JP2019145950A - Radio communication system transmitting frame and radio communication control method - Google Patents

Abstract

To determine whether a data transmission using a plurality of frequency bands at the same time is executed without deteriorating a throughput.SOLUTION: A radio communication system transfers a frame to a second radio communication device from a first radio communication device by using one or a plurality of frequency bands. The first radio communication device comprises: a plurality of transmission circuits which are provided to each frequency band, and transmit the frame containing a legacy signal field; and a signal field setting part which sets the same value to the legacy signal field of the frame transferred by using each frequency band when transmitting data by using the plurality of frequency bands at the same time. The second radio communication device comprises a determination part which determines whether a data transmission using the plurality of frequency bands at the same time is performed on the basis of a result of a comparison of the legacy signal field of the frame received through each frequency band.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a radio communication system and a radio communication control method for transmitting a frame using one or a plurality of frequency bands.

  In recent years, wireless communication systems have become widespread. For example, in a wireless LAN defined by IEEE 802.11, data is transmitted using a 5 GHz band and / or a 2.4 GHz band. The data signal is transmitted by, for example, OFDM (orthogonal frequency division multiplexing). OFDM transmits data using a plurality of subcarriers orthogonal to each other in the frequency domain.

  In wireless LAN, new standards are proposed one after another and put into practical use. However, the new wireless LAN system is required to be able to be connected to a wireless LAN system (that is, a legacy system) that has been put into practical use in the past. That is, legacy compatibility is required.

  In addition, a method for transmitting data using a plurality of frequency bands simultaneously has been proposed. And even if it is a wireless LAN which transmits data using a plurality of frequency bands at the same time, it is preferable to have legacy compatibility.

  As a related technique, a wireless communication apparatus that simultaneously receives OFDM signals transmitted from a plurality of transmitters has been proposed (see, for example, Patent Document 1).

JP 2007-110456 A

  As described above, the wireless LAN is required to have legacy compatibility. For this reason, in a wireless communication system capable of transmitting data using a plurality of frequency bands simultaneously, data may be transmitted using a single frequency band. Therefore, in this case, the receiver needs to determine whether data is transmitted using a single frequency band or whether data is transmitted using a plurality of frequency bands simultaneously.

  This determination can be realized, for example, by notifying information indicating whether to use a single frequency band or a plurality of frequency bands at the same time between the transmitter and the receiver. However, in this case, there is a risk that the throughput may decrease due to overhead.

  An object according to one aspect of the present invention is to provide a method for determining whether or not data transmission using a plurality of frequency bands simultaneously is performed without reducing throughput.

  A wireless communication system according to one aspect of the present invention is a wireless communication system that transmits a frame from a first wireless communication apparatus to a second wireless communication apparatus using one or a plurality of frequency bands, The wireless communication device is provided for each frequency band, and each of a plurality of transmission circuits that transmit frames including a legacy signal field, A signal field setting unit configured to set the same value in a legacy signal field of a frame transmitted using a frequency band, wherein the second wireless communication device receives a legacy signal of a frame received via each frequency band The fields are compared with each other, and based on the comparison result, it is determined whether or not data transmission using the plurality of frequency bands simultaneously is performed. A judging unit for.

  According to the above-described aspect, it is possible to determine whether or not data transmission using a plurality of frequency bands at the same time is performed without reducing the throughput.

It is a figure which shows an example of the radio | wireless communications system concerning 1st Embodiment. It is a figure which shows an example of the transmitter with which the radio | wireless communication apparatus concerning 1st Embodiment is provided. It is a figure which shows an example of a structure of a preamble signal field. It is a figure which shows an example of a structure of a legacy signal field. It is a figure which shows an example of the receiver with which the radio | wireless communication apparatus concerning 1st Embodiment is provided. It is a flowchart which shows an example of the radio | wireless communication control method of 1st Embodiment. It is a figure which shows an example of the receiver with which the radio | wireless communication apparatus concerning 2nd Embodiment is provided. It is a flowchart which shows an example of the radio | wireless communication control method of 2nd Embodiment. It is a figure which shows an example of the receiver with which the radio | wireless communication apparatus concerning 3rd Embodiment is provided. It is a flowchart which shows an example of the radio | wireless communication control method of 3rd Embodiment.

<First Embodiment>
FIG. 1 shows an example of a wireless communication system according to the first embodiment. The wireless communication system 1 shown in FIG. 1 is not particularly limited, but is a wireless LAN system, for example. The wireless communication system 1 includes wireless communication devices 2 and 3. Each of the wireless communication devices 2 and 3 is, for example, a user terminal. The user terminal may be a mobile terminal.

