Access point apparatuses and station apparatuses

Abstract

An access point apparatus according to an aspect of the present invention is an access point apparatus for communicating with multiple station apparatuses, the access point apparatus comprising: a transmitter circuitry configured to transmit a trigger frame, wherein the trigger frame includes a User Info field, wherein the User Info field comprises a Resource Unit (RU) Allocation field and a Distributed Bandwidth (Distributed BW) field, wherein the Distributed BW field indicates a Distributed Bandwidth corresponding to 20 MHz, 40 MHz, 60 MHz or 80 MHz over which subcarriers of a distributed resource unit (DRU) are allocated, wherein the DRU is defined as a resource unit in which subcarriers are allocated in a distributed manner across the bandwidth.

Description

[DESCRIPTION][Title of Invention]ACCESS POINT APPARATUSES AND STATION APPARATUSES[Technical Field]

[0001] The present invention relates to an access point apparatus and a station apparatus.[Background Art]

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) has been continuously working on updating of the IEEE 802.11 specification that is a wireless Local Area Network (LAN) standard in order to achieve an increase in speed and frequency efficiency of the wireless LAN network. In recent years, standardization activities for IEEE 802.11 bn have begun, focusing on the theme of achieving Ultra High Reliability (UHR) as standard subsequent to the IEEE 802.11be standard.

[0003] In the standardization activities of IEEE 802.1 lbn, a technology proposed and discussed for specification is Distributed Resource Unit (DRU). A DRU is a type of Resource Unit (RU) that comprises subcarriers distributed across a specific bandwidth, which aims to overcome the regulated Power Spectral Density (PSD) limitations.

[0004] In the context of uplink Orthogonal Frequency-Division Multiple Access (UL-OFDMA) systems, when the Equivalent Isotropic Radiated Power (EIRP) limit is defined per unit bandwidth, DRU effectively boost the transmit power per subcarrier. This enhancement surpasses the capabilities of Regular Resource Unit (RRU), leading to improved throughput and greater reliability in data transmission.[Citation List][Non Patent Literature]

[0005] [Non Patent Literature 1] IEEE 802.11-23 / 0037r0

[0006] [Non Patent Literature 2] IEEE 802.1 l-24 / 0882r2

[0007] [Non Patent Literature 3] IEEE 802.11 -24 / 0801 rl[Brief Description of the Drawings]

[0008] Figure 1 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0009] Figure 2 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0010] Figure 3 is a diagram illustrating an example of communication apparatus according to an aspect of the present invention;

[0011] Figure 4 is an overview diagram illustrating examples of splitting of radio resources according to an aspect of the present invention;

[0012] Figure 5 is a diagram illustrating a configuration example of a communication system according to an aspect of the present invention;

[0013] Figure 6 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0014] Figure 7 is a table illustrating an example of a configuration of control information according to an aspect of the present invention;

[0015] Figure 8 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0016] Figure 9 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0017] Figure 10 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention;

[0018] Figure 11 is a table illustrating an example of a configuration of control information according to an aspect of the present invention;

[0019] Figure 12 is a diagram illustrating an example of resource unit allocation according to an aspect of the present invention;[Description of Embodiments]

[0020] An access point apparatus is described. The access point apparatus comprise: a transmitter circuitry configured to transmit a trigger frame, wherein the trigger frame includes a User Info field, wherein the User Info field comprises a Resource Unit (RU) Allocation field and a Distributed Bandwidth (Distributed BW) field, wherein the Distributed BW field indicates a Distributed Bandwidth corresponding to 20 MHz, 40 MHz, 60 MHz or 80 MHz over which subcarriers of a distributed resource unit (DRU) are allocated, wherein the DRU is defined as a resource unit in which subcarriers are allocated in a distributed manner across the bandwidth.

[0021] The access point apparatus, wherein the trigger frame further includes a Common Info field wherein the signaling information includes: first information, wherein the Common Info field comprises a DRU Indication subfield including a 4-bit bitmap, each bit of the 4-bit bitmap corresponding to a respective 80 MHz frequency segment within a channel bandwidth and indicating whether the corresponding 80 MHz segment is allocated as a DRU or as a regular resource unit (RRU).

[0022] The access point apparatus, wherein when the channel bandwidth comprises fewer than four 80 MHz segments, bits in the DRU Indication subfield corresponding to non-existent segments are reserved and set to 1, and only the bits corresponding toexisting 80 MHz segments are operative to indicate whether the respective segment is allocated as a DRU, represented by a bit value of 0, or as an RRU, represented by a bit value of 1.t

[0023] A station (STA) apparatus is described. The station apparatus comprise: a receiver circuitry configured to receive a trigger frame transmitted by an AP apparatus, wherein the trigger frame includes a User Info field, wherein the User Info field comprises a RU Allocation field and a Distributed BW field, wherein the Distributed BW field indicates a Distributed Bandwidth corresponding to 20 MHz, 40 MHz, 60 MHz or 80 MHz over which subcarriers of a distributed resource unit (DRU) are allocated.

[0024] The STA apparatus, wherein the trigger frame further includes a Common Info field, wherein the Common Info field comprises a DRU Indication subfield including a 4-bit bitmap, each bit of the 4-bit bitmap corresponding to a respective 80 MHz frequency segment within a channel bandwidth and indicating whether the corresponding 80 MHz segment is allocated as a DRU or as a regular resource unit (RRU).

[0025] The STA apparatus, wherein when the channel bandwidth comprises fewer than four 80 MHz segments, bits in the DRU Indication subfield corresponding to nonexistent segments are reserved and set to 1, and only the bits corresponding to existing 80 MHz segments are operative to indicate whether the respective segment is allocated as a DRU, represented by a bit value of 0, or as an RRU, represented by a bit value of 1.

