JP2018170654A - Wireless communication apparatus and wireless communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless communication device capable of improving the utilization efficiency of a wireless channel while improving the transmission speed even when a hidden terminal or an interference source exists. A wireless communication device 1000 for performing wireless communication bundles and uses a plurality of basic wireless channels set within a predetermined frequency band. The plurality of basic radio channels includes a primary channel / sub-primary channel and a secondary channel for combining with these. The sub-primary channel selection unit 6800 determines the channel having the smallest number of hidden terminals among the basic wireless channels according to the detection result of the channel scan of the wireless communication device 1000 and the channel scan information from other wireless communication devices. To choose as. [Selection diagram] Figure 2

Description

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

  In a conventional wireless LAN system, communication is performed using a frequency band of 20 MHz per channel. In the IEEE 802.11n and later standards, a channel bonding function for performing communication by bundling a plurality of channels is defined (for example, Patent Document 1). According to the IEEE802.11n standard, communication can be performed using a 40 MHz frequency band by bundling up to two channels according to the channel usage status. In the IEEE802.11ac standard, communication can be performed using a frequency band of 160 MHz by bundling up to 8 channels.

  Here, FIG. 18 is a conceptual diagram showing a channel configuration of the IEEE 802.11ac standard.

  As shown in FIG. 18, the transmitting station sets a channel called “primary channel”, and sets other bundled channels as secondary channels.

  FIG. 18A shows an example in which 44 ch is a primary channel and 36, 40, 48, 52, 56, 60, and 64 ch are secondary channels. More specifically, it is an example of a secondary channel for 48 MHz for 40 MHz transmission, a secondary channel for 36 and 40 ch for 80 MHz transmission, and a secondary channel for 52 to 64 ch for 160 MHz transmission. Whether or not the secondary channel can be used is determined by whether or not the channel is being used by another transmitting station.

  Here, if only the primary channel (44ch) is unused, communication is performed using the 20 MHz frequency band. If the primary channel (44ch) and the secondary channel (48ch) are not used, communication is performed using a frequency band of 40 MHz by channel bonding. Similarly, if other secondary channels are unused, the primary channel and the secondary channel can be bundled and transmitted using a frequency band of 80 Hz or 160 MHz. If the primary channel is in use, the transmitting station cannot communicate.

  FIG. 18B shows an example in which 52ch is a primary channel and 36, 40, 44, 48, 56, 60, and 64ch are secondary channels. More specifically, 56ch is a secondary channel for 40 MHz transmission, 60 and 64ch are secondary channels for 80MHz transmission, and 36 to 48ch are secondary channels for 160MHz transmission. Also in this case, as in FIG. 18A, whether or not the secondary channel is available is determined by whether or not the channel is being used by another transmitting station.

  Such a channel bonding function is applied mainly to transmission of data frames, and management frames such as beacons and probes are transmitted using only the primary channel.

  That is, as shown in FIG. 18, channel bonding is a system in which the roles of channels are divided and a plurality of channels are used simultaneously.

  The “primary channel” here means a channel for exchanging control information for establishing data transmission and connection between the master unit and the slave unit, and “secondary channel”. ")" Means a channel that is used simultaneously to achieve a higher data transmission rate for data transmission in the primary channel.

  With such a configuration, transmission of user data and transmission of control information are performed on the primary channel, and transmission of user data on the primary channel is assisted on the secondary channel. As a result, the data transmission speed can be improved while maintaining compatibility with conventional communication. The same concept is used not only in channel bonding in the IEEE 802.11ac standard but also in carrier aggregation in LTE-A (Long Term Evolution-Advanced) described below, for example.

  That is, another 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), has a maximum bandwidth of 20 MHz. It is possible to communicate using it.

  Furthermore, in LTE-A, which is an advanced version of LTE, in order to realize further high-speed transmission while ensuring backward compatibility with LTE, a component carrier (CC: A carrier aggregation (CA) technique that uses a plurality of component carriers (Bundle Carriers) 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 2 and Patent Document 3).

  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.

  By the way, for example, in the setting of the primary / secondary channel in the IEEE802.11ac standard shown in FIG. 18, one primary channel having a 20 MHz bandwidth is determined in advance, for example, on the base station (access point) side. In addition, the position of the secondary channel is defined in advance so as to be uniquely determined by the position of the selected primary channel.

  As a result, carrier sensing is performed in the primary channel to acquire a transmission opportunity, and carrier sensing is performed in the secondary channel, and if it is in an idle (IDLE) state, higher speed transmission using the secondary channel can be performed.

  However, on the other hand, in such a configuration, there is a problem that the transmission opportunity is limited due to the availability of the primary channel.

  That is, when performing broadband transmission using the secondary channel, the wireless communication apparatus according to the IEEE802.11ac standard has a function of confirming the usage status of the primary and secondary channels. However, if the primary channel is busy, both the primary channel and the secondary channel are handled as busy.

  On the other hand, in order to transmit control information such as beacons on the primary channel, the concept of the primary channel is used in order to exchange control information while maintaining backward compatibility with devices that do not have a transmission function using the secondary channel. Is necessary.

  Therefore, conventionally, although there has been a technique for improving the transmission speed by bundling a plurality of radio channels at the same time, there has been a problem that the utilization efficiency of the radio channel is not necessarily high.

