Communication control device and communication control method

Abstract

To provide a communication apparatus that achieves a high efficiency in carrier aggregation.SOLUTION: A communication apparatus includes a communication section that transmits and receives a radio signal using a first communication band and a second communication band, and a controller that controls an operation of communication performed by the communication section. The controller performs control such that a signal that includes information regarding a clear channel of the second communication band is transmitted using a channel of the first communication band. Further, the controller performs control such that data is transmitted to a transmission destination of the signal using one of a plurality of the clear channels of the second communication band, the plurality of the clear channels of the second communication band being included in the signal.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a communication device and a communication method for transmitting and receiving wireless signals. [Background technology]

[0002] In order to cope with the recent increase in data traffic demand, there is a demand for expanding data capacity and improving peak throughput in wireless LANs (Local Area Networks). One method to achieve this is carrier aggregation, which enables communication by simultaneously using multiple frequency bands, and is expected to be standardized in the next generation of IEEE802.11.

[0003] With current channel access using CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance), carrier sensing is performed on the primary channel (PCH) of each frequency band, and communication using carrier aggregation cannot begin unless communication is in progress on the PCHs of all bands (hereinafter referred to as the "idle state"). In other words, even if the PCHs of one band are idle, if the PCHs of other bands are not idle, the transmitting terminal must wait until all PCHs transition to the idle state, and the overhead of waiting for transmission reduces communication efficiency.

[0004] In addition, a wireless communication device has been proposed that uses statistical data to communicate by timing when each channel is idle (see, for example, Patent Document 1), but there is a concern that this will significantly increase the processing load of the transmitting terminal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-28746 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the technology disclosed in this specification is to provide a communication device and a communication method that perform channel access using CSMA / CA. [Means for solving the problem]

[0007] The technology disclosed in this specification has been made in consideration of the above problems, and a first aspect thereof is: a communication unit that transmits and receives wireless signals using a first communication band and a second communication band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls to transmit a signal including information about an available channel in the second communication band using a channel on the first communication band. It is a communication device.

[0008] The control unit also controls data transmission to the destination of the signal using any one of a plurality of available channels included in the signal in the second communication band.

[0009] Alternatively, the control unit controls data transmission to be performed using a channel indicated in a response signal from the destination of the signal, out of a plurality of available channels included in the signal.

[0010] A second aspect of the technology disclosed in this specification is: A communication method for performing wireless communication using a first communication band and a second communication band, transmitting a signal including information about available channels in the second communication band using a channel on the first communication band; transmitting data to a destination of the signal using the free channel included in the signal; It is a communication method having the following.

[0011] A third aspect of the technology disclosed in this specification is: a communication unit that transmits and receives wireless signals using a first communication band and a second communication band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls the receiving unit to receive a signal including information about an available channel in the second communication band on a channel in the first communication band. It is a communication device.

[0012] The control unit controls the receiving operation to be performed on any one of a plurality of free channels included in the signal addressed to itself.

[0013] Alternatively, the control unit may return a response signal including information on a channel selected from a plurality of available channels included in the signal addressed to itself, and control the receiving operation to be performed on the channel included in the response signal.

[0014] Furthermore, a fourth aspect of the technology disclosed in this specification is: A communication method for performing wireless communication using a first communication band and a second communication band, receiving a signal containing information about available channels in the second communications band on a channel in the first communications band; controlling data transmission and reception in the second communication band based on information included in the signal; It is a communication method having the following. [Effects of the Invention]

[0015] According to the technology disclosed in this specification, it is possible to provide a communication device and a communication method that realizes high efficiency of carrier aggregation while conforming to the channel access method according to CSMA / CA.

[0016] It should be noted that the effects described in this specification are merely examples, and the effects of the present invention are not limited to these. Furthermore, the present invention may also have additional effects in addition to the effects described above.

[0017] Further objects, features, and advantages of the technology disclosed in this specification will become apparent from the following detailed description based on the embodiments and accompanying drawings. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a communication system. [Figure 2] FIG. 2 is a diagram showing an example of the functional configuration of the communication device 200. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of operation for each communication band when data transmission is performed by carrier aggregation in two communication bands, Band A and Band B. In FIG. [Figure 4] FIG. 4 is a diagram showing an example of a communication sequence (first embodiment) realized by applying the technology proposed in this specification. [Figure 5] FIG. 5 is a diagram showing an example of the format of a CA pre-request frame and a CA pre-response frame. [Figure 6] FIG. 6 is a flowchart showing the detailed procedure of the CA transmission determination process. [Figure 7] FIG. 7 is a flowchart showing the detailed processing steps of the CA reception preparation processing and NAV setting. [Figure 8] FIG. 8 is a flowchart showing the detailed processing steps of the CA transmission preparation processing and NAV setting. [Figure 9] FIG. 9 is a diagram showing an example of operation for each communication band (first embodiment) when data transmission is performed by carrier aggregation in two communication bands, Band A and Band B. In FIG. [Figure 10] FIG. 10 is a diagram showing an example of a communication sequence (second embodiment) realized by applying the technology proposed in this specification. [Figure 11] FIG. 11 is a diagram showing an example of the format of a CA advance notification frame. [Figure 12] FIG. 12 is a flowchart showing the detailed procedure of the CA transmission preparation process. [Figure 13] FIG. 13 is a flowchart showing the detailed processing procedure of the CA reception preparation processing and NAV setting. [Figure 14] FIG. 14 is a diagram showing an example of the functional configuration of a communication device 1400. [Figure 15] FIG. 15 is a diagram showing an example of transmission using communication band Band A. [Figure 16] FIG. 16 is a diagram showing an example in which transmission is performed using two communication bands, Band A and Band B. [Figure 17] FIG. 17 is a diagram showing an arrangement of frequency channels available in a wireless LAN system. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the technology disclosed in this specification will be described in detail with reference to the drawings.

[0020] Figure 17 shows the allocation of frequency channels available for wireless LAN systems. This shows the channel allocation in the currently available 5 GHz band.

[0021] As shown in the top row of Figure 17, a configuration is shown in which channels are used in 20 MHz increments, with channels 36, 40, 44, 48, 52, 56, 60, and 64 arranged in ascending order of frequency. At even higher frequencies, channels 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144 are arranged.

[0022] 17 shows a configuration in which channels are used in 40 MHz increments, with channels 38, 46, 54, and 62 arranged in ascending order of frequency. At even higher frequencies, channels 102, 110, 118, 126, 134, and 142 are arranged.

[0023] 17 shows a configuration in which channels are used in 80 MHz increments, with channels 42 and 58 arranged in ascending order of frequency. At even higher frequencies, channels 106, 122, and 138 are arranged.

[0024] 17 shows a configuration in which channels are used in 160 MHz increments, with channel 50 arranged in ascending order of frequency. At even higher frequencies, channels up to 114 are arranged.

[0025] Note that the ranges of these available frequency channels shown in Figure 17 may differ depending on the legally available frequency bands in each country. Also, the method can be applied to other frequency bands (2.4 GHz band) and newly available (or unlicensed) frequency bands (6 GHz band), and can also be applied when these different frequency bands are used together.

[0026] In the following explanation, we will assume a communication system that simultaneously uses two frequency bands (hereinafter also referred to as "communication bands"), for example, 2.4 GHz and 5 GHz (or 6 GHz). When comparing the 2.4 GHz band with the 5 GHz band or 6 GHz band, it can be said that the 5 GHz band or 6 GHz communication band, which has a higher frequency, is more suitable for transmitting large amounts of data.

[0027] As shown in Figure 17, each communication band consists of multiple channels. Typically, in a network such as a Basic Service Set (BSS), a primary channel (PCH) that is primarily used during wireless communication is determined for each communication band. When a communication terminal performs channel access using CSMA / CA in a certain communication band, it performs carrier sensing on the PCH of that communication band.

