JP6652468B2 - Wireless communication device and wireless communication method - Google Patents

Description

  Embodiments described herein relate generally to a wireless communication device and a wireless communication method.

  A wireless communication system that performs communication between an access point and a wireless communication terminal (hereinafter, referred to as a terminal) is known. For example, a wireless LAN (Local Area Network) adopting CSMA / CA (Carrier Sense Multiple Access / Collision Aidance) is widely known. In the wireless LAN, there is frequency multiplex communication in which transmission to a plurality of terminals or reception from a plurality of terminals is performed simultaneously using different frequency components for each terminal as communication resources. Here, the frequency component is defined as a resource unit including one or a plurality of subcarriers, and orthogonal frequency division for simultaneously transmitting to a plurality of terminals or receiving from a plurality of terminals using the resource unit as a communication resource. A multiple access method (OFDMA; Orthogonal Frequency Division Multiple Access) is considered. Simultaneous transmission from an access point to a plurality of terminals corresponds to downlink OFDMA (DL-OFDMA) transmission, and simultaneous transmission from a plurality of terminals to the access point corresponds to uplink OFDMA (UL-OFDMA) transmission.

  In such OFDMA, frames of different frame types may be simultaneously transmitted and received for each terminal. When such different types of frames are assigned to different resource units, the frame transmission time may differ for each resource unit. For example, a control frame such as a Block ACK frame and a data frame have greatly different frame lengths. Since the timing at which frame transmission / reception can be started after the execution of OFDMA depends on the longest frame length in OFDMA, the efficiency decreases in resource units in which frames with a short frame length are transmitted / received in OFDMA. Such a problem may also occur in other multiplex communication systems, for example, a multi-user MIMO (Multi-Input Multi-Output).

IEEE Std 802.11ac (TM) -2013 IEEE Std 802.11 (TM) -2012 IEEE 802.11-15 / 0132r7 IEEE802.11-15 / 841r1 IEEE802.11-15 / 831r2

  An embodiment of the present invention aims to improve communication efficiency when performing multiplex communication with a plurality of terminals.

  A wireless communication device as an embodiment of the present invention includes a receiving unit that receives a plurality of multiplexed first frames and a transmitting unit that multiplexes a second frame and a third frame. The second frame includes a delivery acknowledgment indicating whether or not at least two of the plurality of first frames have been successfully received.

FIG. 1 is a diagram showing a wireless communication system according to a first embodiment. FIG. 4 is a diagram for explaining allocation of resource units. FIG. 4 is a diagram for explaining allocation of resource units. The figure which shows the example of a basic format of a MAC frame. The figure which shows the example of a format of an information element. FIG. 4 is a diagram showing an example of an operation sequence according to the first embodiment. FIG. 3 is a diagram for explaining a schematic configuration of a physical header. FIG. 4 is a view showing a format example of a trigger frame according to the first embodiment. FIG. 6 is a view showing another example of the format of the trigger frame according to the first embodiment. FIG. 6 is a diagram showing still another format example of the trigger frame according to the first embodiment. FIG. 2 is a diagram illustrating a schematic format example of a physical packet used in DL-OFDMA transmission. FIG. 6 is a diagram showing another example of the operation sequence according to the first embodiment. FIG. 4 is a diagram illustrating a flowchart of an example of an operation related to scheduling of an access point according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 3 is an explanatory diagram of a Multi-STA BA frame. FIG. 6 is a diagram illustrating a flowchart of another example of the operation related to the scheduling of the access point according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 9 is a view showing still another example of the operation sequence according to the first embodiment. FIG. 2 is a functional block diagram of a wireless communication device mounted on the access point according to the first embodiment. FIG. 2 is a functional block diagram of the wireless communication device mounted on the terminal according to the first embodiment. FIG. 4 is a diagram showing a flowchart of an operation of the access point according to the first embodiment. FIG. 5 is a diagram showing a flowchart of an operation of the terminal according to the first embodiment. The figure which shows the example which transmits DL-OFDMA of several types of frames. FIG. 13 is a diagram illustrating a flowchart of an example of an operation related to scheduling of an access point according to the second embodiment. FIG. 13 is a diagram illustrating a flowchart of another example of the operation related to the scheduling of the access point according to the second embodiment. FIG. 33 is an exemplary view for explaining a specific example of the operation in FIG. 32; The figure which shows the example of a whole structure of a terminal or an access point. FIG. 13 is a diagram illustrating a hardware configuration example of a wireless communication device mounted on an access point or a wireless terminal according to a third embodiment. FIG. 13 is an exemplary perspective view of a wireless terminal according to a fourth embodiment; FIG. 14 is a diagram showing a memory card according to a fourth embodiment. The figure which shows an example of the frame exchange of a contention period. The functional block diagram of access point 400 concerning a 14th embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. IEEE Std 802.11 ^™ -2012 and IEEE Std 802.11ac ^™ -2013, which are known as wireless LAN standards, and a specification framework document (Specification) for IEEE Std 802.11ax, which is a next-generation wireless LAN standard. Framework Document), IEEE 802.11-15 / 0132r7, dated July 20, 2015, is incorporated by reference herein in its entirety.

(First embodiment)
FIG. 1 is a configuration diagram of a wireless communication system including an access point (AP), which is a base station according to the first embodiment, and a wireless communication terminal (hereinafter, a terminal). The wireless communication system is based on the IEEE 802.11 standard, but a system based on another communication system is also possible. An access point has basically the same function as a terminal except that it has a relay function and the like, and thus it can be said that an access point is also one form of a terminal. Each of the access point and the terminal includes a wireless communication device that performs communication conforming to the IEEE 802.11 standard. The wireless communication device mounted on the terminal communicates with the wireless communication device mounted on the access point. The wireless communication device mounted on the access point communicates with the wireless communication device mounted on the terminal.

  Terminals (STAs: STAs) 1 to 8 are connected to an access point (AP: Access Point) 11 to form one wireless communication system or a wireless communication group (BSS: Basic Service Set). The connection means a state in which a wireless link has been established, and a wireless link is established by completing the exchange of parameters necessary for communication through an association process with an access point. The terminals 1 to 8 belong to the BSS of the access point 11.

  The access point 11 has at least one antenna. Here, the access point 11 includes a plurality of antennas. The wireless communication device of the access point 11 transmits and receives a MAC frame (hereinafter, sometimes referred to as a frame) to and from a plurality of terminals via these antennas. The wireless communication device includes a wireless communication unit (Transceiver) connected to an antenna for transmitting and receiving frames, and a control unit for controlling communication with a terminal. The wireless communication unit (Transceiver) is formed by, for example, an RF (Radio Frequency) integrated circuit, and the control unit is formed by, for example, a baseband integrated circuit. However, the configuration is not limited to this.

  Each terminal 1 to 8 includes one or a plurality of antennas. Each terminal is equipped with a wireless communication device (see FIG. 27 described later). The wireless communication device of each terminal transmits and receives frames to and from an access point via an antenna. The wireless communication device of each terminal includes a wireless communication unit (Transceiver) connected to an antenna for transmitting and receiving frames, and a control unit for controlling communication with the access point 11. The wireless communication unit (Transceiver) is formed by, for example, an RF (Radio Frequency) integrated circuit, and the control unit is formed by, for example, a baseband integrated circuit. However, the configuration is not limited to this.

  The access point 11 forms a BSS or a wireless network (referred to as a first network) with each terminal. Alternatively, the access point 11 may be separately connected to another network (called a second network) that is wired, wireless, or a hybrid thereof. The access point 11 may relay communication between the first network and the second network. Further, the access point 11 may relay communication between a plurality of terminals in the first network. A frame such as a data frame generated by each of the terminals 1 to 8 is transmitted to the access point 11. The access point 11 transmits the data frame to another terminal in the first network or the second network according to the destination address. Note that the frame described in this specification is not limited to, for example, a frame called in the IEEE 802.11 standard, but may be a packet called a packet.

  In the present embodiment, it is assumed that OFDMA (Orthogonal Frequency Division Multiple Access) communication is performed between the access point 11 and a plurality of terminals 1 to 8 or a plurality of terminals selected from these. In OFDMA, a resource unit including one or a plurality of subcarriers (which may be called a subchannel, a resource block, a frequency block, or the like) is allocated to a terminal as a communication resource, and communication is performed simultaneously with the plurality of terminals on a resource unit basis. The uplink OFDMA is described as UL-OFDMA, and the downlink OFDMA is described as DL-OFDM.

  The resource unit is a frequency component that is a minimum unit of a resource for communication. FIG. 2 shows resource units (RU # 1, RU # 2,... RU # K) secured in a continuous frequency domain of one channel (here, described as channel M). A plurality of subcarriers orthogonal to each other are arranged in the channel M, and a plurality of resource units including one or a plurality of continuous subcarriers are defined in the channel M. One or more subcarriers (guard subcarriers) may be arranged between resource units, but guard subcarriers are not essential. Each subcarrier in the channel may be assigned a number for identifying the subcarrier. The bandwidth of one channel is, for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, or the like, but is not limited thereto. A plurality of channels of 20 MHz may be combined into one channel. The number of subcarriers or the number of resource units in a channel may be different depending on the bandwidth. By using different resource units simultaneously by a plurality of terminals, OFDMA communication is realized.

  The bandwidth (or the number of subcarriers) of the resource unit may be common to each resource unit, or the bandwidth (or the number of subcarriers) may be different for each resource unit. FIG. 3 schematically shows an example of an arrangement pattern of resource units in one channel. The horizontal direction along the paper surface corresponds to the frequency domain direction. FIG. 3A shows an example in which a plurality of resource units (RU # 1, RU # 2,... RU # K) having the same bandwidth are arranged. FIG. 3B shows an example in which a plurality of resource units (RU # 11-1, RU # 11-2,..., RU # 11-L) having a larger bandwidth than FIG. . FIG. 3C shows an example in which resource units of three types of bandwidths are arranged. The resource units (RU # 12-1 and RU # 12-2) have the largest bandwidth, and the resource unit RU # 12- (L-1) has the same bandwidth and resource unit (RU) as in FIG. # K-1, RU # K) have the same bandwidth as in FIG.

  Note that the number of resource units used by each terminal in OFDMA is not limited to a specific value, and one or more resource units may be used. When the terminal uses a plurality of resource units, a plurality of frequency-continuous resource units may be bonded and used as one resource unit, or a plurality of resource units at distant locations may be used. Is also good. The resource unit # 11-1 in FIG. 3B is an example of a resource unit obtained by bonding the resource units # 1 and # 2 in FIG. 3A. The identifier (# 11-1) is assigned to the bonded resource unit.

  A resource unit may be defined from a plurality of subcarriers arranged discontinuously. The number of channels used in the OFDMA communication is not limited to one, and another channel (see channel N in FIG. 2) arranged in a frequency domain away from channel M also has the same resources as channel M. Units may be reserved and resource units in both channel M and channel N may be used. The allocation method of the resource units in the channel M and the channel N may be the same or different. The bandwidth of one channel is, for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, or the like as described above, but is not limited thereto. It is also possible to use more than two channels. Note that the channel M and the channel N can be considered together as one channel.

  Note that a terminal that implements OFDMA has at least a channel having a basic channel width (a 20 MHz channel width if a terminal compatible with the IEEE 802.11a / b / g / n / ac standard is a legacy terminal) in a legacy terminal to be backward-compatible. Thus, a physical packet including a frame can be received and decoded (including demodulation and decoding of an error correction code). Carrier sensing is performed in units of the basic channel width. The carrier sense includes physical carrier sense (Physical Carrier Sense) related to busy / idle of CCA (Clear Channel Assessment) and virtual carrier sense (Virtual Carrier) based on a medium reservation time described in a received frame. Sense). As in the latter case, a mechanism for virtually determining that a medium is busy, or a period in which a medium is virtually busy, is called a NAV (Network Allocation Vector). The carrier sense information based on CCA or NAV performed on a channel basis may be commonly applied to all resource units in the channel. For example, all resource units belonging to a channel whose carrier sense information indicates idle are idle.

  In addition to the above-described resource unit-based OFDMA, OFDMA can be a channel-based OFDMA. The OFDMA in this case may be particularly called an MU-MC (Multi-User Multi-Channel). In the MU-MC, an access point allocates a plurality of channels (one channel width is, for example, 20 MHz) to a plurality of terminals, and simultaneously transmits to a plurality of terminals or simultaneously receives from a plurality of terminals by using the plurality of channels simultaneously. Do. In the OFDMA described below, a resource unit-based OFDMA is assumed, but an embodiment of a channel-based OFDMA can be realized by performing necessary replacement such as replacing a resource unit described below with a channel.

  FIG. 4A shows a basic format example of a MAC frame. The data frame, management frame, and control frame according to the present embodiment (the details of each frame type will be described in an embodiment described later) are based on such a frame format. This frame format includes a MAC header (MAC header), a frame body (Frame body), and FCS fields. 4B, the MAC header includes fields of Frame Control, Duration / ID, Address1, Address2, Address3, Sequence Control, QoS Control, and HT (High Throughput) control.

  Not all of these fields need to be present, and some fields may not be present depending on the type of frame. For example, the Address 3 field may not exist. In some cases, both or one of the QoS Control and HT Control fields may not be present. In some cases, the frame body field does not exist. On the other hand, other fields not shown in FIG. 4 may exist. For example, an Address 4 field may further be present.

  The Address 1 field contains a destination address (Receiver Address; RA), the Address 2 field contains a source address (Transmitter Address; TA), and the Address 3 field contains a BSS identifier according to the use of the frame. A BSSID (Basic Service Set IDentifier) (in some cases, a wildcard BSSID for all BSSs by putting 1 in all bits) or a TA is entered.

  As described above, the Frame Control field includes two fields such as a type (Type) and a subtype (Subtype). Data frames, management frames, and control frames are roughly classified in the Type field, and the detailed classification of the roughly classified frames, such as a BA frame, a BAR frame, and a Beacon frame in the management frame, is performed. This is performed in the Subtype field. Trigger frames to be described later may also be distinguished by combinations of types and subtypes.

  The Duration / ID field describes the medium reservation time, and when a MAC frame addressed to another terminal is received, the medium is virtually busy from the end of the physical packet including the MAC frame to the medium reservation time. Is determined. Such a mechanism for virtually determining that the medium is busy, or a period in which the medium is virtually busy, is referred to as a NAV (Network Allocation Vector), as described above. The QoS field is used for performing QoS control for performing transmission in consideration of the priority of the frame. The HT Control field is a field introduced in IEEE 802.11n.

  In the management frame, an information element (Information element; IE) to which a unique Element ID (IDentifier) is assigned is set in the Frame Body field. One or more information elements can be set in the frame body field. As shown in FIG. 5, the information element has an Element ID field, a Length field, and an information (Information) field. An information element is identified by an Element ID. The information field stores the content of the information to be notified, and the Length field stores the length information of the information field.

  In the FCS field, FCS (Frame Check Sequence) information is set as a checksum code used for detecting a frame error on the receiving side. Examples of the FCS information include a CRC (Cyclic Redundancy Code).

  FIG. 6 shows a typical operation sequence example of the access point 11 according to the present embodiment and the terminals 1 to 8. Before the start of this operation sequence, communication (single-user communication) is individually performed between the access point and some or all of the terminals 1 to 8 on a CSMA / CA basis. In single-user communication, for example, communication is performed between an access point and a terminal using one channel having a basic channel width (for example, 20 MHz). As an example of single-user communication, when data for uplink transmission is held in a terminal, the terminal acquires an access right to a wireless medium according to CSMA / CA. For this reason, the terminal performs carrier sense for the carrier sense time (standby time) between the DIFS / AIFS [AC] time and the randomly determined back-off time, and when the medium (CCA) is determined to be idle, For example, an access right for transmitting one frame is acquired. The terminal transmits a data frame including the data to be transmitted (more specifically, a physical packet including the data frame), and when the access point receives the data frame normally, after a SIFS time from the completion of the reception of the data frame, the terminal confirms the delivery. An ACK frame as a response frame (more specifically, a physical packet including the ACK frame) is returned. The terminal determines that the data frame has been successfully transmitted by receiving the ACK frame. The data frame transmitted to the access point may be an aggregation frame (such as A-MPDU (medium access control (MAC) protocol data unit)), and in this case, the delivery acknowledgment frame to which the access point responds is a BA (Block Ack) frame. Good (same below). Note that DIFS / AIFS [AC] means one of DIFS and AIFS [AC]. In the case of not supporting QoS, it indicates DIFS, and in the case of supporting QoS, it indicates AIFS [AC] determined according to an access category (AC: Access Category) of data to be transmitted.

