Patent Description:
Wireless communication environment in recent years faces a problem of a rapid increase in data traffic. Hence, in 3GPP, installing a large number of small cells in a macro cell to increase network density, thereby distributing traffic, has been under study. Such a technology utilizing small cells is referred to as small cell enhancement. Note that small cells may conceptually include various types of cells (e.g., a femto cell, a nano cell, a pico cell, a micro cell, and the like) that are smaller than a macro cell and are arranged to overlap a macro cell. However, an increase in small cells may cause an increase in inter-cell interference and lead to large power consumption of the entire network; hence, in Patent Literature <NUM> below, a technology of adaptively setting a small cell in a sleep state has been developed.

In addition, as one way to expand radio resources, utilization of a frequency band of <NUM> or more, which is called a milli-wave zone, has been under study. However, since the milli-wave zone has strong straightness and exhibits large radio propagation attenuation, utilization in a small cell smaller than a macro cell is expected. Under a situation in which the broad frequency band of the milli-wave zone is not entirely used, part of the frequency band can be turned on/off in the small cell. Further, in regard to a frequency band in an off state, a signal for measurement to enable measurement of quality on the terminal apparatus side is transmitted from a base station.

However, transmitting a signal for measurement using the whole of the broad frequency band of the milli-wave zone imposes a large burden on the base station side in terms of electric power. In addition, measuring a signal for measurement in the whole of the broad frequency band imposes a large burden also on the terminal apparatus side in terms of electric power. Therefore, it is desirable to provide a mechanism that enables a signal for measurement to be transmitted in a partial frequency band and measured on the terminal apparatus side.

According to the present disclosure, there are provided apparatuses and methods according to the appended claims.

According to the present disclosure, a mechanism that enables a signal for measurement to be transmitted in a partial frequency band and measured on the terminal apparatus side is provided.

Note that description will be given in the following order.

<FIG> is an explanatory diagram for describing an overview of a system <NUM> according to an embodiment of the present disclosure. As illustrated in <FIG>, the system <NUM> includes a wireless communication apparatus <NUM>, a terminal apparatus <NUM>, and a communication control apparatus <NUM>.

In the example of <FIG>, the communication control apparatus <NUM> is a macro cell base station. The macro cell base station <NUM> provides a wireless communication service for one or more terminal apparatuses <NUM> located inside a macro cell <NUM>. The macro cell base station <NUM> is connected to a core network <NUM>. The core network <NUM> is connected to a packet data network (PDN) <NUM> via a gateway apparatus (not illustrated). The macro cell <NUM> may be operated in accordance with any wireless communication scheme, such as long term evolution (LTE), LTE-advanced (LTE-A), GSM (registered trademark), UMTS, W-CDMA, CDMA200, WiMAX, WiMAX2, or IEEE802. <NUM>, for example. Note that without being limited to the example of <FIG>, a control node in the core network <NUM> or the PDN <NUM> (a host node of the macro cell base station) may have a function of controlling wireless communication in a macro cell and a small cell in a cooperative manner. Note that the macro cell base station may also be referred to as a Macro eNodeB.

The wireless communication apparatus <NUM> is a small cell base station that operates a small cell <NUM>. Typically, the small cell base station <NUM> is authorized to allocate radio resources to the terminal apparatus <NUM> that connects to the own apparatus. However, allocation of radio resources may be at least partially entrusted to the communication control apparatus <NUM> for cooperative control. A wireless communication apparatus <NUM> may be a small cell base station fixedly installed as illustrated in <FIG>, or may be a dynamic access point (AP) that dynamically operates the small cell <NUM>. Note that the small cell base station may also be referred to as a pico eNB or a Femto eNB.

The terminal apparatus <NUM> connects to the macro cell base station <NUM> or the small cell base station <NUM> to enjoy a wireless communication service. For example, the terminal apparatus <NUM> that connects to the small cell base station <NUM> receives a control signal from the macro cell base station <NUM>, and receives a data signal from the small cell base station <NUM>. The terminal apparatus <NUM> is also called a user. The user may also be called user equipment (UE). Here, UE may be UE defined in LTE or LTE-A, or more generally may mean communication equipment.

A technology related to carrier aggregation prescribed in LTE Release <NUM> is described below.

Carrier aggregation is a technology of improving throughput of communication by forming a communication channel between a base station and a terminal apparatus by aggregating a plurality of unit frequency bands supported in LTE, for example. Individual unit frequency bands included in one communication channel formed by carrier aggregation are referred to as component carriers (CCs). Here, a CC may be a CC defined in LTE or LTE-A, or more generally may mean a unit frequency band.

In LTE Release <NUM>, it is possible to aggregate five CCs at maximum. In addition, one CC has a width of <NUM>. Note that the CCs to be aggregated may be arranged consecutively on a frequency axis, or may be arranged apart from each other. Moreover, which CC to aggregate and use can be set for each terminal apparatus.

The plurality of CCs that are aggregated are classified into one primary component carrier (PCC) and a secondary component carrier (SCC) other than the PCC. The PCC is different for each terminal apparatus. Since the PCC is the most important CC, it is desirable that the CC with the most stable communication quality be selected.

<FIG> is an explanatory diagram for describing component carriers. In the example illustrated in <FIG>, a situation in which two pieces of UE use some of five CCs in aggregation is illustrated. In detail, UE1 uses CC1, CC2, and CC3 in aggregation, and UE2 uses CC2 and CC4 in aggregation. Moreover, the PCC of UE1 is CC2. The PCC of UE2 is CC4.

Here, selection of a PCC is dependent on implementation. An SCC is changed by deleting the SCC and adding another SCC. That is, it is difficult to directly change an SCC.

In the case where a terminal apparatus transitions from an RRC Idle state to an RRC Connected state, the CC in which connection is established first is the PCC. A change of the PCC is performed through a procedure similar to handover.

A PCC is formed through a procedure called Connection establishment. This procedure is a procedure started with a request from the terminal apparatus side used as a trigger.

A PCC is changed through a procedure called Connection Reconfiguration. This procedure includes transmission and reception of handover messages. This procedure is a procedure started from the base station side.

An SCC is added through a procedure called Connection Reconfiguration. This procedure is a procedure started from the base station side. An SCC is added to a PCC and belongs to the PCC. Adding an SCC is also referred to as activating an SCC.

An SCC is deleted through a procedure called Connection Reconfiguration. This procedure is a procedure started from the base station side. In this procedure, a specific SCC designated in a message is deleted. Note that deletion of an SCC is performed also through a procedure called Connection Re-establishment. This procedure is a procedure started from the terminal apparatus side. Through this procedure, all the SCCs are deleted. Deleting an SCC is also referred to as deactivating an SCC.

A PCC has a special role different from that of an SCC. For example, transmission and reception of NAS signaling in Connection establishment is performed only in the PCC. In addition, transmission of a physical uplink control channel (PUCCH) is performed only in the PCC. Note that examples of an uplink control signal include ACK or NACK indicating success for failure of reception for data transmitted in downlink, a scheduling request, and the like. Moreover, a procedure from detection of Radio Link Failure to Connection Re-establishment is also performed only in the PCC.