[0026] A communication system according to the present embodiment includes an access point apparatus (or also referred to as a base station, AP STA, or AP apparatus) and a plurality of station apparatuses (or also referred to as terminals, Non-AP STA, or STA apparatuses). The communication system and a network including the access point apparatus and the station apparatus will be referred to as a Basic service set (BSS:management range). In addition, the station apparatus according to the present embodiment can have functions of the access point apparatus. Similarly, the access point apparatus according to the present embodiment can perform the functions of the station apparatus. Therefore, in a case that a wireless communication apparatus is simply mentioned below, the term may denote either the station apparatus or the access point apparatus.

[0027] The base station apparatus and the terminal apparatus in the BSS are assumed to perform communication based on Carrier sense multiple access with collision avoidance (CSMA / CA). Although the present embodiment is intended for an infrastructure mode in which a base station apparatus performs communication with multiple terminal apparatuses, the method of the present embodiment can also be performed in an ad hoc mode in which terminal apparatuses perform communication directly with each other. In the ad hoc mode, the terminal apparatuses substitute the base station apparatus to form a BSS. The BSS in the ad hoc mode will also be referred to as an independent basic service set (IBSS). In the following description, a terminal apparatus that forms an IBSS in the ad hoc mode can also be considered to be a base station apparatus. The method of the present embodiment can also be performed in Wi-Fi Direct (trade name) in which terminal apparatuses directly communicate with each other. In WiFi Direct, the terminal apparatuses form a Group instead of the base station apparatus. Hereinafter, the terminal apparatus as a Group owner forming a Group in Wi-Fi Direct can also be regarded as a base station apparatus.

[0028] In an IEEE 802.11 system, each apparatus can transmit transmission frames of multiple frame types in a common frame format. Each of transmission frames isdefined as a physical (PHY) layer, a medium access control (MAC) layer, and a logical link control (LLC) layer.

[0029] A transmission frame of the PHY layer will be referred to as a physical protocol data unit (PPDU, PHY protocol data unit, or physical layer frame). The PPDU includes the training field (TF) that assist in signal detection, channel estimation and the demodulation process, and other related functions within physical layer; a SIGNAL field containing information used for signal processing in the physical layer; and a physical service data unit (PSDU), representing the processed data unit in the physical layer. The PSDU can include an aggregated MAC protocol data unit (MPDU) (A-MPDU) in which multiple MPDUs serving as retransmission units in a wireless section are aggregated.

[0030] A PHY header includes a reference signal such as a short training field (STF) used for detection, synchronization, and the like of signals, a long training field (LTF) used for obtaining channel information for demodulating data, and the like and a control signal such as a signal (SIG) including control information for demodulating data. In addition, STFs are classified into a legacy-STF (L-STF), a high throughput-STF (HT- STF), a very high throughput-STF (VHT-STF), a high efficiency-STF (HE-STF), an extremely high throughput-STF (EHT-STF), and the like in accordance with corresponding standards, and LTFs and SIGs are also similarly classified into an L-LTF, an HT-LTF, a VHT-LTF, an HE-LTF, an L-SIG, an HT-SIG, a VHT-SIG, an HE-SIG, and an EHT-SIG depending on the corresponding standards. The VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, the HE-SIG is classified into HE-SIG-A1 to 4 and HE-SIG-B. In addition, on the assumption of technology update in the same standard, a universal SIGNAL (U-SIG) field including additional control information can be included.

[0031] Furthermore, the PHY header can include information for identifying a BSS of a transmission source of the transmission frame (hereinafter, also referred to as BSS identification information). The information for identifying a BSS can be, for example, a service set identifier (SSID) of the BSS or a MAC address of a base station apparatus of the BSS. In addition, the information for identifying a BSS can be a value unique to the BSS (e.g., a BSS color, etc.) other than an SSID or a MAC address.

[0032] The PPDU is modulated in accordance with the corresponding standard. In the IEEE 802.1 In standard, for example, the PPDU is modulated into an orthogonal frequency division multiplexing (OFDM) signal.

[0033] An MPDU includes a MAC layer header (MAC header) including header information and the like for performing signal processing in the MAC layer, a MAC service data unit (MSDU) or a frame body that is a data unit processed in the MAC layer, and a frame check sequence (FCS) for checking whether there is an error in a frame (Figure 8). In addition, multiple MSDUs can be aggregated as an Aggregated MSDU (A-MSDU).

[0034] Frame types of a transmission frame of the MAC layer are generally classified into three frame types, namely a management frame for managing a connection state and the like between apparatuses, a control frame for managing a communication state between apparatuses, and a data frame including actual transmission data, and each frame type is further classified into multiple types of subframes. The control frame includes a reception completion notification (Acknowledge or Ack) frame, a transmission request (Request to send or RTS) frame, a reception preparation completion (Clear to send or CTS) frame, and the like. The management frame includes a beacon frame, a probe request frame, a probe response frame, an authentication frame, a connection request(Association request) frame, a connection response (Association response) frame, and the like. The data frame includes a data frame, a polling (CF-poll) frame, and the like. Each apparatus can recognize the frame type and the subframe type of a received frame by interpreting contents of the frame control field included in the MAC header.

[0035] Further, an Ack may include a Block Ack. A Block Ack can give a reception completion notification with respect to multiple MPDUs.

[0036] The beacon frame includes a field in which an interval at which a beacon is transmitted (beacon interval) and an SSID are described. The base station apparatus can periodically broadcast a beacon frame within a BSS, and each terminal apparatus can recognize the base station apparatus in the surroundings of the terminal apparatus by receiving the beacon frame. The action of the terminal apparatus recognizing the base station apparatus based on the beacon frame broadcast from the base station apparatus will be referred to as passive scanning. On the other hand, the action of the terminal apparatus searching for the base station apparatus by broadcasting a probe request frame in the BSS will be referred to as active scanning. The base station apparatus can transmit a probe response frame in response to the probe request frame, and details described in the probe response frame are equivalent to those in the beacon frame.