[0028] Assuming that channels are used in 20 MHz increments, but with the expansion of bandwidth, channels will be used in increments of up to 160 MHz, a communication terminal will be able to perform carrier sensing over a 160 MHz width including the PCH, even when using channels in 20 MHz increments. Furthermore, when channels are used in 20 MHz increments, channels included in the 160 MHz carrier sense range including the PCH and for which carrier sensing is performed simultaneously (i.e., channels other than the PCH for which carrier sensing is performed) will be referred to as secondary channels (SCHs) hereinafter. When carrier sensing is performed on the PCH of a certain communication band, carrier sensing results for the SCH are also obtained at the same time. Similarly, when channels are used in 40 MHz or 80 MHz increments, channels other than the PCH for which carrier sensing is performed are referred to as SCHs.

[0029] 1 is a schematic diagram illustrating an example of the configuration of a communication system to which the technology disclosed in this specification is applied. The illustrated communication system is assumed to have a plurality of STAs (STAtions: child devices).

[0030] When STA1 and STA2 communicate data, it is assumed that they can simultaneously use the communication bands of Band A and Band B, i.e., they can communicate using carrier aggregation. Band A and Band B each include a primary channel (PCH).

[0031] Here, Band A and Band B refer to the 920 MHz band, 2.4 GHz band, and 5 GHz band currently allocated as unlicensed bands, as well as the 6 GHz band expected to be allocated as an unlicensed band in the future, and the combination of each band is not particularly limited. In addition, carrier aggregation using more than two communication bands may be performed between STA1 and STA2.

[0032] On the other hand, STA3 is another STA located within the range of the signals of STA1 and STA2. STA3 may belong to the same BSS as STA1 and STA2, or to a different BSS.

[0033] The configuration of a communication system to which the technology disclosed in this specification is applied is not limited to that shown in Fig. 1. It is sufficient that there are multiple communication devices with established connections, and that each communication device has a communication device as a peripheral terminal, and as long as this condition is met, the positional relationship does not matter. Furthermore, although not specifically mentioned in this specification, either STA1 or STA2 may be an AP (Access Point: base station).

[0034] 2 shows an example of the functional configuration of a communication device 200 that operates as an STA (including an AP). Each unit in the communication device 200 will be described below.

[0035] The communication control unit 201 controls the overall operation of the communication device 200, and also performs processing to pass control information to be notified to other communication terminals to the data processing unit 202. In this embodiment, the communication control unit 201 is characterized by selecting and switching transmission and reception channels in the wireless communication units 206 and 207 for communication by carrier aggregation, and generating and acquiring signals including carrier aggregation channel information.

[0036] The data processing unit 202 generates a transmission signal mainly based on transmission data from an upper layer and control information received from the communication control unit 201. The data processing unit 202 further demodulates the received signals received from the wireless communication units 206 and 207 and extracts the received data and control information.

[0037] The communication device 200 according to this embodiment is a communication terminal that performs communication by carrier aggregation using two communication bands, Band A and Band B. Therefore, as shown in Fig. 2, the data processing unit 202 shares the data processing unit 203 in the MAC (Media Access Control) layer, but is separated from the PHY layer into a data processing unit 204 for Band A and a data processing unit 205 for Band B. This is to enable simultaneous communication over a plurality of communication bands while commonly managing overall data (e.g., sequence numbers, etc.).

[0038] The wireless communication units 206 and 207 perform analog conversion and RF (Radio Frequency) processing on the transmission signals generated by the data processing unit 202 to generate wireless signals that are output from the antennas 208 and 209, respectively. The wireless communication units 206 and 207 also perform RF processing and digital conversion on the wireless signals input to the antennas 208 and 209 to generate received signals, which are then passed to the data processing unit 202. One of the wireless communication units, 206, processes wireless signals using Band A, and the other wireless communication unit, 207, processes wireless signals using Band B.

[0039] When MIMO (Multiple Input Multiple Output) communication is performed in Band A and Band B, each of the wireless communication units 206 and 207 is equipped with multiple antennas, and each of the PHY layer data processing units 204 and 205 performs spatial multiplexing and spatial separation processing.

[0040] Figure 3 shows an example of operation for each communication band when a transmitting terminal transmits data by carrier aggregation in two communication bands, Band A and Band B. Here, it is assumed that only the primary channel (PCH) is used for communication in each communication band.

[0041] For example, suppose a transmitting terminal performs backoff on the PCH of Band A and acquires the transmission right at time T301. At this time, if the transmitting terminal attempts carrier aggregation transmission using a channel of Band B, the transmitting terminal cannot start carrier aggregation transmission at this time if the PCH of Band B is in a state where other communication is being performed (hereinafter also referred to as a "busy state") as shown in Figure 3.

[0042] In such a situation, the transmitting terminal has no choice but to wait to transmit data until it acquires the transmission right in Band B again, or to give up on carrier aggregation and transmit data only in Band A.

[0043] In the former method, overhead increases due to unnecessary transmission standby time, the efficiency of carrier aggregation communication decreases, and the effect of improving throughput cannot be obtained. In the example shown in Fig. 3, the Busy state in the PCH of Band B is resolved at time T302, and data transmission (Data Tx) by carrier aggregation using the PCHs of Band A and Band B is not started until the transmission right is acquired at time T303 by restarting backoff. Therefore, the transmitting terminal must wait for transmission on the PCH of Band A from time T301 when the transmission right is acquired on the PCH of Band A until time T303 when backoff on the PCH of Band B ends.

[0044] On the other hand, the latter method reduces opportunities for carrier aggregation transmission, and in particular in a congested environment with many terminals, there is a risk that carrier aggregation transmission will not be possible at all.

[0045] Therefore, this specification proposes a technology for minimizing overhead due to transmission standby and increasing carrier aggregation transmission opportunities in order to improve throughput in a wireless LAN. According to the technology proposed in this specification, when a communication terminal acquires a transmission right in a certain communication band, it can dynamically select an idle channel in another communication band to perform carrier aggregation communication. When the communication terminal acquires a transmission right in the primary channel of one communication band, it selects an idle secondary channel if found in the other communication band even if the primary channel is busy, and performs carrier aggregation using both communication bands. [Example]

[0046] Figure 4 shows an example of a communication sequence realized by applying the technology proposed in this specification. STA1 is a terminal (Tx) that transmits data, STA2 is a terminal (Rx) that receives data, and STA3 is another terminal (Other) that is not involved in data transmission. The figure also shows a flow in which, when STA1 acquires the right to transmit on the PCH in Band A, it performs communication by carrier aggregation using an idle channel in Band B. The figure also shows a flow in which a surrounding communication terminal STA3 that does not communicate with either STA1 or STA2 sets a transmission standby state (Network Allocation Vector: NAV) in at least one of Band A or Band B.

[0047] First, STA1 and STA2 exchange capability information and information about the band in which they intend to transmit in an initiation process (SEQ401). The initiation process may be performed using the PCH of Band A, or may be performed using other channels or communication bands other than Band A.

[0048] The capability information includes information on which frequency bands can be used for communication and whether transmission and reception by carrier aggregation are possible. This initiation process does not have to be performed for each carrier aggregation communication. For example, it may be performed first to establish a link between STA1 and STA2, and then information may be exchanged when the communication situation between them changes. In the example communication sequence shown in Figure 4, it is assumed that a commitment to perform carrier aggregation is obtained between STA1 and STA2 through the initiation process.

[0049] When STA1 acquires a transmission right on the PCH of Band A (SEQ402), it performs a CA (Carrier Aggregation) transmission decision process (SEQ403). Specifically, STA1 determines whether the PCH of Band B is idle. If the PCH of Band B is not idle, STA1 transmits a CA pre-request frame using the PCH of Band A, which specifies one or more idle channels in Band B other than the idle PCH based on its own carrier sense result (SEQ404). For example, if STA1 simultaneously performs carrier sense on multiple channels (secondary channels (SCHs)) including the PCH, one or more idle channels are selected from the SCHs. Details of the CA transmission decision process will be described later (see FIG. 6). Details of the frame structure of the CA pre-request frame will be described later (see FIG. 5).