  In order to solve such problems, the concept of “sub-primary channel” is introduced to realize efficient use of radio resources, and “primary channel (primary channel)” is introduced. A method for obtaining a transmission opportunity when either “channel)” or “sub-primary channel” is available has been proposed (Non-Patent Document 1). In this method, it is important which channel is set as a sub-primary channel, and it has been proposed to use the following criteria.

  (S1) When the bandwidth of the basic radio channel is L, a sub-primary channel is selected so that the channel pattern that can select a combined channel that can secure a larger bandwidth in a higher layer is the largest. When there are a plurality of basic radio channels having the same number of channel patterns of the combined channels that can be selected, the better one of the signal to noise ratio (SNR) is selected.

  (S2) Among the selectable basic radio channels, a basic radio channel having a high probability of becoming an idle state (a basic channel having a low probability of becoming a busy state) is preferentially selected as a sub-primary channel.

JP 2016-21625 A specification JP 2011-111433 A JP 2013-187561 A

doc. IEEE 802.11-14 / 1437r1 (IEEE 802.11 standardization contribution)

  However, in an actual environment, the access point AP and the terminal STA exist at different positions. For this reason, the interference point is different between the access point AP and the terminal STA, and therefore, the usage status of the radio channel is different.

  In particular, when a hidden terminal to the terminal STA occurs when viewed from the access point AP, collision with a frame transmitted by the hidden terminal is likely to occur during frame transmission from the AP to the STA, and efficient transmission may not be performed. There is.

  The present invention has been made in order to solve the above-described problems. The purpose of the present invention is to perform transmission by bundling a plurality of radio channels at the same time even when there are hidden terminals and interference sources. To provide a wireless communication apparatus and a wireless communication method capable of improving the utilization efficiency of a wireless channel while improving the speed.

  According to one aspect of the present invention, a wireless communication apparatus for performing wireless communication using at least one of a plurality of wireless channels set within a predetermined frequency band, wherein the plurality of wireless channels Includes a plurality of basic radio channels arranged close to each other within a predetermined frequency band and a combined channel obtained by bundling adjacent basic radio channels, and the plurality of basic radio channels are transmitted to other radio communication devices. A combined channel is generated corresponding to a predetermined primary channel, sub-primary channel, and primary channel or sub-primary channel for transmitting control information and user data that are periodically transmitted to notify itself. Secondary channels for transmitting user data, and each of a plurality of basic wireless channels by other wireless communication devices Scanning information for collecting channel scan information relating to the usage status of each of a plurality of basic wireless channels from other wireless communication devices within the communicable range of the wireless communication device A collecting means, and a sub primary channel selecting means for selecting a sub primary channel among the basic radio channels according to the detection result and channel scan information of the channel scanning means. The hidden terminal and the interference source are specified based on the detection result and the channel scan information, and the basic radio channel that minimizes either the number of hidden terminals or the number of interference sources is determined as the sub-primary channel.

  Preferably, the apparatus further comprises channel selection means for selecting a combined channel for communication in accordance with the detection result of the channel scanning means, and the channel selection means i) when the primary channel is unused, the user data as the primary channel Select a channel to combine and transmit an unused secondary channel, and ii) if the primary channel is in use, select a channel to transmit user data by combining the sub-primary channel and an unused secondary channel select.

  Preferably, the sub primary channel selection means preferentially selects a channel with the smallest number of hidden terminals as a sub primary channel.

  Preferably, the sub primary channel selection means preferentially selects a channel with the smallest number of interfering terminals as a sub primary channel.

  Preferably, the channel scanning means includes a first high-frequency processing unit for use in primary channel communication and a second high-frequency processing unit for executing a channel scan for selecting a sub-primary channel.

  Preferably, the sub primary channel selection unit updates the sub primary channel in response to a predetermined condition being met.

  Preferably, the predetermined condition is that another wireless communication device newly enters or leaves the communicable range of the wireless communication device.

  Preferably, the predetermined condition is that the utilization rate of the basic radio channel being used is equal to or greater than a predetermined threshold value.

  Preferably, the predetermined condition is that a frame transmission failure probability is equal to or higher than a predetermined threshold.

  According to another aspect of the present invention, there is provided a wireless communication method for performing wireless communication using at least one of a plurality of wireless channels set within a predetermined frequency band, the plurality of wireless channels Includes a plurality of basic radio channels arranged close to each other within a predetermined frequency band and a combined channel obtained by bundling adjacent basic radio channels, and the plurality of basic radio channels are transmitted to other radio communication devices. A combined channel is generated corresponding to a predetermined primary channel, sub-primary channel, and primary channel or sub-primary channel for transmitting control information and user data that are periodically transmitted to notify itself. Each of a plurality of basic radio channels by other radio communication devices, including a secondary channel for transmitting user data Channel scan step for detecting the usage status, and scan information collection for collecting channel scan information related to the usage status of each of a plurality of basic radio channels from other radio communication devices within the communicable range of the radio communication device And a sub-primary channel selection step for selecting a sub-primary channel from among the basic radio channels according to the detection result of the channel scan step and the channel scan information. The sub-primary channel selection step includes: Based on the detection result and the channel scan information, the hidden terminal and the interference source are identified, and the basic radio channel that minimizes either the number of hidden terminals or the number of interference sources is determined as the sub-primary channel.

  According to the present invention, even when a hidden terminal or an interference source exists, it is possible to improve the use efficiency of the radio channel while improving the transmission speed by bundling a plurality of radio channels and using them simultaneously.