  The wireless communication devices 2 and 3 can transmit data using a plurality of frequency bands. Specifically, the wireless communication devices 2 and 3 can transmit data using a plurality of frequency bands simultaneously. In this embodiment, the wireless communication devices 2 and 3 can transmit data using the 2.4 GHz band and the 5 GHz band. Note that the communication quality between the wireless communication apparatuses 2 and 3 differs for each frequency band. Therefore, the wireless communication apparatuses 2 and 3 may transmit data using different modulation schemes and different codes for each frequency band.

  FIG. 2 shows an example of the transmitter 10 included in the wireless communication devices 2 and 3. In this example, the transmitter 10 includes a distributor 21, a control unit 22, and a plurality of transmission circuits 23a and 23b as shown in FIG. A transmission circuit is provided for each frequency band. Further, the transmitter 10 may include other circuit elements not shown in FIG.

  When the distributor 21 transmits data using a plurality of frequency bands at the same time according to the distribution instruction given from the control unit 22, the transmission time in each frequency band is the same according to the transmission rate of each frequency band. The data is distributed to the plurality of transmission circuits 23a and 23b. The distributor 21 distributes data so that the transmission times in each frequency band are the same according to the SN ratio and communication quality of each frequency band.

  The control unit 22 includes a signal field setting unit 24. When the signal field setting unit 24 transmits data using a plurality of frequency bands at the same time according to an instruction given from an application, the legacy signal field (L-SIG :) of the frame transmitted using each frequency band is used. Set the same value for Legacy Signal Field. The configuration of the legacy signal field (L-SIG) will be described later.

  Each transmission circuit 23a, 23b is provided for each frequency band and transmits a frame including a legacy signal field. Each transmission circuit 23a and 23b includes frame generators 31a and 31b, encoders 32a and 32b, modulators 33a and 33b, and mixers 34a and 34b, respectively. Each transmission circuit 23a, 23b may include other circuit elements not shown in FIG.

  Each of the frame generators 31 a and 31 b generates a frame for transmitting input data from the data distributed by the distributor 21. An example of generating frames by the frame generators 31a and 31b will be described later.

  The encoders 32a and 32b encode the bit strings of the generated transmission frames, respectively. The modulators 33a and 33b each generate a modulated signal from the encoded bit string. Each mixer 34a, 34b multiplies the modulation signals output from the modulators 33a, 33b by the RF oscillation signals f1, f2. That is, the output signal (modulated signal) is up-converted to the radio frequency band. The frequencies of the RF oscillation signals f1 and f2 are 2.4 GHz band and 5 GHz band in the embodiment shown in FIG. Then, the transmission circuits 23a and 23b output signals via the antenna. Note that the modulation signals in each frequency band may be output via different antennas.

  Thus, each transmission circuit 23a, 23b can output a 2.4 GHz band signal and a 5 GHz band signal. And the radio signal (namely, 2.4GHz band signal, 5GHz band signal) output from each transmission circuit 23a, 23b is received by the radio | wireless communication apparatus located in the radio | wireless area of each transmission circuit 23a, 23b.

  The configuration of the preamble signal field set by the signal field setting unit 24 will be described with reference to FIGS. FIG. 3 shows an example of the configuration of the preamble signal field set by the signal field setting unit 24. FIG. 4 shows an example of the configuration of the legacy signal field in the preamble signal field.

  The signal field setting unit 24 generates a preamble signal field that is compatible with legacy systems such as IEEE802.11a / g / n / ac / ax. This preamble signal field is added to the head of each frame generated by the frame generators 31a and 31b.

  The preamble signal field set by the signal field setting unit 24 includes a legacy short training field (LSTF), a legacy long training field (LLTF), a legacy signal field (L-SIG), and a new signal field. Includes a signal field (NEW-SIG). LSTF and LLTF are each composed of a known repetitive signal.

  As shown in FIG. 4, the L-SIG includes a rate field (Rate) indicating a transmission rate, a length field (Length) indicating a data length, and a parity field (P) for parity bits.

  In a legacy system (for example, 802.11a / g), an actual communication parameter (that is, a value representing an actual transmission rate and a data length) is set in each field of L-SIG. On the other hand, in a recent system (hereinafter, “non-legacy system”), communication parameters are notified between wireless communication devices without using L-SIG. However, in order to ensure compatibility with legacy systems, frames transmitted in non-legacy systems also include L-SIG. For this reason, an actual communication parameter does not necessarily need to be set in the L-SIG of a frame transmitted in a non-legacy system.