In regard to carrier aggregation, a technology prescribed in LTE Release <NUM> is described below.

In LTE Release <NUM>, a scenario is shown in which a macro cell base station and a small cell base station use different frequencies. For example, a frequency of approximately <NUM> may be allocated to the macro cell base station, and a high frequency such as <NUM> may be allocated to the small cell base station.

Moreover, LTE Release <NUM> prescribes that at least part of a frequency band is intermittently turned on/off (i.e., brought into an on state/an off state) by a base station. The first purpose of this is to reduce power consumption by small cell base stations, which are large in number. In addition, the second purpose is to reduce interference by turning off a frequency band that does not need to be used.

<FIG> is an explanatory diagram for describing on/off of component carriers. <FIG> illustrates examples of CCs provided by a base station; CC1 and CC2 are in an on state, and CC3 is in an off state. A terminal apparatus can activate a CC in an on state, thereby performing uplink communication or downlink communication using the CC with the base station. That is, CCs in an on state are candidates for CCs that can be activated. In regard to CC3 in an off state, the base station transmits a signal for measurement to enable measurement of quality on the terminal apparatus side. This signal for measurement may also be called a discovery reference signal (DRS). Here, a DRS may be a DRS defined in LTE or LTE-A, or more generally may mean a signal for measurement (e.g., a discovery signal). The terminal apparatus measures quality of a downlink channel of CC3 in an off state with the DRS, and reports a measurement result to a cell base station. The base station determines whether or not to turn on CC3 in an off state on the basis of this measurement result.

<FIG> is an explanatory diagram for describing a DRS. <FIG> schematically illustrates transmission timing of the DRS. As illustrated in <FIG>, the DRS may be transmitted intermittently and periodically. A cycle may be <NUM> milliseconds (ms), for example. In addition, this cycle is variable, and cycle setting information is reported from the base station to the terminal apparatus. In contrast, a cell specific reference signal (CRS), which is a reference signal, is inserted into all sub-frames, and its cycle is <NUM>, for example.

<FIG> is a sequence diagram illustrating an example of the flow of a process related to measurement of a DRS. As illustrated in <FIG>, first, the base station transmits a DRS (step S12). On that occasion, the base station is assumed to transmit the DRS periodically with a transmission cycle and a CC set in common with the terminal apparatus preliminarily, in the CC in an off state. The terminal apparatus performs measurement of the DRS in accordance with preliminary setting (step S14), and transmits the measurement result to the base station (step S16). In this specification, measurement of the DRS is also referred to as measurement, and the measurement result is also referred to as a measurement report. Note that the measurement report is transmitted using uplink of a CC in an on state. The base station determines on/off of a CC on the basis of the measurement report (step S18). For example, the base station turns on a CC in an off state that is to be turned on, and turns off a CC in an on state that is to be turned off.

In typical implementation, not a macro cell base station but a small cell base station turns on/off component carriers. Therefore, the following description is given in regard to a small cell base station that turns on/off component carriers. As a matter of course, this does not narrow the scope of application of the present technology, and the present technology is also applicable to a macro cell base station and the like.

Next, the configuration of the small cell base station <NUM> according to an embodiment of the present disclosure will be described with reference to <FIG> is a block diagram illustrating an example of the configuration of the small cell base station <NUM> according to an embodiment of the present disclosure. Referring to <FIG>, the small cell base station <NUM> includes an antenna unit <NUM>, a wireless communication unit <NUM>, a network communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The antenna unit <NUM> radiates a signal output by the wireless communication unit <NUM>, in the form of radio waves, into space. The antenna unit <NUM> also converts radio waves in space into a signal, and outputs the signal to the wireless communication unit <NUM>.

The wireless communication unit <NUM> transmits and receives signals. For example, the wireless communication unit <NUM> transmits a downlink signal to the terminal apparatus and receives an uplink signal from the terminal apparatus.

The network communication unit <NUM> transmits and receives information. For example, the network communication unit <NUM> transmits information to other nodes and receives information from other nodes. For example, the other nodes include other base stations and a core network node.

The storage unit <NUM> temporarily or permanently stores a program and various data for operation of the small cell base station <NUM>.

The processing unit <NUM> provides various functions of the small cell base station <NUM>. The processing unit <NUM> includes a transmission processing unit <NUM> and a reporting unit <NUM>. Note that the processing unit <NUM> may further include a structural element other than these structural elements. That is, the processing unit <NUM> may perform operation other than the operation of these structural elements.

The operation of the transmission processing unit <NUM> and the reporting unit <NUM> will be described in detail later.

Next, an example of the configuration of the terminal apparatus <NUM> according to an embodiment of the present disclosure will be described with reference to <FIG> is a block diagram illustrating an example of the configuration of the terminal apparatus <NUM> according to an embodiment of the present disclosure. Referring to <FIG>, the terminal apparatus <NUM> includes an antenna unit <NUM>, a wireless communication unit <NUM>, a storage unit <NUM> and a processing unit <NUM>.

The wireless communication unit <NUM> transmits and receives signals. For example, the wireless communication unit <NUM> receives a downlink signal from the base station and transmits an uplink signal to the base station.

The storage unit <NUM> temporarily or permanently stores a program and various data for operation of the terminal apparatus <NUM>.

The processing unit <NUM> provides various functions of the terminal apparatus <NUM>. The processing unit <NUM> includes a measurement processing unit <NUM> and a requesting unit <NUM>. Note that the processing unit <NUM> may further include a structural element other than these structural elements. That is, the processing unit <NUM> may perform operation other than the operation of these structural elements.

The operation of the measurement processing unit <NUM> and the requesting unit <NUM> will be described in detail later.

A milli-wave zone has a broad frequency band. Transmitting a DRS using all the CCs included in the broad frequency band of the milli-wave zone imposes a large burden on the small cell base station <NUM> in terms of electric power. Furthermore, transmitting and receiving a DRS using all the CCs included in the broad frequency band of the milli-wave zone may also cause an increase in inter-cell interference as well as an increase in power consumption.

Hence, the present embodiment provides a mechanism in which the small cell base station <NUM> can transmit a DRS in some of a plurality of CCs in an off state.

Here, it is assumed that in the milli-wave zone, a bandwidth of a CC, which is set at <NUM> in LTE Release <NUM>, can be changed to wider bandwidths such as <NUM>, <NUM>, or <NUM>, for example. In the case where such enlargement of bandwidth is carried out, a mechanism in which a DRS can be transmitted in some of CCs and measured can be said to be effective for a reduction in burden in terms of electric power.

