Patent Description:
In the standardization of next generation wireless local area network (WLAN), a new radio access technology having backward compatibilities with IEEE <NUM>. 11a/b/g/n/ac/ax technologies has been discussed in the IEEE <NUM> Working Group and is named IEEE <NUM>. 11be Extremely High Throughput (EHT) WLAN.

11be EHT WLAN, in order to provide significant peak throughput and capacity increase beyond <NUM>. 11ax high efficiency (HE) WLAN, it is desired to increase the maximum channel bandwidth from <NUM> to <NUM>, increase the maximum number of spatial streams from <NUM> to <NUM> and to support multi-link operation. Further, in order to improve spectral efficiency over 11ax HE WLAN, it has been proposed to allow preamble puncturing for a physical layer protocol data unit (PPDU) transmitted to a single communication apparatus or multiple communication apparatuses.

However, there has been no much discussion on communication apparatuses and methods for control signaling, specifically on efficient signaling support for preamble puncturing for a PPDU transmitted to a single communication apparatus or multiple communication apparatuses in the context of EHT WLAN.

There is thus a need for communication apparatuses and methods that provide feasible technical solutions for control signaling in the context of EHT WLAN. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.

<CIT> relates to Null Data Packet Sounding for preamble punctured Physical Layer Convergence Procedure Protocol Data Unit (PPDU) for efficient use of a wireless channel bandwidth where a primary service co-exists. <NPL>, is a document covering the U-SIG content and a PPDU format design for EHT, and, among others, proposing compressed modes for MU PPDU and specific fields in the U-SIG and part of the common field in the EGT-SIG.

<CIT> provides techniques for preamble puncturing in wireless local area networks (WLANs). In one implementation, an AP can identify a single user (SU) preamble puncture transmission, and can signal in a common portion of a SIG-B field of a multi-user (MU) PPDU format that a resource unit (RU) size is assigned to a same user to indicate the SU preamble puncture transmission.

<NPL>, discusses EHT-SIG content channel options for supporting of flexible preamble puncturing and reduction of signaling overhead. Among others, this document teaches to indicate preamble puncturing by using the BW field in the U-SIG and patern information in the EHT-SIG.

The present application provides communication apparatuses and communication methods for control signaling in context of EHT WLAN.

The scope of the present invention is defined and limtied by the appended claims. Examples, aspects and embodiments not necessarily falling under the scope of the claims are provided in the application to better understand the invention.

Aspects of the disclosure will be better understood and readily apparent to one of ordinary skilled in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:.

Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale. For example, the dimensions of some of the elements in the illustrations, block diagrams or flowcharts may be exaggerated in respect to other elements to help an accurate understanding of the present aspects.

Some aspects of the present disclosure will be described, by way of example only, with reference to the drawings. Like reference numerals and characters in the drawings refer to like elements or equivalents.

In the following paragraphs, certain exemplifying aspects are explained with reference to an access point (AP) and a station (STA) for uplink or downlink control signaling, especially in a multiple-input multiple-output (MIMO) wireless network.

In the context of IEEE <NUM> (Wi-Fi) technologies, a station, which is interchangeably referred to as a STA, is a communication apparatus that has the capability to use the <NUM> protocol. Based on the IEEE <NUM>-<NUM> definition, a STA can be any device that contains an IEEE <NUM>-conformant media access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).

For example, a STA may be a laptop, a desktop personal computer (PC), a personal digital assistant (PDA), an access point or a Wi-Fi phone in a wireless local area network (WLAN) environment. The STA may be fixed or mobile. In the WLAN environment, the terms "STA", "wireless client", "user", "user device", and "node" are often used interchangeably.

Likewise, an AP, which may be interchangeably referred to as a wireless access point (WAP) in the context of IEEE <NUM> (Wi-Fi) technologies, is a communication apparatus that allows STAs in a WLAN to connect to a wired network. The AP usually connects to a router (via a wired network) as a standalone device, but it can also be integrated with or employed in the router.

As mentioned above, a STA in a WLAN may work as an AP at a different occasion, and vice versa. This is because communication apparatuses in the context of IEEE <NUM> (Wi-Fi) technologies may include both STA hardware components and AP hardware components. In this manner, the communication apparatuses may switch between a STA mode and an AP mode, based on actual WLAN conditions and/or requirements.

In a MIMO wireless network, "multiple" refers to multiple antennas used simultaneously for transmission and multiple antennas used simultaneously for reception, over a radio channel. In this regard, "multiple-input" refers to multiple transmitter antennas, which input a radio signal into the channel, and "multiple-output" refers to multiple receiver antennas, which receive the radio signal from the channel and into the receiver. For example, in an N × M MIMO network system, N is the number of transmitter antennas, M is the number of receiver antennas, and N may or may not be equal to M. For the sake of simplicity, the respective numbers of transmitter antennas and receiver antennas are not discussed further in the present disclosure.

In a MIMO wireless network, single-user (SU) communications and multi-user (MU) communications can be deployed for communications between communication apparatuses such as APs and STAs. MIMO wireless network has benefits like spatial multiplexing and spatial diversity, which enable higher data rates and robustness through the use of multiple spatial streams. According to various aspects, the term "spatial stream" may be used interchangeably with the term "space-time stream" (or STS).

<FIG> depicts a schematic diagram of SU communication <NUM> between an AP <NUM> and a STA <NUM> in a MIMO wireless network. As shown, the MIMO wireless network may include one or more STAs (e.g. STA <NUM>, STA <NUM>, etc.). If the SU communication <NUM> in a channel is carried out over whole channel bandwidth, it is called full bandwidth SU communication. If the SU communication <NUM> in a channel is carried out over a part of the channel bandwidth (e.g. one or more <NUM> subchannels within the channel is punctured), it is called punctured SU communication. In the SU communication <NUM>, the AP <NUM> transmits multiple space-time streams using multiple antennas (e.g. four antennas as shown in <FIG>) with all the space-time streams directed to a single communication apparatus, i.e. the STA <NUM>. For the sake of simplicity, the multiple space-time streams directed to the STA <NUM> are illustrated as a grouped data transmission arrow <NUM> directed to the STA <NUM>.

The SU communication <NUM> can be configured for bi-directional transmissions. As shown in <FIG>, in the SU communication <NUM>, the STA <NUM> may transmit multiple space-time streams using multiple antennas (e.g. two antennas as shown in <FIG>) with all the space-time streams directed to the AP <NUM>. For the sake of simplicity, the multiple space-time streams directed to the AP <NUM> are illustrated as a grouped data transmission arrow <NUM> directed to the AP <NUM>.

As such, the SU communication <NUM> depicted in <FIG> enables both uplink and downlink SU transmissions in a MIMO wireless network.

<FIG> depicts a schematic diagram of downlink MU communication <NUM> between an AP <NUM> and multiple STAs <NUM>, <NUM>, <NUM> in a MIMO wireless network. The MIMO wireless network may include one or more STAs (e.g. STA <NUM>, STA <NUM>, STA <NUM>, etc.). The MU communication <NUM> can be an OFDMA (orthogonal frequency division multiple access) communications or a MU-MIMO communication. For an OFDMA communication in a channel, the AP <NUM> transmits multiple streams simultaneously to the STAs <NUM>, <NUM>, <NUM> in the network at different resource units (RUs) within the channel bandwidth. For a MU-MIMO communication in a channel, the AP <NUM> transmits multiple streams simultaneously to the STAs <NUM>, <NUM>, <NUM> at same RU(s) within the channel bandwidth using multiple antennas via spatial mapping or precoding techniques. If the RU(s) at which the OFDMA or MU-MIMO communication occurs occupy whole channel bandwidth, the OFDMA or MU-MIMO communications is called full bandwidth OFDMA or MU-MIMO communications. If the RU(s) at which the OFDMA or MU-MIMO communication occurs occupy a part of channel bandwidth (e.g. one or more <NUM> subchannel within the channel is punctured), the OFDMA or MU-MIMO communication is called punctured OFDMA or MU-MIMO communications. For example, two space-time streams may be directed to the STA <NUM>, another space-time stream may be directed to the STA <NUM>, and yet another space-time stream may be directed to the STA <NUM>. For the sake of simplicity, the two space-time streams directed to the STA <NUM> are illustrated as a grouped data transmission arrow <NUM>, the space-time stream directed to the STA <NUM> is illustrated as a data transmission arrow <NUM>, and the space-time stream directed to the STA <NUM> is illustrated as a data transmission arrow <NUM>.

To enable uplink MU transmissions, trigger-based communication is provided to the MIMO wireless network. In this regard, <FIG> depicts a schematic diagram of trigger-based uplink MU communication <NUM> between an AP <NUM> and multiple STAs <NUM>, <NUM>, <NUM> in a MIMO wireless network.

Since there are multiple STAs <NUM>, <NUM>, <NUM> participating in the trigger-based uplink MU communication, the AP <NUM> needs to coordinate simultaneous transmissions of multiple STAs <NUM>, <NUM>, <NUM>.

To do so, as shown in <FIG>, the AP <NUM> transmits triggering frames <NUM>, <NUM>, <NUM> simultaneously to STAs <NUM>, <NUM>, <NUM> to indicate user-specific resource allocation information (e.g. the number of space-time streams, a starting STS number and the allocated RUs) each STA can use. In response to the triggering frames, STAs <NUM>, <NUM>, <NUM> may then transmit their respective space-time streams simultaneously to the AP <NUM> according to the user-specific resource allocation information indicated in the triggering frames <NUM>, <NUM>, <NUM>. For example, two space-time streams may be directed to the AP <NUM> from STA <NUM>, another space-time stream may be directed to the AP <NUM> from STA <NUM>, and yet another space-time stream may be directed to the AP <NUM> from STA <NUM>. For the sake of simplicity, the two space-time streams directed to the AP <NUM> from STA <NUM> are illustrated as a grouped data transmission arrow <NUM>, the space-time stream directed to the AP <NUM> from STA <NUM> is illustrated as a data transmission arrow <NUM>, and the space-time stream directed to the AP <NUM> from STA <NUM> is illustrated as a data transmission arrow <NUM>.

Trigger-based communication is also provided to the MIMO wireless network to enable downlink multi-AP communication. In this regard, <FIG> depicts a schematic diagram of downlink multi-AP communication <NUM>, between a STA <NUM> and multiple APs <NUM>, <NUM> in a MIMO wireless network.

