JP2017092686A - Integrated circuit for radio communication, radio communication terminal and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a notification of acknowledgement to a terminal may be dropped.SOLUTION: An integrated circuit for radio communication comprises a baseband integrated circuit. The baseband integrated circuit receives a plurality of first frames via an RF integrated circuit, and inspects whether the plurality of first frames is successfully received. If reception of at least one of the plurality of first frames is failed, a bit map representing whether each of the plurality of first frames is successfully received is set in a first field. A first value is set to a second field for reporting whether the first field is present. If all receptions of the plurality of first frames are made successful, a second value is set to the second field and a second frame in which the first field is not present is transmitted via the RF integrated circuit.SELECTED DRAWING: Figure 8

Description

  Embodiments described herein relate generally to an integrated circuit for wireless communication, a wireless communication terminal, 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) that employs CSMA / CA (Carrier Sense Multiple Access / Collection Aviation) is widely known. In the next-generation wireless LAN, frequency multiplex communication in which different frequency components are assigned as communication resources for each terminal and transmission to a plurality of terminals or reception from a plurality of terminals is simultaneously studied as multiuser communication. More specifically, as frequency multiplex communication, a frequency component is defined as a resource unit including one or a plurality of orthogonal subcarriers, a resource unit is allocated to each terminal as a communication resource, and transmission to a plurality of terminals or a plurality of terminals is performed. Orthogonal frequency division multiple access (OFDMA) that simultaneously receives data from multiple terminals has been studied. Simultaneous transmission from the access point to a plurality of terminals corresponds to downlink OFDMA (DL-OFDMA), and simultaneous transmission from the plurality of terminals to the access point corresponds to uplink OFDMA (UL-OFDMA). As another example of multi-user communication, uplink MU-MIMO (UL-MU-MIMO) is also being studied. UL-OFDMA and UL-MU-MIMO are examples of uplink multi-user (UL-MU) communication.

  There has been proposed a method of transmitting a frame that collectively includes acknowledgment confirmation responses of a plurality of terminals with respect to a frame transmitted from a plurality of terminals by UL-MU. As a frame format used at this time, a Multi-STA BA frame using the Block ACK format has been proposed. Assuming that frames transmitted from a plurality of terminals are UL-MU, aggregation frames (A-MPDU) in which a plurality of data (subframes) are aggregated are assumed. In the access point, for each of the plurality of subframes of each terminal, a bitmap in which the success / failure of reception (CRC inspection result or the like) is reflected in the bits is set in the Multi-STA BA frame for each terminal. At this time, if all the subframes have been successfully received (all the CRC check results are OK), it is proposed that the bit map is omitted for the terminal and “indication flag bit” is set to 1. Yes. By detecting that “indication flag bit” is 1, the terminal side can recognize that transmission of all the transmitted data is successful even without a bitmap. By omitting the bitmap, it is possible to reduce the size of the Multi-STA BA frame and improve efficiency.

  However, this operation is assumed in the case where the Ack_Policy field of the Frame Control field of each subframe of the aggregation frame transmitted by the terminal is “00” (Implicit Block ACK). That is, it is assumed that the access point immediately returns a delivery confirmation response to the frame received from the terminal. When the terminal transmits an aggregation frame including a plurality of subframes whose Ack_Policy field is set to “11” (Explicit Block Ack), the access point delivers each subframe until receiving a Block Ack request from the terminal. Does not return an acknowledgment. If the terminal does not transmit a Block Ack request, transmits a frame set to Implicit Block ACK, and receives an indication flag bit 1 from the access point for the frame, the operation of the terminal Depending on the situation, it is possible that the transmission of the aggregation frame transmitted before the aggregation frame is mistakenly recognized as successful and the BA frame is not transmitted, so that the notification of the delivery confirmation response of the frame may be missed.

IEEE Std 802.11ac (TM) -2013 IEEE Std 802.11 (TM) -2012 IEEE802.11-15 / 03366r1 IEEE 802.11-15 / 0626r1

  The embodiment of the present invention aims to drop notification of a delivery confirmation response to a terminal.

  An integrated circuit for wireless communication as an embodiment of the present invention includes a baseband integrated circuit. The baseband integrated circuit receives a plurality of first frames via an RF integrated circuit, checks whether the plurality of first frames have been successfully received, and receives at least one of the plurality of first frames. If the first field fails, a bit map indicating whether or not each of the plurality of first frames has been successfully received is set in the first field, and the second field for notifying whether the first field exists is set in the second field. When 1 value is set and all of the plurality of first frames are successfully received, the second field is set to a second value, and the second frame without the first field is set as the RF integrated circuit. To send through.

The figure which shows the radio | wireless communications system which concerns on 1st Embodiment. The figure for demonstrating allocation of a resource unit. The figure for demonstrating the form of a resource unit. The figure for demonstrating the concept of UL-MU-MIMO. The figure which shows the schematic format example of the physical packet used by UL-MU-MIMO transmission. The figure which shows the example of a basic format of a MAC frame. The figure which shows the format example of an information element. The figure which shows the 1st example of the operation | movement sequence which concerns on 1st Embodiment. The figure for demonstrating schematic structure of a physical packet. The figure which shows the format example of the trigger frame which concerns on 1st Embodiment. The figure which shows the modification of the physical packet containing the trigger frame which concerns on 1st Embodiment. Explanatory drawing of a Multi-STA BA frame. The figure which shows the 2nd example of the operation | movement sequence which concerns on 1st Embodiment. The figure which shows the 3rd example of the operation | movement sequence which concerns on 1st Embodiment. The figure which shows the 2nd example of the operation | movement sequence which concerns on 1st Embodiment. The functional block diagram of the radio | wireless communication apparatus mounted in the access point which concerns on 1st Embodiment. The functional block diagram of the radio | wireless communication apparatus mounted in the terminal which concerns on 1st Embodiment. The figure which shows the flowchart of operation | movement of the access point which concerns on 1st Embodiment. The figure which shows the flowchart of operation | movement of the terminal which concerns on 1st Embodiment. The figure which shows the example of whole structure of the terminal or access point which concerns on 2nd Embodiment. The figure which shows the hardware structural example of the radio | wireless communication apparatus mounted in the access point or terminal which concerns on 2nd Embodiment. The perspective view of the radio | wireless terminal which concerns on 3rd Embodiment. The figure which shows the memory card based on 3rd Embodiment. The figure which shows an example of the frame exchange of a contention period.

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, known as wireless LAN standards, are all incorporated herein by reference.

(First embodiment)
FIG. 1 is a configuration diagram of a wireless communication system including an access point (AP) that is a base station according to the first embodiment and a wireless communication terminal (hereinafter referred to as a terminal). Since the access point also has basically the same function as the terminal except that it has a relay function, it can be said that the access point is also a form of the terminal. As an example, the access point and the terminal include a wireless communication device that performs communication based on 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. A configuration is also possible in which communication conforming to a communication method other than the IEEE 802.11 standard is performed between the access point and the terminal.

  Terminals (STA: STATION) 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 radio link is established, and a radio link is established by completing exchange of parameters necessary for communication through an association process with an access point. Terminals 1 to 8 belong to the BSS of the access point 11. An authentication process may be performed prior to the association process.

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

  Each terminal 1-8 includes one or more antennas. Each terminal is equipped with a wireless communication device. The wireless communication device of each terminal transmits / receives a frame to / from the access point 11 via the antenna. The wireless communication device of each terminal includes a wireless communication unit that is connected to the antenna 11 and transmits / receives a frame, and a control unit that controls communication with the access point 11 via the wireless communication unit. The wireless communication unit is formed by an RF (Radio Frequency) integrated circuit as an example, and the control unit is formed by a baseband integrated circuit as an example, but is not limited to this configuration.

  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 connected to another network (referred to as 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. The access point 11 may also relay communication between a plurality of terminals in the first network. Frames generated by the terminals 1 to 8 are transmitted to the access point 11. The access point 11 may transmit the 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 a frame referred to in the IEEE 802.11 standard, but may be referred to as a packet.

  In the present embodiment, uplink multi-user (Up-MU) communication can be performed between the access point 11 and a plurality of terminals selected from the plurality of terminals 1 to 8. Assume a certain case. For example, an uplink orthogonal frequency division multiple access (OFDMA) or uplink MU-MIMO (Multi-Input Multi-Output) is possible. Hereinafter, uplink OFDMA is described as UL-OFDMA, and uplink MU-MIMO is described as UL-MU-MIMO.

  In OFDMA, resource units including one or more subcarriers (which may be called subchannels, resource blocks, frequency blocks, etc.) are allocated to terminals as communication resources, and are simultaneously communicated with a plurality of terminals on a resource unit basis. .

  The resource unit is a frequency component that is a minimum unit of resources for communication. FIG. 2 shows resource units (RU # 1, RU # 2,... RU # K) secured in a continuous frequency region within one channel (denoted as channel M here). A plurality of subcarriers orthogonal to each other are arranged in channel M, and a plurality of resource units including one or more subcarriers are defined in channel M. One or more subcarriers (guard subcarriers) may be arranged between resource units, but guard subcarriers are not essential. Each resource unit or each subcarrier in the channel may be set with identification information for identifying the resource unit or subcarrier. The bandwidth of one channel is, for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, but is not limited thereto. A plurality of 20 MHz channels may be combined into one channel. Depending on the bandwidth, the number of subcarriers or resource units in the channel may be different. Multiple terminals simultaneously use different resource units, thereby realizing OFDMA communication.

  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 the arrangement pattern of resource units in one channel. The horizontal direction along the plane of the paper 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 that in FIG. . FIG. 3C shows an example in which resource units having three or more types of bandwidths are arranged. The resource unit (RU # 12-1, RU # 12-2) has the largest bandwidth, and the resource unit RU # 11- (L-1) has the same bandwidth and resource as the resource unit of FIG. Units (RU # K-1, RU # K) have the same bandwidth as the resource unit of FIG.

  The number of resource units used by each terminal in OFDMA is one or more, and is not limited to a specific value. When a terminal uses a plurality of resource units, a plurality of resource units that are continuous in frequency may be bonded to be used as one resource unit, or a plurality of resource units in remote locations may be used. Also good. The resource unit # 11-1 in FIG. 3B may be considered as an example of a resource unit obtained by bonding the resource units # 1 and # 2 in FIG.

  The subcarriers in one resource unit may be continuous in the frequency domain, or a resource unit may be defined from a plurality of subcarriers arranged discontinuously. The number of channels used in OFDMA is not limited to one. In addition to channel M, another channel (see channel N in FIG. 2) arranged at a position distant from the frequency domain may be used in the same manner as channel M. Resource units may be secured and resource units in both channel M and channel N may be used. The channel M and channel N may have the same or different resource unit arrangement method. As an example, the bandwidth of one channel is 20 MHz, 40 MHz, 80 MHz, 160 MHz, or the like as described above, but is not limited thereto. It is possible to use more than two channels. It is also possible to consider channel M and channel N as one channel.

  A terminal that implements OFDMA has at least a channel with a basic channel width (20 MHz channel width if an IEEE 802.11a / b / g / n / ac standard-compliant terminal is a legacy terminal) of a legacy terminal that is subject to backward compatibility. It is assumed that a physical packet including a frame can be received and decoded (including demodulation and decoding of an error correction code). Carrier sense is performed in units of basic channel width.

  The carrier sense includes CCA (Clear Channel Accession) busy / idle physical carrier sense (Physical Carrier Sense) and virtual carrier sense (Virtual Carrier Sense) based on the medium reservation time described in the received frame. Sense) may be included. A mechanism for determining that a medium is virtually busy, such as the latter, or a period during which a medium is virtually busy is called a NAV (Network Allocation Vector). Note that the carrier sense information based on CCA or NAV performed for each channel 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 may be determined as idle.

  Note that OFDMA can be channel-based OFDMA in addition to the resource unit-based OFDMA described above. The OFDMA in this case is sometimes called MU-MC (Multi-User Multi-Channel). In MU-MC, the access point assigns a plurality of channels (one channel width is, for example, 20 MHz) to a plurality of terminals, and simultaneously uses the plurality of channels to simultaneously transmit to or receive from a plurality of terminals. 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 the resource unit described below with a channel.

  UL-MU-MIMO is intended to increase the efficiency of uplink transmission by transmitting a frame to an access point (spatial multiplexing transmission) in the same frequency band at a plurality of terminals at the same timing. FIG. 4 is a diagram for explaining the concept of MU-MIMO. It is assumed that the access point 11 performs UL-MU-MIMO with four terminals 1 to 4 (indicated as STA1 to 4 in the figure). The terminals 1 to 4 transmit frames simultaneously using the same channel (bandwidth may be arbitrary such as 20 MHz, 40 MHz, and 80 MHz). The access point receives these frames simultaneously, but these frames can be separated using a preamble signal included in the physical header of each frame. This will be described in detail below.

  The access point 11 receives the signals of the terminals transmitted by UL-MU-MIMO as signals superimposed at the same time. In UL-MU-MIMO, the access point needs to spatially separate the frames of each terminal from signals received simultaneously from a plurality of terminals. For this purpose, the access point 11 uses an uplink channel response with each of a plurality of terminals. The access point can estimate the uplink channel response of each terminal by using a preamble signal added to the head side of a frame transmitted by a plurality of terminals. Specifically, this preamble signal is included in a field for a preamble signal in a physical header arranged on the head side of the frame. FIG. 5 shows an example of a configuration of a physical packet including a frame transmitted from the terminals 1 to 4. As shown in FIG. 5, the preamble signal is arranged in a preamble signal field between the L-SIG field and the frame, for example. The preamble signals 1 to 4 of the terminals 1 to 4 are orthogonal to each other. Note that L-STF (Legacy-Short Training Field), L-LTF (Legacy-Long Training Field), L-SIG (Legacy Signal Field), etc. arranged before the preamble signals 1 to 4 are, for example, 1 IE80 Are fields that can be recognized by legacy standard terminals, and store information such as signal detection, frequency correction (propagation estimation), and transmission speed, respectively. L-STF, L-LTF, and L-SIG are the same signals in a plurality of terminals that perform UL-MU-MIMO transmission. The above preamble signal corresponds to an example of communication resources according to the present embodiment. Hereinafter, the preamble signal will be described.

