JP2019176254A - Channel state prediction device, channel state prediction method, radio communication device, and radio communication method - Google Patents

Abstract

To provide a radio communication device which can map transmission data to a plurality of frequency bands, and perform a data transmission by adjusting a transmission timing when a communication is performed in parallel in the plurality of frequency bands separated each other at the same time.SOLUTION: A transmission apparatus 1000 transmits a signal by using a plurality of radio channels that performs a random access control in each of a plurality of frequency bands separated each other. A channel using state prediction part 1070 generates prediction information by predicting a channel using state at the next time point by an autoregression model in response to a plurality of measurement time points to be categorized in accordance with the using state observed. An access control part 1080 transmits each partial data as a packet in each of the plurality of frequency bands by the plurality of radio channels so as to be synchronized at the same timing.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a channel state prediction device, a channel state prediction method, a wireless communication device using the same, and a wireless communication method.

  Conventional wireless communication systems such as LTE (Long Term Evolution) Release 8 (Rel-8), which is a wireless communication system standardized by 3GPP (3rd Generation Partnership Project), communicate using a bandwidth of up to 20 MHz. Can be done.

  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. A carrier aggregation (CA) technique that uses a plurality of component carriers (CC) bundled at the same time is adopted, and a wide band 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 mobile terminals such as smartphones.

  As a result, in addition to the expansion of the use of the conventional wireless LAN (Local Area Network), 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 band (2.4 GHz band, 5 GHz band) ) Traffic has increased rapidly.

  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 status of radio resources varies depending on time, place, frequency band, radio channel, and the like, a situation in which only some frequency bands (or radio channels) are 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, IEEE802.11n is used after setting which of 2.4 GHz band and 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 technique 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.

  However, it is not always clear what data should be distributed and how the transmission timing should be determined when communicating in parallel in a plurality of mutually separated frequency bands.

  Therefore, the usage status (such as the availability of each radio channel) of multiple frequency bands (one or more radio channels in each frequency band) is observed, and the transmission timing and usage are based on such observation results. It is conceivable to control the radio channel. Specifically, the timing of transmission and the radio channel to be used are determined according to how long each radio channel is available or from when.

  However, for such transmission control, it is necessary to predict the future usage status from past observation results.

  At this time, in consideration of frequently predicting the availability and busy probability every time frame transmission is attempted, the prediction algorithm needs to maintain a low calculation amount and good accuracy.

  It is considered that the radio resource utilization pattern is complicated under the situation where many radio apparatuses perform radio transmission and various communication traffic is mixed. Modeling with a simple expression for such a situation is very difficult. Therefore, the design of prediction algorithms and the reduction of complexity are important issues.

  Here, as a conventional technique for predicting the use situation of wireless communication, there are the following.

  Non-Patent Document 1 proposes a radio resource utilization rate (COR: channel occupation ratio) prediction algorithm based on the AR (autoregressive) method. However, no reference is made to predicting the probability of occurrence of the busy / idle state duration on the real time axis.

  In Non-Patent Document 2, traffic is modeled using a hidden Markov model, and COR is predicted. In Non-Patent Document 3, COR analysis and prediction are performed using an autoregressive integrated moving average (ARIMA) model. However, the occurrence / probability of busy / idle start / end timing and duration is not predicted.

  In Non-Patent Document 4, a wireless channel usage model is examined based on actual measurement results. It also outlines the channel status prediction method. However, an effective prediction method regarding the start / end timing of busy / idle is not shown.

JP 2011-111433 A

JP 2013-187561 A

S. Kaneko, S. Nomoto, T. Ueda, S. Nomura, and K. Takeuchi, “Predicting radio resource availability in cognitive radio-an experimental examination,” in Proc. CrownCom, Singapore, pp. 1-8, May 2008.

E. Chatziantoniou, B. Allen and V. Velisavljevie, “An HMM-based spectrum occupancy predictor for energy efficient cognitive radio,” IEEE PIMRC, London, pp. 601-605, Sept. 2013.

Z. Wang and S. Salous, “Spectrum occupancy statistics and time series models for cognitive radio,” J. Signal Process. Syst., Vol. 62, no. 2, pp. 145–155, Feb. 2011.

Y. Chen and H.S. Oh, "A Survey of Measurement-Based Spectrum Occupancy Modeling for Cognitive Radios," IEEE Communications Surveys & Tutorials, vol. 18, no. 1, pp. 848-859, First quarter 2016.

  However, as described above, in order to simultaneously communicate in a plurality of frequency bands separated from each other, the use situation of the plurality of frequency bands is observed, and one or more instantaneously unused based on the observation result It is necessary to transmit radio frames simultaneously in different frequency bands and radio channels. In this case, the data is mapped to a plurality of bands and transmitted, and the receiving side is configured to collectively receive the plurality of bands and integrate the data.

  In this way, transmission opportunities can be ensured even if there is a bias in the congestion situation between the bands, so that improvement in frequency utilization efficiency and reduction in transmission delay can be expected, and there is no problem of changing the arrival order of data.

  However, in order to perform efficient frame transmission using multiple frequency bands, it is important to appropriately determine the timing of transmission and the radio channel to be used. Needs to be predicted with high accuracy. For this reason, an effective prediction method regarding the start / end timing of the channel empty / blocked state (idle / busy) is required for each frequency band based on the observation result of the usage situation of a plurality of frequency bands.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to use a plurality of frequency bands when communication is performed simultaneously in a plurality of frequency bands separated from each other. A channel state prediction device, a channel state prediction method, a wireless communication device using the same, and a wireless communication capable of effectively predicting the start / end timing of the channel empty / blocked state for each frequency band from the observation results Is to provide a method.

