COMMUNICATION APPARATUS AND COMMUNICATION METHOD FOR MULTIPLE-USER UPLINK TRANSMISSION FROM ACTIVATOR BASE

Abstract

The present description provides a communication apparatus and method for multi-user uplink transmission of a base activator. A communication apparatus is provided, the communication apparatus comprising: a circuit set, which in operation generates an activator frame comprising a common information field and a plurality of user information fields; and a transmitter, which in operation transmits the generated activator frame; wherein each of the plurality of user information fields comprises a first field indicating whether a resource unit (RU) adaptation procedure is disabled for another communication apparatus directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the other communication apparatus.

Description

This description refers to communication devices and methods for multi-user uplink transmission, and more specifically, to communication devices and methods for multi-user uplink transmission from the activator base. Background of the Invention In the standardization of a next-generation wireless local area network (WLAN), a new radio access technology that has backward compatibility with IEEE 802.11 a / b / g / n / ac / ax technologies has been discussed in the IEEE 802.11 working group and is named an extremely high-performance (EHT) 802.libe WLAN. In IEEE 802.lib EHT WLAN, with the purpose of improving spectral efficiency compared to High Efficiency (HE) 11ax WLAN, it is proposed to increase the maximum channel bandwidth to 320 MHz and to allow more Resource Units (RUs) to be distributed to a single Station (STA). Ref. 340242 (its acronym in English). However, there is not much discussion about efficient multi-user uplink transmission from a trigger base with a bandwidth of up to 320 MHz. Thus, there is a need for communication devices and methods that provide feasible technical solutions for the efficient transmission of multiple users via an uplink trigger base with a bandwidth of up to 320 MHz. Furthermore, other desirable configurations and features will become clear from the following detailed description and the accompanying claims, taken in conjunction with the accompanying figures and background information. Summary of the Invention The non-limiting and exemplary modalities facilitate the provision of communication devices and communication methods for the efficient transmission of multiple users of activator base uplink. According to a first aspect, the present description refers to a communication apparatus comprising: a set of circuits, which in operation, generates an activator frame comprising a common information field and a plurality of user information fields; and a transmitter, which in operation, transmits the generated activator frame; wherein each of the plurality of user information fields comprises a first field indicating whether a resource unit (RU) adaptation procedure is deactivated for another communication apparatus directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the other communication apparatus. According to a second aspect, the present description refers to a communication method comprising: generating an activator frame comprising a common information field and a plurality of user information fields; and transmitting the generated activator frame; wherein each of the plurality of user information fields comprises a first field indicating whether a RU adaptation procedure is deactivated for a communication device directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the communication device. It should be noted that the general or specific modalities could be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selected combination thereof. The additional benefits and advantages of the described modalities will be clear from the description and figures. These benefits and / or advantages could be obtained individually through the various modalities and features described and illustrated; not all of these features need to be provided to obtain one or more of these benefits and / or advantages. Brief Description of the Figures The descriptive methods will be better understood and more easily comprehensible to a person of ordinary experience in the technique from the following written description, solely by means of examples and in conjunction with the figures, in which: Figure 1A shows a schematic diagram of trigger-base uplink multi-user (MU) communication between an AP and multiple STAs in a MIMO wireless network. Figure IB shows an EHT Activator Base (TB) Physical Layer Protocol Data Unit (PPDU). Figure 1C shows a diagram illustrating how the pre-EHT modulated fields of an EHT TB PPDU could be transmitted with a bandwidth of 320 MHz. Figure ID shows a table of fields performed in a U-SIG field of an EHT TB PPDU. Figure 2 shows an illustration of a MA / a / ZUZJ / UUUT ÓZ MU uplink transmission of 802.11ax type activator base. Figure 3 shows a table illustrating a RU or RU combination larger than 242 tones and the associated RUs or RU combinations according to various modalities. Figure 4 shows a format of a basic EHT activator box according to various modalities. Figure 5 shows an illustration of how RU adaptation is achieved according to various modalities. Figure 6 shows a flowchart illustrating an EHT TB PPDU transmission procedure according to a first mode. Figure 7 shows a flowchart illustrating an EHT TB PPDU receiving procedure according to a first modality. Figure 8 shows a table of fields made in a U-SIG field of an EHT TB PPDU transmitted by an STA with the RU adaptation field disabled in the STA user information field requesting the basic EHT activator box set to 0 under option A according to a second mode. Figures 9A-9C show a table illustrating how the RU or RU combination distributed larger than 242 tones and the adapted RU distribution field indicate an RU or RU combination adapted under option A according to a MA / a / ZUZJ / UUUl ÓZ MA / a / ZUZJ / UUUl second modality. Figure 10 shows a diagram illustrating how RU adaptation is achieved according to a second modality. Figure 11 shows a flowchart illustrating an EHT TB PPDU receiving procedure according to a second modality. Figure 12 shows a flowchart illustrating an EHT TB PPDU transmission procedure according to a third mode. Figure 13 shows a format of a basic EHT activator box according to a third modality. Figure 14 shows a table illustrating the number of blind decodings required for each of the RUs or distributed RU combinations larger than 242 tones according to a third modality. Figure 15 shows a flowchart illustrating an EHT TB PPDU reception according to a third modality. Figure 16 shows a flowchart illustrating a method for implementing multi-user uplink trigger base transmission according to various modalities. Figure 17 shows a schematic, partially sectioned view of a communication device that MA / a / ZUZJ / UUUl can be implemented for multi-user uplink transmission from trigger base according to various modalities. Experts will appreciate that the elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the illustrations, block diagrams, or flowcharts may be exaggerated relative to other elements to aid in a precise understanding of the present modalities. Detailed Description of the Invention Some aspects of this description will be illustrated, by example only, with reference to the figures. The same numbers and reference characters in the figures refer to the same elements or their equivalents. In the following paragraphs, certain example modalities are explained with reference to an access point (AP) and a station (STA) for the transmission of multiple uplink users, especially in a wireless multiple-input multiple-output (MIMO) network. In the context of IEEE 802.11 (Wi-Fi) technologies, a station, which is referred to interchangeably as an STA, is a communication device that has the ability