  The preamble signal is composed of a known bit string or a known symbol string. The access point 11 can correctly spatially separate (decode) the field after the preamble signal by estimating the uplink channel response using the known bit string. This can be performed using a known method such as a ZF (Zero-Forcing) method, a MMSE (Minimum Mean Square Error) method, or a maximum likelihood estimation method. For example, the preamble signal is arranged in a physical header (PHY header) arranged on the head side of the MAC frame. Since the same signal is transmitted from each terminal in the field before the preamble signal in the physical header, the access point can be decoded even if these signals are received simultaneously. On the other hand, the preamble signals of each terminal are orthogonal to each other. For this reason, the access point 11 can individually identify the preamble signals received simultaneously from the respective terminals. Thereby, the access point 11 can estimate the uplink propagation path from each terminal to the access point 11 using the preamble signal for each terminal. After the preamble signal, a separate signal is sent for each terminal, but these signals can be separated using the estimated propagation path response.

  As a method for orthogonalizing preamble signals between terminals, any of temporal, frequency, and coding methods can be used. In the case of time orthogonality, the preamble signal field is divided into a plurality of sections, and the preamble signal of each terminal is transmitted in a different section. Only one terminal transmits a preamble signal in a certain section. That is, while a certain terminal transmits a preamble signal, there is a period during which no other terminal transmits anything. In the case of frequency orthogonality, each terminal transmits a preamble signal at a frequency that is orthogonal to each other. In the case of code orthogonality, each terminal transmits a signal in which value strings (more specifically, symbol strings corresponding to the value strings) 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. In any orthogonal method, the access point 11 can identify the preamble signal of each terminal.

  In order for each terminal to use the preamble signals orthogonal to each other, the access point needs to give information on the preamble signal used by each terminal and its transmission method. Specifically, in the case of time orthogonality , At which timing the preamble signal (the preamble signal may be the same or different between the terminals) is transmitted, or in the case of frequency orthogonality, at which frequency the preamble signal (the preamble signal may be the same between the terminals) Information may be transmitted about which encoding pattern (which row or column pattern of the orthogonal matrix) is used to transmit the preamble signal in the case of code orthogonality. .

  Moreover, you may perform the system (UL-MU-MIMO & OFDMA) which combined UL-MU-MIMO and UL-OFDMA as UL-MU communication. UL-OFDMA & MU-MIMO performs MU-MIMO transmission for each resource unit by using the same resource unit among a plurality of terminals.

  In this embodiment, as described above, it is assumed that UL-MU communication is possible, but in addition to this, downlink multi-user (DL-MU) communication may be possible. For example, downlink OFDMA or downlink MU-MIMO (DL-MU-MIMO) may be feasible. DL-MU-MIMO uses a technique called beam forming to form spatially orthogonal beams for a plurality of terminals and perform frame transmission. For beam forming, the downlink channel response with each terminal is used. For this purpose, for example, the access point transmits a sounding frame (for example, a null data packet) to each terminal in advance and receives feedback of a downlink channel response measured by the terminal. Thereby, the downlink channel response of each terminal is acquired. A known technique may be used to form a beam with each terminal using the propagation path response. For example, the transmission signal to the terminal is weighted for each antenna, and the weighted transmission signal is transmitted from each antenna. This is performed for each of a plurality of terminals, and signals for the antennas of the plurality of terminals are transmitted simultaneously. For each terminal, the transmission signal is weighted so that the transmission signal is properly received by the terminal and the null signal is received (that is, the transmission signal is not received) by other terminals. DL-MU-MIMO is defined in the IEEE802.11ac standard and may be used. Moreover, you may perform the system (DL-MU-MIMO & OFDMA) which combined DL-MU-MIMO and DL-OFDMA as DL-MU communication. DL-OFDMA & MU-MIMO divides (groups) a plurality of terminals into a plurality of groups, forms a beam for each group, and performs DL-OFDMA communication with a plurality of terminals belonging to the group.

  FIG. 6A shows a basic format example of a MAC frame. The data frame, management frame, and control frame according to the present embodiment are based on such a frame format. Here, the management frame is a frame used for management of a communication link with another terminal. The data frame is a frame used for transmitting data to the other terminal in a state where a communication link is established with the other terminal. The control frame is a frame used for control when the management frame and the data frame are transmitted / received (exchanged) with another wireless communication apparatus. Details of each frame type will be described in an embodiment described later.

  The frame format of FIG. 6A includes fields of a MAC header (MAC header), a frame body (Frame body), and an FCS. 6B, each field of Frame Control, Duration / ID, Address1, Address2, Address3, Sequence Control, QoS Control, and HT (High Throughput) control is included in the MAC header.

  All of these fields do not necessarily exist, and some fields may not exist depending on the type of frame. For example, the Address3 field may not exist. In addition, there may be cases where both or one of the QoS Control and HT Control fields does not exist. There may also be no frame body field. On the other hand, other fields not shown in FIG. 6B may exist. For example, an Address4 field may further exist. In the trigger frame according to the present embodiment, a common information field and a terminal information field may exist as described later.

  The Address 1 field contains the recipient address (Receiver Address; RA), the Address 2 field contains the source address (Transmitter Address; TA), and the Address 3 field contains the BSS identifier according to the use of the frame. BSSID (Basic Service Set IDentifier) or TA is entered. The BSSID may be a wildcard BSSID (all bits are 1) for all BSSIDs.

  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 fine classification in the roughly classified frames is performed in the Subtype field. For example, the control frame includes a frame such as a BA frame, a BAR frame, and an ACK frame, and the management frame includes an association request frame, a beacon frame, and the like. These frames are identified in the Subtype field. Trigger frames described later may also be distinguished by a combination of type and subtype. The trigger frame is classified as a control frame (type is “control”) as an example, but is not limited thereto. A new value may be defined as Subtype for the trigger frame.

  The Duration / ID field describes the medium reservation time. 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 a medium is busy, or a period during which a medium is virtually busy, is referred to as NAV (Network Allocation Vector) as described above. The QoS field is used for performing QoS control in which transmission is performed in consideration of frame priority. 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. 7, the information element has an Element ID field, a Length field, and an information (Information) field. The information element is identified by an Element ID. The information field stores the content of information to be notified, and the Length field stores length information of the information field.

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

  FIG. 8 shows a first example of an operation sequence performed between the access point 11 according to the present embodiment and the terminals 1 and 2. The access point 11 repeatedly performs UL-OFDMA communication with the terminals 1 and 2 by repeating transmission of a trigger frame that induces OFDMA uplink transmission to the terminals 1 and 2.

  In this system, as a premise, communication (single user communication) is performed individually on a CSMA / CA basis between the access point and some or all of the terminals 1 to 8. 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, an access right to a wireless medium is acquired according to CSMA / CA. For this reason, the terminal performs carrier sense during the carrier sense time (waiting time) between the DIFS (Distributed Coordination Function Frame Space) / AIFS (Arbitration InterFrame Space) time and the randomly determined backoff time. ) Is determined to be idle, for example, an access right to transmit one frame is acquired. DIFS / AIFS means either DIFS or AIFS. When it is not compatible with QoS, it indicates DIFS, and when it is compatible with QoS, it indicates AIFS determined according to the access category (AC) of data to be transmitted. The DIFS time or the AIFS time is an example, and may be another time as long as it is a predetermined time. The same applies to the DIFS time and AIFS time described elsewhere in this specification.

  The terminal that has acquired the access right transmits a data frame including data to be transmitted (more specifically, a physical packet including the data frame). When the access point normally receives the data frame, the terminal receives SIFS from completion of reception of the data frame. After (Short InterFrame Space) time, an ACK frame (more specifically, a physical packet including an ACK frame) which is a delivery confirmation response frame is returned. By receiving the ACK frame, the terminal determines that the data frame has been successfully transmitted. The basic configuration of the physical packet is obtained by adding a physical header to the MAC frame stored in the data field, as shown in FIG. 9 described later. The SIFS time is an example, and other time may be used as long as it is a predetermined time. The same applies to SIFS times described elsewhere in this specification.

  The data frame to be transmitted to the access point may be an aggregation frame obtained by aggregating a plurality of frames (A-MPDU (MAC) protocol data unit, etc.). In this case, a delivery confirmation response frame to which the access point responds May be a BA (Block Ack) frame (the same applies hereinafter). Individual frames included in the aggregation frame may be referred to as subframes.

  The access point determines the start of UL-OFDMA at a predetermined timing or at an arbitrary timing. As an example, the predetermined timing may be a timing at which an uplink transmission request is received from at least one or a predetermined number of terminals, a timing at which a predetermined time arrives, or another timing. In this example, it is assumed that UL-OFDMA transmission is performed on the same channel (single channel with a basic channel width of 20 MHz) as single user communication. That is, it is assumed that UL-OFDMA transmission 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 UL-OFDMA transmission with other channel widths such as 40 MHz and 80 MHz.

  When the access point determines the start of UL-OFDMA, the access point selects a UL-OFDMA target terminal, and generates and transmits a UL-OFDMA trigger frame (more specifically, a physical packet including the trigger frame) 501.

  FIG. 10 shows a format example of the trigger frame. It is based on the general MAC frame format shown in FIG. 6, and includes a Frame Control field, a Duration / ID field, an Address1 field, an Address2 field, a common information field (Common Info.) Field, and a plurality of terminal information (STA Info). .) Field and FCS field.

  The frame is designated as a trigger frame by Type and Subtype in the Frame Control field. Type is “control” as an example, and Subtype may define a new value corresponding to the trigger frame. However, a trigger frame in which Type is “management” or “data” may be defined. Instead of defining a new value as Subtype, a field for notifying that it is a trigger frame may be expressed using a reserved field such as a MAC header.

  In the Address 1 field, a broadcast address or a multicast address may be set as RA. The MAC address (BSSID) of the access point may be set as TA in the Address2 field. However, the Address1 field, the Address2 field, or both of them may be omitted.

  In the common information field, information that is commonly notified to a plurality of terminals that are targets of UL-OFDMA is set. For example, information specifying the format of the terminal information field, information indicating the purpose of the trigger frame, information specifying the packet length (PPDU length) transmitted in the response, and information specifying the type of frame transmitted in the response Good. Information specifying a communication method (OFDMA or MU-MIMO or the like) used in UL-MU may be set. The PPDU is a physical layer convergence procedure (PLCP) protocol data unit. Instead of the PPDU length, the MAC frame length or the MSDU (medium access control (MAC) service data unit) length may be used. Further, information on the number of terminal information fields may be set in the common information field. In addition, when the access point manages the terminals belonging to the BSS divided into groups and selects a plurality of terminals that are the targets of UL-OFDMA from the same group, or all the terminals in the group are the targets of the UL-OFDMA. In that case, an identifier (group ID) of a group to which these terminals belong may be set. The group ID may be the same as the group ID defined by IEEE802.11ac, or may be defined separately. Note that terminals belonging to the BSS receive a list of terminals and group IDs from an access point in advance via a management frame or the like.

  In the terminal information fields 1 to n, information to be notified to individual terminals that are targets of UL-MU (here, UL-OFDMA) is set. For example, information specifying a terminal that is a target of UL-OFDMA and information specifying a resource unit to be allocated to the terminal are set. The information for designating the terminal may be an association ID (AID), a part of AID (Partial AID), a MAC address, or other values. The association ID is an identifier given at the time of the association process performed with the access point because the terminal belongs to the BSS of the access point. The information specifying the resource unit may be an identifier of the resource unit. When a plurality of resource units continuous in the frequency domain are specified, the range of the resource unit may be specified. The number of the resource unit from the high frequency side or the low frequency side in the channel to be used may be specified. A configuration is also conceivable in which an identifier for identifying a set of a plurality of resource units is defined and one or a plurality of the identifiers are designated. In this case, the terminal can grasp a plurality of resource units from the identifier.

  In the terminal information fields 1 to n, information specifying transmission power and information specifying an adjustment amount of transmission timing with respect to a timing specified in advance may be set. For this reason, the access point may determine in advance transmission power such that reception power (RSSI or the like) received from each terminal is within the same or constant range. Regardless of the distance to the terminal or the radio wave environment, the access point measures the transmission timing difference of each terminal in advance so that signals transmitted from multiple terminals can be received simultaneously, and adjusts the transmission timing of each terminal. The amount may be determined. Information other than that described here may be set in the common information field and the terminal information field.

  When UL-MU-MIMO is performed as UL-MU communication, information for identifying a preamble signal included in a physical header of a packet to be transmitted instead of information designating a resource unit in the terminal information field, and a preamble signal transmission method Information for specifying (transmission frequency or transmission time) may be set.

  In this sequence example, it is assumed that the access point has selected terminal 1 and terminal 2 as UL-OFDMA targets. The method for selecting the terminal may be arbitrary. For example, the terminal may be selected from terminals that have previously notified the presence of an uplink transmission request. Alternatively, based on the transmission data amount (data size) possessed by each terminal, the terminal having the largest data amount may be preferentially selected. Alternatively, terminals with the same amount of data may be selected. Alternatively, the terminal may be selected by round robin. Alternatively, it is possible to select terminals having the same data generation cycle or a similar generation cycle (terminals whose generation cycle is included within a certain value, or a predetermined number of terminals having the closest generation cycle). Further, terminals having the same type of data to be transmitted may be selected. The data type may be AC (Access Category) when QoS is supported. The data type may be TID (Traffic ID). When the lower limit of the number of terminals to be selected is determined, the number of terminals equal to or higher than the lower limit may be selected. The terminal selection example described here is merely an example, and the terminal may be selected by a method other than the method described here.

