JP6387541B2 - Wireless communication apparatus and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication apparatus and a wireless communication method.

  Wireless communication traffic is rapidly increasing due to the expansion of wireless LAN usage and the increase of devices with communication functions such as wireless surveillance cameras, etc., improving frequency utilization efficiency and accommodating more traffic on limited wireless resources. Is required.

  In a frequency band common to a plurality of systems such as an ISM (Industry-Science-Medical) band, each system determines a use frequency in an autonomous and distributed manner, so that a use frequency channel is biased.

  FIG. 14 is a diagram illustrating a usage state of the 2.4 GHz band measured on weekdays at Tokyo Station and Shinagawa Station.

  Since the horizontal axis represents frequency, it corresponds to the channel used, and the vertical axis represents time. In the figure, basically, the closer to white, the stronger the radio wave intensity received at the measurement point.

  FIG. 14 (a) shows the channel usage status at 10:00 on weekdays at Tokyo Station, and FIG. 14 (b) shows the channel usage status at 9am on weekdays at Shinagawa Station.

  In addition, the wireless LAN which is a typical system operated in the ISM band has an allocation of a plurality of bands such as the 5 GHz band in addition to the 2.4 GHz band. As with the frequency channel, the use band is biased.

  FIG. 15 is a diagram showing the received radio wave intensity of 2.4 GHz band and 5 GHz around Tokyo Station.

  FIG. 15A shows the channel usage situation of the 2.4 GHz band at 15:00 on weekdays at Tokyo Station, and FIG. 15B shows the channel usage situation of the 5 GHz band in the same time zone on the same day.

  As shown in FIG. 15, when a certain time zone is seen, there are unused radio resources. For example, in FIG. 15, it can be seen that congestion is seen in the 2.4 GHz band, but there is a vacancy in the 5.6 GHz band.

  On the other hand, a conventional wireless communication system, for example, LTE (Long Term Evolution) Release 8 (Rel-8), which is a wireless communication system standardized by 3GPP (3rd Generation Partnership Project), uses a maximum bandwidth of 20 MHz. And can communicate with each other.

  Furthermore, LTE-A (Long Term Evolution-Advanced), which is an advanced version of LTE, has a basic unit of bandwidth supported by LTE in order to achieve higher speed transmission while ensuring backward compatibility with LTE. Carrier aggregation (CA) technology that uses a plurality of component carriers (CC) bundled at the same time is adopted, and wideband transmission of 100 MHz width can be realized using 5 CC (100 MHz width) at the maximum. However, such carrier aggregation is transmission using different channels in adjacent frequency bands.

  Although speeding up as described above has been achieved, in recent years, the demand for mobile communication traffic has increased rapidly with the spread of highly functional portable terminals such as smartphones.

  As a result, in addition to the expansion of the use of the conventional wireless LAN (Local Area Network), the offload to the wireless LAN has progressed due to the increase in mobile data traffic due to the spread of smartphones, and the license-free bandwidth (2.4 GHz band, 5 GHz band) ) Is rapidly increasing.

  In addition, due to the progress of IoT (Internet Of Things) / M2M (Machine to Machine) society, there are concerns about further tightening of the above frequency band and 920 MHz band, and improving the frequency utilization efficiency of these frequency bands is an urgent issue Yes.

  Here, since the usage state of the radio resource varies depending on the time, place, frequency band, radio channel, and the like as described above, a situation in which only a part of the frequency band (or radio channel) is congested may occur.

  However, existing private wireless systems (for example, IEEE 802.11 wireless LAN) use a single frequency band or perform communication after determining one band to be used in advance. For example, IEEE 802.11n presets which of the 2.4 GHz band and the 5 GHz band is used. For this reason, there is a possibility that congestion may occur even when there is a vacant radio resource in the existing private wireless system as a whole.

  Here, cognitive radio technology is attracting attention in order to effectively use radio communication resources. The cognitive radio technology means that a wireless terminal recognizes the usage situation of surrounding radio waves and changes the radio communication resource to be used according to the situation. The cognitive radio technology includes a heterogeneous type in which different radio communication standards are selected and used according to a situation, and a frequency sharing type in which a radio terminal searches for a vacant frequency and secures a necessary communication band.

  In the heterogeneous type, the cognitive radio recognizes a plurality of radio systems operating in the vicinity, obtains information on the usage and feasible transmission quality of each system, and connects to an appropriate radio system. In other words, the heterogeneous cognitive radio indirectly increases the utilization efficiency of frequency resources by increasing the utilization efficiency of wireless systems existing in the vicinity.

  On the other hand, in the frequency sharing type, the cognitive radio has a frequency resource (this is called white space) that is not used temporarily or locally in a frequency band in which another radio system is operated. Is detected and signal transmission is performed using this. That is, the frequency sharing type cognitive radio directly increases the utilization efficiency of frequency resources in a certain frequency band.

  As a method for solving the problem of the increase in traffic in the license-free band as described above, a plurality of wireless LAN standards (for example, 2.4 GHz band wireless LAN standard and 5 GHz band wireless LAN standard) having different usage frequency bands are used. A heterogeneous cognitive radio approach that can be selected or used in parallel can be considered (for example, Patent Document 1 and Patent Document 2).

  However, in this heterogeneous cognitive radio approach, it is necessary to divide transmission data as appropriate and assign in advance which frequency band to transmit. As a result, depending on the degree of congestion of each frequency band, problems such as transmission delays greatly differing depending on the used frequency band and the order in which data arrives at the destination are newly generated.

  Therefore, it is desirable to realize cognitive wireless communication by sharing frequencies with existing systems in a plurality of frequency bands that are largely separated from each other, for example, 2.4 GHz band wireless LAN and 5 GHz band wireless LAN.

JP 2011-111433 A JP 2013-187561 A

  However, first, in order to determine which frequency band to use at the next transmission timing in the case where the communication is selectively performed in any of a plurality of frequency bands separated from each other as described above. Needs to perform sensing on multiple channels in the target band.

  Furthermore, carrier sensing is performed for a plurality of channels in the band, and communication is performed by simultaneously selecting a plurality of frequency channels that can be used at the time of transmission from the entire band.

  On the other hand, when simultaneous transmission / reception is performed in a plurality of frequency bands, it is necessary to immediately select and use a usable channel by sensing candidate target bands. In this case, it is necessary to simultaneously perform carrier sensing at the time of transmission for multiple channels that cover the entire target band, and it is necessary to further improve the efficiency of sensing.