It is assumed that there are a plurality of types of bandwidths of CCs. As examples, a CC with a bandwidth of <NUM>, a CC with a bandwidth of <NUM>, and a CC with a bandwidth of <NUM> are assumed. In addition, it is assumed to be possible to select, for each terminal apparatus, whether to use a bandwidth of <NUM> as one CC with a bandwidth of <NUM>, as two CCs with a bandwidth of <NUM>, or as four CCs with a bandwidth of <NUM>. For example, in the case where a terminal apparatus has only ability to handle a bandwidth of <NUM>, it is desirable that a CC with a bandwidth of <NUM> be brought into an on state. Therefore, the terminal apparatus only needs to perform measurement regarding a CC with a bandwidth of <NUM>, and measurement regarding a CC with a bandwidth of <NUM>, for example, is unnecessary. Since a CC with a bandwidth for which such measurement is to be performed may differ for each terminal apparatus, it is inefficient to transmit a DRS in CCs with the same bandwidth in common for all terminal apparatuses.

Hence, the present embodiment provides a mechanism in which a terminal apparatus can request a CC in which a base station transmits a DRS.

Measuring a DRS in all the CCs included in the broad frequency band imposes a large burden in terms of electric power on not only the base station but also the terminal apparatus side. Particularly in the case where a base station transmits a DRS in some of CCs as described in the first embodiment, measuring the DRS in all the CCs on the terminal apparatus side causes waste in terms of power consumption.

In regard to this point, under present circumstances, with which cycle a DRS is transmitted for each CC is reported to the terminal apparatus side preliminarily by RRC signaling. However, under a situation in which whether or not a DRS is transmitted may be switched frequently for each CC, reporting to the terminal apparatus cannot be said to be sufficient.

Hence, the present embodiment provides a mechanism in which information regarding a DRS can be dynamically reported to a terminal apparatus.

The small cell base station <NUM> (e.g., the transmission processing unit <NUM>) selects a CC in an off state to be used for transmission of a DRS to enable measurement in one or more CCs in an off state, from among a plurality of CCs that may be brought into an on state for uplink transmission or downlink transmission in a small cell. Thus, the small cell base station <NUM> can transmit the DRS selectively in a partial band of the broad milli-wave zone, which enables a reduction in power consumption and also a reduction in inter-cell interference. The small cell base station <NUM> transmits the DRS using the selected CC.

For example, the small cell base station <NUM> (e.g., the transmission processing unit <NUM>) may increase CCs used for transmission of the DRS in a stepwise manner. Conversely, the small cell base station <NUM> may reduce CCs used for transmission of the DRS in a stepwise manner. This makes it possible to provide the DRS in just enough number of CCs, in accordance with an increase tendency or a decrease tendency of the number of users in a cell, for example. As another example, the small cell base station <NUM> may use all the CCs that can be brought into an on state for transmission of the DRS in a stroke.

Here, selection of a CC for providing the DRS is specifically described with reference to <FIG> illustrating an example of a configuration of CCs. The CCs illustrated in <FIG> are CCs that can be brought into an on state, and are CCs that may be used for transmission of the DRS. CC1 to CC4 are CCs with a bandwidth of <NUM>. CC5 and CC6 are CCs with a bandwidth of <NUM>. CC7 is a CC with a bandwidth of <NUM>. For example, in the case where all the CCs are in an off state, the small cell base station <NUM> provides the DRS in CC1. Then, in the case where CC1 is turned on, the small cell base station <NUM> provides the DRS in CC2. Then, in the case where CC2 is turned on, the small cell base station <NUM> provides the DRS in CC3. Then, in the case where CC3 is turned on, the small cell base station <NUM> provides the DRS in CC4. As a matter of course, the small cell base station <NUM> may provide the DRS in CC5 to CC7, or may provide the DRS in a plurality of CCs. In addition, in the case where there is a change in a CC for providing the DRS, the small cell base station <NUM> reports the change to the terminal apparatus <NUM>. This point will be described in detail later.

In addition, the small cell base station <NUM> (e.g., the transmission processing unit <NUM>) may select a CC to be used for transmission of the DRS, on the basis of a measurement result of the DRS in the terminal apparatus <NUM> that connects to the small cell. This makes it possible to provide the DRS in a CC corresponding to fluctuation of radio-wave environment, for example.

The terminal apparatus <NUM> (e.g., the measurement processing unit <NUM>) performs measurement regarding the DRS that has been transmitted using a CC selected from one or more CCs in an off state, among a plurality of CCs that may be brought into an on state for uplink transmission or downlink transmission in the small cell. Thus, the terminal apparatus <NUM> can perform measurement in a partial band of the broad milli-wave zone, which enables a reduction in power consumption. In addition, the terminal apparatus <NUM> reports a measurement report to the small cell base station <NUM>. The small cell base station <NUM> can select a CC in an off state to be used for transmission of the DRS on the basis of this measurement report.

Here, a CC in the present embodiment is assumed to be a CC in the milli-wave zone, which is a frequency band of <NUM> or more.

The small cell base station <NUM> (e.g., the reporting unit <NUM>) reports information indicating a CC that can be brought into an on state, to the terminal apparatus <NUM> that connects to the small cell. Thus, the terminal apparatus <NUM> can find at least a CC in which the DRS may be transmitted, which makes it possible to avoid measurement in a frequency band with no possibility of transmission of the DRS. Information indicating a CC that can be brought into an on state is also referred to as CC configuration information below.

A CC that can be brought into an on state may be associated with a CC used for transmission of the DRS. For example, this association may be a combination of a CC used for transmission of the DRS and a CC that may be brought into an on state on the basis of a measurement report of the DRS provided in the CC. Moreover, this association may be a bidirectional relationship. For example, in the case where CC configuration information includes information indicating CC1 to CC7 illustrated in <FIG>, CC2 may be brought into an on state on the basis of a measurement report of CC1, or CC1 may be brought into an on state on the basis of a measurement report of CC2. As a matter of course, at least one of CC2 to CC7 may be brought into an on state on the basis of the measurement report of CC1. As will be described later, the terminal apparatus <NUM> may request a CC in which provision of the DRS is to be started. In the case where CC configuration information including the above association is reported from the small cell base station <NUM>, the terminal apparatus <NUM> can request a start of provision of the DRS in a desired CC among CCs that may be brought into an on state depending on the contents of a measurement report.

A CC that can be brought into an on state may include a band different from that of an associated CC used for transmission of the DRS. That is, a CC subjected to measurement does not need to coincide with a CC brought into an on state. For example, in the example illustrated in <FIG>, CC6 may be brought into an on state on the basis of a measurement result of CC1.

For reporting of CC configuration information, for example, means such as system information (SI), RRC signaling or a physical downlink control channel (PDCCH) may be used. Moreover, reporting of CC configuration information may be performed periodically, or may be performed at any timing (e.g., whenever there is a change). Note that CC configuration information may be static or quasi-static information.

The small cell base station <NUM> (e.g., the reporting unit <NUM>) reports information regarding arrangement of the DRS in each CC, to the terminal apparatus <NUM> that connects to the small cell. Here, arrangement of the DRS refers to a transmission cycle, a frequency in each CC, and the like. Reporting of this information enables the terminal apparatus <NUM> to perform measurement appropriately. This information is also referred to as DRS arrangement information below.

