communication control device

Abstract

To provide a communication device that performs processing for estimating out-of-band leakage power.SOLUTION: A communication apparatus includes a communication unit that transmits and receives wireless signals in a first frequency band and a second frequency band, and a control unit that controls a communication operation in the communication unit, and is configured to transmit a reference signal in the first frequency band and the second frequency band, and receive a communication result from a transmission destination of the reference signal. The control unit determines the transmission destination of the reference signal on the basis of results of exchange of capability information with the first terminal and the second terminal, and performs control such that a notification signal for notifying that the reference signal will be transmitted in advance is transmitted in the first frequency band and the second frequency band.SELECTED DRAWING: Figure 7

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 recent years, wireless communication technology has become widespread. For example, in wireless LANs (Local Area Networks) standardized by IEEE802.11 and other standards, data is transmitted wirelessly between a base station and its associated terminals. In situations where communication from a base station to multiple terminals is required, it is important to reduce interference between terminals and achieve efficient simultaneous communication with multiple terminals.

[0003] When a single base station assigns different frequency channels to multiple terminals for transmission, if the assigned spectrum densities differ between terminals, the terminal with a lower spectrum density will have a relatively lower SINR (Signal-to-Interference and Noise Power Ratio) due to out-of-band leakage of the transmitted signal to the terminal with a higher spectrum density, resulting in a problem of degraded quality of the received signal. Generally, an upper limit for out-of-band leakage is specified, but the actual out-of-band leakage power depends on the designed RF (Radio Frequency) circuit, and its characteristics change due to aging degradation, making it difficult to estimate the out-of-band leakage from the transmitter side alone.

[0004] For example, a transmission method has been proposed in which the number of subcarriers used for data transmission is changed depending on the performance of the destination device, and interference is reduced by not transmitting signals on adjacent frequency channels (see Patent Document 1).A communication system has also been proposed in which interference is reduced by lowering the power of frequency channels or the number of modulation levels (see Patent Document 2).

[0005] In addition, to address the problem of interference caused by out-of-band leakage power when multiple terminals send reception responses to a base station in the uplink, a wireless communication system has been proposed that controls the amount of interference by controlling the power of the reception responses or the transmission time (see Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-60689 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-136431 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-146988 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the technology disclosed in this specification is to provide a communication device and a communication method that operate in a communication system in which data is transmitted from a base station to a plurality of terminals using different frequency bands. [Means for solving the problem]

[0008] 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 radio signals in a first frequency band and a second frequency band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls an operation of transmitting a reference signal in the first frequency band and the second frequency band and receiving a communication result from a transmission destination of the reference signal. It is a communication device.

[0009] The control unit determines a transmission destination of the reference signal based on a result of exchanging capability information with the first terminal and the second terminal, and controls to transmit a notification signal notifying in advance that the reference signal will be transmitted in the first frequency band and the second frequency band.The control unit then controls to simultaneously perform communication with the first terminal in the first frequency band and communication with the second terminal in the second frequency band.

[0010] A second aspect of the technology disclosed in this specification is: A communication method in a communication device that transmits and receives radio signals in a first frequency band and a second frequency band, comprising: transmitting a reference signal in the first frequency band and the second frequency band; receiving a communication result from a destination of the reference signal; It is a communication method having the above.

[0011] A third aspect of the technology disclosed in this specification is: a communication unit that transmits and receives radio signals in a first frequency band and a second frequency band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit receives a reference signal in the first frequency band and the second frequency band, and controls an operation of transmitting a communication result to a transmission source of the reference signal. It is a communication device.

[0012] In response to receiving a notification signal notifying in advance that the reference signal will be transmitted, the control unit controls to receive the reference signal in the first frequency band and the second frequency band, and also controls to estimate signal qualities of the reference signals received in the first frequency band and the second frequency band and transmit the estimated signal qualities as the notification result.

[0013] Furthermore, a fourth aspect of the technology disclosed in this specification is: A communication method in a communication device that transmits and receives radio signals in a first frequency band and a second frequency band, comprising: receiving a reference signal in the first frequency band and the second frequency band; controlling an operation of transmitting a communication result to a source of the reference signal; It is a communication method having the above. [Effects of the Invention]

[0014] The technology disclosed in this specification makes it possible to provide a communication device and a communication method that perform processing to estimate out-of-band leakage power when transmitting data from a base station to multiple terminals using different frequency bands.

[0015] Furthermore, the technology disclosed in this specification can provide a communication device and a communication method that controls the modulation level and coding scheme assigned to each terminal based on the estimation result of the out-of-band leakage power.

[0016] Furthermore, according to the technology disclosed in this specification, it is possible to provide a communication device and a communication method that notify information for determining the modulation level and coding method to be assigned to each terminal, or that notify the modulation level and coding method to be assigned to each terminal.

[0017] It should be noted that the effects described in this specification are merely examples, and the effects brought about by the technology disclosed in this specification are not limited to these. Furthermore, the technology disclosed in this specification may also bring about additional effects in addition to the effects described above.

[0018] 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]

[0019] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a communication system. [Figure 2]FIG. 2 is a diagram showing an example of the configuration of the communication device 200. [Figure 3] FIG. 3 is a diagram showing the spectrum of a transmission signal when the AP simultaneously transmits to STA1 and STA2 using Band1 and Band2, respectively. [Figure 4] FIG. 4 is an enlarged view of an area where interference occurs between adjacent frequency bands. [Figure 5] FIG. 5 is a diagram showing an example of a communication sequence (first embodiment) performed between the AP and STA1 and STA2. [Figure 6] FIG. 6 is a diagram showing an example of the configuration of a capability information frame 600. [Figure 7] FIG. 7 is a diagram showing an example (first embodiment) of a sequence of frame exchange performed in the out-band sounding phase. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of a Partial Sounding Announcement frame 800. As shown in FIG. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of a P-NDP-S frame 900 (first embodiment). [Figure 10] FIG. 10 is a diagram showing an example of the configuration of a P-NDP-I frame 1000 (first embodiment). [Figure 11] FIG. 11 is a diagram showing an example of the configuration of a Feedback frame 1100. [Figure 12] FIG. 12 is a diagram showing an example of the configuration of a data frame 1200. [Figure 13] FIG. 13 is a flowchart showing a processing procedure for performing out-band sounding and data transmission in the AP. [Figure 14] FIG. 14 is a diagram showing an example of a communication sequence (second embodiment) performed between the AP and STA1 and STA2. [Figure 15] 15 is a diagram showing an example of a communication sequence (second embodiment) carried out between the AP and STA1 and STA2. [Figure 16] FIG. 16 is a diagram showing an example of the configuration of a P-NDP-S / I frame 1600 (second embodiment). DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the technology disclosed in this specification will be described in detail with reference to the drawings.