  Here, the access point determines the start of the OFDMA sequence (UL-OFDMA and DL-OFDMA) at an arbitrary timing. The OFDMA sequence means that communication including UL-OFDMA and DL-OFDMA is performed within a certain period determined by the access point. In this example, it is assumed that OFDMA is performed on the same channel as that for single-user communication (one channel having a basic channel width of 20 MHz). That is, it is assumed that OFDMA is performed using a plurality of resource units defined in a channel having a basic channel width of 20 MHz. However, it is also possible to perform OFDMA with other channel widths such as 40 MHz and 80 MHz. It is also possible to perform OFDMA for each channel by using a plurality of 20 MHz channels simultaneously. In each UL-OFDMA and DL-OFDMA performed in the OFDMA sequence, the arrangement and allocation of resource units do not need to be the same.

  Assume that the access point first decides to perform UL-OFDMA as an OFDMA sequence. In this case, the access point determines necessary items for UL-OFDMA and generates the trigger frame 501. The access point transmits the trigger frame 501 (more specifically, a physical packet including the trigger frame) based on the access right acquired according to CSMA / CA. The trigger frame 501 is transmitted on a channel having the same basic channel width as that of the single user communication. The physical packet including the trigger frame is obtained by adding a physical header to the head of the trigger frame, for example. As an example, as shown in FIG. 7, the physical header is an L-STF (Legacy-Short Training Field), an L-LTF (Legacy-Long Training Field), and an L-SIG (Legacy Signal) defined in the IEEE 802.11 standard. Field). L-STF, L-LTF, and L-SIG are fields that can be recognized by a terminal of a legacy standard such as IEEE802.11a. Is stored. Fields other than those described here (for example, fields that cannot be recognized by legacy terminals and can be recognized by OFDMA-compatible terminals) may be included. The trigger frame 501 may be a frame that can be received and decoded by legacy terminals in addition to UL-OFDMA compatible terminals. Note that “...” In FIG. 7 means that fields other than those shown in the figure may or may not be present.

  The access point 11 selects, for example, a terminal that performs UL-OFDMA as a determination of matters necessary for UL-OFDMA required for generating the trigger frame 501. As a selection method, for example, the presence / absence of a request for UL-OFDMA transmission may be collected from each terminal in advance, and the terminal may be selected from the terminal having a request. Alternatively, a terminal having the largest data amount may be preferentially selected or a terminal having the same data amount may be selected based on the transmission data amount in each terminal.

  When the access point manages the terminals in groups, all or some terminals belonging to the same group may be selected, or a group may be selected. In this case, the access point groups the terminal groups belonging to its own station in the association process or at any timing thereafter, and assigns each terminal identification information of each group (a group ID of IEEE802.11ac, or It is assumed that grouping information indicating a terminal ID belonging to each group and a list of terminal groups belonging to each group is notified by a management frame or the like. A list for all groups may be sent to each terminal, or only a list of groups to which the terminal belongs may be sent. As a criterion for selecting a group, items such as the presence or absence of a UL-OFDMA transmission request and the amount of transmission data for each terminal belonging to each group may be considered.

  Alternatively, a terminal or a group may be selected by round robin, or a terminal or a group may be selected at random.

  Alternatively, select a terminal having data that is estimated to be the same or close to the size of data to be transmitted next, or a terminal that has the same or close data generation cycle (a terminal whose generation cycle falls within a certain value) , Or a predetermined number of terminals having the closest occurrence cycle).

  Alternatively, terminals having the same data type of data to be transmitted may be selected. If the data type is QoS-compliant, the data type may be an AC (Access Category). Further, the data type may be TID (Traffic ID: traffic type).

  In addition, when the lower limit of the number of terminals to be selected is set, the number of terminals equal to or more than the lower limit may be selected. The example of selecting a terminal described here is merely an example, and a terminal may be selected by a method other than the method described here.

  Further, the access point determines at least one resource unit to be used by the selected terminal in UL-OFDMA. Furthermore, the access point may determine the maximum packet length (PPDU (Physical Protocol Data Unit) length) transmitted by the terminal in common or individually. For example, when the information including the TXOP length and / or the data amount necessary for the next transmission or both of them is acquired from each terminal, the TXOP length or the data amount (PPDU length or the like) notified from each terminal is used. Thus, the PPDU length may be determined. When the packet length is determined in common for each terminal, for example, the PPDU length may be determined based on the TXOP or the longest data amount among the terminals. Items other than those described here may be determined. For example, at least one of an error correction coding system, MCS (Modulation and Coding Scheme) that defines a transmission rate of PHY or MAC, or both of them may be determined. Specifically, the MCS for each terminal may be determined so that the PPDU length of each terminal is equal or close. If the MCS can be specified not only for the frame but also for the physical header (preamble), the MCS applied to the physical header may be determined. Also, the transmission power of each terminal may be determined. For example, the transmission power such that the reception power (such as RSSI) received from each terminal falls within the same or a certain range may be determined by measurement.

  The access point generates a trigger frame 501 upon determining items necessary for implementing UL-OFDMA communication, such as a terminal performing UL-OFDMA and a resource unit to be allocated to the terminal. The trigger frame 501 includes information (notification information) that needs to be notified to a terminal when performing UL-OFDMA transmission.

  FIG. 8 shows a format example of the trigger frame. The trigger frame 501 is defined based on the general MAC frame format shown in FIG. The header or frame body field of the trigger frame includes a common field (COMMOM Info.) And at least terminal information (STA Info.) Fields corresponding to the number of terminals that perform UL-OFDMA.

  The type of the Frame Control field may be a value representing the control frame, and the value of the subtype may be a value newly defined for the trigger frame. However, a configuration in which the frame type of the trigger frame is not a control frame but a management frame or a data frame is not excluded. Information necessary for the role of the trigger frame 501 (information of the common field and the terminal information field) may be added as an information element to the frame body field of the existing management frame. The value of the existing standard may be used as the value of the subtype.

  The RA (reception destination address) of the trigger frame 501 may be, for example, a broadcast address or a multicast address, and the address may be set in the address 1 field. As the TA (source address), the MAC address or BSSID of the access point may be set in the address 2 field.

  In the sequence example of FIG. 6, since five terminals 1 to 5 are selected as the frame body field of the trigger frame, five terminal information fields (STA info fields) 1 to 5 are set. In each terminal information field, information to be individually notified to the terminal is set. In the common field, information to be commonly notified to the terminals 1 to 5 selected as targets of UL-OFDMA is set.

  As an example of information to be set in the common field, for example, information on the number of terminal information fields is set. Since the number of terminal information fields can fluctuate according to the number of selected terminals, it is conceivable to set the number of terminal information fields in the common field. If the number of terminal information fields is fixed, the information is unnecessary.

  Further, information on the transmission timing of UL-OFDMA may be set in the trigger frame. If it is determined that uplink transmission is to be performed after a predetermined time (IFS of a predetermined value) from completion of reception of the trigger frame, since this time is known at each terminal, No settings are required.

  When the packet length or the time length for uplink transmission is common in each terminal, information specifying the packet length and / or the time length may be set in the common field.

  When a group of terminals is selected as a terminal to be subjected to UL-OFDMA, information (group ID) for identifying the group may be set in the common field. At this time, if there is a rule that all the terminals belonging to the group are the terminals for which UL-OFDMA is permitted, each terminal sets its own information in any of a plurality of terminal information fields. The setting of the terminal identifier in each terminal information field may be omitted as long as it is possible to recognize whether or not the terminal identifier is set. For example, if the access point has previously notified which terminal information field the terminal has been assigned to which terminal information field from the beginning or end, the setting of the terminal identifier may be omitted. Alternatively, when the position of the terminal information field is uniquely determined according to the position of the own terminal in the list of terminals in the group, the setting of the terminal identifier may be omitted.

  The terminal information fields 1 to n include, for example, a field for setting a terminal identifier (STA ID field) and a field for setting information for specifying a resource unit (RU # field). In addition, various fields that individually notify the terminal may be included. The identifier of each terminal is set in the STA ID field. The identifier of the terminal may be an association ID (AID) of the terminal, a MAC address, or another unique ID of the terminal. The association ID is an identifier assigned at the time of an association process performed between the terminal and the access point because the terminal belongs to the BSS of the access point.

  In the RU # field, information for specifying a resource unit used by the corresponding terminal in UL-OFDMA is set. The format of the information specifying the resource unit may be any format as long as the resource unit can be specified. For example, it may be specified by the number (identifier) of the resource unit. The number of the resource unit from the high frequency side or the low frequency side may be specified. A resource unit may be specified in combination with a channel identifier used in UL-OFDMA. Note that a configuration is also conceivable in which an identifier for identifying a set of a plurality of resource units is separately defined, and one or more identifiers of the set are specified in the RU # field. In this case, the terminal can grasp the available resource units from the identifier of the set.

  As another parameter example, information on at least one of a packet length (such as a PPDU length) that is allowed to be transmitted, an error correction coding scheme, and an MCS that defines a PHY and / or a MAC or both transmission rates may be set. . The unit of the packet length may be the data size or the time length (the occupation time length in space). When the packet length is common to the terminals, the information on the packet length may be set in the common field by omitting the setting in the terminal information field. Note that the maximum value of the packet length may be determined in advance by a standard or a system, and in this case, the packet length may be set within a range equal to or less than the maximum value. Instead of the packet length, it is also possible to use a MAC frame length or a medium access control (MAC) service data unit (MSDU) length. Further, as another parameter example, information of a data type to be transmitted by each terminal may be specified. As the data type, an access category (AC) or traffic information (TID: Traffic ID) may be set. The specified data type may be different for each terminal, or may be common for each terminal. Also, a plurality of data types may be specified. Information for designating the transmission power of each terminal may be set. When the UL-OFDMA transmission timing is individually specified for each terminal (when the UL-OFDMA transmission timing is adjusted for each terminal), information regarding the transmission timing may be set. For example, an adjustment amount for a predetermined transmission timing may be set as the information.

  In the example of FIG. 8, an example in which the common field and the terminal information field are set in the header or the frame body field has been described. However, part or all of the information set in the common field and the terminal information field is as shown in FIG. 9. Alternatively, it may be placed in the physical header. The physical header in FIG. 9 includes a common field and a terminal information field for the number of terminals after L-STF (Legacy-Short Training Field), L-LTF (Legacy-Long Training Field), and L-SIG (Legacy Signal Field). Including. When all the information to be notified is set in the physical header, the common information field and the terminal information field may be omitted from the MAC frame.

  As shown in FIG. 10, there may be a trigger frame configuration in which the common field is omitted. When the number of terminal information fields is fixed and all necessary information in the terminal information field is individually notified, the common field may be omitted.

  The trigger frame 501 transmitted from the access point is received by the terminals 1 to 8. When the terminals 1 to 8 decode the trigger frame 501 and determine that the reception has succeeded by the FCS check (CRC check or the like), the terminals 1 to 8 check whether the own terminal is designated in any of the terminal information fields 1 to n. This can be determined, for example, by checking whether the identifier of the own terminal is set in the STA ID fields of the terminal information fields 1 to n. Only when the group ID to which the own terminal belongs is set in the common field, the STA ID field of the terminal information field may be checked. Alternatively, if there is a rule that the own terminal is always specified when the group ID to which the own terminal belongs is set, it may be determined that the own terminal is specified. Alternatively, when the identifier of each terminal is set in the common field as information for specifying a terminal to be subjected to UL-OFDMA, it is determined whether the own terminal has been designated based on the common field. Is also good. The determination can be made by a method other than the method described here.

  A terminal specified as a target of UL-OFDMA specifies a resource unit used by the terminal itself. For example, the resource unit to be used is specified from the information set in the RU # field of the terminal information field.

  In this example, the terminals 1 to 8 receive the trigger frame 501, the terminals 1 to 5 determine that their own terminals are specified, and the terminals 6 to 8 determine that their own terminals are not specified. Terminals 1 to 5 generate data frames 511, 512, 513, 514, and 515 (more specifically, packets including the data frame) including data for uplink transmission, and generate a resource unit designated by the own terminal. To send to the access point. When parameters such as transmission power, MCS, and packet length are specified, a data frame is generated and transmitted according to the parameters. For example, terminal 1 specifies resource unit # 1, terminal 2 specifies resource unit # 2, terminal 3 specifies resource unit # 3, terminal 4 specifies resource unit # 4, and terminal 5 specifies resource unit # 5. Here, it is assumed that each of the data frames 511 to 515 is an aggregation frame in which a plurality of data frames are aggregated. However, each of the data frames 511 to 515 may be a single data frame (even if it is not an aggregation frame).

  The transmission of each data frame is performed after a time T1 (not shown) from the completion of reception of the trigger frame 501 by the terminals 1 to 5, and these data frames are simultaneously received by the access point. Thereby, UL-OFDMA transmission is performed. As the time T1, for example, a predefined IFS time [μs] can be used. The predefined IFS time may be a SIFS time (= 16 μs), which is a time interval between frames defined by the MAC protocol specification of IEEE 802.11 wireless LAN, or may be a larger or smaller value. The value of the time T1 is stored in the common information field and / or the terminal information field, and the terminals 1 to 5 may acquire the value of the time T1 from the common information field and / or the terminal information field. Alternatively, the time T1 may be notified in advance by another method such as a beacon frame or another management frame.

  When the access point notifies the adjustment amount of the transmission timing of the terminals 1 to 5 in the terminal information field or the common field of the trigger frame, the terminals 1 to 5 adjust the transmission timing by the notified adjustment amount, A data frame may be transmitted.

  The data frames 511, 512, 513, 514, and 515 transmitted by the terminals 1 to 5 may be frames having different contents or frames having the same contents. As a general expression, when a plurality of terminals transmit or receive an Xth frame or an access point expresses receiving or transmitting a plurality of Xth frames, the contents of these Xth frames are the same. May also be different.

  If the terminal does not have data to be transmitted on the uplink, the terminal has a frame of a predetermined format, for example, a frame having a physical header but no data field, or a physical header and a MAC header. However, a frame having no frame body field may be transmitted. Alternatively, the terminal may not perform any transmission operation. When the access point receives such a frame or receives no such frame, the terminal may determine that there is no data to be transmitted.

  When the access point 11 receives data frames transmitted from a plurality of terminals through UL-OFDMA transmission, the access point 11 checks a cyclic redundancy code (CRC) of each received data frame. Here, since it is assumed that the data frame is an aggregation frame, the CRC of a plurality of data frames is checked for each terminal. From the CRC check, it is determined whether each of the plurality of data frames in the aggregation frame transmitted by each terminal has been correctly received. The access point 11 generates a Block Ack frame (BA frame) as a delivery acknowledgment frame including a plurality of inspection results for each terminal based on the inspection result for each terminal 1 to 5 for each terminal. As shown in FIG. 6, the access point 11 aggregates one or more data frames including data addressed to each of the terminals 1 to 5 and an acknowledgment frame 521 that aggregates acknowledgment frames addressed to each of the terminals 1 to 5, 522, 523, 524, and 525 are generated for each terminal. The access point 11 transmits the aggregations 521 to 525 of each terminal in the same resource unit as that used by each terminal at the time of UL-OFDMA transmission, after a fixed time (such as SIFS time) from the completion of the reception of the data frames 511 to 515. (Ie, DL-OFDMA transmission). More specifically, a physical header is added to each of these aggregation frames and transmitted. The identifier of the resource unit to be received may be specified for each terminal in a predetermined field (herein, referred to as a SIG1 field) of the physical header.

