Patent Description:
In UMTS (Universal Mobile Telecommunications System) networks, for the purpose of improving spectral efficiency and further improving data rates, by adopting HSDPA (High SpeedDownlink Packet Access) and HSUPA (High Speed Uplink Packet Access), it is performed exploiting maximum features of the system based on W-CDMA (Wideband Code Division Multiple Access). For the UMTS network, for the purpose of further increasing high-speed data rates, providing low delay and the like, Long Term Evolution (LTE) has been studied (Non-patent Literature <NUM>).

In the <NUM> system, a fixed band of <NUM> is substantially used, and it is possible to achieve transmission rates of approximately maximum <NUM> Mbps in downlink. Meanwhile, in the LTE system, using variable bands ranging from <NUM> to <NUM>, it is possible to achieve transmission rates of maximum <NUM> Mbps in downlink and about <NUM> Mbps in uplink. Further, in the UMTS network, for the purpose of further increasing the wide-band and high speed, successor systems to LTE have been studied (for example, also called LTE Advanced (LTE-A) or LTE Enhancement).

In such a system, as a duplex scheme applied to radio systems, there are a Frequency Division Duplex (FDD) scheme and Time Division Duplex (TDD) scheme. In the FDD scheme, different frequency bands spaced a sufficient interval are used in uplink and downlink. In the TDD scheme, the same frequency band is used in uplink and downlink, and uplink communications and downlink communications are divided by time. In the FDD scheme, it is necessary to adequately widen the interval between the frequency bands used in uplink and downlink, and therefore, not only the base station apparatus but also the mobile terminal apparatus require a duplexer with high accuracy.

Further, mobile terminal apparatuses (Rel. <NUM> or later) of LTE system and its successor system support also a Half-duplex FDD scheme. In the Half-duplex FDD scheme, as in the FDD scheme, different frequency bands are used in uplink and downlink, while uplink communications and downlink communications are switched by time. Therefore, mobile terminal apparatuses do not need a duplexer with high accuracy, and it is possible to simplify the mobile terminal apparatuses.

Document <CIT> relates to Frequency Division Duplex Orthogonal Frequency Division Multiple Access systems.

Document <CIT> relates to a method and apparatus for reducing co-channel interference.

Document <NPL>. relates to uplink backhaul timing alternatives.

Document <NPL> relates to backhaul UCI Transmission.

Document <NPL> relates to options in support of forward compatibility, and a comparison of MBSFN vs. blank subframes.

Document <NPL> relates to analysis of HD-FDD error and TX/RX conflict scenarios.

Document <NPL> relates to half Duplex FDD in LTE.

Document <CIT> relates to a method for determining, in a wireless cellular telecommunication network, which symbols transferred in a downlink timeslot have to be selected by a half-duplex terminal.

Document <NPL> relates to sub-frame structure for half duplex communication systems in which idle periods have a duration equal to a multiple of the symbol duration.

Document <CIT> relates to method for operating a user agent and access device located within a communications cell.

However, in mobile terminal apparatuses in the case where the Half-duplex FDD scheme is applied, optimization of operation still remains as an issue.

The present invention was made in view of such a respect, and it is an object of the invention to provide a mobile terminal apparatus, base station apparatus and communication control method that enable the Half-duplex FDD scheme to be optimized.

A mobile terminal apparatus of the invention is a mobile terminal apparatus that performs radio communications with a base station apparatus by a half-duplex scheme, and is characterized by having a transmission/reception section configured to transmit an uplink signal to the base station apparatus, and receive a downlink signal from the base station apparatus, and a control section configured to cause the transmission/reception section to selectively perform transmission of the uplink signal and reception of the downlink signal, based on a priority relationship defined between the uplink signal and the downlink signal, when transmission timing of the uplink signal and reception timing of the downlink signal overlaps each other.

According to the invention, in the mobile terminal apparatus, when transmission timing of the uplink signal and reception timing of the downlink signal overlaps each other, transmission and reception processing is selectively performed. Accordingly, it is possible to cause the mobile terminal apparatus to which the half-duplex scheme is applied to perform optimal operation when transmission timing of the uplink signal and reception timing of the downlink signal overlaps each other.

<FIG> is a diagram to explain a frequency usage state when mobile communications are performed in downlink. In addition, in all figures to explain the Embodiment, components having the same functions are assigned the same reference numerals to omit redundant descriptions. The example as shown in <FIG> is of the frequency usage state in the case of coexistence of LTE-A systems that are first communication systems having first relatively wide system bands comprised of a plurality of component carriers, and LTE systems that are second communication systems having a second relatively narrow system band (herein, comprised of a single component carrier). In the LTE-A systems, for example, radio communications are performed with a variable system bandwidth of <NUM> or less, and in the LTE systems, radio communications are performed with a variable system bandwidth of <NUM> or less. The system band of the LTE-A system is at least one base frequency region (component carrier: CC) with a system band of the LTE system as a unit. Thus integrating a plurality of base frequency regions to broaden the band is referred to as carrier aggregation.

For example, in <FIG>, the system band of the LTE-A system is a system band (<NUM> MHzx5=<NUM>) containing bands of five component carriers where the system band (base band: <NUM>) of the LTE system is one component carrier. In <FIG>, a mobile terminal apparatus UE (User Equipment) #<NUM> is a mobile terminal apparatus supporting the LTE-A system (also supporting the LTE system), and has the system band of <NUM>, UE#<NUM> is a mobile terminal apparatus supporting the LTE-A system (also supporting the LTE system), and has the system band of <NUM> (<NUM> MHzx2=<NUM>), and UE#<NUM> is a mobile terminal apparatus supporting the LTE system (not supporting the LTE-A system), and has the system band of <NUM> (base band).

In addition, mobile terminal apparatus UEs of LTE system (Rel. <NUM>) and its successor system (LTE-A system) support a Half-duplex FDD scheme (hereinafter, referred to as HD-FDD) as a duplex scheme. In HD-FDD, as shown in <FIG>, uplink transmission/reception and downlink transmission/reception of a mobile terminal apparatus UE is divided both in frequency and time. Accordingly, the mobile terminal apparatus does simultaneously not perform uplink transmission and downlink reception.