[0050] 4, if the PCH in Band B is also idle, STA1 will start transmitting data by carrier aggregation using the PCHs in Bands A and B. If an idle channel is not found in Band B (among the SCHs carrier-sensed simultaneously with the PCH), STA1 will either give up on carrier aggregation and transmit data only in Band A, or wait for transmission until it acquires the right to transmit in Band B as well and carrier aggregation becomes possible.

[0051] When STA2 receives a CA pre-request frame addressed to itself, it performs CA reception preparation processing (SEQ405). Specifically, STA2 compares the list of available channels included in the received frame with its own carrier sense results. STA2 then determines one of the available channels included in the list of available channels in the CA pre-request frame that has also been confirmed to be in an idle state by its own carrier sense results as the standby channel in Band B, and performs channel switching. Furthermore, when STA3 receives a CA pre-request frame not addressed to itself on the PCH in Band A, it performs NAV setting processing 1 on the PCH in Band A (SEQ406).

[0052] Details of the CA reception preparation and NAV setting process 1 will be described later (see FIG. 7). Details of the frame structure of the CA preliminary response frame will be described later (see FIG. 5).

[0053] STA2 then transmits a CA preliminary response frame containing information about its own standby channel to STA1 using the PCH in Band A (SEQ407). When STA1 receives the CA preliminary response frame addressed to itself from STA2, it performs CA transmission preparation processing (SEQ408). Specifically, STA1 switches the channel to an available channel (SCH) in Band B specified in the channel list information included in the received frame, preparing for data communication via carrier aggregation. On the other hand, when STA3 receives a CA preliminary response frame not addressed to itself, it performs NAV setting processing 2 for the channel in Band B listed in the received frame (SEQ409). Details of CA transmission preparation and NAV setting processing 2 will be described later (see FIG. 8).

[0054] STA1 then transmits data using carrier aggregation using Band A and Band B (SEQ410, 411). In response, STA2 returns an acknowledgement (Ack) in each of the communication bands, Band A and Band B (SEQ412, 413).

[0055] After the carrier aggregation communication between STA1 and STA2 is completed in this manner, both STA1 and STA2 reset the channel used in Band B (from the SCH used for the carrier aggregation communication) to the PCH (SEQ414, 415), and this process is terminated.

[0056] 4, the CA pre-response frame transmitted by STA2 is transmitted only on Band A (PCH), but it may also be transmitted on the channel (SCH) after switching to Band B. In this way, it is possible to have a terminal belonging to another BSS (Other BSS: OBSS) that always uses the channel after switching to Band B set its NAV, thereby preventing collisions in data communications due to carrier aggregation.

[0057] Figure 5 shows examples of the formats of a CA pre-request frame and a CA pre-response frame. The frame format shown in the figure is based on the format of the IEEE 802.11 action frame and is realized by defining an index in the Frame Control field that indicates a new frame type.

[0058] Frame Control, denoted by reference number 501, is a field containing information indicating the type of action frame.

[0059] Duration, indicated by reference number 502, is a field containing time information until the subsequent carrier aggregation communication ends. A surrounding terminal that is not performing communication reads the value of this field and sets NAV.

[0060] RA (Receiver Address) indicated by reference number 503 is a field containing the MAC address of the destination, and TA (Transmitter Address) indicated by reference number 504 is a field containing the MAC address of the source.

[0061] The Req. flag indicated by reference number 505 is a field that indicates flag information indicating whether the frame is a “CA pre-request frame” or a “CA pre-response frame.” For example, if this flag is “1,” it indicates that it is a CA pre-request frame, and if this flag is “0,” it indicates that it is a CA pre-response frame.

[0062] Num. Of Band indicated by reference number 506 is a field indicating the number of communication bands for which carrier aggregation is attempted.

[0063] The CH List In Band indicated by reference number 507 is a field containing channel information in a certain communication band (for which carrier aggregation is attempted). This frame contains as many CH List In Band fields as are indicated by the Num. Of Band field 506. In Fig. 5, it is assumed that the Num. Of Band field 506 indicates the number M of communication bands.

[0064] The CH List In Band field 507 includes a Band Info. field 511 indicating the communication band, a Num. Of CH field 512 indicating the number of channels in the communication band indicated in the Band Info. field 511, and a CH Info. field 513 indicating channel information for the number of channels indicated by Num. Of CH. A CA advance request frame includes as many CH Info. fields 513 as there are candidate channels for each communication band, but a CA advance response frame has only one CH Info. field in the CH List In Band field 507.

[0065] Specifically, a transmitting terminal that transmits data using carrier aggregation writes information indicating the communication band (Band A) used to transmit this CA pre-request frame and the communication band (Band B) to be aggregated in the Band Info. field 511 of the CA pre-request frame, writes the number of candidate channels (SCHs) that the transmitting terminal itself has confirmed to be idle within the communication band to be aggregated in the Num. Of CH field 512, and writes information indicating each candidate channel in each CH Info. field 513. In Figure 5, a communication band with N candidate channels is assumed. On the other hand, a receiving terminal that returns a CA pre-response frame writes information indicating one channel that it has selected for carrier aggregation from the candidate channels indicated in the CH List In Band field 507 of the CA pre-request frame.

[0066] Here, the values ​​indicated by the Band Info. field 511 and the CH Info. field 513 are not particularly limited as long as they are identifiers shared among the communication terminals STA1, STA2, and STA3. For example, the Operating Class as specified in IEEE802.11-2016 Annex.E may be used as the Band Info., and the channel number in the Channel Set may be used as the CH Info.

[0067] An FCS (Frame Check Sequence) indicated by reference number 508 is a field that indicates an error correction code for the entire frame.

[0068] FIG. 6 shows, in the form of a flowchart, detailed processing steps of the CA transmission determination processing performed by STA1 (or performed by the data transmitting terminal) in SEQ403 in the communication sequence shown in FIG.

[0069] After acquiring the right to transmit on the PCH of Band A (step S601), STA1 checks whether the PCH of Band B is in an idle state (step S602).

[0070] If the PCH of Band B is idle (Yes in step S602), STA1 starts communication using carrier aggregation using the PCHs of both Band A and Band B (step S607). At this time, STA1 may perform RTS / CTS (Request To Send / Clear To Send) communication for collision avoidance before starting data communication. Also, both Band A and Band B may be wideband to start data transmission.

[0071] On the other hand, if the PCH of Band B is busy (No in step S602), STA1 checks the carrier sense results of channels other than the PCH of Band B (step S603). The channels other than the PCH are, for example, SCHs on which STA1 performed carrier sense simultaneously with the PCH.

[0072] If STA1 finds at least one channel in Band B that is detected to be in an idle state (Yes in step S604), it generates a CA pre-request frame (see FIG. 5) in which Band Info. field 511 indicates Band B, Num. Of Band field 512 indicates the number of channels detected to be in an idle state, and CH Info. field 513 carries CH List In Band field 507 indicating information about the channels detected to be in an idle state, and transmits this frame to STA2 using the PCH of Band A (step S605). The communication sequence shown in FIG. 4 assumes the case where the result in step S604 is Yes.

[0073] Furthermore, if STA1 cannot detect any idle channels in Band B (No in step S604), it either gives up on carrier aggregation and starts normal communication using only the PCH in Band A, or waits to transmit data using carrier aggregation until it acquires the right to transmit in Band B (step S606).