For reporting of DRS arrangement information, for example, means such as SI, RRC signaling or a PDCCH may be used. Moreover, reporting of DRS arrangement information may be performed periodically, or may be performed at any timing (e.g., whenever there is a change). Note that DRS arrangement information may be static or quasi-static information.

The small cell base station <NUM> (e.g., the reporting unit <NUM>) reports information indicating a CC to be used for transmission of the DRS, to the terminal apparatus <NUM> that connects to the small cell. Reporting of this information enables the terminal apparatus <NUM> to perform measurement on a CC actually used for transmission of the DRS, among CCs included in the broad frequency band. This information is also referred to as DRS state information below.

Here, <FIG> illustrate examples of DRS state information. In <FIG>, a value of a bit position corresponding to each of CC1 to CC7 illustrated in <FIG> indicates whether each CC is used for transmission of the DRS. The first bit corresponds to CC1, the second bit corresponds to CC2, the third bit corresponds to CC3, the fourth bit corresponds to CC4, the fifth bit corresponds to CC5, the sixth bit corresponds to CC6, and the seventh bit corresponds to CC7. The bit value <NUM> indicates that the CC is not used for transmission of the DRS, and the bit value <NUM> indicates that the CC is used for transmission of the DRS. In <FIG>, a value of a bit position corresponding to each of CC1 to CC4 illustrated in <FIG> indicates whether each CC is used for transmission of the DRS. Information expression in such a form is effective in the case where the DRS is transmitted in a CC with a width of <NUM>. In this case, four <NUM>-MHz DRSs may be used in a bundle in place of a DRS for <NUM>.

In addition, the small cell base station <NUM> may report information indicating a CC of which use in transmission of the DRS is to be started or stopped. That is, in the case where there is a change in a CC to be used for transmission of the DRS, the small cell base station <NUM> may report information indicating the difference.

Moreover, the small cell base station <NUM> may report DRS state information in the case where there is a change in a CC to be used for transmission of the DRS. That is, the small cell base station <NUM> may report DRS state information at timing of a change in a CC to be used for transmission of the DRS. This enables the terminal apparatus <NUM> to perform measurement on an appropriate CC, even in the case where there is a change in a CC to be used for transmission of the DRS, and enables a reduction in power consumption. As a matter of course, reporting of DRS arrangement information may be performed periodically. The cycle may be approximately <NUM>, for example.

For reporting of DRS state information, for example, means such as SI, RRC signaling or a PDCCH may be used. However, it is desirable to use means capable of instantaneous reporting, such as a PDCCH or SI, for example, for reporting of DRS state information. This enables the terminal apparatus <NUM> to switch a measurement-target CC instantaneously even under a situation in which a CC in which the DRS is transmitted is switched frequently.

The terminal apparatus <NUM> (e.g., the requesting unit <NUM>) may request a change of a CC to be used for transmission of the DRS. For example, the terminal apparatus <NUM> may report information indicating a CC in an off state to be requested to be used for transmission of the DRS, to the small cell base station <NUM>. That is, the terminal apparatus <NUM> may request a start of provision of the DRS. Then, the small cell base station <NUM> (e.g., a DRS transmission processing unit <NUM>) may select a CC to be used for transmission of the DRS on the basis of the request from the terminal apparatus <NUM> that connects to the small cell. This enables provision of the DRS to be started quickly in a CC in which the terminal apparatus <NUM> desires to perform measurement. Similarly, the terminal apparatus <NUM> can also request a stop of provision of the DRS, in which case unnecessary provision of the DRS can be stopped quickly. Such a request is also referred to as a DRS request below.

The terminal apparatus <NUM> may designate a CC related to a DRS request on the basis of CC configuration information. For example, the terminal apparatus <NUM> designates a CC in which provision of the DRS is to be requested to be started or stopped, from among a CC in which measurement has been performed and one or more CCs associated in the CC configuration information. For example, in the case where CC configuration information includes information indicating CC1 to CC7 illustrated in <FIG>, the terminal apparatus <NUM> may request transmission of the DRS in at least one of CC2 to CC7 in the case where measurement has been performed in CC1.

This DRS request may be reported together with a measurement report, for example. In that case, the small cell base station <NUM> can select whether or not to start provision of the DRS on the basis of both the measurement report and the DRS request. Note that being reported together may mean concurrent reporting, may mean serial reporting, or may mean being reported included in the same signal or different signals.

The small cell base station <NUM> (e.g., the transmission processing unit <NUM>) selects a CC to be brought into an on state or brought into an off state. For example, the small cell base station <NUM> may make a selection on the basis of a measurement result from the terminal apparatus <NUM> that connects to the small cell. This makes it possible to appropriately turn on/off a CC in accordance with fluctuation of radio-wave environment, for example.

<FIG> is a sequence diagram illustrating an example of the flow of a process of a DRS request procedure executed in the system <NUM> according to the present embodiment. As illustrated in <FIG>, this sequence involves the small cell base station <NUM> and the terminal apparatus <NUM>.

First, the small cell base station <NUM> transmits setting information to the terminal apparatus <NUM> (step S102). This setting information includes CC configuration information, DRS arrangement information, and DRS state information. CC configuration information includes information indicating a CC used for transmission of the DRS and information being associated with the CC and indicating a CC that can be brought into an on state.

Then, the small cell base station <NUM> transmits the DRS in accordance with the setting information (step S104). Specifically, the small cell base station <NUM> transmits the DRS in a CC to be used for transmission of the DRS that is indicated by the DRS state information, among CCs indicated by the CC configuration information, with an arrangement indicated by the DRS arrangement information.

Next, the terminal apparatus <NUM> performs measurement of the DRS on the basis of the received setting information (step S106), and transmits a DRS request together with a measurement report to the small cell base station <NUM> (step S108). Note that the measurement report and the DRS request may be transmitted as different messages. Next, the small cell base station <NUM> selects a CC to be used for transmission of the DRS on the basis of the received measurement report and DRS request (step S110), and transmits DRS state information to the terminal apparatus <NUM> in accordance with a selection result (step S112). Then, the small cell base station <NUM> transmits the DRS in a CC of which use has been reported by the DRS state information (i.e., the CC selected in step S110) (step S114).

Then, the terminal apparatus <NUM> performs measurement on the basis of the received DRS state information (step S116), and transmits a measurement report to the small cell base station <NUM> (step S118). Then, the small cell base station <NUM> determines on/off of a CC on the basis of the measurement report (step S120).

After the above steps, the process ends.

In the first embodiment, a CC is brought into an on state on the basis of determination on the base station side. Therefore, there is a case where CCs are brought into an on state in a stepwise manner up to a width of <NUM>; for a terminal apparatus requiring immediate use of a CC with a width of <NUM>, for example, a long time lag occurs until the requirement is satisfied. Such a time lag may cause a decrease in throughput, or deterioration of Quality of Service (QoS) of a service requiring low delay.

Hence, the present embodiment provides a mechanism in which a terminal apparatus can request a CC to be brought into an on state by a base station.

