Method and apparatus for reducing peak-to-average power ratio in transmission of physical layer protocol data units

Abstract

To provide a communication device that reduces the peak-to-average power ratio (PAPR) of a trigger-based (TB) PPDU, especially of a universal signal (U-SIG) field, and improves the transmission performance of the PPDU.SOLUTION: A communication device includes a processor that receives a trigger frame in a first PPDU and obtains a sequence of ignore bits in a U-SIG field in the first PPDU. The sequence of ignore bits includes at least one bit set to 0, which is copied to a U-SIG field of a second PPDU. The communication device also includes a transmitter for transmitting the second PPDU, and the second PPDU includes a sequence of ignore bits. Using the sequence of ignore bits including at least one bit set to 0 enables PAPR reduction, causes an STA to refrain from increasing power amplifier back-off, and makes it possible to transmit with greater efficiency.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to wireless communication systems, and more particularly, to systems and methods for reducing peak-to-average power ratio (PAPR) in a universal signal (U-SIG) field of a physical layer protocol data unit (PPDU). [Background technology]

[0002] The U-SIG field is used in IEEE Standard 802.11 be (Standard for Information Technology--Communications and Information Exchange Between Systems in Local and Metropolitan Area Networks dated May 2021) to convey information about various important parameters such as the standardization version (802.11 be or later), bandwidth, and number of Very High Throughput EHT Signal (EHT-SIG) symbols to all receivers, including both Access Points (APs) and / or Stations (STAs). The U-SIG consists of two Orthogonal Frequency Division Multiplexing (OFDM) symbols, each of which contains 26 information bits.

[0003] The standard 802.11be is divided into two releases, Release 1 and Release 2, with Release 2 being under research, and some bits in the U-SIG field are reserved. There is agreement to separate these reserved bits into two types: - Validation bits - used by the receiver to decide whether to continue receiving the packet or to terminate reception. For example, a Release 1 receiver may realise that the packet is intended for a Release 2 receiver and therefore it can terminate reception. - A sequence of ignore bits - defined as "don't care" and typically ignored by the receiver.

[0004] Both the validation bit and the ignore bit sequences may be used for other purposes within Release 2. In a trigger-based (TB) PPDU, the sequence of ignore bits is copied from a trigger frame that is sent by the AP to instruct the STAs that they can begin transmitting, as well as information related to their transmissions (e.g., where to transmit, what modulation scheme to use, etc.).

[0005] Sequences of ignored bits can cause performance issues for the TB PPDU. For example, if all ignored bits are set to 1, this will result in an unnecessarily high PAPR of the entire U-SIG field, which will require the transmitting STA to increase the backoff of its power amplifier, which will reduce the transmit power. If the STA does not increase the backoff, the high PAPR can cause distortions in the transmitted signal (e.g. due to clipping of the time domain signal). Summary of the Invention

[0006] An objective of the present disclosure is to provide a method and apparatus for reducing the PAPR for transmitting a TB PPDU, especially the PAPR of the U-SIG field, thereby improving the transmission performance of the PPDU.

[0007] These and other objects are achieved by means of the features of the independent claims. Further implementations become apparent from the dependent claims, the description and the drawings.

[0008] According to a first aspect of the present disclosure, a communication device is disclosed for transmitting a physical layer protocol data unit (PPDU) to one or more receiving devices. The communication device includes a processor configured to receive a trigger frame in a first PPDU and obtain a sequence of ignore bits in a universal signal U-SIG field in the first PPDU. The sequence of ignore bits includes at least one bit set to 0 and is copied to a U-SIG field of a second PPDU. The communication device further includes a transmitter configured to transmit a second PPDU, where the second PPDU includes the sequence of ignore bits. Using the sequence of ignore bits including at least one bit set to 0 allows a reduced peak-to-average power ratio (PAPR) to be achieved, thereby allowing a STA to refrain from increasing a backoff of a power amplifier and transmit with higher efficiency. Alternatively, the communication device reduces the probability that the STA's transmissions, particularly the transmissions of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0009] In a further implementation of the first aspect, the U-SIG field includes at least a first U-SIG symbol and a second U-SIG symbol.