Since there are multiple APs <NUM>, <NUM> participating in the trigger-based downlink multi-AP MIMO communication, the master AP <NUM> needs to coordinate simultaneous transmissions of multiple APs <NUM>, <NUM>.

To do so, as shown in <FIG>, the master AP <NUM> transmits triggering frames <NUM>, <NUM> simultaneously to the AP <NUM> and the STA <NUM> to indicate AP-specific resource allocation information (e.g. the number of space-time streams, a starting STS stream number and the allocated RUs) each AP can use. In response to the triggering frames, the multiple APs <NUM>, <NUM> may then transmit respective space-time streams to the STA <NUM> according to the AP-specific resource allocation information indicated in the triggering frame <NUM>; and the STA <NUM> may then receive all the space-time streams according to the AP-specific resource allocation information indicated in the triggering frame <NUM>. For example, two space-time streams may be directed to the STA <NUM> from AP <NUM>, and another two space-time streams may be directed to the STA <NUM> from AP <NUM>. For the sake of simplicity, the two space-time streams directed to the STA <NUM> from AP <NUM> are illustrated as a grouped data transmission arrow <NUM>, and the two space-time streams directed to the STA <NUM> from the AP <NUM> is illustrated as a grouped data transmission arrow <NUM>.

Due to packet/PPDU (physical layer protocol data unit) based transmission and distributed MAC (medium access control) scheme in <NUM> WLAN, time scheduling (e.g. TDMA (time division multiple access)-like periodic time slot assignment for data transmission) does not exist in <NUM> WLAN. Frequency and spatial resource scheduling is performed on a packet basis. In other words, resource allocation information is on a PPDU basis.

<FIG> depicts an example format of a PPDU <NUM> used for SU communications between an AP and a STA in a HE WLAN. Such a PPDU <NUM> is referred to as an HE SU PPDU <NUM>. The HE SU PPDU <NUM> may include a non-High Throughput Short Training Field (L-STF), a non-High Throughput Long Training Field (L-LTF), a non-High Throughput SIGNAL (L-SIG) field, a Repeated L-SIG (RL-SIG) field, a HE SIGNAL A (HE-SIG-A) field <NUM>, a HE Short Training Field (HE-STF), a HE Long Training Field (HE-LTF), a Data field and a Packet Extension (PE) field. The RL-SIG field is mainly used for identifying the format of an HE PPDU. The HE-SIG-A field <NUM> contains the necessary control information for decoding the Data field, such as uplink/downlink, modulation and coding scheme (MCS) and bandwidth (BW).

<FIG> shows an example format of a PPDU <NUM> used for downlink MU communications between an AP and multiple STAs in a HE WLAN, e.g. OFDMA transmission and full bandwidth MU-MIMO transmission. Such a PPDU <NUM> is referred to as an HE MU PPDU <NUM>. A HE MU PPDU may have a similar format as HE SU PPDU but include a HE SIGNAL B (HE-SIG-B) field <NUM>. In particular, the HE MU PPDU <NUM> may include a L-STF, L-LTF, L-SIG, R-SIG, HE-SIG-A field <NUM>, HE-SIG-B field <NUM>, a HE-STF, a HE-LTF, a Data field <NUM> and a PE field. In the HE MU PPDU <NUM>, the HE-SIG-B field <NUM> provides the OFDMA and MU-MIMO resource allocation information to allow STAs to look up the corresponding resources to be used in the Data field <NUM>, like indicated by an arrow <NUM>. The HE-SIG-A field <NUM> contains the necessary information for decoding the HE-SIG-B field <NUM>, e.g. MCS for HE-SIG-B, number of HE-SIG-B symbols, like indicated by an arrow <NUM>.

<FIG> depicts the HE-SIG-B field <NUM> in more detail. The HE-SIG-B field <NUM> includes (or consists of) a Common field <NUM>, if present, followed by a User Specific field <NUM> which together are referred to as the HE-SIG-B content channel. The HE-SIG-B field <NUM> contains a RU Allocation subfield which indicates the RU information for each of the allocations. The RU information includes a RU position in the frequency domain, an indication of the RU allocated for a non-MU-MIMO or MU-MIMO allocation, and the number of users in the MU-MIMO allocation. The Common field <NUM> is not present in the case of a full bandwidth MU-MIMO transmission. In this case, the RU information (e.g. the number of users in the MU-MIMO allocation) is indicated in the HE-SIG-A field <NUM>.

The User Specific field <NUM> includes (or consists of) one or more User field(s) for non-MU-MIMO allocation(s) and/or MU-MIMO allocation(s). A User field contains user information indicating a user-specific allocation (i.e. user-specific allocation information). In the example shown in <FIG>, the User Specific field <NUM> includes five user fields (User field <NUM>,. , User field <NUM>), wherein user-specific allocation information for an allocation (Allocation <NUM>) is provided by User field <NUM>, user-specific allocation information for a further allocation (Allocation <NUM> with <NUM> MU-MIMO users) is provided by User field <NUM>, User field <NUM>, and User field <NUM>, and user-specific allocation information for yet a further allocation (Allocation <NUM>) is provided by User field <NUM>.

<FIG> shows a format of a PPDU <NUM> used for uplink MU communications between an AP and multiple STAs in a HE WLAN. Such a PPDU <NUM> is referred to as an HE TB (trigger-based) PPDU <NUM>. A HE TB PPDU may have a similar format as HE SU PPDU. In particular, the HE TB PPDU <NUM> may include a L-STF, a L-LTF, a L-SIG field, a RL-SIG field, a HE-SIG-A field <NUM>, a HE-STF, a HE-LTF, a Data field and a PE field. The HE-STF of HE TB PPDU <NUM> has a duration of <NUM>. The HE TB PPDU <NUM> is used for uplink MU transmission that is in response to a triggering frame. Instead of using the HE-SIG-B field, the information required for the uplink MU transmission from one or more STAs is carried by the triggering frame that solicits this transmission. In a typical transmission of the HE TB PPDU <NUM>, HE-SIG-A related information is copied from the soliciting triggering frame into the HE-SIG-A field <NUM> of the HE TB PPDU <NUM>.

In 11ax HE WLAN, only preamble puncturing for a PPDU transmitted to multiple STAs is allowed. With the increase in the maximum channel bandwidth from <NUM> to <NUM>, it is an object of present disclosure to substantially overcome the existing challenges to provide communication apparatuses and methods for control signaling that allow preamble puncturing for a PPDU transmitted to a single STA or multiple STAs in order to improve spectral efficiency of EHT WLAN over 11ax HE WLAN. In particular, preamble puncturing for a PPDU used for SU, MU-MIMO or OFDMA transmission is provided in the present disclosure. According to various aspects, the term "preamble puncturing" may be used interchangeably with the term "channel puncturing".

According to various aspects, EHT WLAN supports non-trigger-based communications as illustrated in <FIG> and <FIG> and trigger-based communications as illustrated in <FIG> and <FIG>. In non-trigger-based communications, a communication apparatus transmits a PPDU to one other communication apparatus or more than one other communication apparatuses in an unsolicited manner. In trigger-based communications, a communication apparatus transmits a PPDU to one other communication apparatus or more than one other communication apparatuses only after a soliciting triggering frame is received.

<FIG> shows a schematic, partially sectioned view of a communication apparatus <NUM> according to the present disclosure. The communication apparatus <NUM> may be implemented as an AP or an STA.

As shown in <FIG>, the communication apparatus <NUM> may include circuitry <NUM>, at least one radio transmitter <NUM>, at least one radio receiver <NUM>, and at least one antenna <NUM> (for the sake of simplicity, only one antenna is depicted in <FIG> for illustration purposes). The circuitry <NUM> may include at least one controller <NUM> for use in software and hardware aided execution of tasks that the at least one controller <NUM> is designed to perform, including control of communications with one or more other communication apparatuses in a MIMO wireless network. The circuitry <NUM> may furthermore include at least one transmission signal generator <NUM> and at least one receive signal processor <NUM>. The at least one controller <NUM> may control the at least one transmission signal generator <NUM> for generating PPDUs (for example PPDUs used for non-trigger-based communications or PPDUs used for trigger-based multi-AP joint transmission if the communication apparatus <NUM> is an AP, and for example PPDUs used for non-trigger-based communications or PPDUs used for trigger-based uplink transmissions if the communication apparatus <NUM> is a STA) to be sent through the at least one radio transmitter <NUM> to one or more other communication apparatuses and the at least one receive signal processor <NUM> for processing PPDUs (for example PPDUs used for non-trigger-based communications or PPDUs used for trigger-based uplink transmissions if the communication apparatus <NUM> is an AP, and for example PPDUs used for non-trigger-based communications or PPDUs used for trigger-based multi-AP joint transmission if the communication apparatus <NUM> is a STA) received through the at least one radio receiver <NUM> from the one or more other communication apparatuses under the control of the at least one controller <NUM>. The at least one transmission signal generator <NUM> and the at least one receive signal processor <NUM> may be stand-alone modules of the communication apparatus <NUM> that communicate with the at least one controller <NUM> for the above-mentioned functions, as shown in <FIG>. Alternatively, the at least one transmission signal generator <NUM> and the at least one receive signal processor <NUM> may be included in the at least one controller <NUM>. It is appreciable to those skilled in the art that the arrangement of these functional modules is flexible and may vary depending on the practical needs and/or requirements. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. In various aspects, when in operation, the at least one radio transmitter <NUM>, at least one radio receiver <NUM>, and at least one antenna <NUM> may be controlled by the at least one controller <NUM>.

The communication apparatus <NUM>, when in operation, provides functions required for control signaling in non-trigger-based communications and trigger-based communications. For example, the communication apparatus <NUM> may be an AP, and the circuitry <NUM> (for example the at least one transmission signal generator <NUM> of the circuitry <NUM>) may, in operation, generate a transmission signal (for example a PPDU used for non-trigger-based communications or a PPDU used for trigger-based multi-AP joint transmission) comprising a first signal field and a second signal field, wherein the first signal field comprises punctured channel information and the second signal field comprises supplemental punctured channel information, wherein when the transmission signal is used for punctured SU or MU-MIMO transmission and the punctured channel information is able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field does not comprise the supplemental punctured channel information. The radio transmitter <NUM> may in operation, transmit the generated transmission signal to one or more other communication apparatuses.