  In the non-legacy system, a predetermined fixed rate (6 Mbps) is set in the rate field. In the length field, a value representing the data length transmitted at 6 Mbps is set based on the actual transmission time.

  The signal field setting unit 24 sets predetermined control information to NEW-SIG when transmitting data using a plurality of frequency bands simultaneously. NEW-SIG is a unique signal field in the present embodiment. In FIG. 3, two NEW-SIGs are provided in the frame, but each frame may be provided with an arbitrary number of NEW-SIGs. In the first embodiment, the NEW-SIG signal field may not be provided. Predetermined control information set in NEW-SIG will be described in a third embodiment to be described later.

  Here, an example of calculating the value set in the length by the signal field setting unit 24 will be described. In the present embodiment, a case where DATA is transmitted by N OFDM symbols is considered. N is an arbitrary natural number.

  First, the signal field setting unit 24 calculates the transmission time in one frequency band (for example, the first frequency band).

  LSTF length (8 μs) is T_LSTF, LLTF length (8 μs) is T_LLTF, L-SIG length (4 μs) is T_L-SIG, NEW-SIG length (4 μs) is T_NEW-SIG, DATA When the length (4 μs) is represented by T_DATA, the data transmission time can be represented by equation (1).

  Since the transmission time is distributed to the transmission circuits 23a and 23b by the distributor 21 so that the transmission time is the same in each frequency band, the transmission time is common regardless of each frequency band.

  Transmission time = T_LSTF + T_LLTF + T_L−SIG + T_NEW−SIG * 2 + T_DATA * N (Expression 1)

  Here, since the transmission rate is 6 Mbps, 24 bits (3 bytes) can be transmitted with one OFDM symbol. The length specified by Length is a length other than T_LSTF, T_LLTF, and T_L-SIG.

  Then, Length obtained by subtracting T_LSTF, T_LLTF, and T_L-SIG from the transmission time can be expressed by Equation (2).

Length = (transmission time− (T_LSTF + T_LLTF + T_L−SIG)) / 4 μs * 3 bytes
= (Transmission time -20) / 4 * 3 (Expression 2)

  In the IEEE802.11 WLAN standard, since the service field, tail, and pad bit are transmitted in addition to the data specified by the length accurately, the value obtained by subtracting 3 bytes is more preferably the actual length.

  Then, a more preferable Length obtained by subtracting 3 bytes from the above Equation 2 can be expressed by Equation (3).

  Length = ((transmission time−20) / 4) * 3-3 bytes (Expression 3)

  For example, when the transmission time is 100 μs, the data length is calculated as follows by substituting it into Equation 3.

  Length = ((100-20) / 4) * 3-3 = 57 bytes

  When the transmitter 10 transmits data using a plurality of frequency bands simultaneously, the signal field setting unit 24 sets the calculated Length in the L-SIG of a frame transmitted using each frequency band. That is, the same value is set in L-SIG of a frame transmitted using each frequency band. Then, the signal field setting unit 24 sends a preamble signal field including L-SIG set to the same value to the frame generators 31a and 31b.

  The frame generators 31a and 31b add a preamble signal field including L-SIG set by the signal field setting unit 24 to the head of each frame to be generated.

  Thus, when the transmitter 10 transmits data using a plurality of frequency bands (the first frequency band and the second frequency band) at the same time, the distributor 21 depends on the transmission rate of each frequency band. Thus, the input data is distributed to a plurality of transmission circuits so that the transmission times in each frequency band are the same. Here, the legacy signal field includes a rate field representing a transmission rate and a length field representing a data length. Then, the signal field setting unit 24 sets the same predetermined fixed rate (6 Mbps) in the rate field of the frame transmitted in the first frequency band and the rate field of the frame transmitted in the second frequency band, A value obtained by multiplying the transmission time by a fixed rate is set in the length field of the frame transmitted in the first frequency band and the length field of the frame transmitted in the second frequency band. Here, the “transmission time” is the same in the first frequency band and the second frequency band. Therefore, the values obtained by multiplying the transmission time by a fixed rate are also the same in the first frequency band and the second frequency band. As a result, when data is transmitted using the first frequency band and the second frequency band simultaneously, the same value is set in the legacy signal field of the frame transmitted using each frequency band. .

