Base station apparatus, radio communication system, and radio communication controlling method

A processor performs a process that includes decoding, from among a radio signal received by the radio signal receiving apparatus, control data that includes information indicating frequency bands that a mobile station apparatus is capable of dealing with, component carriers and scenarios for carrier aggregation, receiving the decoded control data, calculating, in accordance with the received control data, a transmission-bandwidth adjacency level value indicating a policy on component-carrier allocation to the mobile station apparatus, determining, in accordance with the calculated transmission-bandwidth adjacency level value, a component carrier to be allocated to the mobile station apparatus from among the component carriers and the frequency bands that the mobile station apparatus is capable of dealing with; and generating a transmission signal that includes information indicating the determined component carrier.

FIELD

The embodiments discussed herein are related to a base station apparatus, a radio communication system, and a radio communication controlling method.

BACKGROUND

In the field of radio communication technology, communication techniques have been studied and developed for enabling higher-speed and higher-capacity data communications between mobile station apparatuses and base station apparatuses.

In the Third Generation Partnership Project (3GPP), which is a standard-setting organization for a mobile radio communication scheme, the Long Term Evolution (LTE), i.e., a 3.9-generation radio communication scheme is standardized. Some carriers have already started providing LTE-based radio communication services. The 3GPP is also thinking of standardizing LTE-Advanced (LTE-A) as a succeeding radio communication scheme compatible with LTE. Note that LTE is also called the Evolved Universal Terrestrial Radio Access (E-UTRA) and that LTE-A is also called the Advanced E-UTRA.

To enable higher-speed and higher-capacity data communications, LTE-A is scheduled to allow communications based on greater frequency bandwidths than those in LTE, i.e., a scheme in which communications are performed using carriers with a maximum frequency bandwidth of 20 MHz.

Specifically, LTE-A defines carrier signals with a frequency bandwidth used in LTE as Component Carriers (CC), thereby enabling communications with a greater frequency bandwidth to be performed using a plurality of component carriers simultaneously. Such a technology, i.e., a technology that enables broadband transmission using a plurality of component carriers simultaneously, is called Carrier Aggregation (CA).

In a prior art, a base station apparatus allocates appropriate wireless resources to a mobile station apparatus according to mobile station component carrier information received from the mobile station apparatus, including wireless parameters.

In another prior art, in an LTE-A system which performs carrier aggregation, in the continuous allocating of bandwidths to mobile stations, a base station reports, to the mobile stations, VRB (Nstart) of information on a bandwidth that starts to be used and the number Nlengthof PRBs in use.

SUMMARY

According to an aspect of the embodiments, a base station apparatus includes a radio signal receiving apparatus that receives a radio signal transmitted from a mobile station apparatus, a radio signal transmitting apparatus, and a processor. The processor performs a process that includes decoding, from among the radio signal received by the radio signal receiving apparatus, control data that includes information indicating frequency bands that the mobile station apparatus is capable of dealing with, component carriers and scenarios for carrier aggregation, receiving the decoded control data, calculating, in accordance with the received control data, a transmission-bandwidth adjacency level value indicating a policy on component-carrier allocation to the mobile station apparatus, determining, in accordance with the calculated transmission-bandwidth adjacency level value, a component carrier to be allocated to the mobile station apparatus from among the component carriers and the frequency bands that the mobile station apparatus is capable of dealing with, and generating a transmission signal that includes information indicating the determined component carrier. The radio signal transmitting apparatus transmits the generated transmission signal to the mobile station apparatus.

DESCRIPTION OF EMBODIMENTS

The following will describe embodiments in detail with reference to the drawings. It should be noted that the described embodiments are not to be considered to be exclusive but may be combined with each other. Processes and processing flows of the individual embodiments are illustrative. It should also be noted that, if necessary, such processes can be replaced with similar processes, further processes may be added thereto, and an order in which such processes are performed may be changed.

First Embodiment

As described above, use of LTE-A, which achieves broadband transmission based on carrier aggregation, as a succeeding radio communication scheme compatible with LTE has been thought of. Putting LTE-A into practical use leads to simultaneous presence of both mobile station apparatuses adapted to LTE and mobile station apparatuses adapted to LTE-A and may lead to a transient presence of a radio communication system in which these mobile station apparatuses communicate with the same base station apparatus.

Accordingly, in such a transient radio communication system, the base station apparatus needs to control allocation of radio resources in accordance with the communication capabilities of connection-target mobile station apparatuses, e.g., in accordance with whether the mobile station apparatuses are capable of performing carrier aggregation.

Even when a connection-target mobile station apparatus is capable of performing carrier aggregation, the base station apparatus needs to control allocation of radio resources in consideration of the scenario for the carrier aggregation the mobile station apparatus is capable of dealing with.FIG. 1is an explanatory diagram of scenarios for carrier aggregation. As depicted inFIG. 1, the scenarios for carrier aggregation include, for example, (a) allocation of continuous component carriers within the same frequency band, (b) allocation of component carriers of different frequency bands, and (c) allocation of discontinuous component carriers within the same frequency band.

In some cases, all component carriers that a connection-target mobile station apparatus is capable of dealing with have already been allocated to other mobile station apparatuses. In such cases, a mobile station apparatus needs to control allocation of radio resources so as to secure component carriers to be allocated to the connection-target mobile station apparatus.

In view of at least one of the necessities described above, in a radio communication system in accordance with a first embodiment, a base station apparatus performs control for allocating radio resources in accordance with the communication capabilities of individual connection-target mobile station apparatuses, e.g., in accordance with whether a connection-target mobile station apparatus is capable of performing carrier aggregation, and in accordance with what scenario for carrier aggregation the mobile station apparatus is capable of dealing with.

FIG. 2is a configuration diagram of a radio communication system in accordance with an embodiment.

A radio communication system1depicted inFIG. 2includes a base station apparatus100, a first mobile station apparatus200A, and a second mobile station apparatus200B. AlthoughFIG. 2depicts two mobile station apparatuses, the radio communication system1in accordance with the embodiment may include any number of mobile station apparatuses. Both the first mobile station apparatus200A and the second mobile station apparatus200B will hereinafter be referred to as mobile station apparatuses200when the first mobile station apparatus200A and the second mobile station apparatus200B are not distinguished from each other.

Upon receipt of a connection request from a mobile station apparatus200within a communication area, the base station apparatus100allocates an appropriate component carrier in accordance with the communication capability of the mobile station apparatus200and communicates with the mobile station apparatus200.

The first mobile station apparatus200A and the second mobile station apparatus200B communicate with the base station apparatus100in accordance with different communication schemes compatible with each other. The first mobile station apparatus200A is, for example, a mobile station apparatus adapted to LTE-A and capable of performing a broadband communication with the base station apparatus100using a plurality of component carriers through carrier aggregation. The second mobile station apparatus200B is, for example, a mobile station apparatus adapted to LTE, and communicates with the base station apparatus100using one component carrier. Each of the mobile station apparatuses200has, as portions of mobile station capability information (UE capability information), information on the availability of carrier aggregation and information on a scenario for carrier aggregation that is capable of being dealt with.

FIG. 3is a schematic configuration diagram of abase station apparatus in accordance with the first embodiment.