The communication apparatus <NUM> may be a STA, and the radio receiver <NUM> may, in operation, receive a transmission signal (for example an PPDU used for non-trigger-based communications or a PPDU used for trigger-based multi-AP joint transmission) comprising a first signal field and a second signal field, wherein the first signal field comprises punctured channel information and the second signal field comprises supplemental punctured channel information, wherein when the transmission signal is used for punctured SU or MU-MIMO transmission and the punctured channel information is able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field does not comprise the supplemental punctured channel information. The circuitry <NUM> (for example the at least one receive signal processor <NUM> of the circuitry <NUM>) may, in operation, process the received transmission signal.

<FIG> shows a flow diagram <NUM> illustrating a communication method for transmitting generated transmission signal according to the present disclosure. In step <NUM>, a transmission signal is generated, the transmission signal (for example a PPDU used for non-trigger-based communications or a PPDU used for trigger-based multi-AP joint transmission) comprising a first signal field and a second signal field, wherein the first signal field comprises punctured channel information and the second signal field comprises supplemental punctured channel information, wherein when the transmission signal is used for punctured SU or MU-MIMO transmission and the punctured channel information is able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field does not comprise the supplemental punctured channel information. In step <NUM>, the generated transmission signal is transmitted to one or more other communication apparatuses.

In various aspects, wherein when the transmission signal is used for punctured SU or MU-MIMO transmission and the punctured channel information is not able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field comprises the supplemental punctured channel information that, together with the punctured channel information, indicates a channel puncturing pattern that is applied to the transmission signal. According to an aspect of present disclosure, wherein when the transmission signal is used for punctured OFDMA transmission and the punctured channel information is not able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field comprises the supplemental punctured channel information that, together with the punctured channel information, indicates the channel puncturing pattern that is applied to the transmission signal. In an aspect, the punctured channel information is able to indicate all channel puncturing patterns that are allowed for up to a determined bandwidth (e.g. <NUM>). In another aspect, the punctured channel information is able to indicate all channel puncturing patterns that are allowed for up to a determined bandwidth (e.g. <NUM>) and a part of channel puncturing patterns for bandwidths which are larger than the determined bandwidth. This may allow preamble puncturing for a PPDU transmitted to a single communication apparatus or multiple communication apparatuses and may advantageously enable efficient signaling support and improve spectral efficiency of 11be EHT WLAN over 11ax HE WLAN.

In the following paragraphs, certain exemplifying aspects are explained with reference to an AP and multiple STAs for control signaling to enable preamble puncturing for a PPDU transmitted to a single communication apparatus or multiple communication apparatuses in non-trigger-based communications.

<FIG> depicts a flow chart <NUM> illustrating a downlink communication according to the present disclosure, where the downlink communication is between an AP <NUM> and a single STA <NUM> or between an AP <NUM> and multiple communication apparatuses like STAs <NUM>, <NUM>. Contention based channel access procedures, e.g. enhanced distributed channel access (EDCA) procedures, is illustrated by block <NUM>, and short interframe spacing (SIFS) <NUM> is illustrated. The AP <NUM> may generate a transmission signal (for example an EHT basic PPDU) <NUM> comprising a first signal field and a second signal field, wherein the first signal field comprises punctured channel information and the second signal field comprises supplemental punctured channel information, wherein when the transmission signal is used for punctured SU or MU-MIMO transmission and the punctured channel information is able to indicate a channel puncturing pattern that is applied to the transmission signal, the second signal field does not comprise the supplemental punctured channel information. The ratio transmitter of AP <NUM> may transmit the generated transmission signal <NUM> to STA <NUM> or STAs <NUM>, <NUM>.

In IEEE <NUM> networks, a SIFS is the time spacing prior to transmission of an acknowledgement by a STA. After the last symbol of the transmission signal <NUM> is transmitted, a SIFS <NUM> may take effect, and at <NUM>, the radio transmitters of STAs <NUM>, <NUM> may simultaneously transmit their respective block acknowledgement (BA) frames <NUM>, <NUM> when the transmission signal <NUM> is transmitted to STAs <NUM>, <NUM>; or the radio transmitter of STA <NUM> may transmit its own BA frame <NUM> when the transmission signal <NUM> is transmitted to STA <NUM>.

According to the present disclosure, an EHT basic PPDU can be used for non-trigger-based SU or MU communications. <FIG> depicts an example format of an EHT basic PPDU <NUM>. The EHT basic PDDU <NUM> comprises a L-STF, L-LTF, L-SIG field, RL-SIG field, a universal signal (U-SIG) field <NUM>, an EHT signal (EHT-SIG) field <NUM>, an EHT-STF, an EHT-LTF, a Data field and a PE field. The L-STF, the L-LTF, the L-SIG field, the RL-SIG field, the U-SIG field and the EHT-SIG field may be grouped as pre-EHT modulated fields, while the EHT-STF, the EHT-LTF, the Data field and the PE field may be grouped as EHT modulated fields. Both U-SIG field <NUM> and EHT-SIG field <NUM> are present in the EHT basic PPDU transmitted to a single STA or multiple STAs.

According to various aspects, U-SIG field <NUM> has a duration of two orthogonal frequency-division multiplexing (OFDM) symbols. Data bits in the U-SIG field <NUM> are jointly encoded and modulated in the same manner as the HE-SIG-A field of <NUM>. Modulated data bits in the U-SIG field <NUM> are mapped to <NUM> data tones of each of the two OFDM symbols and duplicated for each <NUM> frequency segment in the same manner as the HE-SIG-A field of <NUM>. An example of transmission of U-SIG field <NUM>, where the bandwidth of EHT basic PPDU <NUM> is <NUM>, is illustrated in <FIG>. According to various aspects, the term "frequency segment" may be used interchangeably with the term "subchannel".

In various aspects, U-SIG field <NUM> has a same format regardless of whether EHT basic PPDU <NUM> is transmitted to a single STA or multiple STAs. U-SIG field <NUM> comprises two parts: U-SIG1 and U-SIG2, each comprising <NUM> data bits. U-SIG field <NUM> comprises all version independent bits and a part of version dependent bits. All version independent bits are included in U-SIG1 and have static location and bit definition across different physical layer (PHY) versions, the version independent bits comprising PHY version identifier (<NUM> bits), uplink/downlink (UL/DL) flag (<NUM> bit), basic service set (BSS) color (e.g. <NUM> bits), transmission opportunity (TXOP) duration (e.g. <NUM> bits), and bandwidth (e.g. <NUM> or <NUM> bits). The PHY version identifier of the version independent bits is used to identify the exact PHY version starting with <NUM>. The effect of including all version independent bits into one part of U-SIG field <NUM>, i.e. U-SIG1, is that the legacy STAs only require to parse U-SIG1 and thus their power efficiency can be improved. On the other hand, version dependent bits may have variable bit definition in each PHY version. The part of version dependent bits included in U-SIG field <NUM> may comprise PPDU type as well as EHT-SIG related bits which are used for interpreting EHT-SIG field <NUM>, and spatial reuse related bits which are used for coexisting with unintended STAs.

Table <NUM> illustrates an example format of U-SIG field <NUM>. As mentioned above, the U-SIG field <NUM> comprises two parts: U-SIG1 and U-SIG2, each of the two parts containing <NUM> data bits. U-SIG1 comprises a PHY Version Identifier field, an UL/DL Flag field, a BSS Color field, a TXOP Duration field, a BW (bandwidth) field, and a PPDU Type field; whereas U-SIG2 comprises an EHT-SIG Compression field, an EHT-SIG Dual sub-Carrier Modulation (DCM) field, an EHT-SIG EHT MCS field, a Number Of EHT-SIG Symbols Or Non-OFDMA Users field, and a Spatial Reuse field, followed by reserved bits, a Cyclic Redundancy Check (CRC) field for detecting error and tail bits. In an aspect, when the PHY Version Identifier field refers to <NUM>. 11be, the PPDU Type field may be set to "<NUM>" for EHT basic PPDU and "<NUM>" for EHT TB PPDU. Unless specified otherwise in this specification, it should be appreciable and apparent to one of ordinary skilled in the art that the standard definitions, protocols and functions of most of the fields in U-SIG field <NUM> listed in table <NUM> can be obtained from the <NUM>. 11ax specification.

Returning to <FIG>, EHT-SIG field <NUM> of EHT basic PPDU <NUM> may include remaining version dependent bits. It has a variable MCS and variable length. EHT-SIG field <NUM> has a Common field followed by a User Specific field which together are referred to as an EHT-SIG content channel. The User Specific field comprises one or more user field. The Common field comprises a first part and may comprise a second part. The first part comprises common information to all scheduled STA(s) except RU allocation information, whereas the second part may comprise the RU allocation information. The first part contains a determined number of data bits and may be the same across all EHT-SIG content channels; whereas the second part may be different among the EHT-SIG content channels.

Unlike U-SIG field <NUM>, the format of EHT-SIG field <NUM> depends on whether EHT basic PPDU <NUM> is transmitted to a single STA or multiple STAs. In an event of EHT basic PPDU <NUM> transmitted to a single STA, there will be a single EHT-SIG content channel regardless of the BW of EHT basic PPDU <NUM>, which is duplicated for each <NUM> frequency segment. In an event of EHT basic PPDU <NUM> transmitted to multiple STAs, there is one or two EHT-SIG content channels depending on the BW of EHT basic PPDU <NUM>. Specifically, e EHT-SIG field <NUM> comprising the Common field and the User Specific field are separately encoded on each L × <NUM> frequency segment, where L = <NUM> or <NUM>.

<FIG> shows a table of how the number of EHT-SIG content channels depends on the bandwidth and the value of L when EHT basic PPDU <NUM> is transmitted to multiple STAs. As shown in <FIG>, in an aspect where the BW of EHT basic PPDU <NUM> is <NUM>, L can only be <NUM> because EHT-SIG field <NUM> is encoded on a per-<NUM> basis and there will be only one EHT-SIG content channel. In an aspect where the BW of EHT basic PPDU <NUM> is <NUM>, L may be assigned by the AP the value of <NUM> or <NUM>. If L is set to "<NUM>", there will be two EHT-SIG content channels. If L is set to "<NUM>", there will be only one EHT-SIG content channel. In an aspect where the BW of EHT basic PPDU <NUM> is <NUM>, <NUM>+<NUM>, <NUM>, <NUM>+<NUM>, <NUM>, <NUM>+<NUM> or <NUM>, there will be two EHT-SIG content channels regardless of the value of L. More details will be provided below.