In this case, in switching from downlink to uplink, the mobile terminal apparatus gives priority to transmitting an uplink subframe from the beginning, and ignores an end portion of a downlink subframe. Meanwhile, in switching from uplink to downlink, the mobile terminal apparatus controls uplink transmission timing to reserve a time to switch to downlink. However, such an operation of the mobile terminal apparatus is dependent on scheduling of the base station apparatus, and when uplink transmission and downlink reception occurs at the same time, there is a problem that the mobile terminal apparatus is not able to operate properly.

Therefore, the inventors of the present invention arrived at the invention to solve the problems. In other words, it is the gist of the invention to cause a mobile terminal apparatus to perform transmission/reception based on a priority relationship between an uplink signal and a downlink signal when uplink transmission timing and downlink reception timing overlaps each other in the mobile terminal apparatus. By this means, it is possible to optimize the operation of the mobile terminal apparatus to which is applied HD-FDD.

Herein, described is the operation of the mobile terminal apparatus when uplink transmission timing and downlink reception timing overlaps each other. <FIG> contains operation explanatory views of the mobile terminal apparatus when uplink transmission timing and downlink reception timing overlaps each other.

When uplink transmission timing and downlink reception timing overlaps each other in a mobile terminal apparatus, the mobile terminal apparatus performs following four patterns of operation corresponding to the priority relationship between an uplink signal and a downlink signal. In a first pattern as shown in <FIG>, the mobile terminal apparatus gives a higher priority to transmission processing of an uplink signal than reception processing of a downlink signal. For example, when the uplink signal is more important (has a higher priority) than the downlink signal, the mobile terminal apparatus gives priority to transmission processing of the uplink signal. In addition, the mobile terminal apparatus does always not give priority to transmission processing of an uplink signal every time, and is capable of giving priority to reception processing of a downlink signal in a particular subframe corresponding to instructions from a base station apparatus.

In a second pattern as shown in <FIG>, the mobile terminal apparatus gives a higher priority to reception processing of a downlink signal than transmission processing of an uplink signal. For example, when the downlink signal is more important (has a higher priority) than the uplink signal, the mobile terminal apparatus gives priority to reception processing of the downlink signal. In addition, the mobile terminal apparatus does always not give priority to reception processing of a downlink signal every time, and is capable of giving priority to transmission processing of an uplink signal in a particular subframe corresponding to instructions from a base station apparatus.

In a third pattern as shown in <FIG>, the mobile terminal apparatus performs both transmission processing of an uplink signal and reception processing of a downlink signal in a single subframe. For example, the mobile terminal apparatus gives priority to reception processing of the downlink signal up to some point of a subframe, while giving priority to transmission processing of the uplink signal in remaining symbols. In this case, by using a PUCCH format for HD-FDD or PRACH format for HD-FDD as described later, the mobile terminal apparatus may perform transmission processing of an uplink signal and reception processing of a downlink signal in the same subframe.

In a fourth pattern as shown in <FIG>, the mobile terminal apparatus performs neither transmission processing of an uplink signal nor reception processing of a downlink signal. For example, when the uplink signal and downlink signal are both important (priorities are the same), the mobile terminal apparatus regards as erroneous detection of signals, and halts transmission/reception processing of the downlink signal and uplink signal.

Described next is the priority relationship between uplink signals and downlink signals. <FIG> is a table showing an example of the priority relationship between uplink signals and downlink signals. In addition, the priority relationship and kinds of signals as shown in <FIG> are not limited thereto, and are capable of being modified as appropriate.

Herein, as uplink signals, exemplified area PUSCH signal, Periodic CQI (Channel Quality Indicator), ACK (Acknowledgement)/NACK (Negative Acknowledgement), Positive SR (Scheduling Request), SRS (Sounding Reference Signal), and PRACH signal. The PUSCH signal is transmitted on a PUSCH (Physical Uplink Shared Channel) as an uplink data channel shared among a plurality of mobile terminals , and includes user data and control information of higher layer. The Periodic CQI is transmitted on a PUCCH (Physical Uplink Control Channel) as an uplink control channel, and is channel quality information of downlink required for scheduling of downlink user data and adaptive link control.

The ACK/NACK is response information to a PDSCH transmitted on the PUCCH. The Positive SR is transmitted on the PUCCH, and request information for requesting a base station apparatus to add to scheduling in order for the mobile terminal apparatus to transmit newly occurring data. The SRS is a reference signal used for measurement of a CQI of uplink for each frequency of the mobile terminal apparatus. The PRACH signal is transmitted on a PRACH (Physical Random Access Channel) as an access channel, and is a collision type signal for the mobile terminal apparatus to perform setting of a communication start and the like in initial access.

Further, herein, as downlink signals, exemplified are a PDSCH signal, PDCCH signal, PHICH signal, CSI-RS (Channel State Information - Reference Signal), and PBCH signal. The PDSCH signal is transmitted on a PDSCH (Physical Downlink Shared Channel) as a downlink data channel shared among mobile terminal apparatuses, and includes user data and control information of higher layer. The PDCCH signal is transmitted on a PDCCH (Physical Downlink Control Channel) as a downlink control channel, and includes scheduling information of the PUSCH and PDCCH by a scheduler and the like.

The PHICH signal is transmitted on a PHICH (Physical HARQ Indicator Channel) as a downlink control channel, and is ACK/NACK (response information) to the PUSCH. The CSI-RS is a reference signal used in CSI measurement for CQI, PMI (Precoding Matrix Indicator), RI (Rank Indicator) and the like as a channel state. The PBCH signal is transmitted on a PBCH (Physical Broadcast Channel) as a broadcast channel, and includes system-specific and cell-specific control information broadcasted to the entire cell.

The priority relationship between each uplink signal and each downlink signal described above will be described below. The priority relationship is set on both the mobile terminal apparatus and the base station apparatus, is used by the mobile terminal apparatus in selection of transmission/reception processing, and is used by the base station apparatus mainly in demodulation of an uplink signal from the mobile terminal apparatus.

As shown in <FIG>, the priority of a PUSCH signal in uplink is defined to be the same as the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of the PUSCH signal and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus neither transmits nor receives any of the signals, and regards as erroneous detection of signals.

The priority of a PUSCH signal in uplink is defined to be higher than the priority of a PDCCH signal in downlink. Accordingly, when transmission timing of the PUSCH signal and reception timing of the PDCCH signal overlaps each other, the mobile terminal apparatus transmits the PUSCH signal. In addition, the mobile terminal apparatus may give a higher priority to reception of the PDCCH signal than transmission of the PUSCH signal in a particular subframe. The particular subframe may be notified semi-statically from the base station apparatus to the mobile terminal apparatus by RRC signaling or the like, or may be notified dynamically from the base station apparatus to the mobile terminal apparatus by adding a control bit of the PDCCH signal.