[0074] The carrier sensing method used by STA1 and other devices is not critical. For example, in accordance with the secondary channel carrier sensing method specified in IEEE802.11, specifically, a channel that does not detect a certain level of power during PIFS (Point Coordination Function (PCF) Inter Frame Space) (25 microseconds) may be detected as idle. Also, if the transmitting terminal has wireless devices for multiple communication bands, each wireless device may be configured with a separate channel, and a channel that does not detect a preamble during the backoff period may be detected as idle.

[0075] Also, if there are three or more bands for carrier aggregation, in step S603, STA1 checks the carrier sense results for each band, and in step S605, it transmits a CA pre-request frame containing information on multiple candidate channels for each communication band (i.e., containing multiple CH List In Band fields).

[0076] Figure 7 shows in flowchart form the detailed processing steps of the CA reception preparation process and NAV setting, which are performed by STA2 and STA3, respectively, at SEQ405 and SEQ406 in the communication sequence shown in Figure 4 (or performed by the data receiving terminal or other terminal not involved in data transmission).

[0077] When a STA receives a CA pre-request frame transmitted in Band A from another terminal (e.g., STA1) that is attempting to transmit data using carrier aggregation (step S701), it determines from the RA field whether the frame is addressed to the STA (step S702).

[0078] If the received CA pre-request frame is addressed to the STA (Yes in step S702), the STA proceeds to CA reception processing (if the STA is STA2 in the example communication sequence shown in FIG. 4). If the received CA pre-request frame is not addressed to the STA (No in step S702), the STA proceeds to NAV setting processing 1 (if the STA is STA3 in the example communication sequence shown in FIG. 4). The following explains each step in turn.

[0079] First, we will explain the CA reception process by STA 2. After STA 2 receives a CA pre-request frame addressed to itself from STA 1 (Yes in step S702), STA 2 checks its own carrier sense results for each candidate channel stored in the CH List In Band field 507 indicating Band B (step S703).

[0080] Here, if there is one or more candidate channels in the CH List In Band field 507 that STA2 has detected as being in an idle state (Yes in step S704), STA2 selects a channel to use for carrier aggregation communication from among them and switches the channel in Band B from PCH to the selected channel (step S705).

[0081] STA2 then transmits a CA preliminary response frame, in which information about Band B is included in Band Info field 511 and information about the selected channel is included in CH Info. field 513, to the sender of the CA preliminary request frame (step S706). Note that the CA preliminary response frame specifies only one channel to be used for carrier aggregation within Band B for the CA preliminary request frame, so only one CH Info. is stored in CH List In Band field 507.

[0082] Thereafter, STA2 waits for reception on the PCH of Band A and the selected channel of Band B (step S707). The communication sequence shown in Fig. 4 assumes the case where the result of step S704 is Yes.

[0083] On the other hand, if STA2 has detected that none of the channels in the list are in the idle state (No in step S704), STA2 transmits a CA pre-response frame to STA1 that does not include the CH List In Band field 507 indicating Band B (step S708). In this case, STA1 receives the CA pre-response frame and can determine that Band B cannot be used for carrier aggregation. Thereafter, STA2 waits for reception only on the PCH of Band A (step S709).

[0084] In step S705, STA2 may select a channel to use from multiple candidate channels using any method without any particular limitation. For example, STA2 may measure interference / noise levels while performing carrier sensing and select the channel with the lowest interference / noise. If there are three or more bands for carrier aggregation, STA2 checks the carrier sense results of each channel in the list stored in the CA pre-request frame from STA1 for each band, selects one channel for each band, and transmits a CA pre-response frame containing multiple CH List In Band fields to STA1.

[0085] Next, we will explain NAV setting process 1. After STA3 receives a CA pre-request frame not addressed to itself from STA1 (No in step S702), it reads the Duration information in that frame and sets the NAV in the PCH of Band A (step S710). This makes it possible to suppress transmission so as to prevent collisions in data communication between STA1 and STA2 that will be performed using the PCH of Band A later.

[0086] Figure 8 shows in flowchart form the detailed processing steps of the CA transmission preparation process and NAV setting, which are performed by STA1 and STA3, respectively, at SEQ408 and SEQ409 in the communication sequence shown in Figure 4 (or performed by the data sending terminal and other terminals not involved in data transmission).

[0087] When the STA receives a CA preliminary response frame transmitted from STA2 in Band A (step S801), the STA determines from the RA field whether the frame is addressed to itself (step S802).

[0088] If the received CA preliminary response frame is addressed to itself (Yes in step S802), the process proceeds to CA transmission processing (when the STA is STA1 in the example of the communication sequence shown in FIG. 4). If the received CA preliminary response frame is not addressed to itself (No in step S802), the process proceeds to NAV setting processing 2 (when the STA is STA3 in the example of the communication sequence shown in FIG. 4). The following explains the process in order.

[0089] First, a description will be given of the CA transmission preparation process by STA 1. When STA 1 receives a CA preliminary response frame addressed to itself from STA 2 (Yes in step S802), STA 1 checks the CH List In Band field 507 in this frame (step S803).

[0090] Here, if the received CA preliminary response frame contains a CH List In Band field 507 indicating Band B (Yes in step S803), STA1 switches Band B to the channel indicated by the CH Info. field 513 in the CH List In Band field 507 (step S804). Then, STA1 performs carrier aggregation in Band A and Band B on the channel after switching between the PCH of Band A and Band B, and starts data communication (step S805). The communication sequence shown in FIG. 4 assumes the case where Yes is determined in step S803.

[0091] On the other hand, if the CH List In Band field 507 indicating Band B is not included (No in step S803), STA1 gives up on data communication using carrier aggregation and starts data transmission only on the PCH of Band A (step S806).

[0092] Here, if STA1 is able to obtain information about channels detected as being in an idle state around the designated channel of Band B, in step S806 it may transmit data on a channel that is amplified by integrating the surrounding channels.

[0093] Furthermore, if there are three or more communication bands for which carrier aggregation is performed, STA1 starts data communication using carrier aggregation only in the communication bands included in the corresponding CH List in Band field 507.

[0094] Next, we will explain NAV setting process 2. When STA3 receives a CA preliminary response frame not addressed to itself from STA2 (No in step S802), it first sets the NAV in the PCH of Band A based on the Duration information of the received frame, as in NAV setting process 1 (step S807).

[0095] STA3 then determines whether the received CA preliminary response frame contains a CH List In Band field 507 indicating Band B (step S808). If the CH List In Band field 507 indicating Band B is present (Yes in step S808), STA3 further determines whether STA2, the source of the frame in Band B, belongs to the same BSS (step S809).

[0096] If the BSS is the same as STA2 (Yes in step S809), STA3 also sets NAV in the PCH of Band B (step S810). This is to prevent STA3 from starting unnecessary data transmission, because even if the PCH of Band B transitions from a busy state to an idle state, data communication between STA1 and STA2 has already been performed by switching channels within Band B.

[0097] Also, if there is no CH List In Band field 507 indicating Band B (No in step S808), STA3 does not need to set NAV in Band B, and therefore ends this process.

[0098] 9 shows an example of operation for each communication band in the present embodiment when a transmitting terminal transmits data by carrier aggregation in two communication bands, Band A and Band B. Here, it is assumed that in a communication band in which the primary channel (PCH) is busy, carrier aggregation is performed by switching to an idle secondary channel (SCH) (or an idle channel other than the PCH).

[0099] For example, suppose a transmitting terminal performs backoff on the PCH of Band A and acquires the transmission right at time T901. If the PCH of Band B is busy at this time, in the example shown in Fig. 3, the transmitting terminal has no choice but to wait for transmission until the PCH of Band B becomes idle or to abandon carrier aggregation communication. In contrast, in this embodiment, when the transmitting terminal detects an available channel other than the PCH in Band B (in the example shown in Fig. 9, SCH#1, one of the secondary channels of Band B) based on its own carrier sense result of Band B, it transmits a CA pre-request frame including information on SCH#1 in the CH Info. field 513 of Band B to the receiving terminal using the PCH of Band A at time T901.