<FIG> shows a diagram of mapping of the one or two EHT-SIG content channels in a <NUM> EHT basic PPDU. The number of EHT-SIG content channels depends on the bandwidth and the value of L as shown in <FIG>. A <NUM> channel comprises two <NUM> frequency segments. When L = <NUM>, there will be two EHT-SIG content channels (namely, EHT-SIG content channel <NUM> and EHT-SIG content channel <NUM>) which are transmitted in the <NUM>st and <NUM>nd <NUM> frequency segments, respectively. When L = <NUM>, there will be only one EHT-SIG content channel.

<FIG> shows a diagram of mapping of the two EHT-SIG content channels (namely EHT-SIG content channel <NUM> and EHT-SIG content channel <NUM>) in an <NUM> EHT basic PPDU. When L = <NUM>, in an <NUM> channel comprising four <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st and <NUM>rd <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd and <NUM>th <NUM> frequency segments. When L = <NUM>, in an <NUM> channel comprising two <NUM> frequency segments, EHT-SIG content channel <NUM> is transmitted in the <NUM>st <NUM> frequency segment while EHT-SIG content channel <NUM> is transmitted in the <NUM>nd <NUM> frequency segment.

<FIG> shows a diagram of mapping of the two EHT-SIG content channels in an <NUM>+<NUM> or <NUM> EHT basic PPDU. When L = <NUM>, in an <NUM>+<NUM> or <NUM> channel comprising eight <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st, <NUM>rd, <NUM>th and <NUM>th <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd, <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments. When L = <NUM>, in an <NUM>+<NUM> or <NUM> channel comprising four <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st and <NUM>rd <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd and <NUM>th <NUM> frequency segments.

<FIG> shows a diagram of mapping of the two EHT-SIG content channels in a <NUM>+<NUM> or <NUM> EHT basic PPDU. When L = <NUM>, in a <NUM>+<NUM> or <NUM> channel comprising twelve <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st, <NUM>rd, <NUM>th, <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd, <NUM>th, <NUM>th <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments. When L = <NUM>, in a <NUM>+<NUM> or <NUM> channel comprising six <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st, <NUM>rd and <NUM>th <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd, <NUM>th and <NUM>th <NUM> frequency segments.

<FIG> shows a diagram of mapping of the two EHT-SIG content channels in a <NUM>+<NUM> or <NUM> EHT basic PPDU. When L = <NUM>, in a <NUM>+<NUM> or <NUM> channel comprising sixteen <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st, <NUM>rd, <NUM>th, <NUM>th, <NUM>th, <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd, <NUM>th, <NUM>th <NUM>th, <NUM>th, <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments. When L = <NUM>, in a <NUM>+<NUM> or <NUM> channel comprising eight <NUM> frequency segments, EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>st, <NUM>rd, <NUM>th and <NUM>th <NUM> frequency segments while EHT-SIG content channel <NUM> is duplicated and transmitted in the <NUM>nd, <NUM>th, <NUM>th and <NUM>th <NUM> frequency segments.

According to various aspects of the present disclosure, U-SIG field <NUM> comprises punctured channel information. There are two options for punctured channel information to be carried in U-SIG field <NUM>: (i) punctured channel information is carried in a Punctured Channel Info field; or (ii) punctured channel information, together with bandwidth information, is carried in a BW field. For example, under option <NUM>, i.e. punctured channel information and BW information are carried in a BW field in U-SIG field <NUM>, the BW field of U-SIG field <NUM> is set to "<NUM>" for <NUM>, "<NUM>" for <NUM>, "<NUM>" for <NUM> non-preamble puncturing mode, "<NUM>" for <NUM> and <NUM>+<NUM> non-preamble puncturing mode, "<NUM>" for <NUM> and <NUM>+<NUM> non-preamble puncturing mode, "<NUM>" for <NUM> and <NUM>+<NUM> non-preamble puncturing mode, "<NUM>" for <NUM> preamble puncturing mode, "<NUM>" for <NUM> and <NUM>+<NUM> preamble puncturing mode, "<NUM>" for <NUM> and <NUM>+<NUM> preamble puncturing mode, and "<NUM>" for <NUM> and <NUM>+<NUM> preamble puncturing mode. It is noted that a preamble puncturing mode is only allowed when a PPDU has a BW of <NUM> or higher.

According to a first aspect of the present disclosure, the Common field of EHT-SIG field <NUM> may comprise supplemental punctured channel information, depending on the mode of transmission of EHT basic PPDU <NUM>. In case of EHT basic PPDU <NUM> used for full bandwidth SU or MU-MIMO transmission, EHT-SIG field <NUM> does not comprise supplemental punctured channel information and RU allocation information. In case of EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission, EHT-SIG field <NUM> comprises supplemental punctured channel information but does not comprise RU allocation information, and the punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM> jointly indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. In case of EHT basic PPDU <NUM> used for OFDMA transmission, EHT-SIG field <NUM> does not comprise supplemental punctured channel information but comprise RU allocation information. The punctured channel information in U-SIG field <NUM> and RU allocation information in EHT-SIG field <NUM> jointly indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. Specifically, RU allocation information in EHT-SIG field <NUM> may indicate one or more <NUM> subchannel is not allocated. The one or more <NUM> subchannel which is not allocated has the same effect as the one or more <NUM> subchannel which is punctured.

With such EHT basic PPDU configuration with U-SIG field <NUM> comprising punctured channel information and EHT-SIG field <NUM> comprising supplemental punctured channel information, as much punctured channel information as possible can advantageously be obtained at the earliest time.

According to the first aspect of the present disclosure, different EHT-SIG compression modes may be enabled depending on the necessary information contained in EHT-SIG field <NUM> of EHT basic PPDU <NUM>. There may be three different EHT-SIG compression modes: (i) compression mode <NUM> used for OFDMA transmission, where the Common field of EHT-SIG field <NUM> comprises RU allocation information but does not comprise supplemental punctured channel information; (ii) compression mode <NUM> used for full bandwidth SU or MU-MIMO where the Common field of EHT-SIG field <NUM> does not comprise RU allocation information and supplemental punctured channel information; and (iii) compression mode <NUM> used for punctured SU or MU-MIMO transmission, where the Common field of EHT-SIG field <NUM> does not comprise RU allocation information but comprise supplemental punctured channel information. In various aspects below, EHT-SIG compression mode <NUM> refers to no compression on EHT-SIG field <NUM>.

In an aspect, EHT-SIG compression mode may be indicated in EHT-SIG Compression field and BW field of U-SIG field <NUM>. Table <NUM> depicts how various EHT-SIG compression modes are indicated in EHT-SIG Compression field and BW field of U-SIG field <NUM>. For EHT-SIG compression mode <NUM> used for OFDMA transmission, the EHT-SIG Compression field value is "<NUM>", regardless of the BW of EHT basic PPDU <NUM>. The Common field of EHT-SIG field <NUM> comprises RU allocation information but does not comprise supplemental punctured channel information. For EHT-SIG compression mode <NUM> used for full bandwidth SU or MU-MIMO transmission, the EHT-SIG Compression field value is "<NUM>" and the BW field value is one of "<NUM>" to "<NUM>" (i.e. non-preamble puncturing mode). The Common field of EHT-SIG field <NUM> does not comprise RU allocation information and supplemental punctured channel information. For EHT-SIG compression mode <NUM> used for punctured SU or MU-MIMO transmission, the EHT-SIG Compression field value is "<NUM>" and the BW field value is one of "<NUM>" to "<NUM>" (i.e. preamble puncturing mode). The Common field of EHT-SIG field <NUM> does not comprise RU allocation information but comprise supplemental punctured channel information.

Further, SU or MU-MIMO transmission is indicated through the Number Of EHT-SIG Symbols Or Non-OFDMA Users field of U-SIG field <NUM> when EHT-SIG Compression field is set to <NUM>. Specifically, a value of "<NUM>" in the Number Of EHT-SIG Symbols Or Non-OFDMA Users field indicates a SU transmission.

<FIG> depicts a flow diagram <NUM> illustrating processing of a received EHT basic PPDU <NUM> in an AP or a STA according to the first aspect. The process may start through determining if the EHT-SIG Compression field of U-SIG field <NUM> of received EHT basic PPDU <NUM> is set to "<NUM>". If it is set to "<NUM>", step <NUM> is carried out; otherwise step <NUM> is carried out. In step <NUM>, EHT-SIG compression mode <NUM> is determined, and then in step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> may be obtained from punctured channel information and RU allocation information which are respectively obtained from U-SIG field <NUM> and EHT-SIG field <NUM>. Returning to step <NUM>, the process may continue through determining if BW field is set to a value of large than "<NUM>". If the BW field is not set to a value larger than "<NUM>", EHT-SIG compression mode <NUM> is determined in step <NUM>, indicating a full bandwidth SU or MU-MIMO transmission; otherwise, step <NUM> is carried out. In step <NUM>, EHT-SIG compression mode <NUM> is determined, indicating a punctured SU or MU-MIMO transmission, and then in step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is obtained from punctured channel information and supplemental punctured channel information which are respectively obtained from U-SIG field <NUM> and EHT-SIG field <NUM>.

Returning to EHT-SIG field <NUM>, example format of the first part of Common field of EHT-SIG field <NUM> is illustrated in table <NUM>. As indicated above, the first part of Common field comprises common information to all scheduled STA(s) except RU allocation information and contains a determined number of data bits which may be the same across all EHT-SIG content channels. Specifically, the first part of Common field may comprise a Low Density Parity Code (LDPC) Extra Symbol Segment subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, a Doppler subfield, a GI-LTF Size subfield, an EHT-LTF Mode subfield and a Number Of EHT-LTF Symbols And Midamble Periodicity subfield.