  The access point determines resource units to be assigned to the selected terminal 1 and terminal 2, and other parameter information (transmission power, etc.) as necessary. Information that needs to be individually notified to the terminal 1 and the terminal 2 such as information specifying the terminals 1 and 2, the determined resource unit and other parameter information is set in the terminal information fields 1 and 2. In addition, if there is necessary information to be commonly notified to the terminals 1 and 2 in the common information field, it is set. For example, information specifying the format of the terminal information field, information indicating the purpose of the trigger frame, information specifying the transmission packet length, information specifying the type of frame to be transmitted, and the like may be set.

  When the access point sets the necessary information in the common information field and the terminal information fields 1 and 2 to generate the trigger frame 501, for example, based on the access right to the wireless medium acquired according to CSMA / CA, the access point Specifically, a physical packet including a trigger frame is transmitted. As an example, the trigger frame 501 is transmitted using a channel having the same basic channel width (20 MHz) 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 shown in FIG. 9, the physical header includes L-STF (Legacy-Short Training Field), L-LTF (Legacy-Long Training Field), L-SIG (Legacy Signal) defined in the IEEE 802.11 standard. Field). A set of L-STF, L-LTF, and L-SIG may be referred to as a legacy preamble. L-STF, L-LTF, and L-SIG are fields that can be recognized by terminals of legacy standards such as IEEE802.11a, for example, and include information such as signal detection, frequency correction (channel propagation estimation), and transmission speed, respectively. Stored. Fields other than those described here (for example, a field in which a legacy terminal cannot be recognized and an OFDMA-compatible terminal can be recognized) may be included. The trigger frame 501 may be a frame that can be received and decoded by legacy terminals as well as UL-OFDMA compatible terminals. Note that “...” In FIG. 9 means that a field other than that shown in the figure may or may not exist.

  As shown in FIG. 11, the common information field and the terminal information field may be arranged in the physical header instead of the MAC frame. In this case, the trigger frame may be a frame without a frame body field. One of the common information field and the terminal information field may be arranged in the physical header and the other one in the trigger frame.

  Here, the frame control field type of the trigger frame may be a value representing a control frame, and the subtype value 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. A common information field and a terminal information field may be added as information elements to the frame body field of an existing management frame. RA (reception destination address) is, for example, a broadcast address or a multicast address, and the address may be set in the address 1 field. For the TA (source address), the MAC address or BSSID of the access point may be set in the address 2 field. A configuration in which one or both of the address 1 field and the address 2 field are omitted is also possible.

  When the terminal that has received the trigger frame 501 (more specifically, the physical packet including the trigger frame 501) transmitted from the access point succeeds in receiving the trigger frame 501, the terminal is the terminal information field and is subject to UL-OFDMA. Check if it is designated as a terminal. For example, the terminal checks whether an identifier of the own terminal is set in the terminal information fields 1 to n, and determines that the own terminal is specified when the identifier of the own terminal is set. In this example, as an example, the terminals 1 to 8 receive the trigger frame 501, and among these, the terminals 1 and 2 determine that their own terminals are designated as UL-OFDMA terminals.

  The terminal 1 and the terminal 2 specify the resource unit designated for the own terminal and other parameter information (if any) from the corresponding terminal information field of the own terminal. Examples of other parameters include transmission power, transmission timing adjustment amount, or data type as described above. Also, parameter information necessary for uplink transmission is specified from the common information field. As an example, the transmission packet length (PPDU length) or the like is specified. When the packet length to be transmitted is less than the packet length designated by the access point, the terminals 1 and 2 add padding data to the end. As a result, the corresponding resource unit can notify other terminals that it is busy for the time of the packet length. However, it is not essential to add padding data, and it is possible to add no padding data. Terminal 1 and terminal 2 transmit frames 601 and 701 using designated resource units, respectively, after a predetermined time from completion of reception of trigger frame 501. As an example, the predetermined time can be determined using the IFS time [μs]. The predetermined time may be a SIFS time (= 16 μs) which is a time interval between frames defined by the MAC protocol specification of the IEEE 802.11 wireless LAN, or may be a value larger or smaller than this. A predetermined time value is stored in the common information field and / or the terminal information field, or both, and the terminals 1 and 2 may acquire the time value from the common information field and / or the terminal information field. Good. In addition, the time may be notified in advance by another method such as a beacon frame or another management frame. When the transmission power is designated in the trigger frame 501, the terminal 1 and the terminal 2 use the designated transmission power, and if the transmission timing adjustment amount is designated, the transmission timing is designated in advance. Then, frames 601 and 701 are transmitted. Frames 601 and 701 are transmitted by UL-OFDMA.

  Here, the terminals 1 and 2 transmit, as frames 601, 701, an aggregation frame obtained by concatenating (aggregating) a plurality of subframes each including data. This aggregation frame is called A-MPDU (Aggregate MPDU) in the IEEE 802.11 standard. Each subframe includes delimiter information called a delimiter on the head side, and each subframe can be separated by the delimiter. In each subframe, a sequence number of data set in the frame body field, that is, a sequence number of MSDU (medium access control (MAC) service data unit) is set. Each subframe includes a MAC frame (MPDU) following the delimiter, and a sequence number is set in a Sequence Number subfield (not shown) of a Sequence Control field (see FIG. 6) in the MPDU. As an example, the sequence number of each subframe is set as a continuous integer number. In this example, as shown in FIG. 8, 3, 4, and 5 are set as sequence numbers (SN: Sequence Number) in the three subframes in the frame 601 transmitted from the terminal 1, respectively. Similarly, 27, 28, and 29 are set as sequence numbers (SN) in the three subframes in the frame 701 transmitted from the terminal 2, respectively.

  In addition, in the Ack_Policy field of the QoS Control field of the MPDU of each subframe, “00” (Implicit Block Ack request: Implicit BAR) is used to request a delivery confirmation response immediately (after the SIFS time) to the destination access point. Set. Although an immediate delivery confirmation response is not requested from the destination access point, a Block Ack request frame (BAR frame) is received from the terminal side, or an aggregation frame set in the Implicit Block Ack request is received from the terminal side If a delivery confirmation response is sometimes requested, “11” (Explicit Block Ack request: Explicit BAR) is set. In this case, even if the access point receives a frame from the terminal, the access point does not return a delivery confirmation response to the terminal. Store it in the department.

  In this example, the Ack_Policy field of each subframe in the frame 601 transmitted from the terminal 1 is “00” (Implicit Block Ack request), and the Ack_Policy field of each subframe in the frame 701 transmitted from the terminal 2 is also “00” ( (Implicit Block Ack request). It is assumed that the same Ack_Policy is set for all the subframes included in the same frame.

  Note that the frames transmitted by the terminal 1 and the terminal 2 may be frames having different contents or frames having the same contents. As a general expression, when it is expressed that a plurality of terminals transmit or receive the Xth frame, the contents of these Xth frames may be the same or different. X is an arbitrary value. Similarly, when it is expressed that the terminal transmits a plurality of Xth frames (in time series), the contents of these Xth frames may be the same or different. X is an arbitrary value.

  If the terminal does not have data to transmit in the uplink, the terminal has a frame in a predetermined format, for example, a packet 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. In the access point, when such a packet or frame is received or nothing is received, the terminal may determine that there is no data to be transmitted.

  When the access point 11 receives the frames 601 and 701 transmitted from the terminal 1 and the terminal 2 by UL-OFDMA, the access point 11 inspects FCS information (CRC, etc.) of a plurality of subframes in each frame and determines whether or not the reception is successful. judge. Information on the success / failure of each subframe is stored in a storage unit such as a memory as necessary.

  Further, the access point 11 confirms the Ack_Policy of the frames 601 and 701 of the terminal 1 and the terminal 2, and determines whether or not the delivery confirmation response frame can be transmitted. If both Ack_Policies are “11”, it is determined not to immediately transmit a delivery confirmation response frame (after the SIFS time). If the Ack_Policy of at least one of the terminals is “00” (Implicit Block Ack request), a delivery confirmation response frame is generated. This acknowledgment response frame is, by way of example, a single frame that can include an acknowledgment response for one or more terminals. As such a frame format, a new frame may be defined, or a frame using the BA frame format may be used. Here, a frame using the latter BA frame format is used, and the frame is referred to as a Multi-Station Block Ack (Multi-STA BA) frame.

  Here, since both frames 601 and 701 received from the terminal 1 and the terminal 2 are set to “00” (Implicit Block Ack request) as Ack_Policy in each subframe, it is necessary to generate a delivery confirmation response frame. decide. Then, the access point 11 uses the success / failure of reception of each subframe in all frames (including the frame received this time) received from the terminal after transmitting the previous delivery confirmation response frame, and uses the delivery confirmation response frame (Multi). -STA BA frame).

  Here, the Multi-STA BA frame will be described. The Multi-STA BA frame is a diversion of a Block Ack frame (BA frame) in order to perform delivery confirmation responses to a plurality of terminals in one frame. The frame type may be control (Control), and the frame subtype may be BlockAck, as in a normal BA frame. FIG. 12A shows a format example of the Multi-STA BA frame. FIG. 12B shows an example of the format of the BA Control field in the BA frame, and FIG. 12C shows an example of the format of the BA Information field in the BA frame. When the BA frame is reused, it may be indicated in the BA Control field that the BA frame format is extended to notify the delivery confirmation response regarding a plurality of terminals. For example, in the IEEE 802.11 standard, when the Multi-TID subfield is 1 and the Compressed Bitmap subfield is 0, the current reservation is reserved. This may be used to indicate that the BA frame format is extended to notify delivery confirmation responses regarding a plurality of terminals. Alternatively, in FIG. 12B, the area of bits B3 to B8 is a reserved subfield, but part or all of this area is in a BA frame format expanded to notify delivery confirmation responses for a plurality of terminals. It may be defined to indicate that there is. Alternatively, such notification need not be explicitly performed.

  As an example, the RA field in the BA frame may be a broadcast address or a multicast address. The number of users (number of terminals) to be reported in the BA Information field may be set in the Multi-User subfield of the BA Control field. In the BA Information field, an association ID subfield, a Block Ack starting sequence control (Block Ack Starting Sequence Control) subfield, and a Block Ack bitmap (Block Ack Bitmap) subfield are arranged for each user (terminal). To do. Hereinafter, the Block Ack start sequence control is referred to as “start sequence control subfield”, and the Block Ack bitmap subfield is referred to as “bitmap subfield”.

  An AID is set in the association ID subfield (AID subfield) for user identification. More specifically, as shown in FIG. 12C, as an example, a part of the Per TID Info field is used as an AID subfield. Currently, 12 bits (B0 to B11) are reserved areas. The first 11 bits (B0-B10) are used as the AID subfield.

  In addition, the 12th bit from the head in the Per TID Info subfield (B11 if the head is B0) is used as an indication flag bit (predetermined field) in this embodiment. A method of using the indication flag bit will be described.

  When the access point has successfully received all the frames received so far from the terminal after transmitting the previous acknowledgment frame (Multi-STA BA frame) and all the subframes in the frame received this time, Set the indication flag bit to “1”. In this case, the start sequence control subfield and the bitmap subfield are omitted. This notifies the corresponding terminal that transmission of all subframes included in each of the frames received so far after the previous Multi-STA BA frame has been transmitted and the frames received this time has been successful. To do. The terminal can recognize the successful transmission of the frames received so far (Ack_Policy is “11”) without transmitting the BA request frame. By omitting the above-mentioned two subfields, the size of the Multi-STA BA frame can be reduced and efficiency can be improved.

  On the other hand, the access point failed to receive at least one of all the frames received from the terminal so far after transmitting the previous acknowledgment frame (Multi-STA BA frame) and each subframe in the currently received frame. If it is, the indication flag bit is turned off “0”. In the start sequence control subfield, the sequence number of the first subframe that has been successfully received (the smallest sequence number that has been successfully received) among all the frames and the subframes in the currently received frame is indicated as the start sequence. Set as number (SSN). In the bitmap subfield, a bitmap is set that indicates whether or not reception of the sequence numbers of all the subframes (including subframes in the currently received frame) after the start sequence number (SSN) is successful. The start sequence number (SSN) is not limited to the smallest sequence number that has been successfully received, and may be any sequence number or less.

  The indication flag bit is 1 bit in this example, but may be a plurality of bits. Further, the relationship between the indication flag bits “1” and “0” may be reversed.

  In this sequence example, it is assumed that the access point has successfully received the subframes of sequence numbers 3 and 5 in the frame 601 received from the terminal 1, but has failed to receive sequence number 4 (upper side in FIG. 8). (See shaded area). It is assumed that the reception of subframes with sequence numbers 27, 28, and 29 of the frame 701 received from the terminal 2 is successful.

  Therefore, for the terminal 1, the access point turns off the indication flag bit (B11) to “0”, sets “3” in the start sequence control subfield as the start sequence number (SSN), and “101” in the bitmap subfield. ”Is set. (As shown in FIG. 8, since the bitmap subfield is 8 octets, strictly speaking, after “1010000...” And “101”, zero is set so that the total is 8 octets. In this embodiment, “101” is used for convenience. “1” indicates success and “0” indicates failure. Corresponding to sequence numbers 3, 4, and 5 in order from the left. Note that the relationship between “1” and “0” may be reversed. The AID of the terminal 1 is set in the AID subfield.

  For the terminal 2, the indication flag bit is set to “1”, and the start sequence control subfield and the bitmap subfield are omitted. The AID of the terminal 2 is set in the AID subfield.

  Here, it is assumed that the access point has not received a frame with Ack_Policy of “11” (Exclusive Block Ack request) from terminal 1 and terminal 2 before frames 601 and 701.