As depicted inFIG. 3, the base station apparatus100includes a processing apparatus110, a transmission signal multiplexer120, a radio signal transmitting apparatus130, a radio signal receiving apparatus140, a received signal separator-demodulator150, a storage device160, an antenna170, and a communication interface180. The processing apparatus110includes a radio-resource allocation controlling unit111, a user data decoding unit112, a control data processing unit113, and a downlink signal generating unit114. The storage device160includes a radio resource management file161, a transmission-bandwidth adjacency level value management file162, and a mobile station capability information management file163.

The radio signal receiving apparatus140receives an uplink signal transmitted from the mobile station apparatus200via the antenna170. An uplink signal is a radio signal transmitted from the mobile station apparatus200to the base station apparatus100.

The received signal separator-demodulator150separates the uplink signal received by the radio signal receiving apparatus140in accordance with a component carrier used for the transmission by the mobile station apparatus200, and demodulates the uplink signal for each separated component carrier.

The user data decoding unit112decodes user data included in the uplink signal separated and demodulated by the received signal separator-demodulator150.

The control data processing unit113decodes and transmits control data included in the uplink signal separated and demodulated by the received signal separator-demodulator150to the radio-resource allocation controlling unit111.

The control data decoded by the control data processing unit113includes data on mobile station capability information of the mobile station apparatus200. The data on mobile station capability information of the mobile station apparatus200is recorded in the mobile station capability information management file163within the storage device160.

Mobile station capability information included in control data includes information on a frequency band and component carrier capable of being allocated to the mobile station apparatus200.

Mobile station capability information includes, for both an uplink signal and a downlink signal, information on a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with. A downlink signal is a radio signal transmitted from the base station apparatus100to the mobile station apparatus200. Information on the scenario for carrier aggregation is information on allocation of continuous component carriers within the same frequency band and allocation of component carriers of different frequency bands, and information indicating whether individual discontinuous component carriers within the same frequency band are capable of being allocated.

Control data decoded by the control data processing unit113may include data on a radio communication quality for each component carrier measured for a downlink signal by the mobile station apparatus200.

The control data processing unit113estimates, from an uplink signal received from the mobile station apparatus200, the radio communication quality of the uplink signal for each component carrier. The control data processing unit113transmits data on the estimated radio communication quality of the uplink signal to the radio-resource allocation controlling unit111.

For every connection-target mobile station apparatus200within a communication area of the base station apparatus100, the radio-resource allocation controlling unit111performs control for allocating radio resources in consideration of, for example, the communication capability of the mobile station apparatus200, the radio communication quality for each component carrier, and the channel fluctuation situation. That is, the radio-resource allocation controlling unit111dynamically allocates a downlink channel from the base station apparatus100to each mobile station apparatus200and an uplink channel from each mobile station apparatus200to the base station apparatus100.

In the first embodiment, the radio-resource allocation controlling unit111calculates a transmission-bandwidth adjacency level value for each mobile station apparatus200according to mobile station capability information received from the control data processing unit113. The calculated transmission-bandwidth adjacency level value indicates whether the mobile station apparatus200is capable of dealing with carrier aggregation, and indicates a carrier aggregation whose scenario is capable of being dealt with by the mobile station apparatus200. That is, a transmission-bandwidth adjacency level value indicates policies on component-carrier allocation to the mobile station apparatus200.

In particular, the radio-resource allocation controlling unit111calculates a transmission-bandwidth adjacency level value for an uplink signal using mobile station capability information related to the scenario of a carrier aggregation capable of being dealt with for the uplink signal. The radio-resource allocation controlling unit111also calculates a transmission-bandwidth adjacency level value for a downlink signal using mobile station capability information related to the scenario of a carrier aggregation capable of being dealt with for the downlink signal.

The radio-resource allocation controlling unit111stores the transmission-bandwidth adjacency level value calculated for each mobile station apparatus200in the transmission-bandwidth adjacency level value management file162within the storage device160.

The radio-resource allocation controlling unit111reads the radio resource management file161stored in the storage device160. The radio resource management file161includes data on frequency bands and component carriers that the base station apparatus100is capable of allocating, and data on the allocation situation of component carriers to mobile station apparatuses200.

In accordance with a transmission-bandwidth adjacency level value, the radio-resource allocation controlling unit111extracts component carriers of a downlink signal as candidates for allocation to a mobile station apparatus200from the component carriers within the radio resource management file161. In accordance with, for example, the channel fluctuation situation and the radio communication quality of a downlink signal for each component carrier, the radio-resource allocation controlling unit111determines a component carrier of the downlink signal to be allocated to the mobile station apparatus200from among the component carriers extracted as candidates for allocation. The radio-resource allocation controlling unit111reflects a result of a determination on allocation of the component carrier in the radio resource management file161.

In accordance with the transmission-bandwidth adjacency level value, the radio-resource allocation controlling unit111also extracts component carriers of an uplink signal as candidates for allocation to the mobile station apparatus200from the component carriers within the radio resource management file161. In accordance with, for example, the channel fluctuation situation and the radio communication quality of an uplink signal for each component carrier, the radio-resource allocation controlling unit111determines a component carrier of the uplink signal to be allocated to the mobile station apparatus200from among the component carriers extracted as candidates for allocation. The radio-resource allocation controlling unit111reflects a result of a determination on allocation of the component carrier in the radio resource management file161.

The downlink signal generating unit114generates a downlink signal to be transmitted from the base station apparatus100to the mobile station apparatus200. The generated downlink signal may include a control signal that includes data indicating the component carrier that the radio-resource allocation controlling unit111has determined to allocate.

The transmission signal multiplexer120multiplexes the downlink signal generated by the downlink signal generating unit114with the component carrier of the downlink signal determined by the radio-resource allocation controlling unit111.

The radio signal transmitting apparatus130transmits the downlink signal multiplexed by the transmission signal multiplexer120to the mobile station apparatus200via the antenna170.

The processing apparatus110transmits, via the communication interface180, control data and user data to and receives control data and user data from host apparatuses (not illustrated) for the base station apparatus100, e.g., Mobility Management Entity (MME) and Serving Gateway (S-GW).

FIG. 4is an exemplary hardware configuration diagram of a base station apparatus in accordance with the first embodiment.

The processing apparatus110depicted inFIG. 3corresponds to, for example, a Central Processing Unit (CPU)310of abase station apparatus300depicted inFIG. 4. The transmission signal multiplexer120, the radio signal transmitting apparatus130, the radio signal receiving apparatus140, and the received signal separator-demodulator150correspond to, for example, a Digital Signal Processor (DSP)320and an amplifier330. The storage device160corresponds to, for example, a Random Access Memory (RAM)340and a Read Only Memory (ROM)350. The antenna170corresponds to, for example, an antenna360. The communication interface180corresponds to, for example, a communication interface370.

FIG. 5is a schematic configuration diagram of a base station apparatus in accordance with the first embodiment.

As depicted inFIG. 5, the mobile station apparatus200includes a processing apparatus210, a transmission signal multiplexer220, a radio signal transmitting apparatus230, a radio signal receiving apparatus240, a received signal separator-demodulator250, a storage device260, an antenna270, a portable-recording-medium reading apparatus280, an input apparatus291, and a display apparatus292. The processing apparatus210includes a controlling unit211, a user data decoder212, a control data processing unit213, and an uplink signal generating unit214. The storage device260includes a base station radio resource management file261and a mobile station capability information file262.

The radio signal receiving apparatus240receives a downlink signal transmitted from the base station apparatus100via the antenna270.