  That is, since simultaneous transmission / reception of a plurality of frequency bands is performed, it is desirable to simultaneously sense the entire target band in order to find a free channel that can be used with the highest possible probability even during congestion. However, if multi-channel simultaneous sensing is performed with simple circuit parallelism, the circuit scale and power consumption increase, resulting in an increase in cost and a reduction in battery operable time. On the other hand, if the number of sensing target channels is reduced unplanned, the possibility that it is not possible to secure the number of frequency channels that can be transmitted necessary for communication during congestion will increase. In addition, there is a concern that in sensing with shortened observation time such as time-division sensing, the accuracy is lowered, and transmission is performed at the time of transmission by another station, so that errors increase. Therefore, it is necessary to increase the efficiency of sensing.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to select multiple channels when selectively communicating with a plurality of frequency bands used in mutually separated frequency bands. It is an object to provide a wireless communication apparatus and a wireless communication method capable of efficiently performing simultaneous sensing.

  Another object of the present invention is to provide a wireless communication apparatus and a wireless communication method capable of efficiently performing simultaneous multi-channel sensing when performing simultaneous parallel communication in a plurality of frequency bands separated from each other. is there.

According to one aspect of the present invention, random access control is performed in each of a plurality of frequency bands separated from each other, and a signal is transmitted using at least one of a plurality of radio channels in the plurality of frequency bands . A wireless communication device, a digital signal processing unit for generating a digital signal corresponding to a transmission packet, a plurality of high frequency signal processing units for converting a digital signal into a high frequency signal, and a plurality of frequency signals in a plurality of frequency bands A channel usage monitoring unit that performs channel sensing to monitor the usage status of radio channels, and sensing targets from multiple radio channels according to the channel sensing results of each group of multiple radio channels by the channel usage monitoring unit A channel was selected and carrier sense was executed for the selected radio channel Based on results, the access control unit for transmitting a signal from the high frequency processing unit, in response to the observed channel usage, based on the prediction by statistical analysis analysis, the possibility of common idle selected sensing target channel A channel usage state prediction unit that generates prediction information indicating a sensing period that is predicted to be high, and the access control unit performs carrier sense at the time of transmission in the sensing period based on the prediction information, and the idle state is In response to the detection, a signal is transmitted from the high-frequency processing unit.

  Preferably, the wireless communication device requests another wireless communication device to execute channel sensing, and the channel usage state observation unit uses its own channel sensing result and the channel sensing result from the other wireless communication device. Output as.

  Preferably, the wireless communication device shares a wireless channel for performing channel sensing with respect to a predetermined group of wireless channels with another wireless communication device, and the channel usage monitoring unit transmits its own channel sensing result and the other wireless communication. The channel sensing result from the device is output as usage status.

According to another aspect of the present invention, a wireless communication device for executing random access control in each of a plurality of frequency bands separated from each other and transmitting a signal using a plurality of radio channels in a plurality of frequency bands A transmission data is divided into a plurality of partial data corresponding to each of a plurality of frequency bands, a digital signal processing unit for generating a transmission packet for each frequency band, and provided for each frequency band, To generate a clock signal that is provided in common to a plurality of high-frequency signal processing units for converting a digital signal into a high-frequency signal for each corresponding frequency band, and used in the plurality of high-frequency processing units. Local oscillators and channels that perform channel sensing to observe channel usage in multiple frequency bands A sensing target channel is selected from a plurality of radio channels according to channel sensing results for each predetermined group of a plurality of radio channels by the usage status monitoring unit and the channel usage status monitoring unit, and a carrier is selected for the selected radio channel. Based on the result of the sense execution, each partial data from the high-frequency processing unit as a packet for each of a plurality of frequency bands, synchronously starting transmission at the same timing, and depending on the observed channel usage A channel usage state prediction unit that generates prediction information indicating a sensing period in which the selected sensing target channels are predicted to have a high possibility of being in an idle state in common based on prediction by statistical analysis analysis, and access control Based on the prediction information, the carrier sense at the time of transmission in the sensing period Run, in response to the idle state is detected, to transmit a signal from the high frequency processing unit.

  Preferably, the wireless communication device requests another wireless communication device to execute channel sensing, and the channel usage state observation unit uses its own channel sensing result and the channel sensing result from the other wireless communication device. Output as.

  Preferably, the wireless communication device shares a wireless channel for performing channel sensing with respect to a predetermined group of wireless channels with another wireless communication device, and the channel usage monitoring unit transmits its own channel sensing result and the other wireless communication. The channel sensing result from the device is output as usage status.

According to still another aspect of the present invention, a radio communication apparatus performing random access control in each of a plurality of frequency bands separated from each other transmits a signal using at least one of a plurality of radio channels. A method of generating a digital signal corresponding to a transmission packet, a step of converting the digital signal into a high-frequency signal, and a plurality of radios for each predetermined group of a plurality of radio channels in a plurality of frequency bands. Based on the step of performing channel sensing for observing channel usage and the prediction based on statistical analysis analysis according to the observed usage status, the selected sensing target channel is likely to be in an idle state in common. The step of generating prediction information indicating the predicted sensing period and the result of channel sensing In response, a sensing target channel is selected from a plurality of wireless channels , and carrier sense at the time of transmission is executed for the selected wireless channel based on the prediction information, and an idle state is detected. And a step of transmitting a high-frequency signal.

According to still another aspect of the present invention, a radio communication method for performing random access control in each of a plurality of frequency bands separated from each other, and transmitting a signal using a plurality of radio channels A step of dividing transmission data into a plurality of partial data corresponding to each of a plurality of frequency bands, generating a transmission packet for each frequency band, and a frequency corresponding to a digital signal for each frequency band A step of converting each band into a high-frequency signal, a step of generating a clock signal for processing to be converted into a high-frequency signal by a local oscillator commonly provided in a plurality of frequency bands, and a plurality of radio channels in a plurality of frequency bands performing a channel sensing to observe the usage of a plurality of radio channels for each predetermined group of observed Depending on usage, based on the prediction by statistical analysis analysis, and generating a prediction information indicating the sensing period the selected sensing target channel is predicted to be likely in the common idle channel sensing Depending on the result, a sensing target channel is selected from a plurality of radio channels , and carrier sense at the time of transmission is executed for the selected radio channel in the sensing period based on the prediction information, and an idle state is detected. Accordingly , a step of starting to transmit the high-frequency signal in synchronization with each partial data as a packet for each of a plurality of frequency bands at the same timing.

  According to the present invention, multi-channel simultaneous sensing can be performed efficiently.

  Further, according to the present invention, transmission data can be mapped to a plurality of frequency bands according to the sensing result, and data transmission can be performed by adjusting the transmission timing.