[0100] When the receiving terminal confirms that SCH#1 of Band B is also idle at its own station, it temporarily switches the channel used in Band B from PCH to SCH#1, and at time T902, it uses PCH of Band A to return a CA advance response frame containing information about SCH#1 in CH Info. field 513. The receiving terminal then waits to receive data in Band A and Band B.

[0101] When the transmitting terminal confirms from the received CA advance response frame that SCH #1 of Band B is also in an idle state on the receiving terminal side, it switches the channel used in Band B from PCH to SCH #1 at time T903. Then, at time T904, the transmitting terminal performs carrier aggregation across the two communication bands, Band A and Band B, and performs data transmission (Data Tx). In other words, even if the PCH of Band B is busy, the transmitting terminal can perform carrier aggregation by switching channels to idle SCH #1 in Band B.

[0102] The receiving terminal is able to receive the data transmitted via carrier aggregation because it is waiting to receive data on the PCH of Band A and SCH#1 of Band B. If the receiving terminal successfully receives the data, it transmits an acknowledgement frame (Ack) on each of the communication bands of Band A and Band B at time T905.

[0103] Furthermore, at time T905, the transmitting terminal receives acknowledgement frames (Ack) from the receiving terminals in the communication bands of Band A and Band B, and then at time T906, resets the channel used in Band B from SCH#1 to PCH. Therefore, for the transmitting terminal, the period from time T903 to T906 is a "channel switching period" during which the channel used in Band B switches from PCH to SCH#1.

[0104] In this way, according to the operation example shown in Figure 9, by exchanging CA advance request frames and CA advance response frames between the transmitting terminal and the receiving terminal, it is possible to negotiate the channel to be temporarily used during carrier aggregation communication, thereby making it possible to carry out communication using carrier aggregation efficiently.

[0105] As in this embodiment, each transmitting and receiving terminal uses the carrier sense result to detect an available channel, thereby enabling reliable selection of a channel available for communication. Also, by having surrounding terminals set their NAVs based on the CA advance notification frame or CA advance response frame, packet collisions in carrier aggregation communication can be prevented.

[0106] According to the first embodiment, by exchanging CA advance request frames and CA advance response frames between the transmitting terminal and the receiving terminal, a channel to be temporarily used during carrier aggregation communication can be negotiated, thereby enabling efficient communication using carrier aggregation. Furthermore, by detecting an available channel using the carrier sense results of both the transmitting terminal and the receiving terminal, a channel available for communication can be reliably selected. Furthermore, by having surrounding terminals set their NAVs based on the CA advance request frame or the CA advance response frame, packet collisions during carrier aggregation communication can be prevented. [Example]

[0107] In the first embodiment, an example has been described in which a transmitting terminal and a receiving terminal mutually determine a channel to be used for carrier aggregation using carrier sense results. In contrast, in the second embodiment, an example will be described in which a transmitting terminal uniquely selects a channel, and a receiving terminal uses the designated channel. Compared to the first embodiment, the second embodiment has the risk of not being able to reliably select a valid channel, but it can reduce the amount of processing on the receiving terminal side. Therefore, the second embodiment is effective, for example, in a case in which STA1, the transmitting terminal, is an AP and STA2, the receiving terminal, is a Non-AP STA.

[0108] 10 shows an example of a communication sequence realized by applying the technology proposed in this specification (second embodiment). STA1 is a data transmitting terminal (Tx), STA2 is a data receiving terminal (Rx), and STA3 is another terminal (Other) not involved in data transmission. The figure also shows a flow in which, when STA1 acquires the right to transmit on the PCH in Band A, it uniquely specifies an available channel in Band B (or a channel used for carrier aggregation) and performs communication by carrier aggregation. The figure also shows a flow in which a nearby communication terminal STA3, which does not communicate with either STA1 or STA2, sets its NAV in at least one of Band A or Band B.

[0109] First, STA1 and STA2 exchange capability information and information about the band in which they intend to transmit in an initiation process (SEQ1001). The initiation process may be performed using the PCH of Band A, or may be performed using other channels or communication bands other than Band A.

[0110] The capability information includes information on which frequency bands can be used for communication and whether transmission and reception by carrier aggregation are possible. This initiation process does not have to be performed for each carrier aggregation communication. For example, it may be performed first to establish a link between STA1 and STA2, and then information may be exchanged when the communication situation between them changes. In the communication sequence example shown in Figure 10, it is assumed that a commitment to perform carrier aggregation is obtained between STA1 and STA2 through the initiation process.

[0111] When STA1 acquires the transmission right on the PCH of Band A (SEQ1002), it prepares for CA transmission (SEQ1003). STA1 determines the SCH to use in Band B in preparation for CA transmission. Specifically, STA1 determines whether the PCH of Band B is idle. If the PCH of Band B is not idle, STA1 selects a channel (SCH) to use for carrier aggregation from one or more available channels other than the idle PCH in Band B based on its own carrier sense result, and switches to that channel to prepare for data communication using carrier aggregation. Next, STA1 transmits a CA advance notification frame describing the channel to use for carrier aggregation in Band B using the PCH of Band A (SEQ1004). Details of the CA transmission preparation process will be described later (see FIG. 12). Details of the frame structure of the CA advance notification frame will be described later (see FIG. 11).

[0112] 10, if the PCH in Band B is also idle, STA1 will start transmitting data by carrier aggregation using the PCHs in Bands A and B. If an idle channel is not found in Band B (among the SCHs carrier-sensed simultaneously with the PCH), STA1 will either give up on carrier aggregation and transmit data only in Band A, or wait for transmission until it acquires the right to transmit in Band B as well and carrier aggregation becomes possible.

[0113] When STA2 receives a CA advance notification frame addressed to itself, it performs a CA reception preparation process (SEQ1005). Specifically, STA2 determines the channel (SCH) of Band B specified in the received frame as the standby channel and performs channel switching. STA2 also transmits an Ack frame in response to the CA advance notification frame to STA1 using the PCH of Band A (SEQ1007). When STA3 receives a CA advance notification frame not addressed to itself on the PCH of Band A, it performs NAV setting process 1 on both the PCH of Band A and the channel in Band B specified in the CA advance notification frame (SEQ1006). Details of the CA reception preparation and NAV setting process will be described later (see FIG. 13).

[0114] When STA1 receives an acknowledgment (Ack) frame in response to the CA advance notification frame from STA2, it transmits data by carrier aggregation using the PCH in Band A and the vacant channel (SCH) in Band B (SEQ1008, 1009). In response, STA2 replies with an acknowledgment (Ack) in each of the communication bands of Band A and Band B (SEQ1010, 1011).

[0115] After the carrier aggregation communication between STA1 and STA2 is completed in this manner, both STA1 and STA2 reset the channel used in Band B to PCH (from SCH used for carrier aggregation communication) (SEQ1012, 1013), and this process ends.

[0116] 10, STA2 transmits an Ack frame using the PCH of Band A, but it may also transmit the Ack frame on the channel (SCH) after switching to Band B. In this way, it is possible to have a terminal belonging to another BSS (Other BSS: OBSS) that always uses the channel after switching to Band B set its NAV, thereby preventing collisions in data communications via carrier aggregation.

[0117] An example of the format of a CA advance notification frame is shown in Figure 11. The frame format shown in the figure is based on the format of the IEEE 802.11 action frame and is realized by defining an index in the Frame Control field that indicates a new frame type.

[0118] Frame Control, indicated by reference number 1101, is a field containing information indicating the type of action frame. Duration, indicated by reference number 1102, is a field containing time information until the subsequent carrier aggregation communication ends. Surrounding terminals that are not communicating read the value of this field and set NAV. RA, indicated by reference number 1103, is a field containing the MAC address of the destination, and TA, indicated by reference number 1104, is a field containing the MAC address of the source. Note that this frame is used only as a CA advance notification frame and is not shared with other frames, so a flag such as Req.flag (see Figure 5) is not necessary.