  FIG. 11 shows a configuration example of a physical packet at the time of DL-OFDMA transmission of the aggregation frames 521 to 525. For example, the L-STF, L-LTF, and L-SIG fields described in FIG. 7 are transmitted with a channel width of 20 MHz, and the same value (bit string) is set in any of the aggregations 521 to 525. In the SIG1 field, information for associating a terminal identifier with a resource unit number (identifier) is set in order to specify a resource unit to be used for each terminal. The identifier of the terminal may be an association ID (AID), a part of the AID (Partial AID), or another identifier such as a MAC address. The SIG1 field is also transmitted with a channel width of 20 MHz, and the same value (bit string) is set in any of the aggregations 521 to 525. Each of the terminals 1 to 5 (and the other terminals 6 to 8) can decode the SIG1 field. The SIG2 field may be set for each resource unit, and information such as MCS necessary for decoding the data field may be set. Therefore, each terminal that has received the signal from the access point 11 can know the resource unit to be decoded by decoding the SIG1 field. It is also possible to define an ID that designates all or a specific group of terminals (for convenience, referred to as a broadcast ID or a multicast ID), and set information that associates the broadcast ID or the multicast ID with a resource unit. It is.

  The terminals 1 to 5 receive the aggregation frames 521 to 525 by decoding the signals of the specified resource units, respectively. The terminals 1 to 5 decode the data frames in the aggregation frames 521 to 525 and perform a CRC check, decode the BA frames in the aggregation frames 521 to 525, and execute the decoding of the data frames 511 to 515 transmitted by the own terminal. Determine success. Thereafter, the terminals 1 to 5 generate a delivery acknowledgment frame (BA frame or the like) for the data frame received from the access point, and after a certain time (SIFS time or the like) from the completion of the reception of the aggregation frames 521 to 525, the terminal 1 to 5 The acknowledgment frame may be transmitted (UL-OFDMA transmission). Alternatively, the terminals 1 to 5 may transmit (UL-OFDMA transmission) an aggregation frame in which other frames are aggregated in the acknowledgment frame in the same resource unit specified by DL-OFDMA. Thereafter, similarly, DL-OFDMA and UL-OFDMA may be continuously and repeatedly performed. The duration of the OFDMA sequence may be notified by a trigger frame 501 as an example. For example, the OFDMA sequence may be continued with the medium reservation period specified by the Duration / ID field of the trigger frame 501 as TXOP (Transmission Opportunity), or information about the period may be notified to each terminal in a common field. .

  In the sequence of FIG. 6, the access point may not have data addressed to terminals 1 to 5 at the time of DL-OFDM transmission. For example, the access point may have data addressed to terminal 1 but not have data addressed to terminals 2-5. In this case, the aggregation frame 521 may be transmitted to the terminal 1 and only the BA frame may be transmitted to the terminals 2 to 5. FIG. 12 shows a sequence example in this case. In this case, the resource units for the terminals 2 to 5 do not perform frame communication during the time from the completion of the transmission of the BA frame to the end of the aggregation frame 521 transmitted by the resource unit for the terminal 1, resulting in inefficient operation. is there. In this case, at the end of the BA frame transmitted by the resource units for the terminals 2 to 5, the other terminals are notified that the resource unit is busy during the time until the end of the aggregation frame 521. Therefore, padding data is added. However, it is also possible not to add padding data. The hatching in the figure indicates padding data (the same applies hereinafter).

  Therefore, the access point according to the present embodiment effectively performs DL-OFDMA scheduling (which resource unit is assigned which frame to which terminal) in order to increase the efficiency of DL-OFDMA transmission. It has one of the features.

  FIG. 13 shows a flowchart relating to DL-OFDMA scheduling of the access point according to the present embodiment. The timing at which this operation is performed may be arbitrarily determined, but may be, for example, when the transmission of the trigger frame 501 is completed, or when the reception of a frame transmitted by UL-OFDMA is completed.

  The access point transmits a frame other than the acknowledgment response frame (hereinafter, referred to as a transmission frame) to the terminal specified by the trigger frame 501 or the terminal that has transmitted UL-OFDMA (hereinafter, referred to as a target terminal). It is determined for each target terminal whether it exists (S101). As an example, the access point may determine whether a transmission frame to be transmitted to the target terminal exists based on whether data addressed to the target terminal exists in the buffer. The transmission frame may be a frame to be newly transmitted, or may be a retransmission frame of a frame that failed in the previous transmission. The frame type may be a data frame or a management frame. Here, a data frame is assumed.

  If there is no transmission frame for all of the target terminals, it is determined that each of the target terminals transmits a delivery confirmation response frame (BA frame or the like) using the resource unit used for UL-OFDMA transmission (S103). Then, the access point performs DL-OFDMA transmission of these acknowledgment frames after a fixed time (SIFS time or the like) after completion of reception of the data frames 511 to 515 transmitted by UL-OFDMA (S107). FIG. 14 shows a sequence example in this case. The access point transmits the BA frames 541, 542, 543, 544, and 545 to the terminals 1 to 5 by DL-OFDMA.

  Alternatively, in step S103, it may be determined that a frame including all the delivery acknowledgments of these target terminals (called a Multi-STA BA frame) is to be transmitted in a channel width band (here, a 20 MHz channel width band). Good. After a certain time (SIFS time or the like) from the completion of the reception of the data frames 511 to 515 transmitted by the UL-OFDMA, a Multi-STA BA frame is transmitted in the channel width band (S107). FIG. 15 shows a sequence example in this case. The access point 11 transmits a Multi-STA BA frame 551 to the terminals 1 to 5 in a band of a channel width. The destination address of the Multi-STA BA frame is, for example, a broadcast address or a multicast address. As a modified example, the MAC address of one of the terminals specified by the trigger frame 501 may be set. The Multi-STA BA frame is a frame in which the BA frame is diverted to notify the delivery confirmation response to a plurality of terminals, and details thereof will be described later.

  If the access point determines in step S102 that a transmission frame exists for at least one target terminal, the access point determines whether there is one or more target terminals for which no transmission frame exists (S104). When there is one target terminal having no transmission frame (that is, when there are a plurality of target terminals having a transmission frame), for the target terminal having a transmission frame, a transmission acknowledgment frame (such as a BA frame) is transmitted. It decides to transmit an aggregation frame that aggregates the frames with each resource unit, and for one target terminal having no transmission frame, sends an acknowledgment response frame (such as a BA frame) in the resource unit for the terminal. It is determined to transmit (S106). When the number of target terminals having no transmission frame is one, it is not possible to efficiently combine the delivery acknowledgments for a plurality of terminals into one frame, and thus such a determination is made. The access point performs DL-OFDMA transmission according to the determination after a fixed time (SIFS time or the like) from the completion of reception of the data frames 511 to 515 transmitted by UL-OFDMA (S107). FIG. 16 shows a sequence example in this case. The access point transmits the aggregation frames 561, 562, 563, and 564 to the terminals 1 to 4 and the BA frame 565 to the terminal 5 (DL-OFDMA transmission). Note that padding data is added to the end of the BA frame 565.

  If it is determined in step S104 that there are a plurality of target terminals having no transmission frame, the access point determines, for the target terminals having no transmission frame, a frame including a delivery acknowledgment response of these target terminals (Multi-STA BA (S105), and for the target terminal having the transmission frame, it is determined to transmit an aggregation frame in which the transmission frame and the acknowledgment response frame are aggregated (S105). Further, the resource unit for transmitting the Multi-STA BA frame and the resource unit for transmitting the aggregation frame are determined (S105). Since the Multi-STA BA frame is allocated to one resource unit, and the delivery acknowledgments for a plurality of terminals are combined into one Multi-STA BA frame, a free space is created in the resource unit. Therefore, at least one of the aggregation frames is generated. First, the aggregation frame may be assigned to a resource unit obtained by bonding two or more resource units. The access point performs DL-OFDMA transmission according to the determination after a fixed time (SIFS time or the like) from the completion of reception of the data frames 511 to 515 transmitted by UL-OFDMA (S107). FIG. 17 shows a sequence example in this case. The access point transmits the aggregation frames 571 and 572 to the terminals 1 and 2 using the resource units used by the terminals 1 and 2 for UL-OFDMA transmission, and transmits the Multi-STA BA frame 573 including the delivery acknowledgments of the terminals 3 and 4. In the UL-OFDMA transmission, the resource unit used by the terminal 3 is transmitted, and the aggregation frame 575 is transmitted to the terminal 5 and the resource units in which the two resource units used by the terminals 4 and 5 in the UL-OFDMA transmission are bonded. . Note that the identifier of the bonded resource unit may be the identifier of the resource unit after the bonding, or may be expressed by the identifier of the two resource units before bonding and the information indicating the bonding. . Padding data is added to the end of the Multi-STA BA frame 573, and the frame length is adjusted to the end of another frame. Since the terminal 5 can use more communication resources than the terminals 1 and 2, it can transmit data of a larger size. Thereby, the efficiency of DL-OFDMA can be improved.

  Here, the Multi-STA BA frame will be described. The Multi-STA BA frame is obtained by diverting a Block Ack frame (BA frame) in order to notify delivery acknowledgments to a plurality of terminals in one frame. When reusing a BA frame, the frame type may be control and the frame subtype may be BlockAck, as in a normal BA frame. FIG. 18A shows a format example of a Multi-STA BA frame when a BA frame is reused. FIG. 18B shows an example of a format of a BA Control field in a BA frame, and FIG. 18C shows an example of a format of a BA Information field in a BA frame. When reusing the BA frame, the BA Control field may indicate that the BA frame format has been extended to notify the delivery acknowledgment regarding a plurality of terminals. For example, in the IEEE 802.11 standard, the case where the Multi-TID subfield is 1 and the Compressed Bitmap subfield is 0 is the current reservation (Reserved). This may be used to indicate that it is an extended BA frame format for notifying delivery acknowledgments for a plurality of terminals. Alternatively, in FIG. 18 (B), the area of bits B3 to B8 is a reserved subfield, but a part or all of this area is in a BA frame format extended to notify delivery acknowledgments for a plurality of terminals. May be defined to indicate something. Alternatively, such notification need not be explicitly performed.

  The RA field in the BA frame may be a broadcast address or a multicast address. Alternatively, a unicast address of one of the terminals specified in the trigger frame may be used. The number of users (the number of terminals) reporting in the BA Information field may be set in the Multi-User subfield of the BA Control field. In the BA Information field, for each user (terminal), a subfield for setting an association ID (Association ID: AID) (described as Per TID Info in FIG. 18C) and a Block Ack start sequence control (Block Ack Starting) A Sequence Control subfield and a Block Ack Bitmap subfield are arranged.

  In the association ID (Per TID Info) subfield, an AID is set for user identification. The Block Ack start sequence control subfield and the Block Ack bitmap subfield may be omitted when the frame transmitted by the terminal is a single data frame (when it is not an aggregation frame). When the frame transmitted by the terminal is an aggregation frame, the sequence number of the first MSDU (medium access control (MAC) service data unit) of the delivery acknowledgment indicated by the BlockAck frame is stored in the Block Ack start sequence control subfield. I do. In the Block Ack bitmap subfield, a bitmap (Block Ack bitmap) including bits indicating whether or not each of the sequence numbers after the Block Ack start sequence number has been successfully received may be inserted.

  The terminal that has received the Multi-STA BA frame confirms the Type and the Subtype in the frame control field. When these are detected as control and BlockAck, the RA field is checked next, and since this value is a broadcast address or the like, each data frame in the frame transmitted by the terminal itself (here, an aggregation frame) is checked. The information of the delivery acknowledgment (success / non-success) is specified from the Block Ack Bitmap field, and whether the transmission of each data frame is successful is determined. For example, the TID Info subfield storing the AID of the own terminal is specified from within the BA Information field, and the value set in the Block Ack Starting Sequence Control subfield following the specified TID Info subfield (start sequence number) ) Is specified, and whether or not each sequence number after the start sequence number has been successfully transmitted is specified from the Block Ack bitmap. The bit length of the AID may be shorter than the length of the TID Info subfield, and the AID is, for example, in a partial area of the TID Info subfield (for example, 11 bits (B0-B10) from the top of 2 octets (16 bits)). It may be stored.

  When a plurality of terminals use a BA frame when transmitting a single data frame instead of an aggregation frame in UL-OFDMA, for example, the following may be performed. One bit in the TID Info subfield of each BA information field (for example, of the two octets (16 bits), the twelfth bit from the beginning (B11 if the beginning is B0)) is a bit (ACK) indicating whether it is ACK or BA. / BA bit), and a value indicating ACK is set in the bit. When a value indicating ACK is set, the Block Ack Starting Sequence Control subfield and the Block Ack Bitmap subfield are omitted. Thereby, ACKs of a plurality of terminals can be notified by one BA frame. When a plurality of terminals transmit aggregation frames as described above, a value indicating BA may be set in the ACK / BA bit. Thereby, even when a plurality of terminals transmit an aggregation frame or a single data frame, a delivery confirmation response can be sent to the plurality of terminals using the BA frame.

  In addition, as an example of processing on the terminal side after transmitting a data frame by a certain resource unit, the terminal waits for reception of a signal from the access point, and determines whether there is AID and resource unit information of the own terminal from the SIG1 field of the received signal. Search for When there is no AID of the own terminal, the multi-STA BA frame may be received by decoding a resource unit designated by broadcast or multicast (that is, a resource unit designated by broadcast ID or multicast ID). The destination address of the Multi-STA BA frame is a broadcast address or a multicast address.

  FIG. 19 is a flowchart illustrating another example of the DL-OFDMA scheduling of the access point according to the present embodiment. In the flowchart of FIG. 13, in step S101, it is determined whether or not there is a frame to be transmitted to the terminal (transmission frame) with respect to the target terminal (the terminal specified by the trigger frame or the terminal that has transmitted UL-OFDMA). However, in the scheduling of FIG. 19, it is determined whether or not there is a transmission frame for a terminal not specified in the trigger frame (hereinafter, referred to as another terminal) (S201).

  If there is no transmission frame in all of the target terminals (YES in S102) and there are no transmission frames in other terminals (YES in S202), the process of step S103 is performed as in FIG. On the other hand, if transmission frames do not exist in all of the target terminals (YES in S102), but transmission frames exist in one or more other terminals (NO in S202), the delivery acknowledgment responses of all the target terminals are sent. It decides to transmit a frame (Multi-STA BA frame) including the transmission frame, and decides to transmit the transmission frame for other terminals having the transmission frame (S203). Further, the resource unit for transmitting the Multi-STA BA frame and the resource unit for transmitting the transmission frame are determined (S203). The Multi-STA BA frame is allocated to one resource unit, and for other terminals transmitting the transmission frame, the resource unit to be allocated may be determined according to the number of other terminals and available resource units. When a Multi-STA BA frame is allocated to one resource unit, the maximum number of other terminals that can be allocated is, for example, a value obtained by subtracting 1 from the number of available resource units. The access point performs DL-OFDMA transmission according to the determination after a fixed time (SIFS time or the like) from the completion of reception of the data frames 511 to 515 transmitted by UL-OFDMA (S107). FIG. 20 shows a sequence example in this case.

  In FIG. 20, the access point transmits a Multi-STA BA frame 581 including the delivery acknowledgments of the terminals 1 to 5 in the resource unit used by the terminal 3 in UL-OFDMA transmission. Further, the data frame 586 is transmitted to the terminal 6 by UL-OFDMA using the resource unit used by the terminal 1. Also, the data frame 587 is transmitted to the terminal 7 by UL-OFDMA using the resource unit used by the terminal 2. In addition, the data frame 588 is transmitted to the terminal 8 by UL-OFDMA using a resource unit in which the resource units used by the terminals 4 and 5 are bonded. The data frames 586, 587, 588 may be an aggregation frame in which a plurality of data frames are aggregated, or may be a single data frame. The destination addresses of the data frames 586, 587, and 588 are the addresses of the terminals 6 to 8, and are different from the addresses of the terminals 1 to 5 that have performed the UL-OFDMA transmission. Note that padding data is added to the end of the Multi-STA BA frame 581, and the frame length is adjusted to the end of the other frames 586, 587, and 588.

  If there is a transmission frame for at least one of the target terminals (NO in S102) and there is one target terminal in which the transmission frame does not exist (NO in S104), the process of step S106 is performed as in FIG. Do. As a modified example, when there is a terminal having a transmission frame among the other terminals, the transmission frame of the terminal is aggregated with the acknowledgment response frame (BA frame or the like) of the one target terminal. To generate an aggregation frame. On the other hand, when there are a plurality of target terminals having no transmission frame (YES in S104), for a target terminal having no transmission frame, a frame including a delivery acknowledgment response of these target terminals (Multi-STA BA frame) is transmitted. Then, for the target terminal where the transmission frame exists, an aggregation frame in which the transmission frame and the acknowledgment response frame are aggregated is transmitted, and for the other terminal where the transmission frame exists, it is determined that the transmission frame is transmitted ( S204). In addition, a resource unit for transmitting a Multi-STA BA frame, a resource unit for transmitting an aggregation frame, and a resource unit for transmitting a transmission frame to another terminal are determined (S204). In addition, it is also possible that the target terminal is prioritized over the other terminals and more resource units are allocated, and the other terminals may not be selected as DL-OFDMA targets. The access point performs DL-OFDMA transmission according to the determination after a fixed time (SIFS time or the like) from the completion of reception of the data frames 511 to 515 transmitted by UL-OFDMA (S107). FIG. 21 shows a sequence example in this case.