[0010] In a further implementation of the first aspect, the processor is configured to obtain a sequence of ignore bits by obtaining one of the sequences in the set {1111111110, 11111011110, 01111111110}. Using any of the sequences in the set as the sequence of ignore bits allows a further reduced peak-to-average power ratio (PAPR) to be achieved, thereby allowing the STA to refrain from increasing the back-off of the power amplifier and transmit more efficiently. Alternatively, it reduces the probability that the STA's transmissions, particularly the transmission of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0011] According to a second aspect of the present disclosure, an access point for transmitting a physical layer protocol data unit (PPDU) to one or more communication devices is disclosed, the access point including a processor configured to set a field of a trigger frame to a sequence including at least one zero, the access point further including a transmitter configured to transmit the PPDU to the one or more communication devices, the PPDU including a field of the trigger frame, the field of the trigger frame being configured to be copied by the one or more communication devices into an ignore bit of a universal signal U-SIG sequence.

[0012] In a further implementation of the second aspect, the field of the trigger frame may be, for example, a special user information field.

[0013] In a further implementation of the second aspect, the processor of the access point is configured to set the field of the trigger frame by setting the field to one of the sequences in the set {1111111110, 11111011110, 01111111110}. Using any of the sequences in the set as a sequence of ignore bits may achieve a further reduced peak-to-average power ratio (PAPR), thereby forcing the STA to refrain from increasing the backoff of its power amplifier and transmitting more efficiently, or may reduce the probability that the STA's transmissions, particularly the transmission of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0014] According to a third aspect of the present disclosure, a method for transmitting a physical layer protocol data unit (PPDU) in a communication device is disclosed. The method includes the steps of receiving a trigger frame in a first PPDU; and obtaining a sequence of ignore bits in a universal signal U-SIG field in the first PPDU, the sequence of ignore bits including at least one bit set to 0. The method further includes the steps of copying the sequence of ignore bits to a U-SIG field of a second PPDU; and transmitting the second PPDU including the sequence of ignore bits. Using the sequence of ignore bits including at least one bit set to 0 allows a reduced peak-to-average power ratio (PAPR) to be achieved, thereby allowing a STA to refrain from increasing a back-off of a power amplifier and transmit with higher efficiency. Alternatively, the method reduces the probability that the STA's transmissions, particularly the transmissions of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0015] In a further implementation of the third aspect, the U-SIG field includes at least a first U-SIG symbol and a second U-SIG symbol.

[0016] In a further implementation of the third aspect, obtaining the sequence of ignore bits includes obtaining one of the sequences in the set {11111111110, 11111011110, 01111111110}. Using any of the sequences in the set as the sequence of ignore bits may achieve a further reduced peak-to-average power ratio (PAPR), thereby allowing the STA to refrain from increasing the back-off of the power amplifier and transmit more efficiently, or reduce the probability that the STA's transmissions, particularly the transmission of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0017] According to a fourth aspect of the present disclosure, a method for transmitting a physical layer protocol data unit (PPDU) at an access point is disclosed. The method includes the steps of: setting a field of a trigger frame to a sequence including at least one zero; and transmitting the PPDU to one or more communication devices, the PPDU including a field of the trigger frame, the field of the trigger frame being configured to be copied by the one or more communication devices to an ignore bit of a universal signal U-SIG sequence. Using a sequence of ignore bits including at least one bit set to zero allows a reduced peak-to-average power ratio (PAPR) to be achieved, thereby allowing the STA to refrain from increasing the back-off of a power amplifier and transmit with higher efficiency. Alternatively, it reduces the probability that the STA's transmissions, particularly the transmission of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0018] In a further implementation of the fourth aspect, obtaining the sequence of ignore bits includes obtaining one of the sequences in the set {11111111110, 11111011110, 01111111110}. Using any of the sequences in the set as the sequence of ignore bits may achieve a further reduced peak-to-average power ratio (PAPR), thereby allowing the STA to refrain from increasing the back-off of the power amplifier and transmit more efficiently, or reduce the probability that the STA's transmissions, particularly the transmission of the U-SIG field, will suffer distortion caused by a high PAPR (e.g., due to clipping).