  According to one aspect of the present invention, there is provided a channel state prediction apparatus for predicting the duration of a busy state and an idle state of a wireless channel performing random access control in a target frequency band. A channel usage monitoring unit that observes channel usage at multiple measurement points, and an autoregressive model for multiple measurement points according to the observed usage, predicts channel usage at the next point in time. A channel use state prediction unit that generates prediction information.

  Preferably, the channel usage state prediction unit determines a busy / idle state of a radio channel and measures a busy / idle state duration and a busy / idle duration specific time. A busy / idle duration categorizing unit that categorizes busy / idle durations obtained by setting the number of busy / idle durations acquired by the busy / idle duration acquisition unit corresponding to any of the specific times, and categorizing For each transition pattern of the categorized busy / idle duration, learn the parameters of the autoregressive model prediction formula independently and use any of the learned parameters according to the categorized busy / idle duration history And select the next business using the selected parameter. / Predicting the idle occurrence time and calculating the prediction error occurrence probability for the measurement value measured by the channel usage monitoring unit, and the next busy / idle continuation based on the prediction error occurrence probability A duration occurrence probability prediction unit for predicting the occurrence probability of time.

  According to another aspect of the present invention, there is provided a channel state prediction method for predicting a busy state and an idle state duration of a wireless channel that is performing random access control in a target frequency band. Predicting channel usage at the next time point based on the step of observing channel usage at multiple time points and autoregressive models for multiple time points according to the observed usage state And a step of performing.

  According to still another aspect of the present invention, there is provided a radio communication apparatus for transmitting a signal using a plurality of radio channels performing random access control in each of a plurality of frequency bands separated from each other, wherein A digital signal processor for dividing the data into multiple partial data corresponding to each of multiple frequency bands and generating a transmission packet for each frequency band, and a digital signal provided for each frequency band A plurality of high-frequency signal processing units for converting to a high-frequency signal for each frequency band to be used, a channel usage state observation unit for observing the usage status of a radio channel at a plurality of measurement points in a plurality of frequency bands, and the observed usage state Depending on the channel, an autoregressive model for multiple measurement points predicts the channel usage at the next point and generates prediction information. Based on the usage status prediction unit and the prediction information, the digital signal processing unit and the high frequency processing unit are controlled, and each partial data is synchronized as a packet for each of a plurality of frequency bands by a plurality of radio channels at the same timing And an access control unit for transmission.

  Preferably, the channel usage state prediction unit determines a busy / idle state of a radio channel and measures a busy / idle state duration and a busy / idle duration specific time. A busy / idle duration categorizing unit that categorizes busy / idle durations obtained by setting the number of busy / idle durations acquired by the busy / idle duration acquisition unit corresponding to any of the specific times, and categorizing The parameters of the autoregressive model prediction formula are learned independently for each transition pattern of the categorized busy / idle duration, and the following parameters are learned using the categorized busy / idle duration history. Predict busy / idle occurrence time and observe channel usage A duration prediction error probability acquisition unit that calculates a probability of occurrence of a prediction error with respect to a measurement value obtained by the method, a duration occurrence probability prediction unit that predicts the probability of occurrence of the next busy / idle duration based on the probability of occurrence of a prediction error, and ,including.

  Preferably, the duration prediction error probability acquisition unit executes a process of updating a parameter of the prediction formula according to a traffic situation.

  According to still another aspect of the present invention, there is provided a radio communication method for transmitting a signal using a plurality of radio channels performing random access control in each of a plurality of frequency bands separated from each other. Dividing 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 digital signal for each frequency band, a high-frequency signal for each corresponding frequency band A step of observing the usage status of the radio channel in a plurality of frequency bands at a plurality of measurement points, and an autoregressive model by the above-described categorization process for a plurality of measurement points according to the observed usage situation. Predicting the channel usage status at the next time point and generating prediction information, and based on the prediction information, The radio channels, each partial data as packets for a plurality of frequency bands, and transmitting at the same timing in synchronization.

  According to the present invention, based on the observation results of the usage status of a plurality of frequency bands, prediction regarding the start / end timing of the channel busy / idle state is effectively performed for each frequency band, and transmission data is mapped to the plurality of frequency bands. In addition, data transmission can be performed by adjusting the transmission timing.

It is a conceptual diagram for demonstrating the structure of the radio | wireless communications system of this Embodiment. 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. It is a functional block diagram for demonstrating the structure of the transmitter 1000 of this Embodiment. 10 is a timing chart for explaining operations of a channel usage status observation unit 1060, a channel usage status prediction unit 1070, and an access control unit 1080. 10 is a flowchart for explaining operations of a channel usage status observation unit 1060, a channel usage status prediction unit 1070, and an access control unit 1080 of the transmission apparatus 1000. FIG. 10 is a functional block diagram illustrating a configuration for predicting the occurrence probability of busy / idle duration in channel usage status prediction section 1070. It is a conceptual diagram for demonstrating the AR prediction method using the categorization of Busy / Idle duration. It is a conceptual diagram for demonstrating an autoregressive model method. It is a conceptual diagram for demonstrating the procedure which acquires a busy / idle continuation time. It is a conceptual diagram which shows the procedure which learns the parameter of a prediction formula. It is a flowchart which shows the procedure of prediction of a busy / idle continuation probability. It is a communication data collection system block diagram for prediction process experiments. It is a figure which shows the complementary cumulative distribution function of an idle prediction error. It is a figure which shows the prediction result of the generation | occurrence | production probability of the next idle continuation time. It is a functional block diagram for demonstrating the example of a more detailed structure of the transmitter 1000. FIG. 3 is a functional block diagram for explaining a configuration of a receiving device 2000. FIG. 3 is a functional block diagram for explaining an example of a more detailed configuration of receiving apparatus 2000. FIG.

  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.