[0021] A. System Configuration FIG. 1 shows a schematic diagram of an example of the configuration of a communication system to which the technology disclosed in this specification is applied. The illustrated communication system is composed of one base station (AP) and multiple terminals (STA1, STA2) connected to the base station. Different frequency bands, Band 1 and Band 2, are available within the communication system, and the AP performs wireless communication with STA1 using Band 1 and with STA2 using Band 2. Here, Band 1 and Band 2 are adjacent frequency bands. It is also possible for three or more terminals to be connected to one base station, but only two are shown here for simplicity of explanation. The communication system may also be capable of using three or more frequency bands, including frequency bands other than Band 1 and Band 2.

[0022] FIG. 2 shows an example of the configuration of a communication device 200 that can operate as either an AP or a STA in the above communication system.

[0023] The illustrated communication device 200 includes a control unit 210, a power supply unit 220, multiple (three in the illustrated example) communication units 230-1, 230-2, and 230-3, and an antenna unit 240-1 for each communication unit 230-1. Each of the communication units 230-1, 230-2, and 230-3 is assumed to operate in a different frequency band. Since the communication system illustrated in FIG. 1 is assumed to operate in two frequency bands, Band 1 and Band 2, if the communication device 200 is an AP, it is equipped with at least two communication units 230-1 and 230-2 to perform wireless communication in both the Band 1 and Band 2 frequency bands. Furthermore, if the communication device 200 is STA1 or STA2, it may be equipped with only a communication unit corresponding to the frequency band to be used, either Band 1 or Band 2. Since the antenna section 240-1 of each communication section 230-1 and communication section 230-2, . . . has the same configuration, they will be referred to as communication section 230 and antenna section 240 below for the sake of simplicity.

[0024] Communication unit 230 is composed of a processor or circuit such as a microprocessor, and includes radio control unit 231, data processing unit 232, modulation / demodulation unit 233, signal processing unit 234, channel estimation unit 235, a plurality of wireless interface (IF) units 236-1, ..., 236-N arranged in parallel, and amplifier units 237-1, ..., 237-N connected in series to each of the wireless interface units 236-1, ..., 236-N (where N is an integer of 2 or more). Each of amplifier units 237-1, ..., 237-N is connected to each of antenna elements constituting antenna unit 240 corresponding to that communication unit 230.

[0025] One or more sets of serially connected wireless interface unit 236, amplifier unit 237, and antenna element in antenna unit 240 may be components of communication unit 230. Furthermore, each of wireless interface units 236-1, ..., 236-N may include the function of the corresponding amplifier unit 237-1, ..., 237-N.

[0026] When data is input from an upper layer of its own communication protocol during transmission, the data processing unit 232 generates a packet for wireless transmission from the data, and further performs processing such as adding a header for Media Access Control (MAC) and adding an error detection code, and provides the processed data to the modulation / demodulation unit 233. When data is received from the modulation / demodulation unit 233 during reception, the data processing unit 232 analyzes the MAC header, detects packet errors, and reorders packets, and provides the processed data to the upper layer of its own protocol.

[0027] Wireless control unit 231 controls the exchange of information between the various units within communication device 200. Wireless control unit 231 also performs parameter setting in modulation / demodulation unit 233 and signal processing unit 234, packet scheduling in data processing unit 232, and parameter setting and transmission power control in wireless interface unit 236 and amplifier unit 237.

[0028] During transmission, modem unit 233 performs encoding, interleaving, and modulation processing on input data from data processing unit 232 based on the encoding method and modulation method set by radio control unit 231, generates a data symbol stream, and provides it to signal processing unit 234. During reception, modem unit 233 performs demodulation processing, deinterleaving, and decoding processing on the input symbol stream from signal processing unit 234, which are the opposite of those during transmission, and provides the data to data processing unit 232 or radio control unit 231.

[0029] During transmission, signal processing unit 234 performs signal processing for spatial separation on input from modem unit 233 as necessary, and provides the obtained one or more transmission symbol streams to each of radio interface units 236-1, ..., 236-N. During reception, signal processing unit 234 performs signal processing on reception symbol streams input from each of radio interface units 236-1, ..., 236-N, and performs spatial decomposition of the stream as necessary before providing the result to modem unit 233.

[0030] The channel estimation unit 235 calculates complex channel gain information of the propagation path from the preamble portion and the training signal portion of the input signal from each of the radio interface units 236-1, ..., 236-N. The calculated complex channel gain information is used for demodulation processing in the modem unit 233 and spatial processing in the signal processing unit 234 via the radio control unit 231.

[0031] During transmission, the wireless interface unit 236 converts the input from the signal processing unit 234 into an analog signal, performs filtering, up-conversion to a carrier frequency, and phase control, and sends the signal to the corresponding amplifier unit 237 or antenna unit 240. During reception, the wireless interface unit 236 performs processing on the input from the corresponding amplifier unit 237 or antenna unit 240, such as down-conversion, filtering, and conversion to a digital signal, which is the opposite of that during transmission, and provides the data to the signal processing unit 234 and the channel estimation unit 235.

[0032] During transmission, amplifier unit 237 amplifies an analog signal input from wireless interface unit 236 to a predetermined power level and sends it to a corresponding antenna element in antenna unit 240. During reception, amplifier unit 237 low-noise amplifies a signal input from a corresponding antenna element in antenna unit 240 to a predetermined power level and outputs it to wireless interface unit 236.

[0033] At least one of the transmission function and the reception function of the amplifier unit 237 may be included in the wireless interface unit 236. Furthermore, at least one of the transmission function and the reception function of the amplifier unit 237 may be a component other than the communication unit 230.

[0034] A set of wireless interface unit 236 and amplifier unit 237 constitutes one RF (Radio Frequency) branch. One RF branch is capable of transmitting and receiving in one band. In the device configuration example shown in Fig. 2, communication unit 230 has N RF branches.

[0035] Control unit 210 is composed of a processor such as a microprocessor and circuits, and controls wireless control unit 231 and power supply unit 220. Control unit 210 may also perform at least a part of the above-described operations of wireless control unit 231 in place of wireless control unit 231. In particular, in this embodiment, control unit 210 and wireless control unit 231 control the operations of each unit to realize operations according to each example described below.

[0036] The power supply unit 220 is configured by a battery power supply or a fixed power supply, and supplies power to the communication device 200 for driving it.

[0037] While communication device 200 is in standby, communication unit 230 may be configured to transition to a standby state or a sleep state (or a state in which at least some functions are stopped) to reduce power consumption. In the example of the device configuration shown in FIG. 2, communication unit 230 includes N RF branches, but may be configured to transition to a standby state or a sleep state for each RF branch. However, when transmitting and receiving data using carrier aggregation, at least the RF branches corresponding to the number of bands to be aggregated must have returned to their normal operating states.

[0038] The control unit 210 and the communication unit 230 can be configured together as one or more LSIs (Large Scale Integration).