  When transmitting data using a plurality of frequency bands at the same time, the transmitter 10 preferably transmits frames in each frequency band in synchronization with each other. In particular, in a communication system in which data is transmitted by OFDM, it is required that frames in each frequency band be transmitted in synchronization with each other in order to suppress interference between subcarriers.

  FIG. 5 shows an example of a receiver included in the wireless communication apparatuses 2 and 3 according to the first embodiment. In this example, the receiver 11 includes a plurality of receiving circuits 40a and 40b and a control unit 45 as shown in FIG. The receiver 11 may include other circuit elements not shown in FIG.

  The reception circuits 40a and 40b include mixers 41a and 41b, timing detectors 42a and 42b, demodulators 43a and 43b, and decoders 44a and 44b, respectively. The receiving circuits 40a and 40b may include other circuit elements not shown in FIG. And the receiving circuits 40a and 40b receive the radio signal output from the transmitter 10 shown in FIG.

  As shown in FIG. 5, the mixers 41a and 41b are provided between the antenna and the timing detectors 42a and 42b. The mixers 41a and 41b multiply the radio waves (received waves) received via the antenna by the RF oscillation signals f1 and f2, respectively. The frequencies of these RF oscillation signals f1 and f2 are substantially the same as the frequencies of the RF oscillation signals f1 and f2 used in the transmission circuits 23a and 23b. Therefore, the received wave component of each frequency band f1, f2 is extracted.

  As a result, each received signal is down-converted to the baseband region. In the following description, the signals down-converted by the mixers 41a and 41b may be referred to as “S1” and “S2”, respectively.

  The timing detectors 42a and 42b detect the synchronization timing based on the output signals (for example, electric field information) of the received wave components extracted by the mixers 41a and 41b. For example, in a preamble signal field compatible with legacy systems such as IEEE802.11a / g / n / ac / ax, a LSTF, LLTF is used as a predetermined preamble at the head of each frame transmitted from each transmission circuit 23a, 23b. Is set. The preamble includes a known pattern. Then, the timing detectors 42a and 42b establish frame synchronization by monitoring the preamble in the received signal. Specifically, the timing detectors 42a and 42b establish frame synchronization by autocorrelation processing or cross-correlation processing using a preamble.

  The demodulators 43a and 43b demodulate the received signals S1 and S2 in the corresponding frequency bands in accordance with instructions given from the control unit 45, respectively. At this time, the demodulators 43a and 43b execute demodulation processing corresponding to the modulation processing by the modulators 33a and 33b.

  The decoders 44 a and 44 b decode the bit string output from the demodulators 43 a and 43 b according to the instruction given from the control unit 45. At this time, the decoders 44a and 44b execute a decoding process corresponding to the encoding by the encoders 32a and 32b.

  The control unit 45 controls the reception operation of the receiver 11, and the control unit 45 includes a determination unit 51 and an L-SIG check unit 52. Note that the controller 45 may include other circuit elements not shown in FIG.

  The determination unit 51 compares the L-SIG value of the frame of the reception signal S1 decoded by the decoders 44a and 44b with the L-SIG value of the frame of the reception signal S2. That is, the determination unit 51 includes L-SIG included in the received signal S1 (hereinafter referred to as “L-SIGa”) and L-SIG included in the received signal S2 (hereinafter referred to as “L-SIGb”). Compare the contents of the decryption results of. When the decoding results of L-SIGa and L-SIGb are the same, the determination unit 51 determines that the reception signal S1 and the reception signal S2 are transmitted in parallel by the transmitter 10. That is, it is determined that data transmission in which the first frequency band and the second frequency band are used simultaneously is being performed.

  The L-SIG check unit 52 checks whether or not the L-SIG of the frame received via each frequency band is correctly demodulated and decoded. If each L-SIG is correctly demodulated and decoded, it is estimated that the determination result by the determination unit 51 is correct. That is, the L-SIG check unit 52 is provided to improve the accuracy of determination by the determination unit 51.

  The L-SIG check unit 52 may extract the values of the parity fields (P) of L-SIGa and L-SIGb and determine whether or not a predetermined data area is damaged. When the predetermined data area is not damaged, the L-SIG check unit 52 determines that the reliability of the determination result of the determination unit 51 is high. On the other hand, when the predetermined data area is damaged, the L-SIG check unit 52 determines that the reliability of the determination result of the determination unit 51 is low.