  However, the wireless communication apparatus of the present invention is not necessarily limited to such a case, and more generally, using a plurality of frequency bands separated from each other at the same time in synchronization with the same wireless method. It is possible to apply to a receiving apparatus that performs communication. 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.

  In the present embodiment, as described below, modeling and prediction methods based on machine learning are used together to enter channel busy / idle states (idle / busy) in each frequency band / channel in an actual environment. Predicting the time to provide a probability distribution for the duration of the busy / idle state. In addition, the probability distribution calculation method for the busy / idle state duration time can be applied to a configuration in which communication is performed using at least one of a plurality of frequency bands.

  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.

  FIG. 1 is a conceptual diagram for explaining the configuration of the wireless communication system of the present embodiment.

  Referring to FIG. 1, on the assumption that the transmission side uses three frequency bands of 920 MHz band, 2.4 GHz band, and 5 GHz band, 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 this embodiment, radio access control having the following characteristics is performed.

  That is, first, on the transmission side, the usage status (such as availability of each radio channel) of a plurality of frequency bands is observed 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. 2 is a diagram for explaining a specific example for mapping transmission data to a plurality of bands and transmitting them, and collectively receiving and integrating them on the receiving side.

  As shown in FIG. 2, 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.

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. 3 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 according to the present embodiment.

  Referring to FIG. 3, transmission apparatus 1000 performs error correction coding section 1110 for performing error correction coding processing on a transmission data sequence, and interleave processing for data after error correction coding. For the interleaving unit 1112 to be performed, the serial / parallel conversion (hereinafter referred to as S / P conversion) unit 1010 for performing processing assigned to each frequency band as described in FIG. 2, and the data after S / P conversion, Radio frame generation units 1020.1 to 1020.3 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 And digital-analog conversion processing and predetermined conversion for the digital signals from the radio frame generation units 1020.1 to 1020.3, respectively. RF processing units (RF units) 1040.1 to 1040.3 for performing modulation processing (for example, orthogonal modulation processing for a predetermined multi-level modulation method), up-conversion processing, power amplification processing, and the like, and RF And antennas 1050.1 to 1050.3 for transmitting the high-frequency signals of the 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.

  Here, it is assumed that the channel usage state monitoring unit 1060 performs the above-described carrier sense 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.

  An example of detailed operation of the channel usage status prediction unit 1070 will be described later.

  As described with reference to FIG. 2, 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. 4 is a timing chart for explaining operations of the channel usage status observation unit 1060, the channel usage status prediction unit 1070, and the access control unit 1080.

  Referring to FIG. 4, channel usage status monitoring section 1060 observes the usage status of each frequency band (for example, the availability status and busy probability of each radio channel), and channel usage status prediction section 1070 The most recent usage situation is predicted, and from the result, the access control unit 1080 determines transmission parameters such as a transmission timing, a used frequency band and a radio channel so that good communication can be performed.

  That is, as will be described in detail later, for example, when performing communication using three frequency bands, the channel usage state prediction unit 1070 uses two bands at the time t2, for example, based on the current time. If it is time t3, it is predicted that three bands can be used. In order to perform efficient transmission, the access control unit 1080 determines the transmission start timing and the used frequency band based on the use state prediction result.

  For example, in conventional random access control in a wireless LAN or the like, transmission is performed immediately when a transmission opportunity is obtained by CSMA / CA and random backoff.

On the other hand, the access control unit 1080 according to the present embodiment waits for transmission until a plurality of frequency bands / wireless channels can be used simultaneously even if a transmission opportunity is obtained on some of the wireless channels as necessary. Control is performed.
(Configuration and operation of channel usage state prediction unit 1070)
Hereinafter, the configuration and operation of the channel usage status prediction unit 1070 will be described.

  The channel usage status prediction unit 1070 receives information to be observed / measured as radio channel usage status as input, calculates usage status statistics for each radio channel calculated from the observation / measurement results, and determines transmission start timing. Calculate necessary usage information.

  Examples of items observed / measured as the wireless channel usage status and usage status statistics of each wireless channel calculated from the observation / measurement results are as follows.

i) Status of each radio channel (busy or idle: physical carrier sense result)
ii) Busy duration of each radio channel ii-1) Frame length described in the physical header of the frame being received ii-2) NAV value (virtual carrier sense) described in the MAC header of the frame being received result)
NAV is a Network Allocation Vector (transmission prohibited period).

  Examples of usage statistics for each wireless channel calculated from the observation and measurement results are as follows.

i) Probability of becoming busy (time utilization rate)
ii) Probability distribution of duration of busy and idle states (The derivation method will be described later)
iii) Probability distribution of the duration of the idle / busy state relative to the previous busy / idle state duration (for example, probability density function (PDF) or cumulative distribution function (CDF))
iv) Busy state and idle state occurrence pattern (period and duty ratio: when background traffic is periodic)
For the explanation of terms, a general method for avoiding transmission collision from each terminal in a wireless LAN will be briefly described.

  A wireless LAN channel employs a method called “CSMA (Carrier Sense Multiple Access)” because packets cannot collide and efficient communication cannot be established unless they wait for transmission from each other.

  In the case of wireless, it is not known whether or not a collision will occur just by monitoring the intensity of radio waves. This is because radio waves are greatly attenuated depending on the distance, so that there is a possibility that the radio waves cannot be detected if the opponent causing the collision is far away.

  Therefore, a “waiting time (DIFS: Distributed access Inter Frame Space)” is always provided before transmission, and transmission is performed after confirming that there is no other transmission signal. Such a method is called “CA (Collision Avoidance)”.

  And after transmission, it always waits for "ACK (ACKnowledgement, arrival confirmation response)", and when ACK does not return, it judges that a collision etc. have occurred and retransmits.

  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 all wireless devices send out an “RTS (transmission request)” packet before transmission and respond with “CTS (receivable)” if the receiving side can also receive the packet. In the above example, terminal C first transmits RTS to access point B. However, this RTS does not reach the terminal A.