The received signal separator-demodulator250separates the uplink signal received by the radio signal receiving apparatus240in accordance with a component carrier determined by the base station apparatus100, and demodulates the downlink signal for each separated component carrier.

The user data decoder212decodes user data included in the downlink signal separated and demodulated by the received signal separator-demodulator250.

The control data processing unit213decodes and transmits control data included in the downlink signal separated and demodulated by the received signal separator-demodulator250to the controlling unit211.

The control data decoded by the control data processing unit213may include data indicating respective component carriers determined by the base station apparatus100for the uplink signal and the downlink signal.

The control data decoded by the control data processing unit213may include data on a frequency band and component carrier that the base station apparatus100is capable of allocating. The control data processing unit213transmits these pieces of data to the controlling unit211and stores them in the base station radio resource management file261of the storage device260.

In addition, the control data decoded by the control data processing unit213may include parameter data for measuring the radio communication quality of the downlink signal. The parameter data includes a list of component carriers that are measurement objects, and data on a time at which a result of a measurement is reported to the base station apparatus. In accordance with these pieces of parameter data, the control data processing unit213measures the radio communication quality of the downlink signal.

The mobile station capability information file262includes data on mobile station capability information of the mobile station apparatus200. The mobile station capability information includes information on a frequency band and component carrier that are capable of being allocated to the mobile station apparatus200. Mobile station capability information includes, for both an uplink signal and a downlink signal, information on a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with.

Data on the mobile station capability information may be written to the mobile station capability information file262during the fabrication of the mobile station apparatus200.

Data on mobile station capability information written during the fabrication may be rewritten after the mobile station apparatus200starts to be operated. For example, the controlling unit211reads, via the portable-recording-medium reading apparatus280, data on mobile station capability information recorded in a portable recording medium such as a flash memory. The controlling unit211replaces data within the mobile station capability information file262with the data on mobile station capability information that has been read.

In accordance with control data received from the control data processing unit213, the controlling unit211controls an operation of the transmission signal multiplexer220in such a manner as to multiplex the uplink signal with the component carrier determined by the base station apparatus100. In accordance with control data received from the control data processing unit213, the controlling unit211controls an operation of the received signal separator-demodulator250in such a manner as to separate and demodulate a downlink signal received from the base station apparatus100.

The uplink signal generating unit214generates an uplink signal to be transmitted from the mobile station apparatus200to the base station apparatus100. The generated uplink signal may include data on mobile station capability information. A generated transmission signal may include data on the radio communication quality of the downlink signal measured by the control data processing unit213.

In accordance with control performed by the controlling unit211, the transmission signal multiplexer220multiplexes the uplink signal generated by the uplink signal generating unit214with the component carrier determined by the base station apparatus100.

The radio signal transmitting apparatus230transmits the uplink signal multiplexed by the transmission signal multiplexer220to the base station apparatus100via the antenna270.

The input apparatus291is an apparatus used by a user to input instructions to the mobile station apparatus200, e.g., a keyboard, touch pad, or mouse. The display apparatus292is an apparatus that displays a result of processing performed by the processing apparatus210, e.g., a liquid crystal display.

FIG. 6is an exemplary hardware configuration diagram of a mobile station apparatus in accordance with the first embodiment.

The processing apparatus210depicted inFIG. 5corresponds to, for example, a CPU410of a mobile station apparatus400depicted inFIG. 6. The transmission signal multiplexer220, the radio signal transmitting apparatus230, the radio signal receiving apparatus240, and the received signal separator-demodulator250correspond to, for example, a DSP420and an amplifier430. The storage device260corresponds to, for example, a RAM440and a ROM450. The antenna270corresponds to an antenna460. The portable-recording-medium reading apparatus280corresponds to, for example, a portable-recording-medium reading apparatus470. The input apparatus291corresponds to, for example, an input apparatus481. The display apparatus292corresponds to, for example, a display apparatus482.

With reference to the radio communication system1, the following will describe an exemplary method used by the base station apparatus100to control allocation of component carriers to be used for a communication with the mobile station apparatus200.

FIG. 7is an exemplary diagram of a radio-resource allocation controlling process flow in accordance with the first embodiment.

When a radio-resource allocation controlling process starts (step S101), the radio-resource allocation controlling unit111performs the processes of steps S102-S109for each of n mobile station apparatuses200that are connection targets of the base station apparatus100(n is an arbitrary integer that is one or higher).

In step S103, the radio-resource allocation controlling unit111determines whether a component carrier is a Primary Component Carrier (PCC) capable of being allocated to a mobile station apparatus200. The primary component carrier is a main component carrier used in a communication between the base station apparatus100and the mobile station apparatus200. A radio resource control connection is established for the primary component carrier.

The following will describe an exemplary process of step S103.

FIG. 8is an explanatory diagram of transmission and reception of a mobile-station-capability-information message. As depicted inFIG. 8, in a radio resource control connection, the base station apparatus100transmits a mobile station capability information request (User Equipment (UE) Capability Enquiry) message M101to a mobile station apparatus200. Upon receipt of the mobile station capability information request message, the mobile station apparatus200transmits a mobile station capability information (UE Capability Information) message M102to the base station apparatus100.

FIG. 9is an exemplary diagram of a mobile station capability message. In the exemplary mobile station capability message depicted inFIG. 9, UE Capability Information-r8, i.e., a structure of mobile station capability information, is indicated in a UE-Capability RAT-Container List illustrated inFIG. 9. In LTE (E-UTRA), UE-EUTRA-Capability defines the UE-Capability RAT-Container List.

FIGS. 10A and 10Bare exemplary diagrams of the configuration of UE-EUTRA-Capability. As depicted inFIG. 10A, UE-EUTRA-Capability includes physical layer parameters (phyLayerParameters) and radio frequency parameters (rf-Parameters), i.e., types of radio access capability parameters of a mobile station apparatus.

As depicted inFIG. 10A, the physical layer parameters include crossCarrierScheduling-r10, simultaneousPUCCH-PUSCH-r10, multiClusterPUSCH-WithinCC-r10, and nonContiguousUL-RA-WithinCC-List-r10. crossCarrierScheduling-r10 defines whether a mobile station apparatus supports cross-carrier scheduling. simultaneousPUCCH-PUSCH-r10 defines whether a mobile station apparatus supports simulcast of a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUSCH). multiClusterPUSCH-WithinCC-r10 defines whether multicluster PUSCH is supported in one component carrier. nonContiguousUL-RA-WithinCC-List-r10 defines whether a radio frequency of a mobile station apparatus supports allocation of discontinuous mobile-station resources in one component carrier.

As depicted inFIG. 10B, the frequency parameters include supportedBandCombination, which defines carrier aggregation supported by the mobile station apparatus and Multiple-Input and Multiple-Output (MIMO) capability. supportedBandCombination includes CA-BandwidthClass-r10, which indicates the maximum number of component carriers each mobile station apparatus is capable of dealing with, and the maximum number of resource blocks each mobile station apparatus is capable of dealing with.

The radio-resource allocation controlling unit111receives data on mobile station capability information from the control data processing unit113. The radio-resource allocation controlling unit111obtains, from the received mobile station capability information, data on a frequency band and component carrier that the mobile station apparatus200is capable of dealing with.

The radio-resource allocation controlling unit111extracts, from the radio resource management file161, component carriers that have not been allocated to the mobile station apparatus200from among the component carriers of the frequency band that the base station apparatus100is capable of allocating.