Example formats of the second part of Common field of EHT-SIG field <NUM> are illustrated in tables <NUM> and <NUM>. The second part of Common field of EHT-SIG field <NUM> may comprise RU allocation information and/or supplemental punctured channel information and may be different among the EHT-SIG content channels. Similar to punctured channel information and bandwidth information which can be contained in a single field or two separate fields in U-SIG field <NUM>, RU allocation information and supplemental punctured channel information can be contained in a single field of the second part of the Common field (e.g. RU Allocation Or Supplemental Punctured Channel Info field), where its field size depends on BW and compression mode, as illustrated in table <NUM>. Alternatively, RU allocation information and supplemental punctured channel information can be contained in two separate fields of the second part of the Common field (e.g. RU Allocation Info field and Supplemental Punctured Channel Info field, respectively), where field size of each RU Allocation Info field and Supplemental Punctured Channel Info field depends on BW, as illustrated in table <NUM>. Specifically, the second part of Common field of EHT-SIG field <NUM> may comprise a bitmap, for example <NUM> bits for the BW of <NUM>, <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, <NUM> bits for the BW of <NUM> or <NUM>+<NUM> and <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, to carry the supplemental punctured channel information. The bitmap indicates whether each <NUM> subchannel which is not primary <NUM> is punctured. It is noted that a preamble puncturing mode is only allowed when an EHT basic PPDU has a BW of <NUM> or higher. It is also noted that under EHT-SIG compression mode <NUM>, EHT-SIG field <NUM> does not comprise both RU allocation information and supplemental punctured channel information.

Example format of User field of EHT-SIG field <NUM> for non-MU MIMO allocation and MU-MIMO allocation are illustrated in tables <NUM> and <NUM> respectively. For non-MU MIMO allocation, a User field may comprise a STA ID field, an EHT MCS field, a DCM field, a NSTS field, a Coding field and a Beamformed field; whereas for MU-MIMO allocation, a User field may comprise a STA ID field, an EHT MCS field, a Spatial Configuration field and a Coding field. It should be appreciable and apparent to one of ordinary skilled in the art that the standard definitions, protocols and functions of all fields of Common field and User field listed in tables <NUM> to <NUM>, <NUM> and <NUM> can be obtained from the <NUM>. 11ax specification, unless specified otherwise in this specification.

A User Specific field may consist one or more User Block field(s), and each User Block field comprises one or two User fields. For example, as illustrated in <FIG> and <FIG>, a User Specific field may contain <NUM> User Block fields <NUM>, <NUM> and <NUM>, the User Block field <NUM> comprising two user fields like User field <NUM> and User field <NUM>, User Block field <NUM> comprising two user fields like User field <NUM> and User field <NUM>, and User Block field <NUM> comprising one User field <NUM>, where the one or two user fields in each User Block fields <NUM> to <NUM> is appended with a CRC field for detecting error and tail bits. In an aspect, the last User Block may consist of one or two user fields depending on the total number of user fields that are allowed in the User Specific field referring to an odd or even number.

According to the present disclosure, the first part and the second part of Common field of EHT-SIG field <NUM> or EHT-SIG content channel can be jointly encoded or separately encoded, resulting in different EHT-SIG field format options. <FIG> depicts an example format of an EHT-SIG content channel of EHT-SIG field <NUM> where the first part 702a and the second part 702b of the Common field <NUM> are jointly encoded (Option <NUM>). In this option, the first part 702a of the Common field <NUM> is followed by the second part 702b of the Common field <NUM> to which a single block of CRC field and tail bits are appended. Such EHT-SIG field format with jointly encoded Common field may advantageously reduce the number of CRC fields and tail bits used in EHT-SIG field, thus reduce signaling overhead.

<FIG> depicts another example format of an EHT-SIG content channel or EHT-SIG field <NUM> where the first part 702a and the second part 702b of the Common field <NUM> are separately encoded (Option <NUM>). In this option, a CRC field and tail bits may be included at the end of each separately encoded field, i.e. the first part 702a and the second part 702b of the Common field <NUM>. In an aspect, when EHT-SIG compression mode <NUM> is enabled, for example the EHT-SIG Compression field of U-SIG field <NUM> is set to "<NUM>" and the BW field of U-SIG field <NUM> is set to one of "<NUM>" to "<NUM>" indicating a full bandwidth SU or MU-MIMO transmission, the second part of the Common field 702b comprising RU allocation information and supplemental punctured channel information may not be present. In this case, both format option <NUM> and option <NUM> of EHT-SIG field <NUM> or EHT-SIG content channel are identical.

Yet in another aspect, the first part 702a and the second part 702b of the Common field of an EHT-SIG content channel or EHT-SIG field <NUM> may be separately encoded or jointly encoded depending on which compression mode is enabled. When EHT-SIG compression mode <NUM> is enabled, the first part 702a and the second part 702b of Common field of EHT-SIG field <NUM> are separately encoded; whereas when EHT-SIG compression mode <NUM> is enabled, the first part 702a and the second part 702b of Common field are jointly encoded to reduce EHT-SIG field signaling overhead.

According to a second aspect of the present disclosure, when an EHT basic PPDU <NUM> is used for punctured SU or MU-MIMO transmission, if the punctured channel information in U-SIG field <NUM> is able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information. On the other hand, if the punctured channel information in U-SIG field <NUM> is not able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, EHT-SIG field <NUM> comprises supplemental punctured channel information that, together with the punctured channel information in U-SIG field <NUM>, indicates a channel puncturing pattern that is applied to EHT basic PPDU <NUM>.

In one aspect, the punctured channel information in U-SIG field <NUM> may be able to indicate all channel puncturing patterns that are allowed for up to a determined BW (e.g. <NUM>). When an EHT basic PPDU <NUM> is used for punctured SU or MU-MIMO transmission, if the BW of EHT basic PPDU <NUM> is less than or equal to the determined BW, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information.

In another aspect, the punctured channel information in U-SIG field <NUM> may be able to indicate all channel puncturing patterns that are allowed for up to a determined BW (e.g. <NUM>) and a part of channel puncturing patterns for BWs larger than the determined BW. When an EHT basic PPDU <NUM> is used for punctured SU or MU-MIMO transmission, if the BW of EHT basic PPDU <NUM> is less than or equal to the determined BW, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information. If the BW of EHT basic PPDU <NUM> is larger than the determined BW, and the part of channel puncturing patterns for BWs larger than the determined BW, which the punctured channel information in U-SIG field <NUM> is able to indicate, includes a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information.

In yet another aspect, the punctured channel information in U-SIG field <NUM> may be able to indicate a plurality of channel puncturing patterns that are allowed for different BWs. When an EHT basic PPDU <NUM> is used for punctured SU or MU-MIMO transmission, if the plurality of channel puncturing patterns for different BWs, which the punctured channel information in U-SIG field <NUM> is able to indicate, includes a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information.

The effect of such implementation allows compression mode <NUM> to be enabled in more use cases and thus EHT-SIG field signaling overhead can be minimized. Specifically, according to the second aspect, there may be three different EHT-SIG compression modes for EHT-SIG field <NUM> of EHT basic PPDU <NUM>: (i) compression mode <NUM> (i.e. no compression) where the Common field 702b of EHT-SIG field <NUM> comprises RU allocation information used for OFDMA transmission but does not comprise supplemental punctured channel information; (ii) compression mode <NUM> used for SU or MU-MIMO transmission where the Common field 702b of EHT-SIG field <NUM> does not comprise RU allocation information and supplemental punctured channel information; and (iii) compression mode <NUM> used for SU or MU-MIMO transmission where the Common field 702b of EHT-SIG field <NUM> does not comprise RU allocation information but comprises supplemental punctured channel information.

In particular, EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where supplemental punctured channel information in EHT-SIG field <NUM> is not required. Example use cases include an EHT basic PPDU <NUM> used for full bandwidth SU or MU-MIMO transmission (use case <NUM>); or used for punctured SU or MU-MIMO transmission when the punctured channel information in U-SIG field <NUM> is able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM> (use case <NUM>). Under EHT-SIG compression mode <NUM>, the Common field 702b of EHT-SIG field <NUM> does not comprise both RU allocation information and supplemental punctured channel information.

EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where supplemental punctured channel information is required in EHT-SIG <NUM>. Example use case is an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where the punctured channel information in U-SIG field <NUM> is not able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. Under EHT-SIG compression mode <NUM>, the Common field 702b of EHT-SIG field <NUM> does not comprise RU allocation information but comprises supplemental punctured channel information.

According to the second aspect, the <NUM>nd use case of EHT-SIG compression mode <NUM> and the use case of EHT-SIG compression mode <NUM> depend on the content of punctured channel information in U-SIG field <NUM>. For example, assume that the punctured channel information in U-SIG field <NUM> is able to indicate whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and whether at least one <NUM> subchannel outside primary <NUM> is punctured. Under this assumption, the <NUM>nd use case of EHT-SIG compression mode <NUM> can be further divided into two use cases: an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission when the BW of EHT basic PPDU <NUM> is <NUM> (use case <NUM>); and an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission when the BW of EHT basic PPDU <NUM> is larger than <NUM> and no <NUM> subchannel outside primary <NUM> is punctured (use case <NUM>). On the other hand, the use case of EHT-SIG compression mode <NUM> is an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission when the BW of EHT basic PPDU <NUM> is larger than <NUM> and at least one <NUM> subchannel outside primary <NUM> is punctured.

Table <NUM> depicts an example format of U-SIG field <NUM> in EHT basic PPDU <NUM>. The U-SIG field <NUM> comprises two parts: U-SIG1 and U-SIG2, each of the two parts containing <NUM> data bits. The U-SIG1 comprises all version independent bits such as a PHY Version Identifier field, an UL/DL Flag field, a BSS Color field, a TXOP Duration field and a BW field, a part of version dependent bits such as a PPDU Type field and some of EHT-SIG related bits, such as an EHT-SIG Compression field and an EHT-SIG DCM field. The U-SIG2 comprises the remaining version dependent bits such as an EHT-SIG EHT MCS field, a Number Of EHT-SIG Symbols Or Non-OFDMA Users field, a Spatial Reuse field, and a Punctured Channel Info field followed by reserved bits, a CRC field and tail bits. Unless specified otherwise in this specification, it should be appreciable and apparent to one of ordinary skilled in the art that the standard definitions, protocols and functions of most of the fields in the U-SIG field <NUM> listed in table <NUM> can be obtained from the <NUM>. 11ax specification.

Specifically, the Punctured Channel Info field is a <NUM>-bit bitmap, of which three least significant bits (LSBs) indicates whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and a most significant bit (MSB) indicates whether at least one <NUM> subchannel outside primary <NUM> is punctured, which is reserved for the BW of <NUM>. The BW field of U-SIG field <NUM> is set to "<NUM>" for <NUM>, "<NUM>" for <NUM>, "<NUM>" for <NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>.