  In FIG. 21, the access point transmits an aggregation frame 591 to the terminal 1 using the resource unit used for the UL-OFDMA transmission by the terminal 1, and transmits a Multi-STA BA frame 592 including delivery acknowledgments of the terminals 2 to 5 to the UL- The terminal 3 transmits the resource frame used by the terminal 3 in the OFDMA transmission, and transmits the data frame 597 to the terminal 7, which is another terminal, by the resource unit used by the terminal 2 in the UL-OFDMA transmission. Further, the data frame 598 is transmitted to the terminal 8 which is another terminal by using the resource unit used by the terminal 5 for the UL-OFDMA transmission. The data frames 597 and 598 may be an aggregation frame in which a plurality of data frames are aggregated or a single data frame. Padding data is added to the end of the Multi-STA BA frame 592, and the frame length is adjusted to the end of the other frames 591 597 598. Instead of transmitting the data frame 597, the aggregation frame 591 may be transmitted using a resource unit in which the resource unit is bonded to the resource unit for the terminal 1.

  In the description of step S105 in FIG. 13 and steps S203 and S204 in FIG. 19, the acknowledgment responses of a plurality of terminals are combined into one Multi-STA BA frame, and the Multi-STA BA frame is transmitted by one resource unit. In this case, it is desirable that the resource unit used satisfies the communication quality of the MCS necessary for transmission of the frame, common to the plurality of terminals. Hereinafter, this will be described in detail.

  When performing UL-OFDMA or DL-OFDMA with an individual terminal, the access point measures the communication quality of a plurality of resource units between the individual terminals in advance. The communication quality includes, for example, SNR (Signal to Noise Ratio). The relationship between the range of communication quality and the available MCS is defined in advance, and it is conceivable to allocate a resource unit for each terminal using this relationship. When transmitting one Multi-STA BA frame, the access point may use any of the plurality of terminals as a resource unit that satisfies the MCS communication quality required for transmitting the Multi-STA BA frame.

  At this time, the resource unit to be selected may be selected from resource units used by the plurality of terminals at the time of UL-OFDMA transmission. A resource unit for a terminal that transmits an aggregation frame (a transmission frame and a BA frame are aggregated) by DL-OFDMA may be excluded from selection targets, as the terminal uses the resource unit in principle.

  If there is no resource unit that satisfies the communication quality for a plurality of terminals to which the Multi-STA BA frame is to be transmitted in common, the acknowledgment responses of the plurality of terminals are divided into a plurality of Multi-STA BA frames and transmitted. You may. At this time, only one terminal transmits a BA frame using a resource unit for that terminal (a resource unit used in UL-OFDMA), and for other terminals, the MCS of the MCS required in common for these terminals is transmitted. The Multi-STA BA frame may be transmitted by a resource unit that satisfies the communication quality.

  FIG. 22 shows an example in which the sequence shown in FIG. 20 described above is modified so that the Multi-STA BA frame to terminals 1 to 5 is transmitted in two divided frames. In FIG. 22, the access point transmits a Multi-STA BA frame 603 including the delivery acknowledgment responses of the terminals 3 to 5 in the resource unit used by the terminal 3 in UL-OFDMA transmission. For the terminals 1 and 2, since the communication quality for the resource unit for the terminal 3 does not satisfy the required communication quality of the MCS, the multi-STA including the delivery acknowledgment response of the terminals 1 and 2 is used in the resource unit for the terminal 1. The BA frame 601 is being transmitted. In the sequence of FIG. 20, the data frame 586 is transmitted to the terminal 6 in the resource unit for the terminal 1, but the resource unit transmits the Multi-STA BA frame 601. Therefore, in the sequence example of FIG. The transmission to the terminal 6 is not performed. Note that padding data is added to the end of the Multi-STA BA frames 601 and 603, and the frame length is adjusted to the end of the other frames 587 and 588.

  By combining the delivery acknowledgment responses of a plurality of terminals in this way, a vacancy of a resource unit is generated, and a data frame can be additionally transmitted to another terminal by using the vacant resource unit.

  In the example of FIG. 22, two Multi-STA BA frames are transmitted. However, only one terminal, for example, the terminal 1 transmits the MCS required for transmitting the Multi-STA BA frame to the resource unit for the terminal 3. When the communication quality standard is not satisfied, the terminal 1 may transmit a normal BA frame. FIG. 23 shows a sequence example in this case. A BA frame 611 is transmitted to the terminal 1 in a resource unit for the terminal 1 (a resource unit used in the UL-OFDMA by the terminal 1), and a Multi- resource unit for the terminal 3 including a delivery acknowledgment of the terminals 2 to 5 is transmitted. The STA BA frame 613 is being transmitted.

  Further, when selecting a resource unit that transmits a Multi-STA BA frame, a resource unit that cannot be bonded to another resource unit may be selected. A plurality of resource units used in OFDMA may not be able to bond with other resource units depending on the resource unit bonding rules. For example, it is conceivable that a resource unit composed of two frequency components located on both sides of the position of the DC component in the frequency domain cannot be bonded to another resource unit and can be used only by itself. Therefore, when a resource unit of a Multi-STA BA frame is selected, such a resource unit is preferentially selected, so that a plurality of resources are transmitted to a terminal transmitting another frame such as a data frame or an aggregation frame. It is possible to increase the possibility of using the unit by bonding, and it is possible to allocate resource units with higher flexibility.

  In the description of step S105 in FIG. 13 and steps S203 and S204 in FIG. 19, the Multi-STA BA frame is transmitted as a single frame. However, the Multi-STA BA frame is aggregated with another type of frame to aggregate the aggregation frame. Is generated, and the aggregation frame can be transmitted. In this case, trigger frames may be aggregated as another type of frame. FIG. 24 shows an example of transmitting an aggregation frame in which a Multi-STA BA frame is aggregated with a trigger frame instead of the Multi-STA BA frame 581 in the sequence shown in FIG. 20 described above. The access point transmits an aggregation frame 621 in which a Multi-STA BA frame including delivery acknowledgments of the terminals 1 to 5 and a trigger frame are aggregated. In this trigger frame, as an example, all or a part of the terminals 1 to 5 are specified as targets for permitting UL-OFDMA (not shown) performed after a certain period of time from completion of the DL-OFDMA. In addition to all or some of the terminals 1 to 5, some or all of the terminals 6 to 8 may be included in the designated object. The configuration of the trigger frame may be the same as the examples in FIGS. As a result, the resource units can be more effectively used, and the efficiency can be increased.

  In the above description, a sequence in which the access point transmits a trigger frame, a plurality of terminals transmit UL-OFDMA in response to the trigger frame, and the access point performs DL-OFDMA transmission in response to the UL-OFDMA transmission, Is shown as a basis. However, the timing at which the access point performs DL-OFDMA transmission is not limited to this sequence. For example, the access point can acquire an access right by carrier sense on a CSMA / CA basis and perform DL-OFDMA transmission based on the access right. Also, in DL-OFDMA transmission, various transmission forms are possible, such as transmitting an aggregation frame including a trigger frame for each resource unit. Even when such a sequence is performed, efficiency can be improved by transmitting a Multi-STA BA frame including delivery acknowledgments of a plurality of terminals using one resource unit. FIG. 25 shows an example of such a sequence.

  The access point performs DL-OFDMA transmission of the aggregation frame using different resource units for the terminal 4, the terminal 1, the terminal 2, and the terminal 3, respectively. The terminal 3 uses a resource unit obtained by bonding two resource units. Each aggregation frame includes a plurality of data frames and a trigger frame. The trigger frames may all be frames having the same content, or the content may be different for each terminal. As an example, the trigger frame for terminal 4 specifies terminal 4 and the resource unit used by terminal 4, the trigger frame for terminal 1 specifies terminal 1 and the resource unit used by terminal 1, May specify the terminal 2 and the resource unit used by the terminal 2, and the trigger frame for the terminal 3 may specify the terminal 3 and the terminal 5 and the resource unit used by the terminal 3 and the terminal 5, respectively. . In this case, the receiving addresses of the trigger frames of the terminals 4, 1, and 2 may be the MAC addresses of the terminals 4, 1, and 2, and the receiving addresses of the trigger frames for the terminal 3 may be the broadcast addresses or the multicast addresses. Also, a predetermined area (such as the SIG1 field in FIG. 11) of a physical header added to the head of these frames transmitted by DL-OFDMA includes an identifier (AID or the like) of the terminal and a resource unit to be decoded by the terminal. May be stored in association with each other. When all the terminals request to decode a certain resource unit, an ID specifying all the terminals (here, called a broadcast ID for convenience) is defined, and the broadcast ID and the identifier of the resource unit are defined. They may be set in association with each other.

  The terminal 4, the terminal 1, the terminal 2, the terminal 5, and the terminal 3 receive the signal transmitted from the access point, specify the resource unit to be decoded from the physical header, decode the resource unit, and acquire the aggregation frame. The terminals 4, 1, 2, and 3 perform a CRC check on the data frame in the aggregation frame, and generate a BA frame according to the check result. In addition, a frame (here, a plurality of data frames) for uplink transmission is generated in accordance with an instruction of a trigger frame in the aggregation frame. An aggregation frame in which the plurality of data frames and the BA frame are aggregated is generated. The terminal 5 generates an uplink transmission frame (here, an aggregation frame obtained by aggregating a plurality of data frames) in accordance with an instruction in a trigger frame in the aggregation frame. Each of the terminals 4, 1, 2, 5, and 3 transmits an aggregation frame after a certain period of time from completion of DL-OFDMA reception. Thereby, UL-OFDMA is performed. In addition, when the data frame in the aggregation frame is received from the access point, but the own terminal is not specified in the trigger frame in the aggregation, the terminal transmits only the acknowledgment response frame (BA frame or the like) for a certain period of time. It may be interpreted that transmission after (SIFS time, etc.) is permitted.

  The access point receives an aggregation frame transmitted by UL-OFDMA from these terminals. At this time, it is assumed that the reception of the BA frame of the aggregation frame from the terminal 1 has failed (see the hatched lines in the frame representing the BA frame in FIG. 25). The access point generates a frame for each terminal targeted for DL-OFDMA transmission in accordance with the next DL-OFDMA scheduling. Here, since there is no data frame to be additionally transmitted to the terminals 2, 3, and 4, a Multi-STA BA frame including the delivery acknowledgment of the terminals 2, 3, and 4 is generated, and this frame and the trigger frame are generated. Generate an aggregation frame that aggregates For terminal 1, together with a BA frame including the acknowledgment of terminal 1, a retransmission frame of the frame that failed to be transmitted (see the hatched line in the frame representing the data frame for terminal 1 in FIG. 25), and a trigger frame An aggregation frame is generated by integrating Since there is a data frame to be additionally transmitted to the terminal 5, an aggregation frame is generated by integrating the data frame, the BA frame including the delivery confirmation response of the terminal 5, and the trigger frame. In addition, since there is a data frame to be transmitted to the terminal 6, an aggregation frame in which the data frame and the trigger frame are aggregated is generated. The content of the trigger frame included in each aggregation frame may be the same, or may be different from each other. The access point transmits these generated aggregation frames a fixed time after the completion of UL-OFDMA reception. Thereby, DL-OFDMA is performed. Also in this sequence, by transmitting a Multi-STA BA frame, available resource units are increased, and efficient communication is performed. Note that the combination or order of the frames in the illustrated aggregation frame is an example, and the present invention is not limited to this. In this example, the access point retransmits the frame whose transmission has failed to the terminal 1, but may transmit a BAR (Block Ack Request) frame instead.

  FIG. 26 is a functional block diagram of the wireless communication device mounted on the access point 11. As described above, the access point 11 is connected to at least the network of the terminals 1 to 8 shown in FIG. 1, and may be connected to another network. FIG. 26 shows a configuration of a wireless communication device connected to the network of the terminals 1 to 8.

  The wireless communication device of the access point 11 includes a control unit 101, a transmission unit 102, a reception unit 103, antennas 12A, 12B, 12C, 12D, and a buffer 104. Although the number of antennas is four here, it is sufficient that at least one antenna is provided. The control unit 101 corresponds to a control unit or a baseband integrated circuit that controls communication with a terminal, and the transmission unit 102 and the reception unit 103 include a wireless communication unit (Transceiver) or an RF integrated circuit that transmits and receives frames via an antenna. To form All or a part of the processing of the control unit 101 and the processing of the digital domain of the transmission unit 102 and the reception unit 103 may be performed by software (program) operating on a processor such as a CPU, or may be performed by hardware. Or may be performed by both of these software and hardware. The access point may include a processor that performs all or a part of the processing of the control unit 101, the transmission unit 102, and the reception unit 103.

  The buffer 104 is a storage unit for transferring frames and the like between the upper layer and the control unit 101. The buffer 104 may be a volatile memory such as a DRAM or a nonvolatile memory such as a NAND or an MRAM. The upper layer may store the frame received from another network in the buffer 104 for relaying to the network of the terminal 1 to 8. Further, a frame received from the terminal side network or its payload may be received from the control unit 101 via the buffer 104. The upper layer may perform communication processing higher than the MAC layer, such as TCP / IP or UDP / IP. Alternatively, the upper layer may be performed by the TCP / IP or UDP / IP control unit 101, and the upper layer may perform processing of an application layer higher than the upper layer. The operation of the upper layer may be performed by processing of software (program) by a processor such as a CPU, may be performed by hardware, or may be performed by both software and hardware.

  The control unit 101 mainly performs processing of the MAC layer and a part of processing of the physical layer (for example, processing related to OFDMA). The control unit 101 controls communication with each terminal by transmitting and receiving frames via the transmission unit 102 and the reception unit 103. In addition, the control unit 101 may control to transmit a beacon frame in order to periodically notify an attribute of a BSS (Basic Service Set) and synchronization information of the access point. Further, the control unit 101 may include a clock generation unit that generates a clock, and manage the internal time by using the clock generated by the clock generation unit. The control unit 101 may output the clock generated by the clock generation unit to the outside. Alternatively, the control unit 101 may receive an input of a clock generated by an external clock generation unit, and manage the internal time using the clock.

  The control unit 101 receives the association request from the terminal, performs an association process, and exchanges necessary information such as capabilities and attributes of each other (may include capability information indicating whether or not OFDMA can be performed). Establish a wireless link with the terminal. If necessary, an authentication process may be performed with the terminal in advance. The control unit 101 checks the state of the buffer 104 by periodically checking the buffer 104. Alternatively, the control unit 101 checks the state of the buffer 104 by a trigger from the outside (device) such as the buffer 104.

  The control unit 101 selects a plurality of terminals that specify UL-OFDMA from terminals (OFDMA-compatible terminals) that have established a wireless link at any timing, and specifies a resource unit to be used by each terminal. Further, other parameters such as a packet length (PPDU length and the like) and MCS are determined as necessary. These details are as described above. The correspondence between the resource units and the identifiers of the resource units and the information on the channels used in OFDMA may be notified to the terminal in advance, or may be determined by the system or specifications. Some or all of these pieces of information may be notified in a trigger frame. The control unit 101 sets information specifying the selected terminal, information specifying the resource unit, other parameters, and the like in the common field and / or the terminal information field in the trigger frame. In the trigger frame, information specifying a period (TXOP) for continuing the OFDMA sequence may be set in a common field. Alternatively, the period may be set as a medium reservation period in the Duration / ID field.