3 is a conceptual diagram showing a channel configuration according to Embodiment 1. FIG. It is a functional block diagram for demonstrating the structure of the principal part of the radio | wireless communication apparatus 100 of this Embodiment. It is a conceptual diagram which shows an example of the format of the flame | frame which the radio | wireless communication apparatus which concerns on this embodiment transmits or receives. It is a conceptual diagram for demonstrating the subject in the selection process of a sub primary channel in case a hidden terminal exists. It is a sequence diagram for demonstrating the selection process of a primary channel and a sub primary channel. It is a conceptual diagram which shows the channel scan result notified to terminal AP from access point AP, and the channel scan result of access point AP. 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. 6 is a conceptual diagram for explaining a configuration of a radio channel according to Embodiment 2. FIG. It is a functional block diagram for demonstrating the structure of the transmitter 1000 of this Embodiment. It is a functional block diagram for demonstrating the example of a more detailed structure of the transmitter 1000. FIG. It is a functional block diagram for demonstrating the structure of transmitter 1000 'which is another structure. It is a functional block diagram for demonstrating the example of a more detailed structure of transmitter 1000 '. It is a functional block diagram for demonstrating the structure of the receiver 2000 of embodiment. 3 is a functional block diagram for explaining an example of a more detailed configuration of receiving apparatus 2000. FIG. It is a functional block diagram for demonstrating the structure of receiver 2000 'which is another structure. It is a functional block diagram for demonstrating the example of a more detailed structure of receiver 2000 '. It is a conceptual diagram which shows the channel structure of the IEEE802.11ac standard.

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.
[Embodiment 1]
In the following, using the concept of “sub-primary channel” disclosed in Non-Patent Document 1 described above, even when a hidden terminal exists, a plurality of wireless channels are bundled and used simultaneously to improve the transmission rate. A wireless communication method that can improve the utilization efficiency of the wireless channel will be described.

  FIG. 1 is a conceptual diagram showing a channel configuration according to the first embodiment.

  In FIG. 1, the present embodiment is described as a modification to the IEEE802.11ac standard channel configuration. However, the present embodiment is not necessarily limited to such a channel configuration.

For example, if there are 2 ⁿ radio channels (basic radio channels) having a bandwidth of L (MHz) per radio channel (n is a natural number), by bundling these radio channels two by two, 2 ^n-1 adjacent higher-bandwidth combined channels are generated, and 4 ⁿ + 1 adjacent higher-bandwidth combined channels are generated, and finally, In other words, any channel configuration may be used as long as 2 ⁿ radio channels are bundled to generate one combined channel having a larger bandwidth.

  In FIG. 1, a channel called “Sub-Primary Channel” is introduced.

  That is, in FIG. 1, the “primary channel” is a channel for exchanging control information for establishing data transmission and connection between the parent device and the child device, as in the past.

  On the other hand, the “sub-primary channel” is a channel that performs data transmission in the same manner as the primary channel.

  The “secondary channel” is a channel that is used simultaneously to achieve a higher data transmission rate for data transmission in the primary channel and the sub-primary channel.

  Here, the “sub-primary channel” is a channel that only handles transmission of user data, but is positioned as a channel that shares data transmission of the primary channel. Therefore, also in the configuration of FIG. 1, for example, the beacon is transmitted only on the “primary channel”.

  More specifically, as control information for performing wireless communication, a certain wireless communication device is directed from one wireless communication device to another wireless communication device, such as a beacon from a wireless LAN access point. "First control information" that is transmitted at regular intervals to notify the presence of the data, "second control information" that is control information necessary for demodulation on the receiving side of the transmitted data, As will be described later, “third control information” collected via another wireless device to scan for the presence of a hidden terminal is included.

  For example, in a wireless LAN, beacon packets are generally transmitted every 100 milliseconds, and access point encryption setting, access point communication transmission rate setting, SSID (Service Set ID), ESSID (Extended Service Set ID). ) Is included.

  On the other hand, the second control information includes information that may be changed for each frame. For example, MCS (Modulation and Coding for notifying the reception side of a combination such as a modulation scheme and a coding rate) Scheme) information.

  In the present embodiment, the first control information is transmitted on the primary channel, and the second control information and the third control information are also transmitted on the sub-primary channel. Since the first control information is only transmitted at regular intervals as described above, the primary channel is not used for transmission of the first control information during the remaining time.

  As shown in FIG. 1, a plurality of sub-primary channels are set. Unlike the conventional case, it is determined that transmission is possible if not only the primary channel but also any of the sub-primary channels is free. In FIG. 1, as an example, there are a plurality of sub-primary channels, but there may be one.

  Here, in the channel configuration, where the sub-primary channel is set is assumed to be broadcast as control information such as a beacon from the parent device or the base station.

  Which channel is assigned as a secondary channel to a certain sub-primary channel can be the same as that shown in FIG.

That is, when one of 2 ⁿ (n is a natural number) radio channels (basic radio channels) is set as a primary channel and a plurality of sub-primary channels are set, the primary channel or each sub By bundling two primary channels, ^2n-1 adjacent radio channels that generate adjacent combined channels with higher bandwidths are assigned as secondary channels. The same applies to the case where a combined channel with a larger bandwidth is generated by bundling more basic radio channels.