[0119] Num. Of Band, indicated by reference number 1105, is a field indicating the number of communication bands for which carrier aggregation is attempted. CH List In Band, indicated by reference number 1106, is a field containing channel information for a certain communication band. The frame contains as many CH List In Band fields as indicated by the Num. Of Band field.

[0120] The CH List In Band field 1106 includes a Band Info. field 1111 indicating the communication band, and a CH Info. field 1112 indicating channel information specifying the channel to be used for carrier aggregation within that communication band. In this embodiment, the transmitting terminal specifies one channel to be used for carrier aggregation for each communication band, so the CA advance notification frame has only one CH Info. field in the CH List In Band field 1106.

[0121] Specifically, a transmitting terminal that transmits data using carrier aggregation writes information in the Band Info. field 1111 of the CA advance notification frame indicating the communication band (Band A) to be used for transmitting this CA advance request frame and the communication band (Band B) to be aggregated, and writes information in the CH Info. field 1112 indicating one channel to be used for aggregation within the communication band (Band B) specified in the Band Info. field 1111.

[0122] Here, the values ​​indicated by the Band Info. field 1111 and the CH Info. field 1112 are not particularly limited as long as they are identifiers shared among the communication terminals STA1, STA2, and STA3. For example, the Operating Class as specified in IEEE802.11-2016 Annex.E may be used as the Band Info., and the channel number in the Channel Set may be used as the CH Info.

[0123] At the end of this frame, an FCS field 1107 indicating the error correction code for the entire frame is added.

[0124] FIG. 12 shows, in the form of a flowchart, detailed processing steps of the CA transmission preparation processing performed by STA1 (or performed by the data transmitting terminal) in SEQ1003 in the communication sequence shown in FIG.

[0125] After acquiring the right to transmit on the PCH of Band A (step S1201), STA1 checks whether the PCH of Band B is in an idle state (step S1202).

[0126] If the PCH of Band B is idle (Yes in step S1202), STA1 starts communication using carrier aggregation using the PCHs of both Band A and Band B (step S1207). At this time, STA1 may perform RTS / CTS communication for collision avoidance, for example, before starting data communication. Also, both Band A and Band B may be wideband to start data transmission.

[0127] On the other hand, if the PCH of Band B is busy (No in step S1202), STA1 checks the carrier sense results of channels other than the PCH of Band B (step S1203). The channels other than the PCH are, for example, SCHs on which STA1 performed carrier sense simultaneously with the PCH.

[0128] If STA1 finds at least one channel in Band B that is detected as being idle (Yes in step S1204), it selects one of those channels as the channel to use, generates a CA advance notification frame (see FIG. 11) with the Band Info. field indicating Band B and the CH Info. field carrying a CH List In Band field indicating selected channel information, and transmits this frame to STA2 using the PCH in Band A (step S1205). The communication sequence shown in FIG. 11 assumes the case where the result in step S1204 is Yes.

[0129] Furthermore, if STA1 cannot detect any idle channels in Band B (No in step S1204), it either gives up on carrier aggregation and starts normal communication using only the PCH in Band A, or waits to transmit data using carrier aggregation until it acquires the right to transmit in Band B (step S1206).

[0130] The carrier sensing method used by STA1 and other devices is not critical. For example, a channel that does not detect a certain level of power during a PIFS may be detected as idle, in accordance with the secondary channel carrier sensing method specified in IEEE 802.11. Furthermore, if the transmitting terminal has multiple Band B wireless devices, each wireless device may be configured with a different channel, and a channel that does not detect a preamble during the backoff period may be detected as idle.

[0131] Also, if there are three or more bands for carrier aggregation, in step S1203 STA1 checks the carrier sense results for each communication band, but ultimately selects one usable channel for each communication band, and in step S1205 transmits a CA advance request frame containing only one CH List In Band field.

[0132] Figure 13 shows in flowchart form the detailed processing steps of the CA reception preparation process and NAV setting, which are performed by STA2 and STA3, respectively, at SEQ1005 and SEQ1006 in the communication sequence shown in Figure 10 (or performed by the data receiving terminal or other terminal not involved in data transmission).

[0133] When a STA receives a CA advance notification frame transmitted in Band A from another terminal (e.g., STA1) that is attempting to transmit data using carrier aggregation (step S1301), it determines from the RA field whether the frame is addressed to the STA (step S1302).

[0134] If the received CA advance notification frame is addressed to itself (Yes in step S1302), the device proceeds to CA reception processing (STA2 in the example communication sequence shown in FIG. 10). If the received CA advance notification frame is not addressed to itself (No in step S1302), the device proceeds to NAV setting processing 1 (STA3 in the example communication sequence shown in FIG. 10). The following explains each step in order.

[0135] First, we will explain the CA reception process by STA 2. After STA 2 receives a CA advance notification frame addressed to itself from STA 1 (Yes in step S1302), it switches the channel to the channel (SCH) stored in the CH List In Band field indicating Band B (step S1303).

[0136] STA2 then returns an acknowledgment (Ack) frame to STA1 in response to the CA pre-notification frame using the PCH of Band A (step S1304). After that, STA2 waits for reception using the PCH of Band A and the SCH of Band B (step S1305).

[0137] Next, we will explain NAV setting process 1. After STA3 receives a CA advance notification frame not addressed to itself from STA1 (No in step S1302), it reads the Duration information in that frame and sets NAV in the PCH of Band A (step S1306). This makes it possible to suppress transmission so as to prevent collisions in data communication between STA1 and STA2 that will be performed later using the PCH of Band A.

[0138] Next, STA3 determines whether STA1, the source of the transmission, belongs to the same BSS (step S1307). If it does (Yes in step S1307), STA3 sets the NAV of the channel in Band B used for carrier aggregation (step S1308). This is to prevent STA3 from starting unnecessary data transmission, because even if the channel in Band B transitions from a busy state to an idle state, data communication between STA1 and STA2 has already been performed by switching channels in Band B.

[0139] According to the second embodiment, by transmitting a CA advance notification frame from a transmitting terminal to a receiving terminal, a channel to be temporarily used during carrier aggregation communication can be negotiated, thereby enabling efficient communication using carrier aggregation. Also, by having only the transmitting terminal search for an available channel using the carrier sense result, it is possible to reduce the processing load on the receiving terminal. Furthermore, by having surrounding terminals set their NAVs based on the CA advance notification frame, packet collisions during carrier aggregation communication can be prevented. [Example]

[0140] So far, we have explained the communication operation in carrier aggregation. In this embodiment, as an application of this, we will explain a channel switching technology that simultaneously uses a data communication channel and a control signal channel. Note that the communication sequence diagram and transmission frame used in this embodiment are the same as those in the first embodiment, so detailed explanations will be omitted here.

[0141] 14 shows an example of the functional configuration of a communication device 1400 that operates as an STA (including an AP). Each unit in the communication device 1400 will be described below.

[0142] The communication control unit 1401 controls the overall operation of the communication device 1400, and also performs processing to pass control information to be notified to other communication terminals to the data processing unit 1402. In this embodiment, the communication control unit 1401 is characterized by selecting and switching the transmission and reception channels in each of the wireless communication units 1405 and 1409 to perform communication by simultaneously using a data communication channel and a control signal channel, and generating and acquiring a signal including available channel information.

[0143] The communication device 1400 according to this embodiment uses two communication bands, Band A and Band B, but does not perform carrier aggregation as in the first and second embodiments described above. It is assumed that the two communication bands are assigned different uses and used individually. Specifically, Band B is assumed to be a relatively narrow band such as 2.4 GHz and is used for communication of control information with a small data size, while Band A is assumed to be a wide band such as 6 GHz and is used for communication of a large amount of data in response to requests from higher layers.