[0039] B. Simultaneous use of adjacent frequency bands FIG. 3 shows the spectrum of a transmission signal when the AP simultaneously transmits to STA1 and STA2 using Band 1 and Band 2, respectively. As described above, Band 1 and Band 2 are adjacent frequency bands. Therefore, Band 2 is affected by out-of-band leakage from Band 1, and conversely, Band 1 is affected by out-of-band leakage from Band 2. In FIG. 3, the shaded area indicated by reference numeral 301 is an area affected by interference between adjacent frequency bands. FIG. 4 also shows an enlarged view of area 301 affected by interference between adjacent frequency bands.

[0040] In general, even if the power of a transmission signal is the same, the spectrum density differs if the bandwidth used for transmission is different. In Orthogonal Frequency Division Multiplexing (OFDM) modulation, transmission data is transmitted on any subcarrier, but power leakage occurs outside the frequency band carrying the transmission data. As shown in Figures 3 and 4, when adjacent frequency bands are used in particular, interference due to leakage power increases locally near the band boundary, resulting in a smaller SINR. In Figure 4, reference numeral 401 indicates the SINR affected by out-of-band leakage, and reference numeral 402 indicates the SINR not affected by out-of-band leakage.

[0041] It is well known that power leakage to frequencies other than the desired band can be reduced by using components such as bandpass filters. However, it is difficult to accurately obtain the filter characteristics due to factors such as aging. Therefore, even in a propagation path with flat frequency characteristics, the quality of the received signal varies for each frequency band due to interference, so it is necessary to determine the optimal MCS (Modulation and Coding Scheme) for each quality of the received signal.

[0042] Therefore, this specification describes a sounding method for efficiently estimating quality degradation of a received signal due to out-of-band leakage, as well as a method for reporting an MCS determined according to the quality of the received signal. In this specification, the communication procedure for estimating the signal quality in a desired band where a desired signal is transmitted and the signal quality of an interfering signal received due to out-of-band leakage, and for providing feedback on this estimation, is referred to as "Out-Band Sounding." Furthermore, the signaling information reporting an MCS changed for each frequency is referred to as "MBO (Multi-Band Operation) SIG."

[0043] Out-band sounding uses the following frames: Partial Sounding Announcement, which notifies the STA of the start of sounding in advance from the AP; P(Partial)-NDP(Null Data Packet)-I(Interference) and P-NDP-S(Signal) or P-NDP-S / I, which are frames transmitted by the AP for signal quality estimation; and Feedback, which the STA uses to notify the AP of information regarding the MCS of the transmitted signal based on the estimation results. When the AP receives Feedback frames from multiple STAs, a separate Trigger frame may be required.

[0044] Here, P-NDP-S is a sounding frame for sounding only the desired band, P-NDP-I is a sounding frame for sounding the interference band, and P-NDP-S / I is a sounding frame for sounding both the desired band and the interference band.

[0045] By designing the signal quality estimation sequences included in P-NDP-S, P-NDP-I, and P-NDP-S / I based on the frequency range to be estimated, it is possible to shorten the frame length of these sounding frames.

[0046] Furthermore, MBO-SIG can improve the transmission rate by notifying a batch change of MCS for arbitrarily grouped subcarriers. [Example]

[0047] Fig. 5 shows an example of a communication sequence performed between the AP and STA1 and STA2 as a first embodiment. In a communication system consisting of the AP, STA1, and STA2, it is assumed that the AP performs wireless communication with STA1 using Band 1 and with STA2 using Band 2, as shown in Fig. 1. The AP, STA1, and STA2 are each equipped with the device configuration shown in Fig. 2, and perform wireless communication using Band 1 and Band 2. n It is assumed that wireless communication using d2 is possible.

[0048] The communication sequence shown in Fig. 5 mainly assumes six phases: capability exchange, association, transmission right acquisition, out-band sounding, MCS allocation determination, and data transmitting. Note that the order in which each phase is performed is not limited to the example shown in Fig. 5. For example, capability exchange may be performed after association. Furthermore, each phase does not necessarily have to be separated. For example, capability exchange and association may be performed simultaneously.

[0049] In the capability exchange phase (F510), capability information is exchanged between the AP and STA2, and between the AP and STA1. The main feature of this embodiment is that information on whether out-band sounding is executable is exchanged between the AP and STA1 and STA2. Details of the capability information exchanged between the AP and STA1 and STA2, and details of the frames used to exchange capability information will be described later.

[0050] In the association phase (F520), connection processing is completed between the AP and STA1, and between the AP and STA2. Association is performed, for example, in accordance with the IEEE 802.11 standard, by an association request from each of STA1 and STA2 and an association response from the AP.

[0051] In the transmission right acquisition phase (F530), an agreement is formed between the AP and STA1 and STA2 to transmit data from the AP to STA1 and STA2. For example, the AP may acquire the transmission right in accordance with CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance).

[0052] In the Out-band Sounding phase (F540), the AP transmits signal quality estimation frames to STA1 and STA2, and feedback is provided from STA1 and STA2. Specifically, when the AP simultaneously transmits to STA1 and STA2 using Band1 and Band2, STA1 estimates the out-of-band leakage power in the desired band (Band1) based on the signal quality estimation frame, and notifies the AP in a Feedback frame of information that enables the AP to determine an MCS that can be received with the desired quality in Band1 based on the estimation result. STA2 also estimates the out-of-band leakage power in the desired band (Band2) based on the signal quality estimation frame, and notifies the AP in a Feedback frame of information that enables the AP to determine an MCS that can be received with the desired quality in Band2 based on the estimation result. The information that STA1 and STA2 notify the AP of may be, for example, information specifying the transmission rate, such as SINR. Details of the Out-band Sounding phase in this embodiment will be described later.

[0053] It is preferable that the out-band sounding phase is always performed before determining MCS allocation, but if the AP determines that it is not necessary to perform it every time before determining MCS allocation, it may be omitted.

[0054] In the MCS allocation determination phase (F550), the AP determines the MCS for the signals that the AP will transmit to each of STA1 and STA2 in the subsequent data transmission phase (F560) for each subcarrier or grouped subcarriers (in other words, for each frequency resource block) based on the information notified in the feedback frame from STA1 and STA2 in the out-band sounding phase (F540).

[0055] In the data transmission phase (F560), data is transmitted from the AP to STA1 and STA2 using the MCS determined in the MCS assignment determination phase (F550). Prior to data transmission (specifically, by MBO-SIG in the header of the data frame), the MCS to be used is notified to each of STA1 and STA2. In this notification, the MCS is notified for each subcarrier or for each group of subcarriers.

[0056] FIG. 6 shows an example of the structure of a capability information frame 600 used for exchanging capability information in the capability exchange phase (F510).

