Patent Description:
In recent years, wireless communication applications have become more diverse with the proliferation and increase in performance of wireless communication terminal devices. In particular, transmitting high-definition video instantaneously requires instantaneous wireless transmission at a high peak rate, and wideband transmission (multiband transmission), which combines a plurality of different frequency bands, has been considered as a means to achieve this.

In multiband transmission, it is necessary to use a plurality of different frequency bands simultaneously in order to satisfy the required communication rate. In multiband transmission using a random access scheme as typified by wireless Local Area Network (LAN), a method of acquiring transmission rights for multiband transmission is conceivable in which transmission rights are acquired for each frequency band independently after a random standby time (backoff) has passed.

However, if the backoff for some frequency bands is relatively long, the standby time until the transmission rights for multiband transmission are acquired may increase. There has also been a risk of another wireless communication terminal device acquiring the transmission rights for such frequency bands where there is a long backoff. These issues may reduce opportunities to acquire transmission rights for multiband transmission in a random access scheme.

Accordingly, a method has been considered in which a transmission terminal device determines the frequency bands to be used for multiband transmission by sensing past communication traffic and predicting the availability of frequency bands immediately thereafter in order for the transmission terminal device to acquire transmission rights for multiband transmission (e.g., PTL <NUM>).

However, it has been difficult to implement this method due to limitations resulting from a need to synchronize the backoffs of different frequency bands within the transmission terminal device, the accuracy of predicting the availability information of the frequency bands depending on trends in the communication traffic, and the like.

Having been achieved in light of such a situation, the present disclosure is directed to suppress an increase in transmission standby times.

Hereinafter, modes for carrying out the present disclosure (hereinafter referred to as "embodiments") will be described. The descriptions will be given in the following order.

Accordingly, a method has been considered in which a transmission terminal device determines the frequency bands to be used for multiband transmission by sensing past communication traffic and predicting the availability of frequency bands immediately thereafter in order for the transmission terminal device to acquire transmission rights for multiband transmission, as described in PTL <NUM>, for example.

Accordingly, the wireless communication unit capable of wireless communication in a plurality of frequency bands is controlled to transmit a control signal in a second frequency band in which transmission is possible, the control signal being for wireless communication in a first frequency band. For example, a wireless communication device is provided with: a wireless communication unit capable of wireless communication in a plurality of frequency bands; and a control unit that controls the wireless communication unit to transmit a control signal in a second frequency band in which transmission is possible, the control signal being for wireless communication in a first frequency band. Additionally, for example, a program causes a computer to function as a control unit that controls the wireless communication unit capable of wireless communication in a plurality of frequency bands to transmit a control signal in a second frequency band in which transmission is possible, the control signal being for wireless communication in a first frequency band.

Doing so makes it possible to attempt to acquire transmission rights in a frequency band having a long backoff, using a frequency band in which transmission is possible. Accordingly, an increase in transmission standby time can be suppressed, even in a frequency band having a long backoff. This makes it possible to suppress a drop in opportunities to acquire transmission rights for multiband transmission in a random access scheme (typically, increase the opportunities to acquire transmission rights for multiband transmission).

Additionally, the wireless communication unit capable of wireless communication in a plurality of frequency bands is controlled to receive a control signal in a second frequency band in which reception is possible, the control signal being for wireless communication in a first frequency band. For example, a wireless communication device is provided with: a wireless communication unit capable of wireless communication in a plurality of frequency bands; and a control unit that controls the wireless communication unit to receive a control signal in a second frequency band in which reception is possible, the control signal being for wireless communication in a first frequency band. Additionally, for example, a program causes a computer to function as a control unit that controls the wireless communication unit capable of wireless communication in a plurality of frequency bands to receive a control signal in a second frequency band in which reception is possible, the control signal being for wireless communication in a first frequency band.

Doing so makes it possible to provide transmission rights in a frequency band having a long backoff, using a frequency band in which transmission is possible. Accordingly, an increase in transmission standby time can be suppressed, even in a frequency band having a long backoff. This makes it possible to suppress a drop in opportunities to acquire transmission rights for multiband transmission in a random access scheme (typically, increase the opportunities to acquire transmission rights for multiband transmission).

<FIG> is a block diagram illustrating an example of the main configuration of one aspect of a wireless communication system in which the present technique is applied. A wireless communication system <NUM> illustrated in <FIG> is a system that performs wireless communication, and is a system capable of performing wireless communication using a plurality of mutually-different frequency bands (also called multiband transmission). As illustrated in <FIG>, the wireless communication system <NUM> includes a base station (also referred to as "AP") <NUM> and a terminal device (also referred to as "STA") <NUM>. In the following, the present technique will be described using an example in which there is one each of the base station <NUM> and the terminal device <NUM>, but the wireless communication system <NUM> may be constituted by any number of base stations <NUM> and terminal devices <NUM>, with a plurality of each, different numbers of each, and so on. For example, the wireless communication system <NUM> may be constituted by one base station <NUM> and three terminal devices <NUM>. Or, for example, the wireless communication system <NUM> may be constituted by two base stations <NUM> and five terminal devices <NUM>.

The base station (AP) <NUM> and the terminal device (STA) <NUM> can communicate wirelessly with each other (and can exchange information with each other through this wireless communication). At this time, the base station <NUM> and the terminal device <NUM> can perform multiband transmission using a plurality of mutually-different frequency bands (e.g., Band <NUM> and Band <NUM>).

The configurations of the devices will be described next. <FIG> is a block diagram illustrating an example of the main configuration of the base station <NUM>. As illustrated in <FIG>, the base station <NUM> includes a control unit <NUM>, a power source unit <NUM>, a communication unit <NUM>, and a communication unit <NUM>.

The control unit <NUM> controls the power source unit <NUM>, as well as (a wireless control unit <NUM> of) the communication unit <NUM> and the communication unit <NUM>. Note that the control unit <NUM> may execute at least some of the operations of the wireless control unit <NUM> instead of the wireless control unit <NUM>.

The control unit <NUM> can have any desired configuration. For example, the control unit <NUM> may be configured as a logic circuit that implements the above-described processing. The control unit <NUM> may include, for example, a Central Processing Unit (CPU), Read Only Memory (ROM), Random Access Memory (RAM), and the like, and the above-described processing may be implemented by using these elements to execute a program. Of course, the control unit <NUM> may have both of these configurations, and some of the above-described processing may be implemented by a logic circuit, while other processing may be implemented by executing a program.

The power source unit <NUM> includes a battery power source or a fixed power source, and supplies power to the various units of the base station <NUM>. For example, the power source unit <NUM> supplies power to the various units within the base station <NUM> such that the control unit <NUM>, the wireless control unit <NUM>, or the like can execute processing in which the present technique is applied.

The communication unit <NUM> and the communication unit <NUM> each performs processing related to wireless communication. The communication unit <NUM> and the communication unit <NUM> can perform wireless communication in mutually-different frequency bands. The communication unit <NUM> and the communication unit <NUM> can also control each other and exchange information. The communication unit <NUM> and the communication unit <NUM> may be implemented through LSI (Large Scale Integration).

The communication unit <NUM> includes the wireless control unit <NUM>, a data processing unit <NUM>, a modulation/demodulation unit <NUM>, a signal processing unit <NUM>, a channel estimation unit <NUM>, a wireless interface unit <NUM>-<NUM> to a wireless interface unit <NUM>-N, an amplifier unit <NUM>-<NUM> to an amplifier unit <NUM>-N, and an antenna <NUM>-<NUM> to an antenna <NUM>-N (where N is any natural number). In the following, when there is no need to distinguish among the wireless interface unit <NUM>-<NUM> to the wireless interface unit <NUM>-N, the units will be referred to as a wireless interface unit <NUM>. Additionally, when there is no need to distinguish among the amplifier unit <NUM>-<NUM> to the amplifier unit <NUM>-N, the units will be referred to as an amplifier unit <NUM>. Additionally, when there is no need to distinguish among the antenna <NUM>-<NUM> to the antenna <NUM>-N, the antennas will be referred to as an antenna <NUM>. The wireless interface unit <NUM>, the amplifier unit <NUM>, and the antenna <NUM> are taken as a set, and one set is provided for each channel handled by the communication unit <NUM>.

The wireless control unit <NUM> can exchange information with each of the processing units in the communication unit <NUM>. Additionally, the wireless control unit <NUM> can set parameters to be used in the modulation/demodulation unit <NUM>, the signal processing unit <NUM>, and the like. The wireless control unit <NUM> can control the scheduling of processing on packets, performed in the data processing unit <NUM>. Additionally, the wireless control unit <NUM> can set parameters to be used in each wireless interface unit <NUM>. Additionally, the wireless control unit <NUM> can set parameters to be used in each amplifier unit <NUM>, each antenna <NUM>, and the like, control transmission power, and the like.