[0019] According to a fifth aspect of the present disclosure, a machine-readable storage medium is disclosed having processor-executable instructions stored thereon that, when executed by a processor of a device, cause the device to perform a method according to any of the disclosed methods.

[0020] According to a sixth aspect of the present disclosure, a computer program product is disclosed that includes a computer readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a device including processing hardware to perform any of the disclosed methods. According to a seventh aspect of the present disclosure, a computer storage medium or computer program product for any method of reducing PAPR is disclosed.

[0021] Other devices, methods, features and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following figures and detailed description, and it is intended that all such additional devices, methods, features and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

[0022] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art with respect to the embodiments. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the embodiments, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. Additionally, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. [Brief description of the drawings]

[0023] Certain embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Referring now specifically to the drawings in detail, it is emphasized that the particulars shown are exemplary and are for the purposes of explanation of the embodiments, and in this regard, the description taken together with the drawings will make apparent to those skilled in the art how the embodiments may be practiced. [Figure 1] FIG. 1 illustrates a system for reducing the PAPR in a field of a PPDU in accordance with some embodiments of the present disclosure. [Diagram 2] Figure 2 shows the U-SIG design for the 802.11be Release 1 TB PPDU. [Diagram 3] FIG. 3 shows the complementary cumulative distribution function (CCDF) of the PAPR of the U-SIG-1 and U-SIG-2 symbols with a BW of 320 MHz. [Figure 4] FIG. 4 shows the complementary cumulative distribution function (CCDF) of the PAPR of the U-SIG-1 and U-SIG-2 symbols with a BW of 40 MHz. [Diagram 5] FIG. 5 is a schematic diagram of a possible logical structure of a communication device according to some embodiments of the present disclosure. [Figure 6] Figure 6 shows the CCDF of the PAPR using the ignore bit sequence '11111111110' compared to the ignore bit sequence '111111111111' assuming a BW of 320 MHz without puncturing. [Figure 7] Figure 7 shows the CCDF of the PAPR using the ignore bit sequence '11111111110' compared to the ignore bit sequence '11111111111' assuming a BW of 320 MHz with puncturing pattern 1111111100001111. [Figure 8] Figure 8 shows the CCDF of the PAPR for U-SIG-1 using ignore bit sequences '11111011110' and '01111011110' compared to the ignore bit sequence '11111111111' assuming 320 MHz without puncturing. [Figure 9] Figure 9 shows the CCDF of PAPR for U-SIG-2 using ignore bit sequences '11111011110' and '01111011110' compared to ignore bit sequence '11111111111' assuming 320 MHz without puncturing. [Figure 10] FIG. 10 illustrates the structure of the special user information field in the trigger frame relevant to the context of this disclosure. [Figure 11] FIG. 11 illustrates the "U-SIG Ignore and Verify" field used in the context of this disclosure to convey the ignore bit sequence. [Figure 12] FIG. 12 is a workflow of a method for transmitting a physical layer protocol data unit PPDU in a communication device. [Figure 13] FIG. 13 is a workflow of a method for transmitting a physical layer protocol data unit PPDU in an access point. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Before describing at least one embodiment in detail, it should be understood that the embodiments are not necessarily limited in this case to the details of construction and arrangement of components and / or methods set forth in the following description and / or drawings and / or specific examples, as implementations described herein may have the capabilities of other embodiments or be implemented or carried out in various ways.

[0025] FIG. 1 illustrates a system for reducing the PAPR in a field of a PPDU according to some embodiments of the present disclosure. The system 100 includes an access point (AP) 101 and one or more stations (STAs), such as STA 102, STA 103, and STA 104, as shown in FIG. 1. The system 100 is also referred to as a basic service set (BSS) in this disclosure. In the system 100, the AP and the STAs communicate on both the downlink and the uplink. The arrow between the AP and the STAs shown in FIG. 1 indicates only the downlink, but should not be understood as a transmission limitation.