[0057] The Timestamp field indicated by reference number 601 stores information for achieving time synchronization between transmission and reception of the frame.

[0058] The BSSID field indicated by reference number 602 stores identification information of the BSS (Basic Service Set) to which the communication terminal that is the sender of the frame belongs.

[0059] The OB Sounding field denoted by reference number 603 stores information indicating whether the communication terminal that transmitted the frame is capable of performing out-band sounding and the frame length for channel estimation that can be transmitted and received in out-band sounding. Here, the frame length for channel estimation that can be transmitted and received does not need to be uniquely determined, and may instead indicate, for example, that three types are available for transmission and two types are available for reception.

[0060] 7 shows an example of a frame exchange sequence performed in the Out-band Sounding phase (F540) in this embodiment. The horizontal axis represents time. Each square box represents a frame transmitted by the AP or STA1 in the frequency band (Band 1 or Band 2) corresponding to the horizontal axis, and the arrow extending from each box indicates the destination of the frame.

[0061] In the Out-band Sounding phase (F540), three types of frames, Partial Sounding Announcement, P-NDP-S, and P-NDP-I, are transmitted from the AP to STA1, and then a Feedback frame is returned from STA1 to the AP.

[0062] To notify STA1 of the start of sounding, the AP transmits a Partial Sounding Announcement frame on Band 1, which is the desired band used for data transmission to STA1. The Partial Sounding Announcement frame contains information about the signal quality estimation frames (P-NDP-S, P-NDP-I) ​​that will be transmitted immediately afterwards.

[0063] Next, the AP transmits a P-NDP-S frame on Band 1 for STA1 to estimate the received signal quality in Band 1, which is the desired band. STA1 may use the P-NDP-S frame to estimate the received power of the desired signal.

[0064] Next, the AP transmits a P-NDP-I frame on Band 2 to allow STA1 to estimate the received signal quality in the interference band, Band 2. STA1 uses the P-NDP-I frame to estimate the received power of the signal leaking out of the band from Band 2 to Band 1.

[0065] In the frame exchange sequence example shown in Fig. 7, after the Partial Sounding Announcement frame, P-NDP-S and P-NDP-I are transmitted in this order, but this order does not have to be exact. Also, P-NDP-S and P-NDP-I (in other words, soundings that estimate the received power of the desired signal and the received power of the leakage signal) may be transmitted together as a single frame.

[0066] STA1 estimates the signal quality of the desired signal and the leakage signal using the P-NDP-S and P-NDP-I frames, and sends a Feedback frame containing information based on the estimation results back to the AP over the desired band, Band 1. The Feedback frame contains information about the MCS to be set when the AP allocates Band 1 to STA1 when transmitting wireless signals simultaneously over Band 1 and Band 2 (or information that can determine the MCS).

[0067] In this specification, sounding of out-of-band leakage signals from adjacent bands into the desired band is also referred to as "partial sounding." If the AP determines that it can use information obtained in a feedback frame for a previous partial sounding, it may determine an MCS based on the information obtained in the previous feedback frame and perform data transmission without performing partial sounding. On the other hand, if the AP fails to receive a feedback frame from STA1 after performing partial sounding, it may request STA1 to retransmit.

[0068] Although FIG. 7 illustrates only the frame exchange sequence between the AP and STA1, it is assumed that a similar frame exchange sequence is also performed between the AP and STA2 in the Out-band Sounding phase (F540).

[0069] 8 shows an example of the configuration of a Partial Sounding Announcement frame 800. The frame 800 is used by the AP to notify the STA of the start of out-band sounding.

[0070] Information indicating that the frame is a Partial Sounding Announcement is stored in a Frame Control field denoted by reference number 801. Information indicating the length of the frame is stored in a Duration / ID field denoted by reference number 802.

[0071] The RA field indicated by reference number 803 stores information (Receiver Address) that identifies the STA that is the destination of the frame, and the TA field indicated by reference number 804 stores information (Transmitter Address) that identifies the AP that is the source of the frame. For example, MAC addresses are used as information that identifies the destination and source communication terminals.

[0072] The Sounding Bands field denoted by reference number 805 stores information indicating the order and frequency band in which subsequent P-NDP frames are transmitted. The order in which P-NDP frames are transmitted may be information indicating the transmission start time.

[0073] 8, the Sounding Bands field 805 includes fields Channel Band1, Channel Band2, ..., Channel BandN, designated by reference numerals 805-1, 805-2, ..., 805-N, respectively. The Channel Band1 field 805-1 stores information about the frequency band in which each of the P-NDP-S and P-NDP-I sounding frames will be transmitted immediately after the Partial Sounding Announcement frame 800. Similarly, the Channel Band2 stores information about the frequency band in which each of the P-NDP-S and P-NDP-I sounding frames will be transmitted immediately thereafter. Each of the Channel Band fields 805-1, 805-2, ..., 805-N stores information indicating, for example, the transmission start time and transmission order of the corresponding sounding frame, and the type of P-NDP-S and P-NDP-I (whether the sounding frame is for a desired signal or an out-of-band interference signal).

[0074] A Sounding Dialog Token field indicated by reference number 806 stores the time of the sounding or information that enables the AP to distinguish it from other Partial Sounds.

[0075] 9 shows an example of the configuration of a P-NDP-S frame 900. The frame 900 is transmitted by the AP so that the receiving STA can estimate the quality of the received signal (or the received power of the desired signal) in the desired band (Band 1 in the example shown in FIG. 7).

[0076] An STF (Short Training Field) field indicated by reference number 901 stores information (for example, a known signal sequence) that a communication terminal that receives the frame 900 uses for time synchronization and frequency synchronization.

[0077] The P-LTF (Partial-Long Training Sequence) field indicated by reference number 902 stores information (e.g., a reference signal consisting of a known signal sequence) that a communication terminal receiving the frame 900 uses to estimate the quality of the received signal (P-NDP-S) in the desired band.

[0078] Here, the P-LTF may include information that allows the quality of only a portion of frequencies to be estimated in signal quality estimation in a desired band (Band1 in the example shown in FIG. 7). That is, the frame length of the P-LTF may be dynamically changed so that the signal quality of only a portion of the frequency band in Band1 (or Band2) can be estimated. In particular, when the frequency for which the signal quality is to be estimated is a plurality of consecutive subcarriers, the P-LTF may be changed to a field length shorter than that of the STF (in the example shown in FIG. 9, the STF field 901 is 64 bits long, while the P-LTF field 902 is 16 bits long). For example, when the subcarrier number k takes the values ​​of k=−32, −31, ..., 31, and it is desired to estimate the signal quality of only 16 subcarriers with −32≦k≦−25, a sequence L1(s) according to the following equations (1) and (2) may be used. Here, s is the sample number in the P-LTF, and L1(s) consists of 16 samples (s=0, 1, ..., 15).