  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 will be performed, and postpones transmission. In the RTS / CTS packet, the channel occupation period is written, and communication is suspended during that time. This period is called “NAV (Network Allocation Vector)”.

  FIG. 5 is a flowchart for explaining the operations of channel usage status observation unit 1060, channel usage status prediction unit 1070, and access control unit 1080 of transmission apparatus 1000 described in FIG.

  Referring to FIG. 5, first, channel usage status observation section 1060 performs carrier sense in a plurality of bands, calculates usage status information, and updates usage status information stored in a storage device (not shown) ( S100).

  That is, the channel usage state monitoring unit 1060 measures the busy / idle state of each radio channel scheduled to be used in a plurality of frequency bands, and measures the durations thereof.

  The access control unit 1080 determines whether there is data to be transmitted (S102). If there is no data to be transmitted yet (No in S102), the process returns to S100.

  On the other hand, when there is data to be transmitted (Yes in S102), the access control unit 1080 first determines whether or not the “immediate transmission condition” described below is satisfied for the wireless channel from which the transmission opportunity is obtained. .

  That is, originally, the access control unit 1080 determines whether or not the transmission timing has arrived based on the prediction result of the channel usage state prediction unit 1070, but in reality it is in a busy / idle state. For example, if it is determined that a combination of the following conditions is satisfied for a radio channel for which a transmission opportunity has been ensured, an error may occur in the prediction of the occurrence of the transmission opportunity, and the transmission opportunity may not be obtained as expected. Then, control is started to start transmission immediately (S104). That is, in this case, if the access control unit 1080 determines that the predetermined communication quality can be achieved by performing transmission using the radio channel that has obtained the transmission opportunity, the access control unit 1080 immediately does not wait for the transmission timing based on the prediction result. To perform wireless transmission.

a1) The total transmission rate is greater than or equal to a predetermined value a2) When transmission is started immediately, the transmission delay of transmission data is less than a predetermined value a3) When transmission is started immediately, the throughput increases by a predetermined amount or more a4) A transmission opportunity is secured When transmission is performed on a wireless channel, the variance and / or average of the usage rate between the wireless channels is reduced. A5) When transmission is performed on a wireless channel where a transmission opportunity is secured, the energy consumption required for transmission is less than a predetermined amount. A6) A transmission opportunity is obtained on a predetermined radio channel a7) When loss of transmission opportunity is not allowed Any one of the above conditions a1) to a7) is satisfied, or conditions a1) to a7 ) Is established (a combination of two or more conditions), the access control unit 1080 immediately transmits using a radio channel for which a transmission opportunity is secured. Start. That is, the access control unit 1080 performs transmission parameter determination and transmission data mapping (S108), and controls the S / P conversion unit 1010 and the radio frame generation units 1020.1 to 1020.3 to select the selected frequency. The frame is transmitted on the band and the wireless channel (S110), and the process returns to step S100.

  Here, as the “transmission parameters”, in the case of “used band and used radio channel”, “transmission rate used in each radio channel”, “each radio channel (orthogonal frequency division multiplexing (OFDM)) Transmission power for each subcarrier).

  If predetermined conditions are satisfied, it may be possible to perform transmission using only a part of radio channels instead of radio channels in all usable frequency bands.

  For determining the transmission rate and the transmission power, existing methods as described in the following documents can be used.

Literature: Tomoaki Yoshinori, Seiichi Sampei, Norihiko Morinaga, “OFDM adaptive modulation using multilevel transmission power control for high-speed data transmission,” IEICE Transactions (B), J84-B, 7, pp. 1141-1150, July 2001 The propagation path information necessary for determining the transmission rate and transmission power can be obtained by the following method, for example.

    i) The propagation path estimation result performed when receiving the frame received by the reverse communication is used.

    ii) A propagation path feedback method defined in IEEE 802.11 wireless LAN is used.

Subsequently, when the “immediate transmission condition” is not satisfied (N in S104), the access control unit 1080 determines whether or not the transmission timing has arrived based on the prediction result of the channel usage state prediction unit 1070 as described above. Determine (S106)
For the determination of the transmission start timing, prediction information based on usage status information is used as follows.

b1) Prediction of time required for a wireless channel in a busy state to enter an idle state (prediction of “how long should I wait?”)
For this, the following information can be used to predict “how long should I wait?”.

b1-1) Length of frame or NAV that is busy (if already known)
b1-2) Presence / absence of busy state of each radio channel after an arbitrary time (For periodic background traffic, from busy state and idle state period and duty) Predictable)
b1-3) Probability of idle occurrence with respect to waiting time in the future based on categorized busy / idle duration (busy state and idle state) (Calculated from complementary cumulative distribution function (CCDF))
b2) Prediction of the time required for an idle radio channel to become busy (Prediction of "How long can I wait?")
b2-1) Presence / absence of busy state of each radio channel after an arbitrary time (If it is periodic background traffic, it can be predicted from the period and duty of busy state and idle state)
b2-2) Busy occurrence probability (busy state and idle state) with respect to future waiting time based on the past categorized idle (idle) / idle (idle) duration Can be calculated from the complementary cumulative distribution function (CCDF)
The access control unit 1080, as described above, “prediction of the time required for a radio channel in a busy state to become an idle state” and “an idle radio channel is busy. By combining with the “prediction of required time to become”, the transmission timing “maximum expected value of transmission rate” is calculated.

  That is, the access control unit 1080 combines the above two predictions so that the transmission rate of each radio channel has a predetermined value, and the idle state at each time timing within a predetermined time range from the present time. The maximum value of the amount of data that can be transmitted through the wireless channel can be predicted. When such predicted data amount (transmission rate) that can be transmitted exceeds a value corresponding to a predetermined transmission rate, data is transmitted at the transmission timing.