During transmission, when data is input from an upper layer, the data processing unit <NUM> generates packets for wireless transmission from the data, and performs processing such as adding headers for Media Access Control (MAC) and adding error detection code. The data processing unit <NUM> also supplies the processed data to the modulation/demodulation unit <NUM>. Conversely, during reception, when there is input from the modulation/demodulation unit <NUM>, the data processing unit <NUM> performs MAC header analysis, packet error detection, reordering processing, and the like, and supplies the processed data to the upper layer of the protocol of the data processing unit <NUM> itself.

During transmission, the modulation/demodulation unit <NUM> performs processing such as coding, interleaving, and modulation on the input data from the data processing unit <NUM> on the basis of a coding method and a modulation method set in, for example, the wireless control unit <NUM>, generates a data symbol stream, and supplies the stream to the signal processing unit <NUM>. During reception, the modulation/demodulation unit <NUM> performs the opposite processing as that performed during transmission on the input from the signal processing unit <NUM> (reverse processing), and supplies a result of that processing as data to the data processing unit <NUM> or the wireless control unit <NUM>.

During transmission, the signal processing unit <NUM> performs signal processing provided for spatial separation on the input from the modulation/demodulation unit <NUM> as necessary, and supplies the resulting one or more transmission symbol streams to the wireless interface unit <NUM> of each channel. During reception, the signal processing unit <NUM> performs signal processing on the reception symbol stream input from the wireless interface unit <NUM> of each channel, performs spatial separation of the stream as necessary, and supplies a result of the processing to the modulation/demodulation unit <NUM>.

The channel estimation unit <NUM> calculates complex channel gain information of a propagation path from a preamble part and a training signal part of the input signal from the wireless interface unit <NUM> of each channel. The channel estimation unit <NUM> supplies the calculated complex channel gain information to the modulation/demodulation unit <NUM>, the signal processing unit <NUM>, and the like via the wireless control unit <NUM>. The modulation/demodulation unit <NUM> uses the complex channel gain information for demodulation processing, for example. The signal processing unit <NUM> uses the complex channel gain information for spatial processing.

During transmission, the wireless interface unit <NUM> converts the input from the signal processing unit <NUM> into an analog signal, applies signal processing to the analog signal, such as filtering, up-conversion to a carrier frequency, and phase control, and supplies the processed analog signal to the antenna <NUM> or the amplifier unit <NUM> corresponding to the wireless interface unit <NUM> itself. During reception, the wireless interface unit <NUM> performs the opposite processing as that performed during transmission on the input from the antenna <NUM> or the amplifier unit <NUM> corresponding to the wireless interface unit <NUM> itself (reverse processing), and supplies the processed data to the signal processing unit <NUM> and the channel estimation unit <NUM>.

During transmission, the amplifier unit <NUM> amplifies the analog signal input from the wireless interface unit <NUM> corresponding to the amplifier unit <NUM> itself to a predetermined power. The amplifier unit <NUM> also transmits the amplified analog signal to the antenna <NUM> corresponding to the amplifier unit <NUM> itself. During reception, the amplifier unit <NUM> amplifies the analog signal received via the antenna <NUM> corresponding to the amplifier unit <NUM> itself to a predetermined power. The amplifier unit <NUM> supplies the amplified analog signal to the wireless interface unit <NUM> corresponding to the amplifier unit <NUM> itself.

Note that the communication unit <NUM> may have processing units aside from the above-described processing units. Additionally, some of the above-described processing units may be omitted. Additionally, the wireless interface unit <NUM>, the amplifier unit <NUM>, and the antenna <NUM> may be taken as one set, and one or more of those sets may serve as a constituent element of the communication unit <NUM>. Note also that the numbers of the wireless interface unit <NUM>, the amplifier unit <NUM>, and the antenna <NUM> may be the same as each other, or different. Additionally, the functions of the amplifier unit <NUM> may be partially or completely incorporated into the wireless interface unit <NUM>. For example, at least some of at least the functions of the amplifier unit <NUM> during transmission or the functions of the amplifier unit <NUM> during reception may be incorporated into the wireless interface unit <NUM>. Likewise, at least some of at least the functions of the amplifier unit <NUM> during transmission or the functions of the amplifier unit <NUM> during reception may be constituent elements outside the communication unit <NUM>.

The communication unit <NUM> has the same configuration as the communication unit <NUM> and performs the same processing. In other words, like the communication unit <NUM>, the communication unit <NUM> includes the wireless control unit <NUM>, the data processing unit <NUM>, the modulation/demodulation unit <NUM>, the signal processing unit <NUM>, the channel estimation unit <NUM>, the wireless interface unit <NUM>, the amplifier unit <NUM>, and the antenna <NUM> (where N is any natural number). The processing units of the communication unit <NUM>, from the wireless control unit <NUM> to the antenna <NUM>, perform the same processing as in the above-described communication unit <NUM>.

The communication unit <NUM> and the communication unit <NUM> may be separate constituent elements, or may share some constituent elements. For example, the wireless control unit <NUM> may be shared by the communication unit <NUM> and the communication unit <NUM>. The data processing unit <NUM> may be shared as well. The modulation/demodulation unit <NUM> may be shared as well.

As described above, the communication unit <NUM> and the communication unit <NUM> can perform wireless communication in mutually-different frequency bands. Accordingly, the base station <NUM> can communicate in a plurality of frequency bands using the communication unit <NUM> and the communication unit <NUM>, for example. In other words, the base station <NUM> is capable of multiband transmission.

Note that the base station <NUM> may include any number of communication units, and may have three or more, for example. In other words, the base station <NUM> may include a communication unit aside from the communication unit <NUM> and the communication unit <NUM>.

The following descriptions will assume, as an example, that the communication unit <NUM> performs wireless communication in a first frequency band (Band <NUM>), and the communication unit <NUM> performs wireless communication in a second frequency band (Band <NUM>).

The main configuration of the terminal device <NUM> is the same as the configuration of the base station <NUM> (<FIG>). It is therefore assumed that the descriptions of <FIG> can be applied to the terminal device <NUM> as well.

Conventionally, in communication using a plurality of frequency bands, the establishment of a session (acquisition of transmission rights) is performed independently for each frequency band, as illustrated in the example in <FIG>. The timing chart in <FIG> illustrates, in the top level, an example in which the base station (AP) <NUM> transmits data in the first frequency band (Band <NUM>). Additionally, this timing chart illustrates, in the second level from the top, an example in which the base station (AP) <NUM> transmits data in the second frequency band (Band <NUM>). Furthermore, this timing chart illustrates, in the third level from the top, an example in which the terminal device (STA) <NUM> transmits data in the first frequency band (Band <NUM>). Additionally, this timing chart illustrates, in the fourth level from the top, an example in which the terminal device (STA) <NUM> transmits data in the second frequency band (Band <NUM>).

In Band <NUM>, there is a period in which the terminal device (STA) determines that communication in Band <NUM> is not possible (Busy) due to interference power, communication between the base station (AP) <NUM> and other wireless communication devices, and the like. After the end of the Busy period, the terminal device (STA) <NUM> attempts to acquire transmission rights after a predetermined frame transmission interval (Arbitration Inter Frame Space (AIFS)) and a random standby time (Backoff). However, if the communication fails due to communication traffic congestion or the like, the terminal device <NUM> will provide a longer backoff on the basis of a random number. If, during this backoff period, the transmission to the base station (AP) <NUM> is interrupted by another wireless communication device, the terminal device (STA) <NUM> will shift to the Busy state again. Accordingly, it may become difficult for the terminal device (STA) <NUM> to get an opportunity to communicate with the base station (AP) <NUM> in Band <NUM>.

On the other hand, if no interference power, communication between the base station (AP) <NUM> and another wireless communication device, or the like is observed in Band <NUM>, the terminal device (STA) <NUM> is likely to get an opportunity to communicate with the base station (AP) <NUM> in that Band <NUM>.

In the case of the conventional method of obtaining transmission rights independently for each frequency band as illustrated in the example in <FIG>, opportunities to execute multiband transmission may be very limited because the terminal device (STA) <NUM> can only perform multiband transmission using two such frequency bands after the end of the long backoff provided for Band <NUM>. There has therefore been a risk of a drop in the efficiency of data transmission.

Accordingly, Band <NUM>, which is available for transmission, is used to acquire transmission rights for the other frequency band, which is Band <NUM> (as well as for Band <NUM>).

In order to perform multiband transmission, the base station <NUM> and the terminal device <NUM> of the wireless communication system <NUM> perform multiband transmission processing. An example of the overall flow of the multiband transmission processing will be described with reference to the flowchart in <FIG>.

As illustrated in <FIG>, the multiband transmission processing is constituted by four phases, namely Capability Exchange (step S101), Association (step S102), MB (Multi Band) Configuration (step S103), and Data Transmitting (step S104). The order in which the phases are executed is not limited to the example in <FIG>. For example, the Capability Exchange may be performed after the Association.