The terminal apparatus <NUM> (e.g., the requesting unit <NUM>) may request a state change of a CC. For example, the terminal apparatus <NUM> may report information indicating a CC to be requested to be brought into an on state to the small cell base station <NUM>. That is, the terminal apparatus <NUM> may request turning on of a CC. Then, the small cell base station <NUM> (e.g., the DRS transmission processing unit <NUM>) may select a CC to be brought into an on state on the basis of the request from the terminal apparatus <NUM> that connects to the small cell. This makes it possible to shorten a time lag until a CC that the terminal apparatus <NUM> desires to be brought into an on state (typically, a CC desired to be activated after being turned on) is actually brought into an on state. Similarly, the terminal apparatus <NUM> can also request bringing a CC into an off state, in which case a time lag until a desired CC is actually brought into an off state can be shortened. Such a request is also referred to as a CC state change request below.

The terminal apparatus <NUM> may designate a CC related to a CC state change request on the basis of CC configuration information. For example, the terminal apparatus <NUM> designates a CC to be requested to be brought into an on state, from among a CC in which measurement has been performed and one or more CCs associated in the CC configuration information. For example, in the case where CC configuration information includes information indicating CC1 to CC7 illustrated in <FIG>, the terminal apparatus <NUM> may request bringing at least one of CC1 to CC7 into an on state in the case where measurement has been performed in CC1.

This CC state change request may be reported together with a measurement report, for example. In that case, the small cell base station <NUM> can determine on/off of a CC on the basis of both the measurement report and the CC state change request. Note that being reported together may mean concurrent reporting, may mean serial reporting, or may mean being reported included in the same signal or different signals.

The small cell base station <NUM> (e.g., the transmission processing unit <NUM>) controls a transmission cycle of the DRS. For example, the small cell base station <NUM> may make a transmission cycle of the DRS differ for each CC. In regard to a time lag between occurrence of a state change request and satisfaction of the request, in the case where an allowable length of the time lag differs depending on the CC, it is effective to make the transmission cycle differ. In particular, the small cell base station <NUM> may make a transmission cycle of the DRS shorter for CCs with smaller bandwidths. This can make a time lag shorter for CCs with smaller bandwidths. This is because CCs with smaller bandwidths are required to be used in a higher degree in terms of a reduction in power consumption both in the small cell base station <NUM> and in the terminal apparatus <NUM>, and are presumed to desire a shorter time lag.

<FIG> illustrates such an example in which a transmission cycle of the DRS is made shorter for CCs with smaller bandwidths. In the example illustrated in <FIG>, a DRS for a bandwidth of <NUM>, a DRS for a bandwidth of <NUM>, and a DRS for a bandwidth of <NUM> are each transmitted in one CC with the corresponding bandwidth. In addition, the shortest transmission cycle is set in CC1, the longest transmission cycle is set in CC7, and a transmission cycle with a length between those in CC1 and CC7 is set in CC5.

<FIG> is a sequence diagram illustrating an example of the flow of a process of a CC state change request procedure executed in the system <NUM> according to the present embodiment. As illustrated in <FIG>, this sequence involves the small cell base station <NUM> and the terminal apparatus <NUM>.

First, the small cell base station <NUM> transmits setting information to the terminal apparatus <NUM> (step S202), and transmits the DRS in accordance with the setting information (step S204).

Then, the terminal apparatus <NUM> performs measurement of the DRS on the basis of the received setting information (step S206), and transmits a CC state change request together with a measurement report to the small cell base station <NUM> (step S208). Note that the measurement report and the CC state change request may be transmitted as different messages. Next, the small cell base station <NUM> determines on/off of a CC on the basis of the received measurement report and CC state change request (step S210).

The technology according to the present disclosure is applicable to various products. The small cell base station <NUM> may also be implemented, for example, as any type of evolved Node B (eNB) such as macro eNBs and small eNBs. Small eNBs may be eNBs that cover smaller cells than the macrocells, such as pico eNBs, micro eNBs, or home (femto) eNBs. Instead, the small cell base station <NUM> may be implemented as another type of base station such as Nodes B or base transceiver stations (BTSs). The small cell base station <NUM> may include the main apparatus (which is also referred to as base station apparatus) that controls wireless communication and one or more remote radio heads (RRHs) that are disposed at different locations from that of the main apparatus. Also, various types of terminals described below may function as the small cell base station <NUM> by temporarily or semi-permanently executing the functionality of the base station. Furthermore, at least some of structural elements of the small cell base station <NUM> may be realized in a base station apparatus or a module for a base station apparatus.

Further, the terminal apparatus <NUM> may be implemented, for example, as a mobile terminal such as smartphones, tablet personal computers (PCs), notebook PCs, portable game terminals, portable/dongle mobile routers, and digital cameras, or an in-vehicle terminal such as car navigation apparatuses. Further, the terminal apparatus <NUM> may be implemented as a machine type communication (MTC) terminal for establishing a machine to machine (M2M) communication. Furthermore, at least some of structural elements of the terminal apparatus <NUM> may be implemented as a module (e.g., integrated circuit module including a single die) that is mounted on these terminals.

<FIG> is a block diagram illustrating a first example of a schematic configuration of an eNB to which the technology according to the present disclosure may be applied. An eNB <NUM> includes one or more antennas <NUM> and a base station apparatus <NUM>. Each antenna <NUM> and the base station apparatus <NUM> may be connected to each other via an RF cable.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (e.g., a plurality of antenna elements constituting a MIMO antenna) and is used for the base station apparatus <NUM> to transmit and receive a wireless signal. The eNB <NUM> may include the plurality of the antennas <NUM> as illustrated in <FIG>, and the plurality of antennas <NUM> may, for example, correspond to a plurality of frequency bands used by the eNB <NUM>. It should be noted that while <FIG> illustrates an example in which the eNB <NUM> includes the plurality of antennas <NUM>, the eNB <NUM> may include the single antenna <NUM>.

The base station apparatus <NUM> includes a controller <NUM>, a memory <NUM>, a network interface <NUM>, and a wireless communication interface <NUM>.

The controller <NUM> may be, for example, a CPU or a DSP, and operates various functions of an upper layer of the base station apparatus <NUM>. For example, the controller <NUM> generates a data packet from data in a signal processed by the wireless communication interface <NUM>, and transfers the generated packet via the network interface <NUM>. The controller <NUM> may generate a bundled packet by bundling data from a plurality of base band processors to transfer the generated bundled packet. Further, the controller <NUM> may also have a logical function of performing control such as radio resource control, radio bearer control, mobility management, admission control, and scheduling. Further, the control may be performed in cooperation with a surrounding eNB or a core network node. The memory <NUM> includes a RAM and a ROM, and stores a program executed by the controller <NUM> and a variety of control data (such as, for example, terminal list, transmission power data, and scheduling data).