  That is, if the access control unit 1080 determines that such transmission timing has arrived (Yes in S106), the access control unit 1080 determines transmission parameters and maps transmission data (S108), and performs S / P conversion. The unit 1010 and the radio frame generation units 1020.1 to 1020.3 are controlled to transmit a frame using the selected frequency band and radio channel (S110), and the process returns to step S100.

  When the access control unit 1080 determines in step S106 that the predicted transmittable data amount (transmission rate) does not exceed the value corresponding to the predetermined transmission rate, the access control unit 1080 waits for transmission to increase the current amount. Assuming that there is a possibility that a transmission opportunity may be obtained with the number of wireless channels, transmission is waited (No in step S106), and the process returns to step S100. This is because such a standby operation is considered to achieve improvement in frequency utilization efficiency, reduction in transmission delay, and the like.

  Note that the access control unit 1080 may adopt the following as a reference for determining whether or not the transmission timing has arrived.

c1) Minimize the time until transmission of transmission data is completed (since transmission can be completed early, many frames can be transmitted and less resources are wasted)
c2) Minimize the amount of free resources generated until the completion of transmission c3) Maximize the amount of data that can be transmitted within a predetermined time c4) Minimize the variance and average of the usage rate of each radio channel (Effective use of radio resources) While eliminating extremely crowded channels.)
c5) Minimize the required transmission energy under the condition that transmission of transmission data is completed within a certain period of time c6) The probability of transmission outage (transmission failure / transmission opportunity loss) is below a predetermined value c7) Use of a specific radio channel by itself Rate is less than the specified value (In order to keep the time utilization rate of the frequency band within the limit in a frequency band with a transmission time limit such as the 920 MHz band.)
(Busy / idle duration occurrence probability prediction)
Hereinafter, a procedure for predicting the occurrence probability of the busy / idle duration by the channel usage state prediction unit 1070 will be described.

  FIG. 6 is a functional block diagram illustrating a configuration for predicting the occurrence probability of the busy / idle duration time in the channel usage state prediction unit 1070.

  The channel usage status prediction unit 1070 determines the busy / idle state of the channel based on the information from the channel usage status observation unit 1060, and measures the duration time of the busy / idle state. A busy / idle duration categorizing unit 1074 that performs categorization using a combination of busy / idle durations that defines the busy / idle durations acquired by the busy / idle duration acquisition unit 1072, and a categorized busy / idle Learning the parameters of the prediction formula described later with the duration, predicting the next busy / idle occurrence time using the learned parameters, and evaluating the occurrence probability P (Err) of the prediction error with respect to the measured value The probability acquisition unit 1076 and the next busy / idle duration And a duration probability prediction unit 1078 predicts the raw probability R (X + Err).

  Hereinafter, the operation of each unit of the channel usage status prediction unit 1070 will be described.

  First, as a premise, the channel usage situation prediction unit 1070 has one or more time ranges defined in advance for each of the busy duration and idle duration for the busy / idle duration acquired by the busy / idle duration acquisition unit 1072. Accordingly, the busy / idle duration categorizing unit 1074 performs categorization.

FIG. 7 is a conceptual diagram for explaining an AR prediction method using categorization of Busy / Idle duration time. The categorization procedure can be summarized as follows.
1) The busy / idle duration acquired by the busy / idle duration acquisition unit 1072 is classified into subsets according to a predetermined time range.
2) The coefficient learning of the AR method is performed for each transition pattern indicating which subset is the busy / idle duration of the past K layer. If the number of subsets that categorize the busy / idle duration is, the transition pattern becomes and holds all AR coefficient sets.
3) After learning is completed over a certain period of time, the AR method coefficient set to be used is determined according to the transition pattern of the observed busy / idle duration and past busy / idle duration. / Predict the idle duration.
4) Next, the next busy / idle duration is predicted by the AR method from the channel use duration and the AR method coefficient.
Next, the channel usage state prediction unit 1070 performs busy / idle duration prediction based on an autoregressive model (AR) method.

Here, in the AR method, the next busy / idle duration is predicted from the most recent p busy / idle durations X _{i ,.}

  Here, when the previous channel state is busy (Xi is the idle duration), the idle duration is predicted as Xi + 1, and the immediately previous channel state is idle (Xi is busy duration). ), The busy duration is predicted as Xi + 1.

The coefficient a ₀ of the above prediction equation (p order), ..., a _p learns using the training interval.

  The procedure for predicting the probability of occurrence with respect to the busy / idle duration is briefly summarized as follows.

  1) Get busy / idle duration by sensing.

  2) Learn the parameters of the prediction formula with the acquired busy / idle duration.

  3) The next busy / idle occurrence time X is predicted using the learned parameters.

  4) Evaluate the occurrence probability P (Err) of the prediction error for the measured value.

  5) Predict the next busy / idle duration occurrence probability R (X + Err) with the following formula:

  FIG. 8 is a conceptual diagram for explaining the autoregressive model method.

In an autoregressive model for time series prediction, the parameters (AR coefficients (coefficients a ₁ ,..., A _p ) and prediction error variances) obtained from the sample time series obtained (the autocovariance function estimated therefrom) Ask from. Here, the Levinson-Durbin algorithm, which is a fast algorithm for solving the Yule-Walker equation that satisfies the autocovariance function, is generally used.

  Such a procedure is a well-known procedure as disclosed in Non-Patent Document 1 described above, for example.

  Note that prediction based on machine learning other than the AR method may be used for the busy / idle duration prediction method. For example, Markov Chain HMM (Markov Chain based HMM) prediction method, autoregressive moving average prediction method (ARMA prediction method, ARMA: Autoregressive moving average). Here, the ARMA prediction method is disclosed in Non-Patent Document 4.