The priority of a PUSCH signal in uplink is defined to be lower than the priority of a PHICH signal in downlink. Accordingly, when transmission timing of the PUSCH signal and reception timing of the PHICH signal overlaps each other, the mobile terminal apparatus receives the PHICH signal.

The priority of a PUSCH signal in uplink is defined to be higher than the priority of a CSI-RS in downlink. Accordingly, when transmission timing of the PUSCH signal and reception timing of the CSI-RS overlaps each other, the mobile terminal apparatus transmits the PUSCH signal.

The priority of a PUSCH signal in uplink is defined to be higher than the priority of a PBCH signal in downlink. Accordingly, when transmission timing of the PUSCH signal and reception timing of the PBCH signal overlaps each other, the mobile terminal apparatus transmits the PUSCH signal. In addition, the mobile terminal apparatus may give a higher priority to reception of the PBCH signal than transmission of the PUSCH signal in a particular subframe. The particular subframe may be notified by RRC signaling or the like, or may be notified by adding a control bit of the PDCCH signal.

The priority of a Periodic CQI in uplink is defined to be higher than the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of the Periodic CQI and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus transmits the Periodic CQI.

The priority of a Periodic CQI in uplink is defined to be higher than the priority of a PDCCH signal in downlink. Accordingly, when transmission timing of the Periodic CQI and reception timing of the PDCCH signal overlaps each other, the mobile terminal apparatus transmits the Periodic CQI. In addition, the mobile terminal apparatus may perform transmission of the Periodic CQI and reception of the PDCCH signal in the same subframe, using a PUCCH format for HD-FDD. The PUCCH format for HD-FDD will specifically be described later.

The priority of a Periodic CQI in uplink is defined to be lower than the priority of a PHICH signal in downlink. Accordingly, when transmission timing of the Periodic CQI and reception timing of the PHICH signal overlaps each other, the mobile terminal apparatus receives the PHICH. In addition, the mobile terminal apparatus may perform transmission of the Periodic CQI and reception of the PHICH signal in the same subframe, using the PUCCH format for HD-FDD.

The priority of a Periodic CQI in uplink is defined to be higher than the priority of a CSI-RS in downlink. Accordingly, when transmission timing of the Periodic CQI and reception timing of the CSI-RS overlaps each other, the mobile terminal apparatus transmits the Periodic CQI. In addition, the mobile terminal apparatus may give a higher priority to reception of the CSI-RS than transmission of the Periodic CQI in a particular subframe. The particular subframe may be notified by RRC signaling or the like, or may be notified by adding a control bit to the PDCCH signal.

The priority of a Periodic CQI in uplink is defined to be higher than the priority of a PBCH signal in downlink. Accordingly, when transmission timing of the Periodic CQI and reception timing of the PBCH signal overlaps each other, the mobile terminal apparatus transmits the Periodic CQI. In addition, the mobile terminal apparatus may give a higher priority to reception of the PBCH signal than transmission of the Periodic CQI in a particular subframe. The particular subframe may be notified by RRC signaling or the like, or may be notified by adding a control bit to the PDCCH signal.

The priority of ACK/NACK in uplink is defined to be higher than the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of ACK/NACK and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus transmits ACK/NACK.

The priority of ACK/NACK in uplink is defined to be higher than the priority of a PDCCH signal in downlink. Accordingly, when transmission timing of ACK/NACK and reception timing of the PDCCH signal overlaps each other, the mobile terminal apparatus transmits ACK/NACK. In addition, the mobile terminal apparatus may perform transmission of ACK/NACK and reception of the PDCCH signal in the same subframe, using the PUCCH format for HD-FDD.

The priority of ACK/NACK in uplink is defined to be the same as the priority of a PHICH signal in downlink. Accordingly, when transmission timing of ACK/NACK and reception timing of the PHICH signal overlaps each other, the mobile terminal apparatus neither transmits nor receives any of the signals, and regards as erroneous detection of signals.

The priority of ACK/NACK in uplink is defined to be higher than the priority of a CSI-RS in downlink. Accordingly, when transmission timing of ACK/NACK and reception timing of the CSI-RS overlaps each other, the mobile terminal apparatus transmits ACK/NACK.

The priority of ACK/NACK in uplink is defined to be higher than the priority of a PBCH signal in downlink. Accordingly, when transmission timing of ACK/NACK and reception timing of the PBCH signal overlaps each other, the mobile terminal apparatus transmits ACK/NACK.

The priority of a Positive SR in uplink is defined to be lower than the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of the Positive SR and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus receives the PDSCH signal.

The priority of a Positive SR in uplink is defined to be higher than the priority of a PDCCH signal in downlink. Accordingly, when transmission timing of the Positive SR and reception timing of the PDCCH signal overlaps each other, the mobile terminal apparatus transmits the Positive SR. In addition, the mobile terminal apparatus may perform transmission of the Positive SR and reception of the PDCCH signal in the same subframe, using the PUCCH format for HD-FDD.

The priority of a Positive SR in uplink is defined to be lower than the priority of a PHICH signal in downlink. Accordingly, when transmission timing of the Positive SR and reception timing of the PHICH signal overlaps each other, the mobile terminal apparatus receives the PHICH signal. In addition, the mobile terminal apparatus may perform transmission of the Positive SR and reception of the PHICH signal in the same subframe, using the PUCCH format for HD-FDD.

The priority of a Positive SR in uplink is defined to be higher than the priority of a CSI-RS in downlink. Accordingly, when transmission timing of the Positive SR and reception timing of the CSI-RS overlaps each other, the mobile terminal apparatus transmits the Positive SR.

The priority of a Positive SR in uplink is defined to be higher than the priority of a PBCH signal in downlink. Accordingly, when transmission timing of the Positive SR and reception timing of the PBCH signal overlaps each other, the mobile terminal apparatus transmits the Positive SR. In addition, the mobile terminal apparatus may give a higher priority to reception of the PBCH signal than transmission of the Positive SR in a particular subframe. The particular subframe may be notified by RRC signaling or the like, or may be notified by adding a control bit to the PDCCH signal.