The radio-resource allocation controlling unit111determines whether the component carriers that have not been allocated to the mobile station apparatus200include a component carrier that the mobile station apparatus200is capable of dealing with (step S103).

When it is determined in step S103that a primary component carrier capable of being allocated to the mobile station apparatus200is not present (“NO” in step S103), the radio-resource allocation controlling unit111shifts to the process of step S104.

In step S104, the radio-resource allocation controlling unit111records the mobile station apparatus200as a mobile station apparatus to which a primary component carrier has been unable to be allocated (an allocation-unable mobile station apparatus). The radio-resource allocation controlling unit111increments an allocation-unable mobile-station apparatus number that starts with 0. Then, the radio-resource allocation controlling unit111ends the processes of steps S102-S109on the mobile station apparatus200and performs the processes of steps S102-S109on a subsequent mobile station apparatus200.

When it is determined in step S103that a primary component carrier capable of being allocated to the mobile station apparatus200is present (“YES” in step S103), the radio-resource allocation controlling unit111shifts to the process of step S105. A primary component carrier capable of being allocated is, for example, a component carrier with an available carrier resource.

In step S105, in consideration of, for example, an estimated channel fluctuation situation and a load balance, the radio-resource allocation controlling unit111determines a primary component carrier to be allocated to the mobile station apparatus200.

In a radio resource control connection established for the primary component carrier, a Radio Resource Control Reconfiguration (RRC Reconfiguration) message transmitted from the base station apparatus100to the mobile station apparatus200may include a measurement configuration message. The measurement configuration message includes a measurement object list indicating component carrier frequencies that are measurement objects, and reporting configurations indicating a time at which a result of a measurement is reported to the base station apparatus100. The radio resource control reconfiguration message includes a list of component carriers that the base station apparatus100is capable of allocating, which are numbered in an ascending order with the component carrier with the lowest frequency band being assigned the lowest number. The mobile station apparatus200receives data included in such messages from the base station apparatus100, and stores the data in the storage device260thereof.

In step S106, the radio-resource allocation controlling unit111increments a PCC-allocated mobile station apparatus number that starts with 0. The PCC-allocated mobile station apparatus indicates the number of mobile station apparatuses200to which a primary component carrier has been allocated.

In step S107, the radio-resource allocation controlling unit111performs a transmission-bandwidth adjacency level value calculation process according to the mobile station capability information received from the mobile station apparatus200.

FIG. 11is an exemplary diagram of a transmission-bandwidth adjacency level value calculation process flow in accordance with the first embodiment.

When the transmission-bandwidth adjacency level value calculation process starts (step S201), then, in step S202, the radio-resource allocation controlling unit111refers to the transmission-bandwidth adjacency-level value management file162so as to determine whether a transmission transmission-bandwidth adjacency level value of the mobile station apparatus200has been calculated.

When it is determined that a transmission-bandwidth adjacency level value of the mobile station apparatus200has been calculated (“YES” in step S202), the radio-resource allocation controlling unit111ends the transmission-bandwidth adjacency level value calculation process on the mobile station apparatus200(step S207).

When it is determined that a transmission-bandwidth adjacency level value of the mobile station apparatus200has not been calculated (“NO” in step S202), the radio-resource allocation controlling unit111shifts to the process of step S203.

In step S203, the radio-resource allocation controlling unit111sets, as an initial transmission-bandwidth adjacency level value, a value indicating that carrier aggregation is unable to be performed. As will be described hereinafter with reference toFIG. 12, the radio-resource allocation controlling unit111sets, for example, 0 to each bit of a three-bit transmission-bandwidth adjacency level value as an initial transmission-bandwidth adjacency level value.

In step S204, the radio-resource allocation controlling unit111refers to mobile-station capability information so as to determine whether the mobile station apparatus200is an apparatus adapted to carrier aggregation (e.g., an apparatus adapted to LTE-A).

When it is determined that the mobile station apparatus200is an apparatus that is not adapted to carrier aggregation (“NO” in step S204), the radio-resource allocation controlling unit111ends the transmission-bandwidth adjacency level value calculation process on the mobile station apparatus200(step S207).

When it is determined that the mobile station apparatus200is an apparatus adapted to carrier aggregation (“YES” in step S204), the radio-resource allocation controlling unit111shifts to the process of step S205. In step S205, the radio-resource allocation controlling unit111determines whether sufficient power to perform a communication using a plurality of component carriers has been supplied from a battery of the mobile station apparatus200.

When it is determined that sufficient power to perform a communication using a plurality of component carriers has not been supplied from the battery (“NO” in step S205), the radio-resource allocation controlling unit111ends the transmission-bandwidth adjacency level value calculation process on the mobile station apparatus200(step S207).

When it is determined that sufficient power to perform a communication using a plurality of component carriers has been supplied from the battery of the mobile station apparatus200(“YES” in step S205), the radio-resource allocation controlling unit111shifts to the process of step S206.

In step S206, the radio-resource allocation controlling unit111refers to mobile station capability information so as to calculate the transmission-bandwidth adjacency level value of the mobile station apparatus200. That is, the radio-resource allocation controlling unit111calculates the transmission-bandwidth adjacency value using data included in mobile-station capability information data and indicating a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with. The data indicating the scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with includes data indicating whether continuous component carriers within the same frequency band are capable of being allocated, whether component carriers of different frequency bands are capable of being allocated, and whether discontinuous component carriers within the same frequency band are capable of being allocated.

FIG. 12is an exemplary diagram of policies on component-carrier allocation indicated by transmission-bandwidth adjacency level values.

In the example depicted inFIG. 12, using data indicating a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with, the radio-resource allocation controlling unit111calculates a transmission-bandwidth adjacency level value X (X is an integer that is 0 or higher) consisting of adjacency level data A, B, and C of three bits.

The adjacency level data A, i.e., the first bit, indicates whether continuous component carriers within the same frequency band are capable of being allocated. When continuous component carriers within the same frequency band are capable of being allocated, the radio-resource allocation controlling unit111sets 1 as the adjacency level data A. When continuous component carriers within the same frequency band are incapable of being allocated, the radio-resource allocation controlling unit111sets 0 as the adjacency level data A.

The adjacency level data B, i.e., the second bit, indicates whether component carriers of different frequency bands are capable of being allocated. When component carriers of different frequency bands are capable of being allocated, the radio-resource allocation controlling unit111sets 1 as the adjacency level data B. When component carriers of different frequency bands are incapable of being allocated, the radio-resource allocation controlling unit111sets 0 as the adjacency level data B.

The adjacency level data C, i.e., the third bit, indicates whether discontinuous component carriers within the same frequency band are capable of being allocated. When discontinuous component carriers within the same frequency band are capable of being allocated, the radio-resource allocation controlling unit111sets 1 as the adjacency level data C. When discontinuous component carriers within the same frequency band are incapable of being allocated, the radio-resource allocation controlling unit111sets 0 as the adjacency level data C.

By setting the 3-bit value, the transmission-bandwidth adjacency level value X, that is classified into eight types as depicted inFIG. 12, indicating policies on component-carrier allocation is calculated. As described above, transmission-bandwidth adjacency level value 0 (000), which indicates that carrier aggregation is incapable of being performed, is set as an initial transmission-bandwidth adjacency level value X.