  Hereinafter, the procedure of the autoregressive model method will be described in more detail.

  (1) The busy / idle duration acquisition unit 1072 acquires the busy / idle durations categorized according to the busy / idle duration time range that defines the busy / idle durations acquired.

  FIG. 9 is a conceptual diagram for explaining a procedure for acquiring the busy / idle duration time.

  The channel usage state monitoring unit 1060 performs carrier sense in each band / channel, and the busy / idle duration acquisition unit 1072 performs channel busy / idle determination. Further, the busy / idle duration acquisition unit 1072 measures the duration of busy / idle based on the busy / idle determination result. The measurement may be continuous time or may be a discrete value in units of a certain width for the purpose of information compression. Then, the busy / idle duration categorizing unit 1074 categorizes the busy / idle duration according to the busy / idle duration time range that defines the busy / idle duration acquired by the busy / idle duration acquisition unit 1072.

  For example, FIG. 9 shows an example of processing with discrete values in units of 9 μs, which is the contention slot length, assuming WLAN. In this case, the busy state or idle duration can be expressed by the number of points in this unit time. In the example of FIG. 9, this corresponds to 1 point = 9 μs. In the following, time is expressed using points.

(2) The parameters a ₁ ,..., A _p of the prediction formula are learned from the categorized busy / idle duration sequence.

  FIG. 10 is a conceptual diagram illustrating a procedure for learning parameters of a prediction formula.

Subsequently, the duration prediction error probability acquisition unit 1076 learns parameters a ₁ ,..., A _p from N duration measurement results for busy / idle. Therefore, no special data needs to be transmitted for learning.

As described above, the duration prediction error probability acquisition unit 1076 calculates the parameters a ₁ ,..., A _p by solving the normal equation generated from the least square equation using the Levinson-Durbin induction method.

  (3) The next busy / idle occurrence time X is predicted using the learned parameters.

The next busy / idle occurrence time X (= X _{i + 1} ) is predicted by the above-described prediction method of the AR method using the coefficients a ₁ ,..., A _p obtained from the learning results.

  (4) Evaluate the occurrence probability P (Err) of the prediction error for the measurement value, which is a complementary cumulative distribution function (CCDF) of the occurrence probability of the prediction error Err.

  Here, the following relationship holds.

(5) The next busy / idle duration X _new occurrence probability R (X _new ) is predicted from the busy / idle duration predicted result X and the prediction error occurrence probability P (Err).

The duration occurrence probability prediction unit 1078 predicts the occurrence probability R ^B (X ^B _new ) and R ^I (X ^I _new ) of the next busy / idle duration by the following procedure.

Based on the occurrence probability R ^B (X ^B _new ) and R ^I (X ^I _new ) of the next busy / idle duration calculated as described above, the access control unit 1080 determines whether or not to transmit now. "?"

  FIG. 11 is a flowchart showing a procedure for predicting the busy / idle continuation probability.

  First, the channel usage monitoring unit 1060 measures the busy / idle duration by carrier sense, and the busy / idle duration acquisition unit 1072 acquires the busy / idle duration (S200).

Subsequently, the busy / idle duration categorizing unit 1074 performs categorization of the busy / idle duration (S202), and if the prediction formula parameter corresponding to the categorized busy / idle duration is being learned / updated ( In step S204, the duration prediction error probability acquisition unit 1076 learns the parameters a ₁ ,..., A _p from the N duration measurement results of busy / idle, updates the prediction formula (S206), and performs processing. Returns to step S200.

  On the other hand, if the prediction formula parameter is not being learned / updated (No in S204), the duration prediction error probability acquisition unit 1076 determines whether the prediction formula parameter needs to be updated (S210).

  Here, the case where the prediction formula parameter needs to be updated includes, for example, the following cases.

  i) When the number of active terminals (the number of terminals transmitting / receiving data) changes.

  ii) When new traffic occurs or transmission of some traffic is terminated.

iii) When the MCS to be used is changed. (Because the distribution of busy duration changes.)
iv) When the variance of the busy / idle duration prediction error becomes larger than a predetermined amount (or ratio) compared to when learning is completed.

  Here, MCS (Modulation and Coding Scheme) represents a modulation scheme and a channel coding rate. In order to change the transmission rate according to the state of the communication path, generally, a combination of different modulation schemes and channel coding rates is prepared as a table.

  Returning to FIG. 11 again, when the prediction formula parameter needs to be updated (Yes in S210), the process returns to Step S200.

  On the other hand, when the prediction formula parameter does not need to be updated (No in S210), the duration prediction error probability acquisition unit 1076 confirms the wireless channel state, and if busy (Yes in S212), the duration of the busy state (S214), if it is idle (No in S212), the duration of the idle state is predicted (S216).

  Here, prediction of busy / idle duration is performed alternately. For example, if the immediately preceding state is busy, the idle duration is predicted.

  Further, the duration prediction error probability acquisition unit 1076 uses the predicted value of busy / idle duration calculated in step S214 and step 216 and the busy / idle duration measured by carrier sense in step S200. Then, an error (prediction error) between the predicted value and the actual value is calculated (S218).

  Further, the duration prediction error probability acquisition unit 1076 updates the complementary cumulative distribution function (CCDF) of the busy / idle duration prediction error based on the calculated prediction error (S220). Here, the CCDF of the prediction error is stored separately in busy and idle in a storage unit (not shown).

Based on the updated complementary cumulative distribution function (CCDF) and busy / idle duration prediction, the duration occurrence probability predicting unit 1078 calculates usage status information necessary for determining the transmission start timing (S222). / Idle duration occurrence probabilities R ^B (X ^B _new ) and R ^I (X ^I _new ) are calculated, and the occurrence probabilities for the busy / idle duration are output to the access control unit 1080 (S224).
(Results of measurement and prediction experiments)
FIG. 12 is a configuration diagram of a communication data collection system for prediction processing. Using the system shown in the communication data collection system configuration diagram in FIG.
The present invention is used for the collected communication data to calculate the complementary cumulative distribution function (CCDF) of the duration prediction error for the busy state and the idle state, and predict the occurrence probability of the busy and idle durations.