The priority of an SRS in uplink is defined to be higher than the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of the SRS and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus transmits the SRS. In addition, although details will be described later, the base station apparatus may transmit the SRS in uplink after receiving the PDSCH signal up to some point in downlink.

An SRS in uplink is assigned to a different symbol from that of a PDCCH signal in downlink in the same subframe. Accordingly, transmission of the SRS and reception of the PDCCH is performed in the same subframe. In addition, priories may be defined or may not be defined between an SRS and a PDCCH signal.

An SRS in uplink is assigned to a different symbol from that of a PHICH signal in downlink in the same subframe. Accordingly, transmission of the SRS and reception of the PHICH is performed in the same subframe. In addition, priories may be defined or may not be defined between an SRS and a PHICH signal.

When an SRS in uplink is assigned to a different symbol from that of a CSI-RS in downlink in the same subframe, transmission of the SRS and reception of the CSI-RS is performed in the same subframe. In this case, priories may be defined or may not be defined between an SRS and a CSI-RS. Meanwhile, when an SRS is assigned to the same symbol as that of a CSI-RS in the same subframe, one of priorities of the SRS and CSI-RS is defined to be higher. By this means, priority is given to processing of a signal of a higher priority between the SRS and the CSI-RS.

An SRS in uplink is assigned to a different symbol from that of a PBCH signal in downlink in the same subframe. Accordingly, transmission of the SRS and reception of the PBCH signal is performed in the same subframe. In addition, priories may be defined or may not be defined between an SRS and a PBCH signal.

The priority of a PRACH signal in uplink is defined to be lower than the priority of a PDSCH signal in downlink. Accordingly, when transmission timing of the PRACH signal and reception timing of the PDSCH signal overlaps each other, the mobile terminal apparatus receives the PDSCH signal.

The priority of a PRACH signal in uplink is defined to be higher than the priority of a PDCCH signal in downlink. Accordingly, when transmission timing of the PRACH signal and reception timing of the PDCCH signal overlaps each other, the mobile terminal apparatus transmits the PRACH signal. In addition, the mobile terminal apparatus may perform transmission of the PRACH signal and reception of the PDCCH signal in the same subframe, using a PRACH format for HD-FDD.

The priority of a PRACH signal in uplink is defined to be lower than the priority of a PHICH signal in downlink. Accordingly, when transmission timing of the PRACH signal and reception timing of the PHICH signal overlaps each other, the mobile terminal apparatus receives the PHICH signal. In addition, the mobile terminal apparatus may perform transmission of the PRACH signal and reception of the PHICH signal in the same subframe, using the PRACH format for HD-FDD.

The priority of a PRACH signal in uplink is defined to be higher than the priority of a CSI-RS in downlink. Accordingly, when transmission timing of the PRACH signal and reception timing of the CSI-RS overlaps each other, the mobile terminal apparatus transmits the PRACH signal.

The priority of a PRACH signal in uplink is defined to be higher than the priority of a PBCH signal in downlink. Accordingly, when transmission timing of the PRACH signal and reception timing of the PBCH signal overlaps each other, the mobile terminal apparatus transmits the PRACH signal. In addition, the mobile terminal apparatus may give a higher priority to reception of the PBCH signal than transmission of the PRACH signal in a particular subframe. The particular subframe may be notified by RRC signaling or the like, or may be notified by adding a control bit of the PDCCH signal.

By thus defining the priority relationship between an uplink signal and a downlink signal, even when transmission timing of the uplink signal and reception timing of the downlink signal overlaps each other, it is possible to cause the mobile terminal apparatus to perform transmission/reception processing of an important signal with reliability. In addition, the priority relationship as described above is defined while giving a higher priority mainly to an uplink signal than a downlink signal, but is not limited thereto. The priority relationship is capable of being modified as appropriate corresponding to the network configuration, base station apparatus configuration, mobile terminal apparatus configuration and the like.

Transmission/reception methods of uplink signal and downlink signal in the same subframe as described above will specifically be described with reference to <FIG> contains explanatory views of transmission/reception methods of uplink signal and downlink signal in the same subframe.

A first transmission/reception method as shown in <FIG> is a transmission/reception method in which a mobile terminal apparatus receives a downlink signal up to some point in a subframe, and then, transmits an uplink signal in remaining symbols. Herein, the description is given by exemplifying a PDCCH signal and PDSCH signal as downlink signals, and an SRS as an uplink signal, but is not limited to these signals, and it is possible to modify as appropriate.

Generally, an uplink SRS is assigned to a different symbol from that of a downlink PDCCH signal in the same subframe, but overlaps a symbol assigned to part of a downlink PDSCH signal. Therefore, as shown in <FIG>, the mobile terminal apparatus ignores last several symbols (<NUM> symbols in this Embodiment) of the PDSCH signal for the SRS. The mobile terminal apparatus receives the PDCCH signal of first <NUM> symbols from the base station apparatus, while receiving the PDSCH signal up to symbols two-symbol-before the last symbol. Subsequently, the mobile terminal apparatus uses a symbol immediately before the last symbol as a guard interval to switch from the downlink reception processing to the uplink transmission processing, and transmits the SRS to the base station apparatus in the last symbol.

Further, the base station apparatus may perform rate matching processing or puncturing processing on a PDSCH signal to transmit the PDSCH signal with two symbols being vacant corresponding to an SRS and guard interval reserved in a single subframe. In this case, the base station apparatus performs the rate matching processing or the like of the PDSCH signal based on the priority relationship defined between the uplink signal and the downlink signal. The mobile terminal apparatus receives the PDCCH signal and PDSCH signal from the base station apparatus. Subsequently, the mobile terminal apparatus uses a symbol immediately before the last symbol as a guard interval to switch from the downlink reception processing to the uplink transmission processing, and transmits the SRS to the base station apparatus in the last symbol reserved for the SRS.

In addition, in the above-mentioned first transmission/reception method, the downlink signal is received up to some point, and then, the uplink signal is received in the remaining symbols. Alternatively, the uplink signal may be transmitted up to some point, and then, the downlink signal may be received in the remaining symbols. Further, in <FIG>, it is preferable that last two symbols of the PDSCH signal are not assigned important data.

A second transmission/reception method as shown in <FIG> is a transmission/reception method for performing transmission of an uplink signal and reception of a downlink signal in the same subframe, using a signal format for HD-FDD in a single subframe. Herein, the description is given by exemplifying a PDCCH signal and PHICH signal that are downlink L1/L2 control signals as downlink signals, and a PUCCH signal and PRACH signal as uplink signals, but is not limited to these signals, and it is possible to modify as appropriate.