[0026] Although system 100 shows only one AP in the system, the system may include multiple APs in the system, and the APs in the system may perform cooperative transmissions.

[0027] The system 100 of the present disclosure includes, but is not limited to: Wireless Fidelity (WIFI) communication systems, Narrowband Internet of Things (NB-IoT) systems, Long Term Evolution (LTE) systems, Fifth Generation Mobile Communication Systems (5G) or later, Machine-to-Machine (M2M) communication systems, etc. LTE systems and 5G or later can integrate WIFI systems.

[0028] In this disclosure, the communication device is an AP 101 or a STA, which may be, for example, a mobile phone, an intelligent terminal, a tablet computer, a notebook computer, a video game console, a multimedia player, a vehicle that supports WIFI, a device-to-device (D2D) device, or any smart device. The AP and / or the STA may be a fixed or mobile device.

[0029] The WIFI system may support all Institute of Electrical and Electronics Engineers (IEEE) 802.11 series including, but not limited to, 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, 802.11be or later.

[0030] Figure 2 shows the U-SIG design for the TB PPDU in 802.11be Release 1. The bits in the first symbol of the U-SIG for the TB PPDU carry information about the PHY version (e.g., 802.11be or later version of the standard), the BW (e.g., 20 MHz, 40 MHz, etc.), whether it is DL or UL transmission, the BSS color to distinguish different possible neighboring BSS values, the duration of the TXOP, and / or how the transmitter is utilizing the channel resources. The bits in the second symbol of the U-SIG carry information about the PPDU type (e.g., MU, TB), and the spatial reuse (e.g., spatial reuse 1 and spatial reuse 2), which allows multiple transmitters to transmit simultaneously on the same resources the 6 zero-tail bits used for CRC and convolutional code.

[0031] As shown in both Figure 2, a sequence of ignored bits is placed in the first and second U-SIG symbols; however, because the CRC is calculated as a function of all preceding bits including both the first and second U-SIG symbols, the value of the CRC bits (those placed in the second U-SIG symbol) is also a function of the sequence of ignored bits placed in the first U-SIG symbol.

[0032] In 802.11ax, the trigger frame contains 9 reserved bits, with all 9 bits set to '1'. The 9 reserved bits are copied to the second symbol of the HE-SIG-A field of the TB PPDU. In the current 802.11be development stage, there are 6 sequences of ignore bits in the first U-SIG symbol and 5 sequences of ignore bits in the second U-SIG symbol per TB PPDU. All sequences of ignore bits are currently (in the current development stage of 802.11be) defined to be copied from the trigger frame (similar to 802.11ax operation). In 11be, keeping the same design as in 11ax, the sequences of ignore bits copied from the trigger frame may be set to 1.

[0033] Although the structure of the trigger frame is not presented in this disclosure, the sequence of ignore bits in the trigger frame and the TB PPDU may contain consecutive binary bits '1', which may result in a high PAPR and, as a result, the performance of the U-SIG field for the TB PPDU will be affected (e.g., using a lower PAPR may reduce the back-off of the power amplifier, thereby increasing efficiency).

[0034] FIG. 3 shows the complementary cumulative distribution function (CCDF) of the PAPR of both U-SIG symbols for a BW of 320 MHz (in FIG. 3, U-SIG-1 means the first symbol of the U-SIG field, and U-SIG-2 means the second symbol of the U-SIG field). The sequence of ignored bits in the U-SIG symbols is assumed to be all 1's. FIG. 3 shows the complementary cumulative distribution function (CCDF) of the PAPR of both U-SIG symbols, compared with that of the data part (assuming MCS0=BPSK rate 1 / 2) and that of the Legacy SIG (L-SIG) field. As shown, the U-SIG PAPR is significantly higher than that of the data, and also higher than that of the L-SIG field, especially the PAPR of the U-SIG-2 symbol.