  The control unit 101 transmits the generated trigger frame from the transmission unit 102, for example, with a 20 MHz channel width that can be received by the legacy terminal. As an example, before transmitting, carrier sense is performed in accordance with CSMA / CA, and if an access right to a wireless medium is acquired, a trigger frame is output to transmitting section 102. The transmission unit 102 generates a physical packet by performing processing of a desired physical layer such as encoding and modulation processing and addition of a physical header to the input trigger frame. The physical packet is subjected to DA conversion, filter processing for extracting a desired band component, frequency conversion (up-conversion), and the like, and a signal obtained by these is amplified by a preamplifier and spatially converted from one or more antennas. Radiates as radio waves. Note that a transmission system may be provided for each antenna, and a physical layer process may be performed for each transmission system to transmit the same signal at the same time. Alternatively, it is possible to control transmission directivity using a plurality of antennas.

  The signal received by each antenna is processed in the receiving unit 103 for each reception system corresponding to each antenna. For example, after transmission of the trigger frame, signals of data frames (including an aggregation frame) returned by OFDMA from a plurality of terminals specified by the trigger frame are simultaneously received by each antenna. Each of the received signals is amplified by a low noise amplifier (LNA) in a receiving system, frequency-converted (down-converted), and a desired band component is extracted by a filtering process. Each of the extracted signals is further converted into a digital signal by AD conversion, and after undergoing physical layer processing such as demodulation, error correction decoding, and physical header processing, a data frame is input to the control unit 101. Here, the corresponding frequency band may be different for each reception system, and the reception system may be arranged for each resource unit. Alternatively, each reception system may correspond to the same frequency band, and signals received by these reception systems may be combined by a diversity technique. In this case, the signal of each resource unit may be extracted by digital filter processing. When OFDMA reception is not performed, it is also possible to perform reception with a configuration in which only one antenna is connected to the reception unit 103 and the other antennas are not connected to the reception unit 103.

  The control unit 101 checks the time when the transmission of the trigger frame is completed or thereafter, the time when the reception of the data frame transmitted in UL-OFDMA in response to the trigger frame is completed or thereafter, or the CRC check of the data frame described below. At any time, such as after performing the scheduling, the scheduling of the DL-OFDMA performed after a certain time of the UL-OFDMA is performed. As a modification, the scheduling may be performed before transmitting the trigger frame. An operation example of the scheduling is as described with reference to FIG. 13 or FIG.

  The control unit 101 performs a CRC check on data frames simultaneously received by UL-OFDMA from each terminal (in the case of an aggregation frame, a CRC check is performed for each of a plurality of data frames in the aggregation frame). The control unit 101 generates a frame to be transmitted to a plurality of terminals to be subjected to DL-OFDMA transmission based on the scheduling result, and allocates the frame to a resource unit (including a bonded resource unit).

  After a predetermined time from the completion of the reception of the data frame from each terminal in UL-OFDMA, the control unit 101 transmits the generated frame to the plurality of terminals determined by the scheduling result using the corresponding resource units for the plurality of terminals. Control to send from. The transmission unit 102 generates a physical packet by performing desired physical layer processing such as encoding and modulation processing and adding a physical header to each frame. The physical packet is subjected to DA conversion, filter processing for extracting a desired band component, frequency conversion (up-conversion), and the like, and a signal obtained by these is amplified by a preamplifier and spatially converted from one or more antennas. Radiates as radio waves.

  Note that the control unit 101 may access a storage device for storing information notified to each terminal by a trigger frame or the like, information notified from each terminal, or both, and read the information. The storage device may be an internal memory or an external memory, and may be a volatile memory or a nonvolatile memory. The storage device may be an SSD, a hard disk, or the like, in addition to the memory.

  The above-described separation between the processes of the control unit 101 and the transmission unit 102 is merely an example, and another form different from the above-described form is also possible. For example, the processing up to the digital domain and the DA conversion may be performed by the control unit 101, and the processing after the DA conversion may be performed by the transmission unit 102. Similarly, the process of the control unit 101 and the process of the receiving unit 103 are separated by the process performed before the AD conversion by the receiving unit 103, and the process of the digital domain including the process after the AD conversion is performed by the control unit 101. You may. As an example, the baseband integrated circuit according to the present embodiment includes a control unit 101, a part that performs processing of the physical layer in the transmission unit 102, a part that performs DA conversion, and a part that performs processing after AD conversion in the reception unit 103. In this case, the RF integrated circuit corresponds to a part that performs processing after DA conversion in the transmission unit 102 and a part that performs processing before AD conversion in the reception unit 103. The wireless communication integrated circuit according to the present embodiment includes at least the baseband integrated circuit among the baseband integrated circuit and the RF integrated circuit. Processing between blocks or processing between a baseband integrated circuit and an RF integrated circuit may be separated by a method other than the method described here.

  FIG. 27 is a functional block diagram of a wireless communication device mounted on a terminal. Each of the wireless communication devices mounted on the terminals 1 to 8 in FIG. 1 has the configuration in FIG.

  The wireless communication device includes a control unit 201, a transmission unit 202, a reception unit 203, at least one antenna 1A, and a buffer 204. The control unit 201 corresponds to a control unit or a baseband integrated circuit that controls communication with the access point 11, and the transmission unit 202 and the reception unit 203 correspond to a wireless communication unit (Transceiver) or an RF integrated circuit that transmits and receives frames. I do. All or a part of the processing of the control unit 201 and the processing of the digital domain of the transmission unit 202 and the reception unit 203 may be performed by software (program) operated by a processor such as a CPU, or may be performed by hardware. Or may be performed by both of these software and hardware. The terminal may include a processor that performs all or a part of the processing of the control unit 201, the transmission unit 202, and the reception unit 203.

  The buffer 204 is a storage unit for transferring frames and the like between the upper layer and the control unit 201. The buffer 204 may be a volatile memory such as a DRAM or a non-volatile memory such as a NAND or MRAM. The upper layer generates a frame to be transmitted to another terminal, an access point 11, or a device on another network such as a server, and stores the frame in the buffer 204 or receives the frame from another terminal, the access point 11 or the device. The received frame is received from the control unit 201 via the buffer 204. The upper layer may perform communication processing higher than the MAC layer, such as TCP / IP or UDP / IP. Further, TCP / IP and UDP / IP may be processed by the control unit 201, and the upper layer may perform processing of an application layer higher than this. The operation of the upper layer may be performed by processing of software (program) by a processor such as a CPU, may be performed by hardware, or may be performed by both software and hardware.

  The control unit 201 mainly performs a part of processing of the MAC layer and processing of the physical layer (for example, processing related to OFDMA). The control unit 201 controls communication with the access point 11 by transmitting and receiving frames to and from the access point 11 via the transmission unit 202 and the reception unit 203. Further, the control unit 201 may include a clock generation unit that generates a clock, and may manage the internal time by using the clock generated by the clock generation unit. The control unit 201 may output the clock generated by the clock generation unit to the outside. Alternatively, the control unit 201 may receive an input of a clock generated by an external clock generation unit, and manage the internal time using the clock.

  As an example, the control unit 201 receives a beacon frame, grasps the attribute of the BSS of the access point 11 and the synchronization information, and then makes an association request to the access point 11 to perform an association process. Thus, by exchanging necessary information such as mutual capabilities and attributes (which may include capability information indicating whether or not OFDMA can be performed), a wireless link with the access point 11 is established. If necessary, an authentication process may be performed with the access point in advance. The control unit 201 checks the state of the buffer 204 by periodically checking the buffer 204. Alternatively, the control unit 201 checks the state of the buffer 204 by a trigger from the outside (device) such as the buffer 204. After confirming the existence of a frame such as a data frame to be transmitted to the access point 11, the control unit 201 acquires an access right (transmission right) to the wireless medium based on CSMA / CA or the like, and then transmits the frame to the transmission unit 202 and You may transmit via antenna 1A.

  The transmission unit 202 generates a physical packet by performing a desired physical layer process such as encoding and modulation processes and adding a physical header to the frame input from the control unit 201. In addition, the physical packet is subjected to DA conversion, filter processing for extracting a desired band component, frequency conversion (up-conversion), and the like, and a signal obtained by these is amplified by a preamplifier to obtain one or more antennas. Radiates as radio waves into space. When a plurality of antennas are provided, a transmission system may be provided for each antenna, and processing of the physical layer may be performed for each transmission system to transmit the same signal at the same time. Alternatively, it is possible to control transmission directivity using a plurality of antennas.

  The signal received by antenna 1A is processed in receiving section 203. The received signal is amplified by the LNA in the receiving unit 203, frequency-converted (down-converted), and a desired band component is extracted by a filtering process. The extracted signal is further converted to a digital signal by AD conversion, and after undergoing physical layer processing such as demodulation, error correction decoding, and physical header processing, a frame such as a data frame is input to the control unit 201. .

  When a trigger frame is received from the access point 11, the control unit 201 confirms whether or not the own terminal is specified as a target of UL-OFDMA in the trigger frame. As described above, the method of checking may be to check whether the identification information of the own terminal is stored in any of the terminal information fields or the common field. Alternatively, if a group ID is specified in the common field and there is a rule that all terminals belonging to the group ID are permitted as targets of OFDMA, the own terminal is designated as belonging to the group ID. May be determined. In this case, the terminal acquires a list of terminals belonging to each group (or information related to the list) from the access point 11. Further, when information on the period of the OFDMA sequence is set in the Duration / ID field or the common information field of the trigger frame, the control unit 201 grasps the period of the OFDMA sequence based on the information. The terminal may, for example, decide not to perform single user transmission on a CSMA / CA basis during this period.

  When the own terminal is specified as a target of UL-OFDMA, the control unit 201 transmits information of the resource unit and other parameters used by the own terminal to a common field or a terminal information field or these Get from both. The control unit 201 reads the data frame stored in the buffer 204 according to the information and controls the data frame to be transmitted to the access point 11 after a predetermined time has elapsed from the reception of the trigger frame. As an example of the data frame to be read, for example, when a packet length (PPDU length or the like) is specified, the data frame is selected and read so that the packet to be transmitted is shorter than the packet length. When the access category is specified, the data frame of the specified access category is read. An aggregation frame may be generated by reading a plurality of data frames. If the packet length is less than the specified packet length, padding data may be added to the end of the data frame. When the amount of tying adjustment to be transmitted is specified, the trigger frame is transmitted at a timing shifted from the predetermined time by the amount of adjustment with respect to a predetermined time. The data frame is transmitted as a physical packet via transmitting section 202 and antenna 1A. The operation of the transmitting unit 202 is as described above.

  After transmitting the data frame, control section 201 receives a signal transmitted by DL-OFDMA from access point 11. The control unit 201 specifies the resource unit specified for the terminal from a predetermined field (eg, the SIG1 field in FIG. 11) of the physical header. When receiving the signal transmitted by the DL-OFDMA when the own terminal is not specified in the trigger frame, the control unit 201 checks whether there is a resource unit specified for the own terminal in the predetermined field. .

The control unit 201 obtains a frame by decoding the signal of the resource unit designated to the own terminal. The acquired frame is a delivery confirmation response frame (BA frame, Multi-STA
If it is a BA frame, an ACK frame, or the like), it specifies whether the transmission of the own terminal is successful (whether the data frame transmitted by the own terminal is correctly received by the access point 11).

  If the acquired frame is an aggregation frame including a delivery acknowledgment frame and a data frame, the terminal determines whether or not the terminal itself has succeeded in transmission based on the delivery acknowledgment frame, and performs a CRC check on the data frame. If the acquired frame is a data frame, a CRC check of the data frame is performed (in the case of an aggregation frame including a plurality of data frames, a CRC check is performed for each data frame).

  When a data frame is received from the access point, if there is a rule that the uplink transmission can be continued after a fixed time (SIFS time) after the completion of the reception, the acknowledgment frame is sent to the data frame when the reception is completed. After a certain time from, the data frame may be transmitted in the same resource unit as that in which the data frame was received or in a resource unit determined in another way. Or, when the trigger frame is included in the aggregation frame in the current DL-OFDMA, and the own terminal is specified in the trigger frame, according to the specification in the trigger frame, the delivery confirmation response frame, or the delivery confirmation frame An aggregation frame including a data frame may be transmitted.

  The control unit 201 performs a data frame retransmission process as necessary for a data frame determined to have failed in transmission. The retransmission method may be arbitrary. For example, when the own terminal is designated by the next trigger frame, the data frame may be retransmitted by UL-OFDMA. Alternatively, when the trigger frame is also included in the aggregation frame in the current DL-OFDMA, and the own terminal is specified in the trigger frame, the data frame may be transmitted according to the specification in the trigger frame. Alternatively, after the end of the OFDMA sequence period, an access right may be acquired by transmitting / receiving a CSMA / CA base or an RTS frame and a CTS frame, and a data frame may be retransmitted (single user transmission). Retransmission may be performed by a method other than these.

  Here, the case where the frame transmitted by UL-OFDMA is mainly a data frame has been described as an example, but may be a management frame or a control frame.

  The control unit 201 may access a storage device for storing information notified to the access point 11, information notified from the access point 11, or both, and read the information. The storage device may be an internal memory or an external memory, and may be a volatile memory or a nonvolatile memory. The storage device may be an SSD, a hard disk, or the like, in addition to the memory.

  The above-described separation of the processes of the control unit 201 and the transmission unit 202 is an example, and another mode different from the above-described mode is also possible. For example, the processing up to the digital domain and the DA conversion may be performed by the control unit 201, and the processing after the DA conversion may be performed by the transmission unit 202. Similarly, the processing of the control unit 201 and the receiving unit 203 is separated by performing the processing before AD conversion by the receiving unit 203, and performing the processing of the digital domain including the processing after AD conversion by the control unit 201. Is also good. As an example, the baseband integrated circuit according to the present embodiment includes a control unit 201, a part that performs processing of the physical layer in the transmission unit 202, a part that performs DA conversion, and a part that performs processing after AD conversion in the reception unit 203. In this case, the RF integrated circuit corresponds to a part that performs processing after DA conversion in the transmission unit 202 and a part that performs processing before AD conversion in the reception unit 203. The wireless communication integrated circuit according to the present embodiment includes at least the baseband integrated circuit among the baseband integrated circuit and the RF integrated circuit. Processing between blocks or processing between a baseband integrated circuit and an RF integrated circuit may be separated by a method other than the method described here.

  FIG. 28 is a flowchart of the operation of the access point according to the first embodiment. The control unit 101 of the access point selects a plurality of terminals (or a plurality of wireless communication devices) to be subjected to UL-OFDMA, and selects a resource unit to be used by the selected terminal (S301). Also, if necessary, parameters such as MCS or packet length are determined. A trigger frame in which information specifying the selected terminal and resource unit and information on the determined parameter is set is generated (S302). After acquiring the access right for transmitting the trigger frame by carrier sense or the like, the control unit 101 of the access point transmits the trigger frame via the transmitting unit 101 (S303).

  After transmitting the trigger frame, the control unit 101 of the access point performs DL-OFDMA scheduling that is performed a fixed time after the completion of the UL-OFDMA execution (S304). The details of the scheduling are as described with reference to FIG. 13 or FIG.

  The control unit 101 of the access point waits for reception of a frame such as a data frame transmitted by the specified resource unit from each of the terminals specified by the trigger frame. The control unit 101 simultaneously receives frames such as data frames multiplexed and transmitted from these terminals via the receiving unit 102 (S305). The control unit 101 performs a check (such as a CRC check) on whether or not each of the frames has been successfully received. The control unit 101 generates a plurality of frames for a plurality of terminals based on the inspection result (CRC result) regarding the success or failure of the reception of the frame and the result of the scheduling in step S304 (S306). After completing the reception of the frames multiplexed from the plurality of terminals in step S305, the control unit 101 transmits the generated plurality of frames (DL-OFDMA transmission) after a predetermined time has elapsed (S307).

  FIG. 29 is a flowchart of the operation of the terminal according to the first embodiment. The control unit 201 of the terminal receives the trigger frame transmitted from the access point via the receiving unit 202 (S401). In the trigger frame, information for specifying a plurality of terminals as targets of UL-OFDMA, information for specifying a resource unit used by each terminal, and other information regarding necessary parameters include a common field or a terminal information field or a field for these. Both are set.

  The control unit 201 of the terminal checks whether or not the own terminal is designated as a target of UL-OFDMA in the trigger frame (S402). If so, the resource unit used by the own terminal and, if necessary, Understand the parameters required for transmission. A frame such as a data frame (here, a data frame) is generated in accordance with the parameter, and after a predetermined time elapses from completion of reception of the trigger frame, the data frame (more specifically, a physical packet including the data frame) is generated. Then, using the resource unit designated by the trigger frame, the transmission unit 202 transmits the resource unit to the access point (S403).