It is a figure which shows the concept of the channel sensing in communication with an own station and a partner station. It is a conceptual diagram for demonstrating the several radio channel in the frequency band isolate | separated mutually. It is a conceptual diagram for demonstrating the channel sensing performed in the structure shown in FIG. 3 is a functional block diagram for explaining a configuration of a transmitter 1000 according to the first embodiment. FIG. It is a conceptual diagram for demonstrating "area sharing sensing" which the transmitter 1000 of Embodiment 1 implements in cooperation with other transmitters. It is a conceptual diagram for demonstrating the structure of channel sharing sensing. It is a figure for demonstrating the concept which reduces the number of object channels of sensing by prediction sensing, when performing the carrier sense of the multi-channel of an object band. 4 is a conceptual diagram for explaining a configuration of a wireless communication system according to a second embodiment. FIG. It is a figure for demonstrating the specific example for mapping and transmitting transmission data to a several zone | band, and receiving and unifying collectively by the receiving side. FIG. 10 is a functional block diagram for explaining a configuration of a transmitting apparatus 1000 ′ according to the second embodiment. It is a functional block diagram for demonstrating the example of a more detailed structure of transmitter 1000 '. 6 is a functional block diagram for explaining a configuration of receiving apparatus 2000 according to Embodiment 2. FIG. 3 is a functional block diagram for explaining an example of a more detailed configuration of receiving apparatus 2000. FIG. It is a figure which shows the use condition of the 2.4-GHz band measured on weekdays at Tokyo station and Shinagawa station. It is a figure which shows the 2.4 GHz band and 5 GHz received radio wave intensity | strength around Tokyo station.

  Hereinafter, configurations of a wireless communication system and a wireless communication apparatus according to an embodiment of the present invention will be described. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.

  In the following, as an example for explaining the receiving apparatus of the present invention, a plurality of existing unlicensed bands (for example, 920 MHz band used for IoT etc., 2 used for wireless LAN, which are largely separated from each other as described above). (.4 GHz band and 5 GHz band) will be described with reference to an example of a transmission apparatus in a wireless communication system capable of performing cognitive wireless communication by sharing a frequency with an existing system.

In the following, “carrier sense” refers to sensing for detecting the presence or absence of a signal of a target radio channel and determining transmission timing by virtual carrier sense accompanied by power detection or decoding of a received signal. This means that “channel sensing” means sensing that performs communication monitoring or the like in order to grasp the usage status of the target channel in addition to sensing as carrier sense.
[Embodiment 1]
First, in the case of a configuration in which communication is performed selectively in at least one of a plurality of frequency bands separated from each other, in order to determine which frequency band to use at the next transmission timing, A configuration for performing simultaneous multi-channel channel sensing will be described.

  FIG. 1 is a diagram illustrating the concept of channel sensing in communication between a local station and a partner station.

  When the own station 10 intends to transmit to the partner station 20 from now on, it first performs channel sensing to confirm the use status of a plurality of channels in the used band.

  Here, when there are other communication devices 30.1 to 30.4 that use any of the channels in the usable band in the vicinity of the local station 10, these become interference sources and avoid the influence of the interference wave. Therefore, the local station 10 communicates with the counterpart station 20 by detecting and using a channel in an empty frequency band.

  FIG. 2 is a conceptual diagram for explaining a plurality of radio channels in frequency bands separated from each other.

  In FIG. 2, the 920 MHz band, the 2.4 GHz band, and the 5 GHz band described above are shown as an example of the license-unnecessary band with the horizontal axis as the frequency. Each frequency band includes a plurality of radio channels that are selectively used in communication.

  FIG. 3 is a conceptual diagram for explaining channel sensing performed in the configuration shown in FIG.

  As an example, in FIG. 3, first, in the reception period or the standby period, the local station 10 senses the radio channels in the plurality of radio bands for each predetermined group of radio channels. Here, such “channel sensing for each predetermined group of wireless channels” is called sensing 1, sensing 2, sensing 3,..., Sensing n. The “predetermined group of radio channels” may be obtained by dividing a plurality of radio channels into several groups for each frequency band, and grouping radio channels of a plurality of frequency bands into groups for each frequency band. You may call it. As described above, by performing group sensing on a plurality of wireless channels in a plurality of wireless bands and performing channel sensing, it is possible to suppress a load on a device required for channel sensing. Such “channel sensing for each predetermined group of radio channels” may be configured to be performed cyclically for a predetermined group.

  The channel sensing performed by the own station 10 during such a reception period or standby period is referred to as “background sensing”.

  Note that such channel sensing as background sensing may be performed by the wireless communication device of the own station 10 alone or in cooperation with the wireless communication device of another station, as will be described later. Good.

  Further, the local station 10 performs a search for a free radio channel in order to determine the transmission timing from the local station 10 in the transmission period based on the usage status of the wireless channel obtained by background sensing. This carrier sense is called real-time sensing.

  In real-time sensing, based on information obtained by background sensing, a radio channel to be subjected to sensing is selected and carrier sense is performed as follows.

    i) In background sensing, select a wireless channel whose rate of use (usage rate) during a predetermined period is less than a predetermined value as a sensing target (or target a wireless channel whose rate of use is higher than a predetermined level) Excluded).

    ii) As will be described later, carrier sense is executed in a period in which it is predicted that there is a high possibility of being in an idle state for each of a plurality of radio channels, based on prediction from the usage status in background sensing.

  FIG. 4 is a functional block diagram for explaining the configuration of transmitter 1000 of the first embodiment.

  Referring to FIG. 4, transmitting apparatus 1000 includes error correction encoding section 1110 for performing error correction encoding processing on transmission data, and interleaving for performing interleaving processing on data after error correction encoding. A radio frame (packet) for communicating with a predetermined wireless communication method such as mapping processing corresponding to communication in a selected frequency band or addition of a physical header is formed in accordance with an instruction from unit 1112 and access control unit 1080 In response to an instruction from the access control unit 1080, the radio frame generation unit 1016 for executing the digital processing and the digital signal from the radio frame generation unit 1016 to the subsequent processing for the selected frequency band Band selection units 1018.1 to 1018.3 for selectively providing data, and corresponding frequencies A high-frequency processing unit (RF unit) that performs digital-analog conversion processing, modulation processing to a predetermined modulation method (for example, orthogonal modulation processing for a predetermined multi-level modulation method), up-conversion processing, power amplification processing, etc. ) 1040.1 to 1040.3 and antennas 1050.1 to 1050.3 for transmitting high-frequency signals of the RF units 1040.1 to 1040.3, respectively.

  Furthermore, the transmission apparatus 1000 includes a channel usage status monitoring unit 1060 that monitors usage statuses (such as availability of each radio channel) of each frequency band (one or more radio channels in each frequency band), and a channel usage status. Based on the observation result (usage status information) of the observation unit 1060, a channel usage status prediction unit 1070 that predicts the channel usage status at a predetermined timing, a radio frame generation unit 1016, and band selection units 1018.1 to 1018.3 , By controlling the RF units 1040.1 to 1040.3 and the channel utilization state observation unit 1060, the frequency band / wireless channel that has been found to be unused in real-time sensing is selected for a predetermined period at the controlled transmission timing And an access control unit 1080 that controls to transmit a wireless packet. Here, the channel usage state observation unit 1060 is configured to perform the above-described carrier sensing and channel sensing.