  FIG. 6 is a flowchart illustrating an example of the wireless communication control method according to the first embodiment. In S11 and S12, the timing detectors 42a and 42b detect the synchronization timing based on the output signals S1 and S2 of the received wave components extracted by the mixers 41a and 41b. In S13 and S14, the demodulators 43a and 43b extract and demodulate L-SIGa included in the received signal S1 in the first frequency band and L-SIGb included in the received signal S2 in the second frequency band, respectively.

  In S15 and S16, the decoders 44a and 44b decode L-SIGa and L-SIGb included in the bit strings demodulated by the demodulators 43a and 43b, respectively. In S17, the determination unit 51 compares the result of decoding L-SIGa and the result of decoding L-SIGb.

  When the L-SIG decoding results are not the same (S18: No), the determination unit 51 determines that data transmission is being performed from the existing system. That is, the determination unit 51 determines that data transmission using a plurality of frequency bands simultaneously is not performed.

  When the decoding results of the L-SIG are the same (S18: Yes), the L-SIG check unit 52 determines whether or not the L-SIG of the frame received via each frequency band is correctly demodulated and decoded. Is checked (S19).

  When the L-SIG of each frequency band is not correctly demodulated and decoded (S19: NG), the L-SIG check unit 52 determines that the determination by the determination unit 51 is low in reliability. In this case, the control unit 45 determines that data transmission using a plurality of frequency bands simultaneously is not performed.

  When the L-SIG of each frequency band is correctly demodulated and decoded (S19: OK), the L-SIG check unit 52 determines that the determination by the determination unit 51 is highly reliable. In this case, the control unit 45 determines that data transmission using a plurality of frequency bands simultaneously has been performed.

  Thus, according to the first embodiment, when the transmitter performs data transmission using a plurality of frequency bands at the same time, the transmitter has the same value as the L-SIG of a frame transmitted using each frequency band. Set. At this time, in order to ensure compatibility with the legacy system, the same format as the L-SIG of the legacy system such as IEEE802.11a / g / n / ac / ax is used. Then, the receiver can determine whether or not data transmission using a plurality of frequency bands at the same time is performed depending on whether or not the L-SIGs received for each frequency band match each other. . In the first embodiment, the L-SIG decoding results of each frequency band are compared with each other.

  In the first embodiment, based on the L-SIG decoding result of each frequency band included in the legacy system format, it is determined whether data transmission using a plurality of frequency bands simultaneously has been performed. Therefore, it is possible to determine which frequency band is used with legacy compatibility and without extra overhead.

  The wireless communication devices 2 and 3 according to the first embodiment include a processor. The signal field setting unit 24, the determination unit 51, and the L-SIG check unit 52 are realized by executing a wireless communication control program using a processor. In this case, the wireless communication control program is stored in a memory area accessible by the processor. Distributor 21, frame generators 31a and 31b, encoders 32a and 32b, modulators 33a and 33b, mixers 34a, 34b, 41a and 41b, timing detectors 42a and 42b, demodulators 43a and 43b, decoder 44a and 44b may be realized by a hardware circuit.

<Second Embodiment>
In the first embodiment, the determination unit 51 compares the L-SIG decoding results included in each frequency band and determines whether or not the data transmission uses a plurality of frequency bands simultaneously. On the other hand, in 2nd Embodiment, it is determined whether it is the data transmission which uses a some frequency band simultaneously based on the correlation of the demodulation result of L-SIG contained in each frequency band.

  FIG. 7 shows an example of a receiver included in the wireless communication devices 2 and 3 according to the second embodiment. The receiver 12 according to the second embodiment includes a plurality of receiving circuits 40 a and 40 b and a control unit 70. The receiving circuits 40a and 40b are substantially the same in the first embodiment shown in FIG. 5 and the second embodiment shown in FIG. Further, the receiver 12 may include other circuit elements not shown in FIG.

  The control unit 70 includes a determination unit 71, an L-SIG synthesis unit 72, an L-SIG decoding unit 73, and an L-SIG check unit 74. The control unit 70 may include other circuit elements not shown in FIG.

  The determination unit 71 calculates a correlation between the L-SIGa demodulation result included in the reception signal S1 received via each frequency band and the L-SIGb demodulation result included in the reception signal S2. And when the correlation of the demodulation result of L-SIGa and L-SIGb is more than a predetermined threshold value, the determination unit 71 determines that the reception signal S1 and the reception signal S2 are transmitted in parallel by the transmitter 10. . That is, it is determined that data transmission in which the first frequency band and the second frequency band are used simultaneously is being performed.