After a transmission-bandwidth adjacency level value is calculated in step S206, the radio-resource allocation controlling unit111ends the processing series of calculating a transmission-bandwidth adjacency level value for the mobile station apparatus200(step S207).

When the transmission-bandwidth adjacency level value calculation process ends in step S107inFIG. 7, the radio-resource allocation controlling unit111records a calculated transmission-bandwidth adjacency level value in the transmission-bandwidth adjacency-level value management file162.

In step S108inFIG. 7, the radio-resource allocation controlling unit111performs a process of allocating resource blocks using component carriers allocated in step S105.

After the processes of steps S102-S109are performed for each of n mobile station apparatuses200that are connection targets of the base station apparatus100, the radio-resource allocation controlling unit111performs the processes of steps S110-S113for each of m (m is an arbitrary integer that is one or higher) mobile station apparatuses200to which a primary component carrier has been allocated (PCC-allocated mobile station apparatuses).

In step S111, the radio-resource allocation controlling unit111performs a component-carrier allocation process for a mobile station apparatus200.

FIG. 13is an exemplary diagram of a component-carrier allocation process flow in accordance with the first embodiment.

When the component-carrier allocation process starts (step S301), then, in step S302, the radio-resource allocation controlling unit111determines whether a transmission-bandwidth adjacency level value of the mobile station apparatus200is higher than 0 (step S302). That is, the radio-resource allocation controlling unit111determines whether carrier aggregation is capable of being performed for the mobile station apparatus200.

When it is determined that carrier aggregation is incapable of being performed for the mobile station apparatus200(“NO” in step S302), the radio-resource allocation controlling unit111ends the component-carrier allocation process on the mobile station apparatus200(step S312).

When it is determined that carrier aggregation is capable of being performed for the mobile station apparatus200(“YES” in step S302), the radio-resource allocation controlling unit111determines whether the adjacency level data B of the transmission-bandwidth adjacency level value is 1 (step S303). That is, the radio-resource allocation controlling unit111determines whether the mobile station apparatus200is capable of having allocated thereto a component carrier within a frequency band that is different from frequency bands in which allocated primary component carriers are present.

When it is determined that a component carrier within a frequency band that is different from frequency bands of the primary component carriers is incapable of being allocated (“NO” in step S303), the radio-resource allocation controlling unit111shifts to the process of step S306.

On the other hand, when it is determined that a component carrier within a frequency band that is different from frequency bands of the primary component carriers is capable of being allocated (“YES” in step S303), the radio-resource allocation controlling unit111shifts to the process of step S304.

In step S304, the radio-resource allocation controlling unit111refers to the radio resource management file161so as to extract a component carrier that is a candidate for a secondary component carrier (SCC). That is, the radio-resource allocation controlling unit111extracts, from component carriers that have not been allocated to any mobile station apparatus200, a component carrier that is capable of being combined with an allocated primary component carrier in such a manner as to satisfy the determination condition of step S303. A secondary component carrier is a component carrier allocated to a mobile station apparatus200in addition to a primary component carrier through carrier aggregation.

In a case where a component carrier is extracted in step S304, when a secondary component carrier is capable of being allocated (“YES” in step S305), the radio-resource allocation controlling unit111shifts to an allocation execution process in step S311.

In a case where a component carrier is not extracted in step S304, when a secondary component carrier is incapable of being allocated (“NO” in step S305), the radio-resource allocation controlling unit111shifts to the process of step S306.

In step S306, the radio-resource allocation controlling unit111determines whether the adjacency level data C of the transmission-bandwidth adjacency level value is 1. That is, the radio-resource allocation controlling unit111determines whether the mobile station apparatus200is capable of having allocated thereto discontinuous component carriers belonging to the same frequency band as the allocated primary component carrier.

When it is determined that discontinuous component carriers belonging to the same frequency band as the primary component carrier are incapable of being allocated (“NO” in step S306), the radio-resource allocation controlling unit111shifts to the process of step S309.

When it is determined that discontinuous component carriers belonging to the same frequency band as the primary component carrier are capable of being allocated (“YES” in step S306), the radio-resource allocation controlling unit111shifts to the process of step S307.

In step S307, the radio-resource allocation controlling unit111refers to the radio resource management file161so as to extract, as a secondary component carrier and from component carriers that have not been allocated to any mobile station apparatus200, a component carrier that is capable of being combined with an allocated primary component carrier in such a manner as to satisfy the determination condition of step S306.

In a case where a component carrier is extracted in step S307, when a secondary component carrier is capable of being allocated (“YES” in step S308), the radio-resource allocation controlling unit111shifts to the allocation execution process in step S311.

In a case where a component carrier is not extracted in step S307, when a secondary component carrier is incapable of being allocated (“NO” in step S308), the radio-resource allocation controlling unit111shifts to the process of step S309.

In step S309, the radio-resource allocation controlling unit111refers to the radio resource management file161so as to extract a component carrier that is a candidate for a secondary component carrier. That is, the radio-resource allocation controlling unit111extracts, from component carriers that have not been allocated to any mobile station apparatus200, component carriers that are continuous with the allocated primary component carriers within the same frequency band.

In a case where a component carrier is extracted in step S309, when a secondary component carrier is capable of being allocated (“YES” in step S310), the radio-resource allocation controlling unit111shifts to the allocation execution process in step S311.

In step S311, in consideration of, for example, an estimated channel fluctuation situation and a load balance, the radio-resource allocation controlling unit111determines a secondary component carrier capable of being optimally combined with a primary component carrier from among the extracted candidates for a secondary component carrier. Then, the radio-resource allocation controlling unit111ends the component-carrier allocation process, i.e., the processing series depicted inFIG. 13.

In a case where a component carrier is not extracted in step S309, when a secondary component carrier is incapable of being allocated (“NO” in step S310), the radio-resource allocation controlling unit111ends the component-carrier allocation process, i.e., the processing series depicted inFIG. 13. That is, the radio-resource allocation controlling unit111ends the processing series depicted inFIG. 13without allocating a secondary component carrier to the mobile station apparatus200.

As is clear from the descriptions above, use of the transmission-bandwidth adjacency level value in accordance with any of the embodiments enables a combination of component carriers capable of being allocated to a mobile station apparatus to be efficiently extracted from frequency bands and component carriers that a base station apparatus is capable of allocating. Accordingly, use of the transmission-bandwidth adjacency level value in accordance with any of the embodiments enables allocation of component carriers to mobile station apparatuses to be determined quickly and efficiently.

In step S112inFIG. 7, the radio-resource allocation controlling unit111performs a process of allocating resource blocks using the component carriers allocated in step S111.

After the processes of steps S102-S113are performed for each of m mobile station apparatuses200that are PCC-allocated mobile station apparatuses, the radio-resource allocation controlling unit111shifts to a component-carrier reallocation process in step S114.

FIG. 14is an exemplary diagram of a component-carrier reallocation process flow in accordance with the first embodiment.

When the component-carrier reallocation process starts (step S401), the radio-resource allocation controlling unit111performs the processes of steps S402-S409for each of the mobile station apparatuses200recorded in step S103as a mobile station apparatus to which a primary component carrier is incapable of being allocated. For convenience, a mobile station apparatus200recorded in step S103as a mobile station apparatus to which a primary component carrier is incapable of being allocated will hereinafter be referred to as an allocation-unable mobile station apparatus200.