to use the protocol 802.11. Based on the IEEE 802.112016 protocol definition, an STA can be any device that contains an IEEE 802.11 protocol, a Media Access Control (MAC) protocol, and a Physical Layer (PHY) that interconnects with the Wireless Medium (WM). For example, an STA could be a laptop computer, a desktop PC, a personal digital assistant (PDA), an access point, or a Wi-Fi phone in a wireless local area network (WLAN) environment. The STA could be fixed or mobile. In a WLAN environment, the terms STA, wireless client, user, user device, and node are often used interchangeably. Similarly, an AP, which could also be referred to interchangeably as a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technologies, is a communication device that allows STAs in a WLAN to connect to a wired network. Typically, the AP connects to a router (via a wired network) as a standalone device, although it can also be integrated with or used within the router. As mentioned previously, an STA in a WLAN could function as an AP on a different occasion and ML / a / ZUZJ / UUU IÓZ MA / a / ZUZJ / UUUl and vice versa. This is because communication devices in the context of IEEE 802.11 (Wi-Fi) technologies may include both STA hardware components and AP hardware components. Thus, the communication device may switch between STA mode and AP mode, depending on the current WLAN conditions and / or requirements. In a MIMO wireless network, the term "multiple" refers to multiple antennas used simultaneously for transmission and multiple antennas used simultaneously for reception over a single radio channel. In this context, the term "multiple inputs" refers to multiple transmitting antennas that send a radio signal into the channel, and the term "multiple outputs" refers to multiple receiving antennas that receive the radio signal from the channel and send it to the receiver. For example, in an N x M MIMO network system, N is the number of transmitting antennas, M is the number of receiving antennas, and N may or may not be equal to M. For simplicity, the respective numbers of transmitting and receiving antennas are not discussed further in this description. In a MIMO wireless network, multi-user (MU) communications can be deployed for communication between devices such as access points (APs) and station access points (STAs). MIMO wireless networks offer benefits such as spatial multiplexing and spatial diversity, which enable higher data rates and increased robustness through the use of multiple spatial streams or transmissions. In some models, the term "spatial stream" may be used interchangeably with "spacetime stream" (STS). To enable MU uplink transmissions, trigger base communication is provided to the MIMO wireless network. In this regard, Figure 1A shows a schematic diagram 100 of the trigger base MU uplink communication between an AP 102 and the multiple STAs 104, 106, 108 in a MIMO wireless network. Because there are multiple STA 104, 106, 108 participating in the trigger base uplink MU communication, AP 102 needs to coordinate the simultaneous transmissions of the multiple STA 104, 106, 108. To do this, as shown in Figure 1A, AP 102 transmits trigger frames 110, 112, and 114 simultaneously to STAs 104, 106, and 108 to indicate user-specific resource allocation information (e.g., the number of space-time flows, an STS start number, and the distributed Ru) that each STA can use. In response to the trigger frames, STAs 104, 106, and 108 could then transmit their respective space-time flows simultaneously to AP 102 according to the MA / a / ZUZJ / UUUl ÓZ MA / a / ZUZJ / UUUl User-specific resource allocation information indicated in trigger boxes 110, 112, 114. For example, two space-time streams could be directed to AP 102 of STA 106, another space-time stream could be directed to AP 102 of STA 104, and yet another space-time stream could be directed to AP 102 of STA 108. For simplicity, the two space-time streams directed to AP 102 of STA 106 are illustrated as a grouped data transmission arrow 118, the space-time stream directed to AP 102 of STA 104 is illustrated as a data transmission arrow 116, and the space-time stream directed to AP 102 of STA 108 is illustrated as a data transmission arrow 120. Figure IB shows an example EHT trigger base physical layer protocol data unit (TB) 122 (PPDU), which could be transmitted as a transmit signal by means of a communication device (such as an STA) to another communication device (such as an AP) in a trigger base communication.The EHT TB PPDU 122 could include pre-EHT modulated fields such as a short non-high-performance training field (L-STF), a long non-high-performance training field (L-LTF), a non-high-performance signal field (L-SIG), a repeated L-SIG field (RL-SIG), and a universal signal field (U-SIG) 124, as well as EHT modulated fields such as an EHT short training field (EHT-STF), an EHT long training field (EHT-LTF), a data field, and a packet extension (PE) field. The REI L-SIG field is primarily used to identify any type of PHY version beginning with 802.libe. The U-SIG 124 field could contain the information necessary to interpret the EHT modulated fields and to coexist with third-party STAs. Figure 1C shows a diagram 126 illustrating how the pre-EHT modulated fields of an EHT TB PPDU with a bandwidth of 320 MHz could be transmitted. The 320 MHz bandwidth is divided into four 80 MHz frequency segments. In addition, each 80 MHz frequency segment is also divided into four 20 MHz frequency segments. Each row in diagram 126 represents a 20 MHz frequency segment in which the pre-EHT modulated fields (i.e., L-STF, L-LTF, L-SIG, REI L-SIG, and U-SIG) of the EHT TB PPDU are transmitted. The transmitted L-SIG and REI L-SIG fields could be the same for all 20 MHz frequency segments, although the U-SIG field could differ between the 80 MHz frequency segments. The U-SIG field transmitted in each of the four 20 MHz frequency segments of an 80 MHz frequency segment MA / a / ZUZJ / UUUl ÓZ could be duplicated or could be different from each other. For example, the U-SIG11, U-SIG12, U-SIG13, and U-SIG14 fields transmitted in the 20 MHz frequency segments of the same 80 MHz frequency segments 128 could be duplicated or could be different from each other. According to various modalities, the term frequency segment could be used interchangeably with the term subchannel. The U-SIG field of an EHT TB PPDU consists of two long, co-coded orthogonal frequency-division multiplexing (OFDM) symbols. The U-SIG field is transmitted using 52 data tones and 4 pilot tones per 20 MHz and modulated in the same mode as the HE-SIG-A field of 802.11ax. Figure ID shows Table 130 of fields realized in a U-SIG field of an EHT TB PPDU. As shown in Table 130, a U-SIG field could comprise a 26-bit U-SIG1 and a 26-bit U-SIG2. The U-SIG1 field could comprise a PHY version identifier field (3 bits), an uplink / downlink flag or advisory (UL / DL) field (1 bit), a basic service placement (BSS) color field (6 bits), a transmit opportunity duration (TXOP) field (7 bits), a bandwidth (BW) field (3 bits), and a MA / a / ZUZJ / UUUT ÓZ requests simultaneous EHT TB PPDU transmissions from STA1 and STA2 with a bandwidth of 80 MHz. The basic EHT 202 trigger table indicates a combination of a large RU from RU2 of 484 tones and a RU1 of 242 tones distributed to STA1, and a large RU from RU2 of 242 tones distributed to STA2. In general, RUs with 242 tones or more could be defined as large RUs, while RUs with fewer than 242 tones could be defined as small RUs. The EHT 202 Basic Activator Box also indicates that the ED-based CCA needs to be performed by STA1 and STA2 during a Short Inter-Box Space (SIES) 204 immediately after receiving the EHT 202 Basic Activator Box.Based on the CCA results, it is determined that a 20 MHz subchannel overlapping with the distributed RU combination for STA1 is considered busy, while the 20 MHz subchannel overlapping with the