In an aspect, EHT-SIG compression mode may be indicated in EHT-SIG Compression field, Punctured Channel Info field and BW field of U-SIG field <NUM>. Table <NUM> depicts how various EHT-SIG compression modes are indicated in EHT-SIG Compression field, Punctured Channel Info field and BW field of U-SIG field <NUM>. In particular, when the EHT-SIG Compression field value is "<NUM>" indicating an OFDMA transmission, EHT-SIG compression mode <NUM> is enabled regardless of the Punctured Channel Info field value and the BW field value.

Table <NUM> is plotted based on an assumption that the punctured channel information in U-SIG field <NUM> is able to indicate whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and whether at least one <NUM> subchannel outside primary <NUM> is punctured. When the EHT-SIG Compression field value is "<NUM>", Punctured Channel Information field has all non-reserved bits set to "<NUM>" indicating a non-preamble puncturing mode, EHT-SIG compression mode <NUM> can be enabled under use case <NUM> regardless of the BW field value. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>", and BW field value is "<NUM>" (BW = <NUM>), at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission can be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>" and MSB of Punctured Channel Info field is set to "<NUM>", and BW field value is larger than "<NUM>" (BW > <NUM>), at least one <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and no <NUM> subchannel outside primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission can also be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>.

When the EHT-SIG Compression field value is "<NUM>", MSB of Punctured Channel Info field is set to "<NUM>" and BW field value is larger than "<NUM>" (BW > <NUM>), at least one <NUM> subchannel outside primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission can be determined based on punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM>.

Further, SU or MU-MIMO transmission can be indicated through the Number Of EHT-SIG Symbols Or Non-OFDMA Users field of U-SIG field <NUM> when EHT-SIG Compression field is set to <NUM>. Specifically, a value of "<NUM>" in the Number Of EHT-SIG Symbols Or Non-OFDMA Users field indicates a SU transmission.

Example formats of the second part of Common field 702b of EHT-SIG field <NUM> are illustrated in tables <NUM> and <NUM>. RU allocation information and supplemental punctured channel information may be included in a single field of the second part of the Common field 702b of EHT-SIG field <NUM> (e.g. RU Allocation Or Supplemental Punctured Channel Info field), where its field size depends on BW and compression mode, as illustrated in table <NUM>. Alternatively, RU allocation information and supplemental punctured channel information can be contained in two separate fields of the second part of the Common field 702b (e.g. RU Allocation Info field and Supplemental Punctured Channel Info field, respectively), where field size of each RU Allocation Info field and Supplemental Punctured Channel Info field depends on BW, as illustrated in table <NUM>. Specifically, the second part of Common field 702b of EHT-SIG field <NUM> may comprise a bitmap, for example <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, <NUM> bits for the BW of <NUM> or <NUM>+<NUM> and <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, to carry the supplemental punctured channel information. The bitmap indicates whether each <NUM> subchannel outside primary <NUM> is punctured.

The first part of the Common field 702a and the User field of the EHT-SIG field <NUM> may be identical to those depicted in tables <NUM> to <NUM>. It should be appreciable and apparent to one of ordinary skilled in the art that the standard definitions, protocols and functions of all fields of Common field and User field listed in tables <NUM> to <NUM> can be obtained from the <NUM>. 11ax specification without further elaboration, unless specified otherwise in this specification.

<FIG> depicts a flow diagram <NUM> illustrating processing of a received EHT basic PPDU <NUM> in an AP or a STA according to the second aspect. The process may start in step <NUM> through determining if EHT-SIG Compression field is set to "<NUM>" indicating a SU or MU-MIMO transmission. If the EHT-SIG Compression field is not set to "<NUM>", in step <NUM>, EHT-SIG compression mode <NUM> is determined, and in step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM> and RU allocation information in EHT-SIG field <NUM>, and the process may end.

If the EHT-SIG Compression field is set to "<NUM>", step <NUM> is carried out. In step <NUM>, it is determined if the BW field is set to a value larger than "<NUM>" (BW > <NUM>). If the BW field is not set to a value larger than "<NUM>", step <NUM> is carried out. In step <NUM>, it is then determined if the BW field is set to "<NUM>" (BW = <NUM>) and at least one of three LSBs of Punctured Channel Info field is set to "<NUM>". If the BW is not set to "<NUM>" or all three LSBs of Punctured Channel Info field are set to "<NUM>", in step <NUM>, use case <NUM> of EHT-SIG compression mode <NUM> is determined, i.e. full bandwidth SU or MU-MIMO transmission, and the process may end. If the BW field is set to "<NUM>" or at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>" indicating at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured, use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>.

Returning to step <NUM>, if it is determined that the BW field is set to a value larger than "<NUM>" (BW > <NUM>), step <NUM> is carried out. In step <NUM>, it is further determined if the MSB of the Punctured Channel Info field is set to "<NUM>" indicating at least one <NUM> subchannel outside primary <NUM> is punctured. If the MSB of the Punctured Channel Info field is not set to "<NUM>", use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>. If the MSB of the Punctured Channel Info field is set to "<NUM>", EHT-SIG compression mode <NUM> is determined in step <NUM>. When use case <NUM> or use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM> or <NUM> respectively, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM>. On the other hand, when EHT-SIG compression mode <NUM> is determined in step <NUM>, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM>.

According to a third aspect of the present disclosure, the abovementioned punctured channel signalling for punctured SU or MU-MIMO transmission can be applied to punctured OFDMA transmission as well. Specifically, when an EHT basic PPDU <NUM> is used for punctured OFDMA transmission, EHT-SIG field <NUM> comprises RU allocation information. If the punctured channel information of U-SIG field <NUM> is able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, EHT-SIG field <NUM> does not comprise supplemental punctured channel information. If the punctured channel information of U-SIG field <NUM> is not able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, EHT-SIG field <NUM> comprise supplemental punctured channel information. In this case, punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM> jointly indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. The effect of which is that less RU allocation information may be required in case of punctured OFDMA transmission and thus reduce EHT-SIG field signalling overhead.

In an aspect, the punctured channel information in U-SIG field <NUM> may be able to indicate all channel puncturing patterns that are allowed for up to a determined BW (e.g. <NUM>). When an EHT basic PPDU <NUM> is used for punctured SU, MU-MIMO or OFDMA transmission, if the BW of EHT basic PPDU <NUM> is less than or equal to the determined BW, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information.

In another aspect, the punctured channel information in U-SIG field <NUM> may be able to indicate all channel puncturing patterns that are allowed for up to a determined BW (e.g. <NUM>) and a part of channel puncturing patterns for BWs larger than the determined BW. When an EHT basic PPDU <NUM> is used for punctured SU, MU-MIMO or OFDMA transmission, if the BW of EHT basic PPDU <NUM> is less than or equal to the determined BW, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information. If the BW of EHT basic PPDU <NUM> is larger than the determined BW and the part of channel puncturing patterns for BWs larger than the determined BW, which the punctured channel information in U-SIG field <NUM> is able to indicate, includes a channel puncturing pattern that is applied to EHT basic PPDU <NUM>, supplemental punctured channel information is not required therefore EHT-SIG field <NUM> may not comprise supplemental punctured channel information.

According to the third aspect, there may be four different EHT-SIG compression modes for EHT-SIG field <NUM> of EHT Basic PPDU <NUM>: (i) compression mode <NUM> where the Common field of EHT-SIG field <NUM> comprises RU allocation information but does not comprise supplemental punctured channel information; (ii) compression mode <NUM> where the Common field of EHT-SIG field <NUM> does not comprise RU allocation information and supplemental punctured channel information; (iii) compression mode <NUM> where the Common field of EHT-SIG field <NUM> does not comprise RU allocation information but comprise supplemental punctured channel information; and (iv) compression mode <NUM> where the Common field of EHT-SIG field <NUM> comprises both RU allocation information and supplemental punctured channel information.

In particular, EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for OFDMA transmission where supplemental punctured channel information in EHT-SIG field <NUM> is not required. Example use cases include an EHT basic PPDU <NUM> used for full bandwidth OFDMA transmission (use case <NUM> of compression mode <NUM>); and punctured OFDMA transmission when the punctured channel information in U-SIG field <NUM> is able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM> (use case <NUM> of compression mode <NUM>). Under EHT-SIG compression mode <NUM>, the Common field of EHT-SIG field <NUM> comprises RU allocation information but does not comprise supplemental punctured channel information.

On the other hand, EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for punctured OFDMA transmission where the punctured channel information in U-SIG field <NUM> is not able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. Since the punctured channel information of U-SIG field <NUM> is not able to indicate the channel puncturing pattern that is applied to EHT basic PPDU <NUM>, supplemental punctured channel information in EHT-SIG field <NUM> is required. Under EHT-SIG compression mode <NUM>, the Common field of EHT-SIG field <NUM> comprises both RU allocation information and supplemental punctured channel information. Such implementation of compression mode <NUM> in case of punctured OFDMA transmission may advantageously reduce EHT-SIG field signaling overhead since no RU allocation information is required for punctured <NUM> subchannel(s).

EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where supplemental punctured channel information in EHT-SIG field <NUM> is not required. Example use cases include an EHT basic PPDU <NUM> used for full bandwidth SU or MU-MIMO transmission (use case <NUM> of compression mode <NUM>); and an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission when the punctured channel information in U-SIG field <NUM> is able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM> (use case <NUM> of compression mode <NUM>). Under EHT-SIG compression mode <NUM>, the Common field 702b of EHT-SIG field <NUM> does not comprise both RU allocation information and supplemental punctured channel information.

EHT-SIG compression mode <NUM> is enabled for an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where supplemental punctured channel information is required in EHT-SIG <NUM>. Example use case is an EHT basic PPDU <NUM> used for SU or MU-MIMO transmission where the punctured channel information in U-SIG field <NUM> is not able to indicate a channel puncturing pattern that is applied to EHT basic PPDU <NUM>. Under EHT-SIG compression mode <NUM>, the Common field 702b of EHT-SIG field <NUM> does not comprise RU allocation information but comprise supplemental punctured channel information.