Here, sensing is performed every 9 μs, and various settings necessary for categorizing busy / idle duration are 2 types of idle duration subsets: less than 1 ms (set1), 1 ms or more (set2). Duration subset: Two types of busy / idle duration subset layers of less than 0.5 ms (set 1) and 0.5 ms or more (set 2): Assume that there are 5 layers. Therefore, it is assumed that the total data stream is 2 × 2 × 2 × 2 × 2 = 32.
Subsequently, it is assumed that training data for calculating the parameters a ₁ ,..., A _p of the AR method is 200 samples (N = 100). Further, the order (p = 2) is adopted as the order of the prediction formula.

  FIG. 13 is a diagram showing a calculation result of a complementary cumulative distribution function of an idle prediction error when the present invention is used for data collected by the communication data collection system of FIG. is there.

In the idle state data required at the time of transmission, compared with the case where AR prediction is performed without performing customization, the prediction error is four types of randomly selected data streams S1: busy (set2) -idle (set1)- Busy (set1)-Idle (set1)-Busy (set1)
S2: Busy (set2)-Idle (set1)-Busy (set2)-Idle (set1)-Busy (set1)
S3: Busy (set2)-Idle (set2)-Busy (set1)-Idle (set1)-Busy (set1)
S4: Busy (set2)-Idle (set2)-Busy (set2)-Idle (set1)-Busy (set1)
As a result, the prediction error is improved due to the categorization effect.

  FIG. 14 is a diagram showing a result of predicting the probability of occurrence of the next idle duration based on the result of FIG.

Two types of data streams from the four types of data streams in FIG.
S1: Busy (set2)-Idle (set1)-Busy (set1)-Idle (set1)-Idle prediction value at busy (set1) is 500 points S2: Busy (set2)-Idle (set1)-Busy (set2) -Idle (set1)-The estimated idle value in busy (set1) is assumed to be 400 points, and the probability that data transmission requiring 400 points in S1 can be executed is about 97%.
[Configuration of wireless communication device]
FIG. 12 is a configuration diagram of a communication data collection system for prediction processing.

In order to collect communication data for prediction processing in the main terminal stations in Japan, the antenna 170 receives various types of radio waves flying in the terminal station, and the filtering function of the bandpass filter 160 allows 920 MHz / 2. Only the 4 GHz / 5 GHz band radio wave is received, and the low noise amplifier 150 prevents the mixing of noise and reinforces the radio wave reception intensity. Next, each radio wave in the 920 MHz / 2.4 GHz / 5 GHz band is demodulated as experimental data by the wireless receiver 140, and the experimental data collection control device 120 receives this experimental data, and each of the 920 MHz / 2.4 GHz / 5 GHz band Analyzing the busy / idle duration of a channel and executing processing according to various algorithms related to the present invention, predicting the next busy / idle duration, and creating the wireless channel information group for simultaneous transmission of multiple frequency bands according to the present invention .
The display device 110 is a display processing device typified by a liquid crystal display or the like. Necessary information can be visually confirmed by operating the input operation device 130, that is, an input operation processing device typified by a keyboard, a touch panel, a mouse, or the like. To do. [Configuration of wireless communication device]
FIG. 15 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. 15 shows a configuration of a transmission device according to the same wireless communication scheme as the wireless communication standard 802.11a as an example.

  That is, although the wireless communication standard 802.11a is a wireless LAN communication system of 5 GHz band, in FIG. 15, 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. 15 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. 15, 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.

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 own station, and the channel usage status prediction unit 1070 The most recent usage situation is predicted, and the access control unit 1080 controls transmission timing accordingly.
[Receiver configuration]
Hereinafter, the configuration of the receiving apparatus used in the wireless communication system as described with reference to FIG. 2 will be described.

  FIG. 16 is a functional block diagram for explaining the configuration of receiving apparatus 2000 of the present embodiment.

  Referring to FIG. 16, 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. 17 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. 17 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. 17 also exemplarily shows the configuration of the reception unit 2100.3 in the 5 GHz band.

  Referring to FIG. 17, RF section 2400.3 of receiving section 2100.3 performs low-frequency amplifier 3010 for amplifying a 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.

  The baseband processing unit 2500.3 receives the signal from the ADC 3050, and performs a fast Fourier transform on the GI removal unit 4010 for removing the guard interval part and the signal from which the guard interval is removed. An FFT unit 4020 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 executed 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.

100 experimental apparatus 110 display apparatus 120 experimental system control apparatus 130 input / output operation apparatus 140 wireless transmission / reception apparatus 150 low noise amplifier (900 MHz / 2.4 GHz / 5 GHz compatible)
160 Bandpass filter (900MHz / 2.4GHz / 5GHz compatible)
170 Antenna (900MHz / 2.4GHz / 5GHz compatible)
1000 Transmitting apparatus 1010 S / P conversion unit 1020.1 to 1020.3 Radio frame generation unit 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 1072 Busy / idle duration acquisition unit 1074 Busy / idle duration categorization unit 1076 Duration prediction error probability acquisition unit 1078 Duration occurrence probability prediction unit 1080 Access control unit 1110 Error correction coding unit 1112 Interleaving unit 2000 Receiver 2010 .1 to 2010.3 Antenna 2020 Local oscillator 2100.1 to 2100.3 Reception unit 2400.1 to 2400.3 RF unit 2500.1 to 2500.3 Baseband processing unit 2600 Synchronization processing unit 2700 P / S Section 2800 digital signal processor 4040 error correcting unit 4042 deinterleaving section.