distributed RU for STA2 is considered idle. Thus, only STA2 can transmit an EHT TB PPDU on the distributed RU, while STA1 cannot. As a result, the entire distributed RU or large RU combination to a STA could be wasted, even if only a small number of the 20 MHz subchannels overlapping with the distributed RU or large RU combination are considered busy, which would degrade the... MA / a / ZUZJ / UUUl ÓZ system performance. Therefore, this description proposes the following solution to the problem mentioned above. Each RU or RU combination larger than 242 tones is associated with two or more RUs or RU combinations. Each of the two or more RUs or RU combinations associated with a RU or RU combination larger than 242 tones is a large RU or RU combination, which will be permitted for the EHT WLAN. Each of the two or more RUs or RU combinations associated with a RU or RU combination larger than 242 tones has a size no larger than the RU or RU combination itself. To reduce the number of RUs or RU combinations associated with a RU or RU combination, some restrictions may be mandatory. For example, each of the RUs or RU combinations associated with a RU or RU combination no larger than 2*996 tones has a size of at least X% (e.g., X = 50) of the size of the RU or RU combination.In addition, each of the RU or RU combinations associated with a RU or RU combination larger than 2*996 tones has a size greater than X% (e.g., X = 50) of the size of the RU or RU combination. Example RUs or associated RU combinations with each RU or RU combination larger than 242 tones (where X = 50) according to various modalities are shown in Table 300 of Figure 3. For example, with reference to the 484-tone RU (RU484) which is applicable to a PPDU BW of 40 MHz, 80 MA / a / ZUZJ / UUUl ÓZ MHz, 160 / 80 + 80 MHz, and 320 / 160 + 160 MHz, the associated RUs or RU combinations are the RU484 and the 242-tone RU (RU242). For the RU242, there are two options: either a first RU242 or a second RU242 of the RU484. With reference to a combination of the RU242 and the RU484 (RU242+RU484), which is applicable to a PPDU BW of 80 MHz, 160 / 80+80 MHz, and 320 / 160+160 MHz, the associated RUs or RU combinations are the RU242+RU484 and the RU484 of the RU242+RU484. As can be seen in Table 300, the RU242+RU484 is permitted only within the same 80 MHz frequency segment, while the RU484+RU996 is permitted only within the same 160 MHz frequency segment. Figure 4 shows a format for an EHT 400 basic trigger box according to various modalities. The EHT 400 basic trigger box may comprise a common information field 402 and one or more user information fields 404. The trigger type field 406 in the common information field 402 indicates that the 400 box is an EHT basic trigger box. Each of one or more of the user information fields 404 may comprise a distribution field RU 418 indicating a distributed RU or RU combination to an STA indicated in an AID12 field 416. Each of one or more of the user information fields 404 may comprise a trigger-dependent user information field 408 that includes a disabled distribution field RU 410. The RU 410 Adaptation Off field indicates whether an RU adaptation procedure is disabled for the STA. When the RU 410 Adaptation Off field is set to 1, the RU adaptation procedure is disabled for the STA. When the RU 410 Adaptation Off field is set to 0, RU adaptation is enabled or permitted for the STA. Additionally, when the RU or RU combination distributed for the STA is no larger than 242 tones, the RU 410 Adaptation Off field must be set to 1. The common information field 402 could also comprise a required carrier detection (CS) field 412 indicating whether the ED base CCA is required by each scheduled STA prior to the EHT TB PPDU transmission. The common information field 402 could also comprise a UL 414 punch channel information field, which could comprise N subfields, each of which indicates uplink punch channel information within a corresponding 80 MHz frequency segment. For example, N=0 when UL BW = 20 or 40 MHz, N=1 when UL BW = 80 MHz, N=2 when UL BW = 160 / 80+80 MHz, and N=4 when UL BW = 320 / 160+160 MHz. Each of the N UL punch channel information subfields could be a 4-bit bitmap, where a bit set to 1 indicates that the corresponding 20 MHz subchannel is punched; and set to 0 otherwise. MA / a / ZUZJ / UUUl ÓZ According to several modalities, an STA could perform a RU adaptation procedure when the RU adaptation disabled field in the STA's user information field on a basic EHT activator request box is set to 0. The RU or RU combination distributed to the STA could be adapted to one of its associated RUs or RU combinations according to the results of the ED-based CCA performed by the STA. When part of the distributed RU or RU combination that is considered inactive matches one of its associated RUs or RU combinations, the distributed RU or RU combination is adapted to be one of its associated RUs or RU combinations.When a portion of a distributed RU or RU combination that is considered inactive does not coincide with any of its associated RUs or RU combinations, even though it covers at least one of its associated RUs or RU combinations, the distributed RU or RU combination is adapted to be one of its associated RUs or RU combinations that overlaps with the portion of the distributed RU or RU combination to the greatest extent. Furthermore, when a portion of a distributed RU or RU combination that is considered inactive does not coincide with or cover any of its associated RUs or RU combinations, the distributed RU or RU combination is not adapted to any of its associated RUs or RU combinations. Figure 5 shows an illustration 500 of how the RU adaptation is achieved through an STA in accordance with MA / a / ZUZJ / UUUl various modes. In this illustration, a combination of the 3rd RU484 and the 1st RU996 (RU484+RU996) 506, 512, 518 is distributed to the STA for EHT TB PPDU transmission with a BW of 160 MHz, comprising a first frequency segment of 80 MHz 502 and a second frequency segment of 80 MHz 504. In example A, a 20 MHz subchannel 508 that overlaps with the distributed RU combination 506 is considered to be occupied based on the ED-based CCA results performed by the STA. Therefore, the distributed RU combination 506 is adapted to one of its associated RU or RU combinations, i.e., the adapted RU 510 (the 1st RU996). In example B, a 20 MHz subchannel 514 that overlaps with the distributed RU combination 512 is considered to be occupied based on the ED-based CCA results performed by the STA.Therefore, the distributed RU combination 512 is matched to one of its associated RUs or RU combinations, namely, the matched RU combination 516 (the first RU242 and the second RU484). In Example C, the 20 MHz subchannels 520 and 522, which overlap with the distributed RU combination 518, are considered to be occupied based on the ED-based CCA results performed by the STA. In this case, part of the distributed RU combination 518, which is considered to be idle, does not overlap with or cover any of its associated RUs or RU combinations. Therefore, the distributed RU combination 518 is not matched to any of its associated RUs or RU combinations. According to the first modality, the STA behavior for implementing EHT TB PPDU transmission is as follows. When a RU adaptation procedure is not performed by an STA, an 802.11ax-type EHT TB PPDU transmission procedure is performed by the STA. When a RU adaptation procedure is performed by an STA and the RU or RU combination distributed to the STA is adapted to one of its associated RUs or RU combinations according to the results of the ED-based CCA performed by the STA, the STA prepares an EHT TB PPDU according to the adapted RU or RU combination, as well as the common transmission parameters and other user-specific transmission parameters (excluding the distributed RU or RU combination) indicated in the common information field and the user information