Note that, as will be described later, it is not essential in the present embodiment to predict the channel usage status, but simply a radio channel that is subject to real-time sensing based on the usage status in background sensing, for example, the usage rate. The structure which selects may be sufficient.
(Regional sharing sensing)
FIG. 5 is a conceptual diagram for explaining “area sharing sensing” performed by the transmitter 1000 according to the first embodiment in cooperation with other transmitters.

  Such “region sharing sensing” will be described as being executed in the background sensing described with reference to FIG. 3.

  At the time of background sensing explained in FIG. 3, the own station 10 cannot receive signals from the interference sources 30.1 to 30.3 due to obstacles and the like, and the other station 20 has a weak received signal and is demodulated. If it is not possible, the signals of the interference sources cannot be separated and identified, and it may be difficult to determine the communication start time and duration.

  Therefore, the local station 10 can request the sensing to the other station 40 in the vicinity, so that the local station 10 and the other station 40 share the channel sensing at a certain time. The other station 40 may be a terminal as well as a base station.

  In this case, the channel usage state monitoring unit 1060 receives not only the channel sensing result of itself but also the channel sensing result from another wireless communication device that has requested channel sensing via a receiving unit (not shown). Then, information from itself and other wireless communication devices is given to the channel usage status prediction unit 1070 as usage status information.

Through shared sensing, not only the results of channel sensing of the own station, but also the transmission cycle and transmission duration of each interference source or the statistical processing results are provided from other stations to determine the usage rate of the radio channel. As described later, it is possible to predict the duration of the idle state and the duration of the busy state. As a result, sensing information notified from a station (terminal) that exists in a region where the reception state of the interference wave can be detected more easily can be used, so the accuracy of determining the usage rate of the radio channel and the carrier at the time of transmission can be used. It is possible to improve the prediction accuracy during a period when there is a high possibility of vacancy to be sensed.
(Channel sharing sensing)
Furthermore, in order to reduce the number of sensing channels in background sensing, it is also possible to adopt a configuration in which wireless channels that are sensed between nearby terminals are shared.

  FIG. 6 is a conceptual diagram for explaining the configuration of channel sharing sensing.

  In order to reduce the number of sensing channels, wireless channel sensing is shared between nearby stations or terminals. In FIG. 6, the frequency channel in each frequency band is shared by the own station 10, the sharing station 40.1, and the sharing station 40.2. Here, for example, in each frequency band, the own station 10 shares channel 1 (CH1), the sharing station 40.1 shares channel 2 (CH2), and the sharing station 40.2 shares channel 3 (CH3). Yes. In each frequency band, the number of radio channels handled by the own station and each branch station may be one as described above, or may be two or more.

  However, as a method of allocating channels to be shared, for example, the own station 10 has a plurality of channels in the 2.4 GHz band, and the sharing station 40.1 has a plurality of channels in the low band of 5 GHz. .2 may share a plurality of radio channels for each predetermined frequency band, such that .2 shares a plurality of channels in the 5 GHz band high range.

  In these cases, the channel usage state observation unit 1060 receives not only its own channel sensing result but also a channel sensing result from another wireless communication apparatus that has shared the channel sensing via a receiving unit (not shown). Then, information from itself and other wireless communication devices is given to the channel usage status prediction unit 1070 as usage status information.

  With regard to such sharing, the sharing distribution method and the number of stations (terminals) to be shared are determined in advance, and which station (terminal) shares each sharing channel determined by the distribution method is predetermined. The timing can be determined by negotiation between neighboring stations (terminals). The own station and each sharing station share the result of channel sensing by communicating with each other.

  In addition, since it is difficult to sense the transmission frequency channel and its nearby frequencies during transmission of the local station, the sharing station that is less susceptible to transmission senses the same frequency channel by sensing the frequency channel in this band. There is also a method of supplementing information by sharing timing.

  In this way, it is possible to reduce the number of channels to be sensed per station (terminal).

It is also possible to implement “area sharing sensing” and “channel sharing sensing” in combination.
(Predictive sensing: Reducing the number of sensing channels by predicting idle periods)
Below, based on the usage status information obtained during background sensing, a configuration is described in which the channel usage status prediction unit 1070 selects a radio channel for performing carrier sensing in real time and predicts and sets a sensing period. First, as a premise for explaining the operations of the channel usage status observation unit 1060 and the channel usage status prediction unit 1070, a general method for avoiding a transmission collision from each terminal in a wireless LAN will be briefly described for explanation of terms. Explained.

  In wireless LAN, if terminals do not wait for transmission, packets collide and efficient communication cannot be established. Therefore, multiple terminals share the same line by transmitting after confirming that there is no other transmission signal. A method called “CSMA (Carrier Sense Multiple Access)” is adopted. At the time of transmission, there should be a waiting time with randomness called “Distributed access Inter Frame Space (DIFS)” and “Contention Window (CW)”, and no other transmission signal after that. Confirm before sending. Such a method is called “CA (Collision Avoidance)”.

  Further, after transmission, it always waits for “ACK (ACKnowledgement, arrival confirmation response)”. If ACK does not return, it is determined that a collision has occurred, and retransmission is performed. This is because, in the case of radio, it is difficult to reliably detect a collision during transmission.

  In addition to this, there is “RTS / CTS (Request to Send / Clear to Send)” devised for countermeasures against hidden terminals, for example, as a wireless LAN-specific access control mechanism. Here, the hidden terminal is a terminal that is out of the radio range from itself but is in the radio range of the communication partner. Although it cannot be known directly, it causes interference.

  Assuming that the reach of radio waves is Lm, consider a situation in which the communication partner B (access point) of the wireless terminal A is Lm ahead, and another wireless terminal C is further Lm ahead.

  At this time, since the radio wave of the terminal C does not reach the terminal A, the terminal C does not know the existence of the terminal C even if the terminal A checks whether another terminal is transmitting a signal (even if carrier sense is performed). It becomes a hidden terminal of terminal A. If no measures are taken, even if terminal C is transmitting to access point B, terminal A will also transmit data to access point B. This causes a collision at the access point B and causes a reduction in throughput.

  RTS / CTS is a mechanism in which a wireless device transmits a “RTS (transmission request)” packet before transmission, and responds with “CTS (receivable)” when the receiving side receives RTS. In the above example, terminal C first transmits RTS to access point B. However, it is assumed that this RTS does not reach the terminal A.