[0037] The terminal apparatus recognizes the base station apparatus and performs a connection process with respect to the base station apparatus. The connection process is classified into an authentication procedure and a connection (association) procedure. The terminal apparatus transmits an authentication frame (authentication request) to the base station apparatus desiring a connection. Once the base station apparatus receives the authentication frame, then the base station apparatus transmits, to the terminal apparatus, an authentication frame (authentication response) including a status code indicatingwhether authentication can be made for the terminal apparatus. The terminal apparatus can determine whether the terminal apparatus has been authenticated by the base station apparatus by interpreting the status code described in the authentication frame. Further, the base station apparatus and the terminal apparatus can exchange the authentication frame multiple times.

[0038] After the authentication procedure, the terminal apparatus transmits a connection request frame to the base station apparatus in order to perform the connection procedure. Once the base station apparatus receives the connection request frame, the base station apparatus determines whether to allow the connection to the terminal apparatus and transmits a connection response frame to notify the terminal apparatus of the intent. In the connection response frame, an association identifier (AID) for identifying the terminal apparatus is described in addition to the status code indicating whether to perform the connection process. The base station apparatus can manage multiple terminal apparatuses by configuring different AIDs for the terminal apparatuses for which the base station apparatus has allowed connection.

[0039] After the connection process is performed, the base station apparatus and the terminal apparatus perform actual data transmission. In the IEEE 802.11 system, a distributed coordination function (DCF), a point coordination function (PCF), and mechanisms in which the aforementioned mechanisms are enhanced (an enhanced distributed channel access (EDCA) or a hybrid control mechanism (hybrid coordination function (HCF)), and the like) are defined. A case that the base station apparatus transmits signals to the terminal apparatus using the DCF will be described below as an example.

[0040] In the DCF, the base station apparatus and the terminal apparatus perform carrier sensing (CS) for checking usage of a radio channel in the surroundings of theapparatuses prior to communication. For example, in a case that the base station apparatus serving as a transmitting station receives a signal of a higher level than a predefined clear channel assessment level (CCA level) on a radio channel, transmission of transmission frames on the radio channel is postponed. Hereinafter, a state in which a signal of a level that is equal to or higher than the CCA level is detected on the radio channel will be referred to as a busy (Busy) state, and a state in which a signal of a level that is equal to or higher than the CCA level is not detected will be referred to as an idle (Idle) state. In this manner, CS performed based on power of a signal actually received by each apparatus (reception power level) is called physical carrier sense (physical CS). Further, the CCA level is also called a carrier sense level (CS level) or a CCA threshold (CCAT). Further, in a case that a signal of a level that is equal to or higher than the CCA level has been detected, the base station apparatus and the terminal apparatus start to perform an operation of demodulating at least a signal of the PHY layer.

[0041] The base station apparatus performs carrier sensing by an inter-frame space (IFS) in accordance with the type of transmission frame to be transmitted and determines whether the radio channel is busy or idle. A period in which the base station apparatus performs carrier sensing varies depending on the frame type and the subframe type of a transmission frame to be transmitted by the base station apparatus. In the IEEE 802.11 system, multiple IFSs with different periods are defined, and there is a short frame interval (Short IFS or SIFS) used for a transmission frame with the highest priority given, a polling frame interval (PCF IFS or PIFS) used for a transmission frame with a relatively high priority, a distribution control frame interval (DCF IFS or DIFS) used for a transmission frame with the lowest priority, and the like. In a case that the base station apparatus transmits a data frame with the DCF, the base station apparatus uses the DIFS.

[0042] The base station apparatus waits by DIFS and then further waits for a random backoff time to prevent frame collision. In the IEEE 802.11 system, a random backoff time called a contention window (CW) is used. CSMA / CA works with the assumption that a transmission frame transmitted by a certain transmitting station is received by a receiving station in a state in which there is no interference from other transmitting stations. Therefore, in a case that transmitting stations transmit transmission frames at the same timing, the frames collide against each other, and the receiving station cannot receive them properly. Thus, each transmitting station waits for a randomly configured time before starting transmission, and thus collision of frames can be avoided. In a case that the base station apparatus determines, through carrier sensing, that a radio channel is idle, the base station apparatus starts to count down CW, acquires a transmission opportunity (TXOP) for the first time after CW becomes zero, and can transmit the transmission frame to the terminal apparatus. Further, in a case that the base station apparatus determines through the carrier sensing that the radio channel is busy during the count-down of CW, the base station apparatus stops the count-down of CW. In addition, in a case that the radio channel is idle, then the base station apparatus restarts the count¬ down of the remaining CW after the previous IFS.

[0043] Next, details of frame reception will be described. A terminal apparatus that is a receiving station receives a transmission frame, interprets information including the SIGNAL field and other relevant data in accordance with the specifications of the transmission frame, and demodulates the received transmission frame. Then, the terminal apparatus interprets the MAC header of the demodulated signal and thus can recognize whether the transmission frame is addressed to the terminal apparatus itself. Further, the terminal apparatus can also determine the destination of the transmission frame based oninformation described in the SIGNAL field (for example, a group identifier (Group ID or GID) listed in VHT-SIG-A).

[0044] In a case that the terminal apparatus determines that the received transmission frame is addressed to the terminal apparatus and has been able to demodulate the transmission frame without any error, the terminal apparatus has to transmit an ACK frame indicating that the frame has been properly received to the base station apparatus that is the transmitting station. The ACK frame is one of transmission frames with the highest priority transmitted only after a wait for the SIFS period (with no random backoff time). The base station apparatus ends the series of communication with the reception of the ACK frame transmitted from the terminal apparatus. Further, in a case that the terminal apparatus is not able to receive the frame properly, the terminal apparatus does not transmit ACK. Thus, in a case that the ACK frame has not been received from the receiving station for a certain period (a length of SIFS + ACK frame) after the transmission of the frame, the base station apparatus assumes that the communication has failed and ends the communication. In this manner, an end of a single communication operation (also called a burst) in the IEEE 802.11 system must be determined based on whether an ACK frame has been received except for special cases such as a case of transmission of a broadcast signal such as a beacon frame, a case that fragmentation for splitting transmission data is used, or the like.