[0079]

number

[0080]

number

[0081] Furthermore, when the subcarrier number k takes the values ​​of k=-64, -63, ..., 63, if it is desired to estimate the signal quality of only eight subcarriers where 56≦k≦63, the sequence L2(s) according to the following equations (3) and (4) may be used, where s is the sample number within the P-LTF, and L2(s) consists of 16 samples (s=0, 1, ..., 7).

[0082]

number

[0083]

number

[0084] Fig. 10 shows an example of the configuration of a P-NDP-I frame 1000. The frame 900 is transmitted by the AP so that the receiving STA can estimate the quality of a signal (or the received power of an interfering signal) leaking into the desired band from a band adjacent to the desired band (Band 2 in the example shown in Fig. 7).

[0085] The STF1 field indicated by reference number 1001 stores information used for time synchronization and frequency synchronization by a communication terminal that receives the frame 1000 in Band 1. The STF2 field indicated by reference number 1002 stores information used for time synchronization and frequency synchronization by a communication terminal that receives the frame 1000 in Band 2.

[0086] The P-LTF field denoted by reference number 1003 stores information used by a communication terminal that receives the frame 1000 in Band 2 to estimate the quality of an interference signal (P-NDP-I) ​​leaking from an adjacent band into the desired band. The P-LTF field 1003 may use a known signal sequence similar to that of the P-LTF field 902 of the P-NDP-S frame 900.

[0087] 11 shows an example of the configuration of a Feedback frame 1100. The frame 1100 is used by a STA to feed back to an AP the results of estimating the signal qualities of the desired signal and the leakage signal using the P-NDP-S and P-NDP-I frames, or information based on the estimation results.

[0088] Information indicating that the frame is a Partial Sounding Announcement is stored in a Frame Control field denoted by reference number 1101. Information indicating the length of the frame is stored in a Duration / ID field denoted by reference number 1102.

[0089] The RA field indicated by reference number 1103 stores information identifying the AP to which the frame is to be sent, and the TA field indicated by reference number 1104 stores information identifying the STA that is the source of the frame. MAC addresses, for example, are used as information to identify the destination and source communication terminals.

[0090] An OB (Outband) Control field denoted by reference number 1105 includes fields for Channel Width, Grouping, Coefficient Size, and Signal Level denoted by reference numbers 1111 to 1114, respectively.

[0091] The Channel Width field 1111 includes information indicating the frequency band in which the frame 1100 should be transmitted. The Signal Level field 1114 stores information indicating, for each subcarrier, information for determining the MCS to be set when the AP to which the frame 1100 is returned transmits data to the STA that returned the frame 1100. The Signal Level field 1114 stores, for example, the received signal level of the P-NDP-S in each subcarrier, the ratio of the received signal levels between the P-NDP-S and P-NDP-I, etc.

[0092] The Signal Level field 1114 does not necessarily need to store information for all subcarriers, and may store, for example, only information thinned out at a predetermined interval. When the information is thinned out, the Grouping field 1112 stores information indicating which subcarrier information is stored in the Signal Level field.

[0093] The Coefficient Size field 1113 stores information indicating the accuracy and resolution of the information stored in the Signal Level field 1114 .

[0094] 12 shows an example of the configuration of a data frame 1200. The frame 1200 is used when transmitting data from an AP to a STA in the data transmission phase (F560).

[0095] An L (Legacy)-STF field indicated by reference number 1201 stores information that a communication terminal that receives the frame 1200 uses for time synchronization and frequency synchronization.

[0096] The L-LTF field indicated by reference number 1202 stores a reference signal consisting of information for estimating a propagation path between the communication terminal that received the frame 1200 and the source of the frame 1200. Note that the L-LTF field 1202 may store information used for time synchronization and frequency synchronization, similar to the L-STF.

[0097] The L-SIG field indicated by reference number 1203 stores information indicating the length of the data portion following the field 1203, etc.

[0098] It is assumed that the L-STF field 1201, the L-LTF field 1203, and the L-SIG field 1203 are transmitted simultaneously in Band 1 and Band 2. They may also be transmitted in other frequency bands available in the communication system.

[0099] The MBO SIG field denoted by reference numeral 1204 stores information indicating the frequency band and MCS in which data signals to the following STA1 and STA2 are transmitted. The MBO SIG field 1204 stores information on STA1 and STA2 in Band1 and Band2, respectively, but may also store information on both STA1 and STA2.

[0100] The MBO SIG field 1204 is configured to indicate the MCS set for each subcarrier or for each group of subcarriers (in other words, for each frequency resource block). The information included in the MBO SIG field 1204 will be described below.

[0101] A Num Gp field denoted by reference number 1211 stores information indicating the number of divisions into which the frequency band used for transmitting the frame 1200 is divided. In the example shown in Fig. 12, the frequency band is divided into M groups (where M is an integer equal to or greater than 1).

[0102] Each frame of MCS_1, ..., MCS_M, indicated by reference numbers 1212-1, ..., 1212-M, respectively, stores information indicating the optimal MCS (modulation multi-level number and coding method) to be used when transmitting data for each of M groups obtained by dividing the frequency band.

[0103] The Tone_1 START and Tone_1 END fields, designated by reference numerals 1213-1 and 1214-1, respectively, store information indicating the frequency band of the first group obtained by dividing the frequency band into M parts. For example, if different subcarrier numbers are assigned in order for each subcarrier to be used, information indicating the first subcarrier number and the last subcarrier number of the first group (including the lowest frequency) is stored in the Tone_1 START field 1213-1 and the Tone_1 END field 1214-1, respectively.

[0104] In addition, the Tone_M START and Tone_M END fields, designated by reference numbers 1213-M and 1214-M, respectively, store information indicating the frequency band of the Mth group obtained by dividing the frequency band into M parts, for example, the first subcarrier number and the last subcarrier number of the Mth group (including the highest frequency), in the Tone_M START field 1213-M and the Tone_M END field 1214-M, respectively.

[0105] However, if the frequency band is divided equally into fixed sizes (i.e., the same number of subcarriers), the Tone_1 START field 1213-1 and Tone_1 END field 1214-1, ..., the Tone_M START field 1213-M and Tone_M END field 1214-M are unnecessary.

[0106] Although the L-STF field 1201, the L-LTF field 1203, and the L-SIG field 1203 are transmitted simultaneously in Band 1 and Band 2, they may also be transmitted in a frequency band that can be used in common by STA1 and STA2.

[0107] A signal transmitted from the AP to STA1 and STA2 is stored in a DATA field indicated by reference number 1205. The DATA field 1205 is simultaneously transmitted in both frequency bands, Band1 and Band2, but the DATA field 1205 in Band1 contains information for STA1, and the DATA field 1205 in Band2 contains information for STA2.