Generally, a PUCCH signal in uplink is assigned to the entire subframe, and therefore, overlaps symbols assigned to a PDCCH signal and PHICH signal in downlink in the same subframe. Therefore, as shown in <FIG>, the mobile terminal apparatus uses a PUCCH format for HD-FDD in which first several symbols (<NUM> symbols in this Embodiment) of a PUCCH are punctured or undergo rate matching so as to avoid a PDCCH signal and PHICH signal. The mobile terminal apparatus receives the PDCCH signal and PHICH signal from the base station apparatus in first <NUM> symbols of the PUCCH format for HD-FDD undergoing puncturing or the like. Subsequently, the mobile terminal apparatus uses a 4th symbol of the PUCCH format for HD-FDD as a guard interval to switch from the downlink reception processing to the uplink transmission processing, and transmits the PUCCH signal to the base station apparatus in the remaining symbols.

Further, generally, a PRACH signal in uplink is assigned to the entire subframe, and therefore, overlaps symbols assigned to a PDCCH signal and PHICH signal in downlink in the same subframe. Therefore, as shown in <FIG>, the mobile terminal apparatus uses a PRACH format for HD-FDD in which first several symbols (<NUM> symbols in this Embodiment) of a PRACH are punctured so as to avoid a PDCCH signal and PHICH signal. The mobile terminal apparatus receives the PDCCH signal and PHICH signal from the base station apparatus in first <NUM> symbols of the PRACH format for HD-FDD undergoing puncturing. Subsequently, the mobile terminal apparatus uses a 4th symbol of the PRACH format for HD-FDD as a guard interval to switch from the downlink reception processing to the uplink transmission processing, and transmits the PRACH signal to the base station apparatus in the remaining symbols.

Moreover, the base station apparatus may use an uplink signal format for HD-FDD in which a part of symbols of an uplink signal undergoes puncturing or rate matching so as to avoid a downlink signal. The mobile terminal apparatus receives a PUSCH signal of a part of the uplink signal format, while transmitting an uplink signal in the remaining symbols.

In addition, in the above-mentioned second transmission/reception method, a signal format for HD-FDD may be used with first several symbols being vacant, or a signal format for HD-FDD may be used with last several symbols being vacant or middle several symbols being vacant. Further, an uplink signal format and downlink signal format may be combined to use.

Moreover, the transmission/reception method of uplink signal and downlink signal in the same subframe is not limited to the first transmission/reception method and the second transmission/reception method. Any method is capable of being used, as long as the method enables the mobile terminal apparatus to perform transmission processing of an uplink signal and reception processing of a downlink signal in the same subframe.

A radio communication system according to the Embodiment of the invention will specifically be described herein. <FIG> is an explanatory view of a system configuration of the radio communication system according to this Embodiment. In addition, the radio communication system as shown in <FIG> is a system including the LTE system or SUPER <NUM>, for example. Further, the radio communication system may be called IMT-Advanced or may be called <NUM>.

As shown in <FIG>, the radio communication system <NUM> includes the base station apparatus <NUM>, and a plurality of mobile terminal apparatuses <NUM> (<NUM><NUM>, <NUM><NUM>, <NUM><NUM>,. ,<NUM>n, n is an integer where n><NUM>) that communicate with the base station apparatus <NUM> and is comprised thereof. The base station apparatus <NUM> is connected to an upper station apparatus <NUM>, and the upper station apparatus <NUM> is connected to a core network <NUM>. The mobile terminal apparatuses <NUM> are capable of communicating with the base station apparatus <NUM> in a cell <NUM>. In addition, for example, the upper station apparatus <NUM> includes an access gateway apparatus, radio network controller (RNC), mobility management entity (MME), etc., but is not limited thereto.

Each of the mobile terminal apparatuses (<NUM><NUM>, <NUM><NUM>, <NUM><NUM>,. ,<NUM>n) includes an LTE terminal and LTE-A terminal, and is described as a mobile terminal apparatus <NUM> unless otherwise specified in the following description. Further, for convenience in description, the description is given while assuming that equipment that performs radio communications with the base station apparatus <NUM> is the mobile terminal apparatus <NUM>, and more generally, the equipment may be user equipment (UE) including mobile terminal apparatuses and fixed terminal apparatuses.

In the radio communication system <NUM>, as a radio access scheme, OFDMA (Orthogonal Frequency Division Multiple Access) is applied in downlink, while SC-FDMA (Single-Carrier Frequency Division Multiple Access) is applied in uplink, but the uplink radio access scheme is not limited thereto. OFDMA is a multicarrier transmission scheme for dividing a frequency band into a plurality of narrow frequency bands (subcarriers), and mapping data to each subcarrier to perform communications. SC-FDMA is a single-carrier transmission scheme for dividing the system band into bands comprised of a single or consecutive resource blocks for each terminal so that a plurality of terminals uses mutually different bands, and thereby reducing interference among the terminals.

Referring to <FIG>, described is the entire configuration of the base station apparatus <NUM> according to this Embodiment. The base station apparatus <NUM> is provided with a transmission/reception antenna <NUM>, transmission/reception section <NUM>, baseband signal processing section <NUM>, call processing section <NUM> and transmission path interface <NUM>. The user data to transmit from the base station apparatus <NUM> to the mobile terminal apparatus <NUM> in downlink is input to the baseband signal processing section <NUM> via the transmission path interface <NUM> from the upper station apparatus <NUM>.

The baseband signal processing section <NUM> performs PDCP layer processing, segmentation and concatenation of the user data, RLC (Radio Link Control) layer transmission processing such as transmission processing of RLC retransmission control, MAC (Medium Access Control) retransmission control e.g. HARQ transmission processing, scheduling, transmission format selection, channel coding, Inverse Fast Fourier Transform processing and precoding processing. Further, on a signal of the Physical Downlink Control Channel that is a downlink control channel, the section <NUM> also performs transmission processing of channel coding, Inverse Fast Fourier Transform and the like.

Further, the baseband signal processing section <NUM> notifies the mobile terminal apparatus <NUM> of control information for communications in the cell on the broadcast channel. For example, the control information includes the system bandwidth in uplink or downlink, identification information (Root Sequence Index) of a root sequence to generate a signal of a random access preamble on the PRACH, etc..