  After the transmission of the data frame, the control unit 201 of the terminal receives the frame transmitted from the access point after a predetermined time has elapsed (S404). More specifically, a frame is obtained by specifying a resource unit designated to the own terminal from a predetermined field in a physical header added to a frame transmitted from an access point and decoding a signal of the resource unit. I do. The control unit 201 analyzes the frame, determines whether the frame is a BA frame, a Multi-STA BA frame, an aggregation frame in which a plurality of frames are aggregated, and the like, and operates according to the determination result (S405). If there is a trigger frame in the aggregation frame, the same processing may be repeated from step S401. If the destination address of the acquired frame is the broadcast address, the multicast address to which the terminal belongs, or the MAC address of the terminal, the terminal processes the frame.

  In the present embodiment, UL-OFDMA is used for uplink multiplex transmission and DL-OFDMA is used for downlink multiplex transmission. Instead, each of the uplink multi-user MIMO (Multi-Input Multi-Output) (UL-OFDMA) is used. MU-MIMO) and downlink multi-user MIMO (DL-MU-MIMO) can also be used. In DL-MU-MIMO, an access point uses a technique called beamforming to transmit frames to each terminal using spatially orthogonal beams. These orthogonal beams correspond to the communication resources of the terminal. In UL-MU-MIMO, a plurality of terminals transmit frames at the same timing and in the same frequency band. At this time, the access point decodes the frame using the uplink channel response with each terminal.

  In UL-MU-MIMO, the access point 11 needs to spatially separate data frames from data streams received simultaneously from the wireless terminals 1 to 4. For this purpose, the access point 11 uses the uplink channel response with each of the wireless terminals 1-4. The access point can estimate the uplink radio channel response of each terminal by using a preamble added to the head side of a frame in which a plurality of terminals perform UL-MU-MIMO transmission. These preambles correspond to the communication resources according to the present embodiment. Hereinafter, the preamble will be described.

  The preamble is composed of a known bit string. The access point 11 can correctly and spatially separate (decode) a field (for example, a data field) after the preamble by estimating an uplink channel response using a known bit string. This can be performed using a known method, for example, an arbitrary method such as a ZF (Zero-Forcing) method, an MMSE (Minimum Mean Square Error) method, or a maximum likelihood estimation method. The preamble field is arranged, for example, in a physical header (PHY header) arranged at the head of the MAC frame. In each field before the preamble field in the physical header, the same signal is transmitted from each terminal. The preambles of each wireless terminal need to be orthogonal to each other. The orthogonality of the preambles means that the access point 11 can individually specify a preamble for each wireless terminal from signals received simultaneously from each wireless terminal. Thereby, the access point 11 can estimate the propagation path from each wireless terminal to the access point 11 using the preamble for each wireless terminal.

  Any of temporal, frequency, and code methods may be used as a method of orthogonalizing the preamble between wireless terminals. In the case of time orthogonality, the preamble field is divided into a plurality of sections, and each terminal transmits the preamble in a section different from each other. In a certain section, only one terminal is transmitting the preamble. That is, the temporal position at which the preamble is transmitted differs between the terminals. While one terminal transmits a preamble, another terminal does not transmit anything. In the case of time orthogonality, the preamble includes not only the data of the preamble to be transmitted, but also information on when to transmit. In the case of frequency orthogonality, each terminal transmits preamble data at frequencies orthogonal to each other. In the case of frequency orthogonality, the preamble also includes information on which frequency (subcarrier) to transmit. In the case of code orthogonality, each terminal transmits data in which a plurality of values (symbols corresponding to each of a plurality of values) included in different rows (or different columns) of the orthogonal matrix are arranged. Each row (or each column) of the orthogonal matrix is orthogonal to each other. With any of the orthogonalization methods, the access point 11 can identify the preamble of each terminal.

  In order for each wireless terminal to use a preamble that is orthogonal to each other, information on the preamble used by each wireless terminal needs to be given. Specifically, in the case of time orthogonal, the preamble is transmitted at each timing. Information on whether to transmit the preamble at which frequency in the case of frequency orthogonal, and which coding pattern (pattern of which row or column of the orthogonal matrix) to transmit the preamble in the case of code orthogonal. Is required. This information may be set in each of the wireless terminals that permit the UL-MU-MIMO transmission in the trigger frame transmitted by the access point 11. Alternatively, this information may be notified to each wireless terminal in advance by another method. In any case, when each wireless terminal performs UL-MU-MIMO transmission, the information of the preamble used by each wireless terminal can be grasped by some method.

  As another multiplexing transmission method, a communication method (referred to as OFDMA & MU-MIMO) combining OFDMA and MU-MIMO (Multiple-Input Multiple-Output) is also possible. In the case of OFDMA & MU-MIMO, a plurality of terminals perform MU-MIMO transmission using the same resource unit.

  As described above, the multiplex transmission used in the present embodiment can be any of OFDMA, MU-MIMO, and a combination thereof.

  As described above, according to the present embodiment, when performing multiplex communication with a plurality of terminals, efficient communication can be performed.

(Second embodiment)
When the access point performs DL-OFDMA transmission, as described in the description of the first embodiment, not only one type of frame but also a plurality of types of frames can be transmitted to a plurality of terminals. For example, as shown in FIG. 30, it is also possible to transmit data frames to terminals 1, 2, and 3 and trigger frames to terminals 4 and 5 by using DL-OFDMA using different resource units. “Trigger to STA 4” means that the destination address of the trigger frame transmitted to the terminal 4 is the MAC address of the terminal 4. In such a case, there may be a frame to be transmitted with the highest possible MCS and a frame that may have a low MCS depending on the type of the frame. For example, it is desired to improve the efficiency by sending a data frame with the highest possible MCS. On the other hand, a trigger frame or a BA frame has a short frame length and has a restriction on the transmission / reception rate according to the specification. Therefore, if the specified rate is satisfied, it is considered that there is no problem even with a low MCS. In addition, the communication quality of each resource unit or the communication quality of a channel width band (a band including a plurality of resource units) is usually different among a plurality of terminals, and the communication quality of the same terminal is usually different depending on the resource unit. In the present embodiment, when DL-OFDMA transmission of a plurality of types of frames is performed, communication quality for each resource unit for each terminal, communication quality for a channel width band (a band including a plurality of resource units) for each terminal, Also, the present invention relates to performing efficient scheduling according to the type of frame transmitted for each terminal.

  FIG. 31 is a flowchart illustrating an example of a scheduling operation performed by the control unit of the access point according to the second embodiment. The access point measures in advance the communication quality of a plurality of resource units available for OFDMA with each of the plurality of terminals. Here, the communication quality is SNR (Signal to Noise Ratio), but is not limited to this. For example, an RSSI (Received Signal Strength Indicator) may be used. The SNR may be a value measured for each resource unit on the terminal side, a value measured for each resource unit on the access point side, or a value such as an average of both. In addition, an average of SNRs of a plurality of resource units is calculated as an average SNR for each terminal. Instead of calculating the average SNR, the SNR of a band having a channel width (for example, a 20 MHz channel width) including a plurality of resource units may be measured and used. The access point may measure the communication quality with each terminal periodically, may measure it when it decides to execute DL-OFDMA, or may measure it at another timing.

The access point sorts a plurality of terminals (target terminals) selected as targets of DL-OFDMA in order of a low average SNR (S501). When there are N terminals, the terminals are described as STA ₁ , STA ₂ ,..., STA _{n in} ascending order of average SNR. An arbitrary terminal is described as STA _i . The terminal STA _i having the lowest average SNR (that is, STA ₁ ) is selected, and it is checked whether the frame of the terminal is a data frame (S502). In the case of a data frame, a resource unit selected from a plurality of available resource units is allocated to the terminal (S504). The resource unit to be selected is, for example, a resource unit having the highest SNR for the terminal. When a plurality of resource units are bonded and allocated, as an example, a set of resource units having the largest average or total SNR of the plurality of bonded resource units may be selected. The example of selecting the resource unit shown here is an example, and the resource unit may be selected by another method. The access point selects a terminal with the next lowest average SNR (selects a terminal with i incremented by 1) from among terminals to which resource units have not been allocated yet (S505, S506), and returns to step S502.

  If the access point determines in step S502 that the frame of the terminal STAi is not a data frame, there is a terminal to which the data frame is to be transmitted among other target terminals to which the resource unit has not been allocated yet. Is determined (S503). A frame that is not a data frame is a control frame or a management frame. For example, there can be a trigger frame, a BA frame, a Multi-STA frame, an ACK frame, and the like.

  If such a terminal does not exist, a resource unit is allocated to the terminal STAi determined in step S502 (S504). The resource unit to be allocated may be, for example, any resource unit that has not yet been allocated and that satisfies a predetermined MCS communication quality required for transmitting a frame (not a data frame). The resource unit having the highest SNR for the terminal STAi among the various resource units may be used. On the other hand, when there is a terminal to which the data frame is to be transmitted among the other target terminals, resource allocation to the terminal STAi determined in step S502 is skipped, and a terminal having the next lowest average SNR is selected ( The terminal that increments i is selected) (S505, S506).

  Thereafter, the same processing is repeated until resource units are allocated to all terminals. To update i when the value of i is n in step S505, i is returned to the initial value. That is, a terminal having the lowest average SNR is selected from terminals to which resource units have not been allocated yet.

  By performing scheduling as described above, the possibility of successful transmission of a plurality of frames to be transmitted to a plurality of terminals by DL-OFDMA can be increased, and efficient communication can be performed.

  FIG. 32 is a flowchart illustrating an example of a scheduling operation performed by the control unit of the access point according to the second embodiment. The access point measures the communication quality with each terminal in advance in the same manner as described with reference to FIG. The access point prepares a list of available resource units as a candidate list.

The access point sorts a plurality of terminals (target terminals) selected as targets of DL-OFDMA in order of a low average SNR (S601). When there are N terminals, the terminals are described as STA ₁ , STA ₂ ,..., STA _{n in} ascending order of SNR. An arbitrary terminal is described as STA _i . The terminal STA _i having the lowest average SNR (that is, STA ₁ ) is selected, and it is checked whether the frame of the terminal is a data frame (S602). If it is not a data frame (in the case of a non-data frame), all resource units that satisfy a predetermined MCS and are not yet selected are selected from the candidate list, and are temporarily allocated to the terminal as candidate resource units (S603). ). At this time, the resource unit finally allocated to the terminal has not been determined yet. At this time, the temporarily allocated resource unit is deleted from the candidate list.

  If the frame of the terminal is a data frame, the candidate list or the plurality of candidate resource units temporarily allocated to the terminal in step S603 (when remaining) exist in the candidate list. Select a resource unit from the resource units. Then, the selected resource unit is allocated to the terminal (S604). The resource unit to be selected is, for example, a resource unit having the highest SNR for the terminal. When a resource unit is assigned from the candidate list, the resource unit is deleted from the candidate list (S605). If a resource unit has been allocated from the candidate resource units temporarily allocated to the terminal in step S603, the allocated resource unit is deleted from the candidate resource units of the terminal. As a result, when the number of candidate resource units becomes one, it is determined that the one candidate resource unit is allocated to the terminal.

  After step S605, the access point selects a terminal with the next lowest average SNR (selects a terminal with i incremented by 1) (S606, S607), and returns to step S602.

  Thereafter, the same processing is repeated until resource units are allocated to all terminals.

  By performing scheduling as described above, the possibility of successful transmission of a plurality of frames to be transmitted to a plurality of terminals by DL-OFDMA can be increased, and efficient communication can be performed.

FIG. 33 is a diagram for describing a specific example of the operation in FIG. 32. First, it is assumed that resource units 1 to 4 are registered in the candidate list. The four terminals are arranged in the order of STA ₁ , STA ₂ , STA ₃ , and STA ₄ in ascending order of the average SNR. First, the terminal STA ₁ is selected, and since the frame of the STA ₁ is a data frame, the resource unit 2 having the highest SNR for the terminal STA ₁ is selected from the candidate list and assigned (upper left in the figure). The resource unit 2 is deleted from the candidate list.

Then select the terminal STA _2, the frame terminal STA ₂ is for a BA frame (non-data frames) to identify all the resource units satisfying a predetermined MCS from a resource unit remaining in the candidate list. Here, resource units 1 and 3 are specified, and these are temporarily assigned to terminal STA ₂ as candidate resource units (upper right in the figure). The resource units 1 and 3 are deleted from the candidate list.

Next, the terminal STA ₃ is selected. Since the frame of the terminal STA ₃ is a data frame, the SNR of the terminal STA ₃ is the highest for the terminal STA ₃ from the candidate list and the candidate resource units 1 and 3 temporarily allocated to the terminal STA _2. Assign a higher resource unit 3. At this time, the candidate resource unit of the terminal STA _2, resource unit 3 is removed, it becomes only the resource unit 1. In this case, the resource unit to be allocated to the terminal STA ₂ is determined in the resource unit 1.

Next, the terminal STA ₄ is selected, and since the frame of the terminal STA ₄ is a data frame, a resource unit having the highest SNR for the terminal STA ₄ (here, resource unit 4) is allocated from the candidate list. Since the terminal is assigned a plurality of candidate resource unit does not exist at this time, the terminal STA _4, assignment of resource units from the candidate resource unit is not performed.

(Third embodiment)
FIG. 34 shows an example of the overall configuration of a terminal (terminal of a non-access point) or an access point. This configuration example is an example, and the present embodiment is not limited to this. The terminal or the access point includes one or a plurality of antennas 1 to n (n is an integer of 1 or more), a wireless LAN module 148, and a host system 149. The wireless LAN module 148 corresponds to the wireless communication device according to any one of the first and second embodiments. The wireless LAN module 148 has a host interface, and is connected to the host system 149 via the host interface. In addition to being connected to the host system 149 via a connection cable, it may be directly connected to the host system 149. Further, a configuration is also possible in which the wireless LAN module 148 is mounted on a board with solder or the like and connected to the host system 149 via wiring on the board. The host system 149 communicates with an external device using the wireless LAN module 148 and the antennas 1 to n according to an arbitrary communication protocol. The communication protocol may include TCP / IP and higher-layer protocols. Alternatively, TCP / IP may be mounted on the wireless LAN module 148, and the host system 149 may execute a higher-layer protocol. In this case, the configuration of the host system 149 can be simplified. The access point and the terminal according to the present embodiment include, for example, a mobile terminal, a TV, a digital camera, a wearable device, a tablet, a smartphone, a game device, a network storage device, a monitor, a digital audio player, a Web camera, a video camera, a project, Navigation systems, external adapters, internal adapters, set-top boxes, gateways, printer servers, mobile access points, routers, enterprise / service provider access points, portable devices, handheld devices, automobiles, etc. In addition, the wireless LAN module 148 may have a function of another wireless communication standard (cellular communication standard such as LTE, LTE-Advanced) in addition to the IEEE 802.11 standard.

  FIG. 35 illustrates a hardware configuration example of the wireless LAN module. This configuration can be applied to a case where the wireless communication device is mounted on both a non-access point terminal and an access point. That is, it can be applied as an example of a specific configuration of the wireless communication device shown in FIG. 26 or FIG. In this configuration example, there is only one antenna, but two or more antennas may be provided. In this case, a plurality of sets of a transmission system (216, 222 to 225), a reception system (217, 232 to 235), a PLL 242, a crystal oscillator 243, and a switch 245 are arranged corresponding to each antenna, and each set is a base. It may be connected to a band circuit (control circuit) 212.

  The wireless LAN module (wireless communication device) includes a baseband IC (Integrated Circuit) 211, an RF (Radio Frequency) IC 221, a balun 225, a switch 245, and an antenna 247.

  The baseband IC 211 includes a baseband circuit (control circuit) 212, a memory 213, a host interface 214, a CPU 215, a DAC (Digital to Analog Converter) 216, and an ADC (Analog to Digital Converter) 217.

  The baseband IC 211 and the RF IC 221 may be formed on the same substrate. Further, the baseband IC 211 and the RF IC 221 may be formed by one chip. DAC 216 and / or ADC 217 may be located on RF IC 221 or on another IC. In addition, both or one of the memory 213 and the CPU 215 may be arranged in an IC different from the baseband IC.