[0045] In a case that the terminal apparatus determines that the received transmission frame is not addressed to the terminal apparatus itself, the terminal apparatus configures a network allocation vector (NAV) based on the length of the transmission frame described in the PHY header or the like. The terminal apparatus does not attempt communication during the period configured in the NAV. In other words, because theterminal apparatus performs the same operation as in the case that the terminal apparatus determines the radio channel is busy through physical CS for the period configured in the NAV, the communication control based on the NAV is also called virtual carrier sensing (virtual CS). The NAV is also configured by a request to send (RTS) frame or a clear to send (CTS) frame, which are introduced to solve a hidden terminal problem in addition to the case that the NAV is configured based on the information described in the PHY header.

[0046] Unlike the DCF in which each apparatus performs carrier sensing and autonomously acquires the transmission right, with respect to the PCF, a control station called a point coordinator (PC) controls the transmission right of each apparatus within a BSS. In general, the base station apparatus serves as a PC and acquires the transmission right of the terminal apparatus within a BSS.

[0047] A communication period using the PCF includes a contention-free period (CFP) and a contention period (CP). Communication is performed based on the aforementioned DCF during a CP, and a PC controls the transmission right during a CFP. The base station apparatus serving as a PC broadcasts a beacon frame with description of a CFP period (CFP max duration) and the like in a BSS prior to communication with a PCF. Further, the PIFS is used for transmission of the beacon frame broadcast at the time of a start of transmission by the PCF, and the beacon frame is transmitted without waiting for CW. Further, the terminal apparatus that has received the beacon frame configures the CFP period described in the beacon frame in a NAV. Hereinafter, the terminal apparatus can acquire the transmission right only in a case that a signal (e.g., a data frame including CF-poll) for broadcasting the acquisition of the transmission right transmitted by the PC is received until the NAV elapses or a signal (e.g., a data frame including CF-end)broadcasting the end of the CFP in the BSS is received. Further, because no packet collision occurs in the same BSS during the CFP period, each terminal apparatus does not take a random backoff time used for the DCF.

[0048] Orthogonal frequency division multiple access (OFDMA) is an orthogonal frequency division multiple based (OFDM-based) multiple access scheme where different subsets of subcarriers are allocated to different users, and this scheme allows simultaneous data transmission to or from one or more users. In OFDMA, users are allocated different subsets of subcarriers that can change from one PPDU to the next. Similar to OFDM, OFDMA employs multiple subcarriers, but the subcarriers are divided into several groups where each group is referred to as a resource unit (RU). A radio medium can be split into multiple RUs. Figure 4 is an overview diagram illustrating an example of a split state of a radio medium. In the resource splitting example 1, for example, the radio communication apparatus can split a frequency resource (subcarrier) that is a radio medium into nine RUs. Similarly, in a resource splitting example 2, the radio communication apparatus can split a subcarrier that is a radio medium into five RUs. It is a matter of course that the resource splitting examples illustrated in Figure 4 are merely examples, and for example, each of multiple RUs can include a different number of subcarriers. The size of RU is typically specified based on the number of the subcarriers the RU comprises, wherein each subcarrier, also referred to as a "tone", corresponds to a subcarrier in the frequency domain. The present embodiment supports multiple RU sizes, including, but are not limited to 26-tone, 52-tone, 106-tone, 242-tone, 484-tone, and 996- tone RU. For example, a 26-tone RU indicates that it comprises 26 subcarriers within a single resource unit. Moreover, the radio medium that is split into RUs can include not only a frequency resource but also a spatial resource. The radio communication apparatus(e.g., an AP) can transmit frames to multiple terminal apparatuses (e.g., multiple STAs) at the same time by allocating frames addressed to different terminal apparatuses in each RU. An AP can describe information indicating a split state of the radio medium (resource allocation information) as common control information in the PHY header of the frame transmitted by the AP itself. Moreover, the AP can describe information indicating an RU in which a frame addressed to each STA is allocated (resource unit assignment information) as unique control information in the PHY header of the frame transmitted by the AP itself.

[0049] In addition, multiple terminal apparatuses (e.g., multiple STAs) can transmit frames at the same time by allocating and transmitting the frames in the RUs allocated to themselves, respectively. The multiple STAs can perform frame transmission after waiting for a predetermined period after receiving the frame including trigger information transmitted from the AP (trigger frame or TF). Each STA can recognize the RU allocated to the STA itself based on the information described in the TF. In addition, each STA can acquire the RU through random access with reference to the TF.

[0050] The AP can allocate multiple RUs to one STA at the same time. The multiple RUs can include continuous subcarriers or can include discontinuous subcarriers. The AP can transmit one frame using multiple RUs allocated to one STA or can transmit multiple frames after allocating them to different RUs. At least one of the multiple frames can be a frame including common control information for multiple terminal apparatuses that transmit resource allocation information.

[0051] One STA can be allocated multiple RUs by the AP. The STA can transmit one frame using the multiple allocated RUs. Also, the STA can use the multiple allocated RUsto transmit multiple frames allocated to different RUs. The multiple frames can be frames of different types.

[0052] The AP can allocate multiple AIDs to one STA. The AP can allocate an RU to each of the multiple AIDs allocated to the one STA. The AP can transmit different frames using the RUs allocated to the multiple AIDs allocated to the one STA. The different frames can be frames of different types.

[0053] One STA Can be allocated multiple AIDs by the AP. The one STA can be allocated an RU with respect to the multiple allocated AIDs. The one STA recognizes all of the RUs allocated to each of the multiple AIDs allocated to the STA itself as RUs allocated to the STA and can transmit one frame using the multiple allocated RUs. In addition, the one STA can transmit multiple frames using the multiple allocated RUs. At this time, the multiple frames can be transmitted with information indicating the AIDs associated with each of the allocated RUs described therein. The AP can transmit different frames using the RUs allocated to the multiple AIDs allocated to the one STA. The different frames can be frames of different types.