Claims (15)

A channel state prediction device for predicting a busy state and an idle state duration of a radio channel performing random access control in a target frequency band,
A channel usage monitoring unit that monitors the usage status of the radio channel at a plurality of measurement points in the frequency band;
A plurality of specific times are set for the plurality of measurement time points according to the observed use situation at the plurality of measurement time points observed, and categorization is performed in combination thereof, and a plurality of categorized measurement time points A channel state prediction apparatus comprising: a channel use state prediction unit that predicts a channel use state at the next time point and generates prediction information.   The channel usage status prediction unit predicts the channel usage status at the next time point and generates the prediction information by using the autoregressive model for the plurality of categorized measurement time points according to the observed usage status. The channel state prediction apparatus according to claim 1, wherein: The channel usage status prediction unit
A busy / idle duration acquisition unit for determining busy / idle state of the wireless channel and measuring a duration of the busy / idle state;
A busy / idle duration categorizing unit that categorizes busy / idle durations acquired by the busy / idle duration acquisition unit,
A duration prediction error probability acquisition unit that predicts a next busy / idle occurrence time from the acquired categorized busy / idle duration and calculates a probability of occurrence of a prediction error with respect to a measurement value by the channel usage state observation unit. When,
The channel state prediction apparatus according to claim 1, further comprising: a duration occurrence probability prediction unit that predicts the occurrence probability of the next busy / idle duration based on the occurrence probability of the prediction error. The first half busy / idle duration categorization section
4. The busy / idle duration is set for each of the busy / idle durations, and the obtained busy / idle durations are categorized by combining the set busy time range and the idle time range. Channel state prediction device. The duration prediction error probability acquisition unit is
The obtained busy / idle duration is categorized into the busy / idle duration to learn parameters of the prediction formula of the autoregressive model, and the next busy / idle occurrence time is predicted using the learned parameters. 5. The channel state prediction apparatus according to claim 4, wherein a probability of occurrence of a prediction error with respect to a measurement value by the channel usage state observation unit is calculated. A channel state prediction method for predicting a busy state and an idle state duration of a radio channel performing random access control in a target frequency band,
Observing the usage status of the radio channel in the frequency band at a plurality of measurement points;
A channel state prediction method comprising: predicting a channel use state at a next time point and generating prediction information according to the observed use state at the plurality of measurement points.   The step of predicting the channel usage situation at the next time point and generating the prediction information according to the observed usage situation at the plurality of measurement time points is categorized according to the observed usage situation. The channel state prediction method according to claim 6, wherein the prediction information is generated by predicting a channel use situation at a next time point by using an autoregressive model for a plurality of measurement points. A wireless communication device for transmitting a signal using a plurality of wireless channels performing random access control in each of a plurality of frequency bands separated from each other,
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 channel utilization state observing unit for observing the utilization state of the wireless channel at a plurality of measurement points in the plurality of frequency bands;
According to the observed usage status at the plurality of measurement points, a channel usage status prediction unit that predicts the channel usage status at the next time point and generates prediction information;
Based on the prediction information, the digital signal processing unit and the high-frequency processing unit are controlled, and the partial data is synchronized with the plurality of radio channels as packets for the plurality of frequency bands at the same timing. A wireless communication device comprising: an access control unit for transmission.   The channel usage status prediction unit generates the prediction information by predicting the channel usage status at the next time point by the autoregressive model for the plurality of categorized measurement points according to the observed usage status. The wireless communication apparatus according to claim 8, wherein: The channel usage status prediction unit
A busy / idle duration acquisition unit for determining busy / idle state of the wireless channel and measuring a duration of the busy / idle state;
A busy / idle duration categorizing unit configured to categorize busy / idle durations obtained by setting a plurality of specific times of busy / idle durations and the busy / idle durations acquiring unit,
A duration prediction error probability acquisition unit that predicts a next busy / idle occurrence time from the acquired categorized busy / idle duration and calculates a probability of occurrence of a prediction error with respect to a measurement value by the channel usage state observation unit. When,
The wireless communication device according to claim 9, further comprising: a duration occurrence probability prediction unit that predicts an occurrence probability of a next busy / idle duration based on the occurrence probability of the prediction error. The first half busy / idle duration categorization section
11. The busy / idle duration is set for each of the busy / idle durations, and the obtained busy / idle durations are categorized by combining the set busy time range and the idle time range. Wireless communication device. The duration prediction error probability acquisition unit is
The obtained busy / idle duration is categorized into the busy / idle duration to learn parameters of the prediction formula of the autoregressive model, and the next busy / idle occurrence time is predicted using the learned parameters. The radio communication apparatus according to claim 11, wherein a probability of occurrence of a prediction error with respect to a measurement value by the channel usage state observation unit is calculated.   The wireless communication apparatus according to claim 8 or 9, wherein the duration prediction error probability acquisition unit executes a process of updating the parameter of the prediction formula according to a traffic situation. A wireless communication method for transmitting a signal using a plurality of wireless channels performing random access control in each of a plurality of frequency bands separated from each other,
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;
Observing the use status of the radio channel in the plurality of frequency bands at a plurality of measurement points;
According to the observed usage status at the plurality of measurement points, predicting channel usage status at the next time point and generating prediction information;
And a step of transmitting each partial data as a packet for each of the plurality of frequency bands synchronously and at the same timing based on the prediction information using the plurality of wireless channels.   The step of predicting the channel usage situation at the next time point and generating the prediction information according to the observed usage situation at the plurality of measurement time points is categorized according to the observed usage situation. The wireless communication method according to claim 14, wherein the prediction information is generated by predicting a channel use situation at a next time point by using an autoregressive model for a plurality of measurement points.