  Thereafter, the access point B notifies the terminal C that it can be received by transmitting a CTS. Since this CTS also reaches the terminal A, the terminal A senses that communication is performed in the vicinity, and postpones transmission. In the RTS / CTS packet, the scheduled occupation period of the channel is written. During this period, the terminal that has received this holds the communication. This period is called “NAV (Network Allocation Vector)”.

  The usage statistics for each radio channel calculated and predicted by the channel usage status prediction unit 1070 from the observation and measurement results for a predetermined period given from the channel usage status monitoring unit 1060 to the channel usage status prediction unit 1070 are as follows: There is something like this.

a) Probability of becoming busy (time utilization rate)
b) Probability distribution of duration between busy and idle states c) Duration of idle / busy state duration relative to previous busy / idle state duration Occurrence probability distribution (for example, probability density function (PDF) or cumulative distribution function (CDF))
d) Occurrence pattern of busy and idle states (period and duty ratio: when background traffic is periodic)
Below, the specific example of the prediction information which the channel utilization condition prediction part 1070 calculates among the above is demonstrated.

1) Method of calculating “idle state duration occurrence probability distribution” The probability density function (PDF) p (τ) of the frame arrival interval τ of the wireless LAN is a Pareto represented by the following equation (1): It is known that it generally follows the (Pareto) distribution (see Document 1 below).

  Reference 1: Dashdorj Yamkhin and Youjip Won, “Modeling and analysis of wireless LAN traffic,” Journal of Information Science and Engineering, vol. 25, no. 6, pp. 1783-1801, Nov. 2009.

Here, a is a coefficient for determining the distribution shape, and τ _m is the minimum frame arrival interval.

When a and τ _m are given, the mean μ and the variance σ ² of τ are given by the following equations (2) and (3) when a> 2.

For example, in the case of the IEEE 802.11 DCF standard, the minimum arrival interval of data frames is equal to or greater than the above-described DIFS + CW. Therefore, when the minimum value of CW is CWmin, τ _m = DIFS + CWmin is set. If the duration of the idle state is the frame arrival interval and μ and σ ² are measured from the channel sensing result, the channel usage state prediction unit 1070 can estimate the value of a using the above formula.

  If the value of a is obtained, the channel usage state prediction unit 1070 obtains an occurrence probability distribution represented by the following equation as a probability C (τ) that the idle state continues for τ time or longer.

When a radio channel scheduled to be used is in an idle state, the probability that the idle state continues from that point until t can be obtained from C (τ).

  2) As a result of sensing, if the idle duration and busy duration are approximately the same each time, and the channel usage state prediction unit 1070 determines that the traffic is periodic, the idle ( As an occurrence probability distribution of the duration of the idle state, for example, idle (idle) from the start of the idle state to the average value of the idle state duration (which may be a median or minimum value) ) It may be a step function in which the continuation probability is 100% and thereafter is 0%.

  3) On the other hand, when the wireless channel to be used is busy (for example, the current state of the 5 GHz band in FIG. 7 described later), the frame described in the physical header of the incoming packet (frame) By decoding the length and the value of the NAV described in the MAC frame, the channel usage state prediction unit 1070 can acquire the busy state duration and predict the busy state duration.

  FIG. 7 is a diagram for explaining the concept of reducing the number of sensing target channels by predictive sensing when performing multi-channel carrier sensing in the target band.

  In FIG. 7, as an example, a case where the 2.4 GHz band and the 5 GHz band are simultaneously sensed will be described. However, more frequency bands may be sensed simultaneously.

  As shown in FIG. 7, in the present embodiment, for example, sensing is not necessarily performed on all channels at the same time, and carrier sensing is performed by selecting a sensing period.

  At this time, the period of each transmission is predicted by statistical analysis as described above, and the carrier sense at the time of transmission is transmitted only during a period in which the possibility of a free state (idle state) is predicted to be high. set to target. The number of carrier sense target channels may be the same as the number of channels required for transmission, or may be increased depending on the prediction accuracy.

As described above, by predicting the duration of the idle state and the duration of the busy state, the carrier sense can be configured in a period in which the probability of being in the idle state is expected to be high. Sensing for transmission / reception in a plurality of frequency bands can be efficiently performed by setting the channel as a target of carrier sense at the time of transmission only during a period when the possibility of vacancy is high according to the prediction result.
[Embodiment 2]
The channel sensing technology as described in the first embodiment senses a plurality of channels in a plurality of bands, and simultaneously selects and transmits a plurality of frequency channels that can be used at the time of transmission from the entire band to perform simultaneous transmission / reception of a plurality of frequency bands. It can also be used when performing.

  Here, the radio communication apparatus according to the second embodiment is generally applied to a reception apparatus that performs communication in parallel at the timing synchronized with the same radio system using a plurality of frequency bands separated from each other. It is possible. In addition, as will be described later, the wireless communication device of the present invention may be applied to a receiving device that performs communication in parallel at a timing synchronized by different wireless systems using a plurality of frequency bands separated from each other. Is possible.

  FIG. 8 is a conceptual diagram for explaining the configuration of the wireless communication system according to the second embodiment.

  Referring to FIG. 8, on the premise that three frequency bands of 920 MHz band, 2.4 GHz band, and 5 GHz band are used on the transmission side, a transmission frame is assumed to use one radio channel in each band. Configure.

  In addition, although it is good also as using several channels in each frequency band, below, it demonstrates as what uses one channel for every frequency band.

  In the second embodiment, radio access control having the following characteristics is performed.

  That is, first, the transmitting side senses and observes the usage status (such as availability of each radio channel) of a plurality of frequency bands by a method described later.

  Subsequently, the transmitting side transmits wireless packets (frames) at the same time using one or more unused frequency bands / radio channels. At this time, transmission data is mapped to a plurality of bands and transmitted.

  On the other hand, the receiving side collectively receives data from a plurality of bands and integrates the data.

  In such a transmission / reception, such a configuration can ensure a transmission opportunity even if there is a bias in the congestion situation between bands, so that it can be expected to improve frequency utilization efficiency and reduce transmission delay, and the data arrival order may be switched. There is no problem.

  FIG. 9 is a diagram for explaining a specific example for mapping transmission data to a plurality of bands and transmitting the data, and collectively receiving and integrating the data on the receiving side.

  As shown in FIG. 9, transmission data is divided by the number of symbols proportional to the transmission rate Ri of each band using the transmission sequence, and assigned to each band by serial / parallel conversion.

  For example, if (5 GHz band transmission rate: 2.4 GHz band transmission rate: 920 MHz band transmission rate) = (R1: R2: R3) = (3: 2: 1), the transmission data series is divided every 6 symbols, Three symbols, two symbols, and one symbol are allocated to the 5 GHz band (ch1), 2.4 GHz band (ch2), and 920 MHz band (ch3). Note that dividing and allocating a transmission sequence is not limited to such a case, and more generally, when m frequency bands are used, the ratio of frequency band transmission rates is set to (R1: R2). : ...: Rm) (assuming that the ratio is expressed as irreducible), the transmission sequence is divided into (R1 + R2 + ... + Rm) × n (m, n: natural number) symbols. R1 × n) symbols, (R2 × n) symbols,..., (Rm × n) symbols may be assigned.