In the Capability Exchange in step S101, the base station (AP) <NUM> and the terminal device (STA) <NUM> exchange information about the functions the respective devices can execute (also called "capability information"). By exchanging the capability information, the base station <NUM> and the terminal device <NUM> notify each other as to whether they are able to execute MB Configuration.

In the Association in step S102, the base station (AP) <NUM> and the terminal device (STA) <NUM> complete connection processing between the base station <NUM> and the terminal device <NUM>.

In the MB Configuration in step S103, the base station (AP) <NUM> and the terminal device (STA) <NUM> determine which frequency band and which frequency bandwidth will be used for multiband transmission before the Data Transmission.

In the Data Transmission in step S104, the base station (AP) <NUM> and the terminal device (STA) <NUM> perform multiband transmission using the frequency band and frequency bandwidth determined in the MB Configuration (step S103).

In the MB Configuration of step S103 of the multiband transmission processing described above, the terminal device <NUM> transmits an MB Request (also called "MB Req"), which is a control signal for performing wireless communication in the first frequency band, in the second frequency band in which transmission is possible, and the base station <NUM> receives the MB Request (step S111). Then, in the case of the present embodiment, the base station (AP) <NUM> serves as the main entity that determines the frequency band and frequency bandwidth to be used during multiband transmission (step S112). After determining the frequency band and frequency bandwidth to be used for multiband transmission on the basis of the MB Request, the base station <NUM> transmits an MB Polling (also called "MB Poll"), which is a response signal to the MB Request, to the terminal device <NUM>, and the terminal device <NUM> receives the MB Polling (step S113). By exchanging this MB Polling, the frequency band and frequency bandwidth determined by the base station <NUM> are communicated to the terminal device <NUM>. The base station <NUM> and the terminal device <NUM> can therefore perform multiband transmission with the determined frequency band and frequency bandwidth in the Data Transmission (step S104).

In the Capability Exchange (step S101), the base station <NUM> and the terminal device <NUM> exchange capability information with each other. <FIG> illustrates an example of the main configuration of a frame of this capability information (also called a "capability frame").

As illustrated in <FIG>, a capability frame <NUM> includes, for example, MBO (Multi Band Operation) Capabilities <NUM>, which indicates performance related to multiband transmission. This MBO Capabilities <NUM> includes, for example, a Flag <NUM> and A-Bandwidth <NUM>.

The Flag <NUM> holds flag information indicating whether or not the wireless communication device that transmitted the capability frame <NUM> (e.g., the base station <NUM>, the terminal device <NUM>, or the like) is capable of executing the MB Configuration. If the Flag <NUM> indicates that the MB Configuration can be executed, the Flag <NUM> may also include information related to other information in the MBO Capabilities <NUM>. For example, information indicating how many bits the A-Bandwidth <NUM> is expressed with may be included in the Flag <NUM>.

The A-Bandwidth <NUM> includes information indicating the frequency band and frequency bandwidth that the wireless communication device which transmitted the capability frame <NUM> (e.g., the base station <NUM>, the terminal device <NUM>, or the like) can use during multiband transmission (i.e., information pertaining to candidates for the frequency band and frequency bandwidth). Note that if the Flag <NUM> includes information indicating that the MB Configuration cannot be executed, the A-Bandwidth <NUM> may be omitted.

A sequence of the MB Configuration (step S103) will be described next. <FIG> is a timing chart illustrating an example of the MB Configuration performed during multiband transmission.

In the example illustrated in <FIG>, in a state in which transmission is possible, where the backoff in the second frequency band (Band <NUM>) has ended and transmission rights have been acquired, and where the first frequency band (Band <NUM>) is in a state which does not correspond to data being transmitted or Busy (an Idle state), the terminal device (STA) <NUM> transmits an MB Request (MB Req) in the second frequency band (Band <NUM>).

The MB Req is a control signal for wireless communication in the second frequency band, in which the terminal device (STA) <NUM> is capable of transmitting the MB Req in the Data Transmission, and the first frequency band (a control signal requesting the implementation of wireless communication in another frequency band). For example, this MB Req is transmitted to perform transmission in the first frequency band which is in an Idle state.

For example, the MB Req is transmitted to implement multiband transmission (synchronized transmission in at least two or more frequency bands among a plurality of frequency bands including the first frequency band and the second frequency band) (to request the implementation of multiband transmission). This MB Req includes, for example, information requesting a notification of the frequency band and frequency bandwidth that can be used for the multiband transmission. Note that this MB Req may include information indicating the frequency band and frequency bandwidth that the terminal device (STA) <NUM> uses preferentially. This MB Req may also include information about a period during which the base station <NUM> and the terminal device <NUM> communicate in at least one frequency band, and a period during which a third device that receives this MB Req suppresses transmission. The terminal device <NUM> transmits this MB Req to the base station <NUM> using Band <NUM>, in which transmission is possible. Multiband transmission is a data transmission that uses a plurality of frequency bands, as described above.

When the MB Req is received, the base station <NUM> transmits the MB Polling (MB Poll) as a response signal in Band <NUM> and Band <NUM>. This MB Poll includes, for example, information indicating the frequency band and frequency bandwidth used by the terminal device (STA) <NUM> for multiband transmission in the Data Transmission. This MB Poll may also include information about a period during which the base station <NUM> and the terminal device <NUM> communicate in at least one frequency band, and a period during which a third device that receives this MB Req suppresses transmission. Note that the information about the period may be information recalculated from the information about the period communicated by the MB Req.

Note also that this MB Poll can be transmitted in any frequency band. For example, the base station <NUM> may transmit the MB Poll in all or some of the frequency bands in which the base station <NUM> is capable of transmission. Additionally, for example, the base station <NUM> may transmit the MB Poll in all or some of the frequency bands in which the terminal device <NUM> is capable of reception, which are known from the exchange of the capability information. Furthermore, for example, the base station <NUM> may transmit the MB Poll in all or some of the frequency bands that the terminal device <NUM> can use for multiband transmission, indicated by the MB Req. Additionally, for example, the base station <NUM> may transmit the MB Poll in all or some of the frequency bands that the terminal device <NUM> uses preferentially, indicated by the MB Req. Furthermore, for example, the base station <NUM> may transmit the MB Poll in all or some of the frequency bands determined to be used in the multiband transmission.

In other words, the base station <NUM> may transmit the MB Poll in a single frequency band, or may transmit the MB Poll in a plurality of frequency bands. By having the base station <NUM> transmit the MB Poll in a plurality of frequency bands, the terminal device <NUM> can more reliably receive the MB Poll transmitted by the base station <NUM>.

In the Data Transmission, the terminal device <NUM> and the base station <NUM> perform multiband transmission using the frequency band and frequency bandwidth specified by this MB Poll, i.e., the frequency band and frequency bandwidth determined by the base station <NUM>.

However, if the MB Poll indicates that multiband transmission is not possible, the terminal device <NUM> and the base station <NUM> may perform wireless communication in a single frequency band without performing multiband transmission.

Note that in the example in <FIG>, the terminal device (STA) <NUM> is illustrated as transmitting the MB Request using Band <NUM>, but the configuration is not limited thereto, and the terminal device <NUM> can also transmit the MB Request using Band <NUM>. For example, if the transmission rights can be acquired in Band <NUM> before Band <NUM>, the terminal device <NUM> may use Band <NUM> to transmit the MB Request. Additionally, for example, if the transmission rights have been successfully acquired simultaneously in both Band <NUM> and Band <NUM>, the terminal device <NUM> may transmit the MB Request using both Band <NUM> and Band <NUM>, or the transmission of the MB Request (i.e., MB Configuration) may be omitted (with the Data Transmission being performed without the MB Configuration).

Although the example of <FIG> illustrates a case where two frequency bands, Band <NUM> and Band <NUM>, are used for multiband transmission, the configuration is not limited thereto, and three or more frequency bands may be used for this multiband transmission.

The configuration of the frame of the above-described MB Req will be described next. <FIG> is a diagram illustrating an example of the main configuration of the MB Req frame. As illustrated in <FIG>, an MB Req frame <NUM> includes, for example, Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, TA <NUM>, and MBO Control <NUM>.

Frame Control <NUM> includes information indicating that the frame is an MB Request. Note that Frame Control <NUM> may include information indicating that MBO Control <NUM> is present in the frame. In other words, MBO Control <NUM> can be omitted. Frame Control <NUM> may also include information indicating the length of MBO Control <NUM>.

Duration/ID <NUM> includes information indicating the length of the frame. RA <NUM> includes information indicating that the frame is intended to be received by the base station (AP) <NUM>. This information includes, for example, a MAC (Media Access Control) address indicating the base station (AP) <NUM>. TA <NUM> includes information indicating that the frame was transmitted by the terminal device (STA) <NUM>. This information includes, for example, a MAC address indicating the terminal device (STA) <NUM>.