  The L-SIG combining unit 72 combines the L-SIGa demodulation result included in the reception signal S1 and the L-SIGb demodulation result included in the reception signal S2 to generate a combined demodulation signal. The L-SIG decoding unit 73 decodes the bit string represented by the combined demodulated signal generated by the L-SIG combining unit 72. At this time, the L-SIG decoding unit 73 executes a decoding process corresponding to the encoding by the encoders 32a and 32b.

  The L-SIG check unit 74 checks whether or not the L-SIG of the frame received via each frequency band is correctly demodulated. If each L-SIG is correctly demodulated, it is estimated that the determination result by the determination unit 71 is correct. That is, the L-SIG check unit 74 is provided to improve the accuracy of determination by the determination unit 71.

  FIG. 8 is a flowchart illustrating an example of a wireless communication control method according to the second embodiment. In S21 and S22, the timing detectors 42a and 42b detect the synchronization timing based on the output signals S1 and S2 of the received wave components extracted by the mixers 41a and 41b.

  In S23 and S24, the demodulators 43a and 43b demodulate L-SIGa included in the received signal S1 in the first frequency band and L-SIGb included in the received signal S2 in the second frequency band, respectively.

  In S25, the determination unit 71 calculates the correlation between the result of demodulating L-SIGa and the result of demodulating L-SIGb. And when this correlation value is less than a predetermined threshold value (S26: No), the determination part 71 determines with data transmission being performed from the existing system. That is, the determination unit 71 determines that data transmission using a plurality of frequency bands simultaneously is not performed.

  On the other hand, when the correlation value is equal to or greater than the threshold (S26: Yes), the L-SIG combining unit 72 combines the L-SIG demodulated signals of the respective frequency bands to generate a combined demodulated signal ( S27).

  In S28, the L-SIG decoding unit 73 decodes the bit string represented by the combined demodulated signal generated by the L-SIG combining unit 72. In S29, the L-SIG check unit 74 checks whether or not the L-SIG is correctly demodulated in S23 and S24.

  When the L-SIG is not demodulated correctly (S29: NG), the L-SIG check unit 74 determines that the determination reliability by the determination unit 71 is low. In this case, the control unit 70 determines that data transmission using a plurality of frequency bands simultaneously is not performed. On the other hand, when L-SIG is correctly demodulated (S29: OK), the L-SIG check unit 74 determines that the determination by the determination unit 71 is highly reliable. In this case, the control unit 70 determines that data transmission using a plurality of frequency bands simultaneously is being performed.

  As described above, in the second embodiment, data transmission using a plurality of frequency bands at the same time is performed based on whether or not the correlation between the demodulation results of the respective frequency bands is high (for example, a predetermined threshold or more). It is determined whether or not. Therefore, it is possible to determine which frequency band has legacy compatibility and is used without extra overhead.

  The wireless communication devices 2 and 3 according to the second embodiment include a processor. The determination unit 71, the L-SIG synthesis unit 72, the L-SIG decoding unit 73, and the L-SIG check unit 74 are realized by executing a wireless communication control program using a processor. In this case, the wireless communication control program is stored in a memory area accessible by the processor.

<Third Embodiment>
In the first embodiment, the determination unit 51 compares the L-SIG decoding results included in each frequency band and determines whether or not the data transmission uses a plurality of frequency bands simultaneously. On the other hand, in the third embodiment, on the transmitter side, control information indicating which frequency band is being used simultaneously is set in the signal field. This control information is set, for example, in a NEW-SIG field newly prepared in the third embodiment. Although NEW-SIG is not specifically limited, For example, as shown in FIG. 3, it is set behind L-SIG. And in addition to the determination which uses L-SIG, a receiver determines whether the data transmission which uses a some frequency band simultaneously is performed based on the control information contained in NEW-SIG.

  The configuration of the transmitter included in the wireless communication devices 2 and 3 according to the third embodiment is substantially the same as the configuration of the transmitter according to the first embodiment shown in FIG. However, the signal field setting unit 24 of the third embodiment provides control information indicating which frequency band is being used simultaneously when the transmitter 10 transmits data using a plurality of frequency bands simultaneously. Set to NEW-SIG. For example, when the frequency bands used at the same time are 5 GHz and 2.4 GHz, the signal field setting unit 24 sets control information indicating that 5 GHz and 2.4 GHz are used simultaneously in NEW-SIG.