  The access point transmits the Multi-STA BA frame 502 after a predetermined time (SIFS time or the like) from the completion of reception of the frames 601 and 701 from the terminal 1 and the terminal 2. The Multi-STA BA frame 502 is transmitted, for example, in the same frequency band as the trigger frame 501 or UL-OFDMA, for example, a band with a basic channel width of 20 MHz.

  The terminals 1 and 2 receive the Multi-STA BA frame 502 and confirm the type and subtype of the frame control field. Detect that Type and Subtype are control and BlockAck, and detect that the value of the RA field is a broadcast address or the like. Thereby, the terminals 1 and 2 grasp that the Multi-STA BA frame that may include the delivery confirmation response (transmission success / failure) with respect to the frames 601 and 701 transmitted by the terminal itself is received. The terminals 1 and 2 send a delivery confirmation response (transmission success / absence) to the frames 601 and 701 transmitted by the own terminal, more specifically, delivery confirmation responses of a plurality of subframes included in the frames 601 and 701, and BA information Identify from the field.

  The terminal 1 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and since this bit is “0”, the start sequence control subfield and The transmission result (CRC inspection result) of the subframes of sequence numbers 3, 4, and 5 is ascertained from the bitmap subfield. More specifically, the success or failure of transmission of sequence numbers 3, 4, and 5 after the start sequence number (SNN) is specified from the bitmap. Since the bitmap is “101”, the terminal recognizes that the transmission of sequence numbers 3 and 5 has succeeded but the transmission of sequence number 4 has failed.

  The terminal 2 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and since this bit is “1”, the sequence numbers 27, 28, It knows that all 29 subframe transmissions were successful.

  Next, the access point transmits a trigger frame 503 after a predetermined time (SIFS time or the like) or an arbitrary time has elapsed since the transmission of the Multi-STA BA frame 502. In the trigger frame 503, it is assumed that the terminal 1 and the terminal 2 are designated as in the trigger frame 501. The resource unit to be used by the terminal 1 and the terminal 2 and other parameter information may be determined as described above.

  The terminal 1 and the terminal 2 receive the trigger frame 503, and after a predetermined time from the completion of reception, the terminals 1 and 2 transmit frames 602 and 702, each of which aggregates a plurality of subframes, using designated resource units. Assume that Ack_Policy of the frame 602 is “11” (Explicit Block Ack request), and the sequence numbers of the aggregated subframes are 6, 7, and 8, respectively. Further, it is assumed that Ack_Policy of the frame 702 is “00” (Implicit Block Ack request), and the sequence numbers of the aggregated subframes are 30, 31, and 32, respectively.

  The access point receives frames 602 and 702 transmitted from terminal 1 and terminal 2 by UL-OFDMA. The access point checks each subframe of the frame 602 received from the terminal 1 and determines that the subframe has been successfully received. Since Ack_Policy is “11”, it is determined that an immediate delivery confirmation response (after SIFS time) to terminal 1 is unnecessary. Further, each subframe of the frame 702 received from the terminal 2 is inspected, and it is determined that the subframe has been successfully received. Since Ack_Policy is “00”, it is determined that an immediate delivery confirmation response (after SIFS time) needs to be transmitted to the terminal 2.

  The access point generates a Multi-STA BA frame 504 including only a delivery confirmation response to the terminal 2. The AID of the terminal 2 is set in the AID subfield (B0-B10 of the Per TID Info field), and “1” is set in the indication flag bit (B11). The start sequence control subfield and the bitmap subfield are omitted. The access point transmits a Multi-STA BA frame 504 after a predetermined time from completion of reception of the frames 602 and 702.

  Terminal 1 and terminal 2 receive Multi-STA BA frame 504. The terminal 2 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and since this bit is “1”, the sequence numbers 30, 31, It knows that all 32 subframe transmissions were successful. Since there is no AID subfield in which the AID of the own terminal is set, the terminal 1 determines that the delivery confirmation response for the own terminal is not included in the Multi-STA BA frame 504. Alternatively, since the terminal 1 has transmitted a frame with Ack_Policy of “11” (Explicit Block Ack request), even if the Multi-STA BA frame 504 is received, it is determined that the terminal 1 is irrelevant and discarded. Good. Alternatively, the access point may set the address of the terminal 2 in the RA field (Address1 field) of the frame 504.

  Next, the access point transmits a trigger frame 505 after a predetermined time (SIFS time or the like) or an arbitrary time has elapsed since the transmission of the Multi-STA BA frame 504. In the trigger frame 505, it is assumed that the terminal 1 and the terminal 2 are designated as in the trigger frames 501 and 503. The resource unit to be used by the terminal 1 and the terminal 2 and other parameter information may be determined as described above.

  The terminal 1 and the terminal 2 receive the trigger frame 505, and transmit frames 603 and 703 in which a plurality of subframes are aggregated after a predetermined time from completion of the reception. Assume that Ack_Policy of the frame 603 is “11” (Explicit Block Ack request), and the sequence numbers of the aggregated subframes are 9, 10, and 11, respectively. Further, it is assumed that Ack_Policy of the frame 703 is “00” (Implicit Block Ack request), and the sequence numbers of the aggregated subframes are 33, 34, and 35, respectively.

  The access point receives frames 603 and 703 transmitted from terminal 1 and terminal 2 by UL-OFDMA. The access point checks each subframe of the frame 603 received from the terminal 1 and determines that the subframe has been successfully received. Since Ack_Policy is “11”, it is determined that an immediate delivery confirmation response (after SIFS time) to terminal 1 is unnecessary. Further, each subframe of the frame 703 received from the terminal 2 is inspected, and it is determined that the reception of these subframes has been successful. Since Ack_Policy is “00”, it is determined that an immediate delivery confirmation response (after SIFS time) needs to be transmitted to the terminal 2.

  The access point generates a Multi-STA BA frame 506 including only the delivery confirmation response to the terminal 2. The AID of the terminal 2 is set in the AID subfield (B0-B10 of the Per TID Info field), and “1” is set in the indication flag bit (B11). The start sequence control subfield and the bitmap subfield are omitted. The access point transmits a Multi-STA BA frame 506 after a predetermined time from completion of reception of the frames 603 and 703.

  Terminal 1 and terminal 2 receive Multi-STA BA frame 506. The terminal 2 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and since this bit is “1”, the sequence numbers 33, 34, All 35 subframe transmissions are known to be successful. Since there is no AID subfield in which the AID of the own terminal is set, the terminal 1 determines that the delivery confirmation response for the own terminal is not included in the Multi-STA BA frame 506. Alternatively, since the terminal 1 has transmitted a frame with Ack_Policy of “11” (Exclusive Block Ack request), even if the Multi-STA BA frame 506 is received, the terminal 1 determines that it is irrelevant to itself and ignores or discards it. May be.

  Next, the access point transmits a trigger frame 507 after a predetermined time (SIFS time or the like) or an arbitrary time has elapsed since the transmission of the Multi-STA BA frame 506. In the trigger frame 507, it is assumed that the terminal 1 and the terminal 2 are designated as in the trigger frames 501, 503, and 505. The resource unit to be used by the terminal 1 and the terminal 2 and other parameter information may be determined as described above.

  Terminal 1 and terminal 2 receive trigger frame 507, and transmit frames 604 and 704 in which a plurality of subframes are aggregated after a predetermined time from completion of reception. The Ack_Policy of the frame 604 is “00” (Implicit Block Ack request), and the sequence numbers of the aggregated subframes are 12, 13, and 14, respectively. Further, it is assumed that Ack_Policy of the frame 704 is “00” (Implicit Block Ack request), and the sequence numbers of the aggregated subframes are 36, 37, and 38, respectively.

  The access point receives frames 604 and 704 transmitted from terminal 1 and terminal 2 by UL-OFDMA. The access point checks each subframe of the frame 604 received from the terminal 1 and determines that the subframe has been successfully received. Since Ack_Policy is “00”, it is determined that an immediate delivery confirmation response (after SIFS time) needs to be transmitted to the terminal 1. Further, each subframe of the frame 704 received from the terminal 2 is inspected, and it is determined that the subframe has been successfully received. Since Ack_Policy is “00”, it is determined that an immediate delivery confirmation response (after SIFS time) needs to be transmitted to the terminal 2.

  The access point generates a Multi-STA BA frame 508 including a delivery confirmation response for the terminal 1 and the terminal 2.

  More specifically, regarding the terminal 1, frames 602 and 603 of an explicit BA request (Ack_Policy = 11) are received from the terminal 1 before the frame 604, and a delivery confirmation response to the frames 602 and 603 is not performed. Therefore, in addition to the frame 604 received this time, a delivery confirmation response to the frames 602 and 603 is also included in the Multi-STA BA frame 508. Since the inspection results of all subframes in which all of the frames 602, 603, and 604 are aggregated have been successfully received, “1” is set to the indication flag bit (B11), and the start sequence control subfield and the bitmap sub The field is omitted. The AID of the terminal 1 is set in the AID subfield (B0-B10 of the Per TID Info field).

  Regarding the terminal 2, since the inspection result of the subframe of the frame 704 received this time is successful, the AID of the terminal 2 is set in the corresponding AID subfield (B0-B10 of the Per TID Info field), and the indication flag bit is set. “1” is set in (B11). The start sequence control subfield and the bitmap subfield are omitted. In the case of the terminal 2, since all of the frames 701 to 703 received before the frame 704 have already been acknowledged, there is no need to consider them this time.

  The access point transmits a Multi-STA BA frame 508 after a predetermined time from completion of reception of the frames 604 and 704. Terminal 1 and terminal 2 receive Multi-STA BA frame 508 transmitted from the access point.

  The terminal 1 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the terminal itself is set, and recognizes that this bit is “1”. Thus, in addition to the frame 604 transmitted this time, for the frames 602 and 603 transmitted in the past, it is understood that transmission of all the subframes aggregated in these frames has been successful. More specifically, regarding the frames 602 and 603 that have not received the delivery confirmation response due to the explicit BA request, and the frame 604 that is transmitted by the implicit BA request this time, transmission of all subframes aggregated in these frames is transmitted. Know that was successful. Accordingly, the Multi-STA BA frame length transmitted from the access point can be shortened, and the terminal 1 can obtain a delivery confirmation response without transmitting a BAR frame for the frames 602 and 603.

  The terminal 2 checks the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the terminal itself is set, and recognizes that this bit is “1”. As a result, it is understood that the transmission of the subframes of sequence numbers 36, 37, and 38 that have been aggregated in the frame 704 transmitted this time has succeeded.

  FIG. 13 shows a second example of an operation sequence between the access point 11 and the terminals 1 and 2 according to the present embodiment. The difference from the first sequence example shown in FIG. 8 will be mainly described.

  In the first sequence example, all the subframes of the frame 603 transmitted by the terminal 1 have been successfully received at the access point. On the other hand, in the second sequence example, among the subframes of sequence numbers 9, 10, and 11 aggregated in the frame 603, reception of the subframe of sequence number 11 has failed at the access point (see FIG. 13 (see the shaded area below 13). Due to this, the operation of the access point after the terminal 1 has transmitted the Implicit BAR frame 604 and the subsequent operation of the terminal 1 are different from those in the first sequence example. The terminal 2 is the same as the first sequence example.

  The access point checks each subframe of the frame 604 received from the terminal 1 and determines that the subframe has been successfully received. Since Ack_Policy is “00”, it is determined that an immediate delivery confirmation response (after SIFS time) needs to be transmitted to the terminal 1. With respect to the terminal 1, the access point receives frames 602 and 603 of an explicit BA request (Ack_Policy = 11) from the terminal 1 before the frame 604, and does not perform a delivery confirmation response to these frames 602 and 603. Therefore, in addition to the frame 604 received this time, it is determined that a delivery confirmation response to the frames 602 and 603 is also included in the Multi-STA BA frame 511.

  At this time, reception of the subframe of sequence number 11 that was aggregated in the frame 603 was not successful. That is, reception of at least one subframe among a plurality of subframes aggregated in frames 602 to 604 failed. Therefore, the access point sets “0” in the indication flag bit (B11). The AID of the terminal 1 is set in the AID subfield (B0-B10 of the Per TID Info field).

  Further, the access point specifies the smallest sequence number that has succeeded in receiving the subframes aggregated in these frames 602, 603, and 604 as a start sequence number (SSN). Here, since the sequence number (SN) 6 of the first subframe aggregated in the frame 602 is the smallest, this is set as the start sequence number (SSN). Set the start sequence number in the start sequence control subfield. Also, the subframe inspection results from sequence number 6 to the last sequence number 14 are mapped from the first bit of the bitmap subfield. Of the subframes from sequence number 6 to the last sequence number 14, only sequence number 11 has failed to be received, and other sequence numbers have been successfully received. Therefore, “111110111” is set from the beginning of the bitmap field. Corresponding to the inspection results of sequence numbers 6 to 14 in order from the left bit. “1” is reception success and “0” is reception failure. However, the relationship between “1” and “0” may be reversed. The SSN may be a value smaller than the smallest sequence number that has been successfully received. In this case, the inspection result after the sequence number of the value may be mapped to the bitmap subfield.

  As for the terminal 2, as in the first sequence example, since the inspection result of the subframe of the frame 704 was successfully received, “1” is set to the indication flag bit (B 11). The AID of the terminal 2 is set in the AID subfield (B0-B10 of the Per TID Info field). The start sequence control subfield and the bitmap subfield are omitted.

  In this way, the access point generates the Multi-STA BA frame 511 including the delivery confirmation response of the terminal 1 and the terminal 2. The access point transmits a Multi-STA BA frame 511 after a predetermined time from completion of reception of the frames 604 and 704.

  Terminal 1 and terminal 2 receive the Multi-STA BA frame 511 from the access point.