[0144] For this reason, the data processing unit that processes data in the MAC layer and PHY layer is separated into a data processing unit 1406 for Band A and a data processing unit 1402 for Band B. Data processing unit 1406 includes a data processing unit 1407 for the MAC layer for Band A and a data processing unit 1408 for the PHY layer for Band A. Data processing unit 1402 also includes a data processing unit 1403 for the MAC layer for Band B and a data processing unit 1404 for the PHY layer for Band B.

[0145] The data processing unit 1406 for Band A generates a transmission signal mainly based on transmission data from an upper layer. The data processing unit 1406 further demodulates a received signal received from the wireless communication unit 1409 for Band A and performs processing to extract the received data.

[0146] The data processing unit 1402 for Band B generates a transmission signal based on the control information received from the communication control unit 1401 for Band B. The data processing unit 1402 further demodulates the received signal received from the wireless communication unit 1405 for Band B and performs processing to extract the control information.

[0147] The wireless communication unit 1409 performs analog conversion and RF processing on the transmission signal generated by the data processing unit 1406, and generates a wireless signal using Band A from the antenna 1411. The wireless communication unit 1409 also performs RF processing and digital conversion on the wireless signal using Band A input to the antenna 1411, to generate a reception signal, and passes it to the data processing unit 1406.

[0148] The wireless communication unit 1405 performs analog conversion and RF processing on the transmission signal generated by the data processing unit 1402, and generates a wireless signal using Band B from the antenna 1410. The wireless communication unit 1405 also performs RF processing and digital conversion on the wireless signal using Band B input to the antenna 1410, to generate a reception signal, and passes it to the data processing unit 1402.

[0149] When MIMO communication is performed in Band A and Band B, each of the wireless communication units 1405 and 1409 is equipped with multiple antennas, and each of the PHY layer data processing units 1404 and 1408 performs spatial multiplexing and spatial separation processing.

[0150] The communication device 1400 shown in FIG. 14 can also be said to be a communication terminal equipped with wireless communication devices for multiple communication bands.

[0151] FIG. 15 shows an example in which a certain transmitting terminal transmits using communication band Band A.

[0152] For example, if a transmitting terminal is backing off on the PCH of Band A, it must wait for transmission when other channels in Band A (SCH1 and SCH2 in the example shown in Figure 5) become busy, even if they are idle. It is desirable for the transmitting terminal to switch to an idle channel for each data transmission. However, since the receiving terminal is only waiting on the PCH of Band A, data communication will not be performed correctly if the transmitting terminal switches channels.

[0153] 16 shows an example in which a transmitting terminal transmits data using two communication bands, Band A and Band B. However, in this figure, as explained in the first embodiment, it is assumed that data communication is performed by exchanging CA advance request frames and CA advance response frames between the transmitting terminal and the receiving terminal, and by flexible channel switching.

[0154] For example, when a transmitting terminal performs backoff on the PCH of the communication band Band B for control signals and acquires the transmission right at time T1601, it transmits a CA pre-request frame including its own carrier sense result in Band A for data communications to the receiving terminal using the PCH of Band B for control signals.

[0155] 16, at time T1601, the PCH of Band A is busy, but SCH#1 and SCH#2 are idle. Therefore, the transmitting terminal transmits a CA pre-request frame including information about SCH#1 and SCH#2 of Band A in the CH Info. field 513 of Band A.

[0156] When the receiving terminal confirms that SCH#1 and SCH#2 of Band A are also idle at its own station, it temporarily switches the channel in use in Band A from PCH to SCH#1 and SCH#2, and at time T1602, it uses PCH of Band B to return a CA advance response frame containing information about SCH#1 and SCH#2 of Band A in the CH Info. field 513 of Band A. The receiving terminal then waits to receive data on SCH#1 and SCH#2 of Band A.

[0157] When the transmitting terminal confirms from the received CA advance response frame that SCH#1 and SCH#2 of Band A are also idle on the receiving terminal side, it switches the channel used in Band B from PCH to SCH#1 (or SCH#2) at time T1603. Then, at time T1604, the transmitting terminal performs data transmission (Data Tx) using a wideband consisting of the two channels SCH#1 and SCH#2 in Band A. In other words, even if the PCH of the data transmission communication band Band A is busy, wideband transmission becomes possible by switching to the idle channel SCH#1 (or SCH#2) in Band A.

[0158] The receiving terminal is waiting to receive data on SCH#1 (or SCH#2) of Band A, and after receiving the preamble on SCH#1 (or SCH#2), it can receive the data transmitted over wideband on SCH#1 and SCH#2. If the receiving terminal has successfully received the data, it transmits an acknowledgement frame (Ack) using SCH#1 (or SCH#2) of the Band A channel at time T1605, and then resets the channel in use of Band A from SCH#1 (or SCH#2) to PCH.

[0159] Furthermore, when the transmitting terminal receives an acknowledgement frame (Ack) from the receiving terminal on SCH#1 (or SCH#2) of the Band A channel at time T1605, it then resets the channel used in Band A from SCH#1 (or SCH#2) to PCH at time T1606. Therefore, for the transmitting terminal, the period from time T1603 to T1606 is the "channel switching period" during which the channel used in Band A switches from PCH to SCH#1 (or SCH#2).

[0160] In this way, the receiving terminal can also switch its standby channel by exchanging CA advance notification frames and CA advance response frames between the transmitting terminal and the receiving terminal on the communication band Band B for control information, so data communication can be carried out correctly using any channel within the communication band Band A for data transmission.

[0161] Although the above describes an example using the frame exchange described in the first embodiment, even when the transmitting terminal uniquely determines the channel to use and transmits the CA advance notification frame as described in the second embodiment, the receiving terminal can switch the waiting channel on the communication band Band A for data transmission through the exchange of the CA advance notification frame and the CA advance response frame on the communication band Band B, thereby enabling correct data communication.

[0162] In addition, in this embodiment, Band A is positioned as being exclusively for data and Band B is positioned as being exclusively for control signals, but this is not particularly limited. Both Band A and Band B may be configured to transmit data and control signals. [Industrial Applicability]

[0163] Although the technology disclosed in this specification has been described in detail with reference to specific embodiments, it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the spirit of the technology disclosed in this specification.

[0164] The technology disclosed in this specification can be applied to, for example, an IEEE802.11 wireless LAN system, and can achieve high efficiency in carrier aggregation by switching to another idle channel according to the state of the primary channel of each communication band while following the channel access method based on CSMA / CA. Of course, the technology disclosed in this specification can also be suitably applied to wireless LAN systems other than the IEEE802.11 system.

[0165] In short, the technology disclosed in this specification has been described in the form of examples, and the contents of this specification should not be interpreted in a limiting manner. To determine the gist of the technology disclosed in this specification, the claims should be taken into consideration.

[0166] The technology disclosed in this specification can also be configured as follows.

[0167] (1) a communication unit that transmits and receives wireless signals using a first communication band and a second communication band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls to transmit a signal including information about an available channel in the second communication band using a channel on the first communication band. Communication equipment.

[0168] (2) the control unit controls data transmission to the destination of the signal using the free channel included in the signal; The communication device according to (1) above.

[0169] (3) the control unit controls data transmission to a destination of the signal using any one of a plurality of available channels included in the signal in the second communication band; A communication device according to either (1) or (2) above.

[0170] (4) The control unit controls the data transmission to be performed using a channel indicated in a response signal from the destination of the signal, among a plurality of available channels included in the signal. The communication device according to (3) above.

[0171] (5) The control unit controls the signal to include information about one available channel in the second communication band, and to transmit data to a destination of the signal using the one available channel in the second communication band. A communication device according to either (1) or (2) above.