MBO Control <NUM> is the control information pertaining to multiband transmission. This MBO Control <NUM> according to the invention includes information indicating candidates for the frequency bands and optionally frequency bandwidths to be used in the multiband transmissions, together with the priorities thereof. For example, this MBO Control <NUM> includes Multi Band List <NUM> and Priority Order <NUM>.

Multi Band List <NUM> includes information indicating the frequency bands and frequency bandwidths that the terminal device (STA) <NUM> can use for multiband transmission (i.e., candidates for the frequency bands and frequency bandwidths to be used for multiband transmission). This Multi Band List <NUM> may include information indicating the frequency band and frequency bandwidth that the terminal device (STA) <NUM> will preferentially use for multiband transmission.

Priority Order <NUM> includes information pertaining to the priority of the candidates for the frequency bands and frequency bandwidths indicated in Multi Band List <NUM>. For example, Priority Order <NUM> may include information indicating a priority order of the candidates for the frequency bands and frequency bandwidths, indicated in Multi Band List <NUM>, that the terminal device (STA) <NUM> will use for multiband transmission in the Data Transmission.

Note that Multi Band List <NUM> and Priority Order <NUM> do not have to be stored in the order indicated in <FIG>. For example, if information indicating a plurality of frequency bands and frequency bandwidths can be stored in Multi Band List <NUM>, information indicating a priority order of the information may be stored immediately after the information indicating each frequency band and frequency bandwidth.

The configuration of the frame of above-described MB Poll will be described next. <FIG> is a diagram illustrating an example of the main configuration of the MB Poll frame. As illustrated in <FIG>, an MB Poll frame <NUM> includes, for example, Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, TA <NUM>, and MBO Band <NUM>.

Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, and TA <NUM> are the same as Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, and TA <NUM>, respectively, of the MB Req frame.

For example, Frame Control <NUM> includes information indicating that the frame is an MB Poll. Note that Frame Control <NUM> may include information indicating that MBO Band <NUM> is present in the frame. Frame Control <NUM> may also include information indicating the length of MBO Band <NUM>.

Duration/ID <NUM> includes information indicating the length of the frame. RA <NUM> includes information indicating that the frame is intended to be received by the terminal device (STA) <NUM>. This information includes, for example, a MAC address indicating the terminal device (STA) <NUM>. TA <NUM> includes information indicating that the frame was transmitted by the base station (AP) <NUM>. This information includes, for example, a MAC address indicating the base station (AP) <NUM>.

MBO Band <NUM> includes information indicating the frequency band and frequency bandwidth to be used for multiband transmission in the Data Transmission, which has been determined by the base station <NUM>. Note that if multiband transmission is not possible, this MBO Band <NUM> may include information indicating that multiband transmission is not possible.

In the MB Configuration (step S103), the terminal device (STA) <NUM> executes the MB configuration processing and performs the above-described processing. An example of the flow of the MB configuration processing by the terminal device <NUM> will be described with reference to the flowchart in <FIG>.

When the MB configuration processing is started, in step S201, the control unit <NUM> of the terminal device <NUM> refers to the capability information of the base station (AP) <NUM> obtained in the Capability Exchange (step S101) phase, and determines whether or not MB Configuration is indicated as being possible by Flag <NUM> of MBO Capabilities <NUM> in the capability frame <NUM>.

If the information indicating that the base station <NUM> can execute the MB configuration is included in the Flag <NUM>, and it is determined that the base station <NUM> is capable of executing the MB Configuration, the processing moves to step S202.

In step S202, the control unit <NUM> determines whether or not there is a frequency band in which the backoff has ended. If it is determined that there is no such frequency band, the processing moves to step S203.

In step S203, the control unit <NUM> stands by until the backoff ends. When the processing of step S203 ends, the processing moves to step S204. If it is determined in step S202 that there is a frequency band in which the backoff has ended, the processing of step S203 is skipped, and the processing moves to step S204.

In step S204, the control unit <NUM> determines whether or not a plurality of frequency bands among the frequency bands in which the terminal device <NUM> is capable of multiband transmission are idle. The Idle state is a state that is neither a state in which data transmission is underway, nor a busy state. For example, a state in which no data transmission is being performed, between the busy state and a state in which data transmission is underway, is also called an Idle state. In other words, when the backoff ends in one of the frequency bands, the control unit <NUM> determines whether there is another frequency band that is in the Idle state.

Any method can be used to determine whether or not the state is the Idle state. For example, the state may be determined to be the Idle state when none of the following three conditions ((<NUM>) to (<NUM>)) are met.

If it is determined that a plurality of frequency bands are in the Idle state, i.e., when the backoff ends for one of the frequency bands, there is another frequency band in the Idle state, the processing moves to step S205.

In step S205, the control unit <NUM> controls the communication unit <NUM> or the communication unit <NUM> to acquire transmission rights in the frequency band in which the backoff has ended (Band <NUM>, in the case of the example in <FIG>), and to transmit the MB Request for multiband transmission to the base station <NUM> using that frequency band (Band <NUM>, in the case of the example in <FIG>). In other words, the control unit <NUM> causes the control signal for wireless communication in the first frequency band to be transmitted in the second frequency band, which is capable of transmission.

The MB Polling is transmitted from the base station <NUM> as a response signal to the MB Request transmitted in this manner. The communication unit <NUM>, the communication unit <NUM>, or both receive this MB Polling. In step S206, the control unit <NUM> determines whether or not the communication unit <NUM>, the communication unit <NUM>, or both have received the MB Polling in any of the frequency bands from the base station <NUM>.

The processing moves to step S207 if it is determined that the MB Polling has not been received in any of the frequency bands. In step S207, the control unit <NUM> determines whether or not to make a retransmission request for the MB Polling. The processing moves to step S208 when it is determined to make a retransmission request. In step S208, the control unit <NUM> controls the communication unit <NUM>, the communication unit <NUM>, or both to request the base station <NUM> to retransmit the MB Polling. Once the processing of step S208 ends, the processing returns to step S206, and the processing following thereafter is repeated. This retransmission request is repeated a predetermined number of times or for a predetermined period if no MB Polling is received.

Then, in step S206, if it is determined that the MB Polling has been received in any of the frequency bands, the processing moves to step S209.

In step S209, the control unit <NUM> refers to the MB Polling received by the communication unit <NUM>, the communication unit <NUM>, or both, and sets the frequency band/frequency bandwidth indicated in MBO Band <NUM> of MB Poll frame <NUM> thereof (the frequency band/frequency bandwidth determined by the base station <NUM>) as the frequency band/frequency bandwidth to be used for multiband transmission.

As described above, by setting the frequency band/frequency bandwidth to be used for multiband transmission, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, multiband transmission is performed in the Data Transmission.

Note that when the received MB Polling indicates that multiband transmission is not possible, the processing of step S210, described later, may be executed instead of the above-described processing of step S209.

Additionally, in step S201, if the information indicating that the base station <NUM> cannot execute the MB configuration is included in the Flag <NUM>, and it is determined that the base station <NUM> is capable of executing the MB Configuration, the processing moves to step S210. Additionally, in step S204, if it is determined that the plurality of frequency bands are not in the Idle state and multiband transmission cannot be performed, the processing moves to step S210. Additionally, in step S207, if the MB Polling retransmission request is repeated a predetermined number of times or for a predetermined period and it is determined that no further MB Polling retransmission requests are to be made, the processing moves to step S210.

In other words, in these cases, the control unit <NUM> gives up on the multiband transmission, and transmits the data using a single frequency band in which data can be transmitted (also called "single-band transmission"). In other words, in step S210, the control unit <NUM> controls the communication unit <NUM> or the communication unit <NUM>, and sets the frequency band/frequency bandwidth for which the backoff has ended as the frequency band/frequency bandwidth to be used for data transmission (single-band transmission). In other words, in this case, the control unit <NUM> obtains the transmission rights independently for each frequency band.

Once the processing of step S210 ends, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, single-band transmission is performed in the Data Transmission.

Although the foregoing describes the control unit <NUM> as performing the MB configuration processing, the configuration is not limited thereto, and any of the wireless control units <NUM> may perform the MB configuration processing, a plurality of the wireless control units <NUM> may perform the MB configuration processing cooperatively, or the control unit <NUM> and the wireless control unit <NUM> may perform the MB configuration processing cooperatively.

In the MB Configuration (step S103), the base station (AP) <NUM> executes the MB configuration processing and performs the above-described processing in response to the MB configuration processing by the terminal device (STA) <NUM> described above. An example of the flow of the MB configuration processing by the base station <NUM> will be described with reference to the flowchart in <FIG>.

When the MB configuration processing is started, in step S251, the control unit <NUM> of the base station <NUM> controls the communication unit <NUM> or the communication unit <NUM> and receives the MB Request, transmitted from the terminal device <NUM>, in any of the frequency bands in which reception is possible.