[0035] Figure 4 shows the CCDF of the PAPR of both U-SIG symbols for a BW of 40 MHz. The effect shown in relation to Figure 5 is shown to be consistent for other BW values ​​and puncturing patterns. Figure 4 shows a similar comparison with a BW of 40 MHz. As shown there, the PAPR of both U-SIG symbols also exceeds that of the L-SIG field and data payload.

[0036] Current standards specify that the pre-EHT fields, which are replicated every 20 MHz portion (e.g. L-SIG, U-SIG, etc.), are subject to a phase rotation every 20 MHz to reduce the PAPR. However, as shown in Figures 3 and 4, the U-SIG PAPR is higher than both the data and L-SIG, meaning that it is a limiting factor in terms of performance (which may dictate a backoff of the power amplifier).

[0037] Therefore, it is important to reduce the PAPR of the U-SIG field, as can be seen from Figures 3 and 4 based on simulation results.

[0038] To solve the above problems, the present disclosure provides a method and / or apparatus for reducing the PAPR of a TB PPDU, especially the PAPR of a U-SIG field.

[0039] The embodiments presented in this disclosure may be systems, methods, and / or computer program products that may include a computer-readable storage medium (or media) having computer-readable program instructions for causing a processor to perform aspects of the embodiments.

[0040] A computer readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device, such as, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof.

[0041] A non-exhaustive list of more specific examples of computer readable storage media includes: portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disk (DVD), memory stick, floppy disk, and any suitable combination of the above.

[0042] As used herein, computer-readable storage media should not be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., light pulses through a fiber optic cable), or electrical signals transmitted over wires.

[0043] The computer readable program instructions described herein may be downloaded from a computer readable storage medium into each computing / processing device or downloaded to an external computer or storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. A network adapter card or network interface in each computing / processing device may receive the computer readable program instructions from the network and transfer the computer readable program instructions for storage in the computer readable storage medium within each computing / processing device.

[0044] The computer readable program instructions for carrying out the operations of the embodiments may be either assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, or conventional procedural programming languages, such as the “C” programming language or similar programming languages.

[0045] The computer readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be to an external computer (e.g., via the Internet using an Internet Service Provider).

[0046] In some embodiments, electronic circuitry including, for example, a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) may execute computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry to perform aspects of the embodiments.

[0047] FIG. 5 is a schematic diagram of a possible logical structure of a communication device in the present disclosure according to some embodiments. The communication device includes a processor 402. In some embodiments of the present disclosure, the processor 402 may be configured to control and manage one or more operations of the communication device, for example, to execute code that operates on a sequence of ignore bits to reduce PAPR and / or to process data transmitted and / or received at the AP. Optionally, the communication device may further include a memory 401 and a communication interface 403. The processor 402, the communication interface 403, and the memory 401 may be interconnected or may be interconnected using a bus 404. The communication interface 403 is configured to support the communication device in performing communications, and the memory 401 is configured to store program codes and data for the communication device. The processor 402 invokes the codes stored in the memory 401 to perform the control and management. The memory 401 may or may not be coupled to the processor 402.

[0048] The processor 402 may be a central processing unit, a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 402 may implement or execute various exemplary logic blocks, modules, and circuits described with reference to the disclosed subject matter in this disclosure. Alternatively, the processor 402 may be a combination of processors that implement computing functions, such as a combination of one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 404 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be classified as an address bus, a data bus, a control bus, or the like.

[0049] According to the communication device provided above, in some embodiments, the U-SIG may include at least a first U-SIG symbol and a second U-SIG symbol.

[0050] The sequence of ignored bits in this disclosure may be a predefined bit sequence in the prior art, such as current IEEE protocols. The sequence of ignored bits in some embodiments may be 5 or 6 bits, with all bits set as binary '1' in the TB PPDU. The sequence of ignored bits may refer to a 6-bit sequence of ignored bits in the first U-SIG symbol in the TB PPDU and / or a 5-bit sequence of ignored bits in the second U-SIG symbol in the TB PPDU. It should be noted that the sequence of ignored bits may include other numbers of binary bits, and 5 or 6 bits is not a limitation in this disclosure.