  FIG. 9 shows an example of a receiver included in the wireless communication apparatuses 2 and 3 according to the third embodiment. In this example, the receiver 13 includes a plurality of receiving circuits 40a and 40b and a control unit 90, as shown in FIG. The receiving circuits 40a and 40b are substantially the same in the first embodiment shown in FIG. 5 and the third embodiment shown in FIG. Further, the receiver 13 may include other circuit elements not shown in FIG.

  The control unit 90 includes a determination unit 91, an L-SIG check unit 92, NEW-SIG demodulation units 93 a and 93 b, NEW-SIG decoding units 94 a and 94 b, and a NEW-SIG determination unit 95. Note that the control unit 90 may include other circuit elements not shown in FIG. Since the determination unit 91 and the L-SIG check unit 92 of the third embodiment are substantially the same as the determination unit 51 and the L-SIG check unit 52 of the first embodiment, description thereof will be omitted.

  The NEW-SIG demodulation units 93a and 93b extract and demodulate NEW-SIGa and NEW-SIGb from the reception signal S1 in the first frequency band and the reception signal S2 in the second frequency band. The NEW-SIG decoding units 94a and 94b decode NEW-SIGa and NEW-SIGb from the output signals of the NEW-SIG demodulation units 93a and 93b.

  The NEW-SIG determination unit 95 acquires a control signal based on the decoding results obtained by the NEW-SIG decoding units 94a and 94b, and checks which frequency band is used at the same time. The NEW-SIG determination unit 95 determines whether data transmission is simultaneously performed in a plurality of frequency bands based on the check result.

  FIG. 10 is a flowchart illustrating an example of a wireless communication control method according to the third embodiment. About the process of S31-S38 of 3rd Embodiment, since it is substantially the same as the process of S11-S18 of 1st Embodiment, description is abbreviate | omitted.

  When the decoding results of L-SIG are not the same (S38: No), the determination unit 91 determines that data transmission is performed from the existing system. That is, the determination unit 91 determines that data transmission using a plurality of frequency bands simultaneously is not performed. In this case, the process of the control unit 90 proceeds to S40 and S41.

  If the L-SIG decoding results are the same (S38: Yes), the L-SIG check unit 92 checks whether or not the L-SIG is correctly demodulated and decoded (S39).

  When the L-SIG is correctly demodulated and decoded, the L-SIG check unit 92 determines that the determination by the determination unit 91 is highly reliable (S39: OK). That is, the control unit 90 determines that data transmission using a plurality of frequency bands simultaneously is being performed. On the other hand, when L-SIG is not demodulated or decoded correctly (S39: NG), the process of the control unit 90 proceeds to S40 and S41.

  In S40 and S41, the NEW-SIG demodulator 93a demodulates NEW-SIGa included in the received signal S1 in the first frequency band, and the NEW-SIG demodulator 93b generates the received signal S2 in the second frequency band. The NEW-SIGb included is demodulated. In S42 and S43, the NEW-SIG decoding units 94a and 94b respectively decode NEW-SIGa and NEW-SIGb included in the bit strings demodulated by the NEW-SIG demodulation units 93a and 93b. As a result, a control signal for each frequency band is obtained.

  In S44, the NEW-SIG determination unit 95 checks which frequency band is used at the same time based on the control signals obtained by the NEW-SIG decoding units 94a and 94b. When a control signal indicating that data transmission using a plurality of frequency bands simultaneously is performed from at least one frequency band (S45: Yes), the NEW-SIG determination unit 95 includes a plurality of NEW-SIG determination units 95. It is determined that data transmission using the same frequency band is performed at the same time.

  On the other hand, if a control signal indicating that data transmission using a plurality of frequency bands is performed simultaneously is not obtained from any frequency band (S45: No), a NEW-SIG determination unit 95. Determines that data transmission is being performed from the existing system. That is, the NEW-SIG determination unit 95 determines that data transmission using a plurality of frequency bands simultaneously is not performed.

  Thus, in the third embodiment, a plurality of frequency bands are simultaneously used based on the control information set in NEW-SIG in addition to the L-SIG decoding result of each frequency band included in the legacy system format. It is determined whether data transmission to be performed is performed. Therefore, in the third embodiment, whether the reception quality of any one of the plurality of frequency bands is poor and whether data transmission using the plurality of frequency bands at the same time is performed only by the contents of the L-SIG. Even if it cannot be determined, it is possible to accurately determine whether or not data transmission using a plurality of frequency bands simultaneously has been performed by using the NEW-SIG decoding result.