The <NUM>nd use case of EHT-SIG compression mode <NUM> or compression mode <NUM> and the use case of EHT-SIG compression mode <NUM> or compression mode <NUM> depend on the content of punctured channel information in U-SIG field <NUM>. For example, by assuming that the punctured channel information in U-SIG field <NUM> is able to indicate whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and whether at least one <NUM> subchannel outside primary <NUM> is punctured, the <NUM>nd use case of EHT-SIG compression mode <NUM> or <NUM> can be further divided into two use cases: an EHT basic PPDU used for punctured SU, MU-MIMO or OFDMA transmission when the BW of EHT basic PPDU <NUM> is <NUM> (use case <NUM>); and an EHT basic PPDU <NUM> used for punctured SU, MU-MIMO or OFDMA transmission when the BW of EHT basic PPDU <NUM> is larger than <NUM> and no <NUM> subchannel outside primary <NUM> is punctured (use case <NUM>).

Table <NUM> depicts an example format of U-SIG field <NUM> in EHT basic PPDU <NUM>. U-SIG field <NUM> comprises two parts: U-SIG1 and U-SIG2, each of the two parts containing <NUM> data bits. U-SIG1 comprises all version independent bits such as a PHY Version Identifier field, an UL/DL Flag field, a BSS Color field, a TXOP Duration field and a BW field, a part of version dependent bits such as a PPDU Type field and some of EHT-SIG related bits such as an EHT-SIG Compression field and an EHT-SIG DCM field. U-SIG2 comprises the remaining version dependent bits such as an EHT-SIG EHT MCS field, a Number Of EHT-SIG Symbols Or Non-OFDMA Users field, a Spatial Reuse field, and a Punctured Channel Info field followed by reserved bits, a CRC field and tail bits. Unless specified otherwise in this specification, it should be appreciable and apparent to one of ordinary skilled in the art that the standard definitions, protocols and functions of most of the fields in U-SIG field <NUM> listed in table <NUM> can be obtained from the <NUM>. 11ax specification.

Specifically, the Punctured Channel Info field is a <NUM>-bit bitmap, of which three LSBs indicates whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and a MSB indicates whether at least one <NUM> subchannel outside primary <NUM> is punctured, which is reserved for the BW of <NUM>. the BW field of U-SIG field <NUM> is set to "<NUM>" for <NUM>, "<NUM>" for <NUM>, "<NUM>" for <NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>, "<NUM>" for <NUM> and <NUM>+<NUM>.

In an aspect, the EHT-SIG compression mode may be indicated in EHT-SIG Compression field, Punctured Channel Info field and BW field of U-SIG field <NUM>. Table <NUM> depicts how various EHT-SIG compression modes are indicated in EHT-SIG Compression field, Punctured Channel Info field and BW field of U-SIG field <NUM> according to the third aspect of the present disclosure. The EHT-SIG Compression field is set to "<NUM>" indicating an OFDMA transmission and "<NUM>" indicating a SU or MU-MIMO transmission.

Table <NUM> is plotted based on an assumption that punctured channel information in U-SIG field <NUM> is able to indicate whether each <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and whether at least one <NUM> subchannel outside primary <NUM> is punctured. When the EHT-SIG Compression field value is "<NUM>", Punctured Channel Info field has all non-reserved bits set to "<NUM>" indicating a non-preamble puncturing mode of SU or MU-MIMO transmission, EHT-SIG compression mode <NUM> can be enabled under use case <NUM> regardless of the BW field value. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>", and BW field value is "<NUM>" (BW = <NUM>), at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission can be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>" and MSB of Punctured Channel Info field is set to "<NUM>", and BW field value is larger than "<NUM>" (BW > <NUM>), at least one <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and no <NUM> subchannel outside primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured SU or MU-MIMO transmission can also be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>.

When the EHT-SIG Compression field value is "<NUM>", Punctured Channel Information field has all non-reserved bits set to "<NUM>" indicating a non-preamble puncturing mode of OFDMA transmission, EHT-SIG compression mode <NUM> can be enabled under use case <NUM> regardless of the BW field value. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>", and BW field value is "<NUM>" (BW = <NUM>), at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured OFDMA transmission can be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>. When the EHT-SIG Compression field value is "<NUM>", at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM>" and MSB of Punctured Channel Info field is set to "<NUM>", and BW field value is larger than "<NUM>" (BW > <NUM>), at least one <NUM> subchannel within primary <NUM> which is not primary <NUM> is punctured and no <NUM> subchannel outside primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured OFDMA transmission can also be determined solely based on punctured channel information in U-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM> under use case <NUM>.

When the EHT-SIG Compression field value is "<NUM>", MSB of Punctured Channel Info field is set to "<NUM>" and BW field value is larger than "<NUM>" (BW > <NUM>), at least one <NUM> subchannel outside primary <NUM> is punctured. In this case, a channel puncturing pattern that is applied to an EHT basic PPDU <NUM> used for punctured OFDMA transmission can be determined based on punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM>, and thus EHT-SIG compression mode <NUM> can be enabled for EHT basic PPDU <NUM>.

The supplemental punctured channel information may be carried in a signaling field (e.g. Supplemental Punctured Channel Info field) in the first part of the Common field 702a of EHT-SIG field <NUM>, where the field size depends on the BW of EHT basic PPDU <NUM>. The Supplemental Punctured Channel Info field may contain supplemental punctured channel information on all <NUM> subchannels outside primary <NUM>. In one option, such Supplemental Punctured Channel Info field is independent of EHT-SIG content channels thus all EHT-SIG content channels contain the same Supplemental Punctured Channel Info field. The field may contain a bitmap which is <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, or <NUM> bits for the BW of <NUM> or <NUM>+<NUM>. The bitmap indicates whether each <NUM> subchannel outside primary <NUM> is punctured.

In another option, the Supplemental Punctured Channel Info field in an EHT-SIG content channel may contain supplemental punctured channel information on <NUM> subchannels outside primary <NUM> which are corresponding to only the EHT-SIG content channel. Such Supplemental Punctured Channel Info field may be dependent on EHT-SIG content channel and thus is different among all EHT-SIG content channels. The field may contain a bitmap which is <NUM> bits for the BW of <NUM> or <NUM>+<NUM>, <NUM> bits for the BW for <NUM> or <NUM>+<NUM> or <NUM> bits for the BW for <NUM> or <NUM>+<NUM>. As such, the second implementation option of the field may advantageously reduce EHT-SIG field signaling overhead.

Further, RU allocation may be contained in the second part of the Common field 702b of EHT-SIG field <NUM> (e.g. RU Allocation Info field), where its field size depends on the values of BW, Punctured Channel Infor field and Supplemental Punctured Channel Info fields since RU allocation information for punctured <NUM> subchannels is not required.

<FIG> and <FIG> depicts a flow diagram <NUM> illustrating processing of a received EHT basic PPDU <NUM> in an AP or a STA according to the third aspect. The process may start in step <NUM> through determining if EHT-SIG Compression field is set to "<NUM>". If the EHT-SIG Compression field is set to "<NUM>" indicating a SU or MU-MIMO transmission, step <NUM> is carried out where EHT-SIG compression mode <NUM> or <NUM> is determined, whereas if the EHT-SIG Compression field is set to "<NUM>" indicating an OFDMA transmission, step <NUM> is carried out where EHT-SIG compression mode <NUM> or <NUM> is determined. Further processing for the received EHT basic PPDU <NUM> used for OFDMA transmission subsequent to step <NUM> will be discussed in <FIG>.

Returning to step <NUM>, it is then determined if the BW field is set to a value larger than "<NUM>", a BW field value of "<NUM>" indicating a BW of <NUM>. If the BW field is not set to a value larger than "<NUM>", step <NUM> is carried out. In step <NUM>, it is then determined if the BW field is set to "<NUM>" and at least one of three LSBs of Punctured Channel Info field is set to "<NUM>". If the BW field is not set to "<NUM>" or all three LSBs of Punctured Channel Info field are set to "<NUM>", in step <NUM>, use case <NUM> of EHT-SIG compression mode <NUM> is determined, i.e. full bandwidth SU or MU-MIMO transmission, and the process may end. If the BW field is set to "<NUM>" or at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM> indicating at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured, use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>.

Returning to step <NUM>, if it is determined that the BW field is set to a value larger than "<NUM>", step <NUM> is carried out. In step <NUM>, it is further determined if MSB of the Punctured Channel Info field is set to "<NUM>" indicating at least one <NUM> subchannel outside primary <NUM> is punctured. If the MSB of the Punctured Channel Info field is not set to "<NUM>", use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>. If the MSB of the Punctured Channel Info field is set to "<NUM>", EHT-SIG compression mode <NUM> is determined in step <NUM>. When use case <NUM> or use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM> or <NUM> respectively, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM>. On the other hand, when EHT-SIG compression mode <NUM> is determined in step <NUM>, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM>.

Returning to step <NUM>, after EHT-SIG compression mode <NUM> or <NUM> is determined, step <NUM> is carried out. In step <NUM>, it is then determined if BW field is set to a value larger than "<NUM>". If the BW field is not set to a value larger than "<NUM>", step <NUM> is carried out. In step <NUM>, it is then determined if the BW field is set to "<NUM>" and at least one of three LSBs of Punctured Channel Info field is set to "<NUM>". If the BW is not set to "<NUM>" or all three LSBs of Punctured Channel Info field are set to "<NUM>", in step <NUM>, use case of <NUM> of EHT-SIG compression mode <NUM> is determined, i.e. full bandwidth OFDMA transmission, and the process may end. If the BW field is set to "<NUM>" or at least one of <NUM> LSBs of Punctured Channel Info field is set to "<NUM> indicating at least one <NUM> subchannel within <NUM> channel which is not primary <NUM> is punctured, use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>.

Returning to step <NUM>, if it is determined that BW field is set to a value larger than "<NUM>", step <NUM> is carried out. In step <NUM>, it is further determined if MSB of the Punctured Channel Info field is set to "<NUM>" indicating at least one <NUM> subchannel outside primary <NUM> is punctured. If the MSB of the Punctured Channel Info field is not set to "<NUM>", use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM>. If the MSB of the Punctured Channel Info field is set to "<NUM>", EHT-SIG compression mode <NUM> is determined in step <NUM>. When use case <NUM> or use case <NUM> of EHT-SIG compression mode <NUM> is determined in step <NUM> or <NUM> respectively, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM>. On the other hand, when EHT-SIG compression mode <NUM> is determined in step <NUM>, step <NUM> is carried out. In step <NUM>, a channel puncturing pattern that is applied to the received EHT basic PPDU <NUM> is determined from punctured channel information in U-SIG field <NUM> and supplemental punctured channel information in EHT-SIG field <NUM>.