  The terminal 1 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and recognizes that this bit is “0”. Therefore, the start sequence control field and the bitmap subfield are confirmed. Since “6” is set as the SSN in the start sequence control field and “111110111” is set in the bitmap subfield, the transmission of the sequence numbers 6 to 10 and 12 to 14 is successful. It is determined that transmission of sequence number 11 has failed. As described above, the terminal 1 can also obtain a delivery confirmation response together with the frame 604 for the frames 602 and 603 transmitted by the Implicit BA request before the frame 604. That is, the terminal 1 can obtain a delivery confirmation response together with the delivery confirmation response of the frame 604 without transmitting a BAR frame for the frames 602 and 603. Therefore, there is no problem that the terminal 1 is not notified of the delivery confirmation response for the frames 602 and 603.

  On the other hand, the terminal 2 confirms the indication flag bit following the AID subfield (B0-B10 of the Per TID Info field) in which the AID of the own terminal is set, and since this bit is “1”, the terminal 2 in the frame 704 It is understood that the transmission of the subframes of sequence numbers 36, 37, and 38 is all successful.

  In the sequence of FIG. 13 described above, the terminal 1 transmits the Implicit BAR aggregation frame 604 (that is, A_MPDU with Ack_Policy = 00), but may transmit a BAR frame with Ack_Policy = 00 as another sequence. In this case as well, the access point may similarly generate a delivery confirmation response for the frames 602 and 603 of the explicit BAR received before the BAR frame and return it to the terminal 1. Since the BAR frame does not include data with a sequence number, there is no delivery confirmation response to the BAR frame.

  FIG. 14 shows a third example of the operation sequence between the access point 11 and the terminals 1 and 2 according to this embodiment. The difference from the sequence example shown in FIG. 13 will be mainly described. In the sequence of FIG. 13, the frame 604 including the subframes having the sequence numbers 12 to 14 is transmitted from the terminal 1. However, in this example, the frame 614 including the sequence number 4 and the 12 and 13 subframes is transmitted. The subframe with sequence number 4 is a retransmission subframe.

  The access point transmits a Multi-STA BA frame 512 to the frames 614 and 704 received from the terminals 1 and 2. As an example of the setting for the terminal 1, the start sequence number is 4 (SSN = 4) and the bitmap is “1011111011”. The indication flag is “0” (with a bitmap). For terminal 2, the same contents as in FIG. Sequence numbers 4 to 13 correspond in order from the left of the bitmap. The bit of sequence number 5 is the second “0” from the left. This is because the subframe of sequence number 5 has not been received after the frame 602 of the explicit BAR (or because it has already been answered in the frame 502). Since the terminal already knows the inspection result of sequence number 5, it is not necessary to confirm the inspection result of sequence number 5 with the current bitmap.

  As another example, the start sequence number may be 4 (SSN = 4) and the bitmap may be “1111111011”. The access point may have already received the subframe of sequence number 5 in frame 601 and responded once in frame 502, but may set the bit corresponding to sequence number 5 to “1”. In this case as well, since the terminal already knows the inspection result of sequence number 5, it is not necessary to confirm the inspection result of sequence number 5 with the current bitmap.

  FIG. 15 shows a fourth example of the operation sequence between the access point 11 and the terminals 1 and 2 according to the present embodiment. The difference from the sequence example shown in FIG. 13 will be mainly described. In the sequence of FIG. 13, all the subframes (SN = 6, 7, 8) in the frame 602 transmitted from the terminal 1 have been successfully received, but in this example, the subframes having the sequence numbers 6 and 7 have failed to be received. doing.

  The access point responds with a Multi-STA BA frame 515 to the frames 604 and 704 received from the terminals 1 and 2. At this time, as a setting example for the terminal 1, the start sequence number is 8 (SSN = 8), and the bitmap is “1110111”. The indication flag is “0” (with a bitmap). The subframes with sequence numbers 6 and 7 have failed to be received at the access point. Since the access point cannot grasp the sequence number of the subframe, the smallest sequence number that has been successfully received is set as the start sequence number (SSN).

  The terminal 1 that has received the Multi-STA BA frame 515 specifies that the SSN is 8, and confirms whether or not reception is possible after the sequence number 8 by using a bitmap. Regarding the subframes of sequence numbers 6 and 7 transmitted in the frame 602, it can be recognized that the access point has failed to receive because the SSN is 8.

  In each of the above-described sequences, the access point specified all the frames of the explicit BAR (frames 602 and 603 in this example) received from the terminal 1 before the frame 604 of the implicit BAR (or 614, the same applies hereinafter). Then, all the identified frames 602 and 603 are subjected to a delivery confirmation response together with the frame 604 received this time.

  However, not all of the frames of the explicit BAR need to be the target of the delivery confirmation response. As a first example, at least one or a predetermined number or less of explicit BAR frames continuously received before the frame 604 of the implicit BAR may be targeted. When this example is applied to the above-described sequence, the frame 603 may be the target of the delivery confirmation response, and the frame 602 may not be the target of the delivery confirmation response. Also, as a second example, out of the explicit BAR frames continuously received before the frame 604 of the Implicit BAR, frames received during a certain period of time before the reception of the frame 604 are received. It may be a target. Further, as a third example, a certain percentage of frames in the explicit BAR received continuously before the frame 604 of the implicit BAR may be the target of the delivery confirmation response. Note that in any case, when the frame of the previous Implicit BAR is received, the frame received after the frame of the previous Implicit BAR is the target.

  In any case of the first example to the third example, the frame 604 received this time is a target of a delivery confirmation response. Whether the indication flag bit is set to “1” or “0” may be determined according to whether or not the reception of the subframe within the frame that is the target of the delivery confirmation response is successful. Also, in the first to third examples, when all the frames that are the targets of the delivery confirmation response have been successfully received, the start sequence control subfield is left while the bitmap subfield is omitted, but the start sequence control sub A start sequence number (SSN) may be set in the field. The SSN is the smallest sequence number that has been successfully received or less than the sequence number of the frame that is the target of the delivery confirmation response.

  In the sequence example described above, a frame (aggregation frame) in which a plurality of subframes are aggregated is transmitted from each of terminal 1 and terminal 2, but the number of subframes to be aggregated is not plural and may be one. That is, the target frame in the present embodiment may be any frame as long as it has a format that can notify whether or not a delivery confirmation response is requested.

  In the sequence example described above, a plurality of terminals are designated by a trigger frame, and frames are UL-MU transmitted from the plurality of terminals. However, the number of designated terminals is not limited to a plurality, and may be one. Also, this embodiment can be applied to a case where a frame is transmitted from a terminal to an access point on a normal CSMA / CA basis instead of trigger frame-driven uplink transmission. In this case, the delivery confirmation response frame transmitted from the access point may be a BA frame as in the case of the Multi-STA BA frame. That is, as described above, the indication flag bit may be set to control the setting or omission of the start sequence control subfield and the bitmap subfield. In the case of single user transmission, the setting of AID may be omitted.

  FIG. 16 is a functional block diagram of a wireless communication device mounted on the access point 11. As described above, the access point 11 is connected to at least the network on the side of the terminals 1 to 8 shown in FIG. 1, and can also be connected to another network. In FIG. 19, the structure of the radio | wireless communication apparatus connected to the network of the terminals 1-8 side is shown.

  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, and 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 form a wireless communication unit or an RF integrated circuit that transmits and receives a frame via an antenna. . All or part of the processing of the control unit 101 and the processing of the digital area of the transmission unit 102 and the reception unit 103 may be performed by software (program) that operates on a processor such as a CPU, or by hardware. It may be performed by both of these software and hardware. The access point may include a processor that performs processing of all or part 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 MRAM. The upper layer may store the frame received from another network in the buffer 104 for relay to the network on the terminal 1-8 side. Further, a frame received from the terminal-side network or its payload may be passed from the control unit 101 to the upper layer via the buffer 104. The upper layer may perform communication processing above the MAC layer such as TCP / IP and UDP / IP. Alternatively, TCP / IP and UDP / IP may be performed by the control unit 101, and the upper layer may perform processing of a higher application layer. The upper layer operation may be performed by software (program) processing 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 part of the MAC layer processing and physical layer processing (for example, OFDMA processing, MU communication processing, etc.). 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 periodically control to transmit a beacon frame in order to notify the access point BSS (Basic Service Set) attributes, synchronization information, and the like. The control unit 101 may include a clock generation unit that generates a clock, and may manage the time in the apparatus 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. Or the control part 101 may receive the input of the clock produced | generated by the external clock generation part, and may manage the time in an apparatus using the said clock.

  The control unit 101 receives an association request from the terminal, performs an association process, and exchanges necessary information (such as capability information indicating whether OFDMA can be performed) or the like. Then, a radio link is established with the terminal. If necessary, an authentication process may be performed with the terminal prior to the association process. The control unit 101 may grasp the state of the buffer 104 by checking the buffer 104 periodically to determine whether there is data addressed to the terminal. Alternatively, the control unit 101 may confirm the state of the buffer 104 by an external trigger such as the buffer 104. The control unit 101 may manage terminals that have established wireless links in groups. A group identifier (group ID or the like) may be assigned to each group to notify a terminal belonging to the BSS of a list of terminals and groups.

  The control unit 101 selects a plurality of terminals that are targets of UL-MU communication (here, UL-OFDMA) from terminals that have established a radio link, and selects resource units to be used by each of the plurality of terminals. select. The terminals to be selected may be selected from the same group, or all terminals in the group may be selected. For each selected terminal, other parameters such as packet length (PPDU length, etc.) and transmission power are determined as necessary. These details are as described above. Note that the correspondence between resource units and resource unit identifiers and information on 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 the information may be notified by a trigger frame. The control unit 101 sets information specifying the selected terminal, information specifying the resource unit, and other parameters in the common information field and / or terminal information field in the trigger frame. Information regarding the length of the period during which communication is continued may be set in the common information field of the trigger frame.

  The control unit 101 outputs a trigger frame to the transmission unit 102 at the timing when the access right to the wireless medium is acquired according to CSMA / CA, or at a predetermined timing. The transmission unit 102 generates a physical packet by performing desired physical layer processing such as encoding and modulation processing and addition of a physical header to the input trigger frame. Further, DA conversion, filter processing for extracting a desired band component, frequency conversion (up-conversion) to a radio frequency, and the like are performed on the physical packet. The transmitting unit 102 amplifies the radio frequency signal obtained by the above with a preamplifier, and radiates it as a radio wave from one or a plurality of antennas. A plurality of antennas may be used to control transmission directivity. As an example, the trigger frame is transmitted by a single user in a channel width band.

  A signal received by the antenna is processed in the receiving unit 103. For example, signals of frames (including aggregation frames) returned from a plurality of terminals by UL-MU are received simultaneously by the antenna. The received signal is amplified by a low noise amplifier (LNA), frequency-converted (down-converted) to baseband, and a desired band component is extracted by filtering processing. The extracted signal 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, frames from a plurality of terminals are input to the control unit 101, respectively. Is done. The physical layer processing includes frame extraction for each resource unit in the case of UL-OFDMA, spatial separation of frames for each terminal in the case of UL-MU-MIMO, and both of these processing in the case of UL-OFDMA & MU-MIMO. including. In addition, when performing OFDMA, a receiving system may be arrange | positioned for every antenna, and the frequency band corresponding to each may differ. In this case, the reception system may be arranged in resource unit units. Or each receiving system respond | corresponds to the same frequency band, and you may synthesize | combine the signal received by these receiving systems by a diversity technique. In this case, the signal of each resource unit may be extracted by digital filter processing.

  After transmitting the trigger frame, the control unit 101 performs an error check on frames simultaneously received from each terminal by UL-OFDMA (in the case of an aggregation frame, an error check is performed for each of a plurality of subframes (data frames) in the aggregation frame). Do. Here, it is assumed that the frame is an aggregation frame. The inspection results (success / failure) of these terminals are stored in a storage unit such as a memory in association with each sequence number. The Ack_Policy (Implicit BAR or Explicit BAR) of the frame received from each terminal is checked, and a delivery confirmation response frame (in this case, a Multi-STA BA frame) is generated according to the Ack_Policy of each terminal.

  The delivery confirmation response frame to be generated includes a delivery confirmation response for the terminal in which Ack_Policy transmitted the frame of Implicit BAR, and does not include the delivery confirmation response for the terminal in which Ack_Policy transmitted the frame of Explicit BAR. When Ack_Policy of all terminals is an explicit BAR, a delivery confirmation response frame is not generated.

  For the terminal that Ack_Policy transmitted the frame of the Implicit BAR, the inspection result of all the subframes in these frames for the frame received this time and all the frames of the Explicit BAR received before the frame received this time (Reception success / failure) is confirmed by accessing a storage unit such as a memory. “All frames of the explicit BAR received before the frame received this time” means, in other words, received after receiving the previous frame of the implicit BAR and received by the explicit BAR before the frame received this time It is a frame. Here, “all frames of the Explicit BAR received before the frame received this time” is the target of the delivery confirmation response, but as described above, the determination of the range of the frame that is the target of the delivery confirmation response is as follows. Various modifications are possible.

  If the inspection results of all confirmed subframes are successfully received, the identifier (AID or the like) of the terminal is set in the AID subfield corresponding to the terminal, and the indication flag bit following the AID subfield is set, Set to “1”. In this case, the start sequence control subfield and the bitmap field of the terminal are omitted.

  On the other hand, if at least one inspection result among all the confirmed subframe inspection results is a reception failure, the identifier (AID or the like) of the terminal is set in the AID subfield corresponding to the terminal, and the AID The indication flag bit following the subfield is set to “0”. Then, the minimum sequence number that has been successfully received among these subframes is set as the start sequence number (SSN) in the start sequence control subfield, and the reception success / failure for subframes with sequence numbers after SSN is set at the top. Sets the bitmap allocated from the bits in the bitmap subfield. Thereby, the inspection results of all sequence numbers transmitted by the terminal with the sequence numbers after SSN are reflected in the bitmap (up to inspection results for the size of the bitmap can be reflected at the maximum). A value smaller than the smallest sequence number that has been successfully received may be used as the SSN. In this case, a bitmap may be set for sequence numbers after the value.