field of the STA in an EHT basic activator request box.Furthermore, the drill channel information field of the U-SIG field in the EHT TB PPDU is set according to the UL drill channel information field of the common information field in the EHT basic trigger requester box. For example, the value of the drill channel information field of the U-SIG transmitted in an 80 MHz frequency segment is set to the value of the UL drill channel information subfield of the EHT basic trigger requester box that corresponds to the 80 MHz frequency segment. MA / a / ZUZJ / UUUl ÓZ MA / a / ZUZJ / UUUl On the other hand, when a RU adaptation procedure is performed by an STA and the RU or RU combination distributed to that STA is not adapted to any of its associated RUs or RU combinations according to the ED-based CCA results performed by the STA, the STA does not transmit an EHT TB PPDU. Advantageously, the transmission performance of the activator-based UL MU can be improved. An EHT TB PPDU transmission procedure performed by an STA upon receiving an EHT Basic Activator box requesting the STA to perform the ED Base CCA before the EHT TB PPDU transmission according to the first mode is illustrated in flowchart 600 of Figure 6. The process begins in step 602. In step 604, the ED Base CCA is performed by the STA without an AP. In step 606, it is determined whether the RU Adaptation Disabled field in the STA User Information field of the EHT Basic Activator box is set to 0, and the STA attempts to perform a RU Adaptation procedure. If it is determined that this is not the case, the process continues to step 616, where an 802.11ax-type EHT TB PPDU transmission procedure is performed, and then the process ends in step 614.On the other hand, if it is determined in step 606 that the RU adaptation disabled field in the STA user information field of the EHT basic trigger box is set to 0 and the STA attempts to perform an RU adaptation procedure, the process continues to step 608 where an RU adaptation procedure is performed according to the ED base CCA results. In step 610, it is determined whether a distributed RU or RU combination is adapted to one of its associated RUs or RU combinations. If it is determined that this is not the case, the process ends in step 614. Otherwise, the process continues to step 612 where an EHT TB PPDU is prepared according to the adapted RU or RU combination and is then transmitted. The process then ends in step 614. According to the first mode, the AP behavior for implementing EHT TB PPDU reception is as follows. When the distributed RU or RU combination for the STA is for a multi-user, multiple-output, multiple-input (MU-MIMO) distribution, the RU adaptation disabled field must also be set to 1. When receiving an EHT TB PPDU transmitted by an STA with RU adaptation disabled, the AP decodes the EHT TB PPDU according to the distributed RU or RU combination using an 802.11ax-type EHT TB PPDU reception procedure. When receiving an EHT TB PPDU transmitted by an STA with RU adaptation enabled, the AP decodes the EHT TB PPDU according to the following procedure: signal detection is performed using one or more of the pre-EHT modulated fields of the EHT TB PPDU (i.e., L-STF, L-LTF, the L field). ML / a / ZUZ J / UUU1ÓZ The SIG, RL-SIG, and U-SIG fields are transmitted on all 20 MHz subchannels corresponding to the RU or RU combination distributed to the STA. Based on the signal detection results, the STA can determine the appropriate RU or RU combination. The BSS color indicated in the U-SIG field can be used to exclude transmission of the Overlay Basic Service Set (OBSS) so that the appropriate RU or RU combination can be determined. The remaining EHT TB PPDU is then decoded by the AP according to the appropriate RU or RU combination. For example A, illustrated in Figure 5, where an RU combination of RU996 and RU484 is distributed to an STA, it is adapted to RU996.When an AP receives an EHT TB PPDU transmitted by the STA, the signal would be detected by the AP on all four 20 MHz subchannels that correspond to the Ira RU996 and in this way, the AP is able to determine that the adapted Ru is the lera RU996. An EHT TB PPDU reception procedure performed by an AP when a STA is required to perform the ED base CCA before transmitting EHT TB PPDU according to the first mode is illustrated in flowchart 700 of Figure 7. The process begins in step 702. In step 704, it is determined whether the RU adaptation disabled field in the STA user information field of the box MA / a / ZUZJ / UUUl ÓZ Basic EHT Activator Requester is set to 0. If it is determined that this is not the case, the process continues to step 716 where an 802.11ax type EHT TB PPDU receive procedure is performed, and then the process ends in step 714. On the other hand, if it is determined in step 704 that the RU Adaptation Disabled field in the STA User Information field of the Basic EHT Activator Requester box is set to 0, the process continues to step 706 where signal detection is performed using one or more of the pre-EHT modulated fields of the EHT TB PPDU transmitted on all 20 MHz subchannels corresponding to the distribution RU or RU combination. In step 708, it is determined whether a signal is detected on any of the 20 MHz subchannels corresponding to the distributed RU or RU combination. If it is determined that this is not the case, the process ends at stage 714.Otherwise, the process continues to step 710 where the RU or adapted RU combination is determined. In step 712, the remaining EHT TB PPDU is processed according to the RU or adapted RU combination. The process then ends in step 714. According to a second modality, the STA behavior for implementing EHT TB PPDU transmission is as follows. When a RU adaptation procedure is performed by an STA and the RU or RU combination distributed to the STA is adapted to one of its associated RUs or RU combinations MA / a / ZUZJ / UUUl in accordance with the results of the ED base CCA performed by the STA, the STA prepares an EHT TB PPDU in accordance with the adapted RU or RU combination, as well as the common transmission parameters and other user-specific transmission parameters (excluding the distributed RU or RU combination) indicated in the common information field and the user information field of the STA in the EHT basic activator request box. The process could then continue in one of two ways. In option A, the drill channel information field of the EHT TB PPDU U-SIG field is set according to the UL drill channel information field of the EHT Basic Activator Requester Box. For example, the value of the U-SIG drill channel information field transmitted on an 80 MHz frequency segment is set to the value of the UL drill channel information subfield of the EHT Basic Activator Requester Box corresponding to that 80 MHz frequency segment. The EHT TB PPDU U-SIG field contains an adapted RU distribution field that indicates the adapted RU or RU combination.In option B, the drill channel information fields of the EHT TB PPDU U-SIG fields are set in accordance with the UL drill channel information field of the EHT basic activator requester box and the RU or adapted RU combination. Figure 8 shows Table 800 of fields implemented in the U-SIG field of an EHT TB PPDU transmitted by an STA with the RU adaptation field disabled in the STA user information field of the EHT Basic Activator Request Box set to 0 under option A according to the second mode. As shown in Table 800, the U-SIG2 of the U-SIG field includes an adapted RU 802 distribution field. As explained previously, the adapted RU 802 distribution field indicates the adapted RU or RU combination. Figures 9A-9C show a table 900 illustrating how the RU or RU combination distributed larger than 242 tones and the adapted RU distribution field indicate an adapted RU or RU combination under option A according to the second modality. For example, in a case where the RU or RU combination distributed