unit is configured to carry in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers and broadcast the system message to the user equipment. 
         [0103]    The second indicating unit is configured to carry in a system message the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a specific component carrier and broadcast the system message to the user equipment over the component carrier. 
         [0104]    The third indicating unit is configured to carry in Radio Resource Control (RRC) signalling the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of all component carriers supported by the user equipment and transmit the RRC signalling to the user equipment. 
         [0105]    The fourth indicating unit is configured to carry in Radio Resource Control (RRC) signalling the first indicator of whether to adopt the cross-carrier scheduling mode for resource scheduling of a specific component carrier supported by the user equipment and transmit the RRC signalling to the user equipment. 
         [0106]    The transmitting unit  81  is further configured to transmit identifiers of all or a part of component carriers supported by the LTE-A system to the user equipment. 
         [0107]    Referring to  FIG. 9 , an embodiment of the invention provides a user equipment including: 
         [0108]    a receiving unit  90  configured to receive a first indicator, transmitted from a network device, of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier; and 
         [0109]    a determining unit  91  configured to determine from the first indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment. 
         [0110]    In a first embodiment, the receiving unit  90  is configured to receive a system message, broadcasted from the network device, carrying the first indicator. 
         [0111]    Correspondingly, the determining unit  91  is configured to determine from the system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment. 
         [0112]    In a second embodiment, the receiving unit  90  is configured to receive a system message carrying the first indicator over the component carrier. 
         [0113]    Correspondingly, the determining unit  91  is configured to determine from the system message whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier in the first indicator. 
         [0114]    In a third embodiment, the receiving unit  90  is configured to receive Radio Resource Control (RRC) signalling, transmitted from the network device, carrying the first indicator. 
         [0115]    Correspondingly, the determining unit  91  is configured to determine from the RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over all component carriers supported by the user equipment. 
         [0116]    In a fourth embodiment, the receiving unit  90  is configured to receive Radio Resource Control (RRC) signalling, transmitted from the network device, carrying the first indicator. 
         [0117]    Correspondingly, the determining unit  91  is configured to determine from the RRC signalling whether to adopt the cross-carrier scheduling mode or an intra-carrier scheduling mode for resource scheduling over the component carrier in the first indicator. 
         [0118]    The user equipment further includes: 
         [0119]    a detecting unit  92  configured to detect a PDCCH over the component carrier, for which the determining unit determines the cross-carrier scheduling mode to be adopted for resource scheduling, in accordance with a DCI format corresponding to the cross-carrier scheduling mode; or to detect a PDCCH over the component carrier, for which the determining unit determines the cross-carrier scheduling mode not to be adopted for resource scheduling, in accordance with a DCI format corresponding to the intra-carrier scheduling mode. 
         [0120]    The network device in the invention can be a base station or any other device at the network side capable of communication with the user equipment. 
         [0121]    In summary the invention offers the following advantageous effects. 
         [0122]    In the embodiments of the invention, a network device transmits an indicator of whether to adopt a cross-carrier scheduling mode for resource scheduling of a component carrier to a user equipment; and the user equipment determines from the received indicator whether to adopt the cross-carrier scheduling mode for resource scheduling over the component carrier supported by the user equipment, so that a UE supporting multi-carriers in an LTE-A system can determine which mode is adopted for carrier scheduling of a specific component carrier or some component carriers and further receive corresponding scheduling signalling according to the scheduling mode to thereby transmit and receive data over a scheduled data resource. 
         [0123]    Those skilled in the art shall appreciate that the embodiments of the invention can be embodied as a method, system or 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, a CD-ROM, an optical memory) in which computer useable program codes are contained. 
         [0124]    The invention has been described in a flow chart and/or a block diagram of the method, device (system) and 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 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. 
         [0125]    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. 
         [0126]    These computer program instructions can also be loaded onto the computer or the other programmable data processing device so that a series of operations 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. 
         [0127]    Although the preferred embodiments of the invention have been described, those skilled in the art benefiting from the underlying inventive concept can make additional modifications and variations to these embodiments. Therefore, the appended claims are intended to be construed as encompassing the preferred embodiments and all the modifications and variations coming into the scope of the invention. 
         [0128]    It will be appreciated that one skilled in the art may make various modifications and alterations to the present invention without departing from the scope of the present invention. Accordingly, if these modifications and alterations to the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention intends to include all these modifications and alterations.