The network interface <NUM> is a communication interface for connecting the base station apparatus <NUM> to the core network <NUM>. The controller <NUM> may communicate with a core network node or another eNB via the network interface <NUM>. In this case, the eNB <NUM> may be connected to a core network node or another eNB through a logical interface (e.g., S1 interface or X2 interface). The network interface <NUM> may be a wired communication interface or a wireless communication interface for wireless backhaul. In the case where the network interface <NUM> is a wireless communication interface, the network interface <NUM> may use a higher frequency band for wireless communication than a frequency band used by the wireless communication interface <NUM>.

The wireless communication interface <NUM> supports a cellular communication system such as long term evolution (LTE) or LTE-Advanced, and provides wireless connection to a terminal located within the cell of the eNB <NUM> via the antenna <NUM>. The wireless communication interface <NUM> may typically include a base band (BB) processor <NUM>, an RF circuit <NUM>, and the like. The BB processor <NUM> may, for example, perform encoding/decoding, modulation/demodulation, multiplexing/demultiplexing, and the like, and performs a variety of signal processing on each layer (e.g., L1, medium access control (MAC), radio link control (RLC), and packet data convergence protocol (PDCP)). The BB processor <NUM> may have part or all of the logical functions as described above instead of the controller <NUM>. The BB processor <NUM> may be a module including a memory having a communication control program stored therein, a processor to execute the program, and a related circuit, and the function of the BB processor <NUM> may be changeable by updating the program. Further, the module may be a card or blade to be inserted into a slot of the base station apparatus <NUM>, or a chip mounted on the card or the blade. Meanwhile, the RF circuit <NUM> may include a mixer, a filter, an amplifier, and the like, and transmits and receives a wireless signal via the antenna <NUM>.

The wireless communication interface <NUM> may include a plurality of the BB processors <NUM> as illustrated in <FIG>, and the plurality of BB processors <NUM> may, for example, correspond to a plurality of frequency bands used by the eNB <NUM>. Further, the wireless communication interface <NUM> may also include a plurality of the RF circuits <NUM>, as illustrated in <FIG>, and the plurality of RF circuits <NUM> may, for example, correspond to a plurality of antenna elements. Note that <FIG> illustrates an example in which the wireless communication interface <NUM> includes the plurality of BB processors <NUM> and the plurality of RF circuits <NUM>, but the wireless communication interface <NUM> may include the single BB processor <NUM> or the single RF circuit <NUM>.

In the eNB <NUM> illustrated in <FIG>, one or more structural elements included in the small cell base station <NUM> (the transmission processing unit <NUM> and/or the reporting unit <NUM>) described with reference to <FIG> may be implemented by the wireless communication interface <NUM>. Alternatively, at least some of these structural elements may be implemented by the controller <NUM>. As an example, a module which includes a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the controller <NUM> may be mounted in the eNB <NUM>, and the one or more structural elements may be implemented by the module. In this case, the module may store a program for causing the processor to function as the one or more structural elements (i.e., a program for causing the processor to execute operations of the one or more structural elements) and may execute the program. As another example, the program for causing the processor to function as the one or more structural elements may be installed in the eNB <NUM>, and the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the controller <NUM> may execute the program. As described above, the eNB <NUM>, the base station apparatus <NUM>, or the module may be provided as an apparatus which includes the one or more structural elements, and the program for causing the processor to function as the one or more structural elements may be provided. In addition, a readable recording medium in which the program is recorded may be provided.

In addition, in the eNB <NUM> illustrated in <FIG>, the wireless communication unit <NUM> described with reference to <FIG> may be implemented by the wireless communication interface <NUM> (for example, the RF circuit <NUM>). Moreover, the antenna unit <NUM> may be implemented by the antenna <NUM>. In addition, the network communication unit <NUM> may be implemented by the controller <NUM> and/or the network interface <NUM>. Further, the storage unit <NUM> may be implemented by the memory <NUM>.

<FIG> is a block diagram illustrating a second example of a schematic configuration of an eNB to which the technology according to the present disclosure may be applied. An eNB <NUM> includes one or more antennas <NUM>, a base station apparatus <NUM>, and an RRH <NUM>. Each of the antennas <NUM> and the RRH <NUM> may be connected to each other via an RF cable. Further, the base station apparatus <NUM> and the RRH <NUM> may be connected to each other by a high speed line such as optical fiber cables.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (e.g., antenna elements constituting a MIMO antenna), and is used for the RRH <NUM> to transmit and receive a wireless signal. The eNB <NUM> may include a plurality of the antennas <NUM> as illustrated in <FIG>, and the plurality of antennas <NUM> may, for example, correspond to a plurality of frequency bands used by the eNB <NUM>. Note that <FIG> illustrates an example in which the eNB <NUM> includes the plurality of antennas <NUM>, but the eNB <NUM> may include the single antenna <NUM>.

The base station apparatus <NUM> includes a controller <NUM>, a memory <NUM>, a network interface <NUM>, a wireless communication interface <NUM>, and a connection interface <NUM>. The controller <NUM>, the memory <NUM>, and the network interface <NUM> are similar to the controller <NUM>, the memory <NUM>, and the network interface <NUM> described with reference to <FIG>.

The wireless communication interface <NUM> supports a cellular communication system such as LTE and LTE-Advanced, and provides wireless connection to a terminal located in a sector corresponding to the RRH <NUM> via the RRH <NUM> and the antenna <NUM>. The wireless communication interface <NUM> may typically include a BB processor <NUM> or the like. The BB processor <NUM> is similar to the BB processor <NUM> described with reference to <FIG> except that the BB processor <NUM> is connected to an RF circuit <NUM> of the RRH <NUM> via the connection interface <NUM>. The wireless communication interface <NUM> may include a plurality of the BB processors <NUM>, as illustrated in <FIG>, and the plurality of BB processors <NUM> may, for example, correspond to a plurality of frequency bands used by the eNB <NUM>. Note that <FIG> illustrates an example in which the wireless communication interface <NUM> includes the plurality of BB processors <NUM>, but the wireless communication interface <NUM> may include the single BB processor <NUM>.

The connection interface <NUM> is an interface for connecting the base station apparatus <NUM> (wireless communication interface <NUM>) to the RRH <NUM>. The connection interface <NUM> may be a communication module for communication on the high speed line which connects the base station apparatus <NUM> (wireless communication interface <NUM>) to the RRH <NUM>.

Further, the RRH <NUM> includes a connection interface <NUM> and a wireless communication interface <NUM>.

The connection interface <NUM> is an interface for connecting the RRH <NUM> (wireless communication interface <NUM>) to the base station apparatus <NUM>. The connection interface <NUM> may be a communication module for communication on the high speed line.

The wireless communication interface <NUM> transmits and receives a wireless signal via the antenna <NUM>. The wireless communication interface <NUM> may typically include the RF circuit <NUM> or the like. The RF circuit <NUM> may include a mixer, a filter, an amplifier and the like, and transmits and receives a wireless signal via the antenna <NUM>. The wireless communication interface <NUM> may include a plurality of the RF circuits <NUM> as illustrated in <FIG>, and the plurality of RF circuits <NUM> may, for example, correspond to a plurality of antenna elements. Note that <FIG> illustrates an example in which the wireless communication interface <NUM> includes the plurality of RF circuits <NUM>, but the wireless communication interface <NUM> may include the single RF circuit <NUM>.