In step S252, the control unit <NUM> determines whether or not there is a frequency band in the Idle state aside from the frequency band in which the MB Request was received. Any method can be used to determine whether or not the state is the Idle state. For example, the state may be determined to be the Idle state when none of the three conditions ((<NUM>) to (<NUM>)) described above in <MB Configuration Processing by Terminal Device> are met. When it is determined that there is a frequency band in the Idle state, the processing moves to step S253.

In step S253, the control unit <NUM> determines the frequency band/frequency bandwidth to be used for multiband transmission, and stores information indicating the determined frequency band/frequency bandwidth in MBO Band <NUM> of the MB Poll frame <NUM>. In other words, the control unit <NUM> determines a frequency band/frequency bandwidth which the control unit <NUM> itself can use for multiband transmission, from among the candidates for the frequency band/frequency bandwidth indicated in the received MB Request (frequency bands/frequency bandwidths which the terminal device <NUM> can use for multiband transmission), as the frequency band/frequency bandwidth to be used for the multiband transmission.

Note that when there are a plurality of frequency bands/frequency bandwidths which the base station <NUM> and the terminal device <NUM> can use for the multiband transmission, the control unit <NUM> may determine the frequency band/frequency bandwidth to be used for the multiband transmission on the basis of the priority (priority order) indicated by the MB Request, for example. The processing moves to step S255 when the MB Polling is generated as described above.

Additionally, in step S252, if it is determined that there is no other frequency band in the Idle state, the processing moves to step S254. In step S254, the control unit <NUM> determines to transmit data in the frequency band in which the MB Request was received, and stores that information in MBO Band <NUM> of the MB Poll frame <NUM>. In other words, the control unit <NUM> determines not to perform multiband transmission, and stores information indicating that data is to be transmitted in the frequency band in which the MB Request was received (or information indicating that multiband transmission is not possible) in MBO Band <NUM> of the MB Poll frame <NUM>. The processing moves to step S255 when the MB Polling is generated as described above.

In step S255, the control unit <NUM> controls the communication unit <NUM>, the communication unit <NUM>, or both to transmit the MB Polling generated in step S253 or step S254 to the terminal device <NUM> as a response signal to the MB Request. As described above with reference to <FIG>, this MB Polling can be transmitted in any frequency band.

Once the MB Polling is transmitted in this manner, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, multiband transmission or single-band transmission is performed in the Data Transmission. For example, if the MB Polling has been generated through the processing of step S253, multiband transmission is performed in the Data Transmission. Alternatively, if the MB Polling has been generated through the processing of step S254, single-band transmission is performed in the Data Transmission.

As described above, the terminal device <NUM>, which can perform multiband transmission, uses the MB Request to notify the base station <NUM> of transmission in two or more frequency bands, using the band through which the transmission rights were acquired first. Through this, the base station <NUM> can determine the frequency band to be used for the multiband transmission on the basis of that MB Request, and notify the terminal device <NUM> thereof as the MB Polling. Accordingly, the terminal device <NUM> can shift a frequency band which is in an Idle state (a standby state) to a state in which transmission is possible immediately on the basis of the MB Polling transmitted from the base station <NUM>. This makes it possible for the terminal device <NUM> to suppress an increase in the transmission standby time caused by multiband transmission.

Additionally, by shortening this transmission standby time, the terminal device <NUM> can suppress a drop in the opportunities to acquire the transmission rights for multiband transmission in a random access scheme. Furthermore, by transmitting the MB Request using the frequency band for which transmission rights have already been acquired, the terminal device <NUM> can suppress the occurrence of collisions caused by transmitting the MB Request. Additionally, by transmitting the MB Poll, the terminal device <NUM> can suppress the occurrence of collisions caused by other communication when receiving data, even if the back-off time is reduced. Accordingly, a drop in the efficiency of frequency band usage by wireless communication can be suppressed (or more typically, the efficiency of usage can be improved) for the entire wireless communication system <NUM>.

Note that when the base station <NUM> transmits the same MB Polling in a plurality of frequency bands, a diversity effect in those frequency bands can be obtained. This makes it possible to suppress a drop in the probability that the terminal device <NUM> will receive that MB Polling (or more typically, improve that probability).

Although the first embodiment described the base station (AP) <NUM> as being the main entity that determines the frequency band and frequency bandwidth used in the multiband transmission, the configuration is not limited thereto, and the terminal device (STA) <NUM> may be the main entity that determines the frequency band and the frequency bandwidth used in the multiband transmission.

An example of the overall flow of the multiband transmission processing in this case will be described with reference to the flowchart in <FIG>. In this case too, the multiband transmission processing is constituted by four phases, namely Capability Exchange (step S101), Association (step S102), MB (Multi Band) Configuration (step S103), and Data Transmitting (step S104).

However, in the present embodiment, the terminal device <NUM> serves as the main entity that determines the frequency band and frequency bandwidth to be used in the multiband transmission in the MB Configuration of step S103.

For example, using a frequency band in which transmission is possible, the terminal device <NUM> transmits an MB Request-I (also called "MB Req-I"), which is a control signal for performing wireless communication in another frequency band, and the base station <NUM> receives that MB Request-I (step S301). Then, in the present embodiment, the base station <NUM> transmits an MB Announcement (also called "MB Info") as a response signal to the MB Request-I, and the terminal device <NUM> receives that MB Announcement (step S302). The MB Announcement includes information indicates candidates for the frequency band and frequency bandwidth that can be used during multiband transmission.

The terminal device <NUM> determines the frequency band and frequency bandwidth to be used during multiband transmission on the basis of that MB Announcement (step S303). In other words, the terminal device <NUM> selects the frequency band and frequency bandwidth to be used during multiband transmission from among the candidates included in that MB Announcement.

The base station <NUM> and the terminal device <NUM> perform multiband transmission with the determined frequency band and frequency bandwidth in the Data Transmission (step S104).

<FIG> illustrates an example of the main configuration of the frame of the capability information exchanged between the base station <NUM> and the terminal device <NUM> in the Capability Exchange (step S101) in the present embodiment.

In the present embodiment, a capability frame <NUM> includes, for example, MBO (Multi Band Operation) Capabilities <NUM>, which indicates performance related to multiband transmission. This MBO Capabilities <NUM> includes, for example, a Flag-I <NUM> and A-Bandwidth <NUM>.

Like the Flag <NUM>, the Flag-I <NUM> holds flag information indicating whether or not the wireless communication device that transmitted the capability frame <NUM> (e.g., the base station <NUM>, the terminal device <NUM>, or the like) is capable of executing the MB Configuration. If the Flag-I <NUM> indicates that the MB Configuration can be executed, the Flag-I <NUM> may also include information related to other information in the MBO Capabilities <NUM>. For example, information indicating how many bits the A-Bandwidth <NUM> is expressed with may be included in the Flag-I <NUM>.

Like the A-Bandwidth <NUM>, the A-Bandwidth <NUM> includes information indicating the frequency band and frequency bandwidth that the wireless communication device which transmitted the capability frame <NUM> (e.g., the base station <NUM>, the terminal device <NUM>, or the like) can use during multiband transmission (i.e., information pertaining to candidates for the frequency band and frequency bandwidth). Note that if the Flag-I <NUM> includes information indicating that the MB Configuration cannot be executed, the A-Bandwidth <NUM> may be omitted.

A sequence of the MB Configuration (step S103) will be described next. <FIG> is a timing chart illustrating an example of the MB Configuration performed during multiband transmission in the present embodiment.

As in the first embodiment, in the example illustrated in <FIG>, in a state where the backoff in the second frequency band (Band <NUM>) has ended and transmission rights have been successfully acquired, and where the first frequency band (Band <NUM>) is in a state which does not correspond to data being transmitted or Busy (an Idle state), the terminal device (STA) <NUM> transmits the MB Request-I (MB Req-I) in Band <NUM>.

The MB Req-I is a control signal for the terminal device (STA) <NUM> to perform wireless communication, in the Data Transmission, in another frequency band aside from the frequency band in which the MB Req-I can be sent (a control signal requesting wireless communication in the other frequency band). For example, this MB Req-I is transmitted to perform transmission in another frequency band which is in an Idle state.

For example, the MB Req-I is transmitted in order to perform multiband transmission (synchronized transmission in a plurality of frequency bands) (i.e., is transmitted to request multiband transmission). In other words, the MB Req-I is a control signal requesting that the terminal device <NUM> transmit the MB Info, which is a response signal thereto.