  After such assignment, for each band, a physical header is attached to the transmission symbol to form a packet, and these packets are transmitted simultaneously and in parallel at the same timing.

  The number of symbols assigned to each band on the transmission side is stored as information in this physical header, or preset as control information before transmission.

On the receiving side, synchronization and demodulation processing are performed using a physical header on each band. The demodulated sequences are combined by parallel / serial conversion in the reverse process of the transmission side, and the frame is decoded.
[Configuration of transmitter]
FIG. 10 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 ′ according to the second embodiment.

  Referring to FIG. 10, transmitting apparatus 1000 ′ includes error correction encoding section 1110 for performing error correction encoding processing on transmission sequence data, and interleaving processing for data after error correction encoding Interleaving unit 1112 for performing the processing, serial / parallel conversion (hereinafter referred to as S / P conversion) unit 1010 for performing processing to be assigned to each frequency band as described in FIG. 6, and data after S / P conversion , Radio frame generation units 1020.1 to 1020 for executing digital processing for forming a radio frame (packet) for communication by a predetermined radio communication method such as mapping processing and addition of a physical header for each frequency band. 3 and the digital signals from the radio frame generation units 1020.1 to 1020.3, respectively, digital-analog conversion processing, predetermined High-frequency processing units (RF units) 1040.1 to 1040.3 that perform modulation processing (for example, orthogonal modulation processing for a predetermined multi-level modulation method), up-conversion processing, power amplification processing, and the like; And antennas 1050.1 to 1050.3 for transmitting high-frequency signals of RF sections 1040.1 to 1040.3, respectively. The operations of the RF units 1040.1 to 1040.3 are controlled based on a clock from a local oscillator 1030 provided in common to these units.

  Furthermore, the transmission apparatus 1000 includes a channel usage status monitoring unit 1060 that monitors usage statuses (such as availability of each radio channel) of each frequency band (one or more radio channels in each frequency band), and a channel usage status. Based on the observation of the observation unit 1060, the channel usage status prediction unit 1070 that predicts the channel usage status at a predetermined timing, the processing timing of the radio frame generation units 1020.1 to 1020.3, and the transmission timing of the RF unit And an access control unit 1080 that controls to simultaneously transmit wireless packets in unused frequency bands and wireless channels for a predetermined period at the same controlled transmission timing.

  Also here, the channel usage state monitoring unit 1060 is configured to perform the above-described carrier sensing and channel sensing.

  Here, the access control unit 1080 selects and uses a channel that has been found to be usable according to the result of carrier sensing a target band that is a candidate at the time of transmission, and is unused at the same controlled transmission timing. Wireless packets are transmitted simultaneously on the frequency band and wireless channel.

  As described with reference to FIG. 6, the transmission apparatus 1000 configured as described above maps and transmits data to a plurality of bands, and the receiving side collectively receives the plurality of bands and integrates the data.

  FIG. 11 is a functional block diagram for explaining an example of a more detailed configuration of the transmission apparatus 1000 ′.

  The functional block diagram shown in FIG. 11 shows, as an example, the configuration of a transmission device that conforms to a wireless communication scheme similar to the wireless communication standard 802.11a.

  That is, although the wireless communication standard 802.11a is a wireless LAN communication system of 5 GHz band, in FIG. 11, only the frequency band is different even in the 2.4 GHz and 920 MHz bands. It shall be assumed that a receiver conforming to

  Therefore, in each frequency band, the configuration of the preamble portion of the packet is common to a plurality of frequency bands.

  However, it is not always necessary that the wireless communication system of each frequency band has the same configuration, even if the wireless communication system (signal format, symbol length, subcarrier interval, etc.) differs for each frequency band. Good. In this case, at least a single transmission sequence is divided into each band and transmitted at the same time, and the configuration of the RF section is basically the same except that the frequency bands are different, and the configuration of the preamble portion of the packet (Preamble length, etc.) may be different for each of a plurality of frequency bands.

  FIG. 11 exemplarily shows a configuration related to transmission in the 5 GHz band. Since a wireless communication system similar to the wireless communication standard 802.11a is assumed, a signal to be transmitted is subjected to OFDM (Orthogonal Frequency Division Multiplexing) modulation.

  Referring to FIG. 11, radio frame generation section 1020.3 receives transmission data distributed from S / P conversion section 1010, and executes mapping section 1122 for executing mapping processing and inverse Fourier transform processing. An IFFT unit 1130 for adding a guard interval, a GI adding unit 1140 for adding a guard interval portion, and a digital-analog converter (DAC) 1150 for converting a digital signal into an analog signal of an I component and a Q component.

  The high frequency processing unit 1040.3 includes a quadrature modulator 1210 for modulating a signal from the DAC 1150 into a predetermined multilevel modulation signal, an upconverter 1220 for upconverting the output of the quadrature modulator 1210, and an output of the upconverter 1220. And a power amplifier 1230 for amplifying and transmitting the signal from the antenna 1050.3.

  As a result, the baseband OFDM signal is converted into a carrier band OFDM signal by the RF unit 1040.3.

  Further, the high frequency processing unit 1040.3 is based on a clock frequency conversion unit 1310 for converting a reference frequency signal from the local oscillator 1030 into a reference clock signal in a corresponding frequency band, and a reference clock from the clock frequency conversion unit 1310. Based on the reference clock from the clock frequency conversion unit 1310 and the clock generation unit 1320 that generates the clock used for the modulation processing in the quadrature demodulator 1210, the clock used for the up-conversion processing in the up-converter 1220 is generated. Clock generation unit 1340.

  That is, the reference frequency signal from the local oscillator 1030 is used as a clock signal in the conversion from the baseband OFDM signal to the carrier band OFDM signal. More generally, even when the wireless communication systems are different, the reference frequency signal from the local oscillator 1030 is basically used as a clock signal in the conversion from the baseband signal to the carrier band signal.

  Note that the configurations and operations of the channel usage status observation unit 1060 and the channel usage status prediction unit 1070 can be the same as those described in the first embodiment.

  That is, the channel usage state observation unit 1060 performs at least one of “region sharing sensing” and “channel sharing sensing” and real-time sensing processing in background sensing according to the operation state. Further, the channel usage state prediction unit 1070 performs the processing described in “Predictive sensing”.