In the eNB <NUM> illustrated in <FIG>, one or more structural elements included in the small cell base station <NUM> (the transmission processing unit <NUM> and/or the reporting unit <NUM>) described with reference to <FIG> may be implemented by the wireless communication interface <NUM> and/or the wireless communication interface <NUM>. Alternatively, at least some of these structural elements may be implemented by the controller <NUM>. As an example, a module which includes a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the controller <NUM> may be mounted in the eNB <NUM>, and the one or more structural elements may be implemented by the module. In this case, the module may store a program for causing the processor to function as the one or more structural elements (i.e., a program for causing the processor to execute operations of the one or more structural elements) and may execute the program. As another example, the program for causing the processor to function as the one or more structural elements may be installed in the eNB <NUM>, and the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the controller <NUM> may execute the program. As described above, the eNB <NUM>, the base station apparatus <NUM>, or the module may be provided as an apparatus which includes the one or more structural elements, and the program for causing the processor to function as the one or more structural elements may be provided. In addition, a readable recording medium in which the program is recorded may be provided.

In addition, in the eNB <NUM> illustrated in <FIG>, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented by the wireless communication interface <NUM> (for example, the RF circuit <NUM>). Moreover, the antenna unit <NUM> may be implemented by the antenna <NUM>. In addition, the network communication unit <NUM> may be implemented by the controller <NUM> and/or the network interface <NUM>. Further, the storage unit <NUM> may be implemented by the memory <NUM>.

<FIG> is a block diagram illustrating an example of a schematic configuration of a smartphone <NUM> to which the technology according to the present disclosure may be applied. The smartphone <NUM> includes a processor <NUM>, a memory <NUM>, a storage <NUM>, an external connection interface <NUM>, a camera <NUM>, a sensor <NUM>, a microphone <NUM>, an input device <NUM>, a display device <NUM>, a speaker <NUM>, a wireless communication interface <NUM>, one or more antenna switches <NUM>, one or more antennas <NUM>, a bus <NUM>, a battery <NUM>, and an auxiliary controller <NUM>.

The processor <NUM> may be, for example, a CPU or a system on chip (SoC), and controls the functions of an application layer and other layers of the smartphone <NUM>. The memory <NUM> includes a RAM and a ROM, and stores a program executed by the processor <NUM> and data. The storage <NUM> may include a storage medium such as semiconductor memories and hard disks. The external connection interface <NUM> is an interface for connecting the smartphone <NUM> to an externally attached device such as memory cards and universal serial bus (USB) devices.

The camera <NUM> includes, for example, an image sensor such as charge coupled devices (CCDs) and complementary metal oxide semiconductor (CMOS), and generates a captured image. The sensor <NUM> may include a sensor group including, for example, a positioning sensor, a gyro sensor, a geomagnetic sensor, an acceleration sensor and the like. The microphone <NUM> converts a sound that is input into the smartphone <NUM> to an audio signal. The input device <NUM> includes, for example, a touch sensor which detects that a screen of the display device <NUM> is touched, a key pad, a keyboard, a button, a switch or the like, and accepts an operation or an information input from a user. The display device <NUM> includes a screen such as liquid crystal displays (LCDs) and organic light emitting diode (OLED) displays, and displays an output image of the smartphone <NUM>. The speaker <NUM> converts the audio signal that is output from the smartphone <NUM> to a sound.

The wireless communication interface <NUM> supports a cellular communication system such as LTE or LTE-Advanced, and performs wireless communication. The wireless communication interface <NUM> may typically include the BB processor <NUM>, the RF circuit <NUM>, and the like. The BB processor <NUM> may, for example, perform encoding/decoding, modulation/demodulation, multiplexing/demultiplexing, and the like, and performs a variety of types of signal processing for wireless communication. On the other hand, the RF circuit <NUM> may include a mixer, a filter, an amplifier, and the like, and transmits and receives a wireless signal via the antenna <NUM>. The wireless communication interface <NUM> may be a one-chip module in which the BB processor <NUM> and the RF circuit <NUM> are integrated. The wireless communication interface <NUM> may include a plurality of BB processors <NUM> and a plurality of RF circuits <NUM> as illustrated in <FIG>. Note that <FIG> illustrates an example in which the wireless communication interface <NUM> includes a plurality of BB processors <NUM> and a plurality of RF circuits <NUM>, but the wireless communication interface <NUM> may include a single BB processor <NUM> or a single RF circuit <NUM>.

Further, the wireless communication interface <NUM> may support other types of wireless communication system such as a short range wireless communication system, a near field communication system, and a wireless local area network (LAN) system in addition to the cellular communication system, and in this case, the wireless communication interface <NUM> may include the BB processor <NUM> and the RF circuit <NUM> for each wireless communication system.

Each antenna switch <NUM> switches a connection destination of the antenna <NUM> among a plurality of circuits (for example, circuits for different wireless communication systems) included in the wireless communication interface <NUM>.

Each of the antennas <NUM> includes one or more antenna elements (for example, a plurality of antenna elements constituting a MIMO antenna) and is used for transmission and reception of the wireless signal by the wireless communication interface <NUM>. The smartphone <NUM> may include a plurality of antennas <NUM> as illustrated in <FIG>. Note that <FIG> illustrates an example in which the smartphone <NUM> includes a plurality of antennas <NUM>, but the smartphone <NUM> may include a single antenna <NUM>.

Further, the smartphone <NUM> may include the antenna <NUM> for each wireless communication system. In this case, the antenna switch <NUM> may be omitted from a configuration of the smartphone <NUM>.

The bus <NUM> connects the processor <NUM>, the memory <NUM>, the storage <NUM>, the external connection interface <NUM>, the camera <NUM>, the sensor <NUM>, the microphone <NUM>, the input device <NUM>, the display device <NUM>, the speaker <NUM>, the wireless communication interface <NUM>, and the auxiliary controller <NUM> to each other. The battery <NUM> supplies electric power to each block of the smartphone <NUM> illustrated in <FIG> via a feeder line that is partially illustrated in the figure as a dashed line. The auxiliary controller <NUM>, for example, operates a minimally necessary function of the smartphone <NUM> in a sleep mode.

In the smartphone <NUM> illustrated in <FIG>, one or more structural elements included in the terminal apparatus <NUM> (the measurement processing unit <NUM> and/or the requesting unit <NUM>) described with reference to <FIG> may be implemented by the wireless communication interface <NUM>. Alternatively, at least some of these structural elements may be implemented by the processor <NUM> or the auxiliary controller <NUM>. As an example, a module which includes a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM>, the processor <NUM>, and/or the auxiliary controller <NUM> may be mounted in the smartphone <NUM>, and the one or more structural elements may be implemented by the module. In this case, the module may store a program for causing the processor to function as the one or more structural elements (i.e., a program for causing the processor to execute operations of the one or more structural elements) and may execute the program. As another example, the program for causing the processor to function as the one or more structural elements may be installed in the smartphone <NUM>, and the wireless communication interface <NUM> (for example, the BB processor <NUM>), the processor <NUM>, and/or the auxiliary controller <NUM> may execute the program. As described above, the smartphone <NUM> or the module may be provided as an apparatus which includes the one or more structural elements, and the program for causing the processor to function as the one or more structural elements may be provided. In addition, a readable recording medium in which the program is recorded may be provided.