Note that this MB Req-I may include reference information for narrowing the range of information communicated through the MB Info. For example, information indicating a range of candidates for the frequency band and frequency bandwidth to be used in multiband transmission (or more candidates) may be included. For example, the MB Req-I may include information indicating a frequency band and frequency bandwidth the terminal device <NUM> can use for multiband transmission. Additionally, for example, information indicating the frequency band and frequency bandwidth that the terminal device <NUM> uses preferentially (information indicating priority) may be included. In addition, this MB Req-I may also include information about a period during which the base station <NUM> and the terminal device <NUM> communicate in at least one frequency band, and a period during which a third device that receives this MB Req-I suppresses transmission.

Announcement (MB Info) to the terminal device <NUM> as a response signal in Band <NUM> and Band <NUM>. This MB Info includes information indicating the frequency band and frequency bandwidth determined to be usable for multiband transmission in the Data Transmission by the base station <NUM> at the point in time when the MB Req-I was received, for example. This MB Info may also include information about a period during which the base station <NUM> and the terminal device <NUM> communicate in at least one frequency band, and a period during which a third device that receives this MB Req suppresses transmission. Note that the information about the period may be information recalculated from the information about the period communicated by the MB Req-I.

In other words, upon receiving the MB Req-I, the base station <NUM> sets candidates for the frequency band and frequency bandwidth to be used in the multiband transmission, generates the MB Info including information indicating the set candidates, and transmits the MB Info to the terminal device <NUM>, for example. At this time, the base station <NUM> may select a frequency band and frequency bandwidth the base station <NUM> can use for multiband transmission from the information included in the MB Req-I (e.g., the frequency bands and frequency bandwidths the terminal device <NUM> can use for multiband transmission), and set the selected frequency band and frequency bandwidth as the candidates for the frequency band and frequency bandwidth to be used for multiband transmission. Doing so makes it possible for the base station <NUM> to take a frequency band and frequency bandwidth usable by both the base station <NUM> and the terminal device <NUM> as the candidates. Additionally, for example, the base station <NUM> may set the above-described candidates on the basis of information, included in the MB Req-I, indicating a frequency band and frequency bandwidth used preferentially by the terminal device <NUM>. Doing so makes it possible for the base station <NUM> to set the above-described candidates in consideration of the priorities of the frequency band and frequency bandwidth.

Note also that this MB Info can be transmitted in any frequency band. For example, the base station <NUM> may transmit the MB Info in all or some of the frequency bands in which the base station <NUM> is capable of transmission. Additionally, for example, the base station <NUM> may transmit the MB Info in all or some of the frequency bands in which the terminal device <NUM> is capable of reception, which are known from the exchange of the capability information. Furthermore, for example, the base station <NUM> may transmit the MB Info in all or some of the frequency bands that the terminal device <NUM> can use for multiband transmission, indicated by the MB Req-I. Additionally, for example, the base station <NUM> may transmit the MB Info in all or some of the frequency bands that the terminal device <NUM> uses preferentially, indicated by the MB Req-I. Furthermore, for example, the base station <NUM> may transmit the MB Info in all or some of the candidate frequency bands which have been set.

In other words, the base station <NUM> may transmit the MB Info in a single frequency band, or may transmit the MB Info in a plurality of frequency bands. By having the base station <NUM> transmit the MB Info in a plurality of frequency bands, the terminal device <NUM> can more reliably receive the MB Info transmitted by the base station <NUM>.

Upon receiving the MB Info, the terminal device <NUM> determines the frequency band and frequency bandwidth to be used for multiband transmission on the basis of the information included in the MB Info. For example, the terminal device <NUM> selects the frequency band and frequency bandwidth to be used for multiband transmission from among the candidates specified by the MB Info.

The terminal device <NUM> and the base station <NUM> perform multiband transmission using the frequency band and frequency bandwidth determined by the terminal device <NUM> in the Data Transmission.

However, if the MB Info indicates that multiband transmission is not possible, the terminal device <NUM> and the base station <NUM> may perform wireless communication in a single frequency band without performing multiband transmission.

Like the first embodiment, in the present embodiment, the terminal device <NUM> can also transmit the MB Request-I using Band <NUM>. For example, if the transmission rights can be acquired in Band <NUM> before Band <NUM>, the terminal device <NUM> may use Band <NUM> to transmit the MB Request-I. Additionally, for example, if the transmission rights have been successfully acquired simultaneously in both Band <NUM> and Band <NUM>, the terminal device <NUM> may transmit the MB Request-I using both Band <NUM> and Band <NUM>, or the transmission of the MB Request-I (i.e., MB Configuration) may be omitted (with the Data Transmission being performed without the MB Configuration).

Additionally, like the first embodiment, in the present embodiment, three or more frequency bands may be used for this multiband transmission.

The configuration of the frame of above-described MB Req-I will be described next. <FIG> is a diagram illustrating an example of the main configuration of the MB Req-I frame. As illustrated in <FIG>, like the MB Req frame <NUM>, an MB Req-I frame <NUM> includes, for example, Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, TA <NUM>, and MBO Control <NUM>.

Frame Control <NUM> includes information indicating that the frame is an MB Request-I. Note that Frame Control <NUM> may include information pertaining to MBO Control <NUM>. For example, Frame Control <NUM> may include information indicating the presence or absence of MBO Control <NUM>. In other words, MBO Control <NUM> can be omitted. Frame Control <NUM> may also include information indicating the length of MBO Control <NUM>.

Duration/ID <NUM> to TA <NUM> are basically the same as Duration/ID <NUM> to TA <NUM>, respectively.

For example, Duration/ID <NUM> includes information indicating the length of the frame. RA <NUM> includes information indicating that the frame is intended to be received by the base station (AP) <NUM>. This information includes, for example, a MAC address indicating the base station <NUM>. TA <NUM> includes information indicating that the frame was transmitted by the terminal device (STA) <NUM>. This information includes, for example, a MAC address indicating the terminal device <NUM>.

MBO Control <NUM> includes information for limiting the candidates for the frequency band and frequency bandwidth during multiband transmission, communicated by the MB Info. According to the invention, this MBO Control <NUM> includes information indicating the candidates for the frequency band and optionally frequency bandwidth to be used in multiband transmission (or a range of possible values). For example, information indicating a frequency band and frequency bandwidth the terminal device <NUM> can use for multiband transmission may be included as the information indicating the candidates. Additionally, according to the invention, information indicating the frequency band and frequency bandwidth that the terminal device <NUM> uses preferentially (information indicating a priority of each candidate) is included.

For example, this MBO Control <NUM> includes Multi Band List <NUM> and Priority Order <NUM>. The Multi Band List <NUM> includes information indicating a frequency band and frequency bandwidth which may be communicated by the MB Info. In other words, the Multi Band List <NUM> may include information indicating the candidates for the frequency band and frequency bandwidth to be used in multiband transmission (or a range of possible values), such as that described above.

Priority Order <NUM> includes information pertaining to the priority of the candidates for the frequency bands and frequency bandwidths used in multiband transmission as described above, indicated in Multi Band List <NUM>. For example, Priority Order <NUM> may include information indicating a priority order of the candidates indicated by Multi Band List <NUM>.

The configuration of the frame of above-described MB Info will be described next. <FIG> is a diagram illustrating an example of the main configuration of an MB Info frame. As illustrated in <FIG>, like the MB Poll frame <NUM>, an MB Info frame <NUM> includes, for example, Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, TA <NUM>, and MBO Band Info <NUM>.

Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, and TA <NUM> are the same as Frame Control <NUM>, Duration/ID <NUM>, RA <NUM>, and TA <NUM>, respectively, of the MB Req-I frame <NUM>.

For example, Frame Control <NUM> includes information indicating that the frame is an MB Info. Note that Frame Control <NUM> may include information pertaining to the MBO Band Info <NUM>. For example, Frame Control <NUM> may include information indicating that the MBO Band Info <NUM> is present in the frame. Frame Control <NUM> may also include information indicating the length of the MBO Band Info <NUM>.

Duration/ID <NUM> includes information indicating the length of the frame. RA <NUM> includes information indicating that the frame is intended to be received by the terminal device (STA) <NUM>. This information includes, for example, a MAC address indicating the terminal device <NUM>. TA <NUM> includes information indicating that the frame was transmitted by the base station (AP) <NUM>. This information includes, for example, a MAC address indicating the base station <NUM>.

MBO Band Info <NUM> can include information indicating candidates for the frequency band and frequency bandwidth to be used for multiband transmission in the Data Transmission, which has been set by the base station <NUM>. For example, candidates for the frequency band and frequency bandwidth to be used for multiband transmission, selected from the information included in the MB Req-I (e.g., a frequency band and frequency bandwidth which the terminal device <NUM> can use for multiband transmission), may be included in the MBO Band Info <NUM>. Additionally, for example, information pertaining to the priority of each candidate may be included in the MBO Band Info <NUM>. Note that if multiband transmission is not possible, this MBO Band Info <NUM> may include information indicating that multiband transmission is not possible.