  At this time, because of the simultaneous transmission of multiple frequencies, the number of channels required for transmission is subject to carrier sense during transmission only during the period when it is predicted that there is a high possibility that the number of channels will be idle (idle state) And

  In this case, when “predictive sensing” is performed, the channel is sensed only during a period in which it is predicted that there is a high possibility of an idle state (idle state). Since sensing can be performed efficiently, the possibility of acquiring the number of channels necessary for transmission increases. Further, when it is considered that the possibility that the necessary number of transmission channels can be acquired is extremely low, it is possible to reduce the carrier sense load by not performing sensing. When the predicted period overlaps in multiple frequency bands and it is determined that multiple channels are idle at the same time based on the result of carrier sense at that time, multiple channels are used to Simultaneous bandwidth transmission.

That is, the channel usage status monitoring unit 1060 observes the usage status of each frequency band (for example, the availability of each radio channel and the busy probability) based on the sensing result of the local station and / or the sensing result of the sharing station, and the channel usage. The situation predicting unit 1070 predicts the most recent usage situation of each frequency band, and accordingly, by setting the channel as a target of carrier sense at the time of transmission only in a period when the possibility of vacancy is high according to the prediction result, Channel sensing for simultaneous transmission and reception of frequency bands can be performed efficiently.
[Receiver configuration]
Below, the structure of the receiver used in the radio | wireless communications system which was demonstrated in FIG. 8 is demonstrated.

  FIG. 12 is a functional block diagram for explaining a configuration of receiving apparatus 2000 of the second embodiment.

  Referring to FIG. 12, receiving apparatus 2000 includes antennas 201. 1 to 201 0.3 and antennas 201. 1 for receiving signals in a plurality of frequency bands (920 MHz band, 2.4 GHz band, and 5 GHz band), respectively. Common to the receiving units 2100.1 to 2100.3 and the receiving units 2100.1 to 2100.3 for executing reception processing such as down-conversion processing, demodulation / decoding processing, etc. A local oscillator 2020 that generates a reference frequency signal that is a clock serving as a reference for the operation of the receiving units 2100.1 to 2100.3, and each sequence of signals from the receiving units 2100.1 to 2100.3 as a transmitting side. In the reverse process, a parallel / serial conversion unit 2700 for coupling by parallel / serial conversion is included.

  The output of the integrated frame from the parallel / serial (P / S) conversion unit 2700 is passed to the upper layer.

  The receiving device 2000 detects the frequency offset of the local oscillator 2020 from the received preamble signal, generates a signal (oscillation frequency control signal) for controlling the oscillation frequency of the local oscillator 2020, and performs carrier frequency synchronization processing. And a synchronization processing unit 2600 that generates a signal (synchronization timing signal) for timing synchronization in digital signal processing from the received signal.

  Receiving section 2100.1 receives the signal from antenna 2010.1, and performs low-noise amplification processing, down-conversion processing, demodulation processing for a predetermined modulation scheme (for example, orthogonal demodulation processing for a predetermined multilevel modulation scheme), analog A high-frequency processing unit (RF unit) 2400.1 for executing digital conversion processing and the like, and a baseband for executing baseband processing such as demodulation / decoding processing on the digital signal from the RF unit 2400.1 A processing unit 2500.1 is included.

  The receiving unit 2100.2 also includes a high frequency processing unit (RF unit) 2400.2 and a baseband processing unit 2500.2 for performing similar processing for the corresponding frequency band. The receiving unit 2100.3 also includes a high frequency processing unit (RF unit) 2400.3 and a baseband processing unit 2500.3 for performing similar processing for the corresponding frequency band.

  The baseband processing units 2500.1 to 2500.3 and the parallel / serial (P / S) conversion unit 2700 are collectively referred to as a digital signal processing unit 2800.

  FIG. 13 is a functional block diagram for explaining an example of a more detailed configuration of receiving apparatus 2000 shown in FIG.

  The functional block diagram shown in FIG. 13 also shows the configuration of a receiving device according to the same wireless communication scheme as the wireless communication standard 802.11a as an example.

  Therefore, the configuration of the receiving device corresponds to the configuration of the transmitting device shown in FIG.

  FIG. 13 also exemplarily shows the configuration of the reception unit 2100.3 in the 5 GHz band.

  Referring to FIG. 13, RF section 2400.3 of receiving section 2100.3 performs low-frequency amplifier 3010 for amplifying the received signal from antenna 2010.3 and frequency conversion of the output of low-noise amplifier 3010. Down converter 3020, automatic gain controller 3030 for controlling the output of down converter 3020 to have a predetermined amplitude, quadrature demodulator 3040 for demodulating a predetermined multilevel modulation signal, and quadrature demodulator And an analog-digital converter (ADC) 3050 for converting the I component output and the Q component output of 3040 into digital signals.

  The RF unit 2400.3 is further based on a clock frequency conversion unit 3060 for converting the reference frequency signal from the local oscillator 2020 into a reference clock signal in a corresponding frequency band, and a reference clock from the clock frequency conversion unit 3060. Based on the reference clock from the clock frequency conversion unit 3060 and the clock generation unit 3070 for generating the clock used for the down-conversion processing in the down converter 3020, the clock used for the demodulation processing in the quadrature demodulator 3040 is generated. A clock generation unit 3080.

  Since a wireless communication system similar to the wireless communication standard 802.11a is assumed, the transmitted signal is subjected to OFDM (Orthogonal Frequency Division Multiplexing) modulation. As a result, the RF band 2400.3 converts the carrier band OFDM signal into a baseband OFDM signal.

  The reference frequency signal from the local oscillator 2020 is used for carrier frequency synchronization in the conversion from the carrier band OFDM signal to the baseband OFDM signal. More generally, even when the wireless communication systems are different, the reference frequency signal from the local oscillator 2020 is basically used for carrier frequency synchronization in conversion from a carrier band signal to a baseband signal.

  Referring back to FIG. 13 again, the baseband processing unit 2500.3 receives the signal from the ADC 3050, and with respect to the GI removal unit 4010 for removing the guard interval part and the signal from which the guard interval has been removed, An FFT unit 4020 for executing the fast Fourier transform and a demapping unit 4032 for executing a demapping process on the output of the FFT unit 4020 are included.

  After performing guard interval removal, FFT processing and demapping processing in the baseband processing units 2500.1 to 2500.3, after combining the signals of each frequency band by the P / S conversion unit 2700 with respect to the received data, Deinterleaving processing by the deinterleaving unit 4042 and error correction processing by the error correction unit 4040 are executed.

  Here, the synchronization timing signal output from the synchronization processing unit 2600 is used for symbol timing synchronization for detecting the start of an OFDM symbol.

  More generally, the synchronization timing signal output from the synchronization processing unit 2600 is basically used as the synchronization signal in the baseband processing even when the wireless communication systems are different.