[0108] 13 is a flowchart showing a processing procedure for performing out-band sounding and data transmission in an AP. This processing procedure is assumed to be executed under the overall control of control unit 210 of communication device 200 operating as an AP, for example.

[0109] The AP has exchanged capability information with the STA in the preceding capability exchange phase (F510). First, the AP checks whether it is possible to perform out-band sounding with the target STA based on the information in the OB Sounding field of the capability information frame (see FIG. 6) received from the target STA (step S1301).

[0110] If out-band sounding cannot be performed (No in step S1301), the AP does not perform out-band sounding, but instead transmits a DATA frame (see FIG. 12) with an MBO SIG attached to the STA (step S1305), and terminates this process.

[0111] On the other hand, if out-band sounding can be performed (Yes in step S1301), the AP further checks whether to use information in the feedback frame previously received from the target STA (step S1302).

[0112] If the information of the previously received Feedback frame is to be used (Yes in step S1302), the AP does not perform Out-band Sounding, but transmits a DATA frame (see FIG. 12) with an MBO SIG attached to the STA (step S1305), and terminates this process.

[0113] If the information of the previously received feedback frame is not to be used (No in step S1302), the AP executes out-band sounding with the target STA (step S1303).

[0114] The AP performs out-band sounding, for example, according to the communication sequence shown in Fig. 7. That is, after transmitting a Partial Sounding Announcement frame to the target STA, the AP transmits sounding P-NDP-S and P-NDP-I frames in any order.

[0115] Thereafter, when the AP receives a Feedback frame from the target STA (Yes in step S1304), it determines the MCS of the signal to be transmitted to the STA for each subcarrier or for each group of subcarriers based on the information contained in the Feedback frame.The AP then transmits to the STA a DATA frame (see FIG. 12) to which an MBO SIG containing information on the MCS determined for each subcarrier or for each group of subcarriers has been added (step S1305), and ends this process.

[0116] Furthermore, if the AP does not receive a Feedback frame from the target STA (No in step S1304), it requests feedback from that STA (step S1306) until it receives a Feedback frame (No in step S1307).

[0117] Then, when the AP receives a Feedback frame from the STA in response to a feedback request (Yes in step S1304), it determines the MCS of the signal to be transmitted to the STA for each subcarrier or for each group of subcarriers based on the information contained in the Feedback frame, and transmits a DATA frame (see Figure 12) with an MBO SIG attached to it to the STA (step S1305), thereby completing this process.

[0118] In the first embodiment, when a STA estimates the SINR in a communication environment where interference due to out-of-band leakage exists, the estimation frames (P-NDP-S, P-NDP-I) ​​are continuously transmitted in different frequency bands (Band 1, Band 2), thereby shortening the time required for estimation and suppressing the reduction in the effective rate due to estimation.

[0119] In the first embodiment, when estimating the SINR of only the frequencies that are subject to interference due to out-of-band leakage, the SINR estimation time can be shortened by using frames (P-NDP-S, P-NDP-I) ​​with shortened estimation sequences, and the reduction in effective rate due to estimation can be suppressed.

[0120] In the first embodiment, even when transmitting data in a communication environment where interference due to out-of-band leakage exists, the capacity of the communication system can be optimized by applying an optimal modulation level and coding scheme for each subcarrier. In this case, the modulation level and coding scheme to be changed or notified can be applied at an appropriate granularity, such as to grouped subcarriers, rather than for each subcarrier, thereby suppressing a decrease in the effective rate due to an increase in overhead. [Example]

[0121] Fig. 14 shows an example of a communication sequence performed between the AP and STA1 and STA2 as a second embodiment. In a communication system consisting of the AP, STA1, and STA2, it is assumed that the AP performs wireless communication with STA1 using Band 1 and with STA2 using Band 2, as shown in Fig. 1. The AP, STA1, and STA2 are each equipped with the device configuration shown in Fig. 2, and perform wireless communication using Band 1 and Band 2. n It is assumed that wireless communication using d2 is possible.

[0122] The communication sequence shown in Fig. 14 assumes six phases, namely, capability exchange, association, transmission right acquisition, out-band sounding, MCS allocation determination, and data transmitting, as in the first embodiment. Note that the order in which each phase is performed is not limited to the example shown in Fig. 14. For example, capability exchange may be performed after association. Furthermore, each phase does not necessarily have to be separated. For example, capability exchange and association may be performed simultaneously.

[0123] In the capability exchange phase (F1410), the AP and STA2, and the AP and STA1 exchange their capability information, including information on whether out-band sounding is possible or not (same as above).

[0124] In the association phase (F1420), connection processing is completed between the AP and STA1 and between the AP and STA2 by, for example, an association request and an association response in accordance with IEEE802.11 (same as above).

[0125] In the transmission right acquisition phase (F1430), the AP acquires the transmission right, for example, in accordance with CSMA / CA, and an agreement is formed between the AP and STA1 and STA2 to transmit data from the AP to STA1 and STA2 (same as above).

[0126] In the Out-band Sounding phase (F1440), the AP transmits frames for signal quality estimation to STA1 and STA2, and feedback is performed from STA1 and STA2. When the AP simultaneously transmits to STA1 and STA2 using Band1 and Band2, STA1 and STA2 each estimate the out-of-band leakage power in the desired band based on the signal quality estimation frames. The AP then transmits a Trigger frame on the desired bands, Band1 and Band2, of STA1 and STA2, including information on the timing at which STA1 and STA2 will transmit Feedback frames. STA1 and STA2 then feed back information to the AP, at the timing indicated in the Trigger frame, that allows them to determine the MCS that can be received with the desired quality in Band1 based on their respective estimation results. Details of the Out-band Sounding phase in this embodiment will be described later.

[0127] In the MCS allocation determination phase (F1450), the AP determines the MCS for the signals that the AP will transmit to each of STA1 and STA2 in the subsequent data transmission phase (F1460) for each subcarrier or for each group of subcarriers, based on the information notified by STA1 and STA2 in the out-band sounding phase (F1440).

[0128] In the data transmission phase (F1460), data is transmitted from the AP to STA1 and STA2 using the MCS determined in the MCS allocation determination phase (F1450). Prior to data transmission (specifically, by MBO-SIG in the header of the data frame), the MCS to be used is notified to each of STA1 and STA2. In this notification, the MCS is notified for each subcarrier or for each group of subcarriers.

[0129] 15 shows an example of a frame exchange sequence performed in the Out-band Sounding phase (F1440) in this embodiment. The horizontal axis represents the time axis. Each square box represents a frame transmitted by the AP or STA1 in the frequency band (Band 1 or Band 2) corresponding to the horizontal axis, and the arrow extending from each box indicates the destination of the frame.

[0130] In the Out-band Sounding phase (F1440), three types of frames are transmitted from the AP to STA1: Partial Sounding Announcement, P-NDP-S / I, and Trigger, and then a Feedback frame is returned from STA1 to the AP.