[0172] (6) The control unit controls data transmission by carrier aggregation to a destination of the signal using each channel of the first communication band and the second communication band. A communication device according to any one of (1) to (5) above.

[0173] (7) The control unit controls data transmission to a destination of the signal using one or more of a plurality of available channels included in the signal in the second communication band. A communication device according to either (1) or (2) above.

[0174] (8) A communication method for performing wireless communication using a first communication band and a second communication band, transmitting a signal including information about available channels in the second communication band using a channel on the first communication band; transmitting data to a destination of the signal using the free channel included in the signal; A communication method comprising:

[0175] (9) a communication unit that transmits and receives wireless signals using the first communication band and the second communication band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls the receiving unit to receive a signal including information about an available channel in the second communication band on a channel in the first communication band. Communication equipment.

[0176] the control unit controls the receiving operation to be performed on the available channel in the second communication band in response to receiving the signal addressed to itself; The communication device according to (9) above.

[0177] (11) The control unit controls the receiving operation to be performed on any one of a plurality of available channels included in the signal addressed to itself. A communication device according to any one of (9) and (10) above.

[0178] (12) The control unit controls the control unit to return a response signal including information on a channel selected from a plurality of available channels included in the signal addressed to the control unit. A communication device according to any one of (9) and (10) above.

[0179] (13) The control unit controls the receiving operation to be performed on the channel included in the response signal. The communication device according to (12) above.

[0180] (14) The signal addressed to itself contains information about one free channel; the control unit controls the receiving operation to be performed on the one available channel. A communication device according to any one of (9) and (10) above.

[0181] (15) The control unit controls reception of data transmitted by carrier aggregation using each channel of the first communication band and the second communication band. A communication device according to any one of (9) to (14) above.

[0182] (16) The control unit controls the receiving operation to be performed on one or more of a plurality of free channels included in the signal addressed to itself in the second communication band. A communication device according to any one of (9) and (10) above.

[0183] (16-1) The control unit controls a receiving operation of data transmitted over a wide band using a plurality of channels of the second communication band. The communication device according to (16) above.

[0184] (17) In response to receiving the signal addressed to another station, the control unit controls the station to wait for transmission in the second communication band. The communication device according to (9) above.

[0185] (18) The control unit controls the communication device to wait for transmission in the second communication band in response to receiving a response signal to the signal from another station. The communication device according to (9) above.

[0186] (19) A communication method for performing wireless communication using a first communication band and a second communication band, receiving a signal containing information about available channels in the second communications band on a channel in the first communications band; controlling data transmission and reception in the second communication band based on information included in the signal; A communication method comprising: [Explanation of symbols]

[0187] 200... communication device, 201... communication control unit, 202... data processing unit 203...MAC layer data processing unit 204...PHY layer data processing unit (for Band A) 205...PHY layer data processing section (for Band B) 206...Wireless communication section (for Band A) 207...Wireless communication section (for Band B) 208...Antenna (for Band A) 209...Antenna (for Band B) 1400: communication device; 1401: communication control unit 1402...Data processing unit (for Band B) 1403...Data processing unit (MAC layer for Band B) 1404...Data processing unit (PHY layer for Band B) 1405...Wireless communication section (for Band B) 1406...Data processing unit (for Band B) 1407...Data processing unit (MAC layer for Band B) 1408...Data processing section (PHY layer for Band B) 1409...Wireless communication section (for Band B) 1410...Antenna (for Band B) 1411...Antenna (for Band A)

Claims

1. a control unit that controls a communication operation of a communication unit that transmits wireless signals by simultaneously using a first communication band and a second communication band different from the first communication band; the control unit controls the communication unit to transmit a first signal including information indicating a communication band for setting a transmission standby state (Network Allocation Vector: NAV) in a first device different from a device in which the communication unit is provided, using a channel on the first communication band; the information indicating the communication band includes information indicating the second communication band; Communications control device.

2. the control unit controls the communication unit to perform data transmission by simultaneously using a channel included in the first communication band and a channel included in the second communication band, based on a second signal transmitted in response to the first signal. The communication control device according to claim 1 .

3. the information indicating the communication band further includes information indicating a third communication band different from the second communication band; The communication control device according to claim 2 .

4. the second signal includes information indicating a predetermined channel included in the second communication band that causes the first device to set a transmission standby state (Network Allocation Vector: NAV); The communication control device according to claim 2 .

5. the control unit controls the communication unit to transmit data using a channel indicated by the second signal among a plurality of available channels included in the first signal. The communication control device according to claim 2 .

6. the control unit controls the communication unit to include information about one available channel in the second communication band in the first signal and to perform data transmission using the one available channel in the second communication band. The communication control device according to claim 1 .

7. the control unit controls the communication unit to perform data transmission by carrier aggregation using each channel of the first communication band and the second communication band. The communication control device according to claim 1 .

8. the control unit controls the communication unit to transmit data using one or more of a plurality of communicable channels included in the first signal in the second communication band. The communication control device according to claim 1 .

9. 1. A communication control method for controlling a communication operation of a communication unit that transmits a wireless signal by simultaneously using a first communication band and a second communication band different from the first communication band, a step of controlling the communication unit to transmit a first signal including information indicating a communication band for setting a transmission standby state (Network Allocation Vector: NAV) in a first device different from a device equipped with the communication unit, using a channel on the first communication band; the information indicating the communication band includes information indicating the second communication band; Communication control method.

10. a control unit that controls a communication operation of a communication unit that receives wireless signals transmitted by simultaneously using a first communication band and a second communication band different from the first communication band; the control unit controls the communication unit to receive, via a channel on the first communication band, a first signal including information indicating a communication band that causes a first device different from a device including the communication unit to set a transmission standby state (Network Allocation Vector: NAV) in a predetermined communication band on the second communication band; the information indicating the communication band includes information indicating the second communication band; Communications control device.

11. the control unit controls the communication unit to transmit a second signal in response to the first signal and to receive the transmitted data by simultaneously using a channel included in the first communication band and a channel included in the second communication band. The communication control device according to claim 10.

12. the information indicating the communication band further includes information indicating a third communication band different from the second communication band; The communication control device according to claim 11.

13. the second signal includes information indicating a predetermined channel included in the second communication band that causes the first device to set a transmission standby state (Network Allocation Vector: NAV); The communication control device according to claim 11.

14. the control unit controls the communication unit to return the second signal including information on a channel selected from a plurality of available channels included in information indicating the communication band of the first signal. The communication control device according to claim 11.

15. the control unit controls the communication unit to perform a receiving operation on a channel included in the second signal. The communication control device according to claim 14.

16. the information indicating the communication band of the first signal includes information regarding one available communication band; the control unit controls the communication unit to perform a receiving operation in the one communicable band. The communication control device according to claim 10.

17. the control unit controls the communication unit to receive data transmitted by carrier aggregation using each channel of the first communication band and the second communication band. The communication control device according to claim 10.

18. the control unit controls the communication unit to perform a receiving operation in one or more of a plurality of communicable bands included in the information indicating the communication band of the first signal, among the second communication bands. The communication control device according to claim 10.

19. the control unit controls the communication unit to wait for transmission in the second communication band in response to receiving the first signal addressed to another station. The communication control device according to claim 10.

20. the control unit controls the communication unit to wait for transmission in the second communication band in response to receiving the second signal addressed to another station. The communication control device according to claim 11.

21. 1. A communication control method for controlling a communication operation of a communication unit that receives wireless signals transmitted by simultaneously using a first communication band and a second communication band different from the first communication band, a step of controlling the communication unit to receive, via a channel on the first communication band, a first signal including information indicating a communication band that causes a first device different from a device equipped with the communication unit to set a transmission standby state (Network Allocation Vector: NAV) in a predetermined communication band on the second communication band; the information indicating the communication band includes information indicating the second communication band; A communication control method comprising:

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