[0054] Hereinafter, the base station apparatus and the terminal apparatuses will be collectively referred to as radio communication apparatuses or communication apparatuses. In addition, information exchanged in a case that a certain radio communication apparatus performs communication with another radio communication apparatus will also be referred to as data. In other words, radio communication apparatuses include a base station apparatus and a terminal apparatus.

[0055] A radio communication apparatus includes any one of or both the function of transmitting a PPDU and a function of receiving a PPDU. Figure 1 is a diagram illustrating examples of configurations of a PPDU transmitted by a radio communicationapparatus. A PPDU that is compliant with the IEEE 802.11 a / b / g standard includes L-STF, L-LTF, L-SIG, and a data frame (a MAC frame, a MAC frame, a payload, a data part, data, information bits, and the like). A PPDU that is compliant with the IEEE 802.1 In standard includes L-STF, L-LTF, L-SIG, HT-SIG, HT-STF, HT-LTF, and a data frame. A PPDU that is compliant with the IEEE 802.1 lac standard includes some or all of L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B, and a MAC frame. A PPDU studied in the IEEE 802.11 ax standard includes some or all of L-STF, L-LTF, L- SIG, RL-SIG in which L-SIG is temporally repeated, HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and a data frame. A PPDU studied in the IEEE 802.11be standard includes some or all of L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, HET-LTF, and a data frame.

[0056] L-STF, L-LTF, and L-SIG surrounded by the dotted line in Figure 1 are configurations commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG will also be collectively referred to as an L-header). For example, a radio communication apparatus that is compliant with the IEEE 802.11 a / b / g standard can appropriately receive an L-header inside a PPDU that is compliant with the IEEE 802.11n / ac standard. A radio communication apparatus that is compliant with the IEEE 802.11 a / b / g standard can receive the PPDU that is compliant with the IEEE 802.11n / ac standard while considering it to be a PPDU that is compliant with the IEEE 802.11 a / b / g standard.

[0057] However, because the radio communication apparatus that is compliant with the IEEE 802.11 a / b / g standard cannot demodulate the PPDU that is compliant with the IEEE 802.11n / ac standard following the L-header, it is not possible to demodulateinformation about a transmitter address (TA), a receiver address (RA), and a duration / ID field used for configuring a NAV.

[0058] As a method for the radio communication apparatus that is compliant with the IEEE 802.1 la / b / g standard to appropriately configure a NAV (or to perform a receiving operation for a prescribed period), IEEE 802.11 defines a method of inserting duration information to the L-SIG. Information about a transmission speed in the L-SIG (a RATE field, an L-RATE field, an L-RATE, an L_DATARATE, and an L_DATARATE field) and information about a transmission period (a LENGTH field, an L-LENGTH field, and an L-LENGTH) are used by the radio communication apparatus that is compliant with the IEEE 802.1 la / b / g standard to appropriately configure a NAV.

[0059] Figure 2 is a diagram illustrating an example of a method for duration information inserted into an L-SIG. Although a PPDU configuration that is compliant with the IEEE 802.1 lac standard is illustrated as an example in Figure 2, a PPDU configuration is not limited thereto. A PPDU configuration that is compliant with the IEEE 802.1 In standard and a PPDU configuration that is compliant with the IEEE 802.11 ax standard may be employed. TXTIME includes information about a length of a PPDU, aPreambleLength includes information about a length of a preamble (L-STF + L-LTF), and aPLCPHeaderLength includes information about a length of a PLCP header (L-SIG). L_LENGTH is calculated based on Signal Extension that is a virtual period configured for compatibility with the IEEE 802.11 standard, Nopsrelated to L-RATE, aSymbolLength that is information about one symbol (a symbol, an OFDM symbol, or the like), aPLCPServiceLength indicating the number of bits included in PLCP Service field, and aPLCPConvolutionalTailLength indicating the number of tail bits of a convolution code. The radio communication apparatus can calculate L_LENGTH andinsert L_LENGTH into L-SIG. In addition, the radio communication apparatus can calculate L-SIG Duration. L-SIG Duration indicates information about a PPDU including L_LENGTH and information about a period that is the sum of periods of Ack and SIFS expected to be transmitted by the destination radio communication apparatus in response to the PPDU.

[0060] Figure 3 is a diagram illustrating an example of L-SIG Duration in L-SIG TXOP Protection. DATA (a frame, a payload, data, and the like) include some of or both the MAC frame and the PLCP header. In addition, BA includes Block Ack or Ack. A PPDU includes L-STF, L-LTF, and L-SIG and can further include any one or more of DATA, BA, RTS, or CTS. Although L-SIG TXOP Protection using RTS / CTS is illustrated in the example illustrated in Figure 3, CTS-to-Self may be used. Here, MAC Duration is a period indicated by a value of Duration / ID field. Furthermore, Initiator can transmit a CF_End frame for providing a notification regarding an end of the L-SIG TXOP Protection period.

[0061] Next, a method of identifying a BSS from a frame received by a radio communication apparatus will be described. In order for a radio communication apparatus to identify a BSS from a received frame, the radio communication apparatus that transmits a PPDU preferably inserts information for identifying the BSS (BSS color, BSS identification information, or a value unique to the BSS) into the PPDU. The information indicating the BSS color can be described in HE-SIG-A.

[0062] The radio communication apparatus can transmit L-SIG multiple times (L-SIG Repetition). For example, demodulation accuracy of L-SIG is improved by the radio communication apparatus on the reception side receiving L-SIG transmitted multiple times by using Maximum Ratio Combining (MRC). Moreover, in a case that reception ofL-SIG has been properly completed using MRC, the radio communication apparatus can interpret the PPDU including the L-SIG as a PPDU that is compliant with the IEEE 802.11 ax standard.