  The wireless communication devices 2 and 3 according to the third embodiment include a processor. The determination unit 91, the L-SIG check unit 92, the NEW-SIG demodulation units 93a and 93b, the NEW-SIG decoding units 94a and 94b, and the NEW-SIG determination unit 95 execute a wireless communication control program using a processor. Is realized. In this case, the wireless communication control program is stored in a memory area accessible by the processor.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, all the constituent elements shown in the embodiments may be appropriately combined. Furthermore, constituent elements over different embodiments may be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Wireless communication system 2, 3 Wireless communication apparatus 10 Transmitter 11, 12, 13 Receiver 21 Divider 22 Control part 23a, 23b Transmission circuit 24 Signal field setting part 31a, 31b Frame generator 32a, 32b Encoder 33a, 33b Modulators 34a, 34b Mixers 40a, 40b Reception circuits 41a, 41b Mixers 42a, 42b Timing detectors 43a, 43b Demodulators 44a, 44b Decoder 45 Control unit 51 Determination unit 52 L-SIG check unit 70 Control unit 71 Determination unit 72 L-SIG synthesis unit 73 L-SIG decoding unit 74 L-SIG check unit 90 control unit 91 determination unit 92 L-SIG check unit 93a, 93b NEW-SIG demodulation unit 94a, 94b NEW-SIG decoding unit 95 NEW-SIG Judgment part

Claims (7)

A wireless communication system that transmits a frame from a first wireless communication device to a second wireless communication device using one or more frequency bands,
The first wireless communication device is:
A plurality of transmission circuits provided for each frequency band, each transmitting a frame including a legacy signal field;
A signal field setting unit configured to set the same value in a legacy signal field of a frame transmitted using each frequency band when transmitting data using the plurality of frequency bands at the same time;
The second wireless communication device is:
A determination unit that compares legacy signal fields of frames received via each frequency band with each other and determines whether data transmission using the plurality of frequency bands is performed based on a result of the comparison. A wireless communication system comprising: The first wireless communication device further includes:
When transmitting data using the plurality of frequency bands at the same time, the data is transmitted to the plurality of transmission circuits so that the transmission time in each frequency band becomes the same according to the transmission rate of each frequency band. The wireless communication system according to claim 1, further comprising a distributor for distributing. The legacy signal field includes a rate field representing a transmission rate and a length field representing a data length,
When transmitting data using the first frequency band and the second frequency band at the same time, the signal field setting unit,
The same predetermined fixed rate is set in the rate field of the frame transmitted in the first frequency band and the rate field of the frame transmitted in the second frequency band,
A value obtained by multiplying the transmission time by the fixed rate is set in a length field of a frame transmitted in the first frequency band and a length field of a frame transmitted in the second frequency band. The wireless communication system according to claim 2. The determination unit, when the decoding result of the legacy signal field of the signal received through the first frequency band and the decoding result of the legacy signal field of the signal received through the second frequency band match each other, The wireless communication system according to any one of claims 1 to 3, wherein it is determined that data transmission using the first frequency band and the second frequency band simultaneously is performed. In the determination unit, the correlation between the demodulated signal in the legacy signal field of the signal received via the first frequency band and the demodulated signal in the legacy signal field of the signal received via the second frequency band is greater than a predetermined threshold. 4 is determined to be that data transmission using the first frequency band and the second frequency band at the same time is performed. Wireless communication system. The signal field setting unit simultaneously uses a plurality of frequency bands in a predetermined signal field of a frame transmitted using each frequency band when transmitting data using the plurality of frequency bands simultaneously. Set the control information that represents the data transmission,
When the determination unit does not determine that data transmission using a plurality of frequency bands at the same time is performed in the determination using the legacy signal field, the determination unit decodes the control information, and determines any one or more frequencies If the control information decoded from the band indicates that data transmission using a plurality of frequency bands is performed simultaneously, it is determined that data transmission using a plurality of frequency bands is performed at the same time. The radio | wireless communications system of any one of Claims 1-5. A wireless communication control method for transmitting a frame from a first wireless communication device to a second wireless communication device using one or a plurality of frequency bands,
The first wireless communication device is:
Provided for each frequency band, each transmitting a frame containing a legacy signal field,
When transmitting data using the plurality of frequency bands simultaneously, set the same value in the legacy signal field of the frame transmitted using each frequency band,
The second wireless communication device is:
The legacy signal fields of the frames received via each frequency band are compared with each other, and based on the comparison result, it is determined whether or not data transmission using the plurality of frequency bands is performed at the same time. A wireless communication control method.

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