Therefore, the combined channel for one primary channel and the combined channel for the other sub-primary channel become the same combined channel when the combination hierarchy becomes a certain level or higher. For example, in FIG. 1, when the primary channel of the basic radio channel is represented by vertical stripes and the sub-primary channel of the basic radio channel is represented by horizontal stripes, when the combination hierarchy becomes more than a certain level, This is represented by checkered stripes.
[Configuration of wireless communication device]
FIG. 2 is a functional block diagram for explaining the configuration of the main part of radio communication apparatus 100 of the present embodiment.

  Note that the wireless communication apparatus 100 indicates the configuration of both the access point AP and the terminal STA.

  In the configuration of the wireless communication apparatus 100 illustrated in FIG. 2, a configuration is described in which the empty channel search performs “virtual carrier sense” for the primary channel and the sub-primary channel.

  Here, “virtual carrier sense” is briefly summarized for explanation of terms. In the IEEE802.11 standard for wireless LAN, (1) collision avoidance by CSMA / CA, (2) hidden terminal avoidance by RTS (Request To Send), CTS (Clear To Send) exchange, (3) transmission waiting time by Duration Notification etc. are implemented.

  For example, first, terminal A having a frame to be transmitted to terminal B physically senses a channel (carrier) (measures received power). If the channel is idle, a backoff is performed. Thereafter, terminal A transmits an RTS frame to terminal B. Terminal B that has received the RTS transmits a CTS frame to terminal A. Thereafter, terminal A transmits a data frame, and terminal B returns an ACK frame. The RTS, CTS, and data frame include the time (Duration) that the channel will be occupied from now on. Duration is also called a NAV (Network Allocation Vector) period. Therefore, the terminal C or the terminal D that intercepted these frames suspends (suspends) transmission during the duration even if there is a frame to be transmitted. That is, the terminal C and the terminal D check whether they are in the NAV period prior to carrier sense before frame transmission. This is called “virtual carrier sense” and is distinguished from normal carrier sense (physical carrier sense).

  In other words, when virtual carrier sense is used, a node that does not receive radio waves directly from the transmitting node notifies all nodes that are within the communication range of the receiving node by notifying the receiving node that receives the signal of the transmitting node by CTS. The node can detect the communication of the transmitting node.

  Referring to FIG. 2, radio communication apparatus 100 includes a preamble detection unit for performing preamble detection on a primary channel based on a received signal from reception high-frequency processing unit (RF RX) unit 2400 for reception. 6100, and preamble detection units 6202.1 to 6202. for performing an empty channel search for the sub-primary channel. p.

  For the primary channel and the sub-primary channel, the data demodulator 2500, 6610.1-6610. By performing data demodulation using p, the empty state of the channel is detected by the virtual carrier sense described above.

  Here, it is assumed that p sub-primary channels are set.

  Further, the wireless communication device 100 detects the empty channel by detecting the received power with respect to the primary wireless channel and the basic wireless channel other than the primary channel based on the reception signal from the reception high frequency processing unit (RF RX) unit 2400 for reception. Received power detection units 6400.1 to 6400 for executing search. q is included. Here, it is assumed that there are q other channels.

  The signal from the preamble detector 6100 is demodulated by the data demodulator 2500 and passed to the process to the MAC layer as control information and user data.

  In addition, the data demodulator 2500, the data demodulator 6610.1-6610. The signal from p is also provided to sub primary channel selection section 6800. The sub-primary channel selection unit 6800 determines whether the transmission source of the signal is an interference source from the MAC address described in the received frame.

  As will be described later, the wireless communication device 100 collects information on the channel scan results from other wireless communication devices via the RF RX unit 2400, the preamble detection unit 6100, and the data demodulation unit 2500. The data is given to the sub primary channel selection unit 6800.

(Channel selection process)
First, if the primary channel is in an idle state as a result of the empty channel search and can be transmitted through this channel, the radio frame generated by the radio frame generation unit 1020 using the primary channel is transmitted to the transmission high-frequency processing unit. 1040.

  On the other hand, when there are a plurality of transmission candidate primary channels / sub-primary channels as a result of the empty channel search, the sub-primary channel selection unit 6800 out of them follows the “sub-primary channel selection method” described later. One basic radio channel is selected as the sub-primary channel.

  The transmission channel selection unit 6600 selects, based on the selected primary channel or sub-primary channel, as a transmission channel, for example, a combined channel in which basic radio channels that can secure the maximum bandwidth are bundled according to the current communication status or the like. To do.

  That is, transmission channel selection section 6600 selects a combined channel for communication as follows according to the channel scan result.

    i) When the primary channel is unused, the channel is selected so that user data is transmitted by combining the primary channel and the unused secondary channel.

    ii) When the primary channel is in use, the channel is selected so that the user data is transmitted by combining the sub-primary channel and the unused secondary channel.

  In this case, the radio frame generated by the radio frame generation unit 1020 using the combined channel set by the transmission channel selection unit 6600 is transmitted by the transmission high frequency processing unit 1040.

  2, the RF RX unit 2400, the preamble detection unit 6100, the received power detection units 62000.1 to 6200. p, received power detectors 6400.1-6400. q, the sub primary channel selection unit 6800, and the transmission channel selection unit 6600 are collectively referred to as a channel state detection unit 6000.

  FIG. 3 is a conceptual diagram illustrating an example of a format of a frame transmitted or received by the wireless communication apparatus according to the present embodiment.