larger than 242 tones is RU484: - when the adapted distribution RU field indicates a value of 0, the adapted Ru is the distributed Ru (i.e., RU484); - when the adapted distribution field RU indicates a value of 1, the adapted Ru is the first RU242 within the distributed Ru; - when the adapted distribution field RU indicates a value of 2, the adapted Ru is the 2nd RU242 within the Ru MA / a / ZUZJ / UUUl ÓZ MA / a / ZUZJ / UUUl distributed; and - the values ​​3-15 are reserved. Furthermore, in a case where the distributed RU or RU combination larger than 242 tones is RU242+RU484: - when the adapted distribution field RU indicates a value of 0, the adapted Ru is the distributed Ru (i.e., RU242+RU484); - when the adapted distribution field RU indicates a value of 1, the adapted Ru is RU484 of the distributed Ru; and - Values ​​2-15 are reserved. Figure 10 shows a diagram 1000 illustrating how RU adaptation is achieved by STA1 and STA2 for the respective EHT TB PPDU transmissions with a bandwidth of 160 MHz comprising two 80 MHz frequency segments, 1002 and 1004, according to the second mode. An EHT basic trigger requester box for this example might have the following properties. Within the common information field of the EHT basic trigger box, the required CS field is set to 1 to indicate that ED base CCA is required, the UL BW field indicates UL BW = 160 / 80+80 MHz, and the two UL piercing channel information subfields are set to 0010 and 0000, respectively (see reference 1006). Namely, the 3rd 20 MHz subchannel within the 80 MHz frequency segment 1002 is pierced.Within the user information fields for STA1 and STA2 in the EHT basic activator box, the RU distribution fields indicate that a RU combination of the 1st RU4 84 and the 2nd RU996 is distributed to STA1 and the 4th RU242 is distributed to STA2. Additionally, the RU adaptation deactivation field is set to 0 for STA1 and is set to 1 for STA2. The RU matching according to the ED-based CCA results could be as follows. For STA1, the 2nd 20 MHz subchannel 1008 and the 5th 20 MHz subchannel 1010 are considered to be occupied, while the remaining 20 MHz subchannels that overlap with the 1st RU484 and the 2nd RU996 are considered inactive. The distributed RU combination for STA1 is matched to a RU combination of the 2nd RU242 1012 and the 2nd RU484 1014 within the 2nd RU996. For STA2, the 4th 20 MHz subchannel 1016 is considered inactive. Furthermore, within the EHT TB PPDU U-SIG that will be transmitted for STA1, the drill channel information field is set to 0000 (see reference 1018) and the adapted RU distribution field is set to 3 if under option A, or the drill channel information field is set to 1000 (see reference 1020) if under option B.For the EHT TB PPDU U-SIG to be transmitted for STA2, the drill channel information field is set to 0000 (see reference 1022). An EHT TB PPDU transmission procedure performed by an STA when receiving an EHT basic trigger box requesting the STA to perform the ED base CCA prior to the EHT TB PPDU transmission for the second mode is similar to the first mode (i.e., as shown in flowchart 600 of figure 6), except that the EHT TB PPDU U-SIG is set according to option A or option B. According to the second mode, when an AP receives an EHT TB PPDU transmitted by a STA with RU adaptation disabled, the AP decodes the EHT TB PPDU according to the distributed RU or RU combination using an 802.11ax-type EHT TB PPDU reception procedure. On the other hand, if the EHT TB PPDU is transmitted by a STA with RU adaptation enabled, the AP decodes the EHT TB PPDU according to the following procedure: • Determine the RU or adapted RU combination from the adapted RU distribution field or the drill channel information field in the EHT TB PPDU U-SIG field; and • Decode the remaining EHT TB PPDU according to the RU or adapted RU combination. Figure 11 shows a flowchart illustrating an EHT TB PPDU reception procedure performed by an AP when the STA is required to perform the ED base CCA before the EHT TB PPDU transmission in accordance with the MA / a / ZUZJ / UUUl ÓZ second mode. The process begins at step 1102. In step 1104, it is determined whether the RU adaptation disabled field in the EHT Basic Activator Box STA user information field is set to 0. If it is determined that this is not the case, the process continues to step 1112 where an 802.11ax type EHT TB PPDU reception procedure is performed, and the process then ends at step 1110. Otherwise, the process continues from step 1104 to step 1106 where the adapted RU or RU combination from the adapted RU distribution field or the U-SIG field drill channel information field is determined. In step 1108, the remaining EHT TB PPDU is processed according to the adapted RU or RU combination. The process then ends at step 1110. According to a third modality, the STA behavior for implementing EHT TB PPDU transmission is as follows. When an RU adaptation procedure is performed by an STA, an 802.11ax-type EHT TB PPDU transmission procedure is also performed by the STA. When an RU adaptation procedure is performed by an STA and the RU or RU combination distributed to the STA is adapted to one of its associated RUs or RU combinations according to the results of the ED-based CCA performed by the STA, the STA prepares an EHT TB PPDU according to the adapted RU or RU combination, the common transmission parameters (which include MA / a / ZUZJ / UUUl ÓZ (the additional packet padding time) and other user-specific transmission parameters (excluding the distributed RU or RU combination) are indicated in the Common Information field and the STA User Information field of the EHT Basic Activator Request Box. The EHT TB PPDU is prepared by the STA in a manner similar to 802.11ax, followed by additional packet padding so that the AP has sufficient time to perform blind decoding on the EHT TB PPDU. Furthermore, when an RU adaptation procedure is performed by an STA and the distributed RU or RU combination for that STA is not adapted to any of its associated RUs or RU combinations according to the results of the ED-based CCA performed by the STA, the STA does not transmit an EHT TB PPDU. An EHT TB PPDU transmission procedure performed by an STA upon receiving an EHT Basic Activator Box requesting the STA to perform the ED Base CCA prior to the EHT TB PPDU transmission according to the third mode is illustrated in flowchart 1200 of Figure 12. The process begins in step 1202. In step 1204, the ED Base CCA is performed by the STA. In step 1206, it is determined whether the RU Adaptation Disabled field in the STA User Information field of the EHT Basic Activator Box is set to 0. If it is determined that this is not the case, the process continues to step 1216 where an 802.11ax-type EHT TB PPDU transmission procedure is performed, and then the process ends in step 1214. On the other hand, if it is determined in step 1206 that the RU adaptation disabled field in the STA user information field of the EHT basic trigger box is set to 0, the process continues to step 1208 where an RU adaptation procedure is performed according to ED base CCA results. In step 1210, it is determined whether a distributed RU or RU combination is adapted to one of its associated RUs or RU combinations. If it is determined that this is not the case, the process ends in step 1214. Otherwise, the process continues to step 1212 where an EHT TB PPDU is prepared according to the adapted RU or RU combination and the additional packet padding duration and is then transmitted. The process then ends in step 1214. According to the third mode, the AP behavior for implementing the trigger-based UL MU transmission is as follows. When an EHT basic trigger frame is transmitted to request the EHT TB PPDU transmission, the common information field includes an additional packet padding duration field to indicate the additional packet padding duration on top of the normal packet padding. When an EHT TB PPDU transmitted