[0063] Even during the operation of receiving the PPDU, the radio communication apparatus can perform an operation of receiving part of a PPDU other than the corresponding PPDU (e.g., the preamble, L-STF, L-LTF, and the PLCP header prescribed by IEEE 802.11) (also referred to as a double-reception operation). In a case that a part of a PPDU other than the PPDU is detected during the operation of receiving the PPDU, the radio communication apparatus can update a part or an entirety of information about a destination address, a transmission source address, a PPDU, or a DATA period.

[0064] An Ack and a BA can also be referred to as a response (response frame). In addition, a probe response, an authentication response, and a connection response can also be referred to as a response.

[0065] An embodiment of this invention will be described below, which is performed in a BSS consisting of two communication apparatus, a STA apparatus and an AP apparatus, which have the same configuration as the wireless communication apparatus 500 in Figure 5. However, the number of wireless communication apparatuses (STA apparatuses or AP apparatuses) in the BSS may be three or more. The BSS also includes a wireless communication apparatus (also called UHR STA) that is compliant with the IEEE802.11bn standard or the next-generation standard of IEEE802.11bn, and in this embodiment, at least the STA apparatus and the AP apparatus are included.

[0066] The wireless communication apparatus, when transmitting under power spectral density (PSD) limitations, allocates subcarriers of RU in distributed manner across the bandwidth

[0067] to enhance transmit power per subcarrier. This technique is referred to as distributed resource unit (DRU). An example of DRU is illustrated in Figure 12. In the figure, each single block (e.g., a block with striped lines) represents one subcarrier, also referred to as a tone, in the frequency domain. The regular resource unit (RRU) is defined as a RU in which the subcarriers within the same RU are allocated contiguously, meaning the tones are adjacent to one another within the frequency domain. In contrast, the DRU distributes is defined as a RU in which the subcarriers within the same RU are allocated in a non-contiguous, interleaved, or otherwise distributed manner across a wider channel bandwidth. It should be noted that the figure is provided as an example, and the number of tones for a single RRU or DRU is not limited to three. The number of tones for one RRU or DRU may also be 26, 52, 106, 242, 484, 996, or any other value, depending on the system configuration. The STA apparatus, when transmitting using DRU, allocates subcarriers in a distributed manner across a wider bandwidth rather than in contiguous blocks as in a regular resource unit (RRU). The AP apparatus, when receiving transmissions from the STA apparatus employing distributed subcarriers, benefits from enhanced transmission power. This method of increasing spectral efficiency while adhering to PSD regulations.

[0068] The STA apparatus and the AP apparatus are configured to transmit signaling information to each other through a signaling information circuitry. Signaling information refers to the data exchanged between wireless communication apparatuses to perform operations, including, but not limited to, establishing, maintaining, modifying, and terminating communication sessions. The signaling information encompasses control and management messages that enable apparatuses to coordinate their actions.

[0069] Signaling information is typically included in a trigger frame, which serves as a specialized control frame in wireless communication systems. The trigger frame is transmitted by the AP apparatus to coordinate uplink transmissions from one or more STA apparatuses. The trigger frame includes a plurality of fields, which may include, but are not limited to, Common Info field and User Info List. Common Info field is shared among all recipient STAs and may specify parameters such as Trigger Type, UL Length, and channel bandwidth. The User Info List field comprises a plurality of User Info fields, each of which includes information specific to an individual STA. The User Info field may contain parameters such as AID 12, Resource Unit (RU) Allocation, ULFEC Coding Type. An example of the trigger frame format is illustrated in Figure 6.

[0070] When the STA apparatus performs a connection process with the AP apparatus, it transmits a connection request frame. When the AP apparatus receives the connection request frame, it determines whether to permit a connection with the STA apparatus, and transmits a connection response frame to notify the determination. The connection request frame and the connection response frame include a field indicating the capability information of the wireless communication apparatus that is the sender.

[0071] The capability information indicating Tx DRU Supported information, Rx DRU Supported information, or both, included in any of the fields in the connection response frame is also called DRU Supported information. The value of the subfield indicating DRU Supported information allows the STA apparatus to know whether DRU is applicable when transmitting data to the AP apparatus. In this embodiment, as an example, when the value of the subfield indicating DRU Supported information is 1 , DRU is applicable for both transmission and reception. It is also possible to indicate that transmission is possible with DRU and reception is possible with DRU, depending on thevalue of the subfield indicating DRU Supported information. Similarly, the AP apparatus can know whether DRU is applicable to the STA apparatus based on the DRU Supported information included in the connection request frame transmitted by the STA apparatus. In addition, since similar capability information is also included in beacon frames, probe request frames, probe response frames, etc., wireless communication apparatuses may obtain each other's DRU Supported information by transmitting and receiving these frames.

[0072] When the values of the subfield indicating the DRU Supported information of the STA apparatus and the AP apparatus are both 1 , the signaling information in the trigger frame generated and transmitted by the AP apparatus, contains signaling information related to DRU. An example of transmission and reception of trigger frame when DRU is applicable will be described. The trigger frame consists of a Common Info field and a User Info List field. Common Info field is independent of the destination wireless communication apparatus. Specifically, the Common Info field is configured to include some or all of the elements indicating control information such as Trigger Type, UL BW and DRU Indication. The Trigger Type subfield identifies the Trigger frame variant. The UL BW subfield of the Common Info field indicates the bandwidth in the HE-SIG-A (or U-SIG) of the PPDU and is defined in Figure 7. The information relating to the UL BW is herein referred to as third information. The DRU Indication subfield of the Common Info field is configured to indicate the type of RU. Specifically, the DRU Indication subfield comprises a 4-bit bitmap, where each bit corresponds to an 80 MHz segment within the channel bandwidth. Each bit is set to a value indicating whether the corresponding 80 MHz segment is allocated for DRU or RRU. In this embodiment, as an example, all the 80 MHz segments are indicated as DRU by setting each bit in the 4-bitbitmap to a value representing the DRU allocation. In practice, if the channel bandwidth does not include all four 80 MHz segments (for example, in 20, 40, 80, or 160 MHz modes), the bits corresponding to non-existent segments may be treated as reserved and set to 1, and only bits for valid segments are used, with 0 indicating DRU.