  The memory 213 stores data to be transferred to and from the host system. The memory 213 stores information notified to the terminal or the access point, information notified from the terminal or the access point, or both. Further, the memory 213 may store a program necessary for the CPU 215 to execute, and may be used as a work area when the CPU 215 executes the program. The memory 213 may be a volatile memory such as an SRAM or a DRAM, or a nonvolatile memory such as a NAND or an MRAM.

  The host interface 214 is an interface for connecting to a host system. The interface may be anything such as UART, SPI, SDIO, USB, PCI Express, and the like.

  The CPU 215 is a processor that controls the baseband circuit 212 by executing a program. The baseband circuit 212 mainly performs processing of the MAC layer and processing of the physical layer. The baseband circuit 212, the CPU 215, or both of them correspond to a control unit that controls communication.

  At least one of the baseband circuit 212 and the CPU 215 includes a clock generation unit that generates a clock, and the internal time may be managed by the clock generated by the clock generation unit.

  The baseband circuit 212 performs, for example, addition of a physical header, encoding, encryption, and modulation processing (may include MIMO modulation) as processing of a physical layer on a frame to be transmitted, and performs, for example, two types of digital baseband signals ( Hereinafter, a digital I signal and a digital Q signal) are generated.

  The DAC 216 performs DA conversion of a signal input from the baseband circuit 212. More specifically, DAC 216 converts a digital I signal to an analog I signal and a digital Q signal to an analog Q signal. It is to be noted that there is a case where a signal of one system is transmitted without performing quadrature modulation. When a plurality of antennas are provided and one system or a plurality of systems of transmission signals are distributed by the number of antennas and transmitted, DACs and the like may be provided in a number corresponding to the number of antennas.

  The RF IC 221 is, for example, an RF analog IC, a high-frequency IC, or both. The RF IC 221 includes a filter 222, a mixer 223, a preamplifier (PA) 224, a PLL (Phase Locked Loop: phase locked loop) 242, a low noise amplifier (LNA) 234, a balun 235, a mixer 233, and a filter 232. Some of these elements may be located on baseband IC 211 or another IC. The filters 222 and 232 may be band-pass filters or low-pass filters.

  The filter 222 extracts a signal of a desired band from each of the analog I signal and the analog Q signal input from the DAC 216. The PLL 242 uses an oscillation signal input from the crystal oscillator 243 and generates a signal of a fixed frequency synchronized with the phase of the input signal by dividing or multiplying the oscillation signal or both. Note that the PLL 242 includes a VCO (Voltage Controlled Oscillator), and performs a feedback control using the VCO based on an oscillation signal input from the crystal oscillator 243 to obtain a signal of the constant frequency. The generated constant frequency signal is input to mixers 223 and 233. PLL 242 is equivalent to an example of a transmitting device that generates a signal of a constant frequency.

  The mixer 223 up-converts the analog I signal and the analog Q signal that have passed through the filter 222 to a radio frequency using a signal of a constant frequency supplied from the PLL 242. The PA 224 amplifies the radio frequency analog I signal and analog Q signal generated by the mixer 223 to a desired output power. The balun 225 is a converter for converting a balanced signal (differential signal) into an unbalanced signal (single-ended signal). The balanced signal is handled by the RF IC 221, but the unbalanced signal is handled from the output of the RF IC 221 to the antenna 247, so that these signals are converted by the balun 225.

  The switch 245 is connected to the balun 225 on the transmitting side when transmitting, and is connected to the LNA 234 or the RF IC 221 on the receiving side when receiving. The control of the switch 245 may be performed by the baseband IC 211 or the RF IC 221. Alternatively, another circuit for controlling the switch 245 may be provided, and the switch 245 may be controlled from the circuit.

  The analog I signal and analog Q signal of the radio frequency amplified by the preamplifier 224 are balanced-unbalanced converted by the balun 225 and then radiated from the antenna 247 into space as radio waves.

  The antenna 247 may be a chip antenna, an antenna formed by wiring on a printed circuit board, or an antenna formed using a linear conductor element.

  The LNA 234 in the RF IC 221 amplifies a signal received from the antenna 247 via the switch 245 to a level that allows demodulation while keeping noise low. The balun 235 performs unbalanced-balanced conversion of the signal amplified by the low noise amplifier (LNA) 234. Mixer 233 down-converts the received signal converted into a balanced signal by balun 235 to baseband using a signal of a constant frequency input from PLL 242. More specifically, the mixer 233 has a unit that generates carrier waves that are 90 ° out of phase with each other based on the constant frequency signal input from the PLL 242, and converts the received signals converted by the balun 235 into 90 ° Quadrature demodulation is performed by the carrier wave having a phase shift to generate an I (In-phase) signal having the same phase as the received signal and a Q (Quad-phase) signal delayed by 90 ° from the received signal. The filter 232 extracts a signal of a desired frequency component from the I signal and the Q signal. The I signal and the Q signal extracted by the filter 232 are output from the RF IC 221 after the gain is adjusted.

  The ADC 217 in the baseband IC 211 converts the input signal from the RF IC 221 from analog to digital. More specifically, ADC 217 converts the I signal to a digital I signal and converts the Q signal to a digital Q signal. In some cases, only one system of signals is received without performing quadrature demodulation.

  When a plurality of antennas are provided, a number of ADCs corresponding to the number of antennas may be provided. The baseband circuit 212 performs physical layer processing (may include MIMO demodulation) such as demodulation processing, error correction code processing, and physical header processing based on the digital I signal and digital Q signal, and obtains a frame. The baseband circuit 212 performs MAC layer processing on the frame. Note that, when TCP / IP is implemented, the baseband circuit 212 may be configured to perform TCP / IP processing.

  Details of the processing of each unit described above are obvious from the description of FIG. 26 and FIG. 27, and thus redundant description will be omitted.

(Fourth embodiment)
FIGS. 36A and 36B are perspective views of a wireless terminal according to the fourth embodiment. The wireless terminal in FIG. 36A is the notebook PC 301, and the wireless terminal in FIG. 36B is the mobile wireless terminal 321. The wireless terminal according to the present embodiment is one form of the access point and the terminal in the first to third embodiments. The notebook PC 301 and the mobile wireless terminal 321 are equipped with wireless communication devices 305 and 315, respectively. As the wireless communication devices 305 and 315, the wireless communication devices mounted on the wireless terminals described above (FIGS. 27 and 35) or the wireless communication devices mounted on the access point 11 (FIGS. 26 and 35) Etc.), or both. Wireless terminals equipped with wireless communication devices are not limited to notebook PCs and mobile wireless terminals. For example, TV, digital camera, wearable device, tablet, smartphone, game device, network storage device, monitor, digital audio player, web camera, video camera, project, navigation system, external adapter, internal adapter, set-top box, gateway, It can be installed in printer servers, mobile access points, routers, enterprise / service provider access points, portable devices, handheld devices, automobiles, and the like.

  In addition, the wireless communication device mounted on the wireless terminal or the access point 11 or both can be mounted on a memory card. FIG. 37 shows an example in which the wireless communication device is mounted on a memory card. The memory card 331 includes a wireless communication device 355 and a memory card main body 332. The memory card 331 uses the wireless communication device 335 for wireless communication with an external device (the wireless terminal and / or the access point 11 or both). In FIG. 37, other elements (for example, a memory) in the memory card 331 are omitted.

(Fifth embodiment)
In the fifth embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both of them), the bus , A processor unit, and an external interface unit. The processor and the external interface are connected to an external memory (buffer) via a bus. Firmware operates in the processor unit. As described above, by including the firmware in the wireless communication device, the function of the wireless communication device can be easily changed by rewriting the firmware. The processor unit on which the firmware operates may be the control unit according to the present embodiment or a processor that performs processing of the control unit, or may be another processor that performs processing related to function expansion or change of the processing. Good. The access point, the wireless terminal, or both of them may include a processor unit on which firmware operates. Alternatively, the integrated circuit in the wireless communication device mounted on the access point or the integrated circuit in the wireless communication device mounted on the wireless terminal may include the processor unit.

(Sixth embodiment)
In the sixth embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both of them), the clock A generating unit. The clock generation unit generates a clock and outputs the clock to the outside of the wireless communication device from an output terminal. Thus, by outputting the clock generated inside the wireless communication device to the outside and operating the host with the clock output to the outside, the host and the wireless communication device can be operated in synchronization with each other. It becomes possible.

(Seventh embodiment)
In the seventh embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both of them), a power supply Unit, a power control unit, and a wireless power supply unit. The power control unit is connected to the power supply unit and the wireless power supply unit, and performs control for selecting power to be supplied to the wireless communication device. In this manner, by providing a power supply in the wireless communication device, a power-saving operation in which the power supply is controlled can be performed.

(Eighth embodiment)
The eighth embodiment includes a SIM card in addition to the configuration of the wireless communication device according to the seventh embodiment. The SIM card is connected to the transmission unit (102 or 202) or the reception unit (103 or 203) or the control unit (101 or 201) or a plurality of these units in the wireless communication device. As described above, by providing the SIM card in the wireless communication device, the authentication process can be easily performed.

(Ninth embodiment)
The ninth embodiment includes a moving image compression / decompression unit in addition to the configuration of the wireless communication device according to the fifth embodiment. The moving image compression / decompression unit is connected to the bus. As described above, by providing the moving image compression / decompression unit in the wireless communication device, transmission of the compressed moving image and expansion of the received compressed moving image can be easily performed.

(Tenth embodiment)
In the tenth embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both of them), Including parts. The LED unit is connected to the transmitting unit (102 or 202), the receiving unit (103 or 203), the control unit (101 or 201), or a plurality of these units. As described above, by providing the wireless communication device with the LED unit, it is possible to easily notify the user of the operation state of the wireless communication device.

(Eleventh embodiment)
In the eleventh embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both), a vibrator is provided. Including parts. The vibrator unit is connected to the transmission unit (102 or 202), the reception unit (103 or 203), the control unit (101 or 201), or a plurality of these units. As described above, by providing the vibrator unit in the wireless communication device, it is possible to easily notify the user of the operation state of the wireless communication device.

(Twelfth embodiment)
In the twelfth embodiment, in addition to the configuration of the wireless communication device according to any one of the first to fourth embodiments (the wireless communication device of the access point or the wireless communication device of the wireless terminal, or both of them), a display including. The display may be connected to the control unit (101 or 201) of the wireless communication device via a bus (not shown). With the configuration including the display as described above, by displaying the operation state of the wireless communication device on the display, it is possible to easily notify the user of the operation state of the wireless communication device.

(Thirteenth embodiment)
In this embodiment, [1] a frame type in a wireless communication system, [2] a method of disconnection between wireless communication devices, [3] an access method of a wireless LAN system, and [4] a frame interval of a wireless LAN will be described.
[1] Frame Type in Communication System Generally, frames handled on a wireless access protocol in a wireless communication system are roughly classified into three types: a data frame, a management frame, and a control frame. These types are usually indicated by a header section commonly provided between frames. As a display method of the frame type, three types may be distinguished by one field, or a combination of two fields may be distinguished.

  The management frame is a frame used for managing a physical communication link with another wireless communication device. For example, there are a frame used for setting communication with another wireless communication device, a frame for releasing a communication link (that is, disconnecting a connection), and a frame related to a power saving operation in the wireless communication device. .

  The data frame is a frame for transmitting data generated inside the wireless communication device to another wireless communication device after a physical communication link has been established with another wireless communication device. The data is generated in a higher layer of the present embodiment, and is generated by, for example, a user operation.

  The control frame is a frame used for control when transmitting / receiving (exchanging) a data frame with another wireless communication device. When the wireless communication device receives a data frame or a management frame, a response frame transmitted to confirm delivery of the data frame or the management frame belongs to a control frame.

  These three types of frames are transmitted through the antenna as physical packets through necessary processing in the physical layer. In the connection establishment procedure, the connection request frame and the connection acceptance frame are management frames, and the confirmation frame for the connection acceptance frame can use a response frame of the control frame.

[2] Method of Disconnecting Connection between Wireless Communication Devices There are an explicit method and an implicit method for disconnecting a connection. As an explicit method, one of the connected wireless communication devices transmits a frame for disconnection. This frame is classified as a management frame. A frame for disconnection may be referred to as a release frame, for example, to release a connection. Normally, the wireless communication device that transmits the release frame determines that the connection has been disconnected when the release frame is transmitted, and the wireless communication device that receives the release frame receives the release frame. Thereafter, the process returns to the initial state in the communication phase, for example, a state of searching for a wireless communication device of a communication partner. This is because when transmitting a frame for disconnection, a physical wireless link may not be able to be secured, for example, a communication distance between the wireless communication device and a wireless signal becomes unreceivable or undecodable. Because.

  On the other hand, as an implicit method, a frame transmission (transmission of a data frame and a management frame, or transmission of a response frame to a frame transmitted by the own terminal) is detected from a wireless communication device of a connection partner that has established a connection for a certain period of time. If there is no connection, the connection state is determined to be disconnected. Such a technique exists because, in the situation where the disconnection is determined as described above, the communication distance with the wireless communication apparatus to which the wireless communication apparatus is connected is so large that the wireless signal cannot be received or decoded. This is because a state in which a wireless link cannot be secured is considered. That is, the reception of the release frame cannot be expected.

  As a specific example of determining the disconnection by an implicit method, a timer is used. For example, when transmitting a data frame requesting an acknowledgment frame, a first timer (for example, a retransmission timer for a data frame) that limits the retransmission period of the frame is started, and the first timer expires (that is, the first timer expires). If no acknowledgment frame for the frame is received (until the desired retransmission period elapses), retransmission is performed. When receiving the acknowledgment frame for the frame, the first timer is stopped.

  On the other hand, if the first timer expires without receiving the acknowledgment frame, for example, it is determined whether the wireless communication device to be connected still exists (within the communication range) (in other words, whether the wireless link has been secured). A management frame is transmitted, and at the same time, a second timer (for example, a retransmission timer for a management frame) for limiting the retransmission period of the frame is started. Similarly to the first timer, the second timer performs retransmission unless the acknowledgment frame for the frame is received until the second timer expires, and determines that the connection has been disconnected when the second timer expires. .

  Alternatively, when a frame is received from the wireless communication device of the connection partner, the third timer is started, and every time a frame is newly received from the wireless communication device of the connection partner, the third timer is stopped and restarted from the initial value. When the third timer expires, a management frame for confirming whether the wireless communication device of the connection partner is still present (within the communication range) (in other words, whether a wireless link has been secured) is transmitted as described above. At the same time, a second timer (for example, a management frame retransmission timer) for limiting the retransmission period of the frame is started. Also in this case, if the acknowledgment frame for the frame is not received until the second timer expires, retransmission is performed, and if the second timer expires, the connection is determined to be disconnected. The latter management frame for confirming whether the wireless communication device of the connection partner still exists may be different from the management frame in the former case. In this case, the timer for restricting retransmission of the management frame in the latter case is the same as the second timer here as the second timer, but a different timer may be used.

[3] Access method of wireless LAN system For example, there is a wireless LAN system that is assumed to communicate or compete with a plurality of wireless communication devices. In an IEEE802.11 (including extended standard) wireless LAN, CSMA / CA is the basis of an access method. In a system in which transmission from a certain wireless communication device is grasped and transmission is performed at a fixed time after the end of the transmission, transmission is simultaneously performed by a plurality of wireless communication devices grasping the transmission of the wireless communication device. The frame transmission fails due to collision of radio signals. By grasping the transmission of a certain wireless communication device and waiting for a random time from the end of the transmission, the transmissions of the plurality of wireless communication devices that grasped the transmission of the wireless communication device are stochastically dispersed. Therefore, if only one wireless communication device subtracts the earliest time from the random time, frame transmission by the wireless communication device succeeds, and it is possible to prevent frame collision. Since the acquisition of the transmission right becomes fair among a plurality of wireless communication devices based on a random value, the method employing Carrier Aviodance is said to be a method suitable for sharing a wireless medium among a plurality of wireless communication devices. be able to.

[4] Wireless LAN Frame Interval The IEEE 802.11 wireless LAN frame interval will be described. Frame interval used in IEEE802.11 wireless LAN, distributed coordination function interframe space (DIFS), arbitration interframe space (AIFS), point coordination function interframe space (PIFS), short interframe space (SIFS), extended interframe space (EIFS) , Reduced interframe space (RIFS).