  With the configuration as described above, multi-channel simultaneous sensing can be efficiently performed when communication is performed in parallel in a plurality of frequency bands separated from each other. Further, it is possible to perform data transmission by mapping each transmission data to a plurality of frequency bands and adjusting the transmission timing.

  Embodiment disclosed this time is an illustration of the structure for implementing this invention concretely, Comprising: The technical scope of this invention is not restrict | limited. The technical scope of the present invention is shown not by the description of the embodiment but by the scope of the claims, and includes modifications within the wording and equivalent meanings of the scope of the claims. Is intended.

  1000, 1000 ′ transmitter, 1010 S / P converter, 1016, 1020.1 to 1020.3 radio frame generator, 1030 local oscillator, 1040.1 to 1040.3 RF unit, 1050.1 to 1050.3 antenna 1060 channel usage status monitoring unit, 1070 channel usage status prediction unit, 1080 access control unit, 1110 error correction coding unit, 1112 interleave unit, 2000 receiving device, 2011-2010.3 antenna, 2020 local oscillator, 2100. 1-2100.3 receiving unit, 2400.1-2400.3 RF unit, 2500.1-2500.3 baseband processing unit, 2700 P / S conversion unit, 2600 synchronization processing unit, 2800 digital signal processing unit.

Claims (8)

A wireless communication device for performing random access control in each of a plurality of frequency bands separated from each other and transmitting a signal using at least one of a plurality of radio channels of the plurality of frequency bands ,
A digital signal processing unit for generating a digital signal corresponding to the transmission packet;
A plurality of high-frequency signal processing units for converting the digital signal into a high-frequency signal;
A channel usage monitoring unit that performs channel sensing for monitoring the usage of the plurality of radio channels in the plurality of frequency bands;
A sensing target channel is selected from the plurality of radio channels according to a channel sensing result for each predetermined group of the plurality of radio channels by the channel usage monitoring unit, and carrier sense is performed on the selected radio channel. An access control unit that causes a signal to be transmitted from the high-frequency processing unit based on a result of the execution;
Generate prediction information indicating a sensing period in which the selected channels to be sensed are predicted to have a high possibility of being in an idle state based on a prediction based on statistical analysis analysis according to the observed channel usage status A channel usage status prediction unit,
The access control unit performs carrier sense during transmission in the sensing period based on the prediction information, and transmits a signal from the high-frequency processing unit in response to detection of an idle state. . The wireless communication device requests other wireless communication devices to perform channel sensing,
The wireless communication device according to claim 1, wherein the channel usage state observation unit outputs a channel sensing result of itself and a channel sensing result from the other wireless communication device as the usage state. The wireless communication device shares with other wireless communication devices a wireless channel that performs channel sensing for the predetermined group of the wireless channels;
The wireless communication device according to claim 1 or 2, wherein the channel usage state observation unit outputs a channel sensing result of itself and a channel sensing result from the other wireless communication device as the usage state. A wireless communication device for performing random access control in each of a plurality of frequency bands separated from each other and transmitting a signal using a plurality of radio channels in the plurality of frequency bands ,
A digital signal processing unit for dividing transmission data into a plurality of partial data corresponding to each of the plurality of frequency bands, and generating a transmission packet for each of the frequency bands;
A plurality of high-frequency signal processing units provided for each of the frequency bands, for converting the digital signal into a corresponding high-frequency signal for each frequency band;
A local oscillator for generating a clock signal provided in common to the plurality of high frequency processing units and used in the plurality of high frequency processing units;
A channel usage monitoring unit for performing channel sensing for observing channel usage for observing usage of the plurality of radio channels in the plurality of frequency bands;
A sensing target channel is selected from the plurality of radio channels according to a channel sensing result for each predetermined group of the plurality of radio channels by the channel usage monitoring unit, and carrier sense is performed on the selected radio channel. Based on the result of execution, an access control unit that starts transmitting each partial data from the high-frequency processing unit as a packet for each of the plurality of frequency bands synchronously at the same timing;
Generate prediction information indicating a sensing period in which the selected channels to be sensed are predicted to have a high possibility of being in an idle state based on a prediction based on statistical analysis analysis according to the observed channel usage status A channel usage status prediction unit,
The access control unit performs carrier sense during transmission in the sensing period based on the prediction information, and transmits a signal from the high-frequency processing unit in response to detection of an idle state. . The wireless communication device requests other wireless communication devices to perform channel sensing,
The wireless communication device according to claim 4 , wherein the channel usage state observation unit outputs its own channel sensing result and a channel sensing result from the other wireless communication device as the usage state. The wireless communication device shares with other wireless communication devices a wireless channel that performs channel sensing for the predetermined group of the wireless channels;
The wireless communication device according to claim 4 or 5 , wherein the channel usage state observation unit outputs a channel sensing result of itself and a channel sensing result from the other wireless communication device as the usage state. A wireless communication apparatus performing random access control in each of a plurality of frequency bands separated from each other is a wireless communication method for transmitting a signal using at least one of a plurality of wireless channels,
Generating a digital signal corresponding to the transmitted packet;
Converting the digital signal into a high frequency signal;
Performing channel sensing for observing the usage status of the plurality of radio channels for each predetermined group of the plurality of radio channels in the plurality of frequency bands;
Generating prediction information indicating a sensing period in which it is predicted that the selected sensing target channels are likely to be in an idle state in common, based on the prediction by statistical analysis analysis according to the observed usage state When,
A sensing target channel is selected from the plurality of radio channels according to the channel sensing result, and carrier sense at the time of transmission is executed for the selected radio channel in the sensing period based on the prediction information. And a step of transmitting the high-frequency signal in response to detection of an idle state . A wireless communication device performing random access control in each of a plurality of frequency bands separated from each other is a wireless communication method for transmitting a signal using a plurality of wireless channels,
Dividing transmission data into a plurality of partial data corresponding to each of the plurality of frequency bands, and generating a transmission packet for each of the frequency bands;
For each frequency band, converting the digital signal into a corresponding high frequency signal for each frequency band;
Generating a clock signal for processing to be converted into the high-frequency signal by a local oscillator provided in common in the plurality of frequency bands;
Performing channel sensing for observing the usage status of the plurality of radio channels for each predetermined group of the plurality of radio channels in the plurality of frequency bands;
Generating prediction information indicating a sensing period in which it is predicted that the selected sensing target channels are likely to be in an idle state in common, based on the prediction by statistical analysis analysis according to the observed usage state When,
A sensing target channel is selected from the plurality of radio channels according to the channel sensing result, and carrier sense at the time of transmission is executed for the selected radio channel in the sensing period based on the prediction information. And, in response to detection of an idle state , starting to transmit the high-frequency signal in synchronization with each partial data as a packet for each of the plurality of frequency bands at the same timing. .