  The control unit 101 transmits the delivery confirmation response frame (Multi-Station BA frame) generated in this way after SIFS time after completion of UL-OFDMA reception (S105). Here, one delivery confirmation response frame (Multi-Station BA frame) transmitted in common to a plurality of terminals is transmitted, but a delivery confirmation response frame (BA frame or the like) may be generated and transmitted separately for each terminal. . In this case, a delivery confirmation response frame to each terminal may be transmitted simultaneously (DL-MU transmission), or a delivery confirmation response frame (BA frame) may be transmitted individually individually. As a modification, individual acknowledgment frames may be simultaneously transmitted to a plurality of terminals by DL-OFDMA.

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

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

  FIG. 17 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 shown in FIG.

  The wireless communication apparatus includes a control unit 201, a transmission unit 202, a reception unit 203, at least one antenna 1, 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 or an RF integrated circuit that transmits and receives frames. All or part of the processing of the control unit 201 and the processing of the digital area of the transmission unit 202 and the reception unit 203 may be performed by software (program) that operates on a processor such as a CPU, or by hardware. It may be performed by both of these software and hardware. The terminal may include a processor that performs processing of all or part 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 nonvolatile memory such as a NAND or MRAM. The upper layer generates a frame to be transmitted to another terminal, the access point 11, or a device on another network such as a server, and stores it in the buffer 204 or receives it from another terminal, the access point or the device, etc. A frame is received from the control unit 201 via the buffer 204. The upper layer may perform communication processing above the MAC layer such as TCP / IP and UDP / IP. TCP / IP and UDP / IP may be processed by the control unit 201, and the upper layer may perform processing of an upper application layer. The upper layer operation may be performed by software (program) processing 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 MAC layer processing. 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. The control unit 201 may include a clock generation unit that generates a clock, and may manage the time in the apparatus 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 generate an external clock generation unit, receive a clock input, and manage the time in the apparatus using the clock.

  For example, the control unit 201 receives a beacon frame from the access point 11 and grasps the BSS attribute and synchronization information of the access point 11, and then performs an association process by making an association request to the access point 11. As a result, the wireless link is established with the access point 11 by exchanging necessary information (capability information indicating whether or not MU communication such as OFDMA can be performed) such as mutual capabilities and attributes. The control unit 201 may perform an authentication process with the access point in advance as necessary. The control unit 201 may grasp the state of the buffer 204 by checking the buffer 204 periodically to determine whether there is data for uplink transmission. Alternatively, the control unit 201 may check the state of the buffer 204 in response to an external trigger such as the buffer 204. After confirming data to be transmitted to the access point 11 in the buffer 204, the control unit 201 obtains an access right (transmission right) to the wireless medium based on CSMA / CA or the like, generates a frame such as a data frame, and transmits it. You may transmit via the part 202 and the antenna 1A.

  The transmission unit 202 performs processing of a desired physical layer (including processing related to MU communication such as OFDMA) such as encoding and modulation processing and addition of a physical header to the frame input from the control unit 201 to perform physical packet processing. Is generated. Also, DA conversion, filter processing for extracting a desired band component, frequency conversion (up-conversion) to a radio frequency, and the like are performed on the physical packet. The transmission unit 202 amplifies the radio frequency signal obtained by these using a preamplifier, and radiates it as a radio wave from one or a plurality of antennas. In the case where a plurality of antennas are provided, the directivity of transmission can be controlled using a plurality of antennas.

  The signal received by the antenna 1A is processed by the receiving unit 203. The received signal is amplified by the LNA in the receiving unit 203, frequency-converted (down-converted) to baseband, and a desired band component is extracted by a filering process. The extracted signal 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 frame such as a data frame is input to the control unit 201. .

  When the control unit 201 receives a trigger frame from the access point 11, the control unit 201 confirms whether or not the own terminal is designated as an UL-MU (here, UL-OFDMA) target in the trigger frame. As described above, the determination as to whether the own terminal is designated may be confirmed based on whether the identification information of the own terminal is set in any terminal information field. Only when the group ID is set in the common information field and the own terminal belongs to the group of the group ID, it may be confirmed whether the own terminal is specified in the terminal information field. Alternatively, there is a rule that all terminals belonging to the group ID set in the common information field are permitted as a target of UL-OFDMA, and when the group ID is set in the common information field, the group ID is automatically set. It may be determined whether or not the terminal is designated based on whether or not the terminal belongs. In addition, when information related to a period during which communication is continued is set in the common information field or the like of the trigger frame, the control unit 201 uses a CSMA / CA-based single user communication during this period, for example. You may decide not to do.

  When the own terminal is designated as the target of UL-OFDMA, the control unit 201 can change the resource unit used by the own terminal and other parameter information as necessary to the common information field or the own terminal. From the terminal information field, or both. In addition, the control unit 201 determines whether or not to immediately request a delivery confirmation response to a frame transmitted by UL-OFDMA (after the SIFS time). Based on these, the control unit 201 generates a frame such as a data frame (may be an aggregation frame).

  More specifically, when requesting a delivery confirmation response immediately (after SIFS time), set the Ack_Policy field of the QoS Control field to “00” (Implicit BAR) and no delivery confirmation response is required immediately (after SIFS time). Otherwise, the Ack_Policy field is set to “11” (Explicit BAR).

  A method for determining whether or not a delivery confirmation response is requested is not limited to a specific method. As an example, it may be determined according to the type of data to be transmitted, or a request for a delivery confirmation response is determined to be given for a certain period of time or a certain amount of transmitted data, and otherwise the request is determined to be none. May be. Alternatively, the presence / absence of a request may be determined randomly, or may be determined by a method other than the method described here.

  In addition, when a packet length (PPDU length or the like) is designated, the control unit 201 generates a frame so that a packet to be transmitted is equal to or shorter than the packet length. If the packet length is less than the designated packet length, padding data may be added to the end of the frame. If an access category or the like is designated, data of the designated access category is read out. The generated frame may be an aggregation frame including a plurality of data frames (subframes).

  The control unit 201 performs control so that the frame generated in this manner is transmitted by a designated resource unit after a predetermined time from completion of reception of the trigger frame. When the adjustment amount of the transmission timing is designated, the transmission is performed at a timing shifted by the adjustment amount with respect to a predetermined time from the reception of the trigger frame. The frame is transmitted as a physical packet via the transmission unit 202 and the antenna 1A. The operation of the transmission unit 202 is as described above.

  After transmitting the frame, the control unit 201 determines whether a delivery confirmation frame (such as a Multi-STA BA frame) including a delivery confirmation response for the terminal itself has been received. When an Implicit BAR frame (Ack_policy is “00”) is transmitted, it waits for reception of a delivery confirmation response frame (here, a Multi-STA BA frame) transmitted from the access point after SIFS time.

  The control unit 201 analyzes the delivery confirmation response frame, and when the identifier of the own terminal is set in any AID subfield (see FIG. 12), the delivery confirmation response frame including the delivery confirmation response for the own terminal Is received. The control unit 201 confirms the indication flag bit following the AID subfield in which the identifier of the own terminal is set.

  If the bit is “1”, it is determined that the start sequence control subfield and the bitmap field of the own terminal are omitted. Then, regarding the frame transmitted this time and all frames of the explicit BAR transmitted before the frame transmitted this time, it is determined that transmission of all subframes in these frames is successful. “All frames of the explicit BAR transmitted before the frame transmitted this time” means, in other words, transmitted after transmitting the frame of the implicit BAR last time, and transmitted by the explicit BAR before the frame transmitted this time. It is a frame. Here, all frames of the explicit BAR transmitted before the frame transmitted this time are the targets of the delivery confirmation response, but as described above, there are various methods for determining the range of the frames that are the targets of the delivery confirmation response. Deformation is possible.

  On the other hand, if the indication flag bit is “0”, the start sequence number (SSN) is specified from the start sequence control subfield, and the success / failure of transmission for subframes of sequence numbers after SSN is set in the bitmap subfield. Figure out from the bitmap that has been. As an example, the bit map reflects the inspection results of all sequence numbers transmitted by the terminal using the sequence numbers after SSN (up to the inspection result corresponding to the size of the bitmap).

  A subframe for which transmission has failed may be retransmitted at another transmission opportunity. For example, when the terminal is designated in the trigger frame after the next time, the frame including the data of the subframe may be retransmitted, the CSMA / CA base, the RTS (Request to Send) frame, and the CTS (Clear to Send) An access right may be acquired by transmitting and receiving a frame, and a frame including a subframe may be retransmitted (single user transmission). You may perform resending by methods other than these.

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

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

  FIG. 18 is a flowchart of an example of the operation of the access point according to the first embodiment. The access point control unit 101 selects a plurality of terminals (or a plurality of wireless communication apparatuses) that are targets of UL-MU (here, UL-OFDMA), and selects a resource unit to be used by the selected terminals. (S101). Other parameters such as transmission power are determined for each selected terminal as necessary. Information specifying the selected terminal and resource unit and other parameter information are set in the terminal information field for each terminal. In addition, information commonly notified to each terminal (for example, packet length) is set in the common information field. The control unit of the access point generates a trigger frame in which these pieces of information are set in the terminal information field and the common information field (S101 in the same).

  After transmitting the trigger frame, the access point control unit 101 receives a frame (here, an aggregation frame including a plurality of subframes) transmitted from a plurality of terminals specified by the trigger frame, respectively, by a specified resource unit. Wait. The control unit 101 simultaneously receives (in this case, UL-OFDMA reception) frames that are multiplexed and transmitted from the plurality of terminals via the reception unit 102 (S102).

  The control unit 101 performs a check (CRC check or the like) on whether or not each of the plurality of subframes included in the frame of each terminal has been successfully received, and checks the check result (success / failure) of these terminals in each sequence. The information is stored in a storage unit such as a memory in association with the number (S103).

  The access point control unit 101 checks the Ack_Policy (Implicit BAR or Explicit BAR) of the frame received from each terminal, and determines a delivery confirmation response frame (in this case, a Multi-STA BA frame) according to the Ack_Policy of each terminal. Generate (S104). Note that the Ack_Policy of the plurality of subframes included in the frame is the same.

  At this time, the delivery confirmation response frame includes only the delivery confirmation response of the terminal whose Ack_Policy has transmitted the Implicit BAR frame, and does not include the delivery confirmation response of the terminal whose Ack_Policy has transmitted the explicit BAR frame.

  For the terminal to which Ack_Policy transmitted the frame of the Implicit BAR, for example, the frame received this time and all the frames of the Explicit BAR transmitted continuously before the frame received this time are all in these frames. The inspection result of the subframe (whether reception is successful or not) is confirmed by accessing a storage unit such as a memory.

  If the inspection results of all confirmed subframes are successfully received, the identifier (AID or the like) of the terminal is set in the AID subfield corresponding to the terminal, and the indication flag bit following the AID subfield is set, “1” is set (S104). In this case, the start sequence control subfield and the bitmap field of the terminal are omitted.

  On the other hand, if at least one inspection result among all the confirmed subframe inspection results is a reception failure, the identifier (AID or the like) of the terminal is set in the AID subfield corresponding to the terminal, and the AID The indication flag bit following the subfield is set to “0” (S104). The smallest sequence number that has been successfully received among these subframes is set as the start sequence number (SSN) in the start sequence control subfield, and the first bit indicates whether reception has succeeded for subframes with sequence numbers after SSN. The bitmap allocated from is set in the bitmap subfield. Thereby, the inspection results of all sequence numbers transmitted by the terminal with the sequence numbers after SSN are reflected in the bitmap (up to inspection results for the size of the bitmap can be reflected at the maximum). The SSN may be smaller than the smallest sequence number that has been successfully received. In this case, the inspection result of the sequence number after the value may be assigned to the bitmap.

  The access point control unit 101 transmits the delivery confirmation response frame generated in this way after a predetermined time such as SIFS time from the completion of reception of the UL-OFDMA signal (S105).

  FIG. 19 is a flowchart of an example 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 reception unit 202 (S201). In the trigger frame, for example, information for specifying a plurality of terminals as UL-OFDMA targets, information on parameters specified for each terminal (for example, resource units used by the terminal, transmission power, etc.), etc. Information of parameters specified in common (for example, packet length) is set.

  The control unit 201 of the terminal checks whether the own terminal is designated as a UL-OFDMA target in the trigger frame (S202). If the own terminal is designated, the resource unit used by the own terminal, and other Know the specified parameters. Further, the control unit 201 of the terminal determines whether to request a delivery confirmation response for a frame transmitted by UL-OFDMA. The control unit 201 of the terminal generates a frame (here, an aggregation frame including a plurality of subframes) based on the presence / absence of a delivery confirmation response request, the grasped parameters, and the like, data read from the buffer, and the like (S203).

  Here, when a delivery confirmation response is requested, the Ack_Policy field of the QoS Control field is set to “00” (Implicit BAR), and when the delivery confirmation response is not required, the Ack_Policy field is set to “11” (Explicit BAR). To do.

  The control unit 201 uses the resource unit specified in the trigger frame to transmit a frame (more specifically, a physical packet including the frame) to a transmission unit after a predetermined time has elapsed since the completion of reception of the trigger frame. It transmits via 202 (S204).

  After transmitting the frame, the control unit 201 of the terminal determines whether a delivery confirmation response frame including a delivery confirmation response for the terminal itself has been received (S205). When an Implicit BAR frame (Ack_policy is “00”) is transmitted, it waits for reception of a delivery confirmation response frame (here, a Multi-STA BA frame) transmitted from the access point after SIFS time.

  When the control unit 201 receives a delivery confirmation response frame including a delivery confirmation response for its own terminal, the control unit 201 confirms the indication flag bit following the AID subfield in which the identifier of the own terminal is set (S206).