[0073] The User Info List field contains zero or more User Info fields. Specifically, the User Info field is configured to include at least elements indicating control information such as RU Allocation and Distributed BW, wherein the RU Allocation refers to an allocation of the RU. The information relating to the RU Allocation is herein referred to as first information. The RU Allocation subfield in User Info field along with the UL BW subfield in the Common Info field identifies the size and the location (also called index) of the RU. If the UL BW subfield indicates 20 MHz, 40 MHz or 80 MHz, then B0 of the RU Allocation subfield is set to 0 (B0 represents the first bit of the RU Allocation subfield). If the UL BW subfield indicates 80+80 MHz or 160 MHz, then B0 of the RU Allocation subfield is set to 0 to indicate that the RU allocation applies to the primary 80 MHz channel and is set to 1 to indicate that the RU allocation applies to the secondary 80 MHz channel. The Distributed BW subfield in User Info field indicates the bandwidth refers to the allocation of subcarriers across the entire available channel bandwidth. This bandwidth, also referred to as Distributed Bandwidth (DBW), corresponds to a channel width of 20, 40, 60 or 80 MHz over which the subcarriers of a DRU are allocated.

[0074] Length of RU Allocation for a STA apparatus is determined based on a size of the RU included in the User Info field. Specifically, upon receiving a trigger Frame transmitted by the AP apparatus, the STA apparatus reads the signaling information comprising RU Allocation subfield from the User Info field. By interpreting the subfield, the STA apparatus identifies the specific subcarriers across the channel bandwidth thatare allocated for its use. Similar to RU Allocation, DRU Allocation indicates the location of the RU when DRU is applicable. An allocation of the DRU for the STA apparatus is determined based on the signaling information comprising the DRU Allocation, the size of the RU, and the Distributed BW subfield included in the User Info field. By way of example, the length of the information relating to the DRU Allocation may be determined based on the signaling information comprising the size of the RU and the UL BW. However, the determination is not limited to the length. Upon receiving a trigger Frame transmitted by the AP apparatus, the STA apparatus reads the DRU Allocation, the RU size and the Distributed BW subfield from the User Info field. By interpreting these subfields, the STA apparatus identifies the specific subcarriers across the channel bandwidth that are allocated for its use.

[0075] An example will also be provided to explain the Common Info field and User Info List field in the trigger frame in trigger frame-based transmission, and further includes variable-length control information related to the DRU depending on the conditions.

[0076] For example, the Common Info field in the trigger frame includes at least Trigger Type, UL BW, and DRU Indication information as illustrated in Figure 9. The User Info field, included in the User Info List field of trigger frame includes at least RU Allocation and Distributed BW information as illustrated in Figure 10. The RU Allocation subfield is composed of B0, RU size, and DRU Allocation. B0 represents the first bit of the RU Allocation subfield and is used to indicate whether the RU allocation applies to the primary 80 MHz channel (B0 = 0) or the secondary 80 MHz channel (B0 = 1) in configurations with 80+80 MHz or 160 MHz bandwidth. The RU size indicates a size of the RU, wherein the size corresponds to the number of subcarriers (or tones) within asingle RU. The information relating to the RU size is herein referred to as second information. The RU size is represented by 2 bits in the RU Allocation subfield. The interpretation of the 2 bits varies based on the value of UL BW subfield in the Common Info field. However, the number of bits used to represent the RU size is not limited to 2 bits and may also be 1, 3, 4, 5, 6, 7, 8, or any other number of bits. For example, as illustrated in Figure 11, when the value of the UL BW subfield in the Common Info field is 0, indicating a bandwidth of 20 MHz, the 2 bits in the RU size of the RU Allocation subfield within the User Info field are interpreted as follows: 00 indicates 26-tone, 01 indicates 52-tone, and 10 indicates 106-tone. When the value of the UL BW subfield in the Common Info field is 1, indicating a bandwidth of 40 MHz, the 2 bits in the RU size of the RU Allocation subfield within the User Info field are interpreted as follows: 00 indicates 26-tone, 01 indicates 52-tone, 10 indicates 106-tone and 11 indicates 242-tone. When the value of the UL BW subfield in the Common Info field is 2, indicating a bandwidth of 80 MHz, the 2 bits in the RU size of the RU Allocation subfield within the User Info field are interpreted as follows: 00 indicates 52-tone, 01 indicates 106-tone, 10 indicates 242-tone and 11 indicates 484-tone. When the value of the UL BW subfield in the Common Info field is 3, indicating a bandwidth of 80 + 80 MHz or 160 MHz, the 2 bits in the RU size of the RU Allocation subfield within the User Info field are interpreted as follows: 00 indicates 106-tone, 01 indicates 242-tone, 10 indicates 484-tone and 11 indicates 996-tone.

[0077] Furthermore, the DRU Allocation included in the RU Allocation subfield indicates the location of the RU when DRU is applicable. The information relating to the DRU Allocation is herein referred to as fourth information. Length of the DRU Allocation in the RU Allocation subfield is dependent on the value of the RU size included withinthe same RU Allocation subfield of the User Info field, and the value of UL BW subfield in the Common Info field, an example illustrated in Figure 11. Specifically, when the value of the UL BW subfield in the Common Info field is 0, indicating a bandwidth of 20 MHz, and the value of RU size in the User Info field is 00, indicating an RU size of 26-tone, the length of DRU Allocation in the same RU Allocation subfield is configured to be 4 bits. The non-AP station (STA) apparatus, comprises a receiver circuitry configured to receive a trigger frame from the AP apparatus, the trigger frame including signaling information that comprises information regarding the RU Allocation. The non-AP station (STA) apparatus further comprises a processing circuitry configured to interpret the signaling information that comprises information regarding the RU Allocation based on the relationship illustrated in Figure 11 , determine the location of the RU for transmission to the AP apparatus, and allocate the RU based on the RU Allocation. However, the correspondence among UL BW, RU size, and DRU Allocation is not limited to the format shown in Figure 11.