The transmission/reception section <NUM> converts the frequency of the baseband signal output from the baseband signal processing section <NUM> into a radio frequency band, and amplifies the signal to output to the transmission/reception antenna <NUM>.

Meanwhile, with respect to signals transmitted from the mobile terminal apparatus <NUM> to the base station apparatus <NUM> in uplink, a radio frequency signal received in the transmission/reception antenna <NUM> is amplified in the transmission/reception section <NUM>, while being converted into a baseband signal, and is input to the baseband signal processing section <NUM>.

The baseband signal processing section <NUM> performs FFT processing, IDFT processing, error correcting decoding, reception processing of MAC retransmission control, and reception processing of RLC layer and PDCP layer on the user data included in the baseband signal received in uplink. The decoded signal is transferred to the upper station apparatus <NUM> via the transmission path interface <NUM>.

The call processing section <NUM> performs call processing such as setting and release of the communication channel, status management of the base station apparatus <NUM>, and management of radio resources.

Referring to <FIG>, described next is the entire configuration of the mobile terminal apparatus <NUM> according to this Embodiment. The LTE terminal and the LTE-A terminal have the same conf iguration of principal part of hardware, and are not distinguished to describe. The mobile terminal apparatus <NUM> is provided with a transmission/reception antenna <NUM>, transmission/reception section <NUM>, baseband signal processing section <NUM> and application section <NUM>.

With respect to data in downlink, a radio frequency signal received in the transmission/reception antenna <NUM> is amplified in the transmission/reception section <NUM>, while being subjected to frequency conversion, and is converted into a baseband signal. The baseband signal is subjected to FFT processing, error correcting decoding, reception processing of retransmission control, etc. in the baseband signal processing section <NUM>. Among the data in downlink, the user data in downlink is transferred to the application section <NUM>. The application section <NUM> performs processing concerning layers higher than the physical layer and MAC layer and the like. Further, among the data in downlink, the broadcast information is also transferred to the application section <NUM>.

Meanwhile, with respect to user data in uplink, the application section <NUM> inputs the data to the baseband signal processing section104. The baseband signal processing section <NUM> performs transmission processing of retransmission control (HARQ), channel coding, DFT processing and IFFT processing. The transmission/reception section <NUM> converts the frequency of the baseband signal output from the baseband signal processing section <NUM> into a radio frequency band, and amplifies the signal to output to the transmission/reception antenna <NUM>.

Functional blocks of the base station apparatus according to this Embodiment will be described with reference to <FIG>. Inaddition, <FIG> mainly shows functional blocks of the baseband processing section and transmission/reception section. Further, <FIG> simplifies the baseband processing section and transmission/reception section, and it is assumed to have configurations generally provided in the baseband processing section and transmission/reception section. The base station apparatus <NUM> has a PBCH signal generating section <NUM>, PDCCH signal generating section212, PHICH signal generating section <NUM>, PDSCH signal generating section <NUM>, CSI-RS generating section <NUM>, physical channel multiplexing section <NUM>, IFFT section <NUM>, CP adding section <NUM>, and transmission RF circuit 203b, as a transmission system.

The PBCH signal generating section <NUM> generates a PBCH signal including basic parameters of a bandwidth, control channel configuration, etc. The PDCCH signal generating section <NUM> generates a PDCCH signal including format information such as a modulation method and coding rate, in addition to scheduling information of the PUSCH signal and PDSCH signal, for each user, based on allocation by a scheduler <NUM>. The PHICH signal generating section <NUM> generates a PHICH signal for HARQ (Hybrid Automatic Repeat reQuest) to the PUSCH signal based on allocation by the scheduler <NUM>. The PDSCH signal generating section <NUM> generates a PDSCH signal including user data and control information of a higher layer shared by a plurality of mobile terminal apparatuses <NUM>, based on allocation by the scheduler <NUM>. The CSI-RS generating section <NUM> generates a CSI-RS used only for measurement of channel state information.

The physical channel multiplexing section <NUM> multiplexes downlink signals which are coded and modulated in respective signal generating sections to input to the IFFT section <NUM>. The IFFT section <NUM> performs IFFT (Inverse Fast Fourier Transform) on the multiplexed downlink signal, and transforms the signal in the frequency domain into a time-series signal. The CP adding section <NUM> inserts a cyclic prefix in the downlink signal. Then, the downlink signal passes through the transmission RF circuit 203b, and is transmitted from the transmission/reception antenna <NUM> via a duplexer 203c provided inbetween the transmission system and a reception system.

As the reception system, the base station apparatus <NUM> has a PUSCH signal demodulation · decoding section <NUM>, PUCCH signal demodulation · decoding section <NUM>, PRACH signal reception section <NUM>, SRS reception section <NUM>, physical channel dividing section <NUM>, FFT section <NUM>, CP removing section <NUM> and reception RF circuit 203a. An uplink signal received in the transmission/reception antenna <NUM> is input to the CP removing section <NUM> via the duplexer 203c and reception RF circuit 203a. The CP removing section <NUM> removes the cyclic prefix from the uplink signal to input to the FFT section <NUM>. The FFT section <NUM> performs Fast Fourier Transform (FFT) on the uplink signal, and transforms the time-series signal into a signal in the frequency domain to input to the physical channel dividing section <NUM>. The physical channel dividing section <NUM> divides uplink signals multiplexed into the uplink signal into respective signals.

The PUSCH signal demodulation · decoding section <NUM> demodulates a PUSCH signal including user data and control information of a higher layer shared by a plurality of mobile terminal apparatuses <NUM>, based on allocation by the scheduler <NUM>, and further decodes the signal. The PUCCH signal demodulation · decoding section <NUM> demodulates a PUCCH signal including a Periodic CQI, ACK/NACK to the PDSCH and Positive SR, based on allocation of the scheduler <NUM>, and further decodes the signal. The PRACH signal reception section <NUM> receives a collision type PRACH signal used in initial access of the mobile terminal apparatus <NUM>. The SRS reception section <NUM> receives an SRS to perform scheduling by the scheduler <NUM> and adaptive control.