[0131] The AP transmits a Partial Sounding Announcement frame on Band 1, which is the desired band of STA1, and also transmits a Partial Sounding Announcement frame on Band 2, which is the desired band of STA2, to notify the start of sounding.

[0132] The configuration of the Partial Sounding Announcement frame may be the same as that of the first embodiment (see FIG. 8). The Partial Sounding Announcement frame includes information about the P-NDP-S / I frame for signal quality estimation that will be transmitted immediately afterwards.

[0133] Next, the AP transmits P-NDP-S / I frames on Band 1 and Band 2, which are the desired bands of STA 1 and STA 2, respectively. STA 1 estimates the received power of the desired signal based on the P-NDP-S / I frame received on Band 1, and also estimates the received power of signals leaking out of band from Band 2 to Band 1 based on the P-NDP-S / I frame received on Band 2. Similarly, STA 2 estimates the received power of the desired signal based on the P-NDP-S / I frame received on Band 2, and also estimates the received power of signals leaking out of band from Band 1 to Band 2 based on the P-NDP-S / I frame received on Band 1.

[0134] Next, the AP transmits a Trigger frame containing information about the timing at which STA1 and STA2 transmit Feedback frames on the desired bands Band1 and Band2 of STA1 and STA2, respectively. However, information about the timing at which Feedback frames are transmitted may be stored in the immediately preceding P-NDP-S / I frame instead of the Trigger frame.

[0135] STA1 and STA2 use the P-NDP-S / I frame to generate a Feedback frame that stores information based on the results of estimating the signal quality of the desired signal and the leakage signal. The configuration of the Feedback frame may be the same as in the first embodiment (see FIG. 11). STA1 and STA2 then return the Feedback frame to the AP on their respective desired bands, Band1 and Band2, at the timing indicated by the Trigger frame.

[0136] FIG. 16 shows an example of the configuration of a P-NDP-S / I frame 1600.

[0137] The STF1 field indicated by reference number 1601 stores information used for time synchronization and frequency synchronization by a communication terminal that receives the frame 1600 in Band 1. The STF2 field indicated by reference number 1602 stores information used for time synchronization and frequency synchronization by a communication terminal that receives the frame 1600 in Band 2.

[0138] The P-LTF field indicated by reference number 1603 stores information used by a communication terminal that receives frame 1600 in Band 2 to estimate the signal quality of the desired band (provided that the communication terminal has Band 2 as its desired band) or to estimate the quality of interference signals leaking from adjacent bands into the desired band (provided that the communication terminal has Band 1 as its desired band).

[0139] In addition, the P-LTF field indicated by reference number 1604 stores information used by a communication terminal that receives frame 1600 in Band 1 to estimate the signal quality of the desired band (provided that the communication terminal has Band 1 as its desired band) or to estimate the quality of an interference signal leaking from an adjacent band into the desired band (provided that the communication terminal has Band 2 as its desired band).

[0140] The P-LTF fields 1603 and 1604 may use a known signal sequence similar to that of the P-LTF field 902 of the P-NDP-S frame 900 in the first embodiment.

[0141] Also, similar to the first embodiment, the P-LTF fields 1603 and 1604 may include information that allows only partial frequency quality to be estimated in signal quality estimation in Band 1 and Band 2, respectively. That is, the field lengths of the P-LTF fields 1603 and 1604 may be dynamically changed so that the signal quality of only a partial frequency band in each of Band 1 and Band 2 can be estimated.

[0142] The order in which P-LTFs are transmitted for each frequency band is not limited to the example shown in Fig. 16. Information indicating the order in which P-LTFs are transmitted for each frequency band may be notified to each STA using, for example, a Partial Sounding Announcement frame.

[0143] In the second embodiment as well, in a communication environment where interference due to out-of-band leakage exists, the time required for signal quality estimation is shortened, thereby making it possible to suppress a decrease in effective rate due to estimation.Furthermore, in the second embodiment as well, the capacity of the communication system can be optimized by applying an optimal modulation level and coding scheme for each subcarrier during data transmission in a communication environment where interference due to out-of-band leakage exists.

[0144] In the first embodiment, two types of sounding frames, P-NDP-S and P-NDP-I, are used, and sounding is performed separately for each of STA1 and STA2 (i.e., for each STA with a different desired band). In contrast, in the second embodiment, one type of sounding frame, P-NDP-S / I, is used, and sounding is performed simultaneously for both STA1 and STA2 (i.e., all STAs with different desired bands), so the time required for sounding can be shortened. However, it is necessary to notify STA1 and STA2 of the timing to transmit a Feedback frame using a Trigger frame or the like. [Industrial Applicability]

[0145] 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.

[0146] The technology disclosed in this specification can be applied to communication systems that comply with the IEEE802.11 standard, for example, but can also be applied to various types of multi-band communication systems that comply with other wireless standards.

[0147] 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.

[0148] The technology disclosed in this specification can also be configured as follows.

[0149] (1) a communication unit that transmits and receives radio signals in a first frequency band and a second frequency band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit controls an operation of transmitting a reference signal in the first frequency band and the second frequency band and receiving a communication result from a transmission destination of the reference signal. Communication equipment.

[0150] (2) the control unit controls communication with a first terminal in the first frequency band and communication with a second terminal in the second frequency band to be performed simultaneously; The communication device according to (1) above.

[0151] (3) The control unit determines a transmission destination of the reference signal based on a result of exchanging capability information with the first terminal and the second terminal. The communication device according to (2) above.

[0152] (4) The control unit controls a notification signal that notifies in advance that the reference signal will be transmitted to be transmitted in the first frequency band and the second frequency band. A communication device according to any one of (1) to (3) above.

[0153] (5) The control unit controls to transmit the notification signal including at least one of a transmission time or a transmission order of the reference signals in the first frequency band and the second frequency band. The communication device according to (4) above.

[0154] (6) The control unit dynamically changes the length of the reference signal so that signal quality of only a part of the first frequency band and the second frequency band can be estimated. A communication device according to any one of (1) to (5) above.

[0155] (7) The notification result includes information for determining the modulation level and the coding method when transmitting data to the destination. A communication device according to any one of (1) to (6) above.

[0156] (8) The control unit determines a modulation level and a coding method for each frequency resource block when transmitting data to the destination. A communication device according to any one of (1) to (7) above.

[0157] (9) The control unit notifies information about the modulation level and the coding method determined for each frequency resource block in a data frame. The communication device according to (8) above.

[0158] (10) A communication method in a communication device that transmits and receives radio signals in a first frequency band and a second frequency band, comprising: transmitting a reference signal in the first frequency band and the second frequency band; receiving a communication result from a destination of the reference signal; A communication method comprising:

[0159] (10-1) The notification result includes information for determining a modulation level and an encoding method when transmitting data to the destination. The communication method according to (10) above.