[0051] Figure 6 shows the CCDF of the PAPR assuming a ignore bit sequence with all bits set to '1' except for a single '0' at the edge of either U-SIG-1 or U-SIG-2, assuming no puncturing and 320 MHz. In particular, the sequence '111111' in U-SIG-1 and the sequence '11110' in U-SIG-2 (which totals '11111111110') are shown, which results in the lowest PAPR. Figure 7 compares the CCDF of the PAPR for the all-ones case with that of the '11111111110' sequence with a single '0' at the end of the sequence, assuming no puncturing and 320 MHz. The CCDF curves of U-SIG-1 for both '11111111111' and '111111111110' are identical, since the first six values ​​are the same for both sequences. For U-SIG-2, an improvement with a single '0' can be observed.

[0052] Figure 7 shows a comparison between the CCDF of the PAPR for the all ones case and that of a sequence of ignore bits with a single '0' at the end of the sequence, assuming 320 MHz with puncturing pattern 1111111100001111. Again, the CCDF curve for U-SIG-1 lies close since the first six values ​​are the same for both sequences. For U-SIG-2, an improvement with the single '0' can be observed.

[0053] Figure 8 shows an example where all bits are set to '1' except for a single '0' on both edges of U-SIG-1 and U-SIG-2. In other words, there is one '0' in U-SIG-1 and one '0' in U-SIG-2, with two values ​​of '0' used throughout the sequence.

[0054] In particular, the following sequence is shown in Figure 8: - '111110' in U-SIG-1 and '11110' in U-SIG-2 (hence the total '11111011110') - '011111' in U-SIG-1 and '11110' in U-SIG-2 (hence '01111111110' in total)

[0055] Figure 8 shows a comparison of the CCDF of the PAPR for the all ones case with that of the sequence proposed above, assuming 320 MHz without puncturing, for U-SIG-1. As shown in Figure 8, there is an improvement in the PAPR.

[0056] Figure 9 shows a comparison of the CCDF of the PAPR for the all ones case for U-SIG-2, assuming 320 MHz without puncturing, with that of the same sequence as in Figure 8. As shown in Figure 9, there is an improvement in the PAPR.

[0057] 10 illustrates a special user information field from an example trigger frame of the present disclosure. In the example of the present disclosure, the field between B25 and B36 is a field where a ignore bit sequence is transmitted from the access point and can be used as a field to be received by the communication device and used as an ignore bit string, thereby achieving a reduced PAPR.

[0058] Figure 11 shows the definition of the "U-SIG Ignore and Verify" subfield and the copying of the ignore bit sequence into the U-SIG field.

[0059] 12 shows a workflow of a method for transmitting a physical layer protocol data unit (PPDU) in a communication device. The method includes a step S1 of receiving a trigger frame in a first PPDU. The method further includes a step S2 of obtaining a sequence of ignore bits in a universal signal U-SIG field in the first PPDU, where the sequence of ignore bits includes at least one bit set to 0. The method also includes a step S3 of copying the sequence of ignore bits to a U-SIG field of a second PPDU, and a step S4 of transmitting the second PPDU, where the second PPDU includes the sequence of ignore bits.

[0060] 13 shows a workflow of a method for transmitting a physical layer protocol data unit (PPDU) in an access point. The method includes a step S1 of setting a field of a trigger frame to a sequence including at least one zero. The method further includes a step S2 of transmitting the PPDU to one or more communication devices, where the PPDU includes a field of the trigger frame, where the field of the trigger frame is set to be copied by the one or more communication devices into an ignore bit of a universal signal U-SIG sequence.

[0061] The description of various embodiments is provided for illustrative purposes, but is not intended to be exhaustive or limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications or technical improvements beyond those found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0062] The terms "including," "including," "including," "including," "having," and conjugations thereof mean "including but not limited to."

[0063] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" can include a plurality of compounds, including mixtures thereof.

[0064] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0065] The word "optionally" is used herein to mean "provided in some embodiments and not provided in other embodiments." Any particular embodiment may include more than one "optional" feature, unless such features conflict.