In step S403, the radio-resource allocation controlling unit111determines whether a mobile station apparatus200is present to which a component carrier that the allocation-unable mobile station apparatus200is capable of dealing with has been allocated as a secondary component carrier. For convenience, a mobile station apparatus200to which a component carrier that an allocation-unable mobile station apparatus200is capable of dealing with has been allocated as a secondary component carrier will hereinafter be referred to as an allocation-completed mobile station apparatus200.

When it is determined in step S403that an allocation-completed mobile station apparatus200is not present (“NO” in step S403), the radio-resource allocation controlling unit111shifts to the process of step S409. The radio-resource allocation controlling unit111performs the processes of steps S402-S409for the allocation-unable mobile station apparatus200without allocating a component carrier.

When it is determined in step S403that an allocation-completed mobile station apparatus200is present (“YES” in step S403), the radio-resource allocation controlling unit111shifts to the process of step S404.

In steps S404-S406, processing is performed for each allocation-completed mobile station apparatus200to which a component carrier that the allocation-unable mobile station apparatus200is capable of dealing with has been allocated as a secondary component carrier.

In step S405, the radio-resource allocation controlling unit111determines whether a secondary component carrier allocated to an allocation-completed mobile station apparatus200is capable of being replaced with another component carrier.

In particular, the radio-resource allocation controlling unit111extracts, from the radio resource management file161, component carriers that have not been allocated to any mobile station apparatus200from among the component carriers of the frequency band that the base station apparatus100is capable of allocating. The radio-resource allocation controlling unit111also refers to the mobile station capability information management file163so as to obtain a component carrier of a frequency band that an allocation-completed mobile station apparatus200is capable of dealing with. The radio-resource allocation controlling unit111determines whether the extracted component carriers that have not been allocated include a component carrier that the allocation-completed mobile station apparatus200is capable of dealing with.

When it is determined in step S405that a component carrier that the allocation-completed mobile station apparatus200is capable of dealing with is not present (“NO” in step S405), the radio-resource allocation controlling unit111shifts to the process of step S406.

In step S405, the radio-resource allocation controlling unit111ends the processing on the allocation-completed mobile station apparatus200. Then, the radio-resource allocation controlling unit111returns to the process of step S404and performs the process of step S405on another allocation-completed mobile station apparatus200.

When it is determined in step S405that a component carrier that the allocation-completed mobile station apparatus200is capable of dealing with is present (“YES” in step S405), the radio-resource allocation controlling unit111shifts to the process of step S407.

In step S407, the radio-resource allocation controlling unit111reallocates a secondary component carrier to the allocation-completed mobile station apparatus200. That is, the radio-resource allocation controlling unit111replaces the secondary component carrier of the allocation-completed mobile station apparatus200with a component carrier extracted in step S405, i.e., a component carrier that has not been allocated and that the allocation-completed mobile station apparatus200is capable of dealing with.

In step S408, the radio-resource allocation controlling unit111allocates the component carrier that has become unused as a result of the reallocation process in step S407as a primary component carrier of an allocation-unable mobile station apparatus200.

When the processes of steps S402-S409have been performed for all allocation-unable mobile station apparatuses200, the radio-resource allocation controlling unit111ends the component-carrier reallocation process, i.e., the processing series depicted inFIG. 14(step S410).

When the component-carrier reallocation process ends in step S114ofFIG. 7, then, in step S115, the radio-resource allocation controlling unit111performs a process of allocating resource blocks using the component carriers allocated in step S114.

When the resource-block allocation process ends in step S115ofFIG. 7, the radio-resource allocation controlling unit111ends the radio-resource allocation controlling process, i.e., the processing series depicted inFIG. 7(step S116).

The radio-resource allocation controlling process series described above with reference toFIGS. 7-14may be repeatedly performed on a predetermined time cycle. In the repetitive performing of the radio-resource allocation controlling process series, the processes of steps S103-S105are skipped for mobile station apparatuses200to which a primary component carrier has already been allocated. The transmission-bandwidth adjacency level value calculation process in step S107is skipped for a mobile station apparatus200for which a transmission-bandwidth adjacency level value has been calculated. In the component-carrier allocation process in step S111, a secondary component carrier may be determined in consideration of a radio communication quality for each component carrier.

In the manner described above, repeatedly performing the radio-resource allocation controlling process series described above may control component carriers of frequency bands that the base station apparatus100is capable of allocating, in a manner such that the component carriers are able to be optimally allocated in accordance with the communication capabilities of the individual mobile station apparatuses200.

As described above, according to the radio communication system in accordance with the first embodiment, the base station apparatus may control allocation of radio resources in accordance with the communication capability of each connection-target mobile station apparatus, i.e., in accordance with whether the mobile station apparatus is capable of performing carrier aggregation.

According to the radio communication system in accordance with the first embodiment, the base station apparatus may control allocation of a plurality of component carriers in consideration of a scenario for carrier aggregation that a connection-target mobile station apparatus is capable of dealing with.

In addition, according to the radio communication system in accordance with the first embodiment, the base station apparatus may perform a process of reallocating component carriers to other mobile station apparatuses so as to perform allocation control for a mobile station apparatus to which a component carrier has not been allocated.

Second Embodiment

As described above with reference toFIGS. 7-14, in the first embodiment, the base station apparatus100calculates the transmission-bandwidth adjacency level value of each mobile station apparatus200.

In the meantime, each mobile station apparatus200may calculate a transmission-bandwidth adjacency level value.

In the second embodiment, the controlling unit211of the mobile station apparatus200reads data on mobile station capability information of the mobile station apparatus200from the mobile station capability information file262within the storage device260. In a process similar to the process of step S206ofFIG. 11, the controlling unit211calculates transmission-bandwidth adjacency level values classified into eight types as depicted inFIG. 12and indicating policies on component-carrier allocation.

For example, as illustrated inFIG. 8, a mobile station apparatus200receives a mobile-station capability enquiry (UE Capability Enquiry) message M101from the base station apparatus100through a radio resource control connection. The mobile station apparatus200transmits a mobile station capability information (UE capability information) message M102that includes calculated transmission-bandwidth adjacency level value data to the base station apparatus100.

A radio resource controlling process based on the radio communication system in accordance with the second embodiment may be similar to the process of the first embodiment described above, other than the processes that the mobile station apparatus200calculates and transmits a transmission-bandwidth adjacency level value to the base station apparatus100.

The radio communication system in accordance with the second embodiment provides an advantage similar to the advantage of the radio communication system in accordance with the first embodiment described above. The radio communication system in accordance with the second embodiment may decrease the processing burden on a base station apparatus to which many mobile station apparatuses are connected, and may achieve an enhanced processing speed of the base station apparatus, and decreased complexity of the circuit configuration.

Third Embodiment

As described above, in the first embodiment, the base station apparatus100calculates a transmission-bandwidth adjacency level value of each mobile station apparatus200. In the second embodiment, each mobile station apparatus200calculates and transmits a transmission-bandwidth adjacency level value thereof to the base station apparatus100.

Meanwhile, the transmission-bandwidth adjacency level value of a mobile station apparatus200may be stored in the mobile station capability information file262of the storage device260during the process of fabricating the mobile station apparatus200. Data on the transmission-bandwidth adjacency level value stored in the mobile station capability information file262may be rewritten after the mobile station apparatus200starts to be operated.