An example of the flow of the MB configuration processing by the terminal device <NUM> according to the present embodiment will be described with reference to the flowchart in <FIG>. In the present embodiment too, the control unit <NUM> of the terminal device <NUM> performs the MB configuration processing through basically the same flow as in the first embodiment (<FIG>).

When the MB configuration processing is started, in step S401, the control unit <NUM> of the terminal device <NUM> refers to the capability information of the base station (AP) <NUM> obtained in the Capability Exchange (step S101) phase, and determines whether or not the MB Configuration of the present embodiment is indicated as being possible by Flag-I <NUM> of MBO Capabilities <NUM> in the capability frame <NUM>.

If the information indicating that the base station <NUM> can execute the MB configuration is included in the Flag-I <NUM>, and it is determined that the base station <NUM> is capable of executing the MB Configuration, the processing moves to step S402.

In step S402, the control unit <NUM> determines whether or not there is a frequency band in which the backoff has ended. If it is determined that there is no such frequency band, the processing moves to step S403.

In step S403, the control unit <NUM> stands by until the backoff ends. The processing moves to step S404 when the processing of step S403 ends. If it is determined in step S402 that there is a frequency band in which the backoff has ended, the processing of step S403 is skipped, and the processing moves to step S404.

In step S404, the control unit <NUM> determines whether or not a plurality of frequency bands among the frequency bands in which the terminal device <NUM> is capable of multiband transmission are idle. In other words, when the backoff ends in one of the frequency bands, the control unit <NUM> determines whether there is another frequency band that is in the Idle state.

In the present embodiment too, any method can be used to determine whether or not the state is the Idle state in step S404. For example, the state may be determined to be the Idle state when none of the following three conditions ((<NUM>) to (<NUM>)) are met.

If it is determined in step S404 that a plurality of frequency bands are in the Idle state, i.e., when the backoff ends for one of the frequency bands, there is another frequency band in the Idle state, the processing moves to step S405.

In step S405, the control unit <NUM> controls the communication unit <NUM> or the communication unit <NUM> to acquire transmission rights in the frequency band in which the backoff has ended (Band <NUM>, in the case of the example in <FIG>), and to transmit the MB Request-I for multiband transmission to the base station <NUM> using that frequency band (Band <NUM>, in the case of the example in <FIG>). In other words, the control unit <NUM> causes the control signal for wireless communication in another frequency band to be transmitted in the frequency band which is capable of transmission.

The MB Announcement (MB Info) is transmitted from the base station <NUM> as a response signal to the MB Req-I transmitted in this manner. The communication unit <NUM>, the communication unit <NUM>, or both receive this MB Info. In step S406, the control unit <NUM> determines whether or not the communication unit <NUM>, the communication unit <NUM>, or both have received the MB Info in any of the frequency bands from the base station <NUM>.

The processing moves to step S407 if it is determined that the MB Info has not been received in any of the frequency bands. In step S407, the control unit <NUM> determines whether or not to make a retransmission request for the MB Info. The processing moves to step S408 when it is determined to make a retransmission request. In step S408, the control unit <NUM> controls the communication unit <NUM>, the communication unit <NUM>, or both to request the base station <NUM> to retransmit the MB Info. Once the processing of step S408 ends, the processing returns to step S406, and the processing following thereafter is repeated. This retransmission request is repeated a predetermined number of times or for a predetermined period if no MB Info is received.

Then, in step S406, if it is determined that the MB Info has been received in any of the frequency bands, the processing moves to step S409.

In step S409, the control unit <NUM> refers to the MB Info received by the communication unit <NUM>, the communication unit <NUM>, or both, and determines the frequency band/frequency bandwidth to be used for multiband transmission in the Data Transmission from among the candidates for the frequency band/frequency bandwidth indicated in the MBO Band Info <NUM> of that MB Info frame <NUM> (the candidates for the frequency band/frequency bandwidth to be used for multiband transmission, set by the base station <NUM>). In other words, in the present embodiment, the frequency band/frequency bandwidth to be used in multiband transmission is determined by the terminal device <NUM>.

As described above, by determining the frequency band/frequency bandwidth to be used for multiband transmission, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, multiband transmission is performed in the Data Transmission.

Note that when the received MB Info indicates that multiband transmission is not possible, the processing of step S410, described later, may be executed instead of the above-described processing of step S409.

Additionally, in step S401, if the information indicating that the base station <NUM> cannot execute the MB configuration is included in the Flag-I <NUM>, and it is determined that the base station <NUM> is not capable of executing the MB Configuration, the processing moves to step S410. Additionally, in step S404, if it is determined that the plurality of frequency bands are not in the Idle state and multiband transmission cannot be performed, the processing moves to step S410. Additionally, in step S407, if the MB Info retransmission request is repeated a predetermined number of times or for a predetermined period and it is determined that no further MB Info retransmission requests are to be made, the processing moves to step S410.

In other words, in these cases, the control unit <NUM> gives up on the multiband transmission, and transmits the data using a single frequency band in which data can be transmitted (single-band transmission). In other words, in step S410, the control unit <NUM> controls the communication unit <NUM> or the communication unit <NUM>, and determines the frequency band/frequency bandwidth for which the backoff has ended as the frequency band/frequency bandwidth to be used for data transmission (single-band transmission). In other words, in this case, the control unit <NUM> obtains the transmission rights independently for each frequency band.

Once the processing of step S410 ends, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, single-band transmission is performed in the Data Transmission.

As in the first embodiment, in the present embodiment as well, any of the wireless control units <NUM> may perform the MB configuration processing, a plurality of the wireless control units <NUM> may perform the MB configuration processing cooperatively, or the control unit <NUM> and the wireless control unit <NUM> may perform the MB configuration processing cooperatively.

As in the first embodiment, in the present embodiment, in the MB Configuration (step S103), the base station (AP) <NUM> executes the MB configuration processing in response to the MB configuration processing by the terminal device (STA) <NUM> described above. An example of the flow of the MB configuration processing by the base station <NUM> will be described with reference to the flowchart in <FIG>. In the present embodiment too, the control unit <NUM> of the base station <NUM> performs the MB configuration processing through basically the same flow as in the first embodiment (<FIG>).

When the MB configuration processing is started, in step S451, the control unit <NUM> of the base station <NUM> controls the communication unit <NUM> or the communication unit <NUM> and receives the MB Request-I, transmitted from the terminal device <NUM>, in any of the frequency bands in which reception is possible.

In step S452, the control unit <NUM> determines whether or not there is a frequency band in the Idle state aside from the frequency band in which the MB Request-I was received. Any method can be used to determine whether or not the state is the Idle state. For example, the state may be determined to be the Idle state when none of the three conditions ((<NUM>) to (<NUM>)) described above in <MB Configuration Processing by Terminal Device> are met. When it is determined that there is a frequency band in the Idle state, the processing moves to step S453.

In step S453, the control unit <NUM> sets the frequency band/frequency bandwidth that can be used for multiband transmission (i.e., candidates for the frequency band/frequency bandwidth to be used for multiband transmission), and stores information indicating the set candidates in the MBO Band Info <NUM> of the MB Info frame <NUM>. The processing moves to step S455 when the MB Info is generated in this manner.

Additionally, in step S452, if it is determined that there is no other frequency band in the Idle state, the processing moves to step S454.

In step S454, the control unit <NUM> stores information indicating that data can be transmitted in the frequency band in which the MB Request-I was received (or information indicating that multiband transmission is not possible) in the MBO Band Info <NUM> of the MB Info frame <NUM>. The processing moves to step S455 when the MB Info is generated in this manner.

In step S455, the control unit <NUM> controls the communication unit <NUM>, the communication unit <NUM>, or both to transmit the MB Info generated in step S453 or step S454 to the terminal device <NUM> as a response signal to the MB Request-I. As described above with reference to <FIG>, this MB Info can be transmitted in any frequency band.

Once the MB Info is transmitted in this manner, the MB configuration processing ends and transitions to the Data Transmission phase. In this case, multiband transmission or single-band transmission is performed in the Data Transmission. For example, if the MB Info has been generated through the processing of step S453, multiband transmission is performed in the Data Transmission. Alternatively, if the MB Info has been generated through the processing of step S454, single-band transmission is performed in the Data Transmission.

Like the first embodiment, in the present embodiment, by performing the MB configuration processing as described above, the terminal device <NUM> can shift a frequency band which is in an Idle state (a standby state) to a state in which transmission is possible immediately on the basis of the MB Info transmitted from the base station <NUM>. This makes it possible for the terminal device <NUM> to suppress an increase in the transmission standby time caused by multiband transmission.