[0066] Throughout this application, various embodiments may be presented in a range format. It should be understood that the description in a range format is for convenience only and should not be construed as an inflexible limitation on the scope of the embodiments.

[0067] It will be appreciated that certain features of embodiments that are, for clarity, described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of an embodiment that are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable subcombination or in any other described embodiment, as appropriate. Certain features described in the context of various embodiments should not be considered essential features of those embodiments unless the embodiment is inoperable without those elements.

[0068] While the embodiments have been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0069] Although this disclosure describes a solution for reducing the PAPR from the perspective of an apparatus, it is clear to those skilled in the art that the problems addressed in this disclosure can also be implemented by a method and / or a system. In order to avoid redundancy, the method for reducing the PAPR is not detailed.

[0070] It is the intention of the applicants that all publications, patents, and patent applications mentioned herein, when incorporated by reference herein, are incorporated by reference in their entirety into the specification as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. Furthermore, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the embodiments. To the extent section headings are used, they should not be construed as necessary limitations.

Claims

1. 1. A communications device for transmitting a physical layer protocol data unit (PPDU) to one or more receiving devices, the communications device comprising: receiving a trigger frame in a first PPDU; obtaining a sequence of ignored bits of a universal signal U-SIG field in the first PPDU, wherein at least a most significant bit or a least significant bit in the sequence of ignored bits is set to 0; and a processor configured to perform the step of copying the sequence of ignore bits into a U-SIG field of a second PPDU; and a transmitter configured to transmit the second PPDU, the second PPDU including the sequence of ignore bits; A communication device including:

2. 2. The communications device of claim 1, wherein the U-SIG field includes at least a first U-SIG symbol and a second U-SIG symbol.

3. 3. A communications device as claimed in claim 1 or 2, wherein the processor is configured to obtain the sequence of ignored bits by obtaining one of the sequences in the set {11111111110, 11111011110, 01111111110}.

4. 1. An access point for transmitting physical layer protocol data units (PPDUs) to one or more communication devices, said access point comprising: a processor configured to set a field of the trigger frame to a sequence including at least one zero; and a transmitter configured to transmit the PPDU to the one or more communication devices, the PPDU including the field of the trigger frame, the field of the trigger frame configured to be copied by the one or more communication devices into an ignore bit of a universal signal U-SIG sequence; An access point including.

5. 5. The access point of claim 4, wherein the processor is configured to set the field of the trigger frame by setting the field to one of a sequence in the set: {11111111110, 11111011110, 01111111110}.

6. 1. A method for transmitting a physical layer protocol data unit (PPDU) in a communication device, the method comprising: receiving a trigger frame in a first PPDU; obtaining a sequence of ignored bits of a universal signal U-SIG field in the first PPDU, where in the sequence of ignored bits, at least a most significant bit or a least significant bit is set to 0; copying the sequence of ignore bits into a U-SIG field of a second PPDU; and transmitting the second PPDU, the second PPDU including the sequence of ignore bits; The method includes:

7. 7. The method of claim 6, wherein the U-SIG field includes at least a first U-SIG symbol and a second U-SIG symbol.

8. 8. A method according to claim 6 or 7, wherein obtaining the sequence of ignored bits comprises obtaining one of the sequences in the set {11111111110, 11111011110, 01111111110}.

9. 1. A method for transmitting a physical layer protocol data unit (PPDU) in an access point, the method comprising: setting a field of the trigger frame to a sequence including at least one zero; and transmitting the PPDU to the one or more communication devices, the PPDU including the field of the trigger frame, the field of the trigger frame configured to be copied by the one or more communication devices into an ignore bit of a universal signal U-SIG sequence; The method includes:

10. 10. The method of claim 9, wherein the processor obtaining the sequence of ignored bits comprises obtaining one of the sequences in the set: {11111111110, 11111011110, 01111111110}.

11. 11. A machine-readable storage medium having stored thereon processor-executable instructions which, when executed by a processor of a device, cause the device to perform a method according to any one of claims 6 to 10.

12. A computer program product comprising a computer readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a device including processing hardware to perform the method of any one of claims 6 to 10.

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