by a STA with RU adaptation disabled is received, the AP decodes the EHT TB PPDU according to the distributed RU or RU combination. MA / a / ZUZJ / UUUl ÓZ using an 802.11ax type EHT TB PPDU reception procedure. On the other hand, when an EHT TB PPDU transmitted by a STA with the RU adaptation allowed is received, the AP decodes the EHT TB PPDU according to the following procedure: • determine the RUs or RU combinations associated with the distributed RU or RU combination, and • perform blind decoding of the EHT TB PPDU according to the associated RUs or RU combinations. Figure 13 shows a format of an EHT 1300 basic activator box according to the third modality. While similar to the EHT 400 basic activator box in Figure 4, the common information field of the EHT 1300 basic activator box includes a new additional duration for the 1302 packet filling field, which, as previously described, indicates the additional packet filling duration on top of the normal packet filling. Figure 14 shows a table 1400 illustrating the number of blind decodings required for each of the RUs or RU combinations larger than 242 tones according to the third modality. For example, with reference to RU484, the associated RUs or RU combinations are RU484 and RU242 (two options), and thus the number of blind decodings required is 3. With reference to the MA / a / ZUZJ / UUUl ÓZ RU242+RU484, the associated RU or RU combinations are RU242+RU484 and RU484, and thus the required blind decoding number is 2. Figure 15 shows a flowchart illustrating an EHT TB PPDU receive procedure performed by an AP when the STA is required to perform the ED base CCA before transmitting an EHT TB PPDU in accordance with the third mode. The process begins in step 1502. In step 1504, it is determined whether the RU adaptation disabled field in the STA user information field of the EHT base trigger box is set to 0. If it is determined that this is not the case, the process continues to step 1512 where an 802.11ax-type EHT TB PPDU receive procedure is performed, and the process then ends in step 1510. Otherwise, the process continues from step 1504 to step 1506 where the RU or RU combination associated with the distributed RU or RU combination is determined. In step 1508, blind decoding according to the RUs or associated RU combinations is performed. The process then ends in step 1510. Advantageously, unlike the first and second modes, in an activator-based UL MU transmission, the RU adaptation can be activated for a connected STA in a MU-MIMO transmission according to the third ML / a / ZUZJ / UUU IÓZ modality. Figure 16 shows a flowchart 1600 illustrating a communication method according to several modalities. In step 1602, an activator frame comprises a common information field and a plurality of user information fields, wherein each of the plurality of user information fields comprises a first field indicating whether a RU adaptation procedure is deactivated for a communication device directed by each of the plurality of user information fields, and a second field indicating a RU or RU combination distributed to the communication device. In step 1604, the generated activator frame is transmitted. Figure 17 shows a partially cutaway schematic view of a 1700 communication device that can be implemented for UL MU activator base transmission according to the first three modes. The 1700 communication device could be implemented as an STA or an AP according to various modes. Several functions and operations of the 1700 communication apparatus are layered according to a hierarchical model. In this model, lower layers report to and receive instructions from higher layers, in accordance with IEEE specifications. For simplicity, the details of the hierarchical model are not discussed in this description. MA / a / ZUZJ / UUUl ÓZ As shown in Figure 17, the communication apparatus 1700 could include the circuit assembly 1714, at least one radio transmitter 1702, at least one radio receiver 1704, and multiple antennas 1712 (for simplicity, only one antenna is shown in Figure 17 for illustrative purposes). The circuit assembly could include at least one controller 1706 for use in the software- and hardware-assisted execution of the tasks it is designed to perform, which includes controlling communications with one or more other communication apparatuses such as APs and STAs in a MIMO wireless network.At least controller 1706 could control at least one transmit signal generator 1708 to generate the frames to be sent via at least radio transmitter 1702 to one or more other STAs or APs, and at least one receive signal processor 1710 to process the frames received via at least radio receiver 1704 from one or more of the other STAs or APs. At least the transmit signal generator 1708 and at least the receive signal processor 1710 could be separate modules of the communication apparatus 1700 that communicate with at least controller 1706 for the functions mentioned above. Alternatively, at least the transmit signal generator 1708 and at least the receive signal processor 1710 could be included in at least controller 1706.It is worth noting for those skilled in the technology that the arrangement of these functional modules is flexible and can vary depending on practical needs and / or requirements. The processing, storage, and other relevant data control equipment can be provided on a suitable circuit board and / or in chip sets. In various configurations, when in operation, at least one radio transmitter 1702, at least one radio receiver 1704, and at least one antenna 1712 could be controlled by at least one controller 1706. Furthermore, while only one radio transmitter 1702 is shown, it will be appreciated that there may be more than one of these transmitters. In several configurations, when in operation, at least the 1704 radio receiver, together with at least the 1710 receive signal processor, forms a 1700 communication apparatus receiver. The 1700 communication apparatus receiver, when in operation, provides the functions required for UL MU trigger-based communication. While only one 1704 radio receiver is shown, it should be noted that more than one of these receivers may exist. The 1700 communication apparatus, when in operation, provides the functions required for activator-based UL MU transmission. For example, the 1714 circuit assembly could, in operation, generate a MA / a / ZUZJ / UUUl ÓZ activator frame comprising a common information field and a plurality of user information fields, wherein each of the plurality of user information fields comprises a first field indicating whether a RU adaptation procedure is deactivated for another communication device directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the other communication device. Transmitter 1702 could, in operation, transmit the generated activator frame. The RU adaptation procedure could be disabled for the other communication device when the distributed RU or RU combination is no larger than 242 tones. The common information field of the trigger box could include a field indicating the additional packet padding time. The distributed RU or RU combination could be associated with two or more RUs or RU combinations. Each of the two or more RUs or RU combinations associated with the distributed RU or RU combination could be no larger than the distributed RU or RU combination. Each of the two or more RUs or RU combinations associated with the distributed RU or RU combination could be a large-sized RU or RU combination permitted for the EHT WLAN. When the RU adaptation procedure is performed by the other communication device and part of the RU or ML / a / ZUZJ / UUU IÓZ distributed RU combination that is considered to be inactive matches one of the two or more RU or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination could fit one of the two or more RU or RU combinations associated with the distributed RU or RU combination. When the RU