The scheduler <NUM> controls resource allocation to mobile terminal apparatuses <NUM> under the base station apparatus corresponding to communication quality of the entire system band. The scheduler <NUM> distinguishes between an LTE terminal user and an LTE-A terminal user to perform scheduling. To the scheduler <NUM> are input transmission data and retransmission instructions from the upper station apparatus <NUM>, and a channel estimation value and CQI of a resource block from the reception section that measures the uplink signal. The scheduler <NUM> performs scheduling of the PDCCH signal, PHICH signal and PDSCH signal, while referring to the retransmission instructions input from the upper station apparatus <NUM>, channel estimation value and CQI. In a propagation path in mobile communications, variations vary with frequencies by frequency selective fading. Then, in transmitting user data to mobile terminal apparatuses <NUM>, the scheduler <NUM> allocates resource blocks with good communication quality for each subframe to each mobile terminal apparatus <NUM> (called adaptive frequency scheduling). In adaptive frequency scheduling, a mobile terminal apparatus <NUM> of good propagation path quality is selected and allocated for each resource block. Therefore, the scheduler <NUM> uses CQIs on a basis of a resource block transmitted from each mobile terminal apparatus <NUM> as feedback to allocate resource blocks. Further, the scheduler <NUM> determines an MCS (coding rate, modulation scheme) meeting a predetermined block error rate in the allocated resource block. A parameter satisfying the MCS determined in the scheduler <NUM> is set on the PDCCH signal generating section <NUM>, PHICH signal generating section <NUM> and PDSCH signal generating section <NUM>.

Further, the scheduler <NUM> controls demodulation and decoding of the PUSCH signal demodulation · decoding section <NUM> and PUCCH signal demodulation · decoding section <NUM>, in consideration of the above-mentioned priority relationship. When transmission and reception timing of uplink and downlink signals in the mobile terminal apparatus <NUM> overlaps each other, the PUSCH signal demodulation · decoding section <NUM> and PUCCH signal demodulation · decoding section <NUM> need to determine whether the uplink signal is transmitted to the base station apparatus <NUM>. Therefore, the scheduler <NUM> inputs, to the PUSCH signal demodulation · decoding section <NUM> and PUCCH signal demodulation · decoding section <NUM>, which transmission of the uplink signal or reception of the downlink signal is given a higher priority in the mobile terminal apparatus <NUM> in a predetermined subframe based on the above-mentioned priority relationship.

Furthermore, the base station apparatus <NUM> has a signal format selecting section <NUM>. When uplink and downlink signals are received and transmitted in the same subframe, the signal format selecting section <NUM> selects the signal format as shown in <FIG>, based on allocation by the scheduler <NUM>. When the transmission/reception method in the same subframe is controlled on the base station apparatus <NUM> side, the signal format selecting section <NUM> inputs signal format information to the signal generating sections. For example, based on the signal format information, on the premise that the mobile terminal apparatus <NUM> does not receive last several symbols of the subframe as shown in <FIG>, the PDSCH signal generating section <NUM> may perform rate matching processing or puncturing processing on the PDSCH signal. Further, for example, the PDSCH signal generating section <NUM> may generate the PDSCH format for HD-FDD in which the PDSCH signal undergoes rate matching or puncturing so as to avoid the downlink signal, based on the signal format information.

Meanwhile, when the transmission/reception method in the same subframe is controlled on the mobile terminal apparatus <NUM> side, the signal format selecting section inputs the signal format information to the demodulation · decoding sections and reception sections. By this means, even when transmission and reception timing of downlink and uplink signals overlaps each other in the same subframe, the demodulation · decoding sections and reception sections are capable of recognizing symbols in which an uplink signal is transmitted. For example, the PUCCH signal demodulation · decoding section <NUM> recognizes symbols assigned a PUCCH signal in a single subframe based on the signal format information, demodulates the PUCCH signal, and further decodes the signal.

Functional blocks of the mobile terminal apparatus according to this Embodiment will be described with reference to <FIG>. In addition, <FIG> mainly shows functional blocks of the baseband processing section and transmission/reception section. Further, <FIG> simplifies the baseband processing section and transmission/reception section, and it is assumed to have configurations generally provided in the baseband processing section and transmission/reception section. The mobile terminal apparatus <NUM> has a PUSCH signal generating section <NUM>, PUCCH signal generating section <NUM>, PRACH signal generating section <NUM>, SRS generating section <NUM>, physical channel multiplexing section <NUM>, IFFT section <NUM>, CP adding section <NUM>, and transmission RF circuit 103b, as a transmission system.

The PUSCH signal generating section <NUM> generates a PUSCH signal shared among a plurality of mobile terminal apparatuses <NUM> based on scheduling information. The PUCCH signal generating section <NUM> generates a PUCCH signal including a Periodic CQI, ACK/NACK, and Positive SR. The PRACH signal generating section <NUM> generates a collision type PRACH signal used in initial access to the base station apparatus <NUM>. The SRS generating section <NUM> generates an SRS used in scheduling and adaptive control.

The physical channel multiplexing section <NUM> multiplexes uplink signals which are coded and modulated in respective signal generating sections to input to the IFFT section <NUM>. The IFFT section <NUM> performs IFFT (Inverse Fast Fourier Transform) on the multiplexed uplink signal, and transforms the signal in the frequency domain into a time-series signal. The CP adding section <NUM> inserts a cyclic prefix in the uplink signal. Then, the uplink signal passes through the transmission RF circuit 103b, and is transmitted from the transmission/reception antenna <NUM> via a switch 103c provided in between the transmission system and a reception system.

As the reception system, the base station apparatus <NUM> has a PBCH signal demodulation · decoding section <NUM>, PDCCH signal demodulation · decoding section <NUM>, PHICH signal demodulation · decoding section <NUM>, PDSCH signal demodulation · decoding section <NUM>, CSI-RS reception section <NUM>, physical channel dividing section <NUM>, FFT section <NUM>, CP removing section <NUM> and reception RF circuit 103a. A downlink signal received in the transmission/reception antenna <NUM> is input to the CP removing section <NUM> via the switch 103c and reception RF circuit 103a. The CP removing section <NUM> removes the cyclic prefix from the downlink signal to input to the FFT section <NUM>. The FFT section <NUM> performs Fast Fourier Transform (FFT) on the downlink signal, and transforms the time-series signal into a signal in the frequency domain to input to the physical channel dividing section <NUM>. The physical channel dividing section <NUM> divides downlink signals multiplexed into the downlink signal into respective signals.