  Referring to FIG. 3, a PHY frame (or PPDU: PHY Protocol Data Unit) has a preamble, a physical layer header, and a MAC frame (corresponding to a physical layer payload). The preamble is a known signal used for establishing timing and frequency synchronization, estimating a transmission path, and the like.

  The physical layer header mainly includes information necessary for decoding the MAC frame, and includes information such as a frame length, a modulation scheme, and a coding scheme, for example. These pieces of information are also used for determining whether the medium is empty or not based on physical carrier sense. That is, in physical carrier sense, the data rate is calculated from the modulation scheme and coding scheme, and from this and the frame length, it can be determined that the channel is blocked during the duration of the frame.

  A MAC frame (or MPDU: MAC Protocol Data Unit) has a MAC layer header, a MAC layer payload, and an FCS (Frame Chack Sequence). The FCS is added as a value for checking data consistency.

  Preamble detection units 6100, 6, 202.1 to 6202. p detects whether the preamble is detected and the contents of the physical layer header, and the sub-primary channel selection unit 6800 detects whether the channel is free or blocked. In “channel scan” to be described later, preamble detection units 6202.1 to 6202. p sequentially changes the frequency of the channel to be scanned.

  On the other hand, the data demodulator 2500, 6610.1-6610. In the demodulated signal from p, the sub-primary channel selection unit 6800 can detect the presence of the interference source based on the destination address and the source address described in the Mac layer header.

(Channel selection process)
FIG. 4 is a conceptual diagram for explaining a problem in the sub-primary channel selection process when a hidden terminal exists.

  Referring to FIG. 4, in an actual environment, access point AP and terminals STA1 and STA2 exist at different positions. For this reason, the interference source is different between the AP and the STA, and therefore the usage status of the radio channel is different.

  In particular, when a hidden terminal (access point AP2 in FIG. 4) occurs at the terminal STA1 when viewed from the access point AP1, a collision with a frame transmitted by the hidden terminal occurs when performing frame transmission from the access point AP1 to the terminal STA1. It is likely to occur and there is a risk that efficient transmission cannot be performed. Therefore, it is desirable to avoid using a channel where many hidden terminals are generated as a sub-primary channel.

  Therefore, it is not sufficient for the base unit / base station to select the sub-primary channel based only on the result collected by its own carrier sense. That is, it is difficult for the access point AP1 to know the existence of a hidden terminal (access point AP2 in FIG. 4) unless other wireless devices (terminal STA1 in FIG. 4) are notified of the presence.

  First, if the primary channel is in an idle state as a result of the empty channel search and can be transmitted through this channel, the radio frame generated by the radio frame generation unit 1020 using the primary channel is transmitted to the transmission high-frequency processing unit. 1040.

  On the other hand, when there are a plurality of transmission candidate primary channels / sub-primary channels as a result of the empty channel search, the sub-primary channel selection unit 6800 has the following “sub-primary channel selection scheme” among them. In this way, one basic radio channel is selected.

  In the following, “BSS (Basic Service Set)” means a network composed of one AP and subordinate wireless LAN client terminals within the reach of the radio waves of the AP in the wireless LAN infrastructure mode. It shall be said.

  i) Collect information on channel utilization status from a plurality of wireless devices, and perform sub-primary channel selection control based on the results.

  In the sub-primary channel selection control, the following indices are considered.

ii) Prioritize the channel with the smallest number of hidden terminals as seen from the BSS ib) Prioritize the channel with the smallest number of interfering terminals as seen from the BSS ii) RF different from the RF unit used for communication of the primary channel By performing a channel scan for acquiring information necessary for sub-primary channel selection control, the sub-primary channel selection control is performed while maintaining a communication link on the primary channel.

  iii) Update the sub-primary channel in response to changes in channel usage.

  The criteria for determining whether or not to update the sub-primary channel are as follows.

    iii-a) STA entry or withdrawal from the BSS occurred.

    iii-b) The (temporal) utilization rate of the channel in use is greater than or equal to a predetermined threshold.

    iii-c) The frame transmission failure probability (the probability that the reception completion response ACK is not returned) is equal to or greater than the threshold value.

  FIG. 5 is a sequence diagram for explaining a primary channel and sub-primary channel selection process.

  In FIG. 5, it is assumed that the access point AP selects a sub primary channel. Initially, it is assumed that both the access point AP and the terminal STA are in a dormant state.

  Referring to FIG. 5, first, when the access point AP is activated (S100), the access point AP performs an initial channel scan (S102), and the sub primary channel selection unit 6800 of the access point AP selects the sub primary channel. Determine (S104).

  Here, since the terminal STA has not yet been activated, the sub-primary channel that minimizes the number of interfering terminals observed by the access point AP can be selected. In addition, since it does not communicate if there is no terminal STA1, it can also be set as the structure which does not set a sub primary channel until terminal STA joins.

  Subsequently, when the terminal STA is activated (S106), the terminal STA notifies the access point AP of the capability of the terminal STA via the primary channel. Here, the capability of the terminal STA is, for example, information such as the number of RF units included in the terminal STA (the number of channels capable of virtual carrier sensing simultaneously).

  In response, the access point AP notifies the terminal STA of the sub primary channel set in step S104.

  Subsequently, the access point AP determines the necessity of updating the sub primary channel (S108).

  When the sub-primary channel update process is required, the access point AP requests the terminal STA to provide information.