adaptation procedure is performed by the other communication apparatus and part of the RU or distributed RU combination that is considered to be inactive does not coincide with any of the two or more RUs or RU combinations associated with the distributed RU or RU combination, although it covers at least one of the two or more RUs or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination could be adapted to at least one of the two or more RUs or RU combinations associated with the distributed RU or RU combination that overlaps with the part of the distributed RU or RU combination to the greatest extent. When the RU adaptation procedure is performed by the other communication apparatus and part of the distributed RU or RU combination that is considered to be inactive does not match or cover any of the two or more RUs or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination could not adapt to some of the two or more RUs or RU combinations associated with the RU or MA / a / ZUZJ / UUUl ÓZ distributed RU combination. MA / a / ZUZJ / UUUl Receiver 1704 could, in operation, receive a trigger-based PPDU transmitted by the other communication apparatus. Circuit assembly 1714 could further be configured to perform signal detection using one or more fields of the trigger-based PPDU transmitted on all 20 MHz subchannels corresponding to the distributed RU or RU combination, and to determine a RU or RU combination that is adapted by the other communication apparatus from the distributed RU or RU combination according to the CCA results. A U-SIG field of the trigger-based PPDU could comprise a signaling field indicating a RU or RU combination that is adapted by the other communication apparatus from the distributed RU or RU combination according to the CCA results. The signaling field could further indicate the piercing channel information on an 80 MHz frequency segment on which the USIG field of the trigger-based PPDU is transmitted. The 1714 circuit set could also be configured to apply blind decoding to the trigger-base received PPDU according to the two or more RUs or RU combinations associated with the distributed RU or RU combination. As described above, the modalities in this description provide an advanced communication system, methods, and communication devices that enable the UL MU activator base transmission. The present description can be implemented using software, hardware, or software in cooperation with hardware. Each functional block used in the description of each mode, as previously described, can be implemented, partially or completely, by means of a Large Structured Instrument (LSI) such as an integrated circuit, and each process described in each mode could be controlled, partially or completely, by the same LSI or a combination of LSIs. The LSI could be implemented individually as chips, or a chip could be configured to include some or all of the functional blocks. The LSI could include data input and output coupled to it. Here, the LSI could be referred to as an IC, a system LSI, a super LSI, or an ultra LSI, depending on the degree of integration.However, the implementation technique for an integrated circuit is not limited to the LSI and could be carried out using a dedicated circuit, a general-purpose processor, or a special-purpose processor. Furthermore, a field-programmable gate array (FPGA) that can be programmed after the LSI is manufactured, or a reconfigurable processor in which the connections and settings of the circuit cells within the LSI can be reconfigured, could be used. This description can be implemented as either digital or analog processing. Future technology may also advance. MA / a / ZUZJ / UUUl ÓZ MA / a / ZUZJ / UUUl of integrated circuits replaces LSIs as a result of advances in semiconductor or other derivative technologies; the functional blocks could be integrated using future integrated circuit technology. Biotechnology may also be applied. This description can be made using any type of apparatus, device or system that has a communication function, which is referred to as a communication apparatus. The communication apparatus could comprise a transceiver and a set of processing / control circuitry. The transceiver could comprise and / or function as both a receiver and a transmitter. The transceiver, as a transmitter and receiver, could include an RF (radio frequency) module comprising amplifiers, RF modulators / demodulators, and the like, and one or more antennas. Some non-limiting examples of this communication apparatus include a telephone (e.g., a cell phone, a smartphone), a tablet-type personal computer (PC) (e.g., laptop, desktop, netbook computers), a camera (e.g., a digital still / video camera), a digital player (a digital audio / video player), a wearable device (e.g., a handheld camera, a smartwatch, a tracking device), a game console, a digital book reader, a remote health / remote medicine device (remote health and medicine), and a vehicle that provides communication functionality (e.g., car, airplane, vessel), and various combinations thereof. The communication apparatus is not limited to a portable or movable device, and could also include any type of apparatus, device or system that is not portable or fixed, such as a smart home device (e.g., appliance, lighting, smart meter, control panel), a vending machine and any other type of thing on an Internet of Things (IoT) network. Communication could include the exchange of data, for example, through a cellular system, a wireless system (LAN), a satellite system, etc., and various combinations thereof. The communication apparatus could comprise a device such as a controller or sensor coupled with a communication device that performs a communication function as described herein. For example, the communication apparatus could comprise a controller or sensor that generates control signals or data signals used by a communication device that performs a communication function of the communication apparatus. The communication apparatus could also include an infrastructure facility, such as a base station, an access point, and any other apparatus, device, or system that communicates with or controls apparatus such as those in the non-limiting examples above. It will be understood that while some properties of the different modalities have been described with reference to a communication apparatus, the corresponding properties also apply to the methods of various modalities, and vice versa. While example modalities have been presented in the preceding detailed description of these modalities, it should be noted that a large number of variations exist. Furthermore, it should be noted that the example modalities are examples and are not intended to limit the scope, applicability, operation, or configuration of this description in any way. Rather, the preceding detailed description will provide those skilled in the art with a convenient roadmap for implementing the example modalities. It is understood that various examples could be implemented in the function and arrangement of the stages and method of operation described in the example modalities and modules. ML / a'ZUZ J / UUU1 structures of the devices described in the example modalities without departing from the scope of the subject matter as indicated in the attached claims. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A communication apparatus, characterized in that it comprises: a set of circuits, which in operation, generates an actuator frame comprising a common information field and a plurality of user information fields; and a transmitter, which in operation, transmits the generated actuator frame; wherein each of the plurality of user information fields comprises a first field indicating whether a resource unit (RU) adaptation procedure is deactivated for another communication apparatus directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the other communication apparatus.