The PBCH signal demodulation · decoding section <NUM> demodulates a PBCH signal including system information specific to the cell, and further decodes the signal. The PDCCH signal demodulation · decoding section <NUM> demodulates a PDCCH signal including scheduling information of a PUSCH signal and PDSCH signal for each user, and further decodes the signal. The PDCCH signal demodulation · decoding section <NUM> inputs scheduling information of uplink and downlink to a transmission/reception channel · signal format selecting section <NUM>. The PHICH signal demodulation · decoding section <NUM> demodulates a PHICH signal to the PUSCH, and further decodes the signal. The PHICH signal demodulation · decoding section <NUM> inputs whether or not to retransmit the PUSCH to the transmission/reception channel · signal format selecting section <NUM> based on the PHICH signal. The PDSCH signal demodulation · decoding section demodulates a PDSCH signal including user data and control information of a higher layer shared among a plurality of mobile terminal apparatuses <NUM>, and further decodes the signal. The CSI-RS reception section <NUM> demodulates a CSI-RS used only for measurement of channel state information, and further decodes the signal.

Further, the mobile terminal apparatus <NUM> has the transmission/reception channel · signal format selecting section <NUM>. The transmission/reception channel · signal format selecting section <NUM> determines a signal of a higher priority based on the priority relationship between uplink and downlink signals when transmission and reception timing of uplink and downlink signals overlaps each other. Then, based on the determination result, the transmission/reception channel · signal format selecting section <NUM> selects transmission processing of the uplink signal or reception processing of the downlink signal to give priority. More specifically, when the transmission processing of the uplink signal is given priority, the transmission/reception channel · signal format selecting section <NUM> switches the switch 103c to the transmission system side with switch timing information. By this means, the mobile terminal apparatus <NUM> transmits the uplink signal via the transmission/reception antenna <NUM>. When the reception processing of the downlink signal is given priority, the transmission/reception channel · signal format selecting section <NUM> switches the switch to the reception system side with the switch timing information. By this means, the mobile terminal apparatus <NUM> receives the downlink signal via the transmission/reception antenna <NUM>.

In this case, the transmission/reception channel · signal format selecting section <NUM> may switch the switch 103c contrary to the priority relationship in a particular subframe notified by RRC signaling or PDCCH signal. In other words, in the particular subframe, the section <NUM> may give priority to reception processing of the downlink signal of a lower priority than the uplink signal, or may give priority to transmission processing of the uplink signal of a lower priority than the downlink signal. Further, when neither transmission processing of the uplink signal nor reception processing of the downlink signal is performed, the transmission/reception channel · signal format selecting section <NUM> separates the switch 103c from the transmission system and reception system with the switch timing information. By this means, the mobile terminal apparatus <NUM> halts the transmission and reception processing of uplink signal and downlink signal.

Further, when uplink and downlink signals are transmitted and received in the same subframe, the transmission/reception channel · signal format selecting section <NUM> selects the signal format shown in any of <FIG>. When the transmission/reception method in the same subframe is controlled on the mobile terminal apparatus <NUM> side, the transmission/reception channel · signal format selecting section <NUM> inputs the signal format information to each signal generating section, each demodulation · decoding section and reception section.

For example, in the first transmission/reception method as shown in <FIG>, the PDSCH signal demodulation · decoding section <NUM> demodulates the PDSCH signal while leaving last several symbols based on the signal format information, and further decodes the signal. Further, the SRS generating section <NUM> generates an SRS in accordance with the last symbol. Meanwhile, in the second transmission/reception method as shown in <FIG>, the PUCCH signal generating section <NUM> selects the PUCCH format for HD-FDD based on the signal format information, and performs puncturing or rate matching on first several symbols to generate a PUCCH signal. Further, the PDCCH signal demodulation · decoding section <NUM> and PHICH signal demodulation · decoding section <NUM> demodulate the PDCCH signal and PHICH signal assigned to first several symbols based on the signal format information, and further decode the signals. Moreover, in the second transmission/reception method as shown in <FIG>, the PRACH signal generating section <NUM> selects the PRACH format for HD-FDD based on the signal format information, and performs puncturing on first several symbols to generate a PRACH signal. Further, the PDCCH signal demodulation · decoding section <NUM> and PHICH signal demodulation · decoding section <NUM> demodulate the PDCCH signal and PHICH signal assigned to first several symbols based on the signal format information, and further decode the signals.

In the transmission/reception in the same subframe, the transmission/reception channel · signal format selecting section <NUM> inputs the switch timing information to the switch 103c at a guard interval provided in the subframe. By this means, transmission of the uplink signal and reception of the downlink signal is switched in a single subframe.

As described above, according to the mobile terminal apparatus <NUM> according to this Embodiment, when transmission timing of an uplink signal and reception timing of a downlink signal overlaps each other in the mobile terminal apparatus, transmission/reception processing is performed selectively. Accordingly, for the mobile terminal apparatus <NUM> to which is applied HD-FDD, it is possible to cause the apparatus <NUM> to perform optimal operation when transmission timing of an uplink signal and reception timing of a downlink signal overlaps each other.

In addition, in the above-mentioned Embodiment, indication of a particular subframe is notified to the mobile terminal apparatus by RRC signaling or adding a control bit to the PDCCH signal, but is not limited thereto. The indication may be notified by any method, when the method enables the mobile terminal apparatus to be notified of the particular subframe.

Further, in the above-mentioned Embodiment, the priority relationship is set on the base station apparatus and the mobile terminal apparatus, and only the mobile terminal apparatus may be set for the priority relationship. Moreover, the priority relationship may be beforehand set on both the base station apparatus and the mobile terminal apparatus, may be notified from the base station apparatus to the mobile terminal apparatus, or may be notified from the mobile terminal apparatus to the base station apparatus.

Claim 1:
A terminal (<NUM>) configured to perform radio communications with a base station (<NUM>) by using a half-duplex scheme, comprising:
a control circuit configured to switch to transmitting, as an uplink signal, an uplink control signal or a random access channel signal within a subframe, after a given guard interval that is provided to prevent transmission of the uplink signal and reception of a downlink signal from overlapping each other within a subframe configured of a plurality of symbols, by using an uplink signal format for half-duplex frequency division duplex, HD-FDD, in which first several symbols are vacant in the subframe; the first several symbols being vacant in the subframe corresponding to the downlink signal and the guard interval; and
a transmission/reception circuit (<NUM>) configured to receive the downlink signal and transmit the uplink signal within the subframe,
wherein the control circuit is configured to control to receive a downlink control signal in symbols at the beginning of the first several symbols of the subframe, the downlink control signal being included in the downlink signal.