  The criteria for determining whether update processing is necessary are as described in iii-a) to iii-c) above.

  Then, a channel scan is executed at the access point AP and the terminal STA (S110a, S110b).

  When the channel scan is completed, the terminal STA notifies the access point AP of the channel scan result.

  The channel scan result is information on a list of hidden terminals and interference sources of the scanned channel.

  The access point AP determines the sub-primary channel according to the result of its own channel scan and the result of the channel scan from the terminal STA (S112), and notifies the determined sub-primary channel to the terminal STA.

  Thereafter, the processing after S108 is executed periodically or every time the events iii-a) to iii-c) serving as determination criteria occur.

  FIG. 6 is a conceptual diagram showing the channel scan result notified from the terminal STA to the access point AP and the channel scan result of the access point AP.

  In FIG. 6, access points AP or terminals STA connected by a line indicate that they are within a communication (interference) range.

  In the channel scan at the access point AP itself, “interference source 1” and “interference source 3” are found.

  In the channel scan at the terminal STA, “interference source 2” and “interference source 3” are found.

  As a result, the sub-primary channel selection unit 6800 of the access point AP can detect that the number of hidden terminals is 2 and the number of interference source terminals is 3 in communication with the terminal STA.

  This will be described in more detail as follows.

  (1) Each wireless device (AP, STA) scans each basic wireless channel, receives a frame of another BSS coming in, and extracts the MAC address of the wireless device (other BSS) that becomes an interference source. An interference source list is created for each channel from the result.

  (2) The wireless device (access point AP in FIG. 5) that selects the sub-primary channel belongs to an interference source list of each basic wireless channel to another wireless device (in FIG. 5, for example, a BSS managed by itself). From the terminal STA).

  (3) The sub-primary channel selection unit 6800 of the access point AP determines that a wireless device corresponding to any of the following in each basic wireless channel is a hidden terminal, and counts the number thereof.

i) Radio apparatus not included in the interference source list of the AP but included in the interference source list of the terminal STA (interference source 2 in the example of FIG. 6)
ii) Radio apparatus that is included in the interference source list of the AP but not included in the interference source list of the terminal STA (interference source 1 in the example of FIG. 6)
In addition, the sub primary channel selection unit 6800 of the access point AP also counts the number of interfering terminals (the number of non-overlapping interference sources).

  (4) The sub-primary channel selection unit 6800 of the access point AP selects a predetermined number of sub-primary channels in order from the basic radio channel with a small number of radio devices determined to be hidden terminals.

  When the number of hidden terminals is the same, the sub-primary channel selection unit 6800 of the access point AP “in order of decreasing channel number”, “in order of decreasing busy probability”, and “in order of decreasing number of radio apparatuses serving as interference sources” The sub-primary channel is selected based on a predetermined criterion. The busy probability can be estimated from, for example, a history of channel sense results for the corresponding channel so far.

  Conversely, the number of interfering terminals may be selected with priority instead of the number of hidden terminals. The number of interfering terminals is an index indicating the total amount of interference flying into its BSS.

  (5) The access point AP notifies the terminal STA of the selected sub primary channel.

  (6) The sub-primary channel selection unit 6800 of the access point AP determines whether or not to update the sub-primary channel as necessary, and returns to (1) if the update is necessary.

  Here, as an example in the case of updating, there are the following cases as described above.

a) When a terminal STA enters or leaves the BSS (because an interference source to be considered may change)
b) The (temporal) utilization rate of the channel in use is greater than or equal to the threshold (because the channel is congested and using a different sub-primary channel may allow more communication. )
c) Frame transmission failure probability (probability that ACK does not return) is more than a threshold value (Propagation fluctuations and many collisions may occur, and more communication can be performed using another sub-primary channel) Because there is a possibility of becoming.)
By configuring as described above, even if the primary channel is busy, it is possible to bundle a plurality of basic radio channels and realize higher speed transmission, while improving the transmission speed, It is possible to improve the utilization efficiency of the radio channel.
[Embodiment 2]
Hereinafter, as a receiving apparatus according to the second embodiment, a plurality of existing license-free bands (for example, a 920 MHz band used for IoT and the like, a 2.4 GHz band used for a wireless LAN, and the like as described above) In the 5 GHz band, an embodiment will be described by way of example of a transmission device 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.

  FIG. 7 is a conceptual diagram for explaining the configuration of the wireless communication system of the present embodiment.

  Referring to FIG. 7, 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 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. 8 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. 8, the number of symbols proportional to the transmission rate Ri of each band using the transmission data series is divided 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.

  FIG. 9 is a conceptual diagram for explaining a configuration of a radio channel according to the second embodiment.

  Referring to FIG. 9, in a wireless communication system capable of performing cognitive wireless communication by sharing a frequency with an existing system in a plurality of existing unlicensed bands largely separated from each other as described in FIG. 8. As described in the first embodiment, the transmission using the sub-primary channel is performed.

  That is, for example, as shown in FIG. 9A, in the 2.4 GHz band, one primary channel and one sub-primary channel are set. Further, as shown in FIG. 9B, in the 5 GHz band, one primary channel is set, and in addition, three sub-primary channels are set.

By adopting such a configuration, it is possible to handle each frequency band in the same manner as one frequency band in the first embodiment in communication using a plurality of existing license-free bands that are largely separated from each other. Become.
[Configuration of transmitter]
FIG. 10 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 according to the present embodiment.