  If the bit is “1”, it is determined that the start sequence control subfield and the bitmap field of the own terminal are omitted. Then, with respect to the frame transmitted this time and all frames of the explicit BAR transmitted continuously before the frame transmitted this time, it is determined that transmission of all subframes in these frames was successful (S206).

  On the other hand, if the indication flag bit is “0”, the start sequence number (SSN) is specified from the start sequence control subfield, and the success / failure of transmission for subframes of sequence numbers after SSN is set in the bitmap subfield. It is grasped from the bitmap that has been made (S206).

  As described above, according to the present embodiment, when a frame with Ack_Policy of “00” (Implicit BAR) is received, along with a delivery confirmation response to the frame, Ack_Policy received continuously before that is “11”. "(Explicit BAR) frame acknowledgment response is also returned. As a result, it is possible to prevent the notification of the delivery confirmation response with respect to the explicit BAR frame from being lost. In addition, when the check results of all the frames that should be acknowledged are successful, information indicating that is set to a predetermined bit, and notification of bitmaps and the like is omitted, thereby improving the use of communication resources. it can.

(Second Embodiment)
FIG. 20 shows an example of the overall configuration of a terminal (non-access point terminal) or access point. This configuration example is an example, and the present embodiment is not limited to this. The terminal or access point includes one or more 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 the first embodiment. The wireless LAN module 148 includes a host interface, and is connected to the host system 149 through the host interface. In addition to being connected to the host system 149 via a connection cable, the host system 149 may be directly connected. In addition, a configuration in which the wireless LAN module 148 is mounted on a substrate with solder or the like and is connected to the host system 149 via wiring on the substrate is possible. 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 installed in the wireless LAN module 148, and the host system 149 may execute only higher-layer protocols. In this case, the configuration of the host system 149 can be simplified. This terminal is, for example, a mobile terminal, 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 It may be an adapter, set top box, gateway, printer server, mobile access point, router, enterprise / service provider access point, portable device, handheld device, and the like.

  FIG. 21 shows a hardware configuration example of the wireless LAN module. This configuration can also be applied when the wireless communication apparatus is mounted on either a non-access point terminal or an access point. That is, it can be applied as an example of a specific configuration of the wireless communication apparatus shown in 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, 222-225), a reception system (232-235), a PLL 242, a crystal oscillator (reference signal source) 243, and a switch 245 are arranged corresponding to each antenna. May be connected to the control circuit 212, respectively.

  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 configured by one chip. The DAC 216 and / or the ADC 217 may be disposed on the RF IC 221 or may be disposed on another IC. Further, both or either of the memory 213 and the CPU 215 may be arranged in an IC different from the baseband IC.

  The memory 213 stores data exchanged with the host system. The memory 213 stores information notified to the terminal or access point, information notified from the terminal or access point, or both. The memory 213 may store a program necessary for the execution of the CPU 215 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 SRAM or DRAM, or a nonvolatile memory such as NAND or 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.

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

  At least one of the baseband circuit 212 and the CPU 215 may include 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 adds a physical header, encodes, encrypts, and modulates (may include MIMO modulation) as a physical layer process to a frame to be transmitted. 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 on the signal input from the baseband circuit 212. More specifically, the DAC 216 converts a digital I signal into an analog I signal and converts a digital Q signal into an analog Q signal. Note that there may be a case where the signal is transmitted as it is without any orthogonal modulation. When a plurality of antennas are provided and transmission signals of one system or a plurality of systems are distributed and transmitted by the number of antennas, a number of DACs or the like corresponding to the number of antennas may be provided.

  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) 242, a low noise amplifier (LNA), a balun 235, a mixer 233, and a filter 232. Some of these elements may be located on the 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 in a desired band from each of the analog I signal and the analog Q signal input from the DAC 216. The PLL 242 uses the oscillation signal input from the crystal oscillator 243 and divides and / or multiplies the oscillation signal to generate a signal having a constant frequency synchronized with the phase of the input signal. The PLL 242 includes a VCO (Voltage Controlled Oscillator), and performs feedback control using the VCO based on an oscillation signal input from the crystal oscillator 243, thereby obtaining a signal having the constant frequency. The generated constant frequency signal is input to the mixer 223 and the mixer 233. The PLL 242 corresponds to an example of an oscillator that generates a signal having 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 by using a constant frequency signal supplied from the PLL 242. The preamplifier (PA) 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). Although a balanced signal is handled in the RF IC 221, an unbalanced signal is handled from the output of the RF IC 221 to the antenna 247. Therefore, the balun 225 converts these signals.

  The switch 245 is connected to the transmission-side balun 225 during transmission, and is connected to the reception-side low-noise amplifier (LNA) 234 or the RF IC 221 during reception. The control of the switch 245 may be performed by the baseband IC 211 or the RF IC 221, or another circuit that controls the switch 245 may exist, and the switch 245 may be controlled from the circuit.

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

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

  The LNA 234 in the RF IC 221 amplifies the signal received from the antenna 247 via the switch 245 to a level that can be demodulated while keeping the noise low. The balun 235 performs unbalance-balance conversion on the signal amplified by the low noise amplifier (LNA) 234. A configuration in which the order of the balun 235 and the LNA 234 is reversed may be used. The mixer 233 down-converts the received signal converted into the balanced signal by the balun 235 into a baseband using a signal having a constant frequency input from the PLL 242. More specifically, the mixer 233 has means for generating a carrier wave that is 90 ° out of phase based on a constant frequency signal input from the PLL 242, and the received signals converted by the balun 235 are each 90 ° Quadrature demodulation is performed using a 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 that is delayed by 90 ° therefrom. The filter 232 extracts a signal having a desired frequency component from these I signal and Q signal. The I signal and 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 AD converts the input signal from the RF IC 221. More specifically, the ADC 217 converts the I signal into a digital I signal and converts the Q signal into a digital Q signal. There may be a case where only one system signal is received without performing quadrature demodulation.

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

  Details of the processing of each unit described above are self-evident from the description of FIG. 16 and FIG.

(Third embodiment)
22A and 22B are perspective views of a wireless terminal according to the third embodiment, respectively. The wireless terminal in FIG. 22A is a notebook PC 301, and the wireless terminal in FIG. 22B is a mobile terminal 321. The notebook PC 301 and the mobile terminal 321 are equipped with wireless communication devices 305 and 315, respectively. As the wireless communication devices 305 and 315, the wireless communication device (FIG. 17, FIG. 21, etc.) installed in the wireless terminal described so far, or the wireless communication device (FIG. 16, FIG. 21) installed in the access point 11. Etc.), or both. A wireless terminal equipped with a wireless communication device is not limited to a notebook PC or a mobile terminal. 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 also be installed in printer servers, mobile access points, routers, enterprise / service provider access points, portable devices, handheld devices, and the like.

  Further, the wireless communication device mounted on the wireless terminal or the access point 11 or both can also be mounted on the memory card. FIG. 23 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 a wireless communication device 335 for wireless communication with an external device (such as the wireless terminal and / or the access point 11 or both). In FIG. 23, description of other elements (for example, a memory) in the memory card 331 is omitted.

(Fourth embodiment)
In the fourth embodiment, in addition to the configuration of the wireless communication apparatus (access point wireless communication apparatus and / or wireless terminal wireless communication apparatus, or both) according to the above-described embodiment, a bus, a processor unit, and an external interface A part. The processor unit and the external interface unit are connected to an external memory (buffer) via a bus. Firmware operates in the processor unit. As described above, by configuring the firmware to be included in the wireless communication device, it is possible to easily change the function of the wireless communication device by rewriting the firmware. The processor unit on which the firmware operates may be a 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 and / or the wireless terminal according to the present embodiment may include a processor unit on which firmware operates. Alternatively, the processor unit may be provided in an integrated circuit in a wireless communication device mounted on an access point or an integrated circuit in a wireless communication device mounted on a wireless terminal.

(Fifth embodiment)
In the fifth embodiment, in addition to the configuration of the wireless communication device (access point wireless communication device and / or wireless terminal wireless communication device, or both) according to the above-described embodiment, a clock generation unit is provided. The clock generation unit generates a clock and outputs the clock from the output terminal to the outside of the wireless communication device. Thus, the host side and the wireless communication apparatus side can be operated in synchronization by outputting the clock generated inside the wireless communication apparatus to the outside and operating the host side with the clock output to the outside. It becomes possible.

(Sixth embodiment)
In the sixth embodiment, in addition to the configuration of the wireless communication device (access point wireless communication device or wireless terminal wireless communication device) according to the above-described embodiment, a power supply unit, a power supply control unit, and a wireless power supply unit are provided. Including. The power supply control unit is connected to the power supply unit and the wireless power supply unit, and performs control to select a power supply to be supplied to the wireless communication device. As described above, by providing the wireless communication apparatus with the power supply, it is possible to perform a low power consumption operation by controlling the power supply.

(Seventh embodiment)
The seventh embodiment includes a SIM card in addition to the configuration of the wireless communication apparatus according to the above-described embodiment. The SIM card is connected to a transmission unit (102 or 202), a reception unit (103 or 203), a control unit (101 or 201), or a plurality of these in the wireless communication apparatus. As described above, by adopting a configuration in which the SIM card is provided in the wireless communication device, authentication processing can be easily performed.

(Eighth embodiment)
The eighth embodiment includes a moving image compression / decompression unit in addition to the configuration of the wireless communication apparatus according to the above-described embodiment. The moving image compression / decompression unit is connected to the bus. As described above, by providing the wireless communication device with the moving image compression / decompression unit, it is possible to easily transmit the compressed moving image and expand the received compressed moving image.

(Ninth embodiment)
The ninth embodiment includes an LED unit in addition to the configuration of the wireless communication device (access point wireless communication device or wireless terminal wireless communication device, or both) according to the above-described embodiment. The LED 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 them. In this way, by providing the wireless communication device with the LED unit, it is possible to easily notify the user of the operating state of the wireless communication device.

(Tenth embodiment)
The tenth embodiment includes a vibrator unit in addition to the configuration of the wireless communication device (access point wireless communication device or wireless terminal wireless communication device, or both) according to the above-described embodiment. 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 them. As described above, by providing the radio communication device with the vibrator unit, it is possible to easily notify the user of the operation state of the radio communication device.

(Eleventh embodiment)
In the twelfth embodiment, in addition to the configuration of the wireless communication device (access point wireless communication device or wireless terminal wireless communication device, or both) according to the above-described embodiment, a display is included. The display may be connected to the control unit (101 or 201) of the wireless communication device via a bus (not shown). Thus, it is possible to easily notify the user of the operation state of the wireless communication device by providing the display and displaying the operation state of the wireless communication device on the display.

(Twelfth embodiment)
In this embodiment, [1] a frame type in a wireless communication system, [2] a method of disconnecting connections between wireless communication apparatuses, [3] an access method of a wireless LAN system, and [4] a frame interval of the wireless LAN will be described.
[1] Frame Type in Communication System In general, frames handled on a radio access protocol in a radio 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 portion provided in common between frames. As a display method of the frame type, three types may be distinguished by one field, or may be distinguished by a combination of two fields.

  The management frame is a frame used for managing a physical communication link with another wireless communication apparatus. 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), 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 the other wireless communication device after establishing a physical communication link with the other wireless communication device. Data is generated in an upper layer of the present embodiment, for example, generated by a user operation.

  The control frame is a frame used for control when a data frame is transmitted / received (exchanged) to / from another wireless communication apparatus. When the wireless communication apparatus receives a data frame or a management frame, the response frame transmitted for confirmation of delivery belongs to the control frame.

  These three types of frames are sent out via the antenna as physical packets after undergoing processing as required in the physical layer. In the connection establishment procedure, a connection request frame and a connection acceptance frame are management frames, and a response frame of a control frame can be used as a confirmation frame for the connection acceptance frame.

[2] Methods for disconnecting connections between wireless communication devices There are explicit methods and implicit methods for disconnecting connections. As an explicit method, one of the connected wireless communication apparatuses transmits a frame for disconnection. This frame is classified as a management frame. The frame for disconnection may be called a release frame in the sense that, for example, the connection is released. Usually, the wireless communication device that transmits the release frame determines that the connection is 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, the state of searching for the wireless communication device of the communication partner. This is because when a frame for disconnection is transmitted, a physical radio link may not be secured such that a radio signal cannot be received or decoded due to a communication distance away from the connection destination radio communication device. Because.

  On the other hand, as an implicit method, a frame transmission (transmission of a data frame and a management frame or a response frame to a frame transmitted by the terminal itself) is detected from a wireless communication apparatus of a connection partner that has established a connection for a certain period. If not, it is determined whether the connection is disconnected. There is such a method in the situation where it is determined that the connection is disconnected as described above, such that the communication distance is away from the connection-destination wireless communication device, and the wireless signal cannot be received or decoded. This is because a wireless link cannot be secured. That is, it cannot be expected to receive a release frame.

  As a specific example of determining the disconnection by an implicit method, a timer is used. For example, when transmitting a data frame requesting a delivery confirmation response frame, a first timer (for example, a retransmission timer for a data frame) that limits a retransmission period of the frame is started, and until the first timer expires (that is, If a delivery confirmation response frame is not received (until the desired retransmission period elapses), retransmission is performed. The first timer is stopped when a delivery confirmation response frame to the frame is received.