Additionally, by shortening this transmission standby time, the terminal device <NUM> can suppress a drop in the opportunities to acquire the transmission rights for multiband transmission in a random access scheme. Furthermore, by transmitting the MB Request-I using the frequency band for which transmission rights have already been acquired, the terminal device <NUM> can suppress the occurrence of collisions caused by transmitting the MB Request-I. Accordingly, a drop in the efficiency of frequency band usage by wireless communication can be suppressed (or more typically, the efficiency of usage can be improved) for the entire wireless communication system <NUM>. Additionally, by transmitting the MB Info, the terminal device <NUM> can suppress the occurrence of collisions caused by other communication when receiving data, even if the back-off time is reduced.

Note that when the base station <NUM> transmits the same MB Info in a plurality of frequency bands, a diversity effect in those frequency bands can be obtained. This makes it possible to suppress a drop in the probability that the terminal device <NUM> will receive that MB Info (or more typically, improve that probability).

Note that any configurations can be used for the base station <NUM> and the terminal device <NUM>, and the configuration is not limited to the example in <FIG>. For example, there may be three or more communication units. In other words, multiband transmission may be performed using three or more frequency bands as candidates. Note also that the multiband transmission may be performed using three or more frequency bands.

Additionally, although the communication unit <NUM> and the communication unit <NUM> may be separate constituent elements as in the example in <FIG>, the configuration is not limited thereto, and some of the constituent elements among the communication unit <NUM> and the communication unit <NUM> may be shared. For example, a single wireless control unit <NUM> may be shared by the communication unit <NUM> and the communication unit <NUM>, as illustrated in <FIG>. In this case, the wireless control unit <NUM> can exchange information with each of the processing units in the communication unit <NUM> and the communication unit <NUM>. Likewise, a single data processing unit <NUM> may be shared by the communication unit <NUM> and the communication unit <NUM>. Likewise, a single modulation/demodulation unit <NUM> may be shared by the communication unit <NUM> and the communication unit <NUM>.

Additionally, the amplifier unit <NUM> may have its own functions incorporated into the wireless interface unit <NUM> corresponding to that amplifier unit <NUM>.

Although the foregoing describes the base station <NUM> and the terminal device <NUM> as handling a plurality of frequency bands (being capable of wireless communication in a plurality of frequency bands), and furthermore handling a plurality of channels in each frequency band, the configuration is not limited thereto, and the base station <NUM> and the terminal device <NUM> may be capable of handling a plurality of frequency bands and a single channel in each frequency band. In other words, the communication unit <NUM> and the communication unit <NUM> of the base station <NUM> and he terminal device <NUM> may each correspond to a single channel.

Additionally, the "frequency bands" used in the multiband transmission (synchronized transmission in a plurality of frequency bands) are not limited to the frequency bands (bands) described above in the first embodiment and the second embodiment, and may instead be channels to which the sets of the wireless interface unit <NUM> to the antenna <NUM> respectively correspond. In other words, the present technique can also be applied in synchronized transmission in a plurality of channels.

For example, the base station <NUM> and the terminal device <NUM> may handle a single frequency band and a plurality of channels in that frequency band. In other words, the base station <NUM> and the terminal device <NUM> may each include a single communication unit (the communication unit <NUM> or the communication unit <NUM>), and may perform multiband transmission using a plurality of channels through that single communication unit.

Note that the present technique can also be applied to purposes aside from multiband transmission control. For example, it is also possible to use a frequency band in which transmission is possible (e.g., Band <NUM>) to send and receive control signals for wireless communication in another frequency band (e.g., Band <NUM>), and on the basis of the control signals, start wireless communication in the other frequency band (e.g., Band <NUM>) and end wireless communication in the frequency band in which the control signals were sent and received (e.g., Band <NUM>). The present technique can also be applied in this kind of switching (updating) of the frequency band to be used.

The series of processing described above can be executed by hardware, and can be executed by software. In the case where the series of processing is executed by software, a program that configures the software is installed on a computer. Here, the computer includes, for example, a computer built in dedicated hardware and a general-purpose personal computer in which various programs are installed to be able to execute various functions.

<FIG> is a block diagram illustrating an example of hardware configuration of a computer that executes the series of processing described above according to a program.

In a computer <NUM> illustrated in <FIG>, a Central Processing Unit (CPU) <NUM>, Read Only Memory (ROM) <NUM>, and Random Access Memory (RAM) <NUM> are connected to each other by a bus <NUM>.

An input/output interface <NUM> is also connected to the bus <NUM>. An input unit <NUM>, an output unit <NUM>, a storage unit <NUM>, a communication unit <NUM>, and a drive <NUM> are connected to the input/output interface <NUM>.

The input unit <NUM> includes, for example, a keyboard, a mouse, a microphone, a touch panel, an input terminal, and the like. The output unit <NUM> includes, for example, a display, a speaker, an output terminal, and the like. The storage unit <NUM> includes, for example, a hard disk, a RAM disk, and non-volatile memory, and the like. The communication unit <NUM> includes, for example, a network interface. The drive <NUM> drives a removable medium <NUM> such as a magnetic disk, an optical disc, a magneto-optical disk, semiconductor memory, or the like.

In the computer configured as described above, for example, the CPU <NUM> loads a program stored in the storage unit <NUM> into the RAM <NUM> via the input/output interface <NUM> and the bus <NUM> and executes the program to perform the series of processing described above. Data and the like necessary for the CPU <NUM> to execute the various kinds of processing is also stored as appropriate in the RAM <NUM>.

The program executed by the computer can be recorded in, for example, the removable medium <NUM> as a package medium or the like and provided in such a form. In this case, the program may be installed in the storage unit <NUM> via the input/output interface <NUM> by inserting the removable medium <NUM> into the drive <NUM>.

Additionally, the program may also be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting. In this case, the program can be received by the communication unit <NUM> and installed in the storage unit <NUM>.

In addition, this program may be installed in advance in the ROM <NUM>, the storage unit <NUM>, or the like.

The present technique can be applied to any desired configuration. For example, the present technique can be applied as the configuration of part of a device, such as a processor serving as a system Large Scale Integration (LSI) circuit (e.g., a wireless communication processor), a module using a plurality of processors and the like (e.g., a wireless communication module), a unit using a plurality of modules and the like (e.g., a wireless communication unit), a set in which other functions are added to a unit (e.g., a wireless communication set), and the like.

For example, the present technique can also be applied in a network system constituted by a plurality of devices. For example, the present technique may be implemented as cloud computing shared and processed in common by a plurality of devices over a network. For example, the present technique may be implemented in a cloud service that provides services to any desired terminal, such as a computer, a mobile information processing terminal, an Internet of Things (IoT) device, or the like.

Note that, in the present specification, "system" means a set of a plurality of constituent elements (devices, modules (components), or the like), and it does not matter whether or not all the constituent elements are provided in a single housing. Therefore, a plurality of devices contained in separate housings and connected over a network, and one device in which a plurality of modules are contained in one housing, are both "systems".

A system, a device, a processing unit, or the like in which the present technique is applied can be used in any field, such as, for example, transportation, medical care, crime prevention, agriculture, livestock industry, mining, beauty, factories, home appliances, weather, nature monitoring, and the like. The application of the present technique can also be implemented as desired.

The embodiments of the present technique are not limited to the above-described embodiments, and various modifications can be made within the scope of the amended claims.

For example, configurations described as one device (or one processing unit) may be divided to be configured as a plurality of devices (or processing units). Conversely, configurations described as a plurality of devices (or processing units) in the foregoing may be collectively configured as one device (or one processing unit). Configurations other than those described above may of course be added to the configuration of each device (or each processing unit). Furthermore, part of the configuration of one device (or one processing unit) may be included in the configuration of another device (or another processing unit) as long as the configuration or operation of the entire system is substantially the same.

Additionally, for example, the program described above may be executed on any device. In this case, the device may have necessary functions (function blocks and the like) and may be capable of obtaining necessary information.

For example, each step of a single flowchart may be executed by a single device, or may be executed cooperatively by a plurality of devices. Furthermore, if a single step includes a plurality of processes, the plurality of processes may be executed by a single device or shared by a plurality of devices. In other words, the plurality of kinds of processing included in the single step may be executed as processing for a plurality of steps. Conversely, processing described as a plurality of steps may be collectively executed as a single step.

Additionally, for example, the program executed by the computer may be such that the processing steps describing the program are executed in chronological order according to the order described in the present specification or are executed in parallel or individually at a necessary timing such as in response to a call. That is, as long as no contradiction arises, the processing steps may be executed in an order different from the order described above. Furthermore, the processing steps describing the program may be executed in parallel with the processing of another program or may be executed in combination with the processing of the other program.

Claim 1:
A wireless communication device (<NUM>), comprising:
a wireless communication unit (<NUM>, <NUM>) configured to perform wireless communication in a plurality of frequency bands; and
a control unit (<NUM>) configured to control the wireless communication unit to transmit a control signal in a second frequency band, the control signal being for wireless communication in a first frequency band; characterized in that the control signal includes information indicating candidates for a frequency band in which the wireless communication is to be performed; and
the control signal further includes information pertaining to a priority of the candidates.