  Referring to FIG. 10, transmitting apparatus 1000 includes a serial / parallel conversion (hereinafter referred to as S / P conversion) unit 1010 for performing processing for assigning a transmission sequence to each frequency band as described in FIG. For the data after P conversion, a radio frame (packet) for communication by a predetermined radio communication method such as addition of a physical header, addition of an error correction code, interleave processing, etc. is formed for each frequency band. Digital frame conversion unit 1020.1 to 1020.3 for executing digital processing and digital analog conversion processing and predetermined modulation method for digital signals from radio frame generation units 1020.1 to 1020.3, respectively Modulation processing (for example, orthogonal modulation processing for a predetermined multilevel modulation system), up-conversion processing, power amplification processing, etc. Including frequency processing unit and the (RF unit) from 1040.1 to 1040.3, and an antenna 1050.1 to 1050.3 for delivering respectively a high frequency signal RF unit 1040.1 to 1040.3. 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, channel usage status monitoring section 1060 is similar to channel status detection section 6000 of the first embodiment, and channel status detection sections 6000.1 to 6000.3 for performing carrier sense in the corresponding frequency bands. including. For example, the channel state detection unit 6000.1 is in charge of the 920 MHz band, the channel state detection unit 6000.2 is in charge of the 2.4 GHz band, and the channel state detection unit 6000.3 is in charge of the 5 GHz band.

  As described with reference to FIG. 7, 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 performs error correction encoding for error correction encoding section 1110 and error correction code. An interleaving / mapping unit 1120 for executing interleaving processing and mapping processing on the output of the converting unit 1110, an IFFT unit 1130 for executing inverse Fourier transform processing, and a GI adding unit for adding a guard interval part 1140 and a digital-to-analog converter (DAC) 1150 for converting the digital signal into analog signals of I component and 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.
[Other configuration of transmitting device]
10 and 11, the example of the configuration of the transmission apparatus 1000 has been described.

  10 and 11, the transmission data is distributed to each frequency band by the S / P converter 1010, and then the error correction coding process and the interleave process are performed.

  However, the configuration of the transmission apparatus 1000 is not limited to such a case.

  FIG. 12 is a functional block diagram for explaining the configuration of the transmission apparatus 1000 ′ having such another configuration.

  The transmission apparatus 1000 ′ in FIG. 12 has a configuration in which transmission data is subjected to error correction encoding processing and interleaving processing and then distributed to each frequency band by the S / P conversion unit 1010. The radio frame generation units 1020.1 to 1020.3 perform mapping processing, IFFT processing, addition of guard intervals, and digital / analog conversion processing.

  FIG. 13 is a functional block diagram for explaining an example of a more detailed configuration of such a transmission apparatus 1000 ′.

  The functional block diagram shown in FIG. 13 also shows the configuration of a transmission apparatus that conforms to a wireless communication scheme similar to the wireless communication standard 802.11a as an example.

As shown in FIG. 13, after error correction coding processing by the error correction coding processing unit 1110 and interleaving processing by the interleaving unit 1112, the S / P conversion unit 1010 distributes the frequency bands to each frequency band. The frequency diversity effect can be obtained more powerfully.
[Receiver configuration]
Below, the structure of the receiver used in the radio | wireless communications system which was demonstrated in FIG. 8 is demonstrated.

  FIG. 14 is a functional block diagram for explaining a configuration of receiving apparatus 2000 according to the embodiment.

  Referring to FIG. 14, 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. 15 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. 15 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 apparatus corresponds to the configuration of the transmitting apparatus shown in FIG.

  FIG. 15 also exemplarily shows the configuration of the reception unit 2100.3 in the 5 GHz band.

  Referring to FIG. 15, RF section 2400.3 of receiving section 2100.3 performs low-frequency amplifier 3010 for amplifying the reception 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. 15 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 fast Fourier transform, a demapping / deinterleaving unit 4030 for executing demapping and deinterleaving processing on the output of the FFT unit 4020, and an error correction unit 4040 are included.

  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.
[Other configuration of receiving apparatus]
14 and 15, an example of the configuration of the receiving device 2000 has been described.

  In the configurations of FIGS. 14 and 15, the S / P conversion unit is performed after the demapping / deinterleave processing and error correction processing are performed on the received data, corresponding to the configuration of the transmission side of FIGS. 10 and 11. 1010 is a configuration for combining signals from each frequency band.

  However, the configuration of receiving apparatus 2000 is not limited to such a case.

  FIG. 16 is a functional block diagram for explaining the configuration of the receiving apparatus 2000 ′ having such another configuration.

The receiving apparatus 2000 ′ in FIG. 16 is configured to perform deinterleaving processing and error correction processing on the received data after combining the signals of the respective frequency bands by the P / S conversion unit 2700. Baseband processing units 2500.1 to 2500.3 perform guard interval removal, FFT processing, and demapping processing.

  Therefore, the receiving device 2000 ′ in FIG. 16 corresponds to reception of a signal from the transmitting device 1000 ′ in FIG.

  FIG. 17 is a functional block diagram for explaining an example of a more detailed configuration of such a receiving apparatus 2000 ′. The configuration in FIG. 17 also corresponds to the configuration in FIG.

  The functional block diagram shown in FIG. 17 also shows the configuration of a transmission device according to the same wireless communication system as the wireless communication standard 802.11a as an example.