2. The communication apparatus according to claim 1, characterized in that the RU adaptation procedure is deactivated for the other communication apparatus when the distributed RU or RU combination has a size no larger than 242 tones.

3. The communication apparatus according to claim 1, characterized in that the common information field of the activator box comprises a field indicating the additional packet filling time.

4. The communication apparatus according to claim 1, characterized in that the distributed RU or RU combination is associated with two or more RUs or RU combinations.

5. The communication apparatus according to claim 1, characterized in that each of the two or more RUs or RU combinations associated with the distributed RU or RU combination has a size no larger than the distributed RU or RU combination.

6. The communication apparatus according to claim 1, characterized in that each of the two or more RUs or RU combinations associated with the distributed RU or RU combination is a large-sized RU or RU combination permitted for an extremely high-performance wireless local area network (EHT WLAN).

7. The communication apparatus according to claim 1, characterized in that when the RU adaptation procedure is performed by the other communication apparatus and part of the distributed RU or RU combination that is considered to be inactive coincides with one of the two or more RUs or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination is adapted to one of the two or more RUs or RU combinations associated with the MA / a / ZUZJ / UUUl ÓZ RU or distributed RU combination.

8. The communication apparatus according to claim 1, characterized in that when the RU adaptation procedure is performed by the other communication apparatus and part of the distributed RU or RU combination that is considered to be inactive does not coincide with any of the two or more RUs or RU combinations associated with the distributed RU or RU combination, although it covers at least one of the two or more RUs or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination is adapted to at least one of the two or more RUs or RU combinations associated with the distributed RU or RU combination that overlaps with the part of the distributed RU or RU combination to the greatest extent.

9. The communication apparatus according to claim 1, characterized in that when the RU adaptation procedure is performed by the other communication apparatus and part of the distributed RU or RU combination that is considered to be inactive does not coincide with or cover any of the two or more RUs or RU combinations associated with the distributed RU or RU combination, the distributed RU or RU combination is not adapted to any of the two or more RUs or RU combinations associated with the distributed RU or RU combination.

10. The communication apparatus according to claim 1, characterized in that it further comprises a MA / a / ZUZJ / UUUl ÓZ receiver, which, in operation, receives a trigger base physical layer protocol data unit (PPDU) transmitted by the other communication apparatus.

11. The communication apparatus according to claim 10, characterized in that the circuit assembly is further configured to: perform signal detection using one or more fields of the trigger base PPDU transmitted on all 20 MHz subchannels corresponding to the distributed RU or RU combination, and determine a RU or RU combination that is adapted by the other communication apparatus from the distributed RU or RU combination according to the results of the channel clearance assessment (CCA).

12. The communication apparatus according to claim 10, characterized in that a universal signal field (U-SIG) of the activator base PPDU comprises a signaling field indicating a RU or RU combination that is adapted by the other communication apparatus from the RU or RU combination distributed according to the CCA results.

13. The communication apparatus according to claim 12, characterized in that the signaling field further indicates the drilling channel information in an 80 MHz frequency segment in which the U-SIG field of the activator base PPDU is transmitted. MA / a / ZUZJ / UUUl ÓZ 14. The communication apparatus according to claim 10, characterized in that the circuit assembly is further configured to apply blind decoding to the PPDU received from the activator base according to the two or more RUs or RU combinations associated with the distributed RU or RU combination.

15. A communication method, characterized in that it comprises: generating an activator frame comprising a common information field and a plurality of user information fields; and transmitting the generated activator frame; wherein each of the plurality of user information fields comprises a first field indicating whether a RU adaptation procedure is deactivated for a communication apparatus directed by each of the plurality of user information fields and a second field indicating a RU or RU combination distributed to the communication apparatus.

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