  In the IEEE 802.11 wireless LAN, the definition of the frame interval is defined as a continuous period in which carrier sense idle should be confirmed and opened before transmission, and a period from a strict previous frame will not be discussed. Therefore, the description in the IEEE 802.11 wireless LAN system here follows the definition. In the IEEE802.11 wireless LAN, the time to wait for random access based on CSMA / CA is the sum of the fixed time and the random time, and it can be said that such a definition is used to clarify the fixed time.

  DIFS and AIFS are frame intervals used when trying to start frame exchange during a contention period competing with another wireless communication device based on CSMA / CA. The DIFS is used when there is no distinction between priorities based on the traffic type, and the AIFS is used when a priority based on the traffic type (Traffic Identifier: TID) is provided.

  Since operations related to DIFS and AIFS are similar, the following description will be made mainly using AIFS. In the IEEE 802.11 wireless LAN, access control including the start of frame exchange is performed in the MAC layer. Further, when QoS (Quality of Service) is supported when data is passed from the upper layer, a traffic type is notified together with the data, and the data is classified according to the priority at the time of access based on the traffic type. The class at the time of this access is called an access category (Access Category; AC). Therefore, an AIFS value is provided for each access category.

  PIFS is a frame interval for enabling access having priority over other competing wireless communication devices, and has a shorter period than any of the values of DIFS and AIFS. SIFS is a frame interval that can be used when transmitting a control frame for a response system or when frame exchange is continued in a burst after acquiring an access right once. EIFS is a frame interval that is activated when the frame reception fails.

  RIFS is a frame interval that can be used when a plurality of frames are continuously transmitted to the same wireless communication device in a burst after the access right is once obtained. Does not request a response frame.

  FIG. 38 shows an example of frame exchange during a contention period based on random access in an IEEE 802.11 wireless LAN.

  It is assumed that when a transmission request for a data frame (W_DATA1) occurs in a certain wireless communication apparatus, the medium is recognized as a busy medium as a result of carrier sense. In this case, an AIFS is provided for a fixed time from the time when the carrier sense becomes idle, and thereafter, when a random time (random backoff) is provided, the data frame W_DATA1 is transmitted to the communication partner.

  The random time is obtained by multiplying a slot time by a pseudorandom integer derived from a uniform distribution during a contention window (CW) given as an integer from 0. Here, the value obtained by multiplying the slot time by the CW is called a CW time width. The initial value of CW is given by CWmin, and every time retransmission is performed, the value of CW is increased until it becomes CWmax. Both CWmin and CWmax have values for each access category, similar to AIFS. When the wireless communication apparatus at the transmission destination of W_DATA1 succeeds in receiving the data frame, it transmits a response frame (W_ACK1) after SIFS from the end of the reception of the data frame. Upon receiving W_ACK1, the wireless communication device that has transmitted W_DATA1 can transmit the next frame (for example, W_DATA2) after the SIFS within the transmission burst time limit.

  AIFS, DIFS, PIFS, and EIFS are functions of SIFS and slot time, and SIFS and slot time are defined for each physical layer. Also, parameters for which values are provided for each access category such as AIFS, CWmin, and CWmax can be set for each communication group (Basic Service Set (BSS) in IEEE 802.11 wireless LAN), but default values are defined. .

  For example, in the standardization of 802.11ac, the SIFS is 16 μs and the slot time is 9 μs, whereby the PIFS is 25 μs, the DIFS is 34 μs. BEST EFFORT (AC_BE) frame interval has a default value of 43 μs, VIDEO (AC_VI) and VOICE (AC_VO) frame interval has a default value of 34 μs, and CWmin and CWmax have default values of 31 and 1023 for AC_BK and AC_BE, respectively. , 15 for AC_VI and 7 and 15 for AC_VO. The EIFS is the sum of the SIFS, the DIFS, and the time length of the response frame when transmitting at the lowest required physical rate. In the present embodiment, a wireless communication system using such a parameter of the frame interval is assumed as an interference system having a wide communication range.

(14th embodiment)
FIG. 39 is a functional block diagram of an access point 400 according to the fourteenth embodiment. This access point includes a communication processing unit 401, a transmission unit 402, a reception unit 403, antennas 42A, 42B, 42C, 42D, a network processing unit 404, a wired I / F 405, and a memory 406. . The access point 400 is connected to the server 407 via a wired I / F 405. The communication processing unit 401, the transmission unit 402, and the reception unit 403 have the same functions as the control unit 101, the transmission unit 102, and the reception unit 103 described in the first embodiment, respectively. Here, the communication processing unit 401 may internally have a buffer for transferring data with the network processing unit 404. This buffer may be a volatile memory such as a DRAM or a nonvolatile memory such as a NAND or MRAM.

  The network processing unit 404 controls data exchange with the communication processing unit 401, data writing / reading with the memory 406, and communication with the server 407 via the wired I / F 405. The network processing unit 404 may perform communication processing above the MAC layer, such as TCP / IP and UDP / IP, and processing of the application layer. The operation of the network processing unit may be performed by processing of software (program) by a processor such as a CPU, may be performed by hardware, or may be performed by both software and hardware.

  As an example, the communication processing unit 401 corresponds to a baseband integrated circuit, and the transmitting unit 402 and the receiving unit 403 correspond to an RF integrated circuit that transmits and receives frames. The communication processing unit 401 and the network processing unit 404 may be configured by one integrated circuit (one chip). Further, the communication processing unit 401 may execute a higher-layer communication process of the MAC layer such as TCP / IP or UDP / IP. Although the number of antennas is four here, it is sufficient that at least one antenna is provided.

  The memory 406 stores data received from the server 407, data received by the receiving unit 402, and the like. The memory 406 may be, for example, a volatile memory such as a DRAM or a nonvolatile memory such as a NAND or an MRAM. Further, an SSD, HDD, SD card, eMMC, or the like may be used. The memory 406 may be external to the access point 400.

  The wired I / F 405 transmits and receives data to and from the server 407. In the present embodiment, communication with the server 407 is performed by wire, but communication with the server 407 may be performed wirelessly.

  The server 407 is a communication device that receives a data transfer request for requesting data transmission and returns a response including the requested data. For example, an HTTP server (Web server), an FTP server, or the like is assumed. However, the present invention is not limited to this as long as it has a function of returning requested data. A communication device such as a PC or a smartphone operated by a user may be used. In addition, it may communicate with the access point 400 wirelessly.

  When the STA belonging to the BSS of the access point 400 issues a data transfer request to the server 407, a packet related to the data transfer request is transmitted to the access point 400. The access point 400 receives the packet via the antennas 42A to 42D, and executes processing of the physical layer by the receiving unit 403 and processing of the MAC layer by the communication processing unit 401.

  The network processing unit 404 analyzes the packet received from the communication processing unit 401. Specifically, a destination IP address, a destination port number, and the like are confirmed. If the data of the packet is a data transfer request such as an HTTP GET request, the network processing unit 404 stores the data requested by the data transfer request (for example, the data existing in the URL requested by the HTTP GET request) It is checked whether the data is cached in the memory 406. Here, the fact that the data is cached in the memory 406 is expressed as the presence of cache data in the memory 406.

  If no cache data exists in the memory 406, the network processing unit 404 transmits a data transfer request to the server 407 via the wired I / F 405. That is, the network processing unit 404 transmits a data transfer request to the server 407 on behalf of the STA. Specifically, the network processing unit 404 generates an HTTP request, performs a protocol process such as adding a TCP / IP header, and passes the packet to the wired I / F 405. The wired I / F 405 transmits the received packet to the server 407.

  The wired I / F 405 receives from the server 407 a packet that is a response to the data transfer request. The network processing unit 404 recognizes from the IP header of the packet received via the wired I / F 405 that the packet is addressed to the STA, and passes the packet to the communication processing unit 401. The communication processing unit 401 executes the processing of the MAC layer for the packet, and the transmission unit 402 executes the processing of the physical layer, and transmits the packet addressed to the STA from the antennas 42A to 42D. Here, the network processing unit 404 stores the data received from the server 407 in the memory 406 as cache data.

  When cache data exists in the memory 406, the network processing unit 404 reads the data requested by the data transfer request from the memory 406, and transmits the data to the communication processing unit 401. Specifically, an HTTP header or the like is added to the data read from the memory 406, a protocol process such as addition of a TCP / IP header is performed, and the packet is transmitted to the communication processing unit 401. At this time, as an example, the source IP address of the packet is set to the same IP address as the server, and the source port number is set to the same port number as the server (the destination port number of the packet transmitted by the communication terminal). Therefore, from the STA's point of view, it looks as if they are communicating with the server 407. The communication processing unit 401 executes processing of the MAC layer for the packet, and the transmission unit 402 executes processing of the physical layer, and transmits a packet addressed to the STA from the antennas 42A to 42D.

  With such an operation, frequently accessed data responds based on the cache data stored in the memory 406, and traffic between the server 407 and the access point 400 can be reduced. Note that the operation of the network processing unit 404 is not limited to the operation of the present embodiment. A general cache proxy that obtains data from the server 407 instead of the STA, caches the data in the memory 406, and responds to a data transfer request for the same data from the cache data in the memory 406. There is no problem with another operation.

  In the present embodiment, an access point having a cache function has been described. However, by adding a network processing unit 404, a wired I / F 405, and a memory 406 to the configuration shown in FIG. An STA having a function can also be realized. The data exchange between the access point and the STA described in the above-described embodiment can be realized by using the cache function described in the present embodiment.

  In the above-described embodiment, the embodiment in which the address information is used as the identifier for determining whether the received frame is a unicast, a multicast, or a broadcast has been disclosed. However, the present invention is not limited to this. For example, a form in which the identification is performed using the number of AID fields included in the received frame as identification information other than the address information is also possible. In this case, it can be determined that unicast transmission is performed when there is one AID field, and that multicast transmission or broadcast transmission is performed when there are multiple AID fields.

  Note that the frame described in each embodiment may refer to a packet called a packet in the IEEE 802.11 standard or a compliant standard such as Null Data Packet.

  The terms used in this embodiment should be interpreted broadly. For example, the term “processor” may include a general purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, and the like. In some circumstances, "processor" may refer to an application specific integrated circuit, a field programmable gate array (FPGA), a programmable logic circuit (PLD), and the like. “Processor” may refer to a combination of processing devices, such as a plurality of microprocessors, a combination of a DSP and a microprocessor, or one or more microprocessors cooperating with a DSP core.

  As another example, the term “memory” may encompass any electronic component capable of storing electronic information. “Memory” includes random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable PROM (EEPROM), and non-volatile It may refer to random access memory (NVRAM), flash memory, magnetic or optical data storage, which are readable by a processor. If a processor reads and / or writes information to and from a memory, then the memory can be said to be in electrical communication with the processor. The memory may be integrated with the processor, and again, the memory may be said to be in electrical communication with the processor.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.

11: Access point (base station, wireless terminal)
12A, 12B, 12C, 12D: Antennas 1, 2, 3, 4, 5, 6, 7, 8: Wireless terminal 1A: Antenna 501: Trigger frames 541 to 545: Delivery confirmation response frame (BA frame)
551: Multi-STA BA frames 561-564: Aggregation frame 565: BA frames 571, 572, 575: Aggregation frame 573: Multi-STA BA frame 581: Multi-STA BA frame 586, 587, 588: Data frame 591: Aggregation Frame 592: Multi-STA BA frame 597, 598: Data frame 601, 603: Multi-STA BA frame 611: BA frame 613: Multi-STA BA frame 621: Aggregation frame 101, 201: Control unit 102, 202: Transmission unit 103, 203: receiving units 104, 204: buffer 211: baseband IC
213: memory 214: host interface 215: CPU
216: DAC
217: ADC
221: RF IC
222, 232: Filter 223, 233: Mixer 224, 234: Amplifier 225, 235: Balun 242: PLL
243: crystal oscillator 247: antenna 245: switch 148: wireless LAN module 149: host system 301: notebook PC
305, 315, 355: wireless communication device 321: mobile wireless terminal 331: memory card 332: memory card body 42A, 42B, 42C, 42D: antenna 401: communication control unit 402: transmitting unit 403: receiving unit 404: network processing Unit 405: Wired I / F
406: Memory 407: Server

Claims (10)

A receiving unit that receives a plurality of multiplexed first frames, the source address being a plurality of first wireless communication devices ;
Determining a second wireless communication device that is a target for transmitting a second frame and a third wireless communication device that is not a target for transmitting the second frame among the plurality of first wireless communication devices;
One or more third frames whose destination addresses are the respective second wireless communication devices, and a fourth frame including all acknowledgments of the first frames received from the third wireless communication device. A transmission unit for multiplexing transmission,
Equipped with a,
The third frame includes the second frame and a delivery confirmation response of the first frame received from the second wireless communication device,
The receiving unit receives the plurality of first frames via a plurality of first communication resources belonging to a first frequency band,
The number of the third wireless communication devices is two or more,
The transmitting unit transmits the fourth frame using one second communication resource,
The transmitting unit transmits the one or more third frames using the same number of third communication resources as the number of the second wireless communication devices, and each of the third communication resources transmits each of the third frames. ,
The wireless communication device, wherein the second communication resource and the third communication resource belong to the first frequency band . The transmitting unit transmits, using a fourth communication resource, a fifth frame having a fourth wireless communication device different from the plurality of first wireless communication devices as a destination address,
  The fifth frame is multiplexed with the third frame and the fourth frame,
  The wireless communication device according to claim 1.   The transmitting unit transmits the fourth frame in the first frequency band when the number of the second wireless communication devices is zero.
  The wireless communication device according to claim 1. Wherein at least one of the second frame, the radio communication apparatus according to any one of claims 1 to 3 is a data frame. The wireless communication device according to any one of claims 1 to 3 , wherein at least one of the second frames includes information instructing the second wireless communication device to transmit a seventh frame.   The plurality of first frames are multiplexed using at least one of frequency multiplexing and spatial multiplexing,
  The third frame and the fourth frame are multiplexed and transmitted using at least one of frequency multiplexing and spatial multiplexing.
  The wireless communication device according to claim 1.   Further comprising at least one antenna
  The wireless communication device according to claim 1. Receiving a plurality of multiplexed first frames whose source addresses are a plurality of first wireless communication devices ;
Determining a second wireless communication device that is a target for transmitting a second frame and a third wireless communication device that is not a target for transmitting the second frame among the plurality of first wireless communication devices;
One or more third frames whose destination addresses are the respective second wireless communication devices, and a fourth frame including all acknowledgments of the first frames received from the third wireless communication device. Multiplex,
The third frame includes the second frame and a delivery acknowledgment of the first frame received from the second wireless communication device,
Receiving the plurality of first frames via a plurality of first communication resources belonging to a first frequency band;
The number of the third wireless communication devices is two or more,
Transmitting the fourth frame with one second communication resource;
Transmitting the one or more third frames using the same number of third communication resources as the number of the second wireless communication devices, each of the third communication resources transmitting each of the third frames,
The second communication resource and the third communication resource belong to the first frequency band
Wireless communication method.   A receiving unit that receives a plurality of multiplexed first frames, the source address being a plurality of first wireless communication devices;
  A transmitting unit configured to multiplex a second frame including all acknowledgments of the first frame received from the plurality of first wireless communication devices, and at least one third frame;
  With
  The destination address of the third frame is a second wireless communication device different from the plurality of first wireless communication devices,
  The receiving unit receives the plurality of first frames via a plurality of first communication resources belonging to a first frequency band,
  Transmitting the second frame with one second communication resource;
  The transmitting unit transmits each third frame using the same number of third communication resources as the number of the second wireless communication devices, and each third communication resource transmits each third frame;
  The second communication resource and the third communication resource belong to the first frequency band
  Wireless communication device. A wireless communication method performed by a wireless communication device,
Receiving a plurality of multiplexed first frames whose source addresses are a plurality of first wireless communication devices;
  Multiplexing a second frame including all acknowledgments of the first frame received from the plurality of first wireless communication devices and at least one third frame;
  The destination address of the third frame is a second wireless communication device different from the plurality of first wireless communication devices,
  Receiving the plurality of first frames via a plurality of first communication resources belonging to a first frequency band;
  Transmitting the second frame with one second communication resource;
  Transmitting each third frame using the same number of third communication resources as the number of the second wireless communication devices, each third communication resource transmitting each third frame,
  The second communication resource and the third communication resource belong to the first frequency band
  Wireless communication method.

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