[0160] (10-2) Further comprising a step of determining a modulation level and a coding scheme for each frequency resource block when transmitting data to the destination. The communication method according to (10) above.

[0161] (10-3) further comprising a step of transmitting a data frame including information on the modulation level and the coding scheme determined for each frequency resource block; The communication method according to (10) above.

[0162] (11) A communication unit that transmits and receives wireless signals in a first frequency band and a second frequency band; a control unit that controls a communication operation in the communication unit; Equipped with the control unit receives a reference signal in the first frequency band and the second frequency band, and controls an operation of transmitting a communication result to a transmission source of the reference signal. Communication equipment.

[0163] (12) In response to receiving a notification signal notifying in advance that the reference signal will be transmitted, the control unit controls to receive the reference signal in the first frequency band and the second frequency band. The communication device according to (11) above.

[0164] (13) The control unit estimates signal qualities of the reference signals received in the first frequency band and the second frequency band, and controls to transmit the notification result based on the estimation result. The communication device according to any one of (11) and (12) above.

[0165] (14) The control unit controls the communication device to transmit the notification result including information for determining a modulation level and an encoding method when transmitting data. A communication device according to any one of (11) to (13) above.

[0166] (15) The control unit controls an operation of receiving a data frame from a transmission source of the reference signal. A communication device according to any one of (11) to (14) above.

[0167] (16) The data frame includes information on a modulation level and a coding method for each frequency resource block. The communication device according to (15) above.

[0168] (17) A communication method in a communication device that transmits and receives radio signals in a first frequency band and a second frequency band, comprising: receiving a reference signal in the first frequency band and the second frequency band; controlling an operation of transmitting a communication result to a source of the reference signal; A communication method comprising:

[0169] (17-1) receiving the reference signal in the first frequency band and the second frequency band in response to receiving a notification signal notifying in advance that the reference signal will be transmitted; The communication method according to (17) above.

[0170] (17-2) Estimating signal qualities of the reference signals received in the first frequency band and the second frequency band, and transmitting the estimation result as the notification result. The communication method according to (17) above.

[0171] (17-3) Transmitting the notification result including information for determining the modulation level and coding method when transmitting data to the communication device. The communication method according to (17) above.

[0172] (17-4) further comprising a step of receiving a data frame from a source of the reference signal; The communication method according to (17) above. [Explanation of symbols]

[0173] 200...communication device, 210...control unit, 220...power supply unit 230...communication unit, 231...wireless control unit, 232...data processing unit 233...modulation / demodulation unit, 234...signal processing unit, 235...channel estimation unit 236...wireless interface unit, 237...amplifier unit 240...Antenna section

Claims

1. A method for receiving a third wireless signal based on a first wireless signal transmitted in a first frequency band from a first communication unit provided in any one of a plurality of terminals; receiving a fourth wireless signal based on a second wireless signal transmitted in a second frequency band from a second communication unit included in any one of the plurality of terminals; determining a first modulation and coding scheme (MCS) for transmitting a radio signal in the first frequency band based on the third radio signal; determining a second modulation and coding scheme for transmitting radio signals in the second frequency band based on the fourth radio signal; transmitting a fifth radio signal in the first frequency band, the fifth radio signal including first information related to the first modulation and coding method; transmitting a sixth radio signal in the second frequency band, the sixth radio signal including second information relating to the second modulation and coding method; a control unit that controls the wireless communication unit as follows: a first timing for transmitting the fifth radio signal and a second timing for transmitting the sixth radio signal are identical to each other; Communications control device.

2. the fifth radio signal includes a first data frame; the sixth radio signal includes a second data frame; The communication control device according to claim 1 .

3. The control unit transmitting the fifth radio signal based on the first modulation and coding method; transmitting the sixth radio signal based on the second modulation and coding method; The communication control device according to claim 2 , wherein the wireless communication unit is controlled so as to:

4. The control unit transmitting the fifth wireless signal to a first wireless communication device; transmitting the sixth wireless signal to a second wireless communication device; The communication control device according to claim 1 , wherein the wireless communication unit is controlled so as to:

5. The control unit receiving a seventh radio signal including an acknowledgment to the fifth radio signal; receiving an eighth wireless signal including an acknowledgment to the sixth wireless signal; and controlling the wireless communication unit so that a third timing associated with receiving the seventh radio signal and a fourth timing associated with receiving the eighth radio signal coincide with each other; The communication control device according to claim 1 .

6. The communication control device according to claim 5 , wherein the control unit controls the wireless communication unit to simultaneously transmit the fifth wireless signal and the sixth wireless signal.

7. The communication control device according to claim 6 , wherein the control unit controls the wireless communication unit to simultaneously receive the seventh wireless signal and the eighth wireless signal.

8. the fifth radio signal includes the first information associated with a first subcarrier group; The communication control device according to claim 1 .

9. the fifth radio signal further includes third information relating to a third modulation and coding method, the third information being associated with a second subcarrier group; The communication control device according to claim 8.

10. The control unit transmitting a first notification signal notifying transmission of the first radio signal in the first frequency band prior to transmission of the first radio signal; transmitting a second notification signal notifying transmission of the second radio signal in the second frequency band prior to transmission of the second radio signal; The communication control device according to claim 1 , wherein the wireless communication unit is controlled so as to:

11. the first notification signal includes at least one of a transmission time or a transmission sequence of the first wireless signal; the second notification signal includes at least one of a transmission time or a transmission sequence of the second wireless signal; The communication control device according to claim 10.

12. The control unit dynamically varying a length of the first wireless signal to estimate a signal quality of a portion of the first frequency band; dynamically varying a length of the second wireless signal to estimate a signal quality of a portion of the second frequency band; The communication control device according to claim 1 , wherein the wireless communication unit is controlled so as to:

13. A wireless communication device transmits a second wireless signal based on a first wireless signal received in the first frequency band among wireless signals transmitted by the wireless communication device in a first frequency band and a second frequency band, a third radio signal including information on a modulation and coding scheme (MCS) for receiving a radio signal in the first frequency band determined by information based on the second radio signal, and a fourth radio signal including second information on a second modulation and coding scheme for transmitting a radio signal in the second frequency band, the fourth radio signal being simultaneously transmitted by the radio communication device; and receiving the third radio signal from the radio communication device in the first frequency band. a control unit that controls the wireless communication unit so that Communications control device.

14. the third radio signal includes a data frame; The communication control device according to claim 13.

15. the control unit controls the wireless communication unit to receive the third wireless signal from the wireless communication device based on the modulation and coding method. The communication control device according to claim 13.

16. the control unit controls the wireless communication unit to transmit a fourth signal including an acknowledgement of the third wireless signal to the wireless communication device at a third timing. The communication control device according to claim 13.

17. the third radio signal includes information related to a subcarrier group; The communication control device according to claim 13.

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