In the third embodiment, an arbitrary calculation processing apparatus as depicted inFIG. 15, e.g., a computer, calculates the transmission-bandwidth adjacency level value of a mobile station apparatus200using data on mobile station capability information of the mobile station apparatus200. Data on the mobile station capability information used for the calculation is the data described above indicating a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with.

FIG. 15is an exemplary hardware configuration diagram of a computer.

As depicted inFIG. 15, a computer500includes a Central Processing Unit (CPU)501, i.e., an exemplary processor, a main storage device502such as a RAM, and an auxiliary storage device503such as a hard disk drive. The computer500also includes an input apparatus504such as a keyboard or a mouse, and a display apparatus505such as a liquid crystal display. In addition, the computer500includes a portable-recording-medium read and write apparatus506that writes data to and reads data from a portable recording medium such as a flash memory, and a communication interface507to be connected to a communication network such as the Internet. The elements501-507included in the computer500are connected to each other by a bus508.

Data on mobile station capability information of the mobile station apparatus200may be input via the input apparatus504. Alternatively, the CPU501may read data on mobile station capability information of the mobile station apparatus200from a portable recording medium via the portable-recording-medium read and write apparatus506. The data on mobile station capability information that has been input or read is stored in the main storage device502. Using data on mobile station capability information stored in the main storage device502, the CPU501calculates a transmission-bandwidth adjacency level value in accordance with the embodiment described above with reference toFIGS. 11 and 12. The calculated transmission-bandwidth adjacency level value may be displayed on the display apparatus505.

Together with data on mobile station capability information, data on the transmission-bandwidth adjacency level value calculated by the CPU501may be recorded in the mobile station capability information file262during the process of fabricating the mobile station apparatus200.

Together with data on mobile station capability information, data on the transmission-bandwidth adjacency level value calculated by the CPU501may be stored in a portable recording medium such as a flash memory via the portable-recording-medium read and write apparatus506. The controlling unit211reads the data recorded in the portable recording medium via the portable-recording-medium reading apparatus280. For example, the controlling unit211reads data on mobile station capability information and on a transmission-bandwidth adjacency level value recorded in the portable recording medium. The controlling unit211updates data within the mobile station capability information file262with these pieces of read data.

The radio communication system in accordance with the third embodiment provides an advantage similar to the advantage of the radio communication system in accordance with the first embodiment described above. The radio communication system in accordance with the third embodiment may decrease the processing burdens on a base station apparatus and mobile station apparatuses, and may achieve enhanced processing speeds of the base station apparatus and the mobile station apparatuses, and decreased complexity in the circuit configurations.

Fourth Embodiment

In the first to third embodiments, transmission-bandwidth adjacency level values are calculated according to data indicating a scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with. As described above, the data indicating the scenario for carrier aggregation that the mobile station apparatus200is capable of dealing with includes data indicating whether continuous component carriers within the same frequency band are capable of being allocated, whether component carriers of different frequency bands are capable of being allocated, and whether discontinuous component carriers within the same frequency band are capable of being allocated.

By contrast, a component-carrier allocation request of individual mobile station apparatuses200may be reflected in transmission-bandwidth adjacency level values.

In a radio communication system in accordance with the fourth embodiment, the mobile station apparatus200obtains component-carrier allocation request information as a portion of mobile station capability information (UE capability information).

Component-carrier allocation request information is, for example, a policy on component-carrier allocation requested by the mobile station apparatus200.

The policy on component-carrier allocation is represented by, for example, two-bit data in accordance with the following classifications. That is, 0 indicates “no allocation request” and 1 indicates “request for allocation of a plurality of component carriers within the same frequency band”. 2 indicates “request for allocation of a plurality of component carriers of different frequency bands”, and 3 indicates “request for allocation of discontinuous component carriers within the same frequency band”.

A combination of requested frequency bands, requested component carriers, and request for the number of Multiple-Input and Multiple-Output (MIMO) streams may be added to component-carrier allocation request information.

A combination of requested frequency bands may be expressed by data of a predetermined bit count in accordance with the number of combinations of frequency bands prepared in advance. For example, each combination of frequency bands prepared in advance is assigned a corresponding number. A correlation between a combination of frequency bands prepared in advance and an assigned number is shared between the mobile station apparatus200and the base station apparatus100in advance. In regard to component-carrier allocation request information related to combinations of requested frequency bands indicates, in one example, “no request for combination” is expressed as 0, and each “combination of requested frequency bands” is expressed as a corresponding number.

A requested component carrier may be represented by data of a predetermined bit count in accordance with the number of component carriers that the mobile station apparatus200is capable of dealing with. For example, all component carriers that the mobile station apparatus200is capable of dealing with are assigned a number in an ascending order with the component carrier with the lowest frequency band being assigned the lowest number. A correlation between a component carrier and an assigned number is shared between the mobile station apparatus200and the base station apparatus100in advance. In regard to component-carrier allocation information related to requested component carriers indicates, in one example, “no request for component carrier” is expressed as 0, and each “requested component carrier” is expressed as a corresponding assigned number.

A number of MIMO streams that are requested may be expressed by data of a predetermined bit count in accordance with the number of antennas of the mobile station apparatus200. In regard to component-carrier allocation request information related to the number of MIMO streams that are requested, in one example, “no request” is expressed as 0, and the number of used antennas that are requested is expressed as “the number of MIMO streams that are requested”.

A mobile station apparatus200transmits component-carrier allocation request information to the base station apparatus100.

FIG. 16is an explanatory diagram of an exemplary process of determining and transmitting component-carrier allocation request information.

As depicted inFIG. 16, in a radio resource control connection, the base station apparatus100transmits a radio resource control connection reconfiguration (RRC Control Connection Reconfiguration) message M201to the mobile station apparatus200. The radio resource control connection reconfiguration message M201includes a Measurement Configuration message.

The measurement configuration message includes a list of measurement objects indicating the frequencies of measurement-object component carriers, and a list of reporting configurations indicating a time at which a result of a measurement is reported to the base station apparatus100. The radio resource control reconfiguration message includes a list of component carriers that the base station apparatus100is capable of allocating, which are numbered in ascending order with the component carrier with the lowest frequency band being assigned the lowest number. Data included in those messages is stored in the storage device260.

The mobile station apparatus200transmits a radio resource control reconfiguration completion (RRC Connection Reconfiguration Complete) message M202to the base station apparatus100.

The control data processing unit213measures signal levels of individual component carriers of cells around a mobile station apparatus200. Alternatively, the control data processing unit213may measure signal levels of component carriers of a measurement-object list included in the measurement configuration message. The measured signal levels include, for example, Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRP).

The controlling unit211refers to the measured signal levels of individual components so as to determine a combination of component carriers having a high signal level as a policy on requested component-carrier allocation. The controlling unit211determines a component carrier having a high signal level from among the signal levels of the measured components as a requested component carrier (secondary component carrier).

The mobile station apparatus200transmits a radio quality measurement report (Measurement Report) message M203that includes determined component-carrier allocation information to the base station apparatus100.

Using a transmission-bandwidth adjacency level value reflecting the component-carrier allocation request information received by the mobile station apparatus200, the base station apparatus100performs control for allocating component carries to mobile station apparatuses200.

A specific process flow of the radio-resource allocation control in accordance with the fourth embodiment may be similar to the process flow of the radio-resource allocation control in accordance with the first embodiment described above with reference toFIGS. 7-14, except for adding the processes bellow.