<FIG> depicts an example format of an EHT TB PPDU <NUM>. The EHT TB PPDU <NUM> has a similar structure as that of EHT basic PPDU <NUM> but without EHT-SIG field <NUM>. The EHT TB PPDU <NUM> may include a L-STF, a L-LTF, a L-SIG field, a FIF, a U-SIG field <NUM>, an EHT-STF, an EHT-LTF, a Data field and a PE field. The L-STF, the L-LTF, the L-SIG, the RL-SIG and the U-SIG field <NUM> may be grouped as pre-EHT modulated fields, while the EHT-STF, the EHT-LTF, the Data field and the PE field may be grouped as EHT modulated fields. An EHT TB PPDU can be used for trigger-based communications that is in response to a soliciting triggering frame. For example, EHT TB PPDUs can be used for transmitting BA frames <NUM>, <NUM> by STAs <NUM>, <NUM> when EHT basic PPDU <NUM> is transmitted to STAs <NUM>, <NUM> and contains one or more triggering frame, as illustrated in <FIG>.

Table <NUM> depicts an example format of U-SIG field <NUM> of EHT TB PPDU <NUM>. Similar to EHT basic PPDU <NUM>, the U-SIG field <NUM> comprises two parts, U-SIG1 and U-SIG2, each comprising <NUM> data bits. In this aspect, all version independent bits may be included in U-SIG1. The first part of U-SIG field <NUM>, i.e. U-SIG1, comprises a PHY Version Identifier field, a UL/DL Flag field, a BSS Color field, a TXOP Duration field, a BW field and a PPDU Type field. The PHY Version Identifier field is used to identify the exact PHY version starting with <NUM>. The second part of U-SIG field <NUM>, i.e. U-SIG2, comprises Spatial Reuse <NUM> to <NUM> fields, followed by a CRC field and tail bits. Information of some of the field in U-SIG field <NUM> (e.g. BW field and Spatial Reuse <NUM> to <NUM> fields) can be copied from the corresponding triggering frame soliciting the transmission of EHT TB PPDU <NUM>. It should be appreciated and apparent to one of ordinary skilled in the art that that the standard definitions, protocols and functions of most of the fields in U-SIG field <NUM> of EHT TB PPDU <NUM> can be obtained from the <NUM>. 11ax specification.

<FIG> shows a configuration of a communication device <NUM>, for example an AP according to various aspects. Similar to the schematic example of the communication apparatus <NUM> shown in <FIG>, the communication apparatus <NUM> includes circuitry <NUM>, at least one radio transmitter <NUM>, at least one radio receiver <NUM>, at least one antenna <NUM> (for the sake of simplicity, only one antenna is depicted in <FIG>). The circuitry <NUM> may include at least one controller <NUM> for use in software and hardware aided execution of tasks that the controller <NUM> is designed to perform communication for control singling. The circuitry <NUM> may further include a transmission signal generator <NUM> and a receive signal processor <NUM>. The at least one controller <NUM> may control the transmission signal generator <NUM> and the receive signal processor <NUM>. The transmission signal generator <NUM> may include a frame generator <NUM>, a control signaling generator <NUM>, and a PPDU generator <NUM>. The frame generator <NUM> may generate MAC frames, e.g. data frames or triggering frames. The control signaling generator <NUM> may generate control signaling fields of PPDUs to be generated (e.g. U-SIG fields and EHT-SIG fields of EHT basic PPDUs). The PPDU generator <NUM> may generate PPDUs (e.g. EHT basic PPDUs).

The receive signal processor <NUM> may include a data demodulator and decoder <NUM>, which may demodulate and decode data portions of the received signals (e.g. data fields of EHT basic PPDUs or EHT TB PPDUs). The receive signal processor <NUM> may further include a control demodulator and decoder <NUM>, which may demodulate and decode control signaling portions of the received signals (e.g. U-SIG fields of EHT basic PPDUs or EHT TB PPDUs and EHT-SIG fields of EHT basic PPDUs). The at least one controller <NUM> may include a control signal parser <NUM> and a scheduler <NUM>. The scheduler <NUM> may determine RU information and user-specific allocation information for allocations of downlink SU or MU transmissions and triggering information for allocations of uplink MU transmissions. The control signal parser <NUM> may analyse the control signaling portions of the received signals and the triggering information for allocations of uplink MU transmissions shared by the scheduler <NUM> and assist the data demodulator and decoder <NUM> in demodulating and decoding the data portions of the received signals.

<FIG> shows a configuration of a communication apparatus <NUM>, for example a STA according to various aspects. Similar to the schematic example of communication apparatus <NUM> shown in <FIG>, the communication apparatus <NUM> includes circuitry <NUM>, at least one radio transmitter <NUM>, at least one radio receiver <NUM>, at least one antenna <NUM> (for the sake of simplicity, only one antenna is depicted in <FIG>). The circuitry <NUM> may include at least one controller <NUM> for use in software and hardware aided execution of tasks that the controller <NUM> is designed to perform communication for control signaling. The circuitry <NUM> may further include a receive signal processor <NUM> and a transmission signal generator <NUM>. The at least one controller <NUM> may control the receive signal processor <NUM> and the transmission signal generator <NUM>. The receive signal processor <NUM> may include a data demodulator and decoder <NUM> and a control demodulator and decoder <NUM>. The control demodulator and decoder <NUM> may demodulate and decode control signaling portions of the received signals (e.g. U-SIG fields and EHT-SIG fields of EHT basic PPDUs). The data demodulator and decoder <NUM> may demodulate and decode data portions of the received signals (e.g. data fields of ETH basic PPDUs) according to RU information and user-specific allocation information of its own allocations.

The at least one controller <NUM> may include a control signal parser <NUM>, and a scheduler <NUM> and a trigger information parser <NUM>. The control signal parser <NUM> may analyse the control signaling portions of the received signals (e.g. U-SIG fields and EHT-SIG fields of EHT basic PPDUs) and assist the data demodulator and decoder <NUM> in demodulating and decoding the data portions of the received signals (e.g. data fields of EHT basic PPDUs). The triggering information parser <NUM> may analyse the triggering information for its own uplink allocations from the received triggering frames contained in the data portions of the received signals. The transmission signal generator <NUM> may include a control signaling generator <NUM>, which may generate control signaling fields of PPDUs to be generated (e.g. U-SIG fields of EHT basic PPDUs or EHT TB PPDUs). The transmission signal generator <NUM> may further include a PPDU generator <NUM>, which generate PPDUs (e.g. EHT basic PPDUs or EHT TB PPDUs). The transmission signal generator <NUM> may further include a frame generator <NUM> may generate MAC frames, e.g. data frames.

As described above, the aspects of the present disclosure provide an advanced communication system, communication methods and communication apparatuses for control signalling in MIMO WLAN networks of an extremely high throughput and improve spectral efficiency in MIMO WLAN networks.

The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of each aspect described above can be partly or entirely realized by an LSI such as an integrated circuit, and each process described in each aspect may be controlled partly or entirely by the same LSI or a combination of LSIs. The LSI may be individually formed as chips, or one chip may be formed so as to include a part or all of the functional blocks. The LSI may include a data input and output coupled thereto. The LSI here may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on a difference in the degree of integration. However, the technique of implementing an integrated circuit is not limited to the LSI and may be realized by using a dedicated circuit, a general-purpose processor, or a special-purpose processor. In addition, a FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI or a reconfigurable processor in which the connections and the settings of circuit cells disposed inside the LSI can be reconfigured may be used. The present disclosure can be realized as digital processing or analogue processing. If future integrated circuit technology replaces LSIs as a result of the advancement of semiconductor technology or other derivative technology, the functional blocks could be integrated using the future integrated circuit technology. Biotechnology can also be applied.

The present disclosure can be realized by any kind of apparatus, device or system having a function of communication, which is referred to as a communication apparatus.

The communication apparatus may comprise a transceiver and processing/control circuitry. The transceiver may comprise and/or function as a receiver and a transmitter. The transceiver, as the transmitter and receiver, may include an RF (radio frequency) module including amplifiers, RF modulators/demodulators and the like, and one or more antennas.

Some non-limiting examples of such a communication apparatus include a phone (e.g. cellular (cell) phone, smart phone), a tablet, a personal computer (PC) (e.g. laptop, desktop, netbook), a camera (e.g. digital still/video camera), a digital player (digital audio/video player), a wearable device (e.g. wearable camera, smart watch, tracking device), a game console, a digital book reader, a telehealth/telemedicine (remote health and medicine) device, and a vehicle providing communication functionality (e.g. automotive, airplane, ship), and various combinations thereof.

The communication apparatus is not limited to be portable or movable, and may also include any kind of apparatus, device or system being non-portable or stationary, such as a smart home device (e.g. an appliance, lighting, smart meter, control panel), a vending machine, and any other "things" in a network of an "Internet of Things (IoT)".

The communication apparatus also may include an infrastructure facility, such as a base station, an access point, and any other apparatus, device or system that communicates with or controls apparatuses such as those in the above non-limiting examples.

It will be understood that while some properties of the various aspects have been described with reference to a device, corresponding properties also apply to the methods of various aspects, and vice versa.

Claim 1:
A communication apparatus (<NUM>) comprising:
circuitry (<NUM>) configured to generate an Extremely High Throughput Physical layer Protocol Data Unit, EHT PPDU, (<NUM>)comprising a Universal Signal, U-SIG, field (<NUM>) and an EHT Signal, EHT-SIG, field (<NUM>), wherein the U-SIG field comprises punctured channel information, and the EHT-SIG field comprises supplemental punctured channel information; and
a transmitter (<NUM>) configured to transmit the EHT PPDU,
characterized in that
when the EHT PPDU is used for punctured single-user, SU, or multi-user, MU, multiple input multiple output, MIMO, transmission and the punctured channel information is able to indicate a channel puncturing pattern that is applied to the EHT PPDU, the EHT-SIG field does not comprise the supplemental punctured channel information.