In addition, in the smartphone <NUM> illustrated in <FIG>, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented by the wireless communication interface <NUM> (for example, the RF circuit <NUM>). Moreover, the antenna unit <NUM> may be implemented by the antenna <NUM>. Further, the storage unit <NUM> may be implemented by the memory <NUM>.

<FIG> is a block diagram illustrating an example of a schematic configuration of a car navigation apparatus <NUM> to which the technology according to the present disclosure may be applied. The car navigation apparatus <NUM> includes a processor <NUM>, a memory <NUM>, a global positioning system (GPS) module <NUM>, a sensor <NUM>, a data interface <NUM>, a content player <NUM>, a storage medium interface <NUM>, an input device <NUM>, a display device <NUM>, a speaker <NUM>, a wireless communication interface <NUM>, one or more antenna switches <NUM>, one or more antennas <NUM>, and a battery <NUM>.

The processor <NUM> may be, for example, a CPU or an SoC, and controls the navigation function and the other functions of the car navigation apparatus <NUM>. The memory <NUM> includes a RAM and a ROM, and stores a program executed by the processor <NUM> and data.

The GPS module <NUM> uses a GPS signal received from a GPS satellite to measure the position (e.g., latitude, longitude, and altitude) of the car navigation apparatus <NUM>. The sensor <NUM> may include a sensor group including, for example, a gyro sensor, a geomagnetic sensor, a barometric sensor and the like. The data interface <NUM> is, for example, connected to an in-vehicle network <NUM> via a terminal that is not illustrated, and acquires data such as vehicle speed data generated on the vehicle side.

The content player <NUM> reproduces content stored in a storage medium (e.g., CD or DVD) inserted into the storage medium interface <NUM>. The input device <NUM> includes, for example, a touch sensor which detects that a screen of the display device <NUM> is touched, a button, a switch or the like, and accepts operation or information input from a user. The display device <NUM> includes a screen such as LCDs and OLED displays, and displays an image of the navigation function or the reproduced content. The speaker <NUM> outputs a sound of the navigation function or the reproduced content.

Further, the wireless communication interface <NUM> may support other types of wireless communication system such as a short range wireless communication system, a near field communication system, and a wireless LAN system in addition to the cellular communication system, and in this case, the wireless communication interface <NUM> may include the BB processor <NUM> and the RF circuit <NUM> for each wireless communication system.

Each of the antennas <NUM> includes one or more antenna elements (for example, a plurality of antenna elements constituting a MIMO antenna) and is used for transmission and reception of the wireless signal by the wireless communication interface <NUM>. The car navigation apparatus <NUM> may include a plurality of antennas <NUM> as illustrated in <FIG>. Note that <FIG> illustrates an example in which the car navigation apparatus <NUM> includes a plurality of antennas <NUM>, but the car navigation apparatus <NUM> may include a single antenna <NUM>.

Further, the car navigation apparatus <NUM> may include the antenna <NUM> for each wireless communication system. In this case, the antenna switch <NUM> may be omitted from a configuration of the car navigation apparatus <NUM>.

The battery <NUM> supplies electric power to each block of the car navigation apparatus <NUM> illustrated in <FIG> via a feeder line that is partially illustrated in the figure as a dashed line. Further, the battery <NUM> accumulates the electric power supplied from the vehicle.

In the car navigation apparatus <NUM> illustrated in <FIG>, one or more structural elements included in the terminal apparatus <NUM> (the measurement processing unit <NUM> and/or the requesting unit <NUM>) described with reference to <FIG> may be implemented by the wireless communication interface <NUM>. Alternatively, at least some of these structural elements may be implemented by the processor <NUM>. As an example, a module which includes a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the processor <NUM> may be mounted in the car navigation apparatus <NUM>, and the one or more structural elements may be implemented by the module. In this case, the module may store a program for causing the processor to function as the one or more structural elements (i.e., a program for causing the processor to execute operations of the one or more structural elements) and may execute the program. As another example, the program for causing the processor to function as the one or more structural elements may be installed in the car navigation apparatus <NUM>, and the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the processor <NUM> may execute the program. As described above, the car navigation apparatus <NUM> or the module may be provided as an apparatus which includes the one or more structural elements, and the program for causing the processor to function as the one or more structural elements may be provided. In addition, a readable recording medium in which the program is recorded may be provided.

In addition, in the car navigation apparatus <NUM> illustrated in <FIG>, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented by the wireless communication interface <NUM> (for example, the RF circuit <NUM>). Moreover, the antenna unit <NUM> may be implemented by the antenna <NUM>. Further, the storage unit <NUM> may be implemented by the memory <NUM>.

The technology of the present disclosure may also be realized as an in-vehicle system (or a vehicle) <NUM> including one or more blocks of the car navigation apparatus <NUM>, the in-vehicle network <NUM>, and a vehicle module <NUM>. In other words, the in-vehicle system (or a vehicle) <NUM> may be provided as an apparatus which includes the measurement processing unit <NUM> and the requesting unit <NUM>. The vehicle module <NUM> generates vehicle data such as vehicle speed, engine speed, and trouble information, and outputs the generated data to the in-vehicle network <NUM>.

An embodiment of the present disclosure has been described in detail with reference to <FIG>. As described above, the small cell base station <NUM> according to the present embodiment selects, from among one or more unit frequency bands in an off state in a plurality of unit frequency bands that may be brought into an on state for uplink communication or downlink communication in a small cell, the unit frequency band in an off state to be used for transmission of a discovery signal to enable measurement in the unit frequency band in an off state. Thus, the small cell base station <NUM> can transmit the discovery signal selectively in a partial band of the broad milli-wave zone, which enables a reduction in power consumption and also a reduction in inter-cell interference. This enables the system <NUM> to effectively use a unit frequency band using the milli-wave zone, and can improve traffic accommodation efficiency of the terminal apparatus <NUM> in a cellular network.

Claim 1:
An apparatus (<NUM>) for operating a base station, comprising:
a processing unit (<NUM>) configured to select, from among one or more unit frequency bands in an off state in a plurality of unit frequency bands, a first unit frequency band in an off state, and
a transmission processing unit (<NUM>) configured to transmit a signal for measurement in the selected first unit frequency band to enable measurement in the first unit frequency band in an off state,
wherein the processing unit (<NUM>) is configured to report information indicating the first unit frequency band to a terminal, in a case where there is a change in the first unit frequency band to be used for transmission of the signal for measurement, and
wherein a physical downlink control channel, PDCCH, or system information is used for the reporting.