In the process of determining a primary component carrier in step S105, a primary component carrier may be determined according to a request for primary-component-carrier allocation indicated by component-carrier allocation request information in addition to the channel fluctuation situation and the like.

In the transmission-bandwidth adjacency level value calculation process in step S107, a transmission-bandwidth adjacency level value is calculated that reflects component-carrier allocation request information.

In particular, in step S206, at a higher-order byte than adjacency level data A, B, and C indicating scenarios for carrier aggregation that a mobile station apparatus200is capable of dealing with, allocation request data D of a predetermined bit reflecting details of component-carrier allocation request information is added. In the example described above, when, for example, component-carrier allocation request information consists only of a policy on requested allocation of component carriers, the allocation request data D is data of two bits.

In the component-carrier allocation process in step S111, a secondary component carrier is allocated in accordance with a transmission-bandwidth adjacency level value reflecting component-carrier allocation request information.

In particular, when it is determined in step S302that a transmission-bandwidth adjacency level value is higher than 0 (“YES” in step S302), it is determined, prior to the processes of step S303and the following steps, whether a component carrier indicated by the allocation request data D is capable of being allocated. When the component carrier indicated by the allocation request data D is capable of being allocated, the flow shifts to step S311, where the component carrier indicated by the allocation request data D is allocated as a secondary component carrier. When the component carrier indicated by the allocation request data D is incapable of being allocated, the flow shifts to step S303and the following steps, and the allocation process is performed according to the adjacency level data A, B, and C.

In the component-carrier reallocation process in step S114, reallocation processes are performed according to component-carrier allocation request information of an allocation-unable mobile station apparatus200and component-carrier allocation request information of an allocation-completed mobile station apparatus200.

In particular, in the fourth embodiment, instead of the reallocation determination processes in step S405, the reallocation determination process of steps S405-1and S405-2depicted inFIG. 17is performed.

FIG. 17is an exemplary diagram of a reallocation determination process flow in accordance with the fourth embodiment.

In a first reallocation determination process in step S405-1, it is determined whether a reallocation process is capable of being performed for a component carrier indicated by component-carrier allocation request information of the allocation-unable mobile station apparatus200. That is, it is determined whether reallocation of a component carrier of another allocation conforming to component-carrier allocation request information of an allocation-completed mobile station apparatus200is capable of being performed.

When it is determined in step S405-1that reallocation is capable of being performed (“YES” in step S405-1), the flow shifts to step S407. In step S407, a component carrier that has not been allocated and that has been determined to be capable of being reallocated is allocated as a new secondary component carrier of the allocation-completed mobile station apparatus200. In step S408, a component carrier that has become unallocated as a result of the process of step S407is allocated to an allocation-unable mobile station apparatus200. That is, a component carrier indicated by component-carrier allocation request information of the allocation-unable mobile station apparatus200is allocated to the allocation-unable mobile station apparatus200.

Meanwhile, when it is determined in step S405-1that reallocation is incapable of being performed (“NO” in step S405-1), the flow shifts to a second reallocation determination process in step S405-2.

In step S405-2, it is determined whether a component carrier that is different from the component carrier indicated by component-carrier allocation request information and that the allocation-unable mobile station apparatus200is capable of dealing with is capable of being reallocated. That is, it is determined whether reallocation of a component carrier of another allocation conforming to component-carrier allocation request information of an allocation-completed mobile station apparatus200is capable of being performed.

When it is determined in step S405-2that reallocation is capable of being performed (“YES” in step S405-2), the flow shifts to step S407. In step S407, a component carrier that has not been allocated and that has been determined to be capable of being reallocated is allocated as a new secondary component carrier of the allocation-completed mobile station apparatus200. In step S408, a component carrier that has become unallocated as a result of the process of step S407is allocated to an allocation-unable mobile station apparatus200. That is, a component carrier other than the component carrier indicated by component-carrier allocation request information and that the allocation-unable mobile station apparatus200is capable of dealing with is allocated to the allocation-unable mobile station apparatus200.

The radio communication system in accordance with the fourth embodiment provides an advantage similar to the advantage of the radio communication system in accordance with the first embodiment described above. The radio communication system in accordance with the fourth embodiment enables a base station apparatus to perform radio-resource allocation control in which component-carrier allocation request of each mobile station apparatus is reflected.

Fifth Embodiment

In the radio communication system in accordance with the fourth embodiment, the base station apparatus100receives component-carrier allocation request information from a mobile station apparatus200as a portion of mobile station capability information. The base station apparatus100calculates a transmission-bandwidth adjacency level value reflecting the received component-carrier allocation information.

By contrast, in one possible configuration, the mobile station apparatus200transmits, to the base station apparatus100, mobile station capability information that includes a transmission-bandwidth adjacency level value reflecting component-carrier allocation request information.

In the radio communication system in accordance with the fifth embodiment, the controlling unit211determines information details of component-carrier allocation request information, as described above with reference toFIG. 16. A determined information detail is, for example, a policy on requested allocation of component carriers. The controlling unit211calculates a transmission-bandwidth adjacency level value reflecting the determined information details. The calculation process performed by the controlling unit211is similar to the calculation process performed by the radio-resource allocation controlling unit111in accordance with the fourth embodiment. The controlling unit211transmits, to the base station apparatus100, a mobile-station-capability information (UE capability information) message that includes the transmission-bandwidth adjacency level value reflecting component-carrier allocation request information.

The radio communication system in accordance with the fifth embodiment provides an advantage similar to the advantage of the radio communication system in accordance with the fourth embodiment described above. The radio communication system in accordance with the fifth embodiment may decrease the processing burden on a base station apparatus in calculating a transmission-bandwidth adjacency level value reflecting component-carrier allocation request information. That is, the radio communication system may decrease the processing burden on abase station apparatus to which many mobile station apparatuses are connected, and may achieve an enhanced processing speed of the base station apparatus, and decreased complexity of the circuit configuration.

Sixth Embodiment

The radio resource controlling processes in accordance with the first to fifth embodiments performed by the base station apparatus100and the mobile station apparatus200may be performed by a computer within each of these apparatuses. That is, a radio resource controlling process in accordance with an embodiment may also be performed by individual computers that are present within the base station apparatus100and the mobile station apparatus200and that are operated in accordance with a radio resource controlling program defining the procedures of the radio resource controlling process in accordance with such an embodiment.

The hardware configurations of individual computers implemented in the base station apparatus100and the mobile station apparatus200may be similar to, for example, the computer depicted inFIG. 15.

A radio resource controlling program in accordance with an embodiment is recorded in a portable recording medium such as a magnetic disk, an optical disk, or a magnetic optical disk. The radio resource controlling program recorded in the portable recording medium is read via the portable-recording-medium read and write apparatus506and is installed on the auxiliary storage device503. Alternatively, a radio resource controlling program in accordance with an embodiment may be stored in another computer apparatus (not illustrated) and may be obtained and installed on the auxiliary storage device503by the computer500via the communication interface507.

The CPU501executes a radio resource controlling program in accordance with an embodiment loaded from the auxiliary storage device503into the main storage device502.

The radio communication system in accordance with the sixth embodiment may provide an advantage similar to the advantage of the radio communication system in accordance with the first to fifth embodiments described above.

Embodiments enable a radio base station apparatus to control allocation of radio resources in accordance with communication capabilities of individual connection-target mobile station apparatuses.