[0078] Although the communication apparatuses according to the present invention can perform communication in a frequency band (frequency spectrum) that is a so-called unlicensed band that does not require permission to use from a country or a region, available frequency bands are not limited thereto. The communication apparatus according to the present invention can exhibit its effect in a frequency band called a white band, which is actually not used for the purpose of preventing frequency jamming regardless of a nation or a region allowing utilization thereof for a specific service (for example, a frequency band allocated for television broadcasting or a frequency band which is not used depending on regions), or a shared spectrum (shared frequency band) which is expected to be shared by a plurality of service providers, for example.

[0079] A program that operates in the radio communication apparatus according to the present invention is a program (a program for causing a computer to function) for controlling the CPU or the like to implement the functions of the aforementioned embodiments related to the present invention. In addition, information handled by these apparatuses is temporarily accumulated in a RAM at the time of processing, is then stored in various types of ROMs and HDDs, and is read by the CPU as necessary to be corrected and written. A semiconductor medium (e.g., a ROM, a non-volatile memory card, etc.), an optical recording medium (e.g., a DVD, an MO, an MD, a CD, a BD, etc.), a magnetic recording medium (e.g., a magnetic tape, a flexible disk, etc.), and the like can be examples of recording media for storing programs. In addition to implementing the functions of the aforementioned embodiments by performing loaded programs, the functions of the present invention are implemented in processing performed in cooperation of an operating system, other application programs, and the like based on instructions of those programs.

[0080] In a case of delivering these programs to market, the programs can be stored and distributed in a portable recording medium, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device serving as the server computer is also included in the present invention. In addition, a part or an entirety of the communication apparatuses in the aforementioned embodiments may be implemented as an LSI that is typically an integrated circuit. The functional blocks of the communication apparatuses may be individually implemented as chips or may be partially or completely integrated into a chip. In a case that the functional blocks are made as integrated circuits, an integrated circuit controller for controlling them is added.

[0081] In addition, the circuit integration technique is not limited to LSI, and may be realized as dedicated circuits or a multi-purpose processor. Moreover, in a case that a circuit integration technology that substitutes an LSI appears with the advance of the semiconductor technology, it is also possible to use an integrated circuit based on the technology.

[0082] Note that, the invention of the present application is not limited to the abovedescribed embodiments. The radio communication apparatus according to the invention of the present application is not limited to the application in the mobile station apparatus, and, needless to say, can be applied to a fixed-type electronic apparatus installed indoors or outdoors, or a stationary-type electronic apparatus, for example, an AV apparatus, a kitchen apparatus, a cleaning or washing machine, an air-conditioning apparatus, office equipment, a vending machine, and other household apparatuses.

[0083] Although the embodiments of the invention have been described in detail above with reference to the drawings, a specific configuration is not limited to the embodiments, and designs and the like that do not depart from the essential spirit of the invention also fall within the claims.

Claims

[CLAIMS]1. An access point (AP) apparatus comprising:a transmitter circuitry configured to transmit a trigger frame,wherein the trigger frame includes a User Info field,whereinthe User Info field comprises a Resource Unit (RU) Allocation field and a Distributed Bandwidth (Distributed BW) field,whereinthe Distributed BW field indicates a Distributed Bandwidth corresponding to 20 MHz, 40 MHz, 60 MHz or 80 MHz over which subcarriers of a distributed resource unit (DRU) are allocated,whereinthe DRU is defined as a resource unit in which subcarriers are allocated in a distributed manner across the bandwidth.

2. The AP apparatus of claim 1, whereinthe trigger frame further includes a Common Info field,whereinthe Common Info field comprises a DRU Indication subfield including a 4-bit bitmap, each bit of the 4-bit bitmap corresponding to a respective 80 MHz frequency segment within a channel bandwidth and indicating whether the corresponding 80 MHz segment is allocated as a DRU or as a regular resource unit (RRU),whereinthe RRU is defined as a resource unit in which subcarriers are allocated contiguously within the bandwidth.

3. The AP apparatus of claim 2, whereinwhen the channel bandwidth comprises fewer than four 80 MHz segments, bits in the DRU Indication subfield corresponding to non-existent segments are reserved and set to 1, andonly the bits corresponding to existing 80 MHz segments are operative to indicate whether the respective segment is allocated as a DRU, represented by a bit value of 0, or as an RRU, represented by a bit value of 1.

4. A station (STA) apparatus comprising : :a receiver circuitry configured to receive a trigger frame transmitted by an AP apparatus,wherein the trigger frame includes a User Info field,whereinthe User Info field comprises a RU Allocation field and a Distributed BW field, whereinthe Distributed BW field indicates a Distributed Bandwidth corresponding to 20 MHz, 40 MHz, 60 MHz or 80 MHz over which subcarriers of a distributed resource unit (DRU) are allocated.

5. The STA apparatus of claim 4, whereinthe trigger frame further includes a Common Info field,whereinthe Common Info field comprises a DRU Indication subfield including a 4-bit bitmap, each bit of the 4-bit bitmap corresponding to a respective 80 MHz frequency segment within a channel bandwidth and indicating whether the corresponding 80 MHz segment is allocated as a DRU or as a regular resource unit (RRU).

6. The STA apparatus of claim 5, whereinwhen the channel bandwidth comprises fewer than four 80 MHz segments, bits in the DRU Indication subfield corresponding to non-existent segments are reserved and set to 1, andonly the bits corresponding to existing 80 MHz segments are operative to indicate whether the respective segment is allocated as a DRU, represented by a bit value of 0, or as an RRU, represented by a bit value of 1.

Images