  As shown in FIG. 17, for each frequency band, after the guard interval removal by the guard interval removal unit 4010, the FFT processing by the FFT unit 4020, and the demapping processing by the demapping unit 4032, each frequency is converted by the P / S conversion unit 2070. Combine the band signals. After combining by the P / S conversion unit 2070, deinterleaving processing by the deinterleaving unit 4042 and error correction processing by the error correction unit 4040 are executed.

  With the configuration as described above, each transmission data can be mapped to a plurality of frequency bands, and data transmission can be performed by adjusting the transmission timing.

  In the configuration of the present embodiment, even when the primary channel is busy, a plurality of basic wireless channels can be bundled to achieve higher-speed transmission, and the wireless channel can be improved while improving the transmission speed. It is possible to improve the utilization efficiency.

  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 Transmitter, 1010 S / P converter, 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 Observation unit, 1070 channel utilization status prediction unit, 1080 access control unit, 2000 receiver, 2011-2010.3 antenna, 2020 local oscillator, 2100.1-2100.3 receiver, 2400.1-2400.3 RF Unit, 2500.1 to 2500.3 baseband processing unit, 2600 synchronization processing unit, 2700 P / S conversion unit, 2800 digital signal processing unit, 6000 channel status detection unit, 6100, 6202.1 to 6202. p Preamble detector, 6400.1-6400. q reception power detection unit, 6600 transmission channel selection unit, 6800 sub-primary channel selection unit.

Claims (10)

A wireless communication device for performing wireless communication using at least one of a plurality of wireless channels set within a predetermined frequency band,
The plurality of radio channels include a plurality of basic radio channels arranged close to each other in the predetermined frequency band, and a combined channel in which the basic radio channels adjacent to each other are bundled.
The plurality of basic wireless channels include a predetermined primary channel for transmitting control information and user data periodically transmitted to notify another wireless communication device itself, a sub-primary channel, and the primary channel Or a secondary channel for generating the combined channel and transmitting user data, corresponding to each of the sub-primary channels,
Channel scanning means for detecting the usage status of each of the plurality of basic wireless channels by another wireless communication device;
Scan information collecting means for collecting channel scan information on the usage status of each of the plurality of basic radio channels from other radio communication devices within the communicable range of the radio communication device;
Sub-primary channel selection means for selecting a sub-primary channel among the basic radio channels according to the detection result of the channel scan means and the channel scan information, the sub-primary channel selection means,
A wireless terminal that identifies a hidden terminal and an interference source based on a detection result of the channel scanning means and the channel scan information, and determines a basic wireless channel that minimizes either the number of hidden terminals or the number of interference sources as a sub-primary channel. Communication device. Channel selection means for selecting the combined channel for communication according to the detection result of the channel scanning means, the channel selection means,
i) If the primary channel is unused, select a channel to transmit user data by combining the primary channel and an unused secondary channel;
The radio communication apparatus according to claim 1, wherein when the primary channel is in use, the channel is selected so that user data is transmitted by combining the sub-primary channel and an unused secondary channel.   The radio communication apparatus according to claim 1, wherein the sub primary channel selection unit preferentially selects a channel with the smallest number of hidden terminals as a sub primary channel.   The radio communication apparatus according to claim 1 or 2, wherein the sub-primary channel selection unit preferentially selects a channel having the smallest number of interfering terminals as a sub-primary channel. The channel scanning means includes
A first high frequency processing unit for use in communication of the primary channel;
The radio | wireless communication apparatus of any one of Claims 1-4 containing the 2nd high frequency process part for performing the channel scan for selection of the said sub primary channel.   The radio communication apparatus according to claim 1, wherein the sub primary channel selection unit updates the sub primary channel in response to a predetermined condition being met.   The wireless communication device according to claim 6, wherein the predetermined condition is that another wireless communication device newly enters or leaves the communicable range of the wireless communication device.   The wireless communication apparatus according to claim 6, wherein the predetermined condition is that a utilization rate of the basic wireless channel being used is equal to or greater than a predetermined threshold value.   The wireless communication apparatus according to claim 6, wherein the predetermined condition is that a frame transmission failure probability is equal to or higher than a predetermined threshold value. A wireless communication method for performing wireless communication using at least one of a plurality of wireless channels set within a predetermined frequency band,
The plurality of radio channels include a plurality of basic radio channels arranged close to each other in the predetermined frequency band, and a combined channel in which the basic radio channels adjacent to each other are bundled.
The plurality of basic wireless channels include a predetermined primary channel for transmitting control information and user data periodically transmitted to notify another wireless communication device itself, a sub-primary channel, and the primary channel Or a secondary channel for generating the combined channel and transmitting user data, corresponding to each of the sub-primary channels,
A channel scanning step for detecting the usage of each of the plurality of basic wireless channels by another wireless communication device;
A scan information collecting step for collecting channel scan information related to the usage status of each of the plurality of basic radio channels from another radio communication device within the communicable range of the radio communication device;
A sub-primary channel selection step for selecting a sub-primary channel among the basic radio channels according to the detection result of the channel scan step and the channel scan information,
In the sub-primary channel selection step, a hidden terminal and an interference source are identified based on the detection result of the channel scan step and the channel scan information, and a basic radio channel that minimizes either the number of hidden terminals or the number of interference sources is selected. A wireless communication method for determining as a sub-primary channel.