  On the other hand, when the first timer expires without receiving the delivery confirmation response frame, for example, it is confirmed whether the other party's wireless communication device still exists (within the communication range) (in other words, the wireless link can be secured). And a second timer for limiting the retransmission period of the frame (for example, a retransmission timer for the management frame) is started at the same time. Similar to the first timer, the second timer also performs retransmission if it does not receive an acknowledgment frame for the frame 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 connection partner wireless communication device, the third timer is started. Whenever a new frame is received from the connection partner wireless communication device, the third timer is stopped and restarted from the initial value. When the third timer expires, a management frame is transmitted to confirm whether the other party's wireless communication device still exists (within the communication range) (in other words, whether the wireless link has been secured) as described above. At the same time, a second timer (for example, a retransmission timer for management frames) that limits the retransmission period of the frame is started. Also in this case, if the acknowledgment response frame to the frame is not received until the second timer expires, retransmission is performed, and if the second timer expires, it is determined that the connection has been disconnected. The latter management frame for confirming whether the wireless communication apparatus of the connection partner still exists may be different from the management frame in the former case. In the latter case, the timer for limiting retransmission of the management frame is the same as that in the former case 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 the IEEE802.11 (including extended standards) wireless LAN, CSMA / CA is the basic access method. In the method of grasping the transmission of a certain wireless communication device and performing transmission after a fixed time from the end of the transmission, the transmission is performed simultaneously by a plurality of wireless communication devices grasping the transmission of the wireless communication device, and as a result The radio signal collides and frame transmission fails. By grasping the transmission of a certain wireless communication device and waiting for a random time from the end of the transmission, the transmissions by a plurality of wireless communication devices that grasp the transmission of the wireless communication device are stochastically dispersed. Therefore, if there is one wireless communication device that has drawn the earliest time in the random time, the frame transmission of the wireless communication device is successful, and frame collision can be prevented. Since acquisition of transmission rights is fair among a plurality of wireless communication devices based on a random value, the method employing Carrier Aviation is a method suitable for sharing a wireless medium between 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. The frame interval used in the IEEE 802.11 wireless LAN is as follows: distributed coordination function inter frame space (DIFS), arbitration inter frame speed (IFS), point co-indication frame interface (IFFS), point co-indication frame interface (IFS) There are six types, reduced interface space (RIFS).

  In the IEEE802.11 wireless LAN, the frame interval is defined as a continuous period to be opened after confirming carrier sense idle before transmission, and a strict period from the previous frame is not discussed. Therefore, in the description of the IEEE802.11 wireless LAN system here, the definition follows. In the IEEE802.11 wireless LAN, the time to wait for random access based on CSMA / CA is the sum of a fixed time and a 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 attempting to start frame exchange during a contention period competing with other wireless communication devices based on CSMA / CA. The DIFS is used when priority according to the traffic type (Traffic Identifier: TID) is provided when there is no distinction of the priority according to the traffic type.

  Since operations related to DIFS and AIFS are similar, the following description will be mainly given using AIFS. In the IEEE802.11 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 an upper layer, the 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. This class at the time of access is called an access category (AC). Therefore, an AIFS value is provided for each access category.

  The PIFS is a frame interval for enabling access with priority over other competing wireless communication apparatuses, and has a shorter period than any value of DIFS and AIFS. SIFS is a frame interval that can be used when transmitting a control frame of 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 triggered when frame reception fails.

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

  Here, FIG. 24 shows an example of a frame exchange during a contention period based on random access in the IEEE 802.11 wireless LAN.

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

  The random time is obtained by multiplying a pseudo-random integer derived from a uniform distribution between a contention window (Content Window: CW) given by an integer from 0 to a slot time. Here, CW multiplied by slot time is referred to as 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 reaches CWmax. Both CWmin and CWmax have values for each access category similar to AIFS. When the wireless communication apparatus to which W_DATA1 is transmitted successfully receives the data frame, it transmits a response frame (W_ACK1) after SIFS from the reception end time. The wireless communication apparatus that has transmitted W_DATA1 can transmit the next frame (for example, W_DATA2) after SIFS if W_ACK1 is received and within the transmission burst time limit.

  AIFS, DIFS, PIFS, and EIFS are functions of SIFS and slot time. SIFS and slot time are defined for each physical layer. Also, parameters such as AIFS, CWmin, and CWmax that can be set for each access category can be set for each communication group (Basic Service Set (BSS) in the IEEE802.11 wireless LAN), but default values are set. .

  For example, in the 802.11ac standard formulation, the SIFS is 16 μs and the slot time is 9 μs. Accordingly, the PIFS is 25 μs, the DIFS is 34 μs, and the frame interval of the access category BACKGROUND (AC_BK) in AIFS is 79 μs by default. The frame interval of BEST EFFORT (AC_BE) has a default value of 43 μs, the frame interval of VIDEO (AC_VI) and VOICE (AC_VO) has a default value of 34 μs, and the default values of CWmin and CWmax are 31 and 1023 for AC_BK and AC_BE, respectively. , AC_VI is 15 and 31, and AC_VO is 7 and 15. Note that EIFS is the sum of the time lengths of response frames in the case of transmitting at the slowest required physical rate with SIFS and DIFS. In the present embodiment, a wireless communication system using such a frame interval parameter is assumed as an interference system having a wide communication range.

  Note that the frame described in each embodiment may refer to what is 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 widely. For example, the term “processor” may include general purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), controllers, microcontrollers, state machines, and the like. In some situations, a “processor” may refer to an application specific integrated circuit, a field programmable gate array (FPGA), a programmable logic circuit (PLD), or 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, and one or more microprocessors that cooperate with a DSP core.

  As another example, the term “memory” may encompass any electronic component capable of storing electronic information. “Memory” means random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable PROM (EEPROM), non-volatile It may refer to random access memory (NVRAM), flash memory, magnetic or optical data storage, which can be read by the processor. If the processor reads and / or writes information to the memory, the memory can be said to be in electrical communication with the processor. The memory may be integrated into the processor, which again can 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 the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

11: Access point (base station, wireless communication terminal)
12A, 12B, 12C, 12D: antennas 1, 2, 3, 4, 5, 6, 7, 8: wireless communication terminal 1A: antenna 501: trigger frame 511-514: transmission request frame 521: data frame 531: delivery confirmation Response frames 101 and 201: control unit 102, 202: transmission unit 103, 203: reception unit 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 terminal 331: Memory card 332: Memory card body

Claims (26)

Receiving a plurality of first frames via an RF integrated circuit;
Check whether the plurality of first frames have been successfully received,
If reception of at least one of the plurality of first frames fails, a bit map indicating whether or not each of the plurality of first frames has been successfully received is set in a first field, and the first field exists. Set the first value in the second field to notify whether or not to
If all the first frames are successfully received, the second field is set to a second value, and the second frame in which the first field does not exist is transmitted via the RF integrated circuit. An integrated circuit for wireless communication provided with a baseband integrated circuit. The plurality of first frames are frames obtained by aggregating a plurality of subframes, respectively.
The baseband integrated circuit checks whether the reception of the plurality of subframes in the plurality of first frames is successful;
The integrated circuit for wireless communication according to claim 1, wherein the bit map represents whether or not reception of the plurality of subframes in the plurality of first frames is successful with bits. The first frame received last among the plurality of first frames is a third frame including first information indicating requesting a response to be returned;
The first frame received before the third frame of the plurality of first frames includes second information indicating that it is not required to return the response;
The integrated circuit for wireless communication according to claim 1, wherein the baseband integrated circuit generates the second frame and transmits the second frame when the third frame is received. The baseband integrated circuit receives a fourth frame including first information indicating requesting a response to be returned after the plurality of first frames;
Each of the plurality of first frames includes second information indicating that it is not required to return the response;
The integrated circuit for wireless communication according to claim 1, wherein the baseband integrated circuit generates the second frame and transmits the second frame when the fourth frame is received. The baseband integrated circuit receives a plurality of the first frames to be transmitted by a multiuser a plurality of times,
For each transmission source of the multi-user transmission, the first field can be set in the second frame, and the second field exists.
For a transmission source that fails to receive any of the plurality of first frames received a plurality of times, the bitmap is set in the first field, the first value is set in the second field, and the plurality The wireless communication according to any one of claims 1 to 4, wherein a transmission source that has successfully received all of the first frame is set to a second value in the second field, and the first field is not provided. Integrated circuit. The baseband integrated circuit receives a plurality of the first frames to be transmitted by a multiuser a plurality of times,
The integrated circuit for wireless communication according to any one of claims 1 to 4, wherein the second frame is generated for each transmission source of the multi-user transmission, and the second frame is transmitted. The integrated circuit for wireless communication according to claim 6, wherein the baseband integrated circuit repeatedly transmits a fifth frame that induces the multiuser transmission and receives the plurality of first frames transmitted by the multiuser. . The integrated circuit for wireless communication according to claim 6 or 7, wherein the multi-user transmission includes at least one of OFDMA transmission and MU-MIMO transmission. The integrated circuit for wireless communication according to any one of claims 1 to 8, wherein wireless communication is performed in conformity with the IEEE 802.11 standard. The integrated circuit for wireless communication according to claim 9, wherein the second frame has a format of a Block Ack frame. Further comprising the RF integrated circuit;
The baseband integrated circuit downconverts the first frame from a radio frequency to a baseband frequency;
The RF integrated circuit performs AD conversion on the first frame after down-conversion,
The baseband integrated circuit DA converts the second frame;
The integrated circuit for wireless communication according to any one of claims 1 to 10, wherein the RF integrated circuit upconverts the second frame after DA conversion to a wireless frequency. Further comprising the RF integrated circuit;
The wireless communication integrated circuit according to any one of claims 1 to 11, wherein the baseband integrated circuit and the RF integrated circuit are configured by one integrated circuit. Transmitting a plurality of first frames via an RF integrated circuit;
A baseband integrated circuit for receiving the second frame via the RF integrated circuit;
The second frame includes a second field for notifying whether or not the first frame includes a first field for setting a bit map indicating whether or not reception of the plurality of first frames is successful.
When the first value indicating that the first field is not included is set in the second field, the baseband integrated circuit indicates that all transmissions of the plurality of first frames have been successfully performed. An integrated circuit for wireless communication, comprising: The plurality of first frames are frames obtained by aggregating a plurality of subframes, respectively.
The bitmap is a bitmap in which whether or not the plurality of subframes are successfully received in each of the plurality of first frames is assigned to a bit
The baseband integrated circuit determines that the transmission of the plurality of subframes in each of the plurality of first frames is all successful when the first value is set in the second field. 14. An integrated circuit for wireless communication according to 13. When the second value indicating that the first field is included in the second field is set, the baseband integrated circuit may be configured to use the plurality of baseband integrated circuits based on the bitmap set in the first field. The integrated circuit for wireless communication according to claim 13 or 14, wherein the success or failure of transmission of the first frame is determined. A first frame transmitted last among the plurality of first frames is a third frame including first information indicating requesting a response to be returned;
The first frame transmitted before the third frame among the plurality of first frames includes second information indicating that no response is requested.
An integrated circuit for wireless communication according to any one of claims 13 to 15. The baseband integrated circuit transmits a fourth frame including first information indicating that no response is required to be returned;
Each of the plurality of first frames includes second information indicating that a response is not required to be returned;
The wireless communication integrated circuit according to any one of claims 13 to 15, wherein the baseband integrated circuit receives the second frame after transmitting the fourth frame. The baseband integrated circuit repeatedly receives the fifth frame that induces transmission of the first frame via the RF integrated circuit, and transmits the fifth frame in response to the fifth frame. The integrated circuit for wireless communication according to any one of claims 13 to 17. The integrated circuit for wireless communication according to any one of claims 13 to 18, wherein wireless communication is performed in conformity with the IEEE 802.11 standard. The integrated circuit for wireless communication according to claim 19, wherein the second frame has a format of a Block Ack frame defined by the IEEE 802.11 standard. Further comprising the RF integrated circuit;
The baseband integrated circuit DA converts the first frame,
The RF integrated circuit up-converts the first frame after DA conversion to a radio frequency,
The baseband integrated circuit downconverts the second frame from a radio frequency to a baseband frequency;
The RF integrated circuit performs AD conversion on the second frame after down-conversion.
The integrated circuit for wireless communication according to any one of claims 13 to 20. Further comprising the RF integrated circuit;
The integrated circuit for wireless communication according to any one of claims 13 to 21, wherein the baseband integrated circuit and the RF integrated circuit are configured by one integrated circuit. At least one antenna;
A wireless communication unit connected to the antenna for transmitting and receiving frames;
Receiving a plurality of first frames via the wireless communication unit;
Check whether the plurality of first frames have been successfully received,
If reception of at least one of the plurality of first frames fails, a bit map indicating whether or not each of the plurality of first frames has been successfully received is set in a first field, and the first field exists. Set the first value in the second field to notify whether or not to
When all of the plurality of first frames are successfully received, the second field is set to a second value, and the second frame in which the first field does not exist is transmitted via the wireless communication unit And
Wireless communication terminal equipped with. A wireless communication method using a wireless communication terminal,
Receiving a plurality of first frames;
Check whether the plurality of first frames have been successfully received,
Check whether the plurality of first frames have been successfully received,
If reception of at least one of the plurality of first frames fails, a bit map indicating whether or not each of the plurality of first frames has been successfully received is set in a first field, and the first field exists. Set the first value in the second field to notify whether or not to
If all of the plurality of first frames are successfully received, the second field is set to a second value, and the second frame in which the first field does not exist is transmitted.
A wireless communication method for transmitting. At least one antenna;
A wireless communication unit connected to the antenna for transmitting and receiving frames;
A plurality of first frames are transmitted via the wireless communication unit;
A control unit for receiving the second frame via the wireless communication unit;
The second frame includes a second field for notifying whether or not the first frame includes a first field for setting a bit map indicating whether or not reception of the plurality of first frames is successful.
When the first value indicating that the first field is not included in the second field is set, the control unit determines that all transmissions of the plurality of first frames are successful. Wireless communication terminal. A wireless communication method using a wireless communication terminal,
Send multiple first frames,
After transmitting the plurality of first frames, receiving a second frame;
The second frame includes a second field for notifying whether or not the first frame includes a first field for setting a bit map indicating whether or not reception of the plurality of first frames is successful.
When the first value indicating that the first field is not included in the second field is set, the control unit determines that all transmissions of the